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Background: Using infection control barriers (ICBs) on light curing units (LCUs) became mandatory to achieve proper infection control measures without jeopardizing the integrity of the restorations, especially at deeper layers. This study explored the effect of two ICBs on the irradiance of the LCU, as well as the degree of conversion (DC) and flexural strength (FS) of two types of bulk-fill composites. Water vapor permeability (WVP) of both barriers was also assessed to evaluate the capability of such barriers to prevent transmission of blood and saliva droplets and aerosols., Methods: Two bulk-fill composites (X-tra fil and Tetric N- ceram) and two ICBs (Pinnacle Cure sleeve and Sanita wrapping film) were used in this study. Light irradiance was recorded per experimental condition using spectroradiometer. For DC and FS, specimens of 4 mm thickness were prepared. Each specimen was composed of two separable upper and lower layers of thickness 2 mm. DC and FS were measured using Infra-red spectroscopy and three-point loading test respectively. WVP was investigated using the cup method. Means and standard deviations were calculated, and the data were statistically analyzed using factorial analysis of variance test (α = 0.05)., Results: Light irradiance showed highest values using no ICBs and lowest values using Pinnacle curing sleeve. Both bulk-fill composites showed higher DC mean values without ICBs and when using Sanita wrapping film for both upper and lower layers of the specimens compared to Pinnacle curing sleeve. The upper layers of composite specimens showed higher DC compared to lower layers for all experimental conditions. Both ICBs had no adverse effect on FS of both composites' upper layers. Pinnacle sleeve significantly reduced FS of both composites' lower layers. X-tra fil showed higher DC and FS compared to Tetric N-Ceram for all experimental conditions. Regarding WVP; the wrapping film showed higher WVP compared to the curing sleeve., Conclusions: Sanita wrapping film can be used as a successful ICB, without jeopardizing the concept of bulk-fill composites. Pinnacle cure sleeve can be considered an effective ICB, however its influence on properties and serviceability of bulk-fill composites remains questionable., (© 2024. The Author(s).)

The purpose of this study was to compare the flexural strength, Weibull modulus (reliability), marginal gap, and internal fit (internal gap) of 4 materials for milling or 3-dimensional (3D) printing of definitive and provisional crowns: IPS e.max CAD (IEC), Paradigm MZ100 Block (PMB), Permanent Crown Resin (PCR), and Temporary CB Resin (TCR). Flexural strength was tested by subjecting sectioned milling blocks (IEC and PMB) or 3D-printed bars (PCR and TCR) to a 3-point bending test in a universal testing machine (n = 15 per material). Crowns were milled or 3D printed, and the marginal gap and internal fit were measured using microcomputed tomography (n = 5 per material). The data were analyzed with a t test and compared using analysis of variance (ANOVA) with Tukey post hoc comparisons (α = 0.05). The groups demonstrated the following mean (SD) flexural strength values: IEC, 335.50 (28.97) MPa; PMB, 154.34 (21.03) MPa; PCR, 128.09 (7.30) MPa; and TCR, 126.29 (9.23) MPa. A 1-way ANOVA revealed significant differences in the flexural strengths of sectioned and 3D-printed bars (P < 0.001). The PMB group showed the lowest Weibull modulus (8.77), indicating its poor reliability. The IEC group showed the smallest marginal gap, 53.42 (31.99) μm; this value was significantly smaller than the gap in the TCR group (P < 0.001) but not the PCR or PMB group. The PMB group had the smallest internal fit discrepancy (87.44 [37.60] μm) but was not significantly different from PCR, while TCR had a significantly greater internal fit discrepancy (130.61 [65.16] μm) than IEC, PMB, and PCR (P < 0.001). The occlusal internal fit discrepancies of 3D-printed crowns were significantly greater than those of milled crowns (P < 0.001). There was no statistically significant difference in flexural strength between the 3D-printed definitive (PCR) and provisional (TCR) materials. When the data were combined according to manufacturing method, the marginal gap and internal fit of crowns fabricated with 3D printing were comparable to those of milled crowns, and all mean marginal gaps were within a clinically acceptable limit of less than 120 μm., Competing Interests: No conflicts of interest reported.

Objectives: This study aimed to assess color matching post-repair using the same or different single-shade composites of three distinct composite resin materials (Omnichroma-OM, ZenChroma-ZC, and Charisma Topaz One-CTO) following aging in coffee solution and distilled water. Evaluation focused on color change parameters (∆E00, ∆L00, ∆C00, and ∆H00)., Methods and Materials: Specimens were prepared in disk shape with a diameter of 8 mm and a height of 2 mm (n=180). Half of each composite group was immersed in distilled water, while the other half was immersed in coffee solution for 12 days each (n=90). After aging, cylindrical cavities with a diameter of 4 mm and a depth of 1 mm were prepared at the center of the specimens. The cavities were repaired with both themselves and other composite resins (n=10). Color measurements of the specimens were performed using VITA Easyshade 5 (VITA Zahnfabrik, Bad Säckingen, Germany) at the following time points: baseline (T0), after aging (12 days) (T1), immediately after repair (T2), one day after repair (T3), one week after repair (T4), and one month after repair (T5)., Results: Statistically significant differences were found in the mean ΔE00 measurements among the study groups at all time points for each of the three composite resins (p<0.05). Similarly, statistically significant differences were found in the mean ΔE00 measurements over time for each of the three composite resins in each study group (p<0.05). The baseline measurements of materials repaired with themselves in the distilled water groups and the final measurements of materials repaired with themselves in the coffee groups were found to be within acceptable ∆E00limits. At the end of the study, only CTO repaired with OM showed acceptable color matching with different composites in both coffee and distilled water groups., Conclusions: Acceptable color matching was achieved when using the same material for repair in specimens aged in distilled water and coffee. However, variations in matching were observed when different materials were used for repair, indicating the need for ongoing monitoring. Contributions of ΔL00, ΔC00, and ΔH00 values to color differences vary depending on the resins and repair process and change over time., (©Operative Dentistry, 2024.)

Objectives: The aim of the present prospective study was to evaluate the colour stability of 3D-printed non-invasive restorations after 24 months in vivo., Methods: The study included 29 patients, who received 3D-printed restorations made of a computer-aided design (CAD) / computer aided-manufacturing (CAM) hybrid material (n = 354). Restoration colour of 190 restorations was measured using a spectrophotometer. By applying the CIELAB system, *L (lightness), a* (red-green) and b* (blue-yellow) values were recorded. An evaluation of the colour differences (ΔE) after 6, 12 and 24 months was conducted., Results: Analysis of colour differences of 3D-printed restorations showed continuous discolouration of the restorations. After one year 34 % and after two years 18 % of the restorations were rated alpha or bravo, indicating no or hardly visible colour change. After two years, 54 % of the evaluated restorations yielded a colour difference with ΔE > 6.8 (delta). More than 82 % of the evaluated restorations showed values between ΔE 3.8 - 6.8 (charlie) and ΔE ˃ 6.8 (delta) after two years., Conclusions: 3D-printed non-invasive restorations showed an overall reduced colour stability after 24 months in vivo., Clinical Significance: The present study provides first clinical data regarding 3D-printed restorations. These restorations are recommended for a wearing time of about 6 months., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Elisabeth Prause reports equipment, drugs, or supplies was provided by BEGO. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To evaluate the effects of different stamp materials and restoration depths on the accuracy of direct composite resin restorations using stamp technique., Methods: Eighty standard resin teeth were divided into four groups based on different stamp materials: flowable composite resin (FR), vinyl polydimethyl siloxane (VPS) for bite registration (VB), VPS for impression (VI) and transparent VPS (TV). Each material group was further divided into two subgroups based on restoration depth (1 and 2 mm; n = 10). Standardized Class I cavities were prepared and restored with the corresponding stamps. Pre- and post-treatment scans of each tooth were fitted using Geomagic Control X software, generating deviation distribution maps of the occlusal surface. The accuracy indicators, including mean height variation (MHV), root mean square (RMS), and proportions of height variation with different ranges (PHV range ), were recorded to evaluate the accuracy of restorations. Analysis of variance (ANOVA) were used for statistical analysis (α=0.05)., Results: The type of stamp material significantly affected all accuracy indicators, while restoration depth did not show a significant effect on any of the indicators. MHV values ranged from 29.70 ± 5.88 μm to 63.52 ± 9.58 μm, and RMS values ranged from 62.78 ± 8.76 μm to 101.79 ± 13.17 μm, displaying a trend of FR<0.05 mm values (72.24 ± 3.40 % for 1 mm, 71.47 ± 8.54 % for 2 mm) and the lowest PHV >0.2 mm values (0.70 ± 0.50 % for 1 mm, 0.94 ± 0.47 % for 2 mm). In contrast, the TV groups exhibited the lowest PHV <0.05 mm values (59.69 ± 10.23 % for 1 mm, 59.67 ± 5.70 % for 2 mm), while the VI groups showed the highest PHV >0.2 mm values (7.34 ± 1.58 % for 1 mm, 8.20 ± 3.16 % for 2 mm)., Conclusions: The accuracy of direct composite resin restorations using stamp made of flowable composite resin was higher than that of all tested VPS materials, thereby reducing the need for occlusal adjustment and improving clinical efficiency. Besides, restoration depth had no significant impact on the accuracy of stamp technique, regardless of the stamp material used., Clinical Significance: The accuracy of direct composite resin restorations using stamp technique with different stamp materials varies. The flowable composite resin stamp exhibits higher accuracy compared with VPS stamps, reducing the need for occlusal adjustments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: This study was designed to show that the commonly reported irradiance values that are quoted in most publications inadequately describe the light output from light curing units (LCUs)., Methods: The total spectral radiant power (mW) output from 12 contemporary LCUs was measured with a fiberoptic spectroradiometer and a calibrated integrating sphere. Five recordings were taken for each LCU and exposure mode. In addition, the irradiances (mW/cm²) delivered at 0-mm, 5-mm and 10-mm distances were recorded through a 6-mm diameter aperture and the radiant exposures (J/cm²) from the LCUs were calculated. Light beam profiles from the LCUs were recorded using a beam profiler, and the images were overlaid on a molar tooth to simulate a clinical setting. Data were analyzed using ANOVA followed by Tukey post-hoc test (α = 0.05)., Results: The mean power outputs from the LCUs ranged from 380 to 2472 mW (p < 0.0001). The highest irradiance was recorded from the Cicada CV 215-G7 (3091 mW/cm² in its highest mode) and the lowest from the Radii Cal CX (731 mW/cm²). The emission spectra differed, even among the multi-peak and single-peak LCUs. Radiant exposures from the entire light tip ranged from 18.3 J/cm², Radii Cal CX, in its standard 25 s exposure mode to 3.9 J/cm² from the Monet Laser in a 3 s exposure setting. Half (50 %) of the measured irradiance values from the LCUs differed from the manufacturers' value by more than 10 %. There were significant differences in the impact of distance from the tip. The beam profiles visually highlighted the varying effects of distance from the LCU tip among different units., Conclusion: There were significant differences in the emission spectra, power outputs, tip diameters, irradiances, radiant exposures, and the effect distance from the light tips. These differences underline the importance of manufacturers and researchers correctly measuring and reporting the output from the LCU to ensure that research is reproducible and that patients receive acceptable dental restorations., Clinical Significance: This article alerts clinicians, researchers and journal editors that providing only the tip irradiance (radiant exitance) value from the LCU is no longer sufficient. Manufacturers and researchers should include information on the spectral radiant power, emission spectrum, tip diameters, and also the effect of distance on the irradiance and radiant exposure, beam profiles and tooth access information when describing an LCU., Competing Interests: Declaration of competing interest The authors have no commercial or financial conflicts of interest with this manuscript., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: To assess the clinical performance of monolithic screw-retained implant-supported zirconia crowns (MSI) bonded or mechanically retained on prefabricated Ti-bases using a complete digital workflow., Methods: A retrospective analysis was conducted on patients who underwent single dental implant procedures between January 2017 and May 2018. Inclusion criteria were: patients over 18 years of age; implants placed in posterior sites; MSI on prefabricated Ti-base realized by using a complete digital workflow; a minimum follow-up period of 2 years. Cemented crowns and fixed dental prosthesis were excluded. Mechanical complications included: fracture of Ti-base; loss of retention; loosening of Ti-base screws. Technical complications included: fracture and debonding of monolithic zirconia. Biological complication was set strictly at a probing pocket depth of 5 mm and bleeding on probing or pus secretion., Results: A total of 144 dental implants placed in 127 patients were included, 73 with a fully tapered implant system (BLX) and 71 with a conical connection system (Nobel Parallel CC). Of the 73 BLX implants, 4 experienced loosening of the Ti-base screw, while 3 Nobel Parallel CC implants experienced the same problem. In addition, 4 fractures of the Ti-base and 6 fractures of the inner surface of the monolithic zirconia were observed in the Nobel Parallel CC implants. Cumulative survival was 100 % for bonded crowns and 85 % for mechanically retained crowns. Radiographic evaluation revealed a mean CBL of 0.12 mm for the BLX and 0.13 mm for the Nobel Parallel CC implants with no statistically significant differences between the Ti-base types. There was no evidence of bleeding on probing or pus secretion. All probing pocket depths were <3 mm., Conclusion: The use of a prefabricated Ti-base remains a clinically acceptable choice, however, MSIs bonded to prefabricated Ti-bases had fewer mechanical and technical complications than the MSI mechanically retained to a prefabricated Ti-base., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: To digitally evaluate the trueness and fit of additively and subtractively manufactured fixed complete dentures in materials intended for definitive use., Methods: An edentulous maxillary model with implants at the left first molar, left canine, right canine, and right first molar site was digitized and a fixed complete denture was designed. This design was used to fabricate fixed dentures in an additively manufactured resin for definitive use (AM), a high-impact polymer composite (SM-CR), and a strength gradient zirconia (SM-ZR) (n = 10). Each fixed denture was digitized and the surface (overall, occlusal, except occlusal, and abutments), linear, and interimplant distance deviations were analyzed. The fit was assessed with the triple-scan protocol. Data were analyzed with Welch analysis of variance and Games-Howell tests (α = 0.05)., Results: SM-ZR led to lower overall deviations than AM, which had the highest occlusal and the lowest abutments deviations (P ≤ 0.007). SM-ZR had the lowest occlusal and SM-CR had the highest except occlusal deviations (P ≤ 0.002). AM mostly had higher linear and SM-CR mostly had higher interimplant distance deviations (P ≤ 0.043). AM led to the highest marginal gap at the left canine site, while SM-CR had the highest and SM-ZR had the lowest gaps at the right canine site (P ≤ 0.022)., Conclusions: SM-ZR dentures mostly had trueness and marginal fit similar to or better than the other groups. Tested fixed complete dentures were mostly smaller than the design file in terms of interimplant distances., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objective: This article reviews the applications of Finite Element Models (FEMs) in personalized dentistry, focusing on treatment planning, material selection, and CAD-CAM processes. It also discusses the challenges and future directions of using finite element analysis (FEA) in dental care., Data: This study synthesizes current literature and case studies on FEMs in personalized dentistry, analyzing research articles, clinical reports, and technical papers on the application of FEA in dental biomechanics., Sources: Sources for this review include peer-reviewed journals, academic publications, clinical case studies, and technical papers on dental biomechanics and finite element analysis. Key databases such as PubMed, Scopus, Embase, and ArXiv were used to identify relevant studies., Study Selection: Studies were selected based on their relevance to the application of FEMs in personalized dentistry. Inclusion criteria were studies that discussed the use of FEA in treatment planning, material selection, and CAD-CAM processes in dentistry. Exclusion criteria included studies that did not focus on personalized dental treatments or did not utilize FEMs as a primary tool., Conclusions: FEMs are essential for personalized dentistry, offering a versatile platform for in-silico dental biomechanics modeling. They can help predict biomechanical behavior, optimize treatment outcomes, and minimize clinical complications. Despite needing further advancements, FEMs could help significantly enhance treatment precision and efficacy in personalized dental care., Clinical Significance: FEMs in personalized dentistry hold the potential to significantly improve treatment precision and efficacy, optimizing outcomes and reducing complications. Their integration underscores the need for interdisciplinary collaboration and advancements in computational techniques to enhance personalized dental care., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Several nanomaterials have been recently used to overcome various challenges in the dental domain. Bioactive glasses, a class of bioceramics, with their outstanding properties including but not limited to their strong biocompatibility, antibacterial characteristics, and bioactivity inside the body's internal milieu have made them valuable biomaterials in a variety of dental domains. The utilization of nanomaterials has improved the performance of teeth, and the incorporation of bioactive glasses has the field of dentistry at an unsurpassed level in different categories such as esthetic and restorative dentistry, periodontics and dental implants, orthodontics, and endodontics. The current study discusses the most recent developments of the bioactive glasses' creation and implementation for dental applications, as well as the challenges and opportunities still facing the field. This work provides an overview of the current obstacles and potential future prospects for bioactive glasses-based nanocomposites to improve their dental uses. It also emphasizes the great potential synergistic effects of bioactive glasses used with other nanomaterials for dental applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Paediatric-preformed zirconia crowns have been associated with several issues, primarily their inability to be crimped and the need for extensive tooth preparation. Additionally, the capacity to adjust the size, shape, and fit of these crowns is very limited., Aim: To evaluate and compare the fracture strength of four different types of dental crowns intended for paediatric patients., Design: The fracture resistance of four types of paediatric crowns was evaluated using the universal testing machine; freshly extracted primary molars received one of the following: preformed zirconia crowns, custom-made computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia crowns, custom-made CAD-CAM ceramic crowns, and custom-made CAD-CAM hybrid composite crowns. Data were statistically compared using the Kruskal-Wallis test followed by the Bonferroni test, and the level of significance was set at 5%., Results: Results showed that there was a statistically significant difference among the four groups (p < .001). The highest value of fracture force was observed for the milled zirconia crown and the lowest for the prefabricated zirconia., Conclusion: The implementation of the CAD-CAM digital crown fabrication technique has the potential to address issues associated with preformed crowns in paediatric patients, particularly in terms of fracture resistance., (© 2024 BSPD, IAPD and John Wiley & Sons Ltd.)

Introduction: In this study, the effects of adding titanium dioxide nanotubes (TiO 2 ) to 3D-printed denture base resin on the mechanical and physical properties of denture bases were examined for the first time., Methods: The specimens were digitally created using 3D builder software from Microsoft Corporation through computer-aided design. In accordance with the test specifications for transverse strength, impact strength, hardness, surface roughness, and color stability, specimens were designed and printed with certain dimensions following relevant standards. TiO 2 nanotubes (diameter: 15-30 nm and length: 2-3 μm) were added to the 3D-printed denture base resin (DentaBase, Asiga, Australia) at 1.0% and 1.5% by weight. Flexural strength, impact strength (Charpy impact), hardness, surface roughness, and color stability were evaluated, and the collected data were analyzed with ANOVA followed by Tukey's post hoc test (α = 0.05). Field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDX) mapping were used to evaluate the dispersion of the nanotubes., Results: Compared with those of the control group (0.0 wt.% TiO 2 nanotubes), the average flexural, impact, and hardness values of the 1.0 and 1.5 wt.% TiO 2 nanotube reinforcement groups increased significantly. Both nanocomposite groups showed significant color changes compared to that of the pure resin, and there was a considerable reduction in the surface roughness of the nanocomposites compared to that of the control group., Conclusion: Adding TiO 2 nanotubes to 3D-printed denture base materials at 1.0 and 1.5 wt.% could enhance the mechanical and physical properties of the material, leading to better clinical performance., Clinical Significance: In terms of clinical applications, 3D-printed denture base material has been shown to be a viable substitute for traditional heat-cured materials. By combining this with nanotechnology, existing dentures could be significantly enhanced, promoting extended service life and patient satisfaction while addressing the shortcomings of the current standard materials., (© 2024 The Author(s). Journal of Esthetic and Restorative Dentistry published by Wiley Periodicals LLC.)

This study aimed to comprehensively investigate the degradation behavior of 3D printed polymethyl methacrylate (PMMA) dental materials, with a specific focus on the influential factors of temperature and moisture, by employing molecular dynamics simulations. Owing to their aesthetic properties, 3D-printed PMMA dental materials play a pivotal role in dental applications. However, understanding their degradation mechanisms, particularly in the context of temperature and moisture variations, is crucial for their long-term durability. A Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) was utilized for the molecular dynamics simulations. The simulation setup included temperature variations from 300 to 600 K and relative humidity (RH) levels ranging from 20 to 100%. Various mechanical properties and structural changes were analyzed to determine the degradation behavior. Energetic profiling during equilibration and the subsequent temperature variations were studied. The spatial distribution of the mean squared displacement, non-bond energy, Young's modulus, bending stress, and volume expansion coefficient of the particles were quantitatively analyzed, revealing temperature- and moisture-dependent trends. The study concluded that temperature and moisture significantly affected the degradation behavior of 3D-printed PMMA dental materials. Higher temperatures and increased humidity levels contribute to reduced mechanical strength and altered structural properties, emphasizing the importance of controlling environmental conditions during fabrication., (© 2024. The Author(s).)

This study investigated the effect of various storage media on the physicochemical properties of plasma-treated 3-mol% yttria-stabilized tetragonal zirconia: air, vacuum, deionized water (DIW), and plasma-activated water (PAW). Each group was divided into five subgroups based on storage periods: immediately after NTP irradiation (T0), and after 1 week (T1), 2 weeks (T2), 3 weeks (T3), and 4 weeks (T4). The control group (C) received no treatment. The storage groups were monitored weekly using various analytical techniques, including contact angle measurements, scanning electron microscopy (SEM), focused ion beam (FIB)-SEM, confocal laser scanning microscopy (CLSM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD). Our results demonstrate that plasma-treated zirconia surfaces stored in DIW retained or even increased their hydrophilicity due to the formation of hydrogen bonds and preservation of nitrogen functionalities. In contrast, surfaces stored in air exhibited significant hydrophobic recovery. FIB-SEM analysis showed no adverse internal structural changes regardless of storage medium. The roughness of the zirconia surface slightly increased after plasma treatment and was generally retained across all storage groups for 4 weeks, except for the air storage group. This study concludes that storage in DIW effectively preserves the enhanced surface properties of plasma-activated zirconia for up to 4 weeks., (© 2024. The Author(s).)

Purpose: Current denture base resins lack adequate strength and antimicrobial properties, necessitating the exploration of alternative solutions. The purpose of this study was to evaluate the effects of curcumin incorporation on the physico-mechanical properties of heat-cured denture base resin, filling a gap in the literature regarding this correlation., Methods: Heat-cured denture base resin was supplemented with increasing concentrations of curcumin (CR). Groups were designated as CR-0 (0%), CR-0.05 (0.05%), CR-0.10 (0.10%), CR-0.50 (0.50%), and CR-1 (1%), based on the increasing concentrations of curcumin incorporated into the material. Physico-mechanical properties, including flexural strength, surface roughness, fracture toughness, impact strength, and color difference, were evaluated following the testing standards. Statistical analysis involved Kruskal-Wallis ANOVA followed by Dunn's test for multiple comparisons, with significance set at P ≤ 0.05 and Bonferroni's correction applied to p-values., Results: Flexural strength peaked at 153.80 MPa in the CR-0.10 group, while surface roughness was lowest at 0.14 micrometers in the CR-0.50 group. Fracture toughness reached its highest value at 1.80 kJ/m^2 in the CR-0.05 group, and impact strength was greatest at 6.52 Joules in the CR-0.05 group. Additionally, color difference was least pronounced in the CR-0.50 group. Flexural strength, surface roughness, fracture toughness, impact strength, and color difference varied significantly among the control group and different curcumin concentrations (P < 0.05)., Conclusions: Incorporating curcumin into denture base resin alters both optical and mechanical properties. Further research is required to validate the findings and determine the optimal curcumin concentration without compromising the material efficacy., (© 2024. The Author(s).)

Background: It was aimed to investigate the effect of sandblasting and laser surface treatment on shear bond strength in composite restoration repair in vitro., Methods: A micro-hybrid composite (Filtek Z250, 3 M-ESPE, USA) was used to prepare 120 samples. The samples were subjected to a thermal cycle test 5,000 times between 5 and 55 0 C, and they were randomly divided into 12 groups (n = 10). No surface treatment was performed in Groups 1 to 4, which were designed as control groups. The surfaces of the samples in Groups 5 to 8 were sandblasted with a Cojet device, and the surfaces of the samples in Groups 9 to 12 were applied Er, Cr: YSGG laser. After the sample surfaces were divided into groups with and without acid etching, universal adhesive was applied, and the repair process was performed using Filtek Z250 or nano-filled resin composite (Filtek Ultimate, 3 M-ESPE, USA). The thermal cycle test was repeated 5,000 times between 5 and 55 0 C on all repaired samples. The repair shear bond strength of the samples was measured using a universal testing device (Shimadzu IG-IS, Kyoto, Japan). The fracture types were evaluated by optical microscopy and scanning electron microscopy (SEM). Statistical analyses of the findings were evaluated by the Kruskal Wallis test and Mann Whitney U test at 0.05 significance degree., Results: The highest mean shear bond strength values were obtained from the samples sandblasted with CoJet, followed by Er, Cr: YSGG laser, and the control group. It was determined that there was a significant difference between the mean shear bond strength values obtained from the control group and the other surface treatment groups (p < 0.05). In general, significantly higher mean shear bond strength values were obtained when the universal adhesive was applied in total-etch mode compared to the application in self-etch mode (p < 0.05). Additionally, it was determined that higher shear bond strength values were obtained with Filtek Ultimate compared to Filtek Z250 (p < 0.05)., Conclusion: Within the limitations of this study, it can be concluded that the use of universal adhesive in total-etch mode, in addition to surface treatments on the resin composite surface in the repair protocol and the use of nano-filled resin composite as repair material can increase the mean shear bond values in repair., (© 2024. The Author(s).)

New computer-aided design and computer-aided manufacturing (CAD-CAM) materials have been reported to have suitable mechanical and physical properties for endocrown restorations. However, there is a lack of literature on evaluating the retention of endocrown using these materials. This in vitro study aimed to compare the retention of endocrowns fabricated from 3 different CAD-CAM materials. Sixty human mandibular third molars were divided into 3 groups (n = 20) according to the material used: (e.max CAD, Ivoclar AG, Schaan, Liechtenstein), (HC, Shofu, Koyoto, Japan), and (Brilliant Crios, Coltene, Altstätten, Switzerland) (n = 20). Specimens were stored in distilled water at 37 °C for 1 week and subjected to 5000 thermal cycles. A universal testing machine (5500R/1123, Instron, Norwood, USA) was used to measure the tensile force. All results were statistically analyzed using one-way ANOVA (α = 0.05), and different failure modes were demonstrated. The results revealed that e. max CAD showed the highest mean tensile force value (402.35 ± 15.812) N, and the lowest mean tensile force value was for Brilliant Coris (118.90 ± 12.430) N (P < .001). It is concluded that e.max CAD endocrowns showed the highest tensile force values after thermocycling in comparison to other materials with a significant difference, which may have a promising impact on the survival of endocrown restorations., (© 2024. The Author(s).)

This study aimed to investigate adhesive shear bond strength (SBS) on an ultrafine-grained niobium alloy (UFG-Nb) that is a potential dental implant material. SBS of three adhesive systems combined with three composites to UFG-Nb was compared to corresponding SBS to Ti-6Al-4V and to zirconia. Specimens of the substrates UFG-Nb, Ti-6Al-4V and zirconia with plane surfaces were sandblasted with Al 2 O 3 , cleaned and dried. Three adhesive systems (Futurabond U, Futurabond M + , Futurabond M + DCA; all VOCO GmbH, Cuxhaven, Germany) were applied each on specimens of each substrate and light cured. One composite (BifixSE, BifixQM, GrandioSO; all VOCO GmbH) was applied and light cured resulting in 27 groups (n = 10) for all substrate-adhesive-composite-combinations. SBS was measured after 24 h of storage. To simulate aging equally prepared specimens underwent 5000 thermocycles before SBS measurement. There was no significant difference in SBS within the non-aged groups. Among the artificially aged groups, GrandioSO-groups showed a greater variance of SBS than the other composites. All significant differences of corresponding UFG-Nb-, Ti-6Al-4V- and zirconia-groups with same adhesive-composite-combination (ACC) were observed between UFG-Nb and zirconia or Ti-6Al-4V and zirconia but never between the two metallic substrates. The similarity between these materials might show in their adhesive bonding behavior. As there were no differences comparing corresponding groups prior to and after artificial aging, it can be concluded that aging does not affect SBS to UFG-Nb, Ti-6Al-4V and zirconia using the tested ACCs. Adhesive bonding of established ACCs to UFG-Nb is possible resulting in SBS comparable to those on Ti-6Al-4V and zirconia surfaces., (© 2024. The Author(s).)

Purpose: To investigate the esthetic outcomes based on the color differences in zirconia (Zr) of varying thickness, resin cement color, and types of titanium (Ti) implant surface treatments., Materials and Methods: Overall, 28 high-translucency monolithic zirconia (HTMZ) specimens were arranged into four groups based on Zr thickness: 1.0, 1.5, 2.0, and 2.5 mm (n &#61; 7 per thickness). Each group was tested using two resin cement colors (clear and opaque) in combination with six surface-treated Ti groups (n &#61; 7), including untreated titanium (UT), anodization (AN), 50-μm alumina airborne-particle abrasion followed by AN (SBAN), AN followed by 50-μm alumina airborne-particle abrasion (ANSB), 9.5% hydrofluoric acid followed by AN (HFAN), and AN followed by 9.5% hydrofluoric acid (ANHF). This created a total of 48 experimental groups, including the use of composite resin (n &#61; 7, shade A2D) for four control groups. All specimens were measured using a spectrophotometer and subsequently compared with composite resin (control) with the corresponding Zr thickness to establish color differences. A color difference of < 2.7 was considered clinically acceptable. The data obtained were statistically analyzed using ANOVA and post hoc test (P &#61; .05)., Results: Zr thickness, resin cement color, and type of Ti implant surface treatment significantly affected the observed color differences (P < .05). When using 2.5-mm HTMZ with clear resin cement on AN, UT, SBAN, HFAN, and ANSB, the mean color differences were below the clinically acceptable values, and the 95% CIs of color differences were below the clinically acceptable values for AN, UT, and SBAN groups., Conclusions: HTMZ with a minimum thickness of 2.5 mm and clear resin cement on AN, UT, and SBAN groups potentially result in acceptable color matching with 95% CIs.

Aim: The aim of the present in vitro study was to investigate the effects of different sintering procedures on the fit, color parameters, and fracture load of monolithic fixed partial prostheses (FPPs)., Materials and Methods: A metal master model was scanned and FPPs were designed. Groups were created by fabricating FPPs using four different sintering procedures (n &#61; 10): Prettau-Standard (PST); Prettau-Slow (PSL); Ice-Speed (ISP); Ice-Standard (IST). PST-PSL (Group P; N &#61; 20) and ISP-IST (Group I; N &#61; 20) were colored with different coloring liquids. The marginal and internal fit were measured using the silicone replica method. CIELAB values of the samples were measured using a spectrophotometer. Then, for each sample, the die was obtained from polymethyl methacrylate. The specimens were cemented into dies and tested in a universal testing machine for fracture load. One-way ANOVA was performed to assess the effect of the sintering procedure on the marginal and internal fit; fracture load; and ∆E00, ∆L', ∆C', and ∆H' values of the FPPs., Results: The PSL and PST groups showed significantly smaller internal and marginal fit values compared with the ISP group. Additionally, the internal fit values of the IST group were significantly higher than those of Group P. Sintering time reduction led to a decrease in ∆E00 values. Fracture load values were not statistically significantly affected by the different sintering procedures for both brands., Conclusion: Different sintering procedures did not have a clinically significant effect on fit and fracture load. Different sintering procedures were found to have an impact on the color change of monolithic zirconia restorations.

Aim: The objective of the present study was to investigate the effect of using different materials for the fabrication of implant abutments and crowns on the mechanical behavior of implant-supported single crowns after artificial aging. The materials were tested in different combinations to reveal whether using stiff or resilient materials as an abutment or a crown material might influence the fracture strength of the whole structure., Materials and Methods: A total of 40 implants (blueSKY) were restored with identical custom-made CAD/CAM abutments milled out of lithium disilicate or ceramic-reinforced polyetheretherketone (PEEK) and divided into five test groups (n &#61; 8). Forty crowns made of three different materials (zirconia, lithium disilicate, and ceramic-reinforced PEEK) were used to restore the abutments. Specimens were subjected to mechanical loading up to 1,200,000 cycles in a chewing simulator (Kausimulator) with additional thermal cycling. The surviving specimens were subjected to quasi-static loading using a universal testing machine (Z010)., Results: The PEEK abutments with zirconia crowns showed the highest median failure load (3890.5 N) while the PEEK abutments with lithium disilicate crowns exhibited the lowest (1920 N). Fracture and deformation occurred in both the crowns and abutments., Conclusion: The failure load of the restorations was influenced by the material of the abutment and crown. Restoring PEEK abutments with zirconia crowns showed a high failure load and no screw loosening.

Background: Several calcium silicate-based sealers have recently emerged in endodontics. This study aimed to compare the immediate and delayed shear bond strength between the bioceramic and calcium hydroxide-based sealers and different resin-based restorative materials., Methods: One hundred and twenty specimens with a 3-mm depth and a 3-mm diameter were prepared. They were evenly divided into two groups, the bioceramic sealer and calcium hydroxide-based sealer groups. Each primary group was subdivided into two subgroups based on the restorative material used; i.e., the flowable resin composite and resin-modified glass ionomer subgroups. Moreover, each subgroup was further divided into the restoration process's timing: either immediately post-sealing or delayed after setting the sealers for seven days. The mode of failure was assessed by stereomicroscopic examination., Results: The highest shear bond strength was found when the bioceramic sealer was used and restored with the flowable resin composite. The strengths were 8.45 (1.17) and 6.67 (1.60) megapascals (MPa) in the immediate and delayed restoration groups, respectively. In contrast, the lowest strength, 2.91 (1.22) MPa, was recorded when calcium hydroxide-based sealer was employed and restored after allowing the sealer to set completely with resin-modified glass ionomer. Notably, there were no cohesive fractures within the tested restorative materials. All observed fractures occurred within the sealer materials, at the interface of the sealer and restorative material, or in combination. Moreover, the most common failure was a mixed failure., Conclusions: When flowable resin composite was used immediately before complete setting, bioceramic sealers showed a higher bond strength than calcium hydroxide-based sealers., (© 2024. The Author(s).)

Purpose: To evaluate interfacial three-dimensional adaptation and internal voids of different flowable materials before and after cyclic fatigue in a simulated deep-margin elevation scenario., Methods: Eighty (n &#61; 80) extracted premolars were selected and two Class II cavities were prepared. The mesial one with cervical margin 1 mm above the cementum-enamel junction (CEJ) and the distal one with cervical margin 1 mm below the CEJ. After performing adhesive procedures, specimens were divided into four groups according to the employed materials for 2 mm horizontal deep-margin relocation: nanohybrid composite (Clearfil ES2, Kuraray); conventional viscosity flowable composite (Tetric Flow, Ivoclar); medium viscosity flowable composite (Majesty ES2 Low Flow, Kuraray); high viscosity flowable composite (Majesty ES2 Super Low Flow, Kuraray). All restorations were finalized by oblique layering with nanohybrid composite (Clearfil ES2, Kuraray). To reveal interfacial and internal gap progression, specimens were scanned with a micro-CT (SkyScan 1172), before and after 500,000 cycles of mechanical chewing simulation (50 N, 1 Hz). Data were imported into Mimics software after smoothing and region growing. Only the 2 mm margin relocation volumes were considered. Obtained masks were analyzed for noise removal and volume calculation. At baseline, interfacial gap progression and internal voids, expressed in mm3, were collected and statistically analyzed with two-way ANOVA (α 0.05) for the variables substrate and restorative materials followed by Tukey post-hoc test. An additional two-way ANOVA test, followed by Tukey post-hoc test, was performed to evaluate variation in interfacial gap progression after mechanical aging., Results: At baseline, the ANOVA test showed a significant difference for the variable restorative materials (p &#61; 0.01). More specifically, the Tukey post-hoc test revealed that the highly filled medium viscosity composite performed better than the conventional viscosity composite at baseline for the interfacial gap. The internal voids ANOVA test at baseline reported no significant differences for the variable tested. Analysis of variance for internal gap progression after thermocycling showed no differences for both substrate and restorative material employed., Conclusions: Highly filled medium viscosity composite performed significantly better than the conventional viscosity flowable composite for what concern baseline interfacial gaps. Artificial aging with a chewing simulator and thermocycling did not affect interfacial gap progression on enamel and dentin. The tested restorative materials performed equally after aging.

Background: The pre-polymerization temperature of resin composite restorative materials could influence their adaptation to cavity details. As a current debate is existing about the refrigeration of resin composite restorative materials, this study was designed to assess the effect of refrigeration of 3 types of resin composite restorative materials with different matrix systems on their marginal adaptation in Class II restorations., Methods: Forty-two sound maxillary molars, each with two separated Class II cavities, were used in this study. The teeth were assigned into 3 main groups (n = 14) according to the restorative /adhesive system used; an Ormocer-based composite (Admira Fusion/Futurabond M+, Voco GmbH, Cuxhaven, Germany), a methacrylate modified Ormocer-based (Ceram.X SphereTEC One/Prime&Bond Universal, Dentsply Sirona GmbH Konstanz, Germany), and a methacrylate-based (Tetric N-Ceram/Tetric N-Bond Universal, Ivoclar Vivadent AG, Schaan, Liechtenstein). Each group was then divided into 2 subgroups (n = 14) according to the gingival margin location; 1 mm above and 1 mm below the cemento-enamel junction (C.E.J). Each subgroup was further divided into 2 categories (n = 7) according to the storage temperature; stored at room temperature or stored in refrigerator at 4°- 5° C. Epoxy resin replicas were observed under scanning electron microscope (SEM) to examine the marginal gaps. A gab scoring system was used to assess the marginal adaptation of each restoration by giving scores on the basis of measurements of the maximum marginal gaps. The data obtained were statistically analyzed using the Chi-square test at a significance level of p < 0.05., Results: None of the tested groups exhibited 100% gap-free margins irrespective of margin location or storage temperature. For both storage temperatures, no statistically significant difference was observed among all tested groups either with margins located above or below C.E.J (p > 0.05). As well, there was no statistically significant difference when comparing both marginal locations for each material (p > 0.05). Regarding the effect of storage temperature, statistically significant difference was only observed between the room-temperature stored groups with margins located above C.E.J and their corresponding groups stored in refrigerator (p < 0.05)., Conclusion: The refrigeration of resin composite restorative materials prior to the restorative procedures revealed a deleterious effect on marginal adaptation of the restorations with margins located in enamel regardless the type of material used., (© 2024. The Author(s).)

The coloring process of monolithic dental zirconia caused considerable debate on the possible effects of different coloring methods. The main objective of this study was to investigate the influence of pigments in 3 multilayer 5-mol% yttria partially stabilized zirconia (5Y-PSZ) disks (Lava Esthetic A2 [Zr-AGG&#95;A2] and Bleach [Zr-AGG&#95;BL], both 3M Oral Care, and Katana STML A2 [Zr-NoAGG], Kuraray Noritake). The influence of pigment addition on the translucency parameter (TP 00 ), fracture toughness, Vickers hardness, biaxial strength, and hydrothermal stability was assessed and correlated with the microstructure and phase composition. The pigment composition and distribution were evaluated by light and fluorescence microscopy, electron probe microanalysis, and nano-scanning electron microscopy. The chemical and phase composition and aging behavior were assessed using X-ray fluorescence and X-ray diffraction, respectively, while the aging sensitivity of the pigments was evaluated using micro-Raman spectroscopy. In contrast to Zr-NoAGG, possessing a typical 5Y-PSZ microstructure, the pigment additions in both Zr-AGG&#95;A2/BL zirconia resulted in large yellow and blue fluorescent Er-, Hf-, and Al-containing agglomerates composed of small grains (0.57 µm and 0.38 µm, respectively, vs. 0.92 µm for the surrounding grains) with lower Y 2 O 3 content. Zr-AGG&#95;A2 had the lowest aging resistance, with transformation degradation occurring exclusively within the pigment agglomerates. All zirconia grades had a high Y 2 O 3 content (4.2%-5.7 mol%) tetragonal ZrO 2 phase and a high (42%-55 wt%) cubic ZrO 2 phase content. Although no statistical differences were measured for hardness and toughness, Zr-NoAGG had a significantly higher TP 00 , higher flexural strength, and lower mechanical reliability compared to both Zr-AGG&#95;A2/BL zirconia. The rare-earth oxide-containing zirconia agglomerates that were added as pigments to the multilayered monolithic Zr-AGG&#95;A2/BL zirconia are the cause for their lower optical and mechanical properties and reduced aging resistance., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: The demand for esthetics has increased in today's world and most parents prefer to preserve their children's primary anterior teeth until their natural exfoliation. However, an intracanal post is required to provide retention for reconstruction of severely damaged anterior teeth due to caries or trauma. Various materials and methods may be used for the fabrication of intracanal posts. This study assessed the fracture strength and fracture mode of primary canine teeth reconstructed with prefabricated and customized polyethylene and glass fiber posts., Materials and Methods: This in vitro study evaluated 60 extracted primary canine teeth in four groups (n = 15). After pulpectomy and post space preparation with 4 mm depth, composite resin post, prefabricated glass fiber post (Whitepost), customized glass fiber post (Interlig), or customized polyethylene fiber post (Ribbond) were placed in the root canals to provide retention, and the tooth crown was restored with bulk-fill composite resin. The fracture strength was then measured in a universal testing machine. The fracture mode was also evaluated visually., Results: The mean fracture strength was 22.45 ± 5.06, 33.10 ± 8.5, 30.20 ± 7.33, and 32.61 ± 5.73 N/mm 2 in the composite resin post, Whitepost, Interlig, and Ribbond groups, respectively. The fracture strength was significantly lower in the composite group than in the remaining three groups (p = 0.000). No other significant differences were found (p > 0.05). Also, no significant difference was observed among the study groups in the fracture mode (p = 0.241)., Conclusion: The composite resin post yielded a significantly lower fracture strength than the prefabricated and customized glass and polyethylene fiber posts, but the fracture mode was not significantly different among the four groups., (© 2024 The Author(s). Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

The study aimed to investigate the influence of H 2 O 2 -based and H 2 O 2 -free in-office bleaching on the surface and mechanical attributes of CAD/CAM composite blocks. CAD/CAM composite blocks from five different composite materials (CC1, CC2, CC3, CC4, and CC5) were randomly divided into two groups according to bleaching application (H 2 O 2 -based and H 2 O 2 -free). The surface topography, morphology, nanohardness, elastic modulus, flexural strength, and fracture toughness were measured. A paired and unpaired sample t-tests gauged the effect of pre- and post-bleaching on the substrates. The estimated mean differences (before-after bleaching) suggested an increase in surface roughness for two materials CC2 and CC4, and a significant decrease in nanohardness for material CC4 and in elastic modulus for materials CC2 and CC4 with H 2 O 2 -based bleaching, whereas H 2 O 2 -free bleaching resulted in changes compatible with no change in these properties. Flexural strength and fracture toughness showed no evidence of changes, irrespective of the bleaching gel used. Scanning electron microscopic analysis revealed erosive effects and micropore formation due to H 2 O 2 -based bleaching. H 2 O 2 -based bleaching deteriorates the surface of CAD/CAM composite materials while H 2 O 2 -free bleaching gel had an insignificant effect on both surface and bulk properties. The clinician should carefully evaluate the potential effects of H 2 O 2 -based bleaching on the surface properties of CAD/CAM composites., (© 2024 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

Objective: To assess the prediction accuracy of recent optical and numerical models for the spectral reflectance and color of monolithic samples of dental materials with different thicknesses., Methods: Samples of dental resin composites of Aura Easy Flow (Ae1, Ae3 and Ae4 shades) and Estelite Universal Flow Super Low (A1, A2, A3, A3.5, A4 and A5 shades) with thicknesses between 0.3 and 1.8 mm, as well as Estelite Universal Flow Medium (A2, A3, OA2 and OA3 shades) with thicknesses between 0.4 and 2.0 mm, were used. Spectral reflectance and transmittance factors of all samples were measured using a X-Rite Color i7 spectrophotometer. Four analytical optical models (2 two-flux models and 2 four-flux models) and two numerical models (PCA-based and L*a*b*-based) were implemented to predict spectral reflectance of all samples and then convert them into CIE-L*a*b* color coordinates (D65 illuminant, 2°Observer). The CIEDE2000 total color difference formula (ΔE 00 ) between predicted and measured colors, and the corresponding 50:50% acceptability and perceptibility thresholds (AT 00 and PT 00 ) were used for performance assessment., Results: The best performing optical model was the four-flux model RTE-4F-RT, with an average ΔE 00 = 0.72 over all samples, 94.87% of the differences below AT 00 and 65.38% below PT 00 . The best performing numerical model was L*a*b*-PCHIP (interpolation mode), with an average ΔE 00 = 0.48, and 100% and 79.69% of the differences below AT 00 and PT 00 , respectively., Significance: Both optical and numerical models offer comparable color prediction accuracy, offering flexibility in model choice. These results help guide decision-making on prediction methods by clarifying their strengths and limitations., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Owing to its desirable ability to fabricate complex shapes, three-dimensional printing is preferred over casting for manufacturing dentures. Furthermore, titanium is widely used in dental implants and dentures because of its high corrosion resistance, biocompatibility, strength, and low density. In this study, we aimed to develop a new metal denture material from three-dimensional-printed (3DP) to achieve lighter weight and greater strength than those of PMMA dentures. Hollow (3DP-H) structure and solid (3DP-S) structure titanium plate specimens of 0.5, 1.0, and 3.0 mm in thickness were used. Casted Ti, casted Co-Cr, and PMMA plates were fabricated for comparison. Elastic modulus, density, thermal conductivity, hardness, and proof stress of the specimens were measured and plotted on a radar chart to enable multifaceted evaluation. The results indicated that the density of the 3DP-H plates reduced by 28-36% compared with those of 3DP-S and cast Ti plates. The weight of the metal-denture-equivalent section of the 0.5-mm-thick 3DP-H titanium-plated denture reduced to two-thirds that of the 2.0-mm-thick PMMA denture. The proof stress of the 0.5-mm-thick 3DP-H plate increased to about 3 times that of the 2.0-mm-thick PMMA plate. The total value of the 0.5-mm-thick 3DP-H titanium plates was higher than it of the 1.0-mm-thick PMMA plates. This study suggests that it is possible to produce 3DP-H titanium plate dentures exhibiting not only extremely lightweight compared to conventional PMMA dentures but also sufficient strength., (© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

The research exploiting the ability of dental materials to induce or prevent secondary caries (SC) development still seems inconclusive. Controlling bacterial adhesion by releasing bacteriostatic ions and improving the surface structure has been suggested to reduce the occurrence of SC. This paper analyses the impact of five distinctively composed dental materials on cariogenic biofilm formation. Forty-five specimens of three composites (CeramX Spectra ST, Admira Fusion, Beautifil II) and two glass-ionomers (Fuji II LC, Caredyne Restore), respectively, were incubated in bacterial suspension composed of Streptococcus mutans, Lactobacillus acidophilus, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus salivarius at pH 7.0 and 5.5. Coverslips were used as a control. Adhered bacteria were collected after 2, 4, 6, 12, 24, and 48 h and analyzed using quantitative polymerase chain reaction (qPCR). Fluoride leakage was measured at each collection. The specimens' surface topography was assessed using interferometry. In the present study, surface roughness seemed to have a partial role in bacterial adhesion and biofilm formation, together with chemical composition of the materials tested. Despite differences in fluoride leakage, biofilm accumulation was similar across materials, but the number of adhered bacteria differed significantly. A release of other ions may also affect adhesion. These variations suggest that certain materials may be more prone to initiating secondary caries., (© 2024. The Author(s).)

Aim: The aim of this study is to evaluate the discolouration resistance of attachments made of composites having different physical properties, filler ratios and viscosity through the simulated environment and conditions., Materials and Methods: Seventy-two extracted human teeth were aligned to simulate upper and lower dental arches. The attachments were prepared according to the guides determined by ClearCorrect. Three different composite groups were used for attachments preparation: Aligner Connect, G-Aenial Universal Injectable, and Tetric Prime and Tetric Evoflow combination. Dental models and aligners were kept in artificial saliva throughout the experiment of 96 weeks. The aligners were also subjected to 2308 thermal cycles and insertion and removing procedures 840 times for each period of 12 weeks. Afterwards, the models were kept in coffee and red wine solutions. Colour measurements were made with Vita Easy Shade 4.0 at 12th, 24th, 48th and 96th simulated weeks., Results: No significant difference in discolouration was observed during thermal cycle application of 12th and 24th week experimental periods. In the later periods, discolouration was observed in the composite materials, and G-Aenial Universal Injectable was less coloured than the other samples. The composite samples were more coloured in proportion to their residence time. The G-Aenial Universal Injectable was more affected by wine solution, and Tetric Prime and Tetric Evoflow combination were more affected by coffee solution., Conclusions: Viscosity, resin matrix content and nature of inorganic filler particles of the composite materials significantly affect the colour changing properties of them due to the long-term ageing and exposure to colouring agents., (© 2024 The Authors. Orthodontics & Craniofacial Research published by John Wiley & Sons Ltd.)

Objectives: We evaluated the mechanical properties of zirconia restorations produced via additive manufacturing (AM) and the crown accuracy of zirconia crowns., Methods: Zirconia disks, bars, and crowns were manufactured via subtractive (CNC group) and additive manufacturing (AM group) techniques. Disk-shaped specimens in each group were autoclaved at 134 °C and 216 kPa for 5, 10, and 24 h. The phases of the specimens were analyzed using an X-ray diffractometer. The flexural strengths were measured via biaxial flexural tests. The morphologies were examined using a scanning electron microscope. The correlation between the m-phase fraction and biaxial flexural strength by autoclave time in each group was analyzed via linear mixed model and Pearson's correlation analysis. For each group, crown specimens were used to assess the marginal and internal gaps using the replica technique. Buccolingual and mesiodistal cross-sections were measured, and a repeated measures one-way ANOVA was performed., Results: Linear mixed model analysis indicated that for both groups, with an increase in the autoclave time, the flexural strength decreased, whereas the m-phase fraction increased. Pearson's correlation analysis revealed no correlation between the m-phase fraction and flexural strength for either group. A repeated measures one-way ANOVA was conducted on instrumented sections (buccal, lingual, mesial, and distal), revealing that the marginal and internal gaps of AM-produced zirconia crowns were less accurate than those of CNC-produced zirconia crowns., Significance: These findings suggest that additively produced zirconia restorations have mechanical properties comparable to those of conventionally produced ceramics and may be suitable for clinical applications., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study evaluated the changes in surface properties of three resin-based restorative materials after two laser-assisted, in-office tooth bleaching protocols using erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) or diode (980 nm) lasers. A nanohybrid composite (Enamel Plus HRi), a Bis-GMA-free composite (Enamel Plus HRi Bio Function), and a resin-matrix CAD-CAM ceramic (Shofu Block HC) were tested. Forty specimens for each material were prepared and divided into four groups (n = 10/group). The control specimens did not undergo any bleaching treatment, whereas group 2 received bleaching with 40% hydrogen peroxide (H 2 O 2 ), while groups 3 and 4 underwent the same bleaching procedure with the use of diode (980 nm) or Er,Cr:YSGG lasers, respectively. Surface microhardness and roughness measurements were conducted using a Vickers tester and an optical profilometer. Microhardness was lower in bleached specimens, with the nanohybrid composite exhibiting the largest difference from the no bleaching group. For the Bis-GMA-free composite the microhardness difference between no bleaching and laser-assisted bleaching were smaller than seen for the conventional bleaching technique. Surface roughness was higher in bleached specimens, with nanohybrid composite showing the largest differences from the control specimens. The examined laser-assisted tooth bleaching protocols were found not to impact surface microhardness and roughness of the tested resin-based specimens and they are deemed suitable for clinical use., (© 2024 The Author(s). European Journal of Oral Sciences published by John Wiley & Sons Ltd on behalf of Scandinavian Division of the International Association for Dental Research.)

Objectives: To evaluate the clinical performance of direct restorations for pit-and-fissure caries in molars using stamp combined with single-shade composite resin (S/SCR) technique, and assess the effect of the number of stamp pressing on the trueness of S/SCR technique., Methods: Twenty molars of fifteen patients with pit-and-fissure caries but with an intact or micro-cavitated occlusal morphology were restored using S/SCR technique and were randomly divided into single pressing group (n = 10) and double pressing group (n = 10). Intraoral scans were obtained before treatment (scan 1), after filling (scan 2) and after polishing (scan 3). Deviation distribution maps of pairwise fitting were created including comparison 1 (scan1/scan 2), comparison 2 (scan1/scan 3), and comparison 3 (scan2/scan 3) using Geomagic Control X software. Root mean square (RMS) values were calculated to evaluate the trueness of restorations. Clinical performances including esthetic, functional, and biological properties of all restorations were evaluated according to FDI criteria after a 12-month follow-up. Analysis of variance, independent-samples T test and Wilcoxon rank-sum test were used for statistical analysis (α=0.05)., Results: RMS values for comparison 1, comparison 2, and comparison 3 were 0.1243 ± 0.0151, 0.0966 ± 0.0136, and 0.0605 ± 0.0137 mm in single pressing group, while 0.0831 ± 0.0140, 0.0741 ± 0.0107, and 0.0475 ± 0.0099 mm in double pressing group, respectively. RMS value of single pressing group was higher than that of double pressing group in the same comparison (p ≤ 0.001). No statistically significant differences were observed between the two groups regarding esthetic, functional and biological properties (p > 0.05). For all properties, all restorations scored within 3, with over 80% scoring 1., Conclusion: S/SCR technique presents satisfying clinical performances for pit-and-fissure caries in molars after a 12-month follow-up. Besides, double pressing can improve the trueness of restorations compared to single pressing., Clinical Significance: S/SCR technique is efficient in direct composite resin restoration for pit-and-fissure caries, with satisfying esthetic, functional and biological properties after a 12-month follow-up. Significantly, double pressing improves the trueness of S/SCR technique, reducing the need for occlusion adjustment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: To compare the interfacial fracture toughness (IFT) with or without aging, of four different classes of CAD-CAM ceramic and composite materials bonded with self-adhesive resin cement to titanium alloy characteristic of implant abutments., Methods: High translucent zirconia (Katana; KAT), lithium disilicate-based glass-ceramic (IPS. emax.CAD; EMX), polymer-infiltrated ceramic network material (PICN) (Vita Enamic; ENA), and dispersed filler composite (Cerasmart 270; CER) were cut into equilateral triangular prisms and bonded to titanium prisms with identical dimensions using Panavia SA Cement Universal. The surfaces were pretreated following the manufacturers' recommendations and developed interfacial area ratio (Sdr) of the pretreated surfaces was measured. IFT was determined using the Notchless Triangular Prism test in a water bath at 36 °C before and after thermocycling (10,000 cycles) (n = 40 samples/material)., Results: IFT of the materials ranged from 0.80 ± 0.25 to 1.10 ± 0.21 MPa.m 1/2 before thermocycling and from 0.71 ± 0.24 to 1.02 ± 0.25 MPa.m 1/2 after thermocycling. There was a statistical difference between IFT of CER and the two top performers in each scenario: KAT and EMX before aging, and KAT and ENA after aging. Thermocycling significantly decreased IFT of EMX. The Weibull modulus of IFT was similar for all materials and remained so after thermocycling. Sdr measurements revealed that ENA (7.60)>Ti (4.97)>CER (2.85)>KAT (1.09)=EMX (0.96)., Significance: Dispersed filler CAD-CAM composite showed lower performance than the other materials. Aging only affected IFT of Li-Si glass-ceramic, whereas zirconia and PICN performed equally well, probably due to their chemical bonding potential and surface roughness respectively., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objectives: The objective of this review was to assess clinical trials that have examined the materials, design, and bonding of ceramic cantilevered resin-bonded fixed dental prostheses (RBFDPs) as a potential option for replacing missing anterior teeth. The evaluation primarily focuses on the rate of restoration failure and clinical complications., Materials and Methods: A thorough search of databases including PubMed/MEDLINE, Scopus, and the Cochrane Library, was conducted. The most recent search was performed in October 2023. Clinical studies that compared ceramic cantilevered RBFDPs with double retainers or cantilevered RBFDPs using different ceramic materials or bonding systems were included. The outcome measures considered were restoration failure and complication rates., Results: Twelve studies met the eligibility criteria. The pooled data showed a statistically significant decrease in complication events when using cantilever designs compared with double retainer designs (p < 0.05); however, there were no differences found between the two designs in terms of restoration failure. The complication and failure rate of cantilever RBFDPs did not show a statistically significant difference with or without ceramic primer application before luting with phosphate monomer-containing luting resin (p > 0.05)., Conclusions: Ceramic cantilevered RBFDPs have lower complication rates compared with those with double retainers. The use of a ceramic primer prior to luting composite resin for ceramic cantilevered RBFDPs decreases the occurrence of complications and failures, although this effect was not statistically significant. Additional research is required to confirm these findings. Glass ceramic cantilever RBFDPs showed a decrease in success after 6 years, requiring ongoing monitoring, but both zirconia and glass-infiltrated alumina cantilever RBFDPs have demonstrated durability with excellent long-term success and survival rates for up to 10 and 15 years., Clinical Significance: Cantilever ceramic RBFDPs in the anterior region are a less invasive and valuable treatment option, providing good esthetic results., (© 2024 Wiley Periodicals LLC.)

Purpose: This study was designed to investigate the effect of post space conditioning with different solutions on the bond strength of glass FRC posts and evaluate the mode of resin failure., Methods: Sixty extracted human single rooted teeth were root filled using a resin sealer and suitable gutta-percha cones. Post spaces were prepared, and the teeth randomly allocated into 5 groups according to their irrigation regimens which included the following solutions: 17 % EDTA, 2 % CHX, 3 % NaOCl, 10 % ascorbic acid and QMix solutions. Post spaces were irrigated with 5 ml of the solution for 15 s and subsequently washed with distilled water and dried with paper points. Glass FRC posts were cemented into their spaces using a self-adhesive resin cement. The specimens were mounted in plexiglass molds using autopolymerizing acrylic resin. A universal testing machine was used to measure post retention at a crosshead speed of 2 mm/min. The results were analyzed by one-way ANOVA followed by Tukey HSD test (α = 0.05). Dislodged posts and post spaces were examined microscopically to evaluate retention failure., Results: The Ascorbic acid group exhibited the highest mean retentive strength value at 229 N, followed by QMix at 198 N, NaOCl at 186 N, CHX at 170 N, and EDTA at 124 N. The mean value of the ascorbic acid group was significantly higher than EDTA group, p = 0.012. The failure category was primarily mixed., Conclusions: Rinsing post spaces with ascorbic acid exhibited significantly superior bond strength. The failure mode was mixed., Clinical Significance: Irrigating post spaces with ascorbic acid solution before luting FRC posts significantly improves their bond strength compared to irrigation with EDTA solution. Irrigation with QMix solution produced the second highest retentive strength but showed no statistical significance when compared to using ascorbic acid, NaOCl, CHX, or EDTA solutions., Competing Interests: Declaration of competing interest The authors have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript, (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: Evaluation of biaxial flexural strength (BFS) of nanoglass (NG) and multiwalled carbon nanotubes (MWCNTs) reinforced 3D-printed denture base resins and their shear bond strength (SBS) to 3D-printed and acrylic denture teeth., Methods: Silanized NG and MWCNTs were added to 3D-printed denture base resin to obtain four groups: Control, 0.25 wt% NG, 0.25 wt% MWCNTs, and a combination group with 0.25 wt% of both fillers. All specimens were tested before and after 600 cycles of thermal aging. BFS (n = 88) was tested using disk-shaped specimens (12 ×2 mm) centralized on an O ring in a universal testing machine. Weibull analysis was conducted to assess predictability of failure. SBS (n = 176) was tested for acrylic and 3D-printed denture teeth attached to bar-shaped specimens in a universal testing machine followed by failure mode analysis using stereomicroscope. Two and three-way ANOVA tests followed by Tukey post hoc test were conducted for BFS and SBS. Kruskal-Wallis test compared percent change among groups with subsequent Dunn post hoc test with Bonferroni correction (α = 0.05)., Results: BFS was affected significantly by filler content (P < 0.001) and thermal cycling (P < 0.001), with thermal cycling displaying the uppermost effect (Ƞp 2 =0.551). A significant interaction between filler content, thermal cycling, and teeth type was displayed by SBS results (P < 0.001, F=10.340, Ƞp 2 =0.162). The highest BFS values belonged to 0.25 % MWCNTs while the highest SBS to printed teeth was displayed by the combination., Significance: The combination group displayed higher BFS and SBS to printed teeth compared to control which allows 3D-printed materials to have a long-term clinical success., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: To evaluate the postoperative sensitivity (POS), as well as the clinical performance of posterior restorations using a new chemically-cured bulk-fill composite (Stela Automix and Stela Capsule, SDI) comparing with a light-cured bulk-fill composite after 6 months., Methods: Fifty-five participants with at least three posterior teeth needing restoration were recruited. A total of 165 restorations were performed on Class I or Class II cavities. After the application of Stela primer, the chemically-cured composite (Stela Automix or Stela Capsule) was inserted. For the light-cured composite group, a universal adhesive (Scotchbond Universal) was applied with a bulk-fill composite (Filtek One). Participants were evaluated for spontaneous and stimulated POS in the baseline, after 48 h, 7 days, and 6 months. Additionally, each restoration was assessed using the updated version of FDI criteria after 6 months. The differences in the proportions of the groups were compared by Cochran test statistics (α = 0.05)., Results: Both chemically-cured composites showed a lower risk of POS compared to the light-cured composite at baseline and up to 48 h (p < 0.04). A significantly lower surface luster and texture was observed for the Stela Capsule composite compared to the light-cured bulk-fill composite (baseline and 6 months; p = 0.03). A significant color mismatch was observed for the light-cured bulk-fill composite compared to the chemically-cured composites (baseline and 6 months; p = 0.03). No significant differences were observed in any other item evaluations (p > 0.05)., Conclusion: Chemically-cured composites exhibit lower postoperative sensitivity and less color mismatch compared to a light-cured bulk-fill composite after 6 months of clinical service., Clinical Significance: The chemically-cured composites appear to be an appealing option for restoring posterior teeth, as they exhibit lower postoperative sensitivity compared to a light-cured bulk-fill composite, both at baseline and up to 48 h, and less color mismatch., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: The aim of the present study was to evaluate the influence of multidirectional brushing on the surface roughness, morphology, and bonding interface of resin-repaired CAD-CAM ceramic and composite restorations., Materials and Methods: Twelve (N = 12) blocks (4 mm × 4 mm × 2 mm for parallel axis; 5 mm × 4 mm × 2 mm for perpendicular axis) of lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar AG) and CAD-CAM resin composite (Tetric CAD, Ivoclar AG) were obtained and repaired with direct resin composite (Clearfil AP-X, Kuraray). An abrasive slurry was prepared and the brushing was performed according to each restorative material and axis of brushing (n = 6; perpendicular to repair interface and parallel to repair interface) during 3,650 cycles (240 strokes per minute) to simulate 3 years of brushing. The surface roughness (Ra) and the profile variation for each material (restoration and direct repair resin composite) were measured at the baseline condition and after brushing, and the mean roughness and presence of steps at the repair interface were evaluated through factorial analysis of Variance (ANOVA). Scanning Electron Microscopy (SEM) images were taken to evaluate the surface topography of the repaired materials after brushing., Results: The mean roughness of the repaired CAD-CAM restorations was affected by the brushing (P < .05), mainly when evaluating the repair material and the interface (P < .05), while the restorative CAD-CAM materials presented more stable values. The profile evaluation showed higher steps at the interface when repairing lithium disilicate than for CAD-CAM resin composite., Conclusion: Repaired CAD-CAM restorations were susceptible to wear after brushing simulation. The surface roughness of the direct resin composite was the most affected leading to step development at the interface, particularly in the repaired lithium disilicate samples. Cinical maintenance recalls and polishing protocols must be considered to enhance the longevity of such restorations., Competing Interests: Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: To systematically compile data on the degree of conversion (DC) for bulk-fill composites using a network meta-analysis., Methods: A systematic search for in vitro studies of DC of bulk-fill composites was performed in PubMed, Web of Science, Scopus, and Open Grey. Risk of bias within studies and due to missing evidence was assessed using the Joanna Briggs Institute scoring system and ROB-MEN tool, respectively. The primary outcome was the DC of bulk-fill composites. Surface Under the Cumulative Ranking curve (SUCRA) was used to rank relative performance. Inconsistencies in the model were investigated to ensure its validity and the level of confidence in the network meta-analysis (CINeMA) was assessed., Results: A total of 28 studies were included in the quantitative analysis. The average DC values (%) for 0-h/top, 0-h/bottom, 24-h/top, and 24-h/bottom were 59.09, 57.14, 66.73, and 63.87, respectively. According to their SUCRA ranking, the best-performing composites were: SonicFill, Venus Bulk Fill, and SDR (0-h/top), Reveal HD, i-Flow Bulk Fill, and Venus Bulk- Fill (0-h/bottom), Venus Bulk Fill, SDR, and QuiXfil (24-h/top), and Venus Bulk Fill, Aura Bulk Fill, and i-Flow Bulk Fill (24-h/bottom). Incoherence between direct and indirect evidence was identified as the most significant factor affecting confidence., Conclusions: DC values of bulk-fill composites were within the range commonly reported for previous generations of "conventional" composites, with flowable composites tending to perform better than sculptable composites. High variability in DC data was observed, which may be attributed to incompletely understood methodological differences., Clinical Significance: DC is a fundamental parameter that influences multiple mechanical and biological properties of resin composites and is particularly relevant for the group of bulk-fill composites that are designed for use in thick layers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Statement of Problem: The outcome of photopolymerized 3-dimensional (3D) printing is influenced by the methods used for postprinting cleaning, yet information on postprinting cleaning is sparse., Purpose: The purpose of this in vitro study was to assess the cleaning efficiency and surface and mechanical properties of 3D printed resin according to postprinting cleaning methods., Material and Methods: Specimens were fabricated from a 3D model using resin materials (NextDent C&B MFH and DIOnavi-P. MAX) and were tested for postprinting cleaning methods for 5 minutes with isopropyl alcohol, isopropyl alcohol + ultrasonic, ethyl alcohol, ethyl alcohol + ultrasonic, and ultrasonic alone. Postpolymerization was followed for 5 minutes. The cleaning efficiency, microcomputed tomography (µCT), surface roughness, Vickers hardness, and flexural strength of the specimens were evaluated. The 1-way ANOVA test was performed after considering normality. A post hoc analysis with Bonferroni was also performed (α=.008 or.005)., Results: Ultrasonic in addition to cleaning solutions significantly improved the cleaning efficiency in NextDent C&B MFH specimens (P<.005), whereas ultrasonic did not affect the efficiency in DIOnavi-P. MAX specimens. No significant differences were found in surface roughness by postprinting cleaning methods in either NextDent C&B MFH or DIOnavi-P. MAX (P>.005). No significant changes in surface hardness were observed by postprinting cleaning methods (P>.008). In the NextDent C&B MFH, ethyl alcohol + ultrasonic significantly decreased the flexural strength (P<.005). There were no significant differences in the flexural strength in the DIOnavi-P. MAX (P>.005)., Conclusions: Ethyl alcohol was comparable with isopropyl alcohol for use as a postprinting cleaning solution for both NextDent C&B MFH and DIOnavi-P. MAX. The addition of ultrasonic to cleaning solutions should be applied with caution. These findings suggest that different postprinting cleaning methods can be recommended depending on the 3D printed resin materials., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: The fluorescence-aided identification technique (FIT) is based on the fluorescence properties of dental materials, specifically the intensity of their fluorescence compared to the autofluorescence of hard dental substances; this creates a perceived contrast between dental material and tooth. However, no studies to date have determined the extent to which the fluorescence intensity of tooth-colored dental materials must differ from that of natural autofluorescence to ensure reliable visual detection. The aim of this study was therefore to determine, for the first time, how pronounced the difference between fluorescence intensity and autofluorescence must be to reliably identify tooth-colored material., Methods: Ten dentists assessed six different resin-based composite (RBC) samples of varying fluorescence intensity placed in the cavities of ten extracted teeth under standardized fluorescence-exciting illumination. The outcome variable was fluorescence perceptibility. Their assessments of the outcome variable were compared with measurements of the fluorescence intensities of the RBCs and the surrounding dental hard tissues, which were expressed as a fluorescence intensity ratio. Demographic data of the participants, including age, gender, and professional experience, were also recorded., Results: No significant differences were found for visual fluorescence perceptibility in relation to the explanatory variables of gender (p = 0.14), age (p = 0.13), and professional experience (p = 0.34). In contrast, the fluorescence intensity ratio was significantly different (p < 0.0001)., Significance: For both clinicians and manufacturers, fluorescence intensity levels are important when selecting or developing FIT-compatible materials. Our results suggest that the fluorescence intensity levels of dental materials should be no more than 75% and no less than 200% of tooth natural autofluorescence to ensure reliable detection of tooth-colored materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To evaluate the effect of different ratios of Bis-EMA/Bis-GMA resin mixtures on the inherent viscosity and curing-related properties: including degree of cure (DC%), shrinkage strain, Knoop micro-hardness (KH) and flexural strength of resin-impregnated fiber-bundles., Methods: Bis-EMA/Bis-GMA monomers were mixed (by weight) in the following ratios: M1 = 30 %/70 %, M2 = 50 %/50 %, M3 = 70 %/30 %, and M4 = 100 %/0 %. Standard measurements were made of refractive index, viscosity, degree of conversion, shrinkage strain and Knoop hardness (KHN). For 60 % glass fiber-bundles impregnated with 40 % resin, three-point bending test for flexural strength and shrinkage strain were measured. Data were analyzed by One-way ANOVA and Bonferroni post-hoc tests (α = 0.05)., Results: For resin mixtures, increasing Bis-EMA proportion decreased refractive index (p < 0.05), and viscosity (p < 0.05), and increased monomer conversion (DC%), shrinkage strain and KHN (p < 0.05). DC% increased after 1 h for all resin mixtures. The shrinkage strain and flexural strength of resin-impregnated fiber-bundles reduced with increased Bis-EMA., Significance: Monomeric mixtures with highest amounts of Bis-EMA showed enhancement in several clinically-relevant properties and polymerization of respective resin-impregnated glass fibers. This makes them potential candidates for impregnating glass fibers in fiber-reinforced restorations., Competing Interests: Declaration of competing interest This is to confirm there are no interests to declare regarding the above titled manuscript., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: To evaluate the influence of the tooth shade, type of resin composite and cavity configuration on the color adjustment of single-shade and group shade resin composites., Methods: Class I and V cavities were prepared in artificial acrylic mandibular right molars with different shades - A1, A2, A3, A3.5 and A4. Three single-shade (OMN, UNI, CHA) and two group shade (FIL, HAR) resin composites were evaluated. Seventy-five observers, including dentists, dental students and laypersons (n = 25), participated in the study. A psychophysical experiment based on visual assessments of the color matching between each tooth and each restoration was ranked from 0 (excellent match) to 4 (huge mismatch), and mean frequencies (%) were calculated. Visual color differences among composite materials and tooth shades were statistically tested (P < 0.05)., Results: The results showed highest percentages of unacceptable color mismatches for class V compared to class I restorations, especially for more chromatic tooth shades (A3.5 and A4). The percentage of ratings of acceptability was higher for laypersons group. For class V, OMN presented significant difference only from UNI in tooth shades A1, A2, A3 and A4. However, for class I, OMN presented significant differences with CHA for A1, A2 and A4, and with HAR and FIL for A1., Conclusions: Class I resin composite restorations exhibit superior color matching than Class V, with lighter and low chroma tooth shades demonstrating better color adjustment. The color matching of both cavity configurations is comparable for single and group shade resin composites., Clinical Significance: Cavity configuration and tooth shade may impact color matching of single and group shade resin composites. This study demonstrates superior color matching in class I configurations over class V for both single and group shade resin composites. Additionally, restorations placed in teeth with lighter shades exhibit more favorable color adjustment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Purpose: To evaluate the effect of polishing and denture cleansers on the surface roughness (R a ) of new-generation denture base materials that are additively, subtractively, and conventionally fabricated, while also assessing their color change after cleansing., Material and Methods: One hundred and fifty disk-shaped specimens (Ø10 × 2 mm) were prepared from five denture base materials (one subtractively manufactured nanographene-reinforced prepolymerized polymethylmethacrylate (PMMA) (SM-GC), one subtractively manufactured prepolymerized PMMA (SM-PM), two additively manufactured denture base resins (AM-DT and AM-ND), and one heat-polymerized PMMA (CV) (n = 30). The R a of the specimens was measured before and after conventional laboratory polishing, while color coordinates were measured after polishing. Specimens were then divided into three subgroups based on the denture cleanser: distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet (n = 10). The R a and color coordinates were remeasured after nine cleansing cycles over a period of 20 days. The CIEDE2000 formula was used to calculate the color differences (ΔE 00 ). Two-way analysis of variance (ANOVA) was used to analyze the R a values before (n = 30) and after (n = 10) cleansing, while repeated measures ANOVA was used to analyze the R a of material-time point pairs within each denture cleanser (n = 10). ΔE 00 data after denture cleansing was also analyzed by using two-way ANOVA (n = 10) (α = 0.05)., Results: Before polishing, R a varied significantly among the materials. SM-GC and SM-PM had the lowest and AM-ND the highest R a values (P < 0.001). Polishing significantly reduced R a of all materials (P < 0.001), and after polishing, R a differences among materials were nonsignificant (P ≥ 0.072). Regardless of the denture cleanser, the R a of AM-DT, AM-ND, and CV was the highest before polishing when different time points were considered (P < 0.001). After cleansing, AM-ND had the highest R a of all the materials, regardless of the cleanser (P ≤ 0.017). AM-DT had higher R a than SM-PM when distilled water (P = 0.040) and higher R a than SM-GC, SM-PM, and CV when NaOCl was used (P < 0.001). The type of cleanser significantly influenced the R a of AM-DT, AM-ND, and CV. For AM-DT, NaOCl led to the highest R a and the tablet led to the lowest R a (P ≤ 0.042), while for AM-ND, distilled water led to the lowest R a (P ≤ 0.024). For CV, the tablet led to lower R a than distilled water (P = 0.009). Color change varied among the materials. When distilled water was used, SM-GC had higher ΔE 00 than SM-PM and AM-DT (P ≤ 0.034). When NaOCl was used, AM-ND had higher ΔE 00 than SM-GC, SM-PM, and AM-DT, while CV and SM-GC had higher ΔE 00 than SM-PM and AM-DT (P ≤ 0.039). Finally, when the tablet was used, AM-ND and CV had the highest ΔE 00 , while AM-DT had lower ΔE 00 than SM-GC (P ≤ 0.015)., Conclusions: The tested materials had unacceptable surface roughness (>0.2 μm) before polishing. Roughness decreased significantly after polishing (<0.2 μm). Denture cleansers did not significantly affect the surface roughness of the materials, and roughness remained clinically acceptable after cleansing (<0.2 μm). Considering previously reported color thresholds, AM-ND and CV had unacceptable color change regardless of the denture cleanser, and the effervescent tablet led to perceptible, but acceptable color change for SM-GC, SM-PM, and AM-DT., (© 2023 The Authors. Journal of Prosthodontics published by Wiley Periodicals LLC on behalf of American College of Prosthodontists.)

Statement of Problem: Additive manufacturing (AM) technology is emerging as an innovative approach in the dental field. In recent years, manufacturers have introduced 3-dimensionally printed composite resins (3D-CRs) that are specifically designed for the AM of definitive prostheses; however, the mechanical and surface properties of these materials require investigation., Purpose: The purpose of this in vitro study was to assess and compare the mechanical and surface properties of 2 commercially available 3D-CRs for definitive restoration after artificial aging., Material and Methods: Saremco print Crowntec; Saremco Dental AG and Varseo Smile Crown Plus; Bego GmbH were printed with a layer thickness of 50 µm at a 90-degree angle. A total of 20 bar-shaped specimens (25×2×2 mm) were produced from each material to measure the flexural strength (σf) and elastic modulus (E) using a 3-point bend test, and 5 disk-shaped specimens (Ø15×3 mm) from each material were used to measure the surface microhardness using a microhardness test. Half of the specimens were tested under dry conditions, while the other half were immersed in distilled water for 30 days. Five disk-shaped specimens (Ø15×3 mm) from each material were used to evaluate surface roughness before and after undergoing toothbrushing simulations. Additionally, 5 disk-shaped specimens (Ø15×1 mm) were used to assess water sorption (w sp ) and solubility (w sl ) over 28 days. Statistical analyses were conducted using the Wilcoxon matched-pairs signed-rank test (1-tailed) with 90% power (α=.05)., Results: The mean ±standard deviation flexural strength values were 123.4 ±8.7 MPa for Saremco print Crowntec and 109.9 ±15.8 MPa for Varseo Smile Crown Plus. After aging, these values were 97.5 ±15.2 MPa for Saremco print Crowntec and 94.2 ±11.7 MPa for Varseo Smile Crown Plus. The mean Vickers hardness values were 33.2 ±0.8 N/mm 2 for Saremco print Crowntec and 31.5 ±0.6 N/mm 2 for Varseo Smile Crown Plus. After aging, the mean values were 31.7 ±0.9 N/mm 2 for Saremco print Crowntec and 29.6 ±1.0 N/mm 2 for Varseo Smile Crown Plus. The mean modulus of elasticity was 4.2 ±0.3 GPa for Saremco print Crowntec and 3.82 ±0.2 GPa for Varseo Smile Crown Plus. After 21 days, the mean sorption values were 11.52 ±0.6 mg/mm 3 for Saremco print Crowntec and 12.43 ±0.4 mg/mm 3 for Varseo Smile Crown Plus. After 28 days, the mean solubility values were 1.36 ±0.4 mg/mm 3 for Saremco print Crowntec and 0.98 ±0.3 mg/mm 3 for Varseo Smile Crown Plus. Significant differences were found between the 2 3D-CRs in flexural strength in the dry state (P=.03), in Young modulus after 30 days of water immersion (P=.023), and in Vickers hardness in the dry state (P=.01) and after 30 days of water immersion (P=.018)., Conclusions: Both 3D-CRs provided good in vitro performance and the mechanical properties required for long-term clinical application. Artificial aging decreased the flexural strength of both 3D-CRs., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The clinical failure mode of dental crown ceramics involves radial cracking at the interface, driven by the surface tension generated from the flexure of the ceramic layer on the subsurface. This results in a reduced lifespan for most all-ceramic dental crowns. Therefore, investigating optimal material combinations to reduce stress concentration in dental crown materials has become crucial for future successful clinical applications. The anisotropic complex structures of natural materials, such as nacre, could potentially create suitable strong and damage-resistant materials. Their imitation of natural structural optimisation and mechanical functionality at both the macro- and micro-levels minimises weaknesses in dental crowns. This research aims to optimise cost-effective, freeze-casted bioinspired composites for the manufacture of novel, strong, and tough ceramic-based dental crowns. To this end, multilayer alumina (Al 2 O 3 ) composites with four different polymer phases were tested to evaluate their bending behaviour and determine their flexural strength. A computational model was developed and validated against the experimental results. This model includes Al 2 O 3 layers that undergo gentle compression and distribute stress, while the polymer layers act as stress relievers, undergoing plastic deformation to reduce stress concentration. Based on the experimental data and numerical modelling, it was concluded that these composites exhibit variability in mechanical properties, primarily due to differences in microstructures and their flexural strength. Furthermore, the findings suggest that bioinspired Al 2 O 3 -based composites demonstrate promising deformation and strengthening behaviour, indicating potential for application in the dental field., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Zein-incorporated magnesium oxide nanoparticles (zMgO NPs) can influence the mechanical properties of dental materials. However, the effect of this addition on the mechanical properties of resin composite has yet to be investigated. The objective of this study was to add various concentrations of zMgO NPs to conventional, flowable, and bulk-fill composite and assess the effect on the compressive strength, flexural strength, and microhardness., Methodology: 150 samples each of conventional composite, flowable composite, and bulk-fill composite (n = 450) were enhanced with concentrations of zMgO NPs at 0 %, 0.3 %, 0.5 %, 1 %, and 2 % (n = 30). 10 samples of each group were randomly allotted to the compressive strength, flexural strength, or hardness test. Characterization of the specimens was performed by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. Two-way ANOVA test was used to compare between groups, and one-way ANOVA followed by Tukey's test was done at p = 0.05 to determine significance., Results: Characterization yielded a uniform distribution of nanoparticles in the matrix and the formation of a new hybrid composite that maintained its properties. Composite of all types enhanced with 0.3 % and 0.5 % zMgO NPs demonstrated a statistically significant increase in compressive strength, flexural strength, and hardness when compared to the control (p < 0.05). The bulk-fill composite with zMgO NPs concentrations of all groups demonstrated a statistically significant increase (p < 0.05) in hardness when compared to the control., Conclusion: The modified composites' compressive strength, flexural strength, and hardness improved or remained consistent., Clinical Significance: An improved dental resin composite will enhance the quality of care and patient experience. The augmented strength and hardness of resin composite is desirable in prolonging the durability of the restoration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: To evaluate the fracture resistance (FR) of polyetheretherketone (PEEK) abutments produced by additive and subtractive methods compared to milled zirconia abutments., Methods: Custom abutments were designed on Ti-base abutments and produced from three different materials, namely additively manufactured PEEK (PEEK-AM), subtractively manufactured PEEK (PEEK-SM), and zirconia (N = 60). PEEK-AM abutments were printed using PEEK filaments (VESTAKEEP®i4 3DF-T, Evonik Industries AG) on a M150 Medical 3D Printer (ORION AM) by fused filament fabrication (FFF). All surface treatments were carried out according to the manufacturer's instructions. All abutments were cemented on Ti-bases with hybrid abutment cement and then restored with milled zirconia crowns. Each subgroup was divided into non-aged and aged subgroups (n = 10). The aged groups were subjected to thermomechanical aging (49 N, 5-55 °C, 1.2 million cycles). FR tests were performed by using an universal testing machine. Data were statistically analyzed with one-way and two-way ANOVA and t-test., Results: The survival rate of the specimens after aging was determined as 100%. It was found that both the material and aging had a significant effect on the FR (p<.001). There was a statistical difference among the fracture values of the groups (p<.001). In both the aged and non-aged groups, PEEK-AM showed the statistically lowest FR, while the highest FR was seen in the zirconia group, which was significantly higher than the PEEK-SM (p<.001)., Conclusion: Hybrid abutments were successfully manufactured, and extrusion-based processed PEEK seems to be a good alternative to subtractive processed PEEK. However, since subtractive manufacturing still appears to be superior, further developments in additive manufacturing are needed to further improve the quality of 3D-printed PEEK parts, especially in terms of accuracy and bonding between adjacent layers., Clinical Significance: Additively manufactured PEEK abutments have the potential to be an alternative for implant-supported restorations in the posterior region., Competing Interests: Declaration of competing interest All other authors have no conflicts of interest to declare. The authors do not have any financial interest in the companies whose materials are included in this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)