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Introduction: Self-adhesive resin cements (SARCs) are widely used for fixed prostheses. These cements and their eluted products may affect periodontal tissues. This study aimed to investigate the response of human gingival fibroblasts (HGFs) to eluates from SARCs in vitro, simulating clinical conditions after prosthesis fixation, to gain insights into their potential effects on gingival health., Methods: Two SARCs, RelyX U200 (RX) and Maxcem Elite Chroma (MC), were polymerised according to the manufacturer's protocols using various curing methods (light-cured, light-cured through 1- or 2 mm zirconia, and self-cured). HGFs were exposed to cement eluates at different concentrations. Cell viability, vitality, wound healing, and gene expression were assessed at different time points., Results: Self-cured MC and MC cured through 2-mm zirconia (both undiluted and 1:5 dilution) significantly decreased HGFs' viability. Lower cell viability and vitality were detected in MC compared with RX. Wound healing was delayed in cells treated with MC cured through zirconia compared to those cured with direct light, whereas zirconia had no effect on cells treated with RX. The expression of NRF2, a key regulator of cellular defence against oxidative and toxic insults, showed an increasing trend in cells treated with MC compared to RX. This finding suggests that MC may induce more oxidative stress than RX, leading to a more pronounced inflammatory response in HGFs and aligning with the observed delay in wound healing., Conclusion: The use of MC, especially when cured through zirconia, may negatively impact gingival tissue health, highlighting the importance of carefully selecting cement types and curing methods in clinical practice., Clinical Relevance: This study highlights the potential risks of using MC, especially when cured through zirconia, which may impair gingival tissue health and delay wound healing. Proper choice of cement and curing methods is essential for optimal patient outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate whether the wettability of two zirconia (Zr) implant disk surfaces is affected by glycine and erythritol air polishing using the following wetting solutions as test mediums: saline, bovine serum albumin (BSA), bovine thrombin, and bovine artificial blood., Materials and Methods: The two types of Zr disks used were SDS (Swiss Dental Solutions; n = 6) and Patent (Zircon Medical AG; n = 6). Surface parameters (Sa, Sz, Sdr, Ssk, Sku, and Spd) were measured to determine their initial surface roughness. Air polishing was completed using glycine or erythritol powders using the AIRFLOW PERIO device (EMS Dental). The wettability of the disk surfaces was evaluated by the contact angle analysis applied to the treated and untreated disks using four wetting solutions, including saline, BSA, bovine thrombin, and bovine artificial blood. In total, 720 contact angle measurements were completed with n = 30 per group. Statistical analysis was performed using one-way ANOVA and the post-hoc Tukey HSD test., Results: The results indicate that SDS has a greater wettability than Patent before and after air polishing. The wettability of surfaces treated with glycine was hydrophobic in some cases. Erythritol increased the surface wettability of Zr disks more than glycine. BSA and bovine artificial blood had lower contact angles than saline and bovine thrombin for both types of untreated disks., Conclusions: The initial wettability of Zr disks differs between manufacturers, and air polishing with erythritol powder increases the wettability of Zr implant disks for saline, bovine serum, bovine thrombin, and bovine artificial blood.

Purpose: To evaluate the response of human peri-implant soft tissue (PIST) to different healing abutment materials 24 hours after positioning by assessing the expression of genes related to the early connective tissue wound healing response., Materials and Methods: The following four materials were used to create experimental abutments that were mounted on implants placed in five patients (four different abutments in each patient): group A-grade 4 titanium (Ti), group B-grade 5 Ti, group C-zirconia (Zr), and group D-polyetheretherketone (PEEK). Before implant placement, a gingival biopsy (control, CT) sample was obtained using a 2-mm-diameter punch (T0). After 24 hours, PIST biopsy samples were collected using a specifically designed custom-made cutting device. Real-time polymerase chain reaction (PCR) was performed to analyze the expression of the following genes: COL-I, COL-III, MMP-1, TIMP-1, TGF-β1, FN, ITGA4, ITGA5, ITGB1, RAC-1, COL-IV, αSMA, IL-6, and CXCL-1., Results: Gene expression analysis showed some differences between CT and the experimental groups; however, no significant differences were detected when comparing the experimental groups. COL-I was significantly downregulated in groups A and C compared to CT. Expression of MMP-1 and TIMP-1 increased in all the experimental groups but to a lesser extent in group A. FN, RAC-1, COL-IV, and αSMA were downregulated, especially ingroup A, in which CXCL-1 and IL-6 showed the lowest expression., Conclusions: The results of grade 4 Ti and Zr abutments seem to be promising, because a lower expression of genes related to inflammation, myofibroblast activation, and extracellular matrix remodeling was observed when compared with grade 5 Ti and PEEK, without triggering a profibrotic response in the early phases of PIST repair.

Purpose: To investigate the mid-to-long term clinical outcomes of the implant-supported cross-arch fixed dental prostheses (IFCDPs) with monolithic zirconia-based frameworks and related risk factors of success and survival., Materials and Methods: This retrospective study encompassed individuals exhibiting terminal dentition or edentulism in the maxilla and/or mandible who underwent treatment involving IFCDPs with monolithic zirconia frameworks. Inclusion criteria required a documented follow-up period of at least five years post-definitive prosthesis delivery. Evaluation of outcomes focused on the survival rates of implant and prosthesis, along with the incidence of biological and technical complications. The mixed-effects Cox regression model was employed to analyze the risk factors associated with prosthesis failure and peri-implantitis., Results: A cohort of 47 patients, consisting of 14 women and 33 men with a mean age of 55.2 ± 12.5 years (range: 25-83), was included in this study. The mean follow-up period was 71.6 ±13.2 months (mean ± SD, range: 60-147). A total of 51 cross-arch prostheses supported by 302 implants, distributed between the maxilla (27 prostheses) and mandible (24 prostheses), were assessed. By the end of the follow-up period, 289 (97.64%) of the 302 implants remained functional. Peri-implantitis was observed in 27 implants (24 in mandible), yielding an overall implant-related success rate of 91.06%. Nine frameworks experienced fractures (eight in mandible), resulting in an overall prosthesis-related survival rate of 82.35%. Subsequent analysis revealed the mandible to be a significant risk factor for framework fracture (HR = 11.64, p = 0.024) and peri-implantitis (HR = 10.88, p = 0.003)., Conclusions: The implant-supported cross-arch fixed dental prostheses featuring monolithic zirconia-based frameworks demonstrated favorable clinical outcomes throughout a 5-13-year observation period. Notably, in the design of monolithic zirconia-based framework prostheses, the mandible emerged as a significant risk factor for framework fractures and an independent risk factor for peri-implantitis., (© 2024 by the American College of Prosthodontists.)

Introduction: In every prosthetic treatment, the final purpose of the restoration is to restore function and esthetics for the patient, respecting biology and anatomical parameters. Regarding full coverage restorations, there are some factors to take into consideration: like the finish line (chamfer, shoulder, featheredge, etc.), the management of the provisional restoration and tissue healing, the material for the final restoration, and the impression technique. All these aspects will determine the treatment process and its possible results. In recent years, vertical preparation and more specifically biologically oriented preparation technique has generated great interest since its introduction in prosthodontics, changing the periodontal tissues, and providing long-term stability., Materials and Methods: With this technique, the objective is to change the position of the gingival margin, moving it more apically or coronally, depending on the modifications of the provisional. The relining of the provisional is a fundamental step of this technique: the intrasulcular part of the provisional is modified giving a new emergence profile and providing an augmentation of the tissue in the healing process., Discussion: In vertical preparation, there is no predetermined margin. The dental technician should position the finish line more apically or coronally, depending on the depth of the sulcus and on the esthetic needs. Ceramic restorations should not invade the epithelial attachment, otherwise it may cause biological and mechanical problems, repetition of the impression, and of the crown restoration, which lead to increased clinical and laboratory time usage as well as expenses. One challenge is communicating the shape and contour of the temporary restoration to the dental lab to ensure accurate information for the final restoration., Conclusion: Finally, the objective of this article is to describe a technique for transferring all necessary information of the provisional and obtaining a predictable result for the final restoration by using an intraoral scanner system and the fabrication of two 3D printed prototypes. One for the final volume of the crowns and the other for the finish line position., Clinical Significance: The fabrication of 3D printed prototypes allows for a more predictable final restoration, reducing possible communication errors between clinician and technician when restoring with biologically oriented preparation technique. In any esthetic treatment where the restoration does not have a predetermined margin, it is possible with this additional clinical step to provide a more esthetic outcome., (© 2024 Wiley Periodicals LLC.)

Objectives: This study aimed to compare the outcome of a simplified direct composite resin-bonded fixed dental prostheses without reinforcing fibers (CR-RBFDP) and resin-bonded fixed dental prostheses using zirconia (Zr-RBFDP)., Methods: The clinical records of five private practice dental clinics and one university hospital were analyzed. Failure was defined as a RBFDP that was removed or remade for any reason. Survival analyses were performed using log-rank tests., Results: A total of 45 patients (CR-RBFDP, n = 17; Zr-RBFDP, n = 28) were followed up for 3 years. Among the CR-RBFDP cases, 1 case of framework fracture and 2 cases of discoloration occurred, whereas among the Zr-RBFDP cases, 1 case of debonding occurred. The mean duration of observation was 21.9 months. The 3-year survival rate was 92.3 % for CR-RBFDP and 91.7 % for Zr-RBFDP. Log-rank test showed no significant difference (p = 0.78)., Conclusions: Within the limitations of this short-term retrospective study, the survival rate of CR-RBFDP was not significantly different from that of Zr-RBFDP. Contrary to concerns regarding material strength, CR-RBFDP showed reliable results. This direct composite restoration has the advantages of being less invasive and being completed in a single visit., Clinical Significance: Despite differences in material strength, CR-RBFDPs without fiber reinforcement showed reliable short-term clinical results. This direct composite restoration has the advantage of being less invasive and can be restored in a single visit., 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: This systematic review aimed to determine the effectiveness of various etching surface treatments on zirconia bond strength with the following research question: "Can zirconia etching serve as a viable alternative to airborne particle abrasion (APA) for achieving reliable bonding?"., Data: In vitro studies comparing APA, performed with either conventional or silica-coated aluminum oxide (Al 2 O 3 ) particles, with various etching protocols in terms of bonding performance were included. The risk of bias of the included studies was assessed using the QUIN's tool for in vitro studies. Meta-analyses were performed using RevMan; random-effects models were applied, and heterogeneity was tested using the I 2 index. The significance level was set at p < 0.05., Sources: A comprehensive literature search was conducted across electronic databases, including Clarivate Analytics' Web of Science, Cochrane Library, EMBASE, PubMed, Scopus and ProQuest., Study Selection: Fifty-four relevant articles were included in this systematic review. According to the QUIN's tool, 7 studies were rated as "high risk of bias", 46 studies were rated as "medium risk", and 1 study was rated as "low risk". Nineteen studies were used for meta-analyses. Mostly, APA demonstrated significantly higher bond strength compared to various etching protocols (p < 0.05). However, no statistical difference was found between APA and high concentrations (40-48 %) of hydrofluoric acid (HF) in terms of immediate- and medium-term bond strength to resin composite (p > 0.05). On enamel, an experimental hot etching solution performed significantly better than APA in short-term follow-up (p < 0.05). A novel multi-acid solution exhibited significantly higher immediate shear bond strength to resin cement than APA (p < 0.05). Variable heterogeneity, ranging from low to high, was observed., Conclusions: APA remains the surface treatment with the strongest evidence in the literature and it is usually more efficacious than zirconia etching. However, highly concentrated HF and an experimental hot etching solution have demonstrated similar or significantly higher bond strength values over time compared to APA, depending on the adhesive substrate. A recently introduced multi-acid solution (Zircos-E) needs to be further explored, especially in regards to long-term bond durability., Clinical Significance: This systematic review provides a comprehensive analysis of the existing in vitro evidence on the potential of zirconia etching and the bond durability of resin-based materials after artificial aging. Selecting appropriate surface treatment protocols is crucial for achieving optimal clinical outcomes., 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: This study aimed to investigate the clinical performance of zirconia-based fixed dental prostheses (FDPs) in comparison to metal-ceramic (MC) FDPs., Methods: A comprehensive search on MEDLINE (PubMed), Web of Science (Core Collection), Scopus up to June 2024 was conducted. Studies that compared the success, survival and complication rates between zirconia based FDPs and MC FDPs were eligible for inclusion., Results: Thirty-one articles were identified, of which 22 were included for systematic review and 7 RCTs were included for meta-analysis. 10, 9 and 3 studies were classified to mean follow-up ≤ 5 years, 5 years < mean Follow-up ≤ 10 years, mean Follow-up >10 years, respectively. In the pooled analysis, 180 bilaminar zirconia (ZC) FDPs and 206 MC FDPs were included. ZC FDPs were significantly associated with more failures (RR=3.64, p = 0.009) and more Ceramic Chipping (RR=2.92, p < 0.0001) when compared to MC FDPs. Higher risks of Framework Fracture (RR=4.57, p = 0.18), Loss of Retention (RR=4.79, p = 0.17), Secondary Caries (RR=1.25, p = 0.68), Endodontic complications (RR=1.30, p = 0.74) and Marginal Integrity (RR=1.07, p = 0.88) were also found in ZC FDPs when compared to those of MC FDPs, but with no statistical difference., Conclusion: The current evidence continues to support the preference for traditional MC FDPs over ZC FDPs. Studies indicate that ZC FDPs have higher failure rates and more complications compared to MC FDPs, with ceramic chipping being a significant concern. There is lack of long term (>10 years follow-up) evidence of the clinical performance of ZC FDPs and monolithic zirconia FDPs., Clinical Significance: The study suggests that despite the growing popularity of zirconia, evidence shows MC FDPs may still be considered preferable to ZC FDPs., Competing Interests: Declaration of competing interest This study did not receive any grants from public, commercial, or not-for-profit sectors, (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: This study investigated the effects of build angle and layer thickness on the trueness and precision of zirconia crowns manufactured using digital light processing (DLP) technology., Materials and Methods: Single crowns were fabricated from zirconia using DLP technology. The crowns were manufactured with three different representative build angles (0°, 45°, and 90°) and two different layer thicknesses (30 μm and 50 μm). After printing, the specimens were non-contact-scanned, and their accuracy was assessed using a 3D analysis software. Root mean square (RMS) values were used to determine trueness and precision. Color maps were generated to detect deviations within the specimens. Statistical analyses were conducted using two-way ANOVA., Results: Build angle and layer thickness significantly affected trueness and precision (p < 0.05). At a 30-μm layer thickness, the crowns printed at angles of 0° (32.2 ± 3.2 μm) and 45° (33.9 ± 2.4 μm) demonstrated the best marginal trueness compared to those in other groups (p < 0.05). Notably, those printed at an angle of 90° exhibited the best intaglio surface trueness (37.4 ± 4.0 μm). At a 50-μm layer thickness, the crowns printed at an angle of 90° exhibited the lowest accuracy concerning marginal and intaglio surface aspects (27.7 ± 8.2 μm)., Conclusions: Both the build angle and layer thickness significantly affected the dimensional accuracy of DLP-printed zirconia crowns, with the 30-μm layer thickness offering superior trueness. Optimal results were achieved using build angles of 0° and 45° in conjunction with thinner layers, minimizing marginal defects., Clinical Significance: All zirconia crowns produced at different build angles and layer thicknesses satisfied clinical requirements. Specific combinations of these factors realized the fabrication of single crowns that possessed the highest accuracy., Competing Interests: Declaration of competing interest The authors report no conflict of interest regarding this manuscript., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Debonding of orthodontic brackets on ceramic restorations leave a rough surface which should be efficiently polished. In this study the effect of two diamond polishing systems (DPS), namely Optra Fine® (OF) and Diapol Twist® (DT) on surface roughness (SR) of feldspathic (F), lithium disilicate (LD), and translucent zirconia (TZ) ceramics assessed after bracket debonding., Materials and Methods: Ninety disc-shaped specimens fabricated from F, LD, and TZ ceramics and glazed (Gl). Ten glazed specimens of 3 ceramic types served as control (C) groups (n=30). Other 60 specimens were deglazed, and after specific surface preparation according to ceramic type, upper central incisor brackets were bonded. After debonding, the remaining adhesive composite removed with tungsten carbide bur and specimens randomly assigned into 6 groups. The nine experimental groups defined as: Glazed F specimens (C), Deglazed F specimens polished with DT, Deglazed F specimens polished with OF, Glazed LD specimens (C), Deglazed LD specimens polished with DT, Deglazed LD specimens polished with OF, Glazed TZ specimens (C), Deglazed TZ specimens polished with DT, Deglazed TZ specimens polished with OF. The SR assessed quantitatively by profilometry (Ra and Rz parameter) and qualitatively by scanning electron microscopy (SEM). Quantitative data were statistically analysed using Kolmogorov-Smirnov test, two-way ANOVA and Tukey post-hoc test (α=0.05)., Results: No significant difference found in SR of three glazed ceramic types (P=0.293 for Ra and P=0.473 for Rz). There was no significant difference of Ra between polished and glazed groups (P>0.05). However, difference in Rz was significant (P<0.05), and only TZ specimens could reach to the level of smoothness caused by glazing., Conclusions: Both diamond polishing systems can efficiently reduce the surface roughness, despite of ceramic type. Optra Fine® system showed a superior performance than Diapol Twist® without significant difference., Limitations: In this study only one brand of each ceramic type was investigated. This study was approved by Ethical Review Committee (IR.IAU.KHUISF.REC.1401.156)., (Copyright © 2024. Published by Elsevier Masson SAS.)

Background and Aim: The present investigation explored the potential for recycling residual blocks obtained from the machining processes under hydrothermal conditions. Furthermore, the study examined the recycled samples' various physical and mechanical properties to assess their viability for further use., Materials and Methods: In this in vitro study, Aman Girbach blocks were collected, half of which underwent a hydrothermal process, while the other half did not. The blocks were then subjected to ball milling. Uniaxial and isostatic pressed blocks were prepared, and 10 samples were obtained from each type of recycled block. These samples were compared to a commercial material, and four groups were formed based on the powder type and pressing method used. The quality control analysis of the recycled samples included assessing particle size distribution, identifying crystalline phases, analyzing color differences, examining microstructure, and evaluating mechanical properties. Statistical tests such as normal distribution calculations (k-s test), one-way ANOVA, Brown-Forsythe, Tukey HSD, and Games-Howell tests were used to compare the four groups and perform pairwise comparisons., Results: The flexural strength and density of the control commercial group were significantly higher than the other experimental groups (P = 0.000). Linear shrinkage of recycled isostatic pressed experimental bodies was significantly lower than that of others (P = 0.000). Qualitative evaluation of microstructure and crystalline phase by FESEM and XRD showed no significant difference in grain size and crystalline phase between different groups., Conclusion: The hydrothermal process is a promising way to recycle zirconia ceramic with lower energy consumption. Recycled waste demonstrates potential as a cost-effective and viable option for ceramic prostheses in situations with low to medium stress levels., 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.)

This study examined the impact of interfacial interactions on bilayer yttria-stabilized zirconia (YSZ) used in dental restorations. In-house bilayer structures of 3YSZ and 5YSZ composition underwent hydrothermal degradation to compare the properties of control and low-temperature degradation (LTD) treated groups. Biaxial flexural strength via piston-on-three-balls, staircase fatigue strength over 10 6 cycles at 15 Hz, phase characterization and quantification through XRD and Rietveld refinement, and fractography were conducted. Weibull analysis was employed to determine the Weibull modulus and characteristic strength. Results demonstrated an enhancement in the mechanical performance of 3YSZ composition after LTD treatment, whereas the mechanical properties of 5YSZ remained largely unaffected post-degradation. Fractographic analysis revealed that failure originated at the surface tensile location across all specimen groups. These findings offer insights into the mechanical behavior of bilayer zirconia structures and reinforce the significance of hydrothermal treatment in enhancing their performance, particularly in the case of 3Y compositions., 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: Y-TZP zirconia heads were recalled by the Food and Drug Administration (FDA) in 2001 and zirconia alone was no longer used in orthopedics. Tunnel furnace sintering was suspected of producing defects responsible for early material failure. As Zirconia Toughened Alumina (ZTA) matrices are widely used as bearing material and contain zirconia grains, there remains a need to better understand the in vivo ageing process of zirconia and its clinical implications when the material is produced by batch furnace sintering, the validated sintering process., Questions/objectives: Is there an association between the ageing of batch furnace produced zirconia and THA revision?, Methods: 45 retrieved femoral heads, batch furnace sintered only, were analyzed. Roughness was measured by 3D profilometry, phase transfer by μRaman spectroscopy. Clinical data were compared with material characteristics., Results: Irrespective of the cause of revision, all heads showed a crystallographic phase transition from tetragonal to monoclinic over 19.5%. A correlation was found between the phase change, roughness increase and aseptic loosening, with a threshold set at 24.5% of monoclinic phase., Conclusions: The ageing process of zirconia may lead to aseptic loosening, which, in the absence of contrary evidence, prohibits its use as the sole component of orthopedic materials. ZTA matrices should be clinically monitored, especially in young patients, and better in vitro modelling needs to be performed., Level of Evidence: IV; Case series., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Despite the significant recent advances in manufacturing materials supporting advanced dental therapies, peri-implantitis still represents a severe complication in dental implantology. Herein, a sol-gel process is proposed to easily deposit antibacterial zirconia coatings onto bulk zirconia, material, which is becoming very popular for the manufacturing of abutments. The coatings' physicochemical properties were analyzed through x-ray diffraction and scanning electron microscopy-energy-dispersive x-ray spectroscopy investigations, while their stability and wettability were assessed by microscratch testing and static contact angle measurements. Uniform gallium-doped tetragonal zirconia coatings were obtained, featuring optimal mechanical stability and a hydrophilic behavior. The biological investigations pointed out that gallium-doped zirconia coatings: (i) displayed full cytocompatibility toward human gingival fibroblasts; (ii) exhibited significant antimicrobial activity against the Aggregatibacter actinomycetemcomitans pathogen; (iii) were able to preserve the commensal Streptococcus salivarius. Furthermore, the proteomic analyses revealed that the presence of Ga did not impair the normal oral microbiota. Still, interestingly, it decreased by 17% the presence of Fusobacterium nucleatum, a gram-negative, strictly anaerobic bacteria that is naturally present in the gastrointestinal tract. Therefore, this work can provide a valuable starting point for the development of coatings aimed at easily improving zirconia dental implants' performance., (© 2024 Wiley Periodicals LLC.)

To assess the fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ultratranslucent multilayered zirconia (5Y-YZP) veneers with varying facial thickness. Sixty translucent zirconia veneers were designed and milled using a chairside CAD/CAM system for maxillary central incisors. The butt joint incisal veneer tooth preparations consisted of 1.00 mm incisal reduction, 0.40 mm chamfer margin, and three different facial reductions; 0.50, 0.75, and 1 mm, respectively. The ceramic veneers were cemented to printed resin dies and subjected to thermal cycling. Subsequently, the restorations were loaded with compressive loading force, and fracture occurrences were recorded. Scanning electron microscope (SEM) images of the fractured specimens were captured. The fracture resistance varied among the veneers with different facial thicknesses. Ultratranslucent zirconia veneers with a facial thickness of 1.00 mm exhibited the highest fracture resistance values (742.15 N), followed by those with 0.75 mm facial thickness (673 N). Minimally invasive veneers with 0.50 mm thickness displayed similar fracture resistance as thicker veneers with 0.75 mm. However, veneers with 1.00 mm thickness displayed the highest values. SEM fracture patterns for 0.50 and 0.75 mm display similar and fewer crack lines than 1.00 mm veneers. RESEARCH HIGHLIGHTS: Minimally invasive zirconia veneers exhibit similar fracture resistance to thicker veneers., (© 2024 Wiley Periodicals LLC.)

Objectives: To compare marginal bone levels, biological, and technical outcomes of screw-retained versus cemented all-ceramic implant-supported zirconia-based single crowns after an observation period of 7.5 years., Methods: Forty-four single implants in the esthetic zone in 44 patients (22 females, 22 males) were randomly assigned to two types of restorations: SR (screw-retained); veneered one-piece zirconia abutment and CR (cement-retained); veneered lithium disilicate crown intraorally cemented on a one-piece zirconia abutment. Patients were recalled annually up to 7.5 years and survival rates, biological, and technical parameters assessed., Results: A total of 31 patients attended the 7.5-year follow-up visit (17 SR group, 14 CR group). The survival rate on the restorative level was 77.5% (74.0% CR, 81.0% SR, p = .6399). Median marginal bone loss (MBL) values yielded -0.073 mm (-0.305; 0.238) in the CR and -0.215 mm (-0.500; 0.555) in the SR group (intergroup p = .6194). Mean bleeding on probing (BoP) values were significantly in favor of group SR with 20 ± 17% compared to 40 ± 22% in group CR (p = .011). The overall biological complication rate amounted to 27.5% (42.1% CR, 14.3% SR, p = .0775), whereas the technical complication rate was 32.5% (42.1% CR, 23.8% SR, p = .314). In total, CR restorations showed significantly more complications (84.2% for CR, 38.1% for SR, p = .0041)., Conclusion: One-piece zirconia-based single crowns on two-piece dental implants exhibited a high rate of technical and biological complications at 7.5 years of follow-up. Cemented restorations revealed significant higher rates of bleeding on probing and total complications compared to screw-retained restorations., (© 2024 The Author(s). Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

This review examined the efficacy of surface treatments and adhesive monomers for enhancing zirconia-resin bond strength. A comprehensive literature search in PubMed, Embase, Web of Science, Scopus, and the Cochrane Library yielded relevant in vitro studies. Employing pairwise and Bayesian network meta-analyses, 77 articles meeting inclusion criteria were analyzed. Gas plasma was found to be ineffective, while treatments including air abrasion, silica coating, laser, selective infiltration etching, hot etching showed varied effectiveness. Air abrasion with finer particles (25-53 µm) showed higher immediate bond strength than larger particles (110-150 µm), with no significant difference post-aging. The Rocatec silica coating system outperformed the CoJet system in both immediate and long-term bond strength. Adhesives containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) were superior to other acidic monomers. The application of 2-hydroxyethyl methacrylate and silane did not improve bonding performance. Notably, 91.2 % of bonds weakened after aging, but this effect was less pronounced with air abrasion or silica coating. The findings highlight the effectiveness of air abrasion, silica coating, selective infiltration etching, hot etching, and laser treatment in improving bond strength, with 10-MDP in bonding agents enhancing zirconia bonding efficacy., Competing Interests: 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., (© 2024 The Authors.)

Objectives: To investigate if the fracture load of implant-supported cantilever fixed dental prostheses (ICFDPs) in the anterior region is affected by the implant type and the aging protocol., Materials and Methods: Sixty ICFDPs were prepared using multilayer monolithic zirconia for restoring bone-level (BL) and tissue-level (TL) titanium-zirconium implants. Fracture load was measured at baseline (no aging) or after aging in a chewing simulator loading the implant crown or the cantilever in a 30° angle (n = 10 per group). A two-way ANOVA was applied (α = 0.05) for the effects of implant type and aging protocol., Results: Implant type (p < 0.001) and aging (p < 0.001) had a significant effect on fracture load values. Baseline specimens of both BL (665 ± 62 N) and TL (554 ± 23 N) had significantly higher mean fracture load values than those of aged specimens(BL implant crown 545 ± 46 N, BL cantilever 563 ± 45 N, TL implant crown 455 ± 32 N, TL cantilever 476 ± 24 N) (p < 0.001). The loading position during aging did not affect fracture load values for BL (p = 0.980) nor TL (p = 0.749). BL implants failed by cement fracture and abutment deformation, while for TL the transmucosal part of the implant deformed., Conclusions: The fracture load values of anterior ICFDPs decrease with aging in a chewing simulator. BL implants are preferable over TL implants for anterior ICFDPs as higher fracture load values were achieved, and no implant deformation occurred., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To compare the tensile strength, dislodgement forces, marginal gap and failure types between digitally fabricated zirconia root copings and conventionally manufactured cast gold root copings., Methods: Extracted human teeth (N=30) were prepared for the root copings and randomly divided into 2 groups: (1)zirconia root copings(ZC) and gold root copings(GC). The specimens were tested for tensile bond strength and dislodgement forces in a universal testing machine and the types of the coping failures modes were analyzed. In addition, the marginal gap was measured. Data were analyzed using one-way ANOVA and Pearson correlation test., Results: Mean tensile bond strength in the total horizontal adhesive area for ZC group was 7.5±2.8MPa and for GC group 10.5±4.8 MPa(p⟩0.05). The mean dislodgement forces for the ZC and GC groups were 242±107N and 311±118N, respectively and with no significant differences between the groups (p=0.12). The mean vertical marginal gap in the ZC group amounted to 27±11.05μm, while in the GC group it was 35.33±10.49μm, showing no statistically significant difference between the two groups (p=0.058). Mixed failure modes were more common (93%) in both groups., Conclusions: In terms of all tested parameters, the zirconia root copings were comparable to the gold copings., (Copyright© 2024 Dennis Barber Ltd.)

Background: Primary tooth wear is a common phenomenon that affects chewing ability, dental sensitivity, aesthetics, and occlusion. This study was conducted to compare the antagonistic enamel wear of primary molars opposed to four different crown materials., Methods: Forty lower second primary molars of children aged 4-8 years were allocated into 4 groups: Group 1 (n = 10): received stainless steel crowns; Group 2 (n = 10): received prefabricated commercially available zirconia crowns (NuSmile ® ); Group 3 (n = 10): received locally manufactured zirconia crowns created via the CAD/CAM system; and Group 4 (n = 10): received locally manufactured hybrid ceramic (Vita Enamic ® ) crowns created via the CAD/CAM system. All the crowns were cemented with resin-modified glass ionomer cement. The upper arch was scanned with a 3D intraoral scanner immediately (baseline), 6 months, and 1 year after crown cementation to evaluate the wear of the natural enamel of the antagonistic primary molar. The resultant scans were compared via Exocad software to measure the amount of linear wear of the mesiopalatal cusp of the primary upper second molar., Results: The analysed data revealed statistically significant differences between the studied groups. The highest mean wear was detected in the CAD/CAM zirconia crown group, followed by the NuSmile zirconia crown group and then the CAD/CAM hybrid crown group, and the lowest mean wear was detected for the stainless-steel crown group., Conclusion: Compared with stainless steel crowns, aesthetic crowns cause more wear in the antagonistic primary molar enamel. CAD/CAM zirconia crowns induce the greatest amount of wear, followed by NuSmile zirconia crowns. The CAD/CAM hybrid crown is an aesthetic tooth-coloured crown that causes less wear of the opposing enamel than zirconia crowns do., Trial Registration: The ClinicalTrials.gov Protocol Registration and Results System (PRS) has this RCT registered as (NCT06456879) on 07/06/2024., Competing Interests: Declarations. Ethics approval and consent to participate: Ethical approval for this study was obtained from Mansoura Research Ethics Committee, Faculty of Dentistry, Mansoura University with the code number: M01010222. Written informed consents were signed by the parents prior to examination and treatment of their children. The ClinicalTrials.gov Protocol Registration and Results System (PRS) has this RCT registered as (NCT06456879). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objective: To evaluate the effect of build orientation on the fabrication trueness and fit of additively manufactured 2-piece zirconia abutments when compared with those manufactured subtractively in 3 mol% and 4 mol% yttria-stabilized zirconia (3Y-TZP and 4Y-TZP)., Methods: A titanium-base (Ti-base) abutment was digitized with a scan body and an industrial scanner to design a 2-piece zirconia abutment with a 50 µm cement gap. This design was used to manufacture zirconia abutments additively in different orientations (0-degree, AM-0; 15-degree, AM-15; 30-degree, AM-30; 45-degree, AM-45; 180-degree, AM-180) and subtractively from 3Y-TZP and 4Y-TZP (SM-3 and SM-4) (n=5). An intraoral scanner was used to digitize all abutments, when they were seated on the Ti-base, and only the Ti-base. Abutments' trueness (overall, external, intaglio, and marginal) was analyzed with the root mean square (RMS) method, and their fit was assessed with the triple-scan protocol. Data were analyzed with 1-way analysis of variance and Tamhane's T2 tests (α = 0.05)., Results: SM-3 abutments had the lowest overall and external RMS (P ≤ 0.023). SM-3 and SM-4 abutments mostly had lower intaglio and AM-0 abutments mostly had lower gingival RMS (P ≤ 0.013). Except for AM-0 and SM-3 (P ≥ 0.930), SM-4 abutments had the lowest average gaps (P ≤ 0.041)., Conclusions: SM-3 abutments mostly had higher fabrication trueness, while AM-0 abutments had trueness similar to or higher than the other additively manufactured abutments. AM-0, SM-3, and SM-4 abutments had similar fit with average gaps lower than 50 µm., 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.)

Our study examined how different titanium alloy Ti6Al4V (Ti64) and zirconia (ZrO 2 ) surfaces, ranging from rough to very smooth, affect the expression of elastase (NE), matrix metalloproteinase (MMP)-8, MMP-9, and extracellular traps (NETs) by neutrophils. Discs of Ti64 and ZrO 2 , 10 mm in diameter and 1.5 mm thick, were created using diamond-impregnated polishing burs and paste to produce rough (Ra > 3 µm), smooth (Ra ≥ 1 to 1.5 µm), and very smooth (Ra < 0.1 µm) surfaces. Neutrophils from Wistar rats were cultured on these surfaces, and the culture supernatants were then examined for NE, MMP-8, and MMP-9 using ELISA. At the same time, NET formation was demonstrated immunohistochemically by staining neutrophils with CD16b and DNA with DAPI. Overall, the expressions of NE and MMP-8 were significantly higher from neutrophil culture on Ti64 and ZrO 2 rough surfaces compared to the very smooth surface (R > S > VS) after 2 h and 4 h of culture. The expression of MMP-9 also increased with culture time; however, no significant surface effects on expression were observed. Similarly, rough Ti64 and ZrO 2 surfaces (R & S) also showed significantly larger NET formation compared to the very smooth surface (VS) after 4 h and 8 h cultures. Our findings suggest that increasing surface roughness on Ti64 and ZrO 2 triggers higher NE, MMP-8, and NET formation secretion.

Purpose: The purpose of this study was to investigate and compare in vitro the influence of preformed metal crowns (PMC) versus zirconia crowns (ZC) on the extent of artifact formation and the diagnostic quality of magnetic resonance imaging (MRI)., Methods: Standard crown tooth preparations were performed on Typodont models. PMC and ZC were cemented on all primary molar teeth (n = 8) of the respective models. MRI scans were taken for the Typodont alone (control), PMC, and ZC, using a 3 T MRI machine and common MRI sequences. The diameter of image distortion was measured around the dental materials. Data was analyzed using a mixed model analysis., Results: The average artifact size for PMC was 54.9 mm (range 19.6-110.7 mm) and 12.8 mm (range 5.5-20.7 mm) for ZC. The artifact size was associated with the MRI pulse sequence and dental material, with PMC showing larger artifact diameters than ZC for all MRI sequences (p < 0.001). The control had sensitive sequences for AxT2* and DWI sequences with MRI artifacts of 11.4 mm and 10.7 mm, respectively., Conclusions: It is important that dentists are aware of the potential of dental materials to cause unfavourable MRI artifacts. When areas of the brain requiring MRI preclude the use of PMC, ZC may be considered as an alternative to extractions. Further clinical studies are required to evaluate the impact of dental materials on the image quality of MR scans in vivo., Competing Interests: Declarations Conflict of interest The authors have no conflicts of interests to declare. Consent to publish The authors affirm that informed consent was obtained from the parents of the participants for publication of the images in Fig. 2., (© 2024. The Author(s), under exclusive licence to European Academy of Paediatric Dentistry.)

Objectives: To assess the influence of different primer compositions-silane (S), 10-methacryloyloxydecyl dihydrogen phosphate (MDP), and the combination of silane and MDP (S + MDP)-on the bonding performance of MDP-free and MDP-containing resin cements to highly translucent zirconia., Materials and Methods: Tribochemical silica-coated zirconia plates were pretreated with one of three experimental primers, S, MDP, or S + MDP, with untreated specimens serving as controls. Subsequently, these plates were bonded to stainless-steel rods using either two MDP-free or two MDP-containing resin cements. Tensile bond strength was measured after 24 h (TC0) and following thermal cycling (4-60 °C for 10,000 cycles; TC10,000). Data were analyzed using a three-way analysis of variance (ANOVA), followed by one-way ANOVA and Tukey-Kramer post hoc tests (α = 0.05). X-ray photoelectron spectroscopy (XPS) assessed the elemental mass concentrations on the zirconia surfaces., Results: For MDP-free resin cements, MDP-treated specimens exhibited significantly greater bond strengths than controls, regardless of the aging conditions. However, a significant reduction in bond strength was observed between TC0 and TC10,000 in most of the MDP-free resin cement groups, except for one S + MDP group. Conversely, for MDP-containing resin cements, the S + MDP group exhibited no statistically significant differences between aging conditions. Notably, XPS analysis detected silicon, zirconium, and aluminum on the zirconia surfaces., Conclusions: No significant difference in tensile bond strength was observed between aging conditions for MDP-containing resin cements bonded to tribochemical silica-coated zirconia primed with S + MDP., Clinical Relevance: The combination of MDP-containing primers and resin cements demonstrated superior bonding performance to tribochemical silica-coated zirconia., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Dental implants made of zirconia (ZrO 2 ) are a potential alternative for titanium implants in dentistry because of their good biocompatibility, mechanical properties and excellent aesthetic results. However, solid long-term scientific data to prove clinical success of ZrO 2 implants are scarce., Aim: The aim of this study was to describe and to examine the clinical performance of custom-made two-piece ZrO 2 implants, to identify possible influencing factors: a) manipulation of the implant after placement and b) the occlusal scheme on the survival rate, and to evaluate the performance of the implant-supported crown. This follow-up study collected and examined the 5-year data to answer the main question: What are the survival and the success rates of custom-made ZrO 2 implants in the maxillary premolar region after 5 years?, Material and Methods: Of the 31 included patients in this prospective 5-year follow-up single-arm clinical trial, 30 received a custom-made ZrO 2 implant to replace a missing single maxillary premolar, which was subsequently restored with a lithium disilicate crown. Parameters regarding clinical performance, marginal bone-level (MBL) changes, and patient-related outcome measures (PROMs) were assessed preoperatively, at the baseline, as well as 1 and 5 years after crown placement. Chances of survival and success of the implant were calculated and displayed using Kaplan-Meier statistics. Kaplan-Meier survival analysis was also performed with stratification based on the variables "manipulation of the implant prior to impression taking" and "occlusal scheme" and compared using log-rank tests. Bone-level moderation in time was compared using a paired samples t-test. Patient's expectations and satisfaction after 5 years were compared as a measure of fulfilled expectations, using a Wilcoxon signed-rank test. Performance of the implant-supported crowns was evaluated using validated criteria., Results: Survival and success probabilities after 5 years were, respectively, 75.8% (95% CI [60.0%; 91.0%]) and 71.0% (95% CI [54.0%; 88.0%]) for the custom-made ZV3 implants. No significant differences in survival rate were found after stratification on "manipulation of the implant" and on "occlusal scheme." Mean bone-level alteration between baseline and the first follow-up was +0.06 mm (95% CI [-0.23 mm; 0.12 mm]; SD = 0.42 mm) and between baseline and the second follow-up was +0.04 mm (95% CI [-0.35 mm; 0.26 mm]; SD = 0.54 mm). Patients' satisfaction for patients with implants still in function after 5 years was 91.7% (IQR = [90.5%-97.3%]), indicating satisfaction with the treatment. Pooled satisfaction in patients with successful implants after 5 years was significantly higher than patients' expressed expectations before treatment. None of the crowns failed, and no interventions were required., Conclusion and Clinical Implications: Survival rate of these particular ZV3 implants in our study was lower than expected and clinically not acceptable. Hence, ZV3 implant placement as applied in this study cannot be recommended for clinical practice. Further research on the different appearances of mechanical failure in ZrO 2 implants would be highly recommended before a larger prospective randomized clinical trial is conducted to evaluate treatment with custom-made ZrO 2 dental implants., (© 2024 The Author(s). Clinical Implant Dentistry and Related Research published by Wiley Periodicals LLC.)

Objective: The purpose of this study was to assess the accuracy of full coverage crowns produced by two manufacturing methods: additive 3D printing and subtractive milling utilizing three different predefined cement spaces., Materials and Methods: Six groups were allocated based on the manufacturing method and the predefined cement space: printed wax with a 20 µm space (PW1); printed wax with a 50 µm space (PW2); printed wax with a 100 µm space (PW3); milled wax with a 20 µm cement space (MW1); milled wax with a 50 µm cement space (MW2); milled wax with a 100 µm cement space (MW3); milled zirconia coping with a 20 µm cement space (MZ1); milled zirconia coping with a 50 µm cement space (MZ2); milled zirconia with a 100 µm cement space (MZ3). All fabricated specimens were scanned using an Identica Blue 3D scanner and saved as standard tessellation language (STL) files. A triple scan method was performed using 3-matic software to assess accuracy. The discrepancy values were recorded in micrometers, and the analysis was conducted using one-way ANOVA., Results: The wax printing method, with a cement gap design of 100 μm, demonstrated a significant improvement in the accuracy compared to the other methods (P<.01). In contrast, the zirconia milling method exhibited significantly lower accuracy relative to the other techniques (P<0.01). Moreover, different cement spaces resulted in various accuracy levels but the only statistically significant difference was observed for the 100 µm cement space in the printed wax group., Conclusion: The additive 3D printing method exhibited greater accuracy than the subtractive milling approach. Furthermore, altering the cement gap was found to impact the accuracy of both techniques, albeit without statistical significance., Clinical Significance: The accuracy of each CAM technique was investigated in this study, highlighting the promising accuracy of 3D-printed patterns for the lost-wax technique over direct crown milling. However, all methods produced reliable and accurate crown restorations.

Although there are difficulties with using intraoral scans for implant-supported complete-arch fixed dental prostheses (ISCFDPs), several commercially available systems have become helpful in simplifying the treatment process in the prosthetic phase. These systems help patients move from interim ISCFDPs to receiving definitive prostheses in just three clinical visits. This clinical report summarizes the indications, benefits, and limitations of the four systems. The information provided in this report about the digital prosthetic workflow of ISCFDPs aims to help clinicians make well-informed choices and improve treatment results. With digital technologies advancing, refining these tools and protocols, and validating research is crucial for continued evolution in the field., (© 2024 The Author(s). Journal of Prosthodontics published by Wiley Periodicals LLC on behalf of American College of Prosthodontists.)

Objectives: To proof the feasibility of direct colour printing on 3Y-TZP using 222 nm UV-C through investigating the degree and durability of the colour changes, and testifying whether surface, mechanical and biological properties are influenced by the treatment., Methods: 222 nm UV-C light (Irradiance: 1.870 mW/cm 2 ) was used to treat 3Y-TZP for durations from 15 min to 24 h. ΔE*, TP, crystalline structure, surface morphology, S a , BFS and biological activities were investigated before and after irradiation. SPSS 28.0 was used for statistical analysis (α = 0.05)., Results: 222 nm UV-C irradiation was capable to shade white 3Y-TZP into tooth colours. With the increase of ΔE*, TP decreased, such that the longer the irradiation time, the higher the ΔE* (logarithmic relationship) and lower the TP. Despite the induced optical changes being prone to fade, the process can be predicted by inversely proportional relationships between ΔE*, TP and the testing points. The treated surface exhibited enhanced hydrophilicity, while the recovery phenomenon was observed. Other properties were not altered by the treatment., Significance: This is the seminal study demonstrating the feasibility of direct colour printing on 3Y-TZP using 222 nm UV-C. The new relationship between the colour centre and E g of 3Y-TZP was established, whereas the induced optical changes were stabilised after a certain period and were highly predictable by controlling the irradiation periods. The irradiation was only correlated to the electron excitation and oxygen vacancies, and would not lead to any changes of other properties. A simple, safe and promising approach to achieve satisfactory colours on 3Y-TZP in clinical practice can be developed., Competing Interests: Declaration of Competing Interest There are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The purpose of this study was to evaluate the influence of simplified ceramic surface treatments on the microshear bond strength (μSBS) of 2 resin cements to a zirconia-reinforced lithium silicate (ZLS) material. Blocks of ZLS were sectioned to obtain a total of 90 specimens (1.5 mm thick), which were assigned to 9 different surface treatment protocols (n = 10). Either hydrofluoric acid (HF) surface conditioner or ammonium polyfluoride self-etching ceramic primer (Monobond Etch & Prime [MEP]) was used for surface treatment and then combined with different bonding strategies (Monobond N silane-based universal primer, Prosil silane coupling agent, Ambar Universal APS self-etching adhesive, and/or Signum Zirconia Bond methyl methacrylate-based bonding system [SZB]) and luting agents (Allcem or Multilink Automix dual-curing resin cement). Composite resin cylinders were bonded to ZLS with each of the cementation protocols, and the specimens were subjected to 6000 thermal cycles from 5°C to 55°C prior to the μSBS evaluation. The failure mode was analyzed with the aid of a stereoscopic loupe. Statistical analyses were performed with 1-way analysis of variance and Tukey HSD test (α = 0.05). The HF and MEP protocols resulted in significantly higher μSBS values (P < 0.001), while conditioning with SZB resulted in the lowest μSBS. Multilink Automix groups presented higher μSBS values than Allcem groups (P < 0.01). There was no statistically significant difference in the μSBS values of the MEP + Allcem groups based on whether or not an adhesive layer was applied. The failure mode was predominantly adhesive for all specimens. The results indicate that the ammonium polyfluoride-based material MEP may be used as a substitute for surface treatment with HF and silane, but the use of a zirconia primer alone is not advised for bonding to a ZLS ceramic material., Competing Interests: No conflicts of interest reported.

Objectives: This study was to investigate the effects of optimized microstructured surfaces on bond strength and bond durability of the latest nanoparticle jetting (NPJ)-printed zirconia., Methods: Zirconia microstructured surfaces with different geometries and void volume were analyzed through three-dimensional finite element analysis for surface micromorphology optimization. Zirconia disks and cylinders were additively manufactured by an NPJ 3D printer (N = 128). They were randomly divided into four groups based on surface micromorphology optimization and airborne-particle abrasion (APA) treatment before they were bonded using 10-methacryloloxydecyl dihydrogen phosphate (MDP) containing resin cement (Clearfil SA luting cement). The shear bond strengths (SBSs) were tested before and after 10,000 thermocycles and were analyzed by one-way ANOVA analysis. Failure modes were determined by optical microscopy. Zirconia surfaces were analyzed with X-ray diffraction, scanning electron microscopy, and three-dimensional interference microscopy., Results: The optimized microstructured surface was characterized by circular microstructures with 60 % void volume, about 20 µm of depths, about 10 µm of undercuts, and consistent beam widths. The optimized microstructured surface combined with APA treatment and MDP-containing resin cement possessed the highest SBSs both before and after thermocycling aging (P＜0.05). The greater reductions of zirconia bond strengths occurred when the zirconia were not treated with APA (P＜0.05)., Significance: The optimized microstructured zirconia surface with circular microstructures and 60 % void volume fabricated by the latest NPJ printing technology could greatly enhance the zirconia bond strength and durability in combination with APA treatment and application of MDP-containing resin cement, which might be promising for adhesively bonded indirect restorations of NPJ-printed zirconia., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Aim: To evaluate the micro-shear bond strength (µ-SBS) of resin-modified glass ionomer cement and to assess the chemical and topographical changes in the zirconia fitting surface induced by acidulated phosphate fluoride (APF) gel using scanning electron microscope (SEM) analysis and Fourier transform infrared (FTIR) spectroscopy., Materials and Methods: Thirty-two samples were prepared from two zirconia materials, UPCERA HT White and BruxZir ® Solid Zirconia, milled by a computer-aided design/computer-aided manufacturing system. From each zirconia sample, six plates were prepared for FTIR and SEM testing. Following sintering, the samples were divided into control and test groups for each material. The APF gel (1.23%) was applied to the intaglio surface of each test group. To measure the µ-SBS between the zirconia materials and luting cement, 20 rectangular samples of zirconia material were prepared. Ten samples were obtained from Upcera and ten from Bruxzir, with five assigned to the control and five to APF groups., Statistical Analysis: For the µ-SBS test, independent samples t test was conducted to determine the level of significance between the tested groups., Results: FTIR spectroscopy revealed new bands for Upcera and Bruxzir zirconia owing to ion exchange between the formed sodium phosphate and the zirconia surface and the formation of zirconium phosphate by an ester reaction. SEM assessment identified lines, scratches, or surface dissociation that appeared on the intaglio-zirconia surface after conditioning. The µ-SBS test, as indicated by the independent samples t test, showed a significant increase in bond strength of 1.266 and 1.566 MPa for Upcera and Bruxzir zirconia, respectively., Conclusion: This study offers new practical, cost-effective, and accurate tests to enhance the µ-SBS of luting cement to yttria-stabilized tetragonal zirconia polycrystal ceramics., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of International Society of Preventive and Community Dentistry.)

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).)

Objective: The study aims to evaluate the stress distribution on tooth and restoration of zirconia endocrowns with pulp chamber or intracanal extension and zirconia post performed maxillary first molar using finite element analysis., Method and Materials: Three three-dimensional endodontically treated maxillary molars were modeled. Cortical bone and cementum were modeled 2 mm and 200 μm in thickness. Periodontal ligament at 250 μm thickness was constructed. Zirconia endocrown with pulp chamber extension of 2 mm (Model E&#43;PCE), zirconia endocrown with intracanal extension of 4 mm (Model E&#43;ICE), and zirconia post of 4 mm and crown (ZP) were modeled using software. All restoration models were placed on the maxillary molars. Models were subjected to 400 N loading from the three occlusal contact points. Von Mises stress was recorded., Results: Expectingly, points where the stress was applied showed high stress compared to other regions of the models. The stress did not occur at the trifurcation in any of the models. For the stresses occurring in the restoration material, there were 14.67 MPa, 57.79 MPa, and 155.56 MPa, in Models E&#43;PCE, E&#43;ICE, and ZP, respectively. At the remaining dentin, these values were 47.04 MPa, 32.85 MPa, and 33.42 MPa in Models E&#43;PCE, E&#43;ICE, and ZP, respectively., Conclusions: Within the limitation of the study, zirconia endocrowns with intracanal extension exhibit more favorable stress distribution in both restoration material and dentin compared to zirconia posts and pulpal extension endocrowns. These findings suggest that endocrown with intracanal extension may be a better restorative option for reducing stress.

Objective: We assessed the changes in optical properties and biocompatibility of transition zones in multilayered translucent monolithic zirconia exposed to prolonged hydrothermal aging and compared the results to those with different yttrium oxide contents., Materials and Methods: Four types of zirconia blocks from IPS e.max ZirCAD were used: 3Y-TZP e.max ZirCAD LT (ZL), 4Y-TZP e.max ZirCAD MT (ZM), 5Y-TZP e.max ZirCAD MT Multi (ZT), and 3Y/5Y-TZP e.max ZirCAD Prime (ZP). A total of 120 specimens (15.0 mm diameter and 1.5 mm height) were fabricated and divided into three groups ( n = 10). The aging process for the specimens was conducted in an autoclave set to 134 °C and 0.2 MPa, with durations of 0 h (control), 5 h (first aged), and 10 h (second aged). The optical properties and biocompatibility were analyzed, followed by a statistical analysis of the data (α = 0.05)., Results: Before and after aging, ZL and ZP exhibited the lowest color changes. ZT exhibited the highest average transmittance and translucency parameter values, while ZL had the lowest. The water contact angle test showed the highest value in ZM and lowest in ZL across all the aging stages. ZL, ZM, and ZP showed a considerable decrease in the water contact angle; however, ZT did not. A cell counting kit-8 assay showed ZL had the highest value, while ZM had the lowest. A filamentous actin test exhibited the highest value in ZL and lowest in ZM. In the vinculin analysis, ZL and ZT exhibited the lowest values, whereas ZM and ZP had the highest., Conclusion: 3Y/5Y-TZP exhibited a balanced performance across critical parameters, such as color stability, translucency, and biocompatibility, aligning with 3Y-TZP. While 5Y-TZP demonstrated superior translucency, it confirmed the lowest color stability, whereas 3Y-TZP achieved the highest biocompatibility. These properties provide clinicians with a reliable material option that ensures superior esthetic outcomes and long-term prognosis, ultimately contributing to improved patient satisfaction and clinical longevity.

Objective: To investigate whether nonthermal atmospheric plasma (NTAP) can promote bonding between commonly used adhesive monomers and zirconia., Materials and Methods: The zirconia surface and monomers (HEMA, BisGMA, TEGDMA, and MDP) were treated with different NTAP approaches (10 w, 30 s), and the surface characteristics and chemical structures between the zirconia surface and monomers were verified by the contact angle, scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR/FT-IR) spectroscopy, and x-ray photoelectron spectroscopy (XPS). Scotchbond Universal adhesive with two different resin cements, RelyX Ultimate and RelyX Unicem 2, was applied, followed by NTAP-aided clinical procedures, and then microtensile bond strength test (μTBS) and failure mode evaluation were tested for preliminary mechanical properties assessment. One-way ANOVA was employed for the statistical analysis., Results: The contact angle analysis, SEM, and ATR-FTIR confirmed that NTAP can promote the polymerization of BisGMA, TEGDMA, and MDP on the zirconia surface, while XPS confirmed that NTAP can induce a chemical reaction between MDP and zirconia., Conclusions: Nonthermal atmospheric plasma can increase the affinity between selected monomers and zirconia and promote the chemical bonding strength between phosphate monomers and zirconia; besides, it can enhance the bonding strength of two different adhesive systems., Clinical Significance: The mechanism of how NTAP improved common adhesive monomers interacting with zirconia surfaces was revealed in this study. NTAP, as a relatively high energy-boosting method, could not only improve the surface affinity of zirconia and chemical bonding in-between monomers and zirconia but also enhance the polymerization of different monomers onto zirconia, resulting in improved bonding properties. Thus, further exploration of versatile bonding materials and/or onto different dental substrates could take this into account., (© 2024 Wiley Periodicals LLC.)

Optical characteristics and microstructure of multilayered zirconia with different yttria contents in each layer can be influenced differently with a layer after speed sintering. The layer-wise translucency and opalescence of dental zirconia (E.max, E.max ZirCAD prime; Cercon, Cercon ht ML) after conventional (control) and speed sintering were analyzed using a spectrophotometer (n = 5). Specimens were subjected to microstructural analyses (n = 2) using field-emission scanning electron microscopy (FE-SEM) and phase analyses (n = 1) using high-resolution X-ray diffraction (HRXRD) and Rietveld refinement. The translucency parameter (TP) and opalescence parameter (OP) were analyzed using a 3-way ANOVA, followed by Scheffé's post hoc test (α = 0.05). The average grain size was analyzed using the Welch's t -test and Kruskal-Wallis test, followed by the Bonferroni-Dunn post hoc test (α = 0.05). Changes to the TP and OP after speed sintering were only observed in the dentin layers. Although the TP of E.max increased ( p < 0.05), the difference was below the 50:50% perceptibility threshold (ΔE 00 = 0.8). The OP of E.max decreased slightly, whereas that of Cercon increased slightly ( p < 0.05). The microstructure and phase fraction of both zirconia barely changed. Therefore, speed sintering is considered to have a negligible clinical impact on the optical characteristics and microstructure.

Introduction: The marginal fit of dental restorations is essential for longevity and effectiveness of fixed prostheses, particularly single-unit crowns. Direct digital scanning offers significant advantages over indirect methods, providing a non-invasive, accurate, and reproducible means to evaluate marginal fit. This study aimed to assess the marginal fit of single-unit copings fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia, direct metal laser sintering (DMLS), and porcelain-fused-to-metal (PFM) utilizing direct three-dimensional (3D) scanning., Materials and Methods: The current in vitro investigation involved 60 right mandibular second premolar typodont teeth (Dentmark, Ambala, Haryana, India) designated for single-unit fixed dental prostheses. The specimens were categorized into three groups of 20 specimens each. Direct scanning for all groups was performed using the Helios 500 intraoral scanner (Orikam Healthcare India Pvt. Ltd., Haryana, India). Upon fabrication, all copings were directly scanned using a 3D scanner (Shining 3D EX Pro, California, USA). Marginal discrepancies were assessed using the Exocad software (CAD software, Darmstadt, Germany)., Results: Mean marginal discrepancies of zirconia, DMLS, and PFM copings were evaluated and compared. Zirconia copings had the lowest mean discrepancy of 0.0172 mm whereas DMLS copings had a mean discrepancy of 0.0256 mm. The PFM copings had the highest mean discrepancy of 0.0375 mm. A one-way analysis of variance (ANOVA) indicated a significant difference in the marginal fit (p < 0.05). Post-hoc Tukey test comparisons revealed significant differences between the three groups (p < 0.05)., Conclusion: In conclusion, CAD/CAM-fabricated zirconia crowns exhibit superior marginal fit compared to DMLS and PFM copings, owing to precise digital design, milling, and material stability. DMLS copings, although less precise, still outperform PFM crowns, which display significant marginal gaps owing to the limitations of the lost-wax method., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Kale et al.)

The principles of tissue preservation, minimally invasiveness and approaching different clinical situations biologically rather than surgically govern today's dentistry. Thus, different clinical scenarios require procedures that offer the dentist and the patient the possibility to choose the more invasive treatment options later in life. Subsequently, the case reported refers to a minimally invasive technique that treats single tooth edentulism using single partial retainer FDPs fabricated from monolithic zirconia. This approach is conservative, biocompatible, aesthetic, strong, rapidly obtained through CAD/CAM techniques and cost-effective., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Clinical Case Reports published by John Wiley & Sons Ltd.)

Purpose: This study investigated the fracture resistance of 0.5-mm-thick restorations for minimally invasive therapy. Anterior partial-coverage crowns composed of three-dimensional (3D)-printed 3-mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP; Lithacon 3Y210, Lithoz) and 3D-printed composite (Varseo Smile Crown plus, Bego) were compared with a control group made from milled 3Y-TZP (Cercon ht, DentsplySirona)., Methods: Three groups each with 27 restorations were produced. For milled 3Y-TZP partial-coverage crowns, drill compensation was needed so the milling bur could access the inner surface at the incisal edge. Restoration fit was verified by cross-sectioning 12 specimens in each group. The remaining 15 restorations were sandblasted (Al2O3, 0.1 MPa) and adhesively cemented (Panavia SA, Kuraray) onto CoCr teeth. Static load-to-failure tests were performed. The load was induced on the incisal edge. The forces needed to fracture the specimens were analyzed using the Welch analysis of variance and post hoc Dunnet-T3 tests. The Weibull parameters were also calculated., Results: Drill compensation increased cement thickness at the loading area by 200 µm in milled 3Y-TZP restorations compared with the 3D-printed partial-coverage crowns. Fracture resistance was the highest in 3D-printed 3Y-TZP restorations (1570±661N) followed by milled 3Y-TZP (886±164N) and 3D-printed composite partial-coverage crowns (570±233 N). Milled 3Y-TZP was associated with a substantially higher Weibull modulus (m=6) than the 3D-printed materials (m=2), suggesting greater reliability., Conclusions: Fracture resistance increased with tighter fit, demonstrating the benefit of the geometric freedom associated with 3D-printing. Future research should focus on making 3D-printed 3Y-TZP more reliable to increase its safety in clinical use.

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.

Objectives: Coculture models are limited by bacteria rapidly outcompeting host mammalian cells for nutrients in vitro , resulting in mammalian cell death. The goal of this study was to develop a coculture model enabling survival of mammalian cells and oral bacterial species to assess their competition for growth on dental implant materials. Methods: Two early colonizing oral bacterial species, Streptococcus mutans or Actinomyces naeslundii , were grown in coculture with primary human macrophages or human gingival fibroblasts for up to 7 days on tissue-culture treated polystyrene or polished titanium and zirconia disks. Chloramphenicol was supplemented in cell culture medium at bacteriostatic concentrations to maintain stable bacterial inoculum size. Planktonic and adherent bacterial growth was assessed via spot plating while mammalian cell growth and attachment were evaluated using colorimetric metabolic assay and confocal fluorescence microscopy, respectively. Results: Macrophages and fibroblasts proliferated in the presence of S. mutans and maintained viability above 70% during coculture for up to 7 days on tissue-culture treated polystyrene and polished titanium and zirconia. In contrast, both mammalian cell types exhibited decreasing proliferation and surface coverage on titanium and zirconia over time in coculture with A. naeslundii versus control. S. mutans and A. naeslundii were maintained within an order of magnitude of seeding inoculum sizes throughout coculture. Significance: Cell culture medium supplemented with antibiotics at bacteriostatic concentrations can suppress bacterial overgrowth and facilitate mammalian cell viability in coculture model systems. Within the study's limitations, oral bacteria and mammalian cell growth in coculture are comparable on polished titanium and zirconia surfaces.

Objectives: To evaluate the fracture resistance of veneered incisor crowns made from highly translucent zirconia frameworks. Materials and Methods: Ninety-six all-ceramic single crowns were based on either a coping with minimum wall thickness or a cutback framework fabricated from highly translucent zirconia (5Y-PSZ). Each one-third of the specimens was finalized with different veneering ceramics using standardizations and glaze firing. Crowns were luted to cobalt-chromium dies with MDP-containing composite cement. Half of the entire sample underwent artificial aging (chewing simulation and thermocycling) before fracture load tests were conducted using a 6 mm steel sphere applied in a 90° angle to the oral aspect of the crowns with 1.3 mm distance to the incisal edge. Besides descriptive presentation of recorded forces at first damage (F 1d ) and fracture (F u ), Kruskal Wallis and Mann-Whitney U tests were used to analyze data at α  = 0.05. Results: Directly after manufacturing, incisor crowns of all test groups showed sufficient mean fracture resistances. After artificial aging, crack formation was observed in a high percentage for fully veneered crowns of all test groups, but only for one veneering ceramics with cutback crowns. Mean test forces of unaged crowns were F 1d,mean  ≥ 422 N | F u,mean  ≥ 749 N (fully veneered) and F 1d,mean  ≥ 644 N | F u,mean  ≥ 706 N (cutback) dropped significantly to F 1d,mean  ≥ 131 N | F u,mean  ≥ 223 N (fully veneered) and F 1d,mean  ≥ 324 N | F u,mean  ≥ 524 N (cutback) . Conclusions: Within the limitations of this laboratory study, 5Y-PSZ based anterior crowns can be a viable treatment option. Framework design, choice of the veneering ceramics and artificial aging show relevant effects on the fracture resistances. Concerted veneering ceramics should be used and partially veneering of the zirconia frameworks should be favored over full veneers., Competing Interests: All authors declare that they have no conflicts of interest regarding this research. None of the authors is paid consultant of Dentsply Sirona or received any personal money. The company took no influence on the study outcome, outcome interpretation or the manuscript., (Copyright © 2024 Andreas Zenthöfer et al.)

ZnO/ZrO 2 catalysts have shown better activity in the CO 2 hydrogenation to methanol compared with single component counterparts, but the interaction between ZnO and ZrO 2 is still poorly understood. In particular, the effect of the ZrO 2 support phase (tetragonal vs. monoclinic) was not systematically explored. Here, we have synthesized ZnO/ZrO 2 catalysts supported on tetragonal ZrO 2 (ZnO/ZrO 2 -t) and monoclinic ZrO 2 (ZnO/ZrO 2 -m), which resulted in the formation of different ZnO x species, consisting of sub-nanometer ZnO moieties and large-sized ZnO particles, respectively. ZnO/ZrO 2 -t exhibited a higher methanol selectivity (81 vs. 39 %) and methanol yield (1.25 vs. 0.67 mmol g -1  h -1 ) compared with ZnO/ZrO 2 -m. The difference in performance was attributed to the redox state and degree of dispersion of Zn, based on spectroscopy and microscopy results. ZnO/ZrO 2 -t had a high density of ZnO x -ZrO y sites, which favored the formation of active HCOO* species and enhanced the yield and selectivity of methanol along the formate pathway. Such ZnO clusters were further dispersed on ZrO 2 -t during catalysis, while larger ZnO particles on ZnO/ZrO 2 -m remained stable throughout the reaction. This study shows that the phase of ZrO 2 supports can be used to control the dispersion of ZnO and the catalyst surface chemistry, and lead to enhanced catalytic performance., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

This study aimed to evaluate the optical properties of liner-treated CAD/CAM Multi-colored lithium disilicate (Amber Mill Direct; AMD) and multi-layered zirconia (Omega multi; OM) implant-supported crowns, as well as their effect on the fracture strength of Ti or Zr abutments to which they were applied. After sintering AMD and OM ceramic blocks, they were classified into three groups: untreated, liner-treated, and liner-treated with added color. Optical properties were evaluated by analyzing color differences using background materials to assess translucency and the masking ability of liner-treated ceramics. Subsequently, the fracture strength of implant-supported crowns applied to Ti or Zr abutments was measured, and statistical analysis was conducted using Weibull statistics. Untreated AMD exhibited the highest translucency. Liner treatment reduced translucency in both ceramics, while color-added liner treatment increased translucency. Liner-treated AMD showed greater color difference compared to OM, whereas color-added liner treatment reduced the color difference. Fracture strength was highest in Ti abutment-OM crowns (548.03 N) and lowest in Zr abutment-AMD crowns (283.58 N). Additionally, the Weibull coefficient was over twice as high in Ti abutment-AMD crowns (m = 17.500). Color liners can adjust the high translucency of lithium disilicate ceramics to block discoloration, providing natural tooth-like color and enabling the creation of esthetic restorations. Furthermore, lithium disilicate ceramic crowns applied to Ti abutments exhibited high Weibull coefficients and fracture strengths., (© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

The rise of computer-aided design and computer-aided manufacturing (CAD/CAM) and 3D printing technologies in orthodontics has revolutionized the development of customized labial and lingual bracket systems with a variety of materials, which offer potential advantages over traditional orthodontic brackets. To highlight the current state of knowledge regarding the mechanical and clinical properties of CAD/CAM and 3D-printed custom bracket systems, we conducted a comprehensive search across the PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases to identify relevant articles published before April 2024. Mechanical (including fracture toughness, hardness, modulus of elasticity, frictional resistance, slot accuracy, torque transmission, and shear bond strength) and clinical (including treatment efficiency and duration, cost, and comfort) properties were compared between traditional and customized orthodontic bracket systems in the current review. Our findings suggest that customized brackets have the potential to increase bracket slot precision, reduce treatment time, and offer cost-efficiency. However, it is worth noting that the advantages and disadvantages of customized bracket systems vary depending on the bracket material and the manufacturing methods, warranting comprehensively controlled investigations in the future.

5-(hydroxymethyl)furfural (HMF) is a key biomass derived platform chemical used to produce fuel precursors or additives and value-added chemicals, synthesised by the cascade isomerisation of glucose and subsequent dehydration of reactively formed fructose to HMF over Lewis and Bronsted acid catalysts, respectively. Zirconia is a promising catalyst for such reactions; however, the impact of acid properties of different zirconia phases is poorly understood. In this work, we unravel the role of the zirconia crystalline phase in glucose isomerisation and fructose dehydration to HMF. The Lewis acidic monoclinic phase of zirconia is revealed to preferentially facilitate glucose isomerisation, while the nanoparticulate tetragonal phase possesses Brønsted acid sites which favour fructose dehydration. Synergy between both zirconia phases facilitates cascade HMF production, with both catalysts investigated as physical mixtures in batch and flow reactor configurations. Using a physical mixture of only 15 wt % m-ZrO 2 with 85 wt % t-ZrO 2 in either batch or packed bed reactor configuration is sufficient to reach equilibrium conversion of glucose for subsequent dehydration by the t-ZrO 2 component. Under continuous flow, a six-fold increase in HMF production was obtained when operating with a physical mixture of m- and t-ZrO 2 compared to that from a single bed of t-ZrO 2., (© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Purpose: The peri-implant region, where restoration interfaces with mucosal tissue, plays an essential role in overall implant success and is just as important as osseointegration. The implant abutment materials are in intimate contact with human gingival fibroblasts (HGFs). This study compares the proliferation of HGFs between zirconia and titanium abutments used in dental implants., Methods: An electronic search was performed using PubMed, EMBASE, and Web of Science databases. English articles based on in vitro studies testing HGFs proliferation on zirconia and titanium implant abutment materials were included. A quality assessment of the selected study was performed using the web-based Science in Risk Assessment and Policy (SciRAP) tool. The HGFs proliferation and cellular morphology tests on zirconia and titanium materials from the included studies were summarized, exploring the role of material surface characteristics., Results: The electronic search yielded 401 studies, of which 17 were selected for inclusion. Zirconia exhibited comparable or superior efficacy in promoting the proliferation of HGFs compared to titanium. Observations on cellular morphology showed similar outcomes for both materials. Establishing a definitive relationship between contact angle, surface roughness, and their influence on cellular response remains challenging due to the varied methodological approaches in the reviewed studies., Conclusion: Based on the findings of this systematic review, zirconia shows comparable reliability to titanium as an abutment material for HGFs proliferation, with comparable or superior HGFs proliferative outcomes., (© 2024 by the American College of Prosthodontists.)

Background: Self-adhesive resin cements (SARCs) are widely used for fixed prostheses, but incomplete cleaning near the gingival margin can cause inflammation. However, the factors influencing cement properties and the biological response of gingival fibroblasts to cement eluates are not well understood. This study examines the impact of two light-polymerizing units (LPUs) on the physical and chemical properties of two SARCs under simulated clinical conditions, as well as the subsequent response of human gingival fibroblasts (hGFs) to these eluates., Methods: Dental cement discs of SARCs were polymerized using Kerr DemiPlus and 3 M Elipar DeepCure-S LED LPUs with or without a 2-mm thick zirconia screen. Physical properties (microhardness, surface roughness, residual monomers) were evaluated. hGFs' cell viability, wound healing potency, and gene expression were assessed., Results: Both Maxcem and RelyX exhibited reduced microhardness and increased surface roughness when polymerized through zirconia or with DemiPlus LPU. Higher residual monomers (HEMA and GDMA in Maxcem; TEGDMA in RelyX) concentration was observed with DemiPlus and zirconia polymerization. Maxcem polymerized with DemiPlus exhibited lower cell viability, impaired healing, and altered gene expression in hGFs compared to those polymerized with Elipar LPU. Gene expression changes included downregulated NRF2 and HO-1 and upregulated CCR-3., Conclusions: Light-polymerizing Maxcem through zirconia with DemiPlus LPU compromised SARCs' properties, leading to higher residual monomers and negatively impacting hGFs' viability, healing, and gene expression. Careful material selection and polymerization techniques are crucial to minimize adverse effects on surrounding tissues., Clinical Significance: Clinicians should exercise caution when using LPUs and SARCs, especially when polymerizing through zirconia. This will help optimize the physical and chemical properties of SARCs and minimize potential adverse effects on the surrounding gingival soft tissues., (© 2024. The Author(s).)