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Purpose: To compare abutment screw loosening in 24-degree angulation-correcting and straight implants subjected to nonaxial cyclic loading. Materials and Methods: Seven external connection 24-degree angulation-correcting implants (AI) and seven external connection straight implants (SI) were embedded in acrylic resin within a brass housing. A hemispherical titanium fatigue abutment was secured to each implant using a titanium abutment screw tightened to 32 Ncm. Each implant-abutment complex was positioned within a tooth wear machine and subjected to 1,000,000 cycles of 50-Ncm nonaxial loading to simulate 1 year of function. The abutment screw removal torque values were measured before and after cyclic loading, and the differences were statistically analyzed using two-way ANOVA and post hoc pairwise Dunn tests. Scanning electron microscopy and finite element analyses were performed to assess the wear of the abutment screws. Results: The mean torque loss for the AI group was 21.44% (P < .001) compared to 24.56% (P < .001) for the SI group. There was a statistically significant difference between the AI and SI groups (P = .006). Conclusions: Both groups exhibited significant abutment screw loosening. Within the limitations of this study, 24-degree angulation-correcting implants resisted screw loosening significantly more than straight implants. [ABSTRACT FROM AUTHOR]

After traumatic brain injury, the brain extracellular matrix undergoes structural rearrangement due to changes in matrix composition, activation of proteases, and deposition of chondroitin sulfate proteoglycans by reactive astrocytes to produce the glial scar. These changes lead to a softening of the tissue, where the stiffness of the contusion core and peripheral pericontusional regions becomes softer than that of healthy tissue. Pioneering mechanotransduction studies have shown that soft substrates upregulate intermediate filament proteins in reactive astrocytes; however, many other aspects of astrocyte biology remain unclear. Here, we developed a platform for the culture of cortical astrocytes using polyacrylamide (PA) gels of varying stiffness (measured in Pascal; Pa) to mimic injury-related regions in order to investigate the effects of tissue stiffness on astrocyte reactivity and morphology. Our results show that substrate stiffness influences astrocyte phenotype; soft 300 Pa substrates led to increased GFAP immunoreactivity, proliferation, and complexity of processes. Intermediate 800 Pa substrates increased Aggrecan+, Brevican+, and Neurocan+ astrocytes. The stiffest 1 kPa substrates led to astrocytes with basal morphologies, similar to a physiological state. These results advance our understanding of astrocyte mechanotransduction processes and provide evidence of how substrates with engineered stiffness can mimic the injury microenvironment.

Purpose: The purpose of this study was to investigate the mechanical properties of acrylic resins at different aging times for denture bases manufactured using the conventional method, microwave processing, milling, and 3D printing. Materials and Methods: A total of 160 rectangular samples (64 × 10 × 3.3 ± 0.03 mm) were prepared, divided among the four main resin groups, and subdivided into four analysis times (T0, T1, T2, and T3), resulting in 10 samples per subgroup. The samples were stored in distilled water at 37° ± 2°C for 24 hours (T0), then subjected to thermocycling at temperatures of 5° ± 1°C and 55° ± 1°C in different numbers of cycles: 5,000 (T1); 10,000 (T2); and 20,000 (T3). The mechanical properties evaluated were surface microhardness, flexural strength, and modulus of elasticity. Statistical differences between resin groups and aging time were evaluated using two-way analysis of variance (P < .05). Results: The 3D-printed resin showed the significantly lowest values of microhardness, flexural strength, and modulus of elasticity compared to other resins (P < .001). Conclusions: The CAD/CAM--milled denture resin showed mechanical properties similar to those of traditional resins (conventional and microwave-processed). The 3D-printing resin did not show adequate mechanical properties for long-term clinical use. Despite this, new studies are developing better properties of this resin for long-term use. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the usefulness of ridge augmentation using a customized titanium mesh (CTM) that was preformed by trimming and bending the commercial titanium mesh on a virtually reconstructed 3D acrylic resin model using clinical, radiologic, histologic, and histomorphometric analyses. Materials and Methods: This study was designed prospectively for patients who required vertical ridge augmentation using a staged approach before implant surgery. After installation of the CTM, grafting was performed using deproteinized porcine bone mineral covered with an absorbable membrane. Computed tomography was performed preoperatively and 6 months after simultaneous/staged guided bone regeneration to measure planned, reconstructed, and lacking bone volume, and the reconstruction rate was calculated based on these values. Clinical complications were also recorded, particularly the mesh exposure rate. At re-entry, the bone core was obtained using a trephine bur, and histologic and histomorphometric analyses were performed. Results: A total of 10 sites in eight patients were used for the study analysis. The mean planned bone volume was 1.15 cm3 (range: 0.78 to 1.56 cm3), mean lacking bone volume was 0.13 cm3 (range: 0 to 0.59 cm3), and mean reconstructed bone volume was 1.02 cm3 (range: 0.56 to 1.43 cm3). The exposure rate was 30% (3 out of 10 sites). The reconstruction rate was over 80%, except for one case that showed suppuration. From histomorphometric analysis, 27.52% ± 16.87% of new bone, 7.62% ± 5.19% of residual graft, and 64.86% ± 23.76% of connective tissue were observed. The core biopsy samples demonstrated different pseudoperiosteum layer appearances based on the healing stage of the augmented sites. In the premature bone, the inner osteogenic layer consisted of multiple layers of osteoblast cells with adjacent large blood vessels. However, in the mature augmented site, there was no specific inner osteogenic layer, and the outer fibrous layer was dominant. Conclusions: The fabrication of CTM based on the application of the 3D-printing technique makes vertical ridge augmentation easier and can reduce complications and achieve target bone acquisition. In addition, it is expected that quantitative analysis of the pseudoperiosteum layer will be facilitated using the CTM. [ABSTRACT FROM AUTHOR]

Purpose: To identify the most effective protocol for bonding denture bases and artificial teeth made with different computer-aided design and manufacturing (CAD/CAM) materials (milled and 3D-printed) and conventional heat-polymerized resins. Materials and Methods: This review was performed according to the Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA) criteria and registered in the International Prospective Registry of Systematic Reviews PROSPERO (CRD42021276084). An electronic search was performed independently by two examiners in PubMed/MEDLINE, Cochrane Library, Scopus, Web of Science, ProQuest, and OpenGrey databases for articles published up to and including December 2021. Results: The electronic search returned 806 articles, and after duplicates were removed, 589 articles remained. Four articles met the eligibility criteria to be included in this study. After evaluating the different combinations of denture base materials and artificial teeth, it was found that IvoBase CAD Bond (Ivoclar Vivadent) was effective for bonding CAD/CAM denture bases to prefabricated acrylic resin teeth, which showed no differences compared to the heat-polymerized resin denture base bonded to prefabricated acrylic resin teeth (2: 68.56; I2: 96%; P < .001). Conclusions: The IvoBase CAD Bond bonding system can be used for the fabrication of CAD/CAM denture bases with prefabricated acrylic resin teeth. [ABSTRACT FROM AUTHOR]

Purpose: To present prosthetic complications observed in the medium and long term in patients treated with metal-acrylic resin implant-supported fixed complete dentures (MAIFCDs). Materials and Methods: A total of 87 patients who were treated with MAIFCDs were included. Acrylic resin (denture teeth and base) fracture, screw loosening (prosthetic or abutment), screw (prosthetic or abutment), and framework fracture were analyzed for descriptive statistics. Product-limit survival estimates were used for the cumulative no-complication rate (CNCR) of prostheses. All results were assessed using a = .05. Results: The average observation time was 42.9 months (range: 19 to 153). Of 597 implants, 8 mandibular (44.4%) and 10 maxillary implants (55.6%) failed. In total, 29 patients (33.3%) experienced no complications in an average of 7 years, and 58 patients (66.6%) experienced at least one complication. The average time for the first complication to occur was 23 months (range: 1 to 97 months). The average number of complications was 5.9/patient. Acrylic resin complications were the most frequent, followed by screw loosening, screw fracture, and framework fracture. Of those patients with complications, 9 (16%) had maxillary MAIFCDs with an average of 4 complications. In total, 28 patients (48%) had only mandibular MAIFCDs with an average of 5 complications, and 21 patients (36%) had both arches treated with MAIFCDs with an average of 9 complications. Mandibular MAIFCDPs in women had a higher CNCR compared to maxillary MAIFCDs of both women and men and when both arches of women were treated with MAIFCDs (P < .05). Conclusions: The CNCR of MAIFCDs differed depending on the arch treated and sex. Mandibular MAIFCDs in women had a lower complication rate than MAIFCDs in other arch-sex pairs. Acrylic resin related complications were commonly observed as well as prosthetic screw loosening. [ABSTRACT FROM AUTHOR]

Immediate full-arch loading is a highly complex and techniquesensitive procedure. Digital impression techniques aim to replace conventional analog systems to carry out dental treatments in a more predictive, safer, and less time-consuming way. This case report describes a patient with a guarded periodontal prognosis, who was rehabilitated with implant-supported fixed prostheses after full-mouth extractions. Immediate full-arch loading was performed by means of two digital impression systems: photogrammetric technology with PIC dental in the maxillary arch, and MedicalFit in the mandible. Immediate provisional prostheses in acrylic resin (polymethyl methacrylate) were milled and placed within 12 hours after implant placement surgeries. Both provisional structures fitted properly providing adequate esthetics and function. After the implant osseointegration period, final digital impressions were registered, and definitive zirconia full-arch implant-supported prostheses were delivered. The 24-month follow-up did not show biologic or mechanical complications. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the applica.on of chitosan as a cleanser in the control of biofilm forma.on on cobalt-chromium (Co-Cr) alloy and acrylic resin surfaces. Materials and Methods: In total, 172 Co-Cr discs and 172 acrylic resin discs (14 mm x 3 mm) were contaminated with Streptococcus mutans, Staphylococcus aureus, Candida albicans, or Candida glabrata and incubated for 48 hours. Then, specimens were randomly divided into groups and immersed in the following solu.ons for 15 minutes: solu.on without chitosan (WC/control); chitosan solu.on (CH: 5 mg/mL); chitosan nanopar.cle solu.on (CN: 3.8 mg/mL); and effervescent tablet (ET). Biofilm recovery rates (n = 9) were evaluated by coun.ng the colony-forming units (CFU/mL). Biofilm morphology was evaluated using scanning electron microscopy (SEM). Data were compared using the Kruskal-Wallis or ANOVA tests followed by the Tukey post hoc test. Results: For acrylic resin, ET showed the lowest number of CFU for S aureus and S mutans (P < .001). CH exhibited intermediate values for S mutans, S aureus, and C albicans; CN exhibited intermediate values for S mutans and S aureus. For C glabrata, there was no sta.s.cal difference between the solu.ons (P = .264). For Co-Cr, ET showed the highest level of an.microbial ac.on against all microorganisms (P < .001), and CH showed an intermediate level of ac.on against S mutans and S aureus. Against C albicans and C glabrata, there was no significant difference among CH, CN, and WC. Conclusions: Although ET had a broader spectrum of an.microbial ac.on, CH showed promise as a denture cleanser. [ABSTRACT FROM AUTHOR]

A natural extract, i.e., urushiol, was employed to effectively cross-link and modify commercial wet-cured polyurethane acrylic resin. Comprehensive characterization of the paint film was performed using techniques such as FTIR, SEM, and TGA. The results indicated that the incorporation of urushiol significantly increased the cross-linking density of the resin, which in turn enhanced the film-forming properties, mechanical strength, and thermal stability of the paint film. Additionally, the study discovered that under isothermal conditions, the dynamic moduli (G′ and G″) of the paint film are related to the gel point frequency by a power law, aligning with the predictions of percolation theory. The application of the autocatalytic model has provided a novel approach to studying non-isothermal kinetic reactions, offering valuable insights for process optimization and further development of urushiol-based polyurethane. [ABSTRACT FROM AUTHOR]

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

Objective: This study proposed to assess the effect of Cryptocarya moschata extract on single and mixed biofilms formed on denture base and reline acrylic resin. Materials and Methods: Single and mixed biofilms of Candida albicans and Streptococcus mutans were formed on the samples and treated with C. moschata extract; Nystatin solution at 100,000 IU/mL or Penicillin antibiotic solution at 100,000 IU/mL; or PBS solution. Antimicrobial activity was analyzed by counting colony‐forming units, metabolism assay, assessment of protein components of the biofilm matrix, and of cell viability using confocal laser scanning microscopy (CLSM). Data were submitted to ANOVA and Tukey's post‐test (α = 0.05). Results: Cryptocarya moschata extract reduced cell viability of C. albicans and S. mutans single and mixed biofilms formed on samples. For all types of biofilms in the C. moschata group, there was a log reduction of the biofilm, proven by the Alamar Blue assay. Analyzing the extracellular matrix protein components, groups treated with the extract exhibited a lower level of fluorescence compared to the PBS groups. Reduction in thickness biofilm and viable cells was perceptible in the C. moschata group when assessing through CLSM. Conclusion: Cryptocarya moschata extract reduced the single and mixed biofilms of C. albicans and S. mutans on acrylic resins. [ABSTRACT FROM AUTHOR]

This review aimed to investigate the literature systematically and answer the question "Does the processing method of organic and inorganic agents incorporated into PMMA influence antimicrobial activity and cytotoxicity?". This systematic review was registered in the OpenScience Framework (osf.io/7nc28) and PRISMA guidelines were followed. The study design (PICOS) framework applied was P = polymethylmethacrylate; I = incorporation of organic and inorganic antimicrobials; C = control group; O = antimicrobial activity and cytotoxicity; and S = experimental in vitro studies. A custom search strategy was performed in Embase, Scopus, PubMed, and Science Direct databases. Studies were selected according to eligibility criteria in two steps. The risk of bias was evaluated by Joanna Briggs Institute's quasi-experimental studies tool. A qualitative analysis of the data was performed addressing: incorporation and polymerization methods, antimicrobial activity, and cytotoxicity of organic and inorganic agents added into PMMA. From a total of 1959 results, 34 studies were included in this review. The 3 organic agents evaluated showed antimicrobial efficacy and 1 was cytotoxic. Of the 31 inorganics, 4 showed no antimicrobial activity, and 8 reduced cell viability. Processing methods influenced the results. The incorporation of organic and inorganic antimicrobial agents into PMMA, depending on the processing method, changes the antimicrobial efficacy and cytotoxicity of the modified material. [ABSTRACT FROM AUTHOR]

Background: There is a lack of studies comparing the dimensional accuracy and color stability of denture base resins made using computer-aided design and computer-aided manufacturing (CAD-CAM) milling, 3-dimensional (3D) printing, and conventional denture processing techniques. This makes it challenging to determine the best method to fabricate complete dentures. The objective of this in vitro investigation was to assess and contrast the color stability and dimensional accuracy of denture base resins that were 3D printed and CAD-CAM milled, both before and after aging by thermocycling using digital surface matching technology and a benchtop laser scanner without using a spray, to optimize adaptation of the denture base and cast to minimize any imperfections and to evaluate the impact of the denture cleansing solution on the stability of color. Methods: Evaluation of the dimensional accuracy (n = 27) was completed on a sectional maxillary stone cast using a digital 3D-surface matching software before and after 5000 thermocycles. A spectrophotometer was used to measure the color change (△E00) of all disc specimens (N = 54) before and after 500 thermocycles and immersion in denture cleansing solution for 30 cycles (3 min each) daily for 6 days. The Kruskal Wallis test, Dunn's post hoc test, Tukey's test with Bonferroni adjustment, one sample t test and independent t test were used to statistically analyze the data (α < 0.05). Results: Thermocycling decreased the dimensional accuracy of the heat polymerized group at all 5 locations and the 3D-printed group at locations 1, 3 and 5 (P >.05), while it had no significant difference on the CAD-CAM milled group at all locations (P <.05). The color change (△E00) was lowest in the CAD-CAM milled group, moderate in the heat-polymerized group and highest in the 3D-printed group. After immersion in denture cleanser, the color change (△E00) was significantly higher in the 3 groups compared with after thermocycling (P >.001). Conclusions: CAD-CAM milled resins had the highest dimensional accuracy and the best color stability, conventional heat polymerized acrylic resins showed moderate change in dimensional accuracy and color stability, while the 3D- printed resin had the lowest dimensional accuracy and color stability after aging by thermocycling. [ABSTRACT FROM AUTHOR]

Background: Implant-retained obturators for maxillectomy cases have several advantages over traditional obturators but prosthetic design for specific conditions after maxillary resection has several challenges and the appropriate implant placement configuration is essential for improving retention and the stability of the implant-retained obturator. Objectives: The present study aimed to assess the retention force of using linear and nonlinear implant placement configurations using ball and socket attachment in implant-retained obturators at the initial retention and after simulation of six months of use. Materials and methods: Two identical epoxy resin maxillary models of a completely edentulous unilateral maxillary defect (Brown's class IIb) were used for implant placement, in the first model three implants were arranged with linear placement configuration, and in the second model three implants were arranged in nonlinear placement configuration. For proper sample sizing, 26 models and obturator were used. Two equal groups of obturators (13 for each group) were constructed, each with a different implant placement configuration. Both groups used the same attachment design (a non-splinted ball attachment). Using a cyclic loading machine that served as a dental insertion and removal simulator, each study group was subjected to 500 tension-compression cycles simulating 6 months of use. Using the universal testing machine, each obturator was removed at a speed of 50 mm/min for the crosshead. peak load to dislodgement was measured at the initial retention and after the simulations of six months of use. Data were analyzed using independent and paired t-tests while percent change was analyzed using the Mann Whitney U test. Results: There were a statistically significant differences in retention between the nonlinear implant placement configuration for Brown's class IIb maxillectomy and the linear implant placement configuration at initial retention evaluation with p-value of < 0.0001 and after simulation of six months of usage with p-value of < 0.0001 Also, after simulation of 6 months of use group I lose − 24.87 (10.16) % of its retention while group II lose − 17.49 (7.78) %. Conclusions: Non-linear implant placement is more retentive at the initial retention and after simulation of six months of use than linear and loses less retention after usage. [ABSTRACT FROM AUTHOR]

Hydrophobic deep eutectic solvents (HDESs) are a new generation of water-immiscible solvents that have shown potential as green and sustainable reaction media for biocatalytic applications. In this study, esterification of tyrosol and hydroxytyrosol catalysed by Novozym 435 (Candida antarctica lipase B immobilised on acrylic resin) was taken as a model reaction to examine the feasibility of using HDESs as solvents for acylation reactions and the impacts of the components and physicochemical properties of the HDESs on the enzymatic performance. 21 HDESs were screened. Yields as high as 95.1% could be achieved within 2 h of reaction in an HDES, comparable to or even better than the results obtained in organic solvents. The enzymatic reactions were favoured in the HDES comprising a tertiary alcohol instead of a secondary/ primary one as the hydrogen bond acceptor (HBA). Inverse correlations were found between enzyme activity and the polarity and viscosity of the HDES. Carboxylic acid-based eutectic solvents can play a dual role as both a reaction medium and a substrate reservoir for the acylation reaction. These findings provide valuable guidelines for selecting HDESs for biocatalytic applications. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to examine the shear bond strength (SBS) of repair material to conventionally, subtractive‐, and additive‐manufactured denture bases after different surface treatments. Materials and Methods: Disk‐shaped test specimens (N = 300) were prepared from denture base materials produced by one conventional (Procryla), one subtractive (Yamahachi), and one additive (Curo Denture) method. The test specimens were randomly divided into five groups (n = 10) and exposed to a variety of surface treatments—Group A: no surface treatment; Group B: grinding with silicon carbide paper; Group C: sandblasting; Group D: erbium: yttrium‐aluminum‐garnet laser; and Group E: plasma. Repair was performed with autopolymerizing acrylic resin (Meliodent). Surface roughness analyses were performed with a profilometer. Scanning electron microscopy was used to examine one specimen from each subgroup. SBS was evaluated on a universal testing machine. Failure types were observed under a stereomicroscope. Results: Surface roughness values were significantly higher in all test materials in Group D than in the other groups (p < 0.001). For conventional resin, the SBS values were higher in Group C than in Groups A, D, and E (p < 0.001). For CAD/CAM material, Groups B and C had significantly greater SBS increases compared with Group E (p < 0.001). For 3D material, Group D showed higher SBS than all groups except Group C (p < 0.001). Conclusions: For SBS, sandblasting was most effective in the conventional group, whereas laser treatment was the most effective in the additive‐manufactured group. For the subtractive group, surface treatments other than plasma exhibited similar SBS. Clinical Significance: In repairing fractured prostheses, any degree of roughening suitable for the material content may provide an SBS benefit. [ABSTRACT FROM AUTHOR]

Ideal prosthetic and aesthetic results in implant therapy results from successful implant placement. Such success depends on a number of factors; one of which is the accurate transfer of information from the planning stage to the surgical field. Surgical templates are instrumental in allowing such transfer of information. This article aims to review various designs of implant guides and their accuracy. CPD/Clinical Relevance: A surgical guide allows precise implant placement for predictable implant therapy outcomes. [ABSTRACT FROM AUTHOR]

Acrylic resins are one of the most important thermoplastic resins used in various industries due to their significant properties. However, they are inherently brittle and the addition of plasticizers to them is very common. In this study, the role of both Polyethylene Glycol (PEG) and Triacetin on the mechanical properties of acrylic resin has been investigated. To do so, tensile test, bending, and wear tests have been performed. To achieve the optimal mixture of plasticizers, a tensile test has been carried out, and the best percentage of the mixture has been determined. Subsequently, bending and wear tests were conducted, which showed a significant increase in the bending strength of the acrylic resin after the addition of plasticizers. Furthermore, it was found that the abrasion mechanism of the resin was significantly altered compared to its pure state. [ABSTRACT FROM AUTHOR]

The current study evaluates the effect of morpholine on saliva-contaminated acrylic resin repaired with light-cured resin composites. Sixty rods of self-curing acrylic resin were fabricated and assigned into four groups of fifteen specimens and surface-treated with saliva, phosphoric acid (PH), morpholine (MR), liquid MMA monomer, and a universal adhesive agent (UA, Singlebond Universal) based on the following techniques: group 1, saliva; group 2, saliva + PH + MMA + UA; group 3, saliva + MMA + UA; and group 4, saliva + MR + MMA + UA. An Ultradent model was placed at the center of the specimen, and then the resin composite was pressed and light-cured for 20 s. A mechanical testing device was used to evaluate the samples' shear bond strength (SBS) scores. The debonded specimen areas were inspected under a stereomicroscope to identify their failure mechanisms. The data were assessed by employing the one-way ANOVA approach, and the significance level (p < 0.05) was established with Tukey's test. The greatest SBS scores for group 2 (30.46 ± 2.26 MPa) and group 4 (32.10 ± 2.72 MPa) did not differ statistically significantly from one another. The lowest SBS recorded for group 1 was 1.38 ± 0.87 MPa. All of the fractured samples in group 1 had an adhesive failure profile. Groups 2 and 4 had the greatest percentages of cohesive failures. This study concluded that applying phosphoric acid and morpholine to sandblasted self-curing acrylic resin contaminated with saliva before MMA and universal adhesive agents are applied is the most efficient protocol for stimulating SBS when it is repaired with light-cured resin composites. [ABSTRACT FROM AUTHOR]

Background: Digitally fabricated dentures may require relining due to continual alveolar ridge resorption. However, studies evaluating the tensile bond strength (TBS) of digitally fabricated dentures bonded to denture liners are lacking. This study aimed to evaluate the TBS of autopolymerized, heat-polymerized, milled, and 3D printed denture base materials bonded to 2 acrylic-based and 2 silicone-based denture liners, both before and after thermocycling. Additionally, the impact of thermocycling on the TBS were also evaluated. Methods: The TBS of 4 different denture base materials (Palapress (PL), Vertex Rapid Simplified (VR), Smile CAM total prosthesis (SC), and NextDent denture 3D+ (ND)) bonded to 2 acrylic-based (GC Soft-Liner (GC) and Tokuyama Rebase II (RB)) and 2 silicone-based (Ufi Gel P (UP) and Sofreliner Tough M (ST)) denture liners were tested. Specimens (n = 8) were divided into non-thermocycling and thermocycling groups. Non-thermocycling specimens were tested after 24-hours water immersion, while thermocycling specimens were underwent 5000 cycle and were immediately tested. Mode of failure was examined under a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey HSD tests (α = 0.05), and independent samples t test (α = 0.05) for TBS between non-thermocycling and thermocycling groups. Results: For the non-thermocycling groups, within the same denture liner material, no significant differences were found between denture base materials, except the ND + RB group, which had significantly lower TBS. For the thermocycling groups, within the same denture liner material, the TBS in the PL group exhibited the highest and the ND group exhibited the lowest. Within the same denture base material, in both non-thermocycling and thermocycling groups, the TBS in the ST group exhibited the highest; in contrast, that in the GC group exhibited the lowest. No significant differences were observed in TBS between non-thermocycling and thermocycling groups, except for denture base materials bonded to the ST group, SC + UP, and ND + UP groups. Conclusions: Milled denture base can be relined with acrylic-based or silicone-based denture liner. However, cautions should be exercised when relining 3D printed denture base. Thermocycling did not affect TBS between acrylic-based denture liners and denture bases. In contrast, it affected the bond between silicone-based denture liner and denture base. [ABSTRACT FROM AUTHOR]

Since acrylate‐based materials are widely used in dentistry, their drawbacks such as low impact resistance and hardness, require continuous research in the field of materials science in order to avoid sudden fracture caused by chewing or fall. In this study, auto‐polymerizing poly(methyl methacrylate) (PMMA), commonly used as denture base material, was reinforced with poly(4‐styrenesulfonic acid‐co‐maleic anhydride) sodium salt (PSSMA) and strontium titanate (STO), with the aim of improving impact behavior and microhardness. Morphological analysis confirmed formation of phase‐separated and co‐continuous microscopic structures of PSSMA in PMMA, without visible agglomerates of STO nanoparticles, indicating that PSSMA‐STO interaction contributed to a better distribution of nanoparticles. Fourier transformed infrared spectroscopy revealed that PSSMA and STO did not interfere in the polymerization of methyl methacrylate. This was further supported by thermal analysis, which also showed that the addition of PSSMA and STO had no significant influence on thermal degradation. On the other side, PSSMA and STO significantly enhanced mechanical performance of PMMA. The modulus of elasticity increased by up to 48.6%, total absorbed impact energy improved by up to 108.4%, and microhardness increased by up to 272.8% when PSSMA was combined with STO for reinforcing denture PMMA. These results demonstrate the significant potential of PSSMA, which could be combined with other ceramic nanoparticles for denture reinforcement in the future. Highlights: This research presents novel dental hybrid composite.Influence of strontium titanate (STO) and poly(4‐styrenesulfonic acid‐co‐maleic anhydride) sodium salt (PSSMA) on poly(methyl methacrylate) (PMMA) was investigated.PSSMA/STO improved modulus of elasticity, microhardness and impact resistance.Sample with 5 wt% PSSMA and 1 wt% STO showed the highest improvement compared to PMMA.Presented hybrid composite could use as denture base material. [ABSTRACT FROM AUTHOR]

The aging failure process of acrylic resin (AR) coatings widely used in ship anti-corrosion systems is highly complex. Currently, there are no established models or methods for predicting the aging of AR coatings in different marine environments. Therefore, this study proposes a framework for predicting the aging of AR coatings in marine environment based on short-term indoor accelerated tests. Initially, a comprehensive aging evaluation method for AR coatings is developed by integrating three commonly used coating performance evaluation indicators (gloss, color difference, and electrochemical impedance) based on the Technique for Order Preference by Similarity to Ideal Solution. Subsequently, an aging severity index is defined to quantify the impact of different environments on the coating aging process. Following this, 14 sets of indoor accelerated aging tests for AR coatings under various environmental conditions are conducted. Based on the test results, a comparative analysis of the predictive performance of three environmental effect models, namely multiple linear regression model, generalized Eyring model, and genetic algorithm-back-propagation model, is performed. Finally, utilizing the environmental effect models and global marine environmental data, the aging severity index of AR coatings in global marine environments is predicted and extrapolated. [ABSTRACT FROM AUTHOR]

The continuous preparation scheme EPO-Poly-indol-nido-carborane (E-P-INDOLCAB), L100-55-Poly-indol-nido-carborane (L-P-INDOLCAB), RS-Polyindol-nido-carborane (S-P-INDOLCAB), and RL-Poly-indol-nido-carborane (R-P-INDOLCAB) were used to prepare the four types of acrylic resin-coated nido-carborane indole fluorescent polymers. After testing their spectral properties and the fluorescence stability curve trend at various acidic pH values (3.4 and 5.5, respectively), L-P-INDOLCAB and S-P-INDOLCAB were determined to be the best polymers. The stable states of the two polymers and the dispersion of the nanoparticles on the system's surface during Atomic Force Microscope (AFM) test are shown by the zeta potentials of -23 and -42 mV. The dispersion of nanoparticles on the system's surface and the stable condition of the two polymers were examined using zeta potential and atomic force microscopy (AFM). Transmission electron microscopy (TEM) can also confirm these findings, showing that the acrylic resin securely encases the interior to forman eyeball. Both polymers' biocompatibility with HELA cells was enhanced in cell imaging, closely enclosing the target cells. The two complexes displayed strong inhibitory effects on PC-3 and HeLa cells when the concentration was 20 ug/mL, as validated by subsequent cell proliferation toxicity studies. [ABSTRACT FROM AUTHOR]

Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; microcapsules were produced and added to the UV coating to enhance its self-healing property, providing a good protection for both the UV coating and the substrate. UV primer microcapsules were prepared with UV primer as the core material and melamine formaldehyde resin as the wall material. The UV primer containing more than 98.0% solids content was mainly composed of epoxy acrylic resin, polyester acrylic resin, trihydroxy methacrylate, trimethyl methacrylate, and photo initiator. The preparation process of the UV primer microcapsules was optimized. Further, the UV coating was prepared with better UV primer microcapsules, and the effects of the UV primer microcapsules alongside the comprehensive properties of the coating were studied. The best preparation process for the UV primer microcapsules was as follows: the wall-core mass ratio was 1:0.50, Triton X-100 and Span-20 as emulsifiers with an HLB value of 10.04, the microcapsule reaction temperature was 70 °C, and the reaction time of the was 3.0 h. When the quantity of the UV primer microcapsules increased in the coating, color difference ΔE of the coating increased, gloss decreased, transmittance decreased, elongation at break increased and then decreased, roughness increased, and self-healing rate first increased and then decreased. When the addition of the UV primer microcapsules reached 2.0%, the color difference ΔE of the coating was 1.71, the gloss was 106.63 GU, the transmittance was 78.80%, the elongation at break was 3.62%, the roughness was 0.204 μm, and the self-healing rate was 28.56%, which were the best comprehensive properties of the UV primer. To improve the comprehensive properties of the UV coatings, the UV coatings were modified by a microcapsule technology, which gave the UV coatings a better self-healing property. The application range of microcapsules for the UV coatings was broadened. Based on the previous research of microcapsules in UV coatings, the results further refined the study of the effects of adding self-healing microcapsules to UV coatings using the UV coating itself as the core material. [ABSTRACT FROM AUTHOR]

Background: To evaluate the flexural strength of digitally milled and printed denture base materials. Methods: The materials tested were Lucitone 199 denture base disc (Dentsply Sirona), AvaDent denture base puck (AvaDent), KeyMill denture base disc (Keystone), Lucitone digital print denture base resin (Dentsply Sirona), Formlab denture base resin (Formlabs), and Dentca base resin II (Dentca). Sixty bar-shaped specimens of each material were prepared for flexural strength testing and were divided into five groups: control, thermocycled, fatigue cycled, and repair using two different materials. The flexural strength and modulus were tested using a 3-point bend test performed on an Instron Universal Testing Machine with a 1kN load cell. The specimens were centered under a loading apparatus with a perpendicular alignment. The loading rate was a crosshead speed of 0.5 mm/min. Each specimen was loaded with a force until failure occurred. A one-way ANOVA test was used to analyze the data, followed by Tukey's HSD test (α = 0.05). Results: The milled materials exhibited higher flexural strength than the printed materials. Thermocycling and fatigue reduce the flexural strengths of printed and milled materials. The repaired groups exhibited flexural strengths of 32.80% and 30.67% of the original flexural strengths of printed and milled materials, respectively. Nevertheless, the type of repair material affected the flexural strength of the printed materials; the composite resin exhibited higher flexural strength values than the acrylic resin. Conclusions: The milled denture base materials showed higher flexural strength than the printed ones. [ABSTRACT FROM AUTHOR]

Background: Patients tend to favor the whitening mouthwashes as they are easily applied and affordable. This study aimed to evaluate the effect of hydrogen peroxide versus charcoal-based whitening mouthwashes on color, surface roughness, and color stability of enamel. In the current study, the whitening mouthwashes used have the ability to stop future stains due to their white seal technology. Methods: A total of 21 permanent central incisor teeth extracted for periodontal reasons were used in the present study. Teeth roots were sectioned and crowns were mounted in self-cured acrylic resin blocks. The specimens were randomly divided into three groups (n = 7) according to the tested whitening mouthwash: Control group ‟ DW" (Distilled water), ‟OW" group: Peroxide-based mouthwash (Colgate Optic White) and ‟CP" group: Charcoal-based mouthwash (Colgate® Plax Charcoal). Regarding ‟OW" and ‟CP" groups, the specimens were immersed in 20 ml of the tested mouthwash in each corresponding group for 1 min twice daily (morning and evening) for a total of 12 uninterrupted weeks. Color change was assessed using VITA Easyshade spectrophotometer and surface roughness (Ra) was measured using a white light interferometer. The specimens were stained using black tea solution and color was measured after 24 h of immersion for assessment of color stability. Results: Color change results revealed that both whitening mouthwashes were able to restore color comparable to the control group with no significant difference between them. Regarding surface roughness, the control group showed the highest mean Ra value, followed by ‟OW" group while ‟CP" group showed the lowest mean Ra value. While color stability after staining, the control group showed a significantly higher value than the ‟CP" and ‟OW" groups. Conclusion: Hydrogen peroxide and charcoal-based whitening mouthwashes improve the color of enamel with no adverse effect on the surface roughness. Both whitening mouthwashes were beneficial to maintain the color after staining and prevent future enamel stains. [ABSTRACT FROM AUTHOR]

Objectives: To assess the feasibility of producing 3D‐printed intracoronal restorations, thin and ultrathin veneers, and to compare their mechanical behavior, accuracy, biological, and stain susceptibility to the currently applied milled restorations. Materials and Methods: The databases were comprehensively searched for relevant records up to January 2024 without language restrictions. All studies that assessed 3D‐printed partial coverage restorations including inlays, onlays, laminate, and occlusal veneers were retrieved. Results: The web search yielded a total of 1142 records, with 8 additional records added from websites at a later stage. Only 17 records were ultimately included in the review. The included records compared 3D‐printed; alumina‐based‐ and zirconia ceramics, lithium disilicate ceramics, polymer infiltrated ceramics, polyetheretherketone (PEEK), resin composites, and acrylic resins to their CNC milled analogs. The pooled data indicated that it is possible to produce ultrathin restorations with a thickness of less than 0.2 mm. 3D‐printed laminate veneers and intracoronal restorations exhibited superior trueness, as well as better marginal and internal fit compared to milled restorations (p < 0.05). However, it should be noted that the choice of materials and preparation design may influence these outcomes. In terms of cost, the initial investment and production expenses associated with 3D printing were significantly lower than those of CNC milling technology. Additionally, 3D printing was also shown to be more time‐efficient. Conclusions: Using additive manufacturing technology to produce restorations with a thickness ranging from 0.1 to 0.2 mm is indeed feasible. The high accuracy of these restorations, contributes to their ability to resist caries progression, surpassing the minimum clinical threshold load of failure by a significant margin and reliable adhesion. However, before 3D‐printed resin restorations can be widely adopted for clinical applications, further improvements are needed, particularly in terms of reducing their susceptibility to stains. Clinical Significance: 3D‐printed intracoronal restorations and veneers are more time and cost‐efficient, more accurate, and could provide a considerable alternative to the currently applied CNC milling. Some limitations still accompany the resin materials, but this could be overcome by further development of the materials and printing technology. [ABSTRACT FROM AUTHOR]

Most of the artworks stored in museums are often kept in inappropriate climatic and environmental conditions that facilitate the formation and growth of microorganisms, such as fungi, which are responsible for many types of biodegradation phenomena. To mitigate and prevent these deteriorative processes, functionalized packaging materials can be used for the storage and handling of artworks. The aim of this study was to develop a potential anti-biodeterioration coating suitable for packaging purposes. TiO2 and ZnO doped with different amounts of Ag (0.5 wt%, 1 wt%, and 3 wt%) were synthesized and dispersed in polyvinyl alcohol (PVA) and acrylic resin (Paraloid B72), then applied on different types of packaging materials (cellulose and the high-density spunbound polyethylene fiber Tyvek®, materials that are frequently used as packaging in museums). Analytical investigations (SEM/EDS, Raman, FTIR, and XRD) were employed to assess dispersion on the packaging material. Furthermore, resistance against biodeteriogens was assessed using Cladosporium sp., a bioluminometer, to define the biocidal efficacy. [ABSTRACT FROM AUTHOR]

The cellular mechanisms of burn conversion of heat damaged tissue are center of many studies. Even if the molecular mechanisms of heat-induced cell death are controversially discussed in the current literature, it is widely accepted that caspase-mediated apoptosis plays a central role. In the current study we wanted to develop further information on the nature of the mechanism of heat-induced cell death of fibroblasts in vitro. We found that heating of human fibroblast cultures (a 10 s rise from 37 °C to 67 °C followed by a 13 s cool down to 37 °C) resulted in the death of about 50% of the cells. However, the increase in cell death started with a delay, about one hour after exposure to heat, and reached the maximum after about five hours. The lack of clear evidence for an active involvement of effector caspase in the observed cell death mechanism and the lack of observation of the occurrence of hypodiploid nuclei contradict heat-induced cell death by caspase-mediated apoptosis. Moreover, a dominant heat-induced increase in PARP1 protein expression, which correlated with a time-delayed ATP synthesis inhibition, appearance of double-strand breaks and secondary necrosis, indicate a different type of cell death than apoptosis. Indeed, increased translocation of Apoptosis Inducing Factor (AIF) and Macrophage Migration Inhibitory Factor (MIF) into cell nuclei, which correlates with the mentioned enhanced PARP1 protein expression, indicate PARP1-induced, AIF-mediated and MIF-activated cell death. With regard to the molecular actors involved, the cellular processes and temporal sequences, the mode of cell death observed in our model is very similar to the cell death mechanism via Parthanatos described in the literature. • Results contradict heat-induced cell death by caspase-mediated apoptosis. • Results indicate a different heat induced cell death of fibroblasts than apoptosis. • Results indicate a heat-induced cell death via Parthanatos. [ABSTRACT FROM AUTHOR]

This work aims to demonstrate the effect of ZrO 2 and MgO inclusion into the Poly(methyl methacrylate) (PMMA). To fabricate novel hybrid composites via heat cure method, various composites (PZM2, PZM4 and PZM6) were synthesized in the system [(95-x) PMMA + 5 ZrO 2 + x MgO] (x = 2, 4, and 6) respectively. Density of the prepared composites were determined and varying between 1.035–1.152 g/cm3. X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) followed by EDAX and mechanical testing were performed to evaluate the fabricated composite properties. Moreover, to explore the structure of the fabricated composites the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR Spectrum were recorded which clarify chemical shifting and motional dynamics of the composites. Mechanical tests were performed by UTM and the obtained parameters such as compressive strength, Young's modulus, fracture toughness, brittleness coefficient, flexural strength and flexural modulus are found to be in the range of 91–100 MPa, 0.48–0.51 GPa, 9.122–9.705 MPa.m1/2 , 0.66–0.815, 51.03–42.78 MPa and 499–663 MPa respectively. Some more mechanical parameters such as proportional limit, elastic limit, failure strength, modulus of resilience and modulus of toughness were also calculated. Furthermore, tribological properties were also determined and the coefficient of friction (COF) was decreased by 17.4 % and 38 % for composite PZM6 at 20 N and 40 N as compared to the composite PZM2 and the lowest wear volume of 1.55 mm3 was observed for PZM2, whereas the maximum volume loss of 5.64 mm3 is observed for composite PZM6. To check out the biocompatibility, cytotoxicity and genotoxicity of the fabricated composites the Trypan-blue assay was also performed for PZM2 and PZM6 composites. Dissection on the gut of larvae was also performed on the both composites followed by DAPI and DCFH-DA staining. Therefore, these synthesized samples can be used for the fabrication of denture materials. [Display omitted] • Synthesis of ZrO 2 and MgO reinforced denture-based resin composites via heat cure method. • Density of the composites were determined and varying between 1.035-1.152 g/cm3. • The structure of the fabricated composites was studied using the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR spectrum. • The PZM6 composite shows the maximum compressive strength, 100 MPa. • To check out the biocompatibility, cytotoxicity and genotoxicity, the Trypan-blue assay was performed. [ABSTRACT FROM AUTHOR]

Aims: To investigate the efficiency and abrasiveness of air‐polishing on different types of denture base acrylic resins and whether air‐polishing can be an effective technique to clean dentures chairside. Materials and Methods: A total of 60 specimens were prepared (n = 20/group); heat‐polymerized polymethyl methacrylate (PMMA) (G1), subtractive manufacturing (SM) (G2) and additive manufacturing (AM) denture base resins (G3). Equal number of specimens in each group were stained with permanent marker or nail polish and pumice mixture to mimic calcified biofilm. All specimens were treated using EMS Airflow® Prophylaxis Master with two different powders; erythritol or sodium bicarbonate powder, following manufacturer instructions. Efficacy of the powders and surface roughness of the specimens were measured. Scanning electron microscopy imaging was captured for qualitative observation. Results: The highest efficacy for stain removal was found in erythritol powder on G1 (98.06% ± 1.304%). The lowest was found in the erythritol powder on G3 (91.83% ± 3.611%). The highest efficacy for biofilm removal was found in sodium bicarbonate powder on G3 (71.49% ± 8.607%), and the lowest was found in erythritol powder on G2 (11.64% ± 4.68%). Only AM resins had statistically significant increases in surface roughness with the use of erythritol powder (p < 0.001). The use of sodium bicarbonate powder significantly increases surface roughness of heat‐polymerized (p < 0.025) and AM resins (p < 0.724). Conclusions: Air‐polishing technology has shown to be effective and suitable for cleaning dentures. The sodium bicarbonate powder showed superior efficacy in cleaning dentures compared to the erythritol powder. Both powders show varyingly increase roughness depending on denture resin. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluates and compares the effect of printing layer thickness (LT) and post-polymerization time (PPT) on the flexural strength and hardness of three 3D-printed resins after thermal aging. Methods: A bar shape (64 × 10 × 3.3 mm) and a disc shape (15 × 2 mm) were designed for flexural strength and hardness testing, respectively. ASIGA, NextDent, and FormLabs 3D-printed resins were used to print specimens with different LTs (25 µm, 50 µm, and 100 µm). Each thickness group was post-polymerized (PP) for different times (15, 30, 60, and 90 min). All printed specimens were thermally cycled (5000 cycles) and then tested, measuring the flexural strength and hardness using a universal testing machine and Vickers hardness tester, respectively. The data were analyzed using ANOVA and a post hoc Tukey's test (α = 0.05). Results: A PPT of 90 min showed the highest flexural strength. In comparisons of the LTs, 25 µm and 50 µm significantly increased flexural strength compared with 100 µm, which showed the lowest value for each PPT. The hardness increased as the PPT increased for all materials. In our LT comparison, 25 µm and 50 µm significantly increased the hardness for NextDent and FormLabs resins, while only 25 µm showed high hardness compared with 50 µm and 100 µm for ASIGA. Conclusion: Both parameters (LT and PPT) impact flexural strength and hardness. Increased PPT with the minimum LT is recommended. [ABSTRACT FROM AUTHOR]

This study aims to compare the incidence of biologic and mechanical complication rates and the survival rates after at least 5 years of implants and implant-supported fixed complete dental prostheses (IFCDPs) placed during second-stage surgery using four and six implants. A total of 77 patients (33 men, 44 women) with a mean age of 60.6 ± 8.8 years (range: 39 to 80 years) were included, and the total of 92 IFCDPs were classified into two groups: 51 received four implants, and 41 received six implants. No implant failed in the four-implant group (0/204), and one implant failed in the six-implant group (1/246), with no statistically significant differences (P > .05). One prosthetic failure occurred in the four-implant group (1/51), and one failure occurred in the six-implant group (1/41). Both groups experienced some technical and biologic complications, with no statistically significant differences between the groups (P > .05). For both groups, veneer or resin fracture was the most frequent mechanical complication, and mucositis was the most frequent biologic complication. The use of four or six implants may represent a predictable treatment option in the rehabilitation of completely edentulous patients with IFCDPs in the medium-term. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate differences in the temperature rise at the cervical area of one-piece vs two-piece implants during the setting of relined provisional crowns. Materials and Methods: A K-type thermocouple was fixed to the coronal thread of 15 one-piece implants and 15 two-piece implants that were mounted on a plexiglass apparatus. Baseline temperature (Bl Temp) was recorded before starting the curing process. The maximum temperature (Max Temp) reached during the process in both implant groups was also recorded. Total heat flux (THF) was calculated as well as the thermal amplitude (Temp-Amp) at the implant surface. Finally, the differences between the implant types were compared using unpaired t test. Results: The increase in temperature from baseline was statistically significantly greater in the one-piece implants than in the two-piece implants (P < .01). Similarly, the THF and Temp-Amp were significantly greater in the one-piece implants compared to two-piece implants (P < .01). Conclusions: The polymerization of PMMA-based resin temporary crowns produces a significant temperature rise in both one-piece and two-piece implants. It is advisable to use two-piece implants to restore immediately loaded implants to reduce the risk to implant surroundings that may occur due to the temperature rise at the implant neck. [ABSTRACT FROM AUTHOR]

Purpose: To determine which clinical factors might affect the postimplantoplasty presence of residual threads, platform alterations, and level of surface roughness. Materials and Methods: A total of 60 implants were placed in 20 resin models (10 edentulous maxillary models and 10 partially dentate mandibular models), and 5-mm peri-implant bone defects were created. These models were then placed in simulation mannequins. A single researcher performed the implantoplasties, which were divided into the following groups: favorable situation (FS; maxillary incisors without adjacent teeth), unfavorable situation (US; mandibular molars with adjacent teeth), crown (C; mandibular premolars with a prosthetic crown and adjacent teeth), and noncrown (NC; mandibular premolars with adjacent teeth and without a prosthetic crown). The presence of residual threads, gaps in the implant-abutment interface, and silicone debris was assessed using a scanning electron microscope (SEM), and the surface roughness (Sa and Sz) was analyzed with a confocal optical microscope. A descriptive and bivariate analysis was conducted. Results: The postimplantoplasty surfaces were significantly smoother than the original implant surfaces. The surface roughness was significantly higher in the US group than in the FS group. Gaps in the implant-abutment interface were infrequent (6.67%; 95% CI = 2.62 to 15.93) and only appeared in the posterior zone. The odds ratio for the presence of residual threads and silicone debris (US group vs FS group) was 7.1 (95% CI = 4.15 to 12.14; P < .001) and 5.53 (95% CI = 3.21 to 9.53; P < .001), respectively. When a prosthetic crown was present, residual threads were 7 times more likely to be found (OR = 7.0; 95% CI = 3.5 to 13.99; P < .001). Conclusions: Implantoplasty leads to a significant reduction in the surface roughness of implants but is affected by several variables. Performing implantoplasty on posterior mandibular implants with adjacent teeth seems to be more challenging compared to implants placed in the anterior region of a fully edentulous maxilla. The presence of a prosthetic crown should also be considered as a relevant factor. Furthermore, implantoplasty can sometimes cause gaps in the implant-abutment interface and an accumulation of silicone debris, especially in areas with limited access. [ABSTRACT FROM AUTHOR]

Objective: The present study aimed to assess the clinical and radiographic effect of a bone graft material (β-tricalcium phosphate + hydroxyapatite) alone and in combination with platelet-rich fibrin in intrabony defects of periodontitis patients. Method and materials: This 6-month randomized controlled clinical trial was carried out in 42 intrabony periodontal defects (average age 40 years). Intrabony defects ≥ 3 mm along with associated probing depth of ≥ 5 mm following phase 1 periodontal therapy were treated either with open flap debridement with bone graft (β-tricalcium phosphate + hydroxyapatite; control group) or open flap debridement with bone graft plus platelet-rich fibrin membrane (test group). Individual customized acrylic stents with grooves were used to ensure reproducible and repeatable measurements of clinical and radiographic parameters, including probing pocket depth (PPD), relative clinical attachment level (RCAL), gingival marginal level (GML), vertical bone defect fill (VHD), and area of intrabony defects (AOD) on intraoral periapical radiographs. Clinical attachment level (CAL) gain was considered as primary outcome and PPD reduction and radiographic bone fill as secondary outcomes. Results: The preoperative Plaque Index, RCAL, GML, PPD, VHD, and AOD in the control group were 1.06 ± 0.08, 11.57 ± 2.29 mm, 5.24 ± 1.89 mm, 6.29 ± 1.52 mm, 14.36 ± 2.65 mm, and 7.79 ± 4.39 mm2, respectively. After 6 months these were 1.08 ± 0.14, 9.34 ± 2.54 mm, 5.81 ± 2.20 mm, 3.52 ± 0.93 mm, 12.64 ± 2.34 mm, and 5.34 ± 3.2 mm2, respectively. The preoperative PI, RCAL, GML, PPD, VHD, and AOD in the experimental group were 1.14 ± 0.05, 12.19 ± 2.86 mm, 4.38 ± 1.63 mm, 7.81 ± 2.6 mm, 13.46 ± 3.42 mm, and 10.31 ± 8.71 mm2, respectively. After 6 months these were 1.09 ± 0.12, 8.62 ± 2.62 mm, 4.90 ± 1.79 mm, 3.71 ± 1.68 mm, 10.10 ± 2.07 mm, and 4.38 ± 2.67 mm2, respectively. After 6 months of evaluation both the groups showed a significant reduction in PPD (P < .001) and a significant gain in CAL (P < .001), as well as significant improvement in radiographic VHD fill and AOD changes. Again, the test group showed significant changes (P < .001) over the control group considering the same outcomes. Conclusion: With the study limitations in mind, it can be concluded that for the treatment of intrabony defects with the bone graft material (β-tricalcium phosphate + hydroxyapatite; Biograft, IFGL Bio Ceramics) or the same bone graft with platelet-rich fibrin membrane results in statistically significant improvement in clinical (CAL and PPD) and radiographic (VHD and AOD) parameters, the latter having highly significant benefits. However, the bone graft material requires improvement. [ABSTRACT FROM AUTHOR]

This study compares the fracture strength of teeth restored with conventional round fiber post (CP) and bundle post (BP) in two different lengths. A total of 48 mandibular premolars were selected. Endodontic treatment was performed, and the premolars were divided into four groups (n = 12 per group): Group C9 = 9-mm CP; Group C5 = 5-mm CP; Group B9 = 9-mm BP; Group B5 = 5-mm BP. Post spaces were prepared, and posts were disinfected with alcohol. Silane was applied, and posts were placed with self-etch dual-cure adhesive. The core structures were created using dual-cure adhesive and standardized core-matrix. Specimens were embedded in acrylic, and the periodontal ligament was simulated with polyvinyl-siloxane impression material. Thermocycling was performed, and specimens were then loaded at a 45-degree angle to the long axis. The failure mode was analyzed with x5 magnification, and statistical analyses were performed. No statistical difference was found between post systems and post lengths (P > .05). Chi-square test revealed no statistical difference in the failure mode (P > .05). BP did not affect fracture resistance compared to CP. For the restoration of extremely irregular canals with a fiber post, BP can be used as an alternative system because it does not reduce the fracture strength. If necessary, longer posts can be used without decreasing the fracture resistance. [ABSTRACT FROM AUTHOR]

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Objective: Maintaining appropriate salivary levels of an active ingredient is challenging. Intraoral trays can be used to deliver medications for localized treatment. Based on previous successful daytime studies with a slow-release sirolimus varnish, the aim was to optimize intraoral appliances/trays for overnight use to deliver slow-release medications in a manner that maintains therapeutic salivary levels of the active ingredient to treat oral conditions. Method and materials: An acrylic tray appliance containing 0.5 mg of sirolimus in a sustained-release varnish was placed on six anterior teeth for 12 hours, in ten healthy volunteers. Whole unstimulated saliva was collected at 1, 2, 10, and 12 hours after application. Blood was collected at the time of recruitment to confirm eligibility, and 12 hours after device removal to measure sirolimus levels. Drug levels in the blood and saliva were analyzed. Slow- and fast-release formulations, varnish position (buccal, palatal, or lingual), and tray placement (mandibular or maxillary) were qualitatively compared. Participants evaluated the varnish and tray. Results: Moderate concentrations of sirolimus were detected in the saliva when the fast-release formulation was used. The highest levels were from the mandibular tray with lingual varnish application. Sialometry of all participants was within normal range, and the highest drug levels were detected when low flow was measured. No traces of the medication were found in the blood. Conclusions: Salivary concentrations of medications applied to an intraoral appliance are affected by the placement in the maxilla or mandible, varnish formulation, location of varnish, and salivation rate. These results may help optimize medication release following application to various oral devices. [ABSTRACT FROM AUTHOR]

Objective Materials and Methods Results Conclusions To evaluate the efficacy of recombinant psoriasin as a novel treatment for oral candidiasis by eliminating Candida albicans growth on polymethyl methacrylate denture base.Recombinant psoriasin protein was expressed and purified from E. coli, and Candida growth was monitored in vitro with varying concentrations of psoriasin. Subsequently, denture‐base polymethyl methacrylate was immersed in psoriasin's solution or voriconazole, and fungal growth on the acrylic base and in the medium was examined by scanning electron microscopy and optical density, respectively. Cellular viability of HeLa and human gingival fibroblast cells treated with psoriasin was measured by methylene blue assay.The findings reveal an effective antifungal activity of psoriasin, completely inhibiting Candida albicans growth in RPMI at a protein concentration above 400 nM. Immersing the polymethyl methacrylate with 50 μM psoriasin completely eradicates fungal growth. Psoriasin has low cytotoxicity in HeLa cells at a concentration higher than 12 μM and no toxic effect on human gingival fibroblasts.This study marks psoriasin as an effective alternative to conventional antifungal treatments for denture stomatitis and a safe alternative to chemical antifungals in dental medicine and beyond. [ABSTRACT FROM AUTHOR]

To evaluate the effect of antiseptic soap on single and dual-species biofilms of Candida albicans and Streptococcus mutans on denture base and reline resins. Samples of the resins were distributed into groups (n = 9) according to the prevention or disinfection protocols. In the prevention protocol, samples were immersed in the solutions (Lifebuoy, 0.5% sodium hypochlorite solution and PBS) for 7, 14 and 28 days before the single and dual-species biofilms formation. Overnight denture disinfection was simulated. In the disinfection protocol, samples were immersed in the same solutions during 8 hours after the single and dual-species biofilms formation. Antimicrobial activity was analyzed by counting colony-forming units (CFU/mL) and evaluating cell metabolism. Cell viability and protein components of the biofilm matrix were evaluated using confocal laser scanning microscopy (CLSM). Data were submitted to ANOVA, followed by Tukey's post-test (α = 0.05) or Dunnett's T3 multiple comparisons test. In the prevention protocol, Lifebuoy solution effectively reduced the number of CFU/mL of both species. In addition, the solution decreased the cell metabolism of the microorganisms. Regarding disinfection protocol, the Lifebuoy solution was able of reduce approximately of 2–3 logs for all the biofilms on the denture base and reline resin. Cellular metabolism was also reduced. The images obtained with CLSM corroborate these results. Lifebuoy solution was effective in reducing single and dual-species biofilms on denture base and reline resins. [ABSTRACT FROM AUTHOR]

In order to reduce the release of volatile organic compounds (VOCs), it is of great practical significance to develop water-based self-polishing antifouling coatings instead of traditional acrylic self-polishing antifouling coatings. However, when preparing film forming matrix resin emulsions for water-based antifouling coatings, the use of emulsifiers in large amounts causes filmforming defects and poor adhesion. Herein, soap-free emulsion polymerization is utilized to prepare resin emulsions by copolymerization of hydrophilic monomers, lipophilic monomers and polymerizable hydrophilic ionic monomers. The hydrophilic structure can give the water-based polymer selfemulsification function to maintain the stability of the emulsion and can promote the fusion between the latex particles by forming hydrogen bonds and coordination bonds, and its connection with the pigments and fillers in the coating can also promote the excellent film formation of the coating. The experimental results show that the water-based self-polishing antifouling resin emulsion has good storage stability and compatibility with the pigments and fillers. The coatings formulated using this emulsion as the film-forming matrix firmly adhered to substrates and displayed satisfactory antifouling performance even after being exposed to a real sea environment for 18 months. This study presents a simple approach for the development of water-based resin emulsion with good storage stability and good water-based self-polishing marine antifouling coatings. [ABSTRACT FROM AUTHOR]

There has been enormous research on diagnostic and therapeutic dental methods due to the growing recognition of oral wellness. Numerous studies in this area have resulted in dental biomaterials, including polymers, metals, and acrylic resins, essential to restore teeth affected by illnesses or accidents. Compared to other biomaterials, such as metals or polymers, ceramics offer distinct features. Materials like zirconia and alumina demonstrate their high intrinsic strength, making them appropriate for biomedical applications like dental implants or artificial joints. Additionally, they have outstanding biocompatibility, which lowers the possibility of adverse effects or inflammation. Some ceramics, like hydroxyapatite (HA) and bioactive glasses, even encourage tissue integration and regeneration. Moreover, because of their adaptability, they can be precisely shaped and composed to emphasize specific characteristics. Yttria‐stabilized tetragonal zirconia offers outstanding mechanical properties and biocompatibility but faces concerns over long‐term durability due to low‐temperature degradation. To address this, researchers have developed non‐oxidic ceramics like silicon nitride and advanced oxide‐based materials like alumina‐zirconia composites, aiming to enhance the durability and reliability of biomedical applications. In this review, we highlighted the recent advancements in ceramic dental implants; examples and applications of different ceramics‐based materials, including zirconia, alumina, HA, and beta calcium phosphate, are provided in detail. [ABSTRACT FROM AUTHOR]

The limited physical and mechanical properties of polymethyl methacrylate (PMMA), the current gold standard, necessitates exploring improved denture base materials. While three-dimensional (3D) printing offers accuracy, efficiency, and patient comfort advantages, achieving superior mechanics in 3D-printed denture resins remains challenging despite good biocompatibility and esthetics. This review investigates the potential of innovative materials to address the limitations of 3D-printed denture base materials. Thus, this article is organized to provide a comprehensive overview of recent efforts to enhance 3D-printed denture base materials, highlighting advancements. It critically examines the impact of incorporating various nanoparticles (zirconia, titania, etc.) on these materials' physical and mechanical properties. Additionally, it delves into recent strategies for nanofiller surface treatment and biocompatibility evaluation and explores potential future directions for polymeric composites in denture applications. The review finds that adding nanoparticles significantly improves performance compared to unmodified resins, and properties can be extensively enhanced through specific modifications, particularly silanized nanoparticles. Optimizing 3D-printed denture acrylics requires a multifaceted approach, with future research prioritizing novel nanomaterials and surface modification techniques for a novel generation of superior performance, esthetically pleasing, and long-lasting dentures. [ABSTRACT FROM AUTHOR]

The monomer structure, polymerization methods and application status of waterborne acrylic resin are briefly described. A systematic summary of the research progress in modifying waterborne acrylic resins based on different materials was provided, modified materials can be summarized as nanomaterials, organic silicon, organic fluorine, polyurethane and epoxy resin, as well as some new materials. This article focuses on the reaction mechanism, corresponding mierostructure, and performance improvement of water- borne acrylic resin modified with modified materials. The article looks forward to the development direction of water-based acrylic coatings. [ABSTRACT FROM AUTHOR]

BACKGROUND: For placement of intraradicular posts the intracanal filling material has to be removed. If drills are employed for this purpose, extra widening of the canal, incomplete cracks or root perforation are probable when inappropriate size of drill is used. OBJECTIVE: This in vitro study assessed the efficacy of radiographs taken after completion of root canal therapy in selecting the appropriate-sized Peeso reamer for post space preparation. METHODS: Canals of 53 extracted maxillary and mandibular teeth of different types were cleaned and shaped. Then with acrylic resin 3-dimensional model of the intracanal space of each tooth was fabricated. Next, all canals were filled with gutta-percha and teeth were radiographed buccolingually. Based on these radiographs two observers selected a Peeso reamer that best matched each canal's diameter. The diameter of the selected Peeso reamer was compared to the diameter of the corresponding resin model of each canal by two independent observers and the difference was measured. The data were analyzed by paired sample t -test using SPSS version 22. RESULTS: The diameter of the selected Peeso reamers ranged from 0.21 mm smaller to 0.12 mm larger than the diameter of intracanal spaces. The difference between reamer and resin model was less than 0.1 mm in 75% of the cases. CONCLUSION: The result of this study suggests that post-operation endodontic radiographs are reliable means for selecting a size of Peeso reamer that does not encroach on dentinal wall during removal of intracanal filling material and post space preparation. [ABSTRACT FROM AUTHOR]

High‐barrier performance, especially under extreme working conditions, is the key to replacing other types of packaging materials with paper‐based materials. In this paper, two biomass‐based polymers, sodium alginate (SA), and chitosan, were used to form a barrier coating with silicone emulsions to prepare a high‐performance paper‐based barrier material. By double coating, the water and oilproof functions were superimposed. The two prepared coated papers were characterized by infrared spectroscopy analysis, contact angle test, and scanning electron microscopy analysis, while their water resistance, oil resistance, thermal oil resistance, and thermal stability were tested. The water and oil repellency were achieved by double coating. The Cobb value of the chitosan‐silicone emulsion‐coated paper reached 5.3 g/m2, with a Kit grade of Level 12, and could block the penetration of castor oil at 80°C within 24 h. The Cobb value of the sodium alginate‐silicone emulsion‐coated paper was 41.6 g/m2, much higher than that of the uncoated paper, with a Kit grade of up to Level 10, which could slow down the rate of castor oil penetration at 80°C within 24 h. The test results showed that there was no chemical reaction between the paper‐based coatings, and the coated paper surface had good film formation, while the double coating method increased the thermal decomposition temperature of the overall barrier coating, effectively improving the thermal stability of the coating and achieving high‐barrier performance at lower cost and under extreme working conditions. Highlights: Water and oil resistance under extreme operating conditions.High‐performance paper‐based barrier materials.Dual‐layer coating method for water and oil repellency.High‐barrier performance at lower cost.Excellent hot oil resistance and thermal stability. [ABSTRACT FROM AUTHOR]

Introduction: Endocrown preparation of endodontically treated teeth as final restoration has been extensively studied for different teeth. Bindl et al. questioned the application of endocrowns for premolars due to the pulp chamber space's smaller dimensions, which diminish bonding surface area. The addition of ferrule into the endocrown preparations of premolars has not been extensively studied. Aims and Study Design: Comparative evaluation of incorporation of the ferrule in premolars endocrown designs to check any alterations in their fracture resistance. Materials and Methods: The sample consisted of 40 maxillary first premolars without cracks or caries, extracted for orthodontic or periodontal purposes. The teeth were individually mounted with cold-cure acrylic resin. Group A: Composite endocrown without ferrule and Group B: Composite endocrown with ferrule. An endocrown former was prepared with elastomeric polyvinyl siloxane material (GC Exaclear). Endocrowns were then prepared with dual-cure core build-up composite-Core-x flow (Dentsply Maillefer, Switzerland) using the endocrown former so that morphologically, they all were almost identical. Endocrowns are cemented by dual-cure resin cement following manufacturer instructions. The fracture resistance of endocrowns with and without ferrule was evaluated and compared. Results and Observations: The data were tabulated in Microsoft Excel and analyzed with SPSS version 24 software. The variables were presented with mean, standard deviation, and independent t-test. The P = 0.05 is considered statistically significant. Group B (with ferrule) showed higher fracture resistance (622.06 N) than Group A (537.59 N) (without ferrule). Independent t-test showed that the difference was statistically significant (P = 0.008). Conclusion: Comparing the failure load findings, it could be concluded that ferrule-containing endocrown needed greater loads than ordinary endocrown restorations for failure. [ABSTRACT FROM AUTHOR]