Effect of ultra-fast high-intensity light-curing on the properties of a new bulk-fill restorative resin composite system: A Scoping Review.

Background: This scoping review aims to analyze the impact of rapid high-intensity light-curing on a new bulk-fill resin-based composites (RBCs) designed for this type of polymerization. Material and Methods: This scoping review was reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and Joanna Briggs Institute Manual of Evidence Synthesis. The methods were registered on the Open Science Framework (). The literature search was conducted in PubMed/MEDLINE, Embase, Web of Science, Scopus and Cochrane Library databases. Eligibility was considered for in vitro and clinical studies evaluating the effects of ultra-fast high-intensity light-curing on a new system of bulk-fill RBCs. Results: Of 1.688 articles identified, 27 were included in the qualitative synthesis. All studies were conducted in vitro. A total of 2.432 specimens were evaluated. The studies have shown that shortness light-curing may result in similar properties (stress generated by polymerization shrinkage, marginal integrity, and bond strength to dental interface) for the new bulk-fill RBCs. Conclusions: Therefore, the new bulk-fill RBCs can be light-cured with a short exposure time and high intensity, providing a time-saving benefit in clinical practice, with similar results to standard light-curing in conventional composites, although, its use should be approached with caution in the flowable composite. Key words:Resin composites, polymerization, dental materials, review.

Assessment of Surface Roughness, Color, and Bonding Efficacy: Self-Adhesive vs. Conventional Flowable Resin.

This in vitro study aimed to analyze the surface roughness (Ra) and color stability (ΔEab, ΔE00) following simulated mechanical brushing and to evaluate the microtensile (µTBS) of self-adhering resin flowable (SARF) to dentin. The selected materials were Constic, Yflow AS, and Tetric N flow (TNF/control). Thirty composite resin cylinders were fabricated for surface property evaluation. Ra and color were assessed both before and after simulated brushing. The thresholds of 50:50% perceptibility and acceptability of color differences in the evaluated resins were assessed. For µTBS analysis, fifteen molars were selected, sectioned to expose flat dentin surfaces, and restored according to the manufacturers' instructions for microtensile testing. There were statistically significant differences in Ra among the groups, with Constic exhibiting the highest Ra value (0.702 µm; p < 0.05), whereas Yflow AS presented the lowest Ra value (0.184 µm). No statistically significant difference in color was observed among the groups (p > 0.05). The 50:50% perceptibility and acceptability thresholds were set at 1.2 and 2.7 for ΔEab and 0.8 and 1.8 for ΔE 00. All the results fell within the acceptable limits. The mean µTBS values of Constic, Yflow AS, and TNF were 10.649 MPa, 8.170 MPa, and 33.669 MPa, respectively. This study revealed increased Ra and comparable color stability among all the tested composite resins after abrasion. However, the SARF exhibited lower µTBS compared to conventional using an adhesive system.

Color Stability of Single-Shade Resin Composites in Direct Restorations: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The objective was to compare the color match and color stability behavior of single- and multi-shade resin-based composites (RBCs) used for direct restorations. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized clinical trials evaluating the shade performance of single-shade RBCs in direct restorations were included. A search of the scientific literature was performed in five databases (April 2024). The meta-analysis was performed using RevMan 5.4, calculating the risk difference (RD) and 95% confidence interval (CI) of the dichotomous outcome using a random effects model. Bias was assessed using the RoB 2.0 tool, and certainty of evidence was assessed using the GRADEpro tool. Four studies were selected, with 263 restorations analyzed. The results showed comparable performance between single-shade RBCs and multi-shade RBCs in terms of color match and color stability over 12 months. Three studies had a low risk of bias with all expected results, and one study had some concerns. The certainty of evidence for color stability was considered low for all follow-up periods due to the small number of events and sample size. According to the United States Public Health Service Evaluation (USPHS) and the World Dental Federation (FDI), there is comparable clinical color performance between single-shade and multi-shade RBCs over 12 months.

Effect of Rapid High-Intensity Light-Curing on Increasing Transdentinal Temperature and Cell Viability: An In Vitro Study.

BACKGROUND: This study investigated effects of rapid high-intensity light-curing (3 s) on increasing transdentinal temperature and cell viability. METHODS: A total of 40 dentin discs (0.5 mm) obtained from human molars were prepared, included in artificial pulp chambers (4.5 × 5 mm), and subjected to four light-curing protocols (n = 5), with a Valo Grand light curing unit: (i) 10 s protocol with a moderate intensity of 1000 mW/cm2 (Valo-10 s); (ii) 3 s protocol with a high intensity of 3200 mW/cm2 (Valo-3 s); (iii) adhesive system + Filtek Bulk-Fill Flow bulk-fill composite resin in 10 s (FBF-10 s); (iv) adhesive system + Tetric PowerFlow bulk-fill composite resin in 3 s (TPF-3 s). Transdentinal temperature changes were recorded with a type K thermocouple. Cell viability was assessed using the MTT assay. Data were analyzed using one-way ANOVA and Tukey tests for comparison between experimental groups (p < 0.05). RESULTS: The 3 s high-intensity light-curing protocol generated a higher temperature than the 10 s moderate-intensity standard (p < 0.001). The Valo-10 s and Valo-3 s groups demonstrated greater cell viability than the FBF-10s and TPF-3 s groups and statistical differences were observed between the Valo-3 s and FBF-10 s groups (p = 0.023) and Valo-3 s and TPF-3 s (p = 0.025), with a potential cytotoxic effect for the FBF-10 s and TPF-3 s groups. CONCLUSIONS: The 3 s rapid high-intensity light-curing protocol of bulk-fill composite resins caused a temperature increase greater than 10 s and showed cell viability similar to and comparable to the standard protocol.

Impact of using magnifying dental loupes on clinical performance during tooth preparation: A systematic review.

Background: To assess whether using magnification loupes affects tooth preparation working posture performed by undergraduate students and dentistry professionals and whether it influences the quality of the preparation, operator satisfaction and procedure time. Material and Methods: This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and registered in the International Prospective Register of Systematic Review (CRD42023482377). Electronic searches were conducted in PubMed/Medline, Cochrane Library, Web of Science, and Scopus databases for relevant articles published up to August 2023. Clinical or laboratory studies evaluating cavities or dental preparations performed with and without magnification loupes were considered eligible. The outcomes were operator working posture, dental preparation quality, operator satisfaction, and procedure time. The quality of the studies was evaluated using the JBI Critical Appraisal tools for Quasi-Experimental Studies. Results: The searches retrieved 1493 articles. Based on the eligibility criteria, 11 laboratory studies were included, where 410 undergraduate and graduate dental students conducted dental preparations in 1851 dental specimens. Of the 11 selected studies, 6 evaluated the working posture, 6 assessed the quality of the dental preparations, 5 reported operator satisfaction, and 2 assessed procedure time. The results showed that magnifying loupes significantly improved operator working posture, but did not influence the quality of tooth preparations. Although satisfaction reports about experiences with magnifying loupes were favorable, no significant difference was found. Conclusions: Magnification loupes improved operator working posture. However, clinical studies with more scientific evidence are needed for steady conclusions regarding operator satisfaction and procedural time. Key words:Magnification, dental loupes, tooth preparation, cavity preparation, dental education.

Color and surface roughness alterations of bulk-fill resin composites submitted to simulated toothbrushing with whitening dentifrices

Aim: To evaluate the surface roughness and color stability of bulk-fill resin composites after simulated toothbrushing with whitening dentifrices. The radioactive/relative dentin abrasion (RDA) and radioactive/relative enamel abrasion (REA) of dentifrices were also assessed. Methods: Specimens (n=10) of Tetric N Ceram Bulk Fill (TNCB), Filtek One Bulk Fill (FOB) resin composites, and Z100(Control) were prepared using a cylindrical Teflon matrix. Surface roughness (Ra, µm) was assessed by a roughness meter and the color evaluations (ΔEab , ΔE00 , WID ) were performed using a digital spectrophotometer based on the CIELAB system. Three measurements were performed per sample, before and after simulated toothbrushing with 3D Oral-B White Perfection (3DW) and Black is White (BW) dentifrices. The abrasivity (REA and RDA values) of the used dentifrices was also determined by the Hefferren abrasivity test. Results: The Ra values increased significantly in all resin composites after 3DW and BW toothbrushing. The acceptable threshold color varied among resin composites, and TNCB and Z100 presented the highest ΔEab and ΔE00 for BW dentifrice. The 3DW dentifrice was significantly more abrasive than BW dentifrice on enamel and dentin. Conclusions: simulated toothbrushing with tested whitening dentifrices increased the surface roughness at acceptable levels. The Tetric N Ceram Bulk-fill and Z100 composite showed the highest color alteration in BW. 3D White Perfection dentifrice was more abrasive on dentin and enamel than Black is White.

Evaluation of Single-Shade Composite Resin Color Matching on Extracted Human Teeth.

Introduction: Universal single-shade composite resins are characterized by a property that enables the creation of restorations that mimic tooth structure to the extent possible with fewer shades of color. Objectives: This study aimed to instrumentally and visually evaluate the color correspondence of two single-shade composite resins in extracted human teeth multishade composite resins. Methods: Upper central incisors and upper and/or lower molars with intact buccal surfaces were selected. The study consisted of a control group (n = 20): Z250 XT (3M ESPE) (G1) multishade composite resin in colors A1 to A4, and a test group (n = 20) divided further into two equal groups, consisting of single-shade composite resin Omnichroma (Tokuyama Dental) (G2) and single-shade composite resin Vittra APS Unique from (FGM) (G3). Instrumental evaluation was performed using a spectrophotometer, and visual evaluation was performed by three observers. Descriptive measurements related to the differences in color obtained through instrumental means were analyzed using mean and standard deviation, wherein the means were compared using ANOVA, applying the Bonferroni post hoc test. Results: A statistically significant difference was observed among the groups (G1, G2, and G3) (ANOVA: p < 0.001). For the visual assessment, regardless of the assessment group, 77.49% of the teeth were within the acceptable color-match classification, with the single-shade resins showing better correspondence than the multishade resins. Conclusion: Single-shade composite resins showed different color-matching results when compared to multishade resins, both in spectrophotometry and visual evaluations. Clinical Significance. Single-shade composite resins simplify the shade-selection process and are promising materials for use in dental practice.

Postoperative sensitivity in posterior resin composite restorations with prior application of a glutaraldehyde-based desensitizing solution: A randomized clinical trial.

OBJECTIVES: To evaluate the effect of a glutaraldehyde-based desensitizer on the postoperative sensitivity (POS) in posterior resin composite restorations up to 12 months using a universal adhesive (Tetric N-Bond Universal) with selective enamel etching (SE) or an etch-and-rinse (ER) strategy. METHODS: Class I and class II resin composite restorations (n = 220) at least 3 mm deep were inserted in 55 subjects. The universal adhesive was applied using the SE (self-etch strategy on dentin with selective enamel etching) or the ER strategy, with or without prior application of a glutaraldehyde-based desensitizer (Gluma Desensitizer - GL) to form groups SEGL and ERGL. A bulk-fill resin composite (Tetric NCeram Bulk Fill) was used for all restorations. Spontaneous POS was assessed 7 days after the restorative procedure using the Visual Analog Scale (VAS) and the Numeric Rating Scale (NRS). After 7, 14, and 30 days of completing each restoration, the subjects were reassessed to evaluate POS caused by stimulation with an air blast, horizontal and vertical percussion. In addition, marginal discoloration, marginal adaptation, fracture, and recurrence of caries were evaluated using the FDI (World Dental Federation) criteria after 7 days and at 12 months. RESULTS: No significant spontaneous or stimuli-induced POS was observed when restorations with or without GL were compared (p>0.05). A higher risk of spontaneous POS was observed within 7 days (40.0%; 95% CI 28.1 to 53.1), without statistically significant differences among groups. None of the participants reported POS at 12 months, however five restorations were considered clinically unsatisfactory (p > 0.05). CONCLUSIONS: The previous application of GL did not significantly reduce spontaneous or stimuli-induced POS in posterior resin composite restorations at any time, regardless of the adhesive strategy used. CLINICAL SIGNIFICANCE: The use of a glutaraldehyde-based desensitizing agent did not generate lower incidence of postoperative sensitivity in resin composite posterior restorations.

Thirty-six-month clinical evaluation of posterior high-viscosity bulk-fill resin composite restorations in a high caries incidence population: interim results of a randomized clinical trial.

OBJECTIVES: This study compared the clinical performance of two bulk-fill (BF) and one conventional resin composite in a population with a high caries incidence. MATERIALS AND METHODS: A total of 138 class I and II restorations were performed and randomly divided into three groups (n = 46) with equal allocation: Filtek BF (FBF; 3M ESPE), Tetric EvoCeram BF (TBF; Ivoclar Vivadent), and control Filtek Z250 (Z250; 3M ESPE). The evaluations were performed using the USPHS and FDI criteria at baseline and after 12 and 36 months by a previously calibrated evaluator. The Friedman and Wilcoxon tests for paired data were used for statistical analysis (α = 0.05). RESULTS: The DMFT index at baseline was 9.44, with 87% from the decayed component. After 36 months, 108 restorations (n = 36) were evaluated. Two failures were observed for TBF at marginal adaptation and recurrence of caries, resulting in a survival rate of 94.44% and an annual failure rate (AFR) of 1.26%. No equivalence was observed between the criteria for surface roughness, marginal adaptation, and discoloration. CONCLUSIONS: The 36-month clinical performance of high-viscosity BF resin composites was comparable to conventional incremental-filled resin composites. The FDI criteria better presented the restorations' clinical success. However, in the case of failure, both criteria provided the same result. CLINICAL RELEVANCE: High-viscosity bulk-fill resin composites showed excellent performance after 36 months in a high caries incidence population. It can be considered a simplified alternative restoration method that reduces operating time and minimizes possible operator errors.

Clinical Performance of Bulk-Fill Resin Composite Restorations Using the United States Public Health Service and Federation Dentaire Internationale Criteria: A 12-Month Randomized Clinical Trial.

OBJECTIVE: This study was aimed to compare the 12-month clinical performance of two full-body bulk-fill resin composites Filtek bulk fill/3M ESPE (FBF) and Tetric EvoCeram bulk fill/Ivoclar Vivadent (TBF) and a conventional microhybrid resin composite Filtek Z250/3M ESPE (Z250) using the modified the United States Public Health Service (USPHS) and Federation Dentaire Internationale (FDI) criteria. Also, the agreement between the two evaluation criteria was evaluated at baseline and after 12 months of follow-up. MATERIALS AND METHODS: A total of 138 class I and II restorations were placed in posterior teeth (split-mouth design) of 46 volunteers following manufacturer's instructions and bonded with a self-etching bonding agent (Clear fill SE Bond/Kuraray). The restorations were evaluated at baseline and after 12 months of follow-up by three previously calibrated dentists (Cohen's K = 0.84). STATISTICAL ANALYSIS: Fisher's exact test and Pearson's Chi-squared test were used to evaluating the homogeneity of distribution of the clinical characteristics. Friedman's test was applied to evaluate differences among the resin composites. The results obtained for the USPHS and FDI criteria at the different observation times were compared using the Wilcoxon test. A level of significance of 0.05 was adopted for all tests. RESULTS: After 12 months (recall rate, 78.3%, n = 36 patients), the overall success rate was 99.07% for both criteria. Only one failed restoration (0.93%) was detected for each system during follow-up in the TBF group. CONCLUSION: The bulk-fill resin composites showed satisfactory clinical performance compared with conventional resin composite after 12 months. The percentage of the acceptable scores was significantly higher for the USPHS criteria, due to discrepancies in the score description for each criterion.

Microtensile Bond Strength of Bulk-fill Resin Composite Restorations in High C-factor Cavities.

AIM: To evaluate the microtensile bond strength (µTBS) and the fracture modes of four bulk-fill resin composites (Tetric EvoCeram Bulk Fill/Ivoclar Vivadent, Filtek Bulk Fill/3M ESPE, Venus Bulk Fill/Heraus Kulzer, and Filtek Bulk Fill Flow/3M ESPE) and one conventional incrementally filled resin composite (Filtek Z250/3M ESPE) inserted in class I cavities, after 24 hours and 6 months of water storage. MATERIALS AND METHODS: In all, 30 sound human extracted molars were divided into five restorative groups. Standardized class I cavities were prepared and restored following the manufacturer's instructions. The restored teeth were then assigned into one of the storage times (24 hours or 6 months). The molars were then cut into 1 mm2 sticks and submitted to µTBS. All fractured specimens were analyzed under a stereomicroscope (40×). Data were submitted to analysis of variance (ANOVA) and the Tukey post hoc test was applied for comparison between groups; and paired t test for comparison within storage times (p = 0.05). RESULTS: After 24 hours of storage, statistically significant differences were observed between Filtek Z250 and Filtek Bulk Fill Flow groups. However, after 6 months, no statistical differences were observed between groups. Additionally, no differences were observed for the µTBS between the storage times. Adhesive failures were the most frequent fracture mode after 24 hours (54%) and 6 months (43%), the resin cohesive fracture mode showed 16% for 24 hours and 14% for 6 months, the dentin cohesive fracture mode showed 14% for 24 hours and 26% for 6 months, and the mixed fracture mode showed 16% for 24 hours and 17% for 6 months. CONCLUSION: Bulk-fill resin composites obtained similar µTBS in high C-factor cavities as conventional incrementally filled resin composites. No bond strength reduction was observed after 6 months of storage. CLINICAL SIGNIFICANCE: Single increment restorations in high C-factor cavities with bulk-fill resin composites did not reduce µTBS after 24 hours or 6 months of storage. The comparable results to the conventional incrementally filled resin composites and the reduction in the operative time, make the bulk-fill resin composites a restorative option for posterior teeth restorations.

Complications with PMMA compared with other materials used in cranioplasty: a systematic review and meta-analysis.

Polymethyl methacrylate (PMMA) has been considered a suitable material for cranioplasty. However, no consensus has been reached concerning the best material for cranioplasty with regard to minimizing complications. Thus, this systematic review and meta-analysis aimed to compare the complication rates of PMMA with those of autologous bone and titanium mesh. This review was registered with PROSPERO (CRD42016042725). Systematic searches were conducted on PubMed/MEDLINE, Scopus, and Web of Science. The focus question was, "Do PMMA prostheses used in cranioplasty have complications rates similar to those of autologous bone and titanium mesh?" A meta-analysis of complication rates was performed on the basis of dichotomous outcomes assessed by risk ratio (RR) with corresponding 95% confidence intervals (CI). From 1014 data sources, 11 articles were selected according to eligibility criteria. These articles involved 1,256 individuals and 1,278 cranioplasties using autologous bone (n = 408), PMMA (n = 379), or titanium (n = 151). The follow-up period ranged from 63 days to 54.3 months. No difference was observed between the complication rates of PMMA and autologous bone (p = 0.94; RR, 0.98; 95%CI, 0.54-1.75) or between PMMA and titanium (p = 0.38; RR, 1.59; 95%CI, 0.57-4.48). Sub-analysis of the reasons for craniotomy (trauma/non-trauma) was conducted, which revealed no significant difference (p = 0.91; RR, 0.95; 95%CI, 0.37-2.42). The meta-analysis indicated that the use of PMMA yields complication rates that are near those of autologous bone and titanium mesh.

Complications with PMMA compared with other materials used in cranioplasty: a systematic review and meta-analysis

Abstract Polymethyl methacrylate (PMMA) has been considered a suitable material for cranioplasty. However, no consensus has been reached concerning the best material for cranioplasty with regard to minimizing complications. Thus, this systematic review and meta-analysis aimed to compare the complication rates of PMMA with those of autologous bone and titanium mesh. This review was registered with PROSPERO (CRD42016042725). Systematic searches were conducted on PubMed/MEDLINE, Scopus, and Web of Science. The focus question was, "Do PMMA prostheses used in cranioplasty have complications rates similar to those of autologous bone and titanium mesh?" A meta-analysis of complication rates was performed on the basis of dichotomous outcomes assessed by risk ratio (RR) with corresponding 95% confidence intervals (CI). From 1014 data sources, 11 articles were selected according to eligibility criteria. These articles involved 1,256 individuals and 1,278 cranioplasties using autologous bone (n = 408), PMMA (n = 379), or titanium (n = 151). The follow-up period ranged from 63 days to 54.3 months. No difference was observed between the complication rates of PMMA and autologous bone (p = 0.94; RR, 0.98; 95%CI, 0.54-1.75) or between PMMA and titanium (p = 0.38; RR, 1.59; 95%CI, 0.57-4.48). Sub-analysis of the reasons for craniotomy (trauma/non-trauma) was conducted, which revealed no significant difference (p = 0.91; RR, 0.95; 95%CI, 0.37-2.42). The meta-analysis indicated that the use of PMMA yields complication rates that are near those of autologous bone and titanium mesh.

Effect of dentin pretreatment with potassium oxalate: A 6-year follow-up.

Oxalate-based products are effective against dentine sensitivity and have been studied as an option to improve long-term adhesive bonding strength. Our aim was to evaluate the effect of potassium oxalate on the microtensile bond strength (µTBS) of the dentin/resin interface after 24 h, 1, and 6 years. Dentin on the occlusal surface of 16 human premolars was exposed and etched with 35% phosphoric acid. The teeth were divided into four groups. Two groups received 3% monohydrated potassium oxalate and the following adhesive systems and composites: Adper Scotchbond Multipurpose + FiltekZ350 (3M/ESPE) and Prime & Bond NT + Esthet-X (Dentsply). Two control groups did not receive potassium oxalate. Teeth were cut into sticks and kept in distilled water at 37°C for 24 h, 1, and 6 years. The sticks underwent µTBS testing after storage. ANOVA, Tukey's post hoc test, and paired t test were used to compare storage times (α = 0.05). The fracture mode of the specimens was classified under a stereomicroscope (40×). Morphology of the hybrid layer and the fracture pattern were observed with scanning electronic microscopy (SEM). Mean µTBS was high at 24 h and decreased after 1 and 6 years. After 6 years, the mean µTBS values were similar with no statistically significant difference between the groups (p = .121). SEM images showed proper dentin hybridization. Dentin pretreatment with potassium oxalate did not affect hybrid layer formation, but bond strength decreased over time after 24 h. Therefore, the clinical use of potassium oxalate to increase dentin bond durability is not indicated.

Pre-treating dentin with chlorhexadine and CPP-ACP: self-etching and universal adhesive systems.

Objective: The aim of the present study was to compare the effect of pre-treating dentin with chlorhexidine, at concentrations of 0.2% and 2%, and remineralizing paste containing CPP-ACP (MI Paste - GC) on the bond strength of adhesive systems. Material and methods: In total, 80 slides of dentin were used. These slides were 2 mm thick and were obtained from bovine incisors. Standard cavities were created using diamond bur number 3131. In the control groups, a Scotchbond Universal Adhesive (SUA) self-etching adhesive system of 3M ESPE and a Clearfil SE Bond (CSE) adhesive system of Kuraray were applied, following the manufacturer's instructions. In the other groups, dentin was pretreated with chlorhexidine (0.2% and 2%) for 1 min and with MI Paste for 3 min. The cavities were restored with Z350 XT resin (3M ESPE). After 24 h of storage, the push-out test was applied at a speed of 0.5 mm/min. Results: The different dentin pretreatment techniques did not affect the intra-adhesive bond strength. There was a difference between treatment with MI Paste and chlorhexidine 0.2% in favor of the SUA, with values of 15.22 and 20.25 Mpa, respectively. Conclusions: The different pretreatment methods did not alter the immediate bond strength to dentin. Differences were only recorded when comparing the adhesives.

Impact of toothbrushing with a dentifrice containing calcium peroxide on enamel color and roughness.

This in vitro study sought to evaluate both the bleaching potential and changes to average surface roughness (Ra) of enamel after brushing with a dentifrice. Fifty-four enamel specimens (4 x 4 x 2 mm) were divided into 3 groups (n = 18) and treated with 1 of 3 dentifrices: 1 with calcium peroxide, and 2 without. The samples were submitted to 20,000 brushing cycles. Color and Ra were measured before and after brushing. Although the Ra increased in all groups after brushing, only the dentifrice containing calcium peroxide resulted in an increase in reflectance.

Bond strength to dentin of total-etch and self-etch adhesive systems / Resistência de união à dentina de sistemas adesivos convencionais e autocondicionante

OBJECTIVE: To assess the bond strength to dentin of the Single Bond (3M ESPE) and XP Bond (Dentsply) total-etch and Adper SE Plus (3M ESPE) self-etch adhesive systems. METHODS: Fifteen healthy human third molars were randomly allocated across three different groups of five teeth each according to the adhesive system. The occlusal portion of each tooth was removed under refrigeration using a flexible diamond disc (EXTEC, Enfield, CT, USA) down to an area of dentin that did not reveal enamel, as confirmed under a 40X stereo microscope (Ramsor, São Paulo, Brazil). A standardized smear layer was created with #600 grit silicon-carbide paper. The adhesive systems were applied as per manufacturer recommendations, with the exception of the Adper SE Plus system, which was triple-polymerized. Composite resin blocks (5 mm) were placed on the dentin surface. The specimens were stored in distilled water for 24 hours at 37ºC. Using a flexible diamond disc (EXTEC, Enfield, CT, USA), toothpick-like specimens with an adhesive area of less than 1 mm² were obtained. A microtensile bond test was then carried out using a universal testing machine (KRATOS) with a crosshead speed of 0.5 mm/min. Analysis of variance (ANOVA) and Tukey's test were used for comparisons. RESULTS: The bond strength values obtained with each adhesive system were as follows: XP Bond, 96.24 MPa; Adper Single Bond, 72.39 MPa; Adper SE Plus, 49.91 MPa. CONCLUSION: In terms of bond strength to dentin, conventional adhesives outperform self-etching systems. .

OBJETIVO: Avaliar o grau de resistência de união à dentina dos sistemas adesivos de condicionamento ácido total Adper Single Bond (3M ESPE) e XP Bond (Dentsply) e autocondicionante Adper SE Plus (3M ESPE). MÉTODOS: Quinze terceiros molares humanos hígidos foram utilizados, divididos aleatoriamente em três grupos de cinco dentes cada, conforme o adesivo que seria utilizado. A porção oclusal foi removida com o auxílio de um disco flexível diamantado sob refrigeração, até expor uma área de dentina que não apresentasse ilhas de esmalte, comprovado em lupa esterioscópica em aumento de 40X. A smear layer foi padronizada em lixa d'água n°600. Na sequência os sistemas adesivos foram aplicados conforme as recomendações do fabricante, exceto o Adper SE Plus que teve seu tempo de polimerização triplicado. Sobre os dentes preparados foram construídos blocos de resina composta com 5mm de altura. As amostras foram armazenadas por 24 horas a 37°C em água destilada. Utilizando o disco flexível diamantado, foram obtidos corpos de prova com formato de palitos com área adesiva menor que 1mm². Em seguida o teste de microtração foi realizado numa Máquina de Ensaios Universal numa velocidade de 0,5 mm/min. Foram utilizados o teste ANOVA e comparações pareadas de Tukey. RESULTADOS: Os valores da resistência de união para cada sistema adesivo em Mpa foram: 96,24 (XP Bond); 72,39 (Adper Single Bond) e 49,91 (Adper SE Plus). CONCLUSÃO: Dessa forma, em relação à resistência de união à dentina, os adesivos convencionais apresentaram desempenho superior ao autocondicionante. .

Effect of polyacrylic acid on the interface and bond strength of self-adhesive resin cements to dentin.

PURPOSE: To examine the influence of 11.5% polyacrylic acid pretreatment on the interface and bond strength of self-adhesive resin cements (Maxcem Elite, RelyX Unicem, SeT) to dentin. MATERIALS AND METHODS: Fifty-six third molars were randomly divided into seven groups: RelyX ARC as control (ARC), RelyX Unicem (RLXU), Maxcem Elite (MCE), SeT (ST), polyacrylic acid+RelyX Unicem (RLXU-P), polyacrylic acid+Maxcem Elite (MCE-P), and polyacrylic acid+SeT (ST-P). Resin composite blocks were luted to flat dentin. After storage in distilled water for 24 h, sticks with a cross-sectional area of ca 0.80 mm2 were obtained (n = 24 per group) and submitted to a microtensile bond strength (µTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min. Two sets from each group were sectioned mesiodistally in the center of the crown and observed with a scanning electron microscope at 4000X magnification. RESULTS: The mean results of the µTBS test (MPa) followed by the same letter do not differ statistically significantly according to ANOVA and Tukey's post-hoc test (p < 0.05): ARC = 24.19 (± 6.90)a, RLXU-P = 23.12 (± 6.18)a, MCE-P = 13.09 (± 5.87)b, RLXU = 10.23 (± 2.88)b,c, and MCE = 8.14 (± 4.63)c. All SeT specimens failed during the cutting procedure. The hybrid layer was not observed for the self-adhesive resin cements, and resin tags were observed for RelyX Unicem and Maxem Elite when dentin was pretreated with polyacrylic acid. CONCLUSION: Pretreatment with 11.5% polyacrylic acid was effective for bonding RelyX Unicem and Maxcem Elite to dentin.

Filler morphology of resin-based low-viscosity materials and surface properties after several photoactivation times.

AIM: This study aimed to characterize the morphology of filler particles and to analyze the effect of shortened and extended photoactivation times on hardness (VHN) and cross-link density (CLD) of resin-based low-viscosity materials. METHODS: Sixteen commercially available materials were tested: four fissure sealants (Alpha Seal, Fluroshield Yellowed, Bioseal and Fluroshield White) and 12 flowable composites (Opallis T, Permaflo T, Opallis A2, Natural Flow A2, Master Flow A2, Permaflo A2, Filtek Z350 A2, Natural Flow O, Master Flow OA2, Opallis OA3.5, Filtek Z350 OA3, Opallis OP) at six curing times (10 s, 20 s, 30 s, 40 s, 50 s and 60 s). Specimens were fabricated (n = 5), analyzed by Scanning Electron Microscopy, by VHN and by CLD. RESULTS: Unimodal and multimodal filler particles sizes with spherical and irregular shapes were observed. Unfilled materials were also detected. There were no differences among curing times for either VHN or CLD. Opallis A2 and Opallis OA3.5 showed the highest VHN at all curing times, whereas Master Flow A2 and Master Flow OA2 presented the lowest VHN. Opallis A2 presented the highest CLD at all curing times and Alpha Seal showed the lowest CLD. CONCLUSIONS: Filler particle morphology differed among the resin-based low-viscosity materials tested. The shortest photoactivation time tested could yield similar VHN and CLD means to those provided by the most extended photoactivation time.