NaOCl Application after Acid Etching and Retention of Cervical Restorations: A 3-Year Randomized Clinical Trial.

This study evaluated the retention of composite resin restorations in noncarious cervical lesions (NCCLs) performed with or without pretreatment with 10% NaOCl solution (deproteinization). A randomized, controlled, split-mouth, double-blinded trial was carried out. Thirty patients with at least two NCCLs were included in the study. The NCCLs were randomly allocated into two treatment groups: control (acid etching with 37% phosphoric acid + placebo solution + Adper Single Bond 2/3M Oral Care + Filtek Z350/3M Oral Care) or experimental group (acid etching with 37% phosphoric acid + 10% NaOCl solution + Adper Single Bond 2 + Filtek Z350). A calibrated examiner evaluated the restorations at baseline (1 week) and recalls (6, 12, 24, and 36 months) using the FDI criteria. The primary outcome evaluated was retention of the restorations. Data were analyzed by the Kaplan-Meier method and the log-rank test (α=0.05). After 3 years, 64 restorations were evaluated in 23 patients. The annual failure rate was 9% for the control group and 17.8% for the experimental group (deproteinization technique). Considering the failures and their distribution among the characteristics of the patients and NCCLs, no statistically significant differences were observed for the control and experimental treatment groups (p=0.077) or the number of teeth in the mouth (p=0.320). Restorations in the mandible (p=0.039) and premolars (p=0.013) showed significantly lower clinical survival rates. The deproteinization pretreatment with a 10% NaOCl solution did not promote additional retention of restorations in NCCLs. (clinicaltrials. gov: NCT03086720).

Is Conventional Resin Cement Adhesive Performance to Dentin Better Than Self-adhesive? A Systematic Review and Meta-Analysis of Laboratory Studies.

CLINICAL RELEVANCE: Conventional multistep resin cements presented higher adhesive performance to dentin than simplified self-adhesive cements, which is an important criterion for indirect restoration prognosis. SUMMARY: This study aimed to conduct a systematic review of the literature on laboratory studies assessing bonding performance to dentin of conventional and self-adhesive resin cements, in cementing indirect restorations. This review was reported according to the PRISMA Statement. Of a total of 518 studies, 36 were screened full text and reviewed according to exclusion criteria. Nineteen papers were included in the systematic review and meta-analyses, according to the following inclusion criteria: studies that evaluated the bond strength to dentin of indirect restorations cemented with dual conventional or self-adhesive resin cements and those that presented bond strength data in MPa as an outcome. Statistical analyses were conducted using Rev-Man 5.1. Comparisons were performed with random effects models at 5% significance level. A global analysis comparing conventional and self-adhesive cements and three subgroup analyses comparing immediate and long-term results were performed. Global analysis showed a difference between groups, with conventional resin cements presenting higher bond strength results than self-adhesive resin cements, in immediate and long-term time periods (both p=0.03). Immediate and longterm bond strength results were different for self-adhesive cements, favoring immediate bond strength (p=0.03), but immediate and long-term bond strength results for conventional resin cements were not different (p=0.06). Medium or high risk of bias was found in all studies. Conventional multistep resin cements showed superior overall adhesive performance compared with simplified self-adhesive resin cements when used to cement indirect restorations to dentin.

Bovine tooth is a substitute for human tooth on bond strength studies: A systematic review and meta-analysis of in vitro studies.

OBJECTIVES: This study aimed to systematically review the literature to compare the bond strength values achieved from human and bovine teeth of in vitro studies. DATA AND SOURCE: The PubMed/MEDLINE, ISI Web of Science and Scopus electronic databases were searched to select laboratorial studies that evaluated adhesive systems bond strength to human and bovine teeth. No publication year or language restriction was considered. STUDY SELECTION: From 1,285 potentially eligible studies, 15 were selected for full-text analysis, 11 were included in the systematic review and 9 in the meta-analysis. Two authors independently selected the studies, extracted the data and assessed the risk of bias. Mean differences were obtained by comparing bond strength values between human and bovine teeth (overall analysis), and considering enamel and dentin separately (subgroups analysis). Statistical analysis was performed using RevMan5.1, with random effects model, at a significance level of p=0.05. RESULTS: No significant difference was found between human and bovine teeth (p=0.35), either for enamel (p=0.07) or for dentin (p=0.93) substrates. Low to moderate heterogeneity was found on the meta-analysis. All included studies in the systematic review scored between medium and high risk of bias. CONCLUSIONS: Bovine teeth can be a reliable substitute for human ones on bond strength studies of adhesive systems to both enamel and dentin substrates.

The effect of grinding on the mechanical behavior of Y-TZP ceramics: A systematic review and meta-analyses.

The aim of this study was to systematically review the literature to assess the effect of grinding on the mechanical properties, structural stability and superficial characteristics of Y-TZP ceramics. The MEDLINE via PubMed and Web of Science (ISI - Web of Knowledge) electronic databases were searched with included peer-reviewed publications in English language and with no publication year limit. From 342 potentially eligible studies, 73 were selected for full-text analysis, 30 were included in the systematic review with 20 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Statistical analyses were performed using RevMan 5.1, with random effects model, at a significance level of 0.05. A descriptive analysis considering phase transformation, Y-TZP grain size, Vickers hardness, residual stress and aging of all included studies were executed. Four outcomes were considered in the meta-analyses (factor: grinding x as-sintered) in global and subgroups analyses (grinding tool, grit-size and cooling) for flexural strength and roughness (Ra) data. A significant difference (p<0.05) was observed in the global analysis for strength, favoring as-sintered; subgroup analyses revealed that different parameters lead to different effects on strength. In the global analysis for roughness, a significant difference (p<0.05) was observed between conditions, favoring grinding; subgroup analyses revealed that different parameters also lead to different effects on roughness. High heterogeneity was found in some comparisons. Generally grinding promotes decrease in strength and increase in roughness of Y-TZP ceramics. However, the use of a grinding tool that allows greater accuracy of the movement (i.e. contra angle hand-pieces coupled to slowspeed turbines), small grit size (<50µm) and the use of plenty coolant seem to be the main factors to decrease the defect introduction and allow the occurrence of the toughening transformation mechanism, decreasing the risk of deleterious impact on Y-TZP mechanical properties.

Low-temperature degradation of Y-TZP ceramics: A systematic review and meta-analysis.

The aim of this study was to systematically review the literature to assess if low-temperature degradation (LTD) simulation in autoclave promotes deleterious impact on the mechanical properties and superficial characteristics of Y-TZP ceramics compared to the non-aged protocol. The MEDLINE via PubMed electronic database was searched with included peer-reviewed publications in English language and with no publication year limit. From 413 potentially eligible studies, 49 were selected for full-text analysis, 19 were included in the systematic review with 12 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Statistical analysis was performed using RevMan 5.1, with random effects model, at a significance level of p<0.05. Descriptive analysis of monoclinic phase content data showed that aging in autoclave promotes an increase in m-phase content (ranging from 0% up to 13.4% before and 2.13% up to 81.4% after aging) with intensity associated to the material susceptibility and to the aging parameters (time, pressure and temperature). Risk of bias analysis showed that only 1 study presented high risk, while the majority showed medium risk. Five meta-analyzes (factor: aging×control) were performed considering global and subgroups analyzes (pressure, time, temperature and m-phase % content) for flexural strength data. In the global analysis a significant difference (p<0.05) was observed between conditions, favoring non-aging group. Subgroup analysis revealed statistical difference (p<0.05) favoring non-aging, for aging time >20h. However, for shorter aging times (≤20h), there was no difference between groups. Pressure subgroup analysis presented a statistical difference (p<0.05) only when a pressure ≥2bar was employed, favoring non-aging group. Temperature subgroup analysis showed a statistical difference (p<0.05) only when temperature=134°C was used, favoring the non-aging group. M-phase % content analysis presented statistical difference (p<0.05) when more than 50% of m-phase content was observed, favoring non-aging group. High heterogeneity was found in some comparisons. Aging in autoclave promoted low-temperature degradation, impacting deleteriously on mechanical properties of Y-TZP ceramics. However, the effect of LTD depends on some methodological parameters indicating that aging time higher than 20h; pressure ≥2bar and temperature of 134°C are ideal parameters to promote LTD effects, and that those effect are only observed when more than 50% m-phase content is observed.

MMP Inhibitors on Dentin Stability: A Systematic Review and Meta-analysis.

The aim of this study was to systematically review the literature for in vitro and ex vivo studies that evaluated the effect of matrix metalloproteinase (MMP) inhibitors during the adhesive procedure on the immediate and long-term resin-dentin bond strength. The search was conducted in 6 databases with no publication year or language limits, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. From 1,336 potentially eligible studies, 48 were selected for full-text analysis, and 30 were included for review, with 17 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Pooled effect estimates were expressed as the weighted mean difference between groups. The most used MMP inhibitor was chlorhexidine (CHX). Immediate bond strength results showed no difference between 2% CHX and control; however, a difference was found between 0.2% CHX and control at baseline. After aging, CHX presented higher bond strength values compared to control groups (p < .05). However, this was not observed for longer periods of aging. High heterogeneity was found in some comparisons, especially for the water storage aging subgroup. Subgroup analyses showed that self-etching and etch-and-rinse adhesives are benefited by the CHX use. From the studies included, only 1 presented low risk of bias, while the others showed medium or high risk of bias. The use of MMP inhibitors did not affect the immediate bond strength overall, while it influenced the aged bond strength. Aging procedures influenced bond strength values of the dentin adhesion stability.

A multifunctional device to simulate oral ageing: the "Rub&Roll".

UNLABELLED: This article describes an in vitro fatigue and/or wear simulator enabling controlled application of force, speed, type of liquids and duration, to mimic challenges representative for the human oral environment. The device consists of a container in which a cylinder with specimen holder is placed which drives another cylinder (rod). The rod rotates in an opposite direction to the rotation of the stirring motor, rolling over the specimens mounted in the cylinder. When the rod contacts the specimen a force is applied to mimic processes in the oral environment. The design, working and construction principles of a new device, the Rub&Roll, and some of the possible applications are described Four different application examples are presented: occlusal wear in an low acidic abrasive slurry; combined erosive and abrasive wear of enamel exposed to apple juice or apple pulp; the wear of sealant material in natural teeth in an abrasive slurry; and the influence of mechanical loading cycles on micro tensile bond strength of an adhesive system to dentin Application of the "Rub & Roll" device showed results which are clinically relevant, reproducible and in accordance with existing literature. CONCLUSIONS: The Rub&Roll enables controlled application of chemical and mechanical loading, allowing variation of force, sliding distance, velocity, number of cycles, and frequency, and a combination with erosive and abrasive challenges representative of those in the oral environment.

Do educational methods affect students' ability to remove artificial carious dentine? A randomised controlled trial.

This trial aimed to evaluate the influence of two educational methods on students' ability to remove artificial carious dentine. Traditional lecture and lecture plus a live demonstration of artificial carious tissue removal were compared in a blind two-parallel-group design. Twenty-six students were randomly divided into two groups, and their skills were evaluated according to the following criteria: time spent on the dentine excavation procedure (in min), students' perceived confidence in conducting the procedure (graded assessed on a scale from 0 to 10), and the outcome of artificial carious tissue removal, evaluated by measuring the residual dyed artificial carious dentine layer (in µm). Statistical analyses were carried out using a t-test to compare the students' confidence and time spent on the procedure, and a two-way ANOVA was used to compare residual artificial decayed dentine with educational methods and tooth region (incisal, medium, and cervical thirds) as factors. There were no differences between the methods regarding excavation time (P = 0.898) and students' confidence (P = 0.382). The residual artificial carious dentine results showed that the educational method (P < 0.001) and cavity region (P < 0.001) were statistically significant, as was their interaction (P = 0.040). The lecture plus live demonstration group presented the best results for artificial caries removal. Although there were no differences between the two groups for the cervical region, the best results for the lecture plus live demonstration group was in the other two-thirds of the tooth.