Influence of daily usage times on patients' compliance during at-home bleaching: a randomized clinical trial.

The effectiveness of at-home dental bleaching treatments depends on the time that bleaching products are in contact with the teeth surface and, consequently, on the adequate use of associated custom acetate trays. OBJECTIVE: This randomized single-blinded trial aimed to analyze if the daily usage time of these products influences the patient's compliance behavior when submitted to monitored at-home dental bleaching. Secondary outcomes were color change and tooth sensitivity. METHODOLOGY: Sixty-six volunteers were randomly distributed into three groups (n=22): patients were instructed to use the trays for 2 (G2), 4 (G4), and 8 (G8) hours daily. The daily dental bleaching compliance behavior was measured using a microsensor inserted into the trays. Subjective and objective color evaluation assessments were adopted at baseline (T0), one (T1), two (T2), and three weeks (T3) after the beginning of the bleaching treatment, as well as two weeks after the treatment (T4). Tooth sensitivity was analyzed using the VAS scale, ranging from T1 to T4. RESULTS: G2 showed a greater degree of cooperation than G8 and cooperation was inversely proportional to the recommended usage time. Significantly higher color change was observed in the upper arch for G8 when compared to G2 in subjective analysis, from T1 to T4. There were no statistical differences between the groups in objective analysis. CONCLUSION: Shorter recommended usage time of the bleaching product may improve the patient's compliance with at-home dental bleaching treatments. However, increased daily usage time may promote better subjective color change. Bleaching sensitivity was more significant in the first week for a longer time of use.

An 8-year follow-up of resin infiltration on anterior white spot lesions.

White spot lesions (WSLs) are sites of enamel surface and subsurface demineralization that increases tissue porosity and affects the teeth appearance. The resin infiltration technique proved to be a valid alternative to arrest caries lesion progression and to masking a color change in noncavitated WSLs. Thus, this study aims to report a clinical case of anterior WSLs treated with resin infiltration technique with an 8-year follow-up. The resin infiltration protocol was performed in an 18-year-old female patient presenting WSLs on the maxillary right lateral incisor, left central incisor, and left canine. The protocol followed the manufacturer's recommendations. The patient reported satisfaction with the smile appearance, at the end of the appointment. Infiltrated areas remained unchanged after an 8-year follow-up, showing an acceptable result for the patient's esthetic desires. After 8 years of evaluation, the resin infiltration technique proved to be a resistant and reliable alternative in preventing caries progression and in color masking WSLs.

Influence of daily usage times on patients' compliance during at-home bleaching: a randomized clinical trial

Abstract The effectiveness of at-home dental bleaching treatments depends on the time that bleaching products are in contact with the teeth surface and, consequently, on the adequate use of associated custom acetate trays. Objective This randomized single-blinded trial aimed to analyze if the daily usage time of these products influences the patient's compliance behavior when submitted to monitored at-home dental bleaching. Secondary outcomes were color change and tooth sensitivity. Methodology Sixty-six volunteers were randomly distributed into three groups (n=22): patients were instructed to use the trays for 2 (G2), 4 (G4), and 8 (G8) hours daily. The daily dental bleaching compliance behavior was measured using a microsensor inserted into the trays. Subjective and objective color evaluation assessments were adopted at baseline (T0), one (T1), two (T2), and three weeks (T3) after the beginning of the bleaching treatment, as well as two weeks after the treatment (T4). Tooth sensitivity was analyzed using the VAS scale, ranging from T1 to T4. Results G2 showed a greater degree of cooperation than G8 and cooperation was inversely proportional to the recommended usage time. Significantly higher color change was observed in the upper arch for G8 when compared to G2 in subjective analysis, from T1 to T4. There were no statistical differences between the groups in objective analysis. Conclusion Shorter recommended usage time of the bleaching product may improve the patient's compliance with at-home dental bleaching treatments. However, increased daily usage time may promote better subjective color change. Bleaching sensitivity was more significant in the first week for a longer time of use.

Which self-etch acidic composition may result in higher dental bonds at the long-term? A network meta-analysis review of in vitro studies.

OBJECTIVES: This review evaluated the effects of the acidic composition of self-etch (SE) adhesives at the long-term bond strengths to dentin and enamel. DATA: The review followed the PRISMA Extension Statement for network meta-analysis. Studies were identified by a systematic search in PubMed, Web of Science, and Scopus databases. STUDY SELECTION: The inclusion criteria were in vitro studies that evaluated bond strength data of samples analyzed at both immediate and long-term (after aging simulation) periods and that were bonded to sound dentin/enamel using SE adhesives, with at least one group of adhesives being based on 10-MDP (10-methacryloyloxy-decyl-dihydrogen-phosphate; control) and the other group being comprised of alternative acidic monomers. Statistical analyses were conducted using two methods: standard pairwise meta-analysis (SPMA) and Bayesian network meta-analysis (NMA). Heterogeneity was assessed by using the Cochran Q test and I2 statistics. RESULTS: From 5220 studies identified, 87 met the eligibility criteria and 83 were meta-analyzed. Seventeen adhesives were based on 10-MDP and 44 systems were based on alternative acids. The resin-dentin/enamel bonds were predominantly reduced after aging (∼84% of cases). From the SPMA findings, the following acidic compositions showed lower bond strength values (effect size: mean difference [MD] with 95% confidence interval [95% CI]) than 10-MDP: 4-META (MD -4.99, 95% CI: -7.21, -2.78; p<0.001); sulfonic acids (MD -9.59, 95% CI -12.19, -6.98; p<0.001); unspecified phosphate esters (MD -8.89, 95% CI -17.50, -0.28; p = 0.04); or mixed acids (MD -11.0, 95% CI -13.62, -8.38; p<0.001). The dental bonds were benefited from the presence of 10-MDP upon longer aging (>6 months). From the NMA probabilistic findings, adhesives based on 10-MDP and phosphonic acids ranked as having the best and the worst bonding potential to dentin, respectively. More than one composition (phosphonic acids and mixed acids) ranked similarly to 10-MDP in enamel. The studies scored as having moderate risk of bias (58.6%), followed by low (39.1%) and high (2.3%) risk of bias. CONCLUSION: 10-MDP is an outstanding acidic monomer that contributes to higher bonds to dentin at the long-term. In enamel, there is no evidence that one acidic composition prevails over the other. CLINICAL SIGNIFICANCE: The acidic composition of SE adhesives affects the resistance of dental bonds after simulated aging, with 10-MDP playing a significant role in the adhesion to dentin but not to the enamel. REGISTRATION NUMBER: This report is registered at the Open Science Framework (osf.io/urtdf).

Effects of dentinary contamination by endodontic irrigants on bonding strength of adhesive systems

This study aimed to evaluate if 2.5% sodium hypochlorite compromises the adhesion of bonding materials. The factors in the study were the irrigation solutions in two levels: 2.5% sodium hypochlorite and saline solution; and the adhesive systems used in three levels: three-step adhesive, universal adhesive, and two-step self-etch adhesive systems. The answer variable used was the microshear bond strength obtained through a universal testing machine and fracture mode. Six groups were obtained (n=10) : Etch-and-rinse/Saline (saline solution + 3-step adhesive system - Scotchbond Multipurpose, 3M ESPE); Universal/saline (saline solution + universal adhesive system ­ Prime&Bond,); Self-etch/saline (saline solution + 2-step self-etch adhesive systems - Clearfil SE Bond); Etch-and-rinse/Hypo (sodium hypochlorite 2,5% + 3-step adhesive system - Scotchbond Multiuso); Universal/Hypo (sodium hypochlorite 2,5% + universal adhesive system ­ Prime&Bond); Self-etch/Hypo (sodium hypochlorite 2,5% + 2-step self-etch adhesive system - Clearfil Se Bond). The specimens were obtained from 60 healthy bovine incisors. The crowns were separated from the roots, and the regularization of the buccal surface was performed. The groups received saline solution and 2.5% sodium hypochlorite for 30 minutes, respectively. A matrix of 1mm and 3mm oh height was stabilized by Scotch tape to obtain the resin sticks. Afterward, the bond strength test was performed in a universal testing machine at 1mm/min speed. The data were analyzed with normality Shapiro-Wilk, two-way ANOVA, and Tukey's tests (p<0.001). Etch-and-rinse and Self-etch adhesives presented the highest bond strength values after irrigation with saline solution and 2.5% sodium hypochlorite, respectively (P < 0.01). The irrigation with 2.5% sodium hypochlorite decreased the bond strength values of Etch-and-rinse and Universal (P < 0.01). On the other hand, 2.5% sodium hypochlorite improved the bond strength values of Self-etch (P < 0.01). In conclusion, 2.5% sodium hypochlorite negatively impacted the bond strength of Etch-and-rinse and Universal but improved the adhesion of Self-etch.

Effect of ultrasonic activation of the adhesive system on dentin tubule penetration and the pushout bond strength of fiber posts.

STATEMENT OF PROBLEM: Whether ultrasonic activation of the adhesive system improves dentin tubule penetration and the bond strength of fiber posts to root dentin is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effect of ultrasonic activation of 2 adhesive systems (etch-and-rinse and self-etch) and 1 glass ionomer cement on the dentin tubule penetration and pushout bond strength of fiber posts to root dentin. MATERIAL AND METHODS: Sixty maxillary central incisors were endodontically treated and divided into 6 groups (n=10) as per the post cementation strategy: etch-and-rinse, etch-and-rinse and ultrasonic, self-etch, self-etch and ultrasonic, glass ionomer cement, and glass ionomer cement and ultrasonic. The primers, the adhesives, and the glass ionomer cement were activated for 20 seconds each, and the fiber posts were cemented with a resin cement. Dentin tubule penetration was evaluated by confocal laser scanning microscopy and the pushout bond strength measured at 3 post locations: cervical, middle, and apical. The failure patterns were also described after pushout testing. RESULTS: Self-etch and ultrasonic showed higher dentin tubule penetration than the other cementation strategies (P<.05) and improved the bond strength values (P<.05), which were higher than etch-and-rinse and ultrasonic and glass ionomer cement and ultrasonic (P<.05). Adhesive failures at the cement and dentin interface were predominant in the etch-and-rinse, self-etch, and self-etch and ultrasonic groups. CONCLUSIONS: Ultrasonic activation improved the dentin tubule penetration of a self-etch adhesive system. The bond strength of fiber posts cemented with a self-etch adhesive system and a resin cement was improved after ultrasonic activation.

Intratubular penetration of endodontic sealers depends on the fluorophore used for CLSM assessment.

Root canal filling aims at eliminating empty spaces into the root canal system using biologically compatible materials. Three-dimensional root canal obturation must prevent or minimize the reinfection caused by microorganisms' leakage. This study aimed at evaluating whether fluorophore (Rhodamine or Fluo-3) influences the CLSM images of intratubular penetration of four endodontic sealers. Eighty bovine teeth were prepared using K files up to a size #70 and irrigated with 2.5% sodium hypochlorite. All roots were divided into eight groups (n = 10) according to the sealer and fluorophore used: AH Plus/Rhodamine, AH Plus/Fluo-3, Sealer Plus/Rhodamine, Sealer Plus/Fluo-3, Sealer Plus BC/Rhodamine, Sealer Plus BC/Fluo-3, Endosequence/Rhodamine, and Endosequence/Fluo-3. All roots were filled using cold lateral compaction technique. After 7 days, the roots were transversely sectioned, and three slices, one of each canal third, were obtained. Intratubular penetration was evaluated using CLSM. Sealer Plus BC/Rhodamine and Endosequence BC/Rhodamine presented higher intratubular penetration than AH Plus/Fluo-3 and Sealer Plus/Fluo-3 (p ˂ .05). The intragroup analysis showed similar intratubular penetration, regardless of the root third, except for the apical third in AH Plus/Fluo-3 and Sealer Plus BC/Fluo-3 groups. The type of fluorophore influences the calcium silicate sealers' tubular penetration but not of epoxy resin-based ones using CLSM. Bioceramic sealers should not be used associated with Rhodamine for CLSM evaluation. RESEARCH HIGHLIGHTS: The type of fluorophore influences the calcium silicate sealers' tubular penetration but not of epoxy resin-based ones when CLSM is used for assessment. Bioceramic sealers should not be used associated with Rhodamine.

Esthetic recovery of teeth presenting fluorotic enamel stains using enamel microabrasion and home-monitored dental bleaching.

This clinical report describes the enamel microabrasion technique for removing maxillary and mandibular hard fluorotic enamel stains followed by home-monitored home dental bleaching. The removal of fluorotic enamel stains utilized macroabrasion with a water-cooled, fine-tapered 3195 FF diamond bur followed microabrasion with the application of Prema Compound (Premier Dental Products Co, Norristown, PA, USA). Home-monitored dental bleaching was performed 14 days after enamel microabrasion using a 10% carbamide peroxide gel for 2 h/day. The wearing time of the acetate tray/dental bleaching was quantified by a microsensor from TheraMon microelectronic system (Sales Agency Gschladt, Hargelsberg, Austria) that was completely embedded in the acetate trays. The teeth were bleached effectively during 23 days. The mean wearing time of the acetate trays/dental bleaching product was 1.54 h/day, for the upper and lower arches. The patient reported satisfaction with the treatment. The association of enamel microabrasion and home dental bleaching was an excellent clinical treatment for teeth affected with enamel fluorosis.

Dental bleaching on teeth submitted to enamel microabrasion 30 years ago-a case report of patients' compliance during bleaching treatment.

OBJECTIVES: The present dental bleaching case report describes a new method that precisely quantifies the daily wearing-times of the bleaching product by inserting a microsensor in the acetate custom tray. The bleaching efficacy was also discussed since the patient was previously submitted to enamel microabrasion. METHODS: The patient was submitted to enamel microabrasion in 1987, and bleaching treatment was performed in 2005. In 2017, re-bleaching was executed using 10% peroxide carbamide. The electronic microsensor, TheraMon (TheraMon® microelectronic system; Sales Agency Gschladt, Hargelsberg, Austria), was embedded in the labial region of the upper and lower acetate trays to evaluate the wearing-times of the acetate trays/bleaching product. The patient was instructed to wear the tray for 6 to 8 h/day while sleeping. After 24 days of bleaching treatment, the data obtained from the TheraMon electronic devices was collected and interpreted. RESULTS: The patient did not entirely follow the bleaching treatment as recommended, as there was no evidence of use of the upper and lower trays for some days; additionally, the bleaching product was used for shorter and longer periods than was instructed. CONCLUSIONS: The TheraMon microeletronic device precisely measured the wearing-times of the acetate tray/bleaching product during the bleaching treatment. Teeth submitted to enamel microabrasion presented with a healthy clinical appearance after 30 years. CLINICAL SIGNIFICANCE: Measuring the length and frequency of use of an acetate tray/bleaching product can be important to clinicians and patients for obtaining a controlled and adequate bleaching treatment.

A utilização do DSD (Digital Smile Design) para a otimização da estética dental / The use of DSD (Digital Smile Design) for the optimization of the dental esthetics

Atualmente, o DSD (digital smile design) tem sido utilizado como um recurso de grande destaque para a Odontologia Estética. O uso de um software pode facilitar e implementar através de simulações o tratamento reabilitador estético, fazendo com que haja maior entendimento do paciente sobre o procedimento e seus resultados, bem como evitando equívocos que possam ocorrer durante o tratamento. A técnica consiste em analisar as proporções faciais e dentárias de cada paciente e suas relações com dentes, lábios e gengivas por meio de fotografias digitais e vídeos. Com isso, são realizados desenhos seguindo métodos específicos que podem ser apresentados de maneira simples, compreensível e cativante para o paciente(AU)

Nowadays, the DSD (digital smile design) has been used as a great resource for aesthetic restorative dentistry. Through simulations, the use of a software can facilitate and implement aesthetics rehabilitation treatment, helping the patient to have a better understanding of the procedure and its outcomes, and also avoiding misunderstandings that may occur during the treatment. This technique consists in analyzing facial and dental proportions of each patient and the relations with their teeth, lips and gum through digital photograph and movies. Therefore, designs are made following specific methods that can be presented in a simple way, understandable and engaging for the patient(AU)

Two-Year Clinical Evaluation of a Nanofilled Etch-and-Rinse and a Self-Etch Adhesive System Containing MDPB and Fluoride in Non-carious Cervical Lesions.

OBJECTIVES: The aim of this clinical study was to evaluate the performance of restorations for non-carious cervical lesions performed with a two-step etch-and-rinse or with a two-step self-etch adhesive. MATERIALS AND METHODS: The teeth to be restored (15 patients, N = 90 restorations) were randomly assigned into 3 groups (n = 30), according to the adhesive system: group 1 (G1): Peak LC Bond; group 2 (G2): Clearfil Protect Bond; and group 3 (G3): prior selective acid etching of the enamel margins before bonding with Clearfil Protect Bond. The NCCLs were restored with Amelogen Plus composite resin. Two calibrated examiners evaluated the restorations using modified US Public Health Service criteria. The data of retention, marginal integrity, and marginal discoloration were analyzed using the Kruskal-Wallis and Wilcoxon tests. RESULTS: There were no significant differences in clinical performance among the groups for the variables: retention, marginal integrity, and marginal discoloration after 1 year and 2 years. The alpha rates after 2 years were: 93.3% for G1 and 96.7% for G2 and G3 for retention; 93.3%, 100%, and 90% for G1, G2, and G3 for marginal discoloration; 86.7%, 96.7%, and 90% for G1, G2, and G3 for marginal integrity, respectively. CONCLUSIONS: The adhesives presented similar clinical performance at the end of 2 years. Also, the prior etching with phosphoric acid did not significantly improve the clinical performance of self-etch adhesive.

Three-Year Clinical Evaluation of Class I Restorations in Posterior Teeth. Effects of Two Adhesive Systems.

This longitudinal study evaluated the clinical performance of 97 direct class I resin composite restorations after 3 years. The restorations were performed using 2 types of adhesive systems: (1) Adper™ Single Bond Plus (SB) (3M ESPE, 3mespe.com), which is a two-step etch-and-rinse system, and (2) Adper Scotchbond™ SE (SE) (3M ESPE), which is a two-step self-etching system. Two calibrated examiners evaluated the restorations using modified US Public Health Service criteria. The materials were applied following the manufacturer's instructions, and 15 patients received at least one of the two adhesive systems. The restorations were evaluated 7 days after placement (baseline) and again after 3 years. Statistical analysis was performed using a proportion t-test at a significance level of 5% (P < .05). At baseline, all restorations received an Alpha score for the variable marginal discoloration and marginal integrity. After 3 years, marginal discoloration received an Alpha score for 53.19% of the restorations performed with SB and 52.08% with SE. Marginal integrity was rated as Alpha for 65.96% and 68.75% of the restorations with SB and SE systems, respectively. The remaining restorations received Bravo scores for all variables. Eight restored teeth presented postoperative sensitivity at baseline (5 SB; 3 SE), but no sensitivity was found after 3 years. No secondary caries was verified. No statistically significant differences were observed between the teeth restored with the SB and SE systems for marginal discoloration (P = .7880) and marginal integrity (P = .8132) after 3 years. Direct class I resin composite restorations performed with a two-step etch-and-rinse and a two-step self-etching adhesive system demonstrated satisfactory clinical performance after 3 years.

Clinical Comparison of At-Home and In-Office Dental Bleaching Procedures: A Randomized Trial of a Split-Mouth Design.

The objective of this split-mouth clinical study was to compare a combination of in-office and at-home dental bleaching with at-home bleaching alone. Two applications of in-office bleaching were performed, with one appointment per week, using 38% hydrogen peroxide. At-home bleaching was performed with or without in-office bleaching using 10% carbamide peroxide in a custom-made tray every night for 2 weeks. The factor studied was the bleaching technique on two levels: Technique 1 (in-office bleaching combined with home bleaching) and Technique 2 (home bleaching only). The response variables were color change, dental sensitivity, morphology, and surface roughness. The maxillary right and left hemiarches of the participants were submitted to in-office placebo treatment and in-office bleaching, respectively (Phase 1), and at-home bleaching (Phase 2) treatment was performed on both hemiarches, characterizing a split-mouth design. Enamel surface changes and roughness were analyzed with scanning electron microscopy and optical interferometry using epoxy replicas. No statistically significant differences were observed between the bleaching techniques for either the visual or the digital analyses. There was a significant difference in dental sensitivity when both dental bleaching techniques were used, with in-office bleaching producing the highest levels of dental sensitivity after the baseline. Microscopic analysis of the morphology and roughness of the enamel surface showed no significant changes between the bleaching techniques. The two techniques produced similar results in color change, and the combination technique produced the highest levels of sensitivity. Neither technique promoted changes in morphology or surface roughness of enamel.

Surface effects after a combination of dental bleaching and enamel microabrasion: An in vitro and in situ study.

This study evaluated the effects of combining enamel microabrasion and dental bleaching on the physical properties of enamel, using in vitro and in situ conditions and evaluating surface roughness, enamel microhardness and scanning electron microscopy images. One hundred sound bovine teeth were sectioned and cut into discs and randomly divided into 10 study groups (n=10). The results were submitted to Analysis of Variance (ANOVA) for repeated measures, followed by the Tukey test, with significance at 5%. Enamel surface roughness was significantly influenced by microabrasion, regardless of being combined with dental bleaching, for both HS (Human Saliva) or AS (Artificial Saliva) condition. Enamel microhardness was significantly decreased in the groups in which enamel microabrasion was performed, regardless its combination with dental bleaching; although storage in HS reestablished the initial enamel microhardness. It was concluded that dental bleaching does not cause major damage to microabraided enamel, and that only human saliva recovered the initial enamel microhardness.

Platform-Switching for Cemented Versus Screwed Fixed Dental Prostheses: Reliability and Failure Modes: An In Vitro Study.

PURPOSE: The aim of this study was to evaluate the probability of survival of cemented and screwed three-unit implant-supported fixed dental prostheses (ISFDP) using different implant-abutment horizontal matching configurations (regular vs switching platforms). METHODS: One hundred and sixty-eight implants with internal hexagon connection (4 mm diameter, 10 mm length, Emfils; Colosso Evolution System, Itú, SP, Brazil) were selected for this study according to the horizontal implant-abutment matching configuration (regular or switching) and retention method and divided in four groups (n = 21 per group) as follows: 1) regular platform cemented (IRC); 2) or screw-retained (IRS); 3) switched-platform cemented (ISC); or 4) screw-retained (ISS). Regular and platform-switched abutments (Colosso evolution, 4 mm and 3.3 mm, respectively) were torqued, and 84 three-unit metal bridges were fabricated (first molar pontic). Implants were embedded in polymethyl-methacrylate resin and subjected to step-stress accelerated life testing in water. Weibull distribution was used to determine the probability of survival for a mission of 100,000 cycles at 400 N (90% two-sided confidence intervals). Polarized light and scanning electron microscopes were used for fractographic analysis. RESULTS: The ß values of 0.50, 1.19, 1.25, and 1.95 for groups IRC, IRS, ISC, and ISS respectively, indicated that fatigue accelerated the failure for all groups, except IRC. The cement-retained groups presented significantly higher probability of survival (IRC - 98%, ISC - 59%) than screw-retained groups (IRS - 23% and ISS - 0%). Screw-retained FDPs exclusively failed by abutment-screw fractures, whereas cement-retained presented implant/screw/abutment fractures. CONCLUSIONS: The probability of survival of cement-retained ISFDP was higher than screw-retained, irrespective of implant-abutment horizontal configuration.

Effect of Diamondlike Carbon Coating on Reliability of Implant-Supported Crowns.

PURPOSE: To evaluate the effect of diamondlike carbon (DLC) coating on abutments and/or abutment screws on the reliability, characteristic strength, and Weibull modulus of implant-supported single crowns. MATERIALS AND METHODS: Seventy-two external hexagon implants (Emfills Implant 4 mm diameter, 10 mm length, Emfills) were divided into four groups (n = 18 each), according to the presence or not of a DLC coating in the abutment and/or abutment screw, as follows: abutment without coating, screw without coating (AwcSwc); abutment without coating with coated screw (AwcSC); abutment coated with noncoated screw (ACSwc), and coated abutment with coated screw (ACSC). Abutments and screws were evaluated with scanning electron microscopy. The specimens were subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and reliability for a mission of 100,000 cycles at 150 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used for fractographic analysis. RESULTS: For a mission of 100,000 cycles at 150 N, reliability was 0.45 (0.20 to 0.67), 0.12 (0.00 to 0.47), 0.56 (0.17 to 0.82), and 0.44 (0.07 to 0.77) for AwcSwc, AwcSC, ACSwc, and ACSC, respectively. The probability Weibull calculation showed a Weibull modulus (m) of m = 5.50, m = 11.64, m = 16.96, and m = 15.08 and the characteristic strengths (η, which indicates the load at which 63.2% of the specimens of each group fail) of η = 202.67 N, ŋ = 206.64 N, ŋ = 192.54 N, and ŋ = 203.59 N for AwcSwc, AwcSC, ACSwc, and ACSC, respectively. Abutment screw fracture was the chief failure outcome in all groups. CONCLUSION: Characteristic strength values were not different among groups; neither was reliability. However, an increase in Weibull modulus (indicating low variability of the results) was observed with DLC coating of abutment or screw or both.

Effect of long-term storage on nanomechanical and morphological properties of dentin-adhesive interfaces.

INTRODUCTION: To evaluate the influence of storage time on the elastic modulus, micromorphology, nanoleakage, and micromechanical behavior of the dentin-adhesive interfaces of five adhesive systems (Scotchbond Multi-Purpose, Clearfil SE Bond, One Up Bond F, Adper Easy One, and Filtek LS Adhesive) after 24h (T0) and 12 months (T1). METHODS: Fifty teeth were restored and distributed according to each adhesive system (n=10). At least four specimens were obtained from each tooth. One specimen was evaluated under SEM to obtain the micromorphology of dentin-adhesive interface (DAI). Two specimens were used to assess nanoleakage, one tested in T0 and the other in T1. The last specimen was used for nanoindentation, in T0 and T1, to obtain the initial and final mechanical properties of DAI structures. Two non-restored teeth were evaluated under SEM to obtain the dentin morphology. Laboratorial data were used to build 15 finite element models to assess the maximum principal stress in each time of analysis. RESULTS: Storage resulted in hydrolysis of the dentin-adhesive interfaces for all groups. Silver impregnation increased for all groups after 1 year storage (p<.05), except for Clearfil SE Bond. In general, a decrease in elastic modulus values was observed for all groups from T0 to T1 (p<.05), mainly at the hybrid layer. The FEAs showed higher stress levels at T1 than T0 simulations for all adhesives. CONCLUSION: At T1, degradation occurred at the dentin-adhesive interface formed by all adhesives, and the intensity of degradation differed depending on the type of adhesive system used. The interface formed by the self-etching primer containing the 10-MDP functional monomer showed the highest stability among the adhesive systems after 12 months of storage.

Flexural strength of composites: effects of the activationtechniques and fiber reinforcement / Resistência à flexão de compósitos: efeitos das técnicas de fotopolimerização e reforço de fibra

Objetivo: Avaliar a resistência à flexão de compósitos diretos (Charisma) e indiretos (Solidex), com ou sem reforços de fibra (Ribbond), polimerizados com LED ou Stroboscopic Xenon Light. Material e métodos: Barras de resina feitas com ou sem reforços de fibra,com 25 mm x 2 mm x 2 mm foram distribuídas emgrupos (n = 10): GDL- Resina Direta / LED; GDX ResinaDireta / Stroboscopic Xenon; GDFL- Resina Direta / Fibra / LED; GDFX- Resina Direta / Fibra /Stroboscopic Xenon; GIL- Resina Indireta / LED; GIXResinaIndireta / Stroboscopic Xenon; GIFL- Resina Indireta / Fibra / LED; GIFX- Resina Indireta / Fibra /Stroboscopic Xenon. Os espécimes foram conectados a uma máquina de teste universal e submetidos a uma carga de compressão (2 kN). Resultados: Os resultados obtidos foram submetidos ao teste de Análise de Variância (nível de significância de 5%) e teste de Tukey (p < 0,01). A resistência à flexão dos grupos que utilizaram reforço de fibra de polietileno(96,39) foi semelhante (p = 0,58) aos grupos sem reforço de fibras (92,47). Os compósitos diretos(107,79) mostraram maiores valores de resistência àflexão do que os compósitos indiretos (81,07), e a luze a polimerização com luz stroboscópica de xenônio(108,71) deu melhores resultados de resistência àflexão do que com LED (80,15), para ambos os tipos de compósitos estudados. Conclusão: O reforço de fibranão melhorou a resistência à flexão dos compósitos, compósitos diretos apresentaram maiores valores de resistência à flexão, e a luz estroboscópica de xenônio mostrou melhores resultados de resistência à flexão.

Objectives: To evaluate the flexural strength of direct(Charisma) and indirect (Solidex) composites, withor without fiber reinforcements (Ribbond), curedwith LED or Stroboscopic Xenon Light. Materialand Methods: Resin bars made with or withoutfiber reinforcements, with 25mm x 2mm x 2mmwere distributed in groups (n=10): GDL– DirectResin/LED; GDX–Direct Resin/Stroboscopic Xenon;GDFL– Direct Resin/Fiber/LED; GDFX– Direct Resin/Fiber/Stroboscopic Xenon; GIL– Indirect Resin/LED;GIX– Indirect Resin/Stroboscopic Xenon; GIFL–Indirect Resin/Fiber/LED; GIFX– Indirect Resin/Fiber/Stroboscopic Xenon. The specimens wereconnected to a universal test machine and submittedto a compression load (2 kN). Results: The obtainedresults were submitted to Analysis of Variance tests(p < 0.01), and Tukey (5% significance level)tests. The flexural strength of groups that usedpolyethylene fiber reinforcement (96.39) was similar(p = 0.58) to group without fiber reinforcement(92.47). Direct composites (107.79) showed highervalues of flexural strength than indirect composites(81.07), and stroboscopic xenon light curing(108.71) resulted in better flexural strength resultsthan LED (80.15), for both kinds of compositesexperimented. Conclusion: The fiber reinforcementdid not improve the composites’ flexural strength,direct composites showed higher flexural strengthvalues, and stroboscopic xenon light showed betterflexural strength results.

Microabrasion in tooth enamel discoloration defects: three cases with long-term follow-ups.

Superficial irregularities and certain intrinsic stains on the dental enamel surfaces can be resolved by enamel microabrasion, however, treatment for such defects need to be confined to the outermost regions of the enamel surface. Dental bleaching and resin-based composite repair are also often useful for certain situations for tooth color corrections. This article presented and discussed the indications and limitations of enamel microabrasion treatment. Three case reports treated by enamel microabrasion were also presented after 11, 20 and 23 years of follow-ups.