In vitro effect of two resin based materials for treating initial caries lesion around braces, under cariogenic challenge.

Background: Orthodontic treatment makes the patient susceptible to the development of white spot lesions (WSL) due to the greater accumulation of bacterial plaque. The purpose of this in-vitro study was to evaluate the preventive effect of two resin materials on the incidence of these lesions in the region adjacent to the fixed bracket bonded under a WSL-treated area by two resin materials. Material and Methods: 36 extracted human molars presenting natural WSL were included. They were randomly divided into 2 groups for intervention: IC (Infiltration resin Icon®) and PS (resin sealant Pro Seal ®). Braces were bonded just above the WSL. The enamel surface around the brace was treated by one of the tested materials, leaving another part to be control. The samples were submitted again to a cariogenic challenge. The exposed enamel non-treated area from booth groups comprised the control group (E). For morphological analysis, confocal images were taken at baseline, after treatment, and after pH cycling of each sample. Lesion depth were measured (µm) and compared to the enamel thickness to calculate a demineralization index. All groups were compared using the Kruskal Wallis test and Dunn's post-test. Results: PS group showed the lowest demineralization index (0.27 µm) when compared to the control area (0.39 µm) (p<0.05). IC presented a slightly higher percentage of lesions when compared to PS, however, did not differ significantly from the control exposed area. Conclusions: The resin sealant Pro Seal® had a positive protective effect under white spot environmental area and Icon® infiltrant, although showed some protection, did not statistically differ from controls. Key words:Dental Caries, Orthodontics, Dental Enamel, Sealants.

Effect of Er:YAG Laser and Association of Protocols on the Demineralized Enamel Microhardness.

Objective: The aim of this study was to analyze the microhardness of demineralized enamel following different treatments (fluoride varnish, Er:YAG laser, and Er:YAG laser associated with fluoride varnish). Methods: Forty-eight enamel blocks (4 × 4 × 7 mm) were divided into six groups (n = 8): (S) Sound; (DE) Demineralized; (DED) DE + Duraphat® 5% (fluoride varnish); (DEL20) DE + Er:YAG laser (20 mJ pulse mode; 0.20 W; 10 Hz; 60 sec; 1.18 J/cm2; 11.83 W/cm2); (DEL50) DE + Er:YAG laser (50 mJ pulse mode; 0.50 W; 10 Hz; 60 sec; 2.95 J/cm2; 29.58 W/cm2); (DEL20D) DE + Er:YAG laser (20 mJ) + Duraphat 5%. The irradiation was performed at 1 mm distance from the surface using a tip (AS7066X, L-14 mm, D-1.3 mm in diameter) in water/air spray refrigeration (level 6). The enamel blocks were submitted to pH cycling (4 h into DES solution +20 h into RE solution for 8 days and the solutions were changed every day). Knoop microhardness was measured (50 g/15 sec, six readings per sample) and data were analyzed by Kruskal-Wallis test at 5% significance. Results: After treatments, DF group showed higher microhardness values than all the groups. Also, DEL20D group showed similar results with H group according to the microhardness analysis (p < 0.05). Conclusions: It could be concluded that Duraphat 5% treatment showed better results when compared with all tested groups, however, the association of Er:YAG Laser 20 with Duraphat 5% also showed promising results.

Reliability of ICDAS to Detect Occlusal Caries among Master's Degree students of Dentistry / Confiabilidade do ICDAS para Detectar Cárie Oclusal Entre Mestrandos de Odontologia

The objective of this study was to investigate the reproducibility of the International System for the Detection and Evaluation of Caries (ICDAS) for the diagnosis of caries by students of the Master's Degree in Dentistry (n = 25). The occlusal surfaces of human third molars (n = 14) were evaluated by twenty-five (n = 25) students using the ICDAS index and later a questionnaire was applied on demographic and professional context data. The dental crowns were sectioned in mesial to distal direction to obtain slices of 1mm in thickness which were observed in a stereomicroscope (40X) to identify the greatest extension of caries lesion. Data were analyzed by the Chi-Square, Fisher's Exact and Spearman's Correlation Coefficient at a significance level of 5%. There was an influence in the diagnosis of caries among students and teeth, where the majority of those who declared themselves to be safe missed the diagnosis. There was variability between the diagnosis and the proposed treatment for caries, with a better diagnosis for tooth VII and less for X; greater fit for treatment of teeth XIII, XIV and lower for IV, VI. The histological cut showed that the teeth were more affected by caries than the ICDAS. It was concluded that the ICDAS reproducibility was partially satisfactory when the occlusal surface was evaluated by the master's degree students. (AU).

Este trabalho teve o objetivo de investigar a reprodutibilidade do Sistema Internacional de Detecção e Avaliação de Cárie (ICDAS) para o diagnóstico da cárie, por estudantes de curso de Mestrado em Odontologia (n=25). As superfícies oclusais de terceiros molares humanos (n=14) foram avaliadas por vinte e cinco (n=25) estudantes, utilizando o índice ICDAS, e posteriormente foi aplicado questionário sobre dados demográficos e de contexto profissional. As coroas dentárias foram seccionadas no sentido mésio distal para obter fatias de 1 mm de espessura, que foram observadas em estereomicroscópio (40X) para identificar a maior extensão da lesão de cárie. Os dados foram analisados pelos Testes Qui-Quadrado, Exato de Fisher e Coeficiente de Correlação de Spearman, em nível de significância de 5%. Houve influência do grau de instrução dos estudantes no diagnóstico da cárie em relação ao dente avaliado e a maioria que se declarou segura errou o diagnóstico. Houve variabilidade entre o diagnóstico e o tratamento proposto para a cárie, com maior acerto para diagnóstico do dente VII e menor para o X; maior acerto para tratamento dos dentes XIII, XIV e menor para IV, VI. O corte histológico mostrou que os dentes estavam mais comprometidos pela cárie que o ICDAS. Concluiu-se que a reprodutibilidade do ICDAS foi satisfatória quando a superfície oclusal foi avaliada pelos mestrandos. (AU).

Microhardness of bovine enamel after different fluoride application protocols.

The aim of the present study was to evaluate microhardness, mineral recovery and the enamel surface after the application of topical fluoride to artificial dental caries. Twenty-five bovine enamel blocks were prepared for artificial caries-like lesions and randomly divided into five groups (n=5): untreated (C control), 1.23% acidulated phosphate fluoride gel (APG), 2% neutral fluoride gel (NFG), 1.23% acidulated fluoride mousse (AFM) and fluoride varnish (5% Duraphat, DFV). Knoop microhardness (KHN) was evaluated after 7 and 14 days of treatment as well as 1 week after 28 days of treatment. Electron and confocal microscopy and energy dispersive spectroscopy were performed. KHN data were treated with two-way ANOVA (material×time) and Tukey's test at a 5% significance level. Differences were found among groups over time (p<0.001). Microhardness varied after 7 and 14 days of treatment and remained stable 1 week after 28 days of treatment. Mineral recovery and enamel topography varied among groups, with the fluoride varnish achieving the most uniform topography.

Effect of Polyacrylic Acid Conditioning on the Longevity of Bonding of Self - Adhesive Resin Cement to Dentin / Efeito do Condicionamento com Ácido Poliacrílico na Longevidade da Adesão de Cimento Resinoso Autoadesivo à Dentina

Bonding of fiber posts using self-adhesive resin cement to radicular dentin is controversial. The aim was to evaluate the effect of conditioning of polyacrylic acid on the longevity of bonding of self-adhesive resin cement to dentin. Thirty six single rooted pre molars were divided into 3 groups (n=12) ARC: ScotchBond Multi Purpose + RelyX™ARC; U: RelyX™U200; PU: 11.5% Polyacrylic acid + RelyX™U200. After conditioning of the dentin, the resin cement and the post were inserted and light-activated for 60s (1200mw/cm2 ) and stored in distilled water (24h/37ºC). Two discs of 1 mm thickness were obtained from each root-third and tested in push-out (0.5mm/min) after 24 hours and 6 months. For statistical purposes, the data from the root-thirds were grouped and the bond strength (in MPa) was analyzed using Two-Way Analysis of Variance and Tukey's post-hoc test at 5%. The power of the test was calculated. The bonding of the U at 6 months was higher than PU at both times (p<0.001). There were no differences for time (p=0.153) or for the interaction of treatment x time (p=0.090). Adhesive fractures between the cement and dentin were prevalent. The power test was 0.97. The bonding of the RelyX™U200 was influenced by the dentin pre-treatment with poliacrylic acid and the bonding of all groups remained stable for 6 months. (AU).

A adesão de pino de fibra de vidro com cimento resinoso autoadesivo à dentina é controversa. Foi objetivo avaliar o efeito do condicionamento da dentina com ácido poliacrílico na longevidade da adesão de cimento resinoso autoadesivo. Trinta e seis raízes de pré-molares uni radiculados foram divididas em 3 grupos (n=12) ARC: ScotchBond Multi Purpose + RelyX™ARC; U: RelyX™U200; PU: Ácido poliacrílico 11,5% + RelyX™U200. Após condicionamento da dentina, o cimento resinoso e o pino de fibra de vidro foram inseridos, fotoativados por 60s (1200mw/cm2 ) e armazenados em água destilada (24h/37ºC). Dois discos de dentina de 1 mm de espessura foram obtidos de cada terço radicular e testados em push-out (0.5mm/min) após 24 houras e 6 meses. Para análise estatística, os dados dos terços radiculares foram agrupados e resistência adesiva (em MPa) analisada por Análise de Variância de dois fatores e teste de Tukey a 5%. O poder do teste foi calculado. A adesão de the U após 6 meses foi maior que a de PU nos dois períodos (p<0,001). Não houve diferença para o fator tempo (p=0,153) nem para a interação tratamento x tempo (p=0,090). Fraturas adesivas prevaleceram entre cimento e dentina. O poder do teste calculado foi de 0,97. A adesão do RelyX™U200 foi influenciada pelo pré-tratamento da dentina com ácido poliacrílico e a adesão de todos os grupos se manteve estável até 6 meses. (AU).

Adesão do Selante Clinpro™ XT à Superfície Oclusal de Molares Decíduos: Avaliação Longitudinal / Clinpro ™ XT Sealant Adhesion to the Occlusal Surface of Primary Molars: Longitudinal Evaluation

The study aims to evaluate the bond strength of sealants on deciduous molars. Clinpro ™ XT, Vitremer ™, Fluroshield and Optibond FL materials were applied to the occlusal surface of 40 deciduous lower molars (n = 5). The teeth were prepared for the micro tensile test, obtaining a specimen in a stick format with a cross-sectional area of 0.8 mm2 . After 24 hours and 6 months of restorative procedures, the specimens were traversed in universal test machine. The statistical analysis used the tooth as experimental unit, considering the adhesive and mixed fractures data, through Variance Analysis of repeated measures and Tukey tests (α = 0.05). There was a difference among the adhesion of the materials in 24 h, with higher union strength for Optibond FL (31.20 ± 1.36 MPa), significantly higher than that of Clinpro ™ XT (20.23 ± 1.16 MPa), Fluroshield (24.61 ± 2.76 MPa) and Vitremer™ (21.31 ± 2.32 MPa), which were similar. After 6 months of storage, the Clinpro ™ XT bond strength remained (22.18 ± 2.91 MPa), Optibond FL decreased (20.77 ± 1.53 MPa), but remained similar to that of Clinpro ™ XT in 6 months. The lowest adhesion values at 6 months were of Fluroshield (11.14 ± 1.98 Mpa) and Vitremer (5.29 ± 0.58 Mpa). It was concluded that the bond strength of the sealants to the occlusal surface of the deciduous molars was influenced by the material, with Clinpro ™ XT being the only material that maintained the bond strength values after 6 months. (AU).

O presente estudo teve como objetivo avaliar a adesão de selantes em molares decíduos. Os materiais Clinpro™ XT, VitremerTM, Fluroshield e Optibond FL foram aplicados na superfície oclusal de 40 molares inferiores decíduos (n=5). Os dentes foram preparados para o ensaio de microtração, com obtenção de corpo-de-prova em formato de palito com área de seção transversal de 0,8 mm2 . Após 24 horas e 6 meses da realização dos procedimentos restauradores, os espécimes foram tracionados em máquina de ensaio universal. A análise estatística usou como unidade experimental o dente, considerando os dados de fraturas adesivas e mistas, pelos testes de Análise de Variância de medidas repetidas e Tukey (α=0,05). Houve diferença entre a adesão dos materiais em 24 h, com maior resistência de união para o Optibond FL (31,20 ±1,36 MPa), significativamente maior que a do Clinpro™ XT (20,23 ±1,16 MPa); Fluroshield (24,61 ±2,76 MPa) e VitremerTM (21,31 ±2,32 MPa) foram semelhantes. Decorridos 6 meses de armazenamento, a resistência de união do Clinpro™ XT se manteve (22,18 ±2,91 MPa) e a do Optibond FL diminuiu (20,77 ±1,53 MPa) mas se manteve semelhante à do Clinpro™ XT em 6 meses. Os menores valores de adesão em 6 meses foram do Fluroshield (11,14 ±1,98 Mpa) e do Vitremer (5,29 ±0,58 Mpa). Concluiu-se que a resistência de união dos selantes à superfície oclusal dos molares decíduos foi influenciada pelo material, sendo o Clinpro™ XT o único material que manteve os valores de resistência de união após 6 meses. (AU).

Effects of different treatments on chemical and morphological features of eroded dentin.

To evaluate the treatment of eroded dentin (Sensodyne Repair & Protect™, Er:YAG laser and combinations). The occlusal surfaces of 25 third molars were sectioned 1.5 mm in thickness. After an erosion cycle (5 min in demineralizing solution + 3 h in remineralizing solution; six cycles a day for 8 days), the samples were divided into five groups (n = 5): (E) erosion - control; (ES) erosion + Sensodyne Repair & Protect (NovaMin); (EL) erosion + Er:YAG laser (40 mJ, 10 Hz, 0.4 W, 50 µs, 3.1 J/cm2, 63 W/cm2); (ELS) erosion + Er:YAG laser + Sensodyne; and (ESL) erosion + Sensodyne + Er:YAG laser. Following storage in ultrapure water (37 °C/14 days), the Ca/P ratio was evaluated by EDXRF and the morphology surfaces examined in SEM. The percentage of exposed dentin tubules was calculated. One-way analysis of variance and Tukey's test at 5% were used to treat the data. The Ca/P ratio was higher in E and ES groups. More exposed dentin tubules were found in E group and less exposed tubules were found in the ES group (p < 0.0001). When the toothpaste and laser were combined, the number of occluded dentin tubules was higher when laser was performed first (ELS). A positive effect was found when the laser and toothpaste were combined.

Multiple Adhesive Layering Influence on Dentin Bonding and Permeability.

The aim was to evaluate the effect of the number of layers on the microtensile bond strength (µTBS), permeability and nanoleakage of an etch-and-rinse adhesive (Adper Single Bond 2). Different numbers of layers (1, 2 and 4) were applied on dentin susbstrate. Specimens were obtained and tested for µTBS. Stick-shaped samples were analysed by scanning electron microscope, to observe silver nitrate penetration. One-way ANOVA and Tukey tests were applied (α=0.05) for µTBS values. The fracture mode was evaluated under a stereomicroscope and a scanning electron microscope (SEM). Groups with two and four layers of bond showed higher µTBS to dentin and they also showed lower adhesive permeability than ONE layer. The silver nitrate uptake occurred in the hybrid layer in practically all groups. Fracture occurred predominantly at the mixed interface. The authors recommend the application of more than one layer of Adper Single Bond 2, because a single layer showed lower µTBS and higher permeability values.

Push-out bond strength of different translucent fiber posts cemented with self-adhesive resin cement.

PURPOSE: Evaluate the bond strength of different translucent fiber posts in the cervical, middle, and apical root thirds cemented with self-adhesive resin cement. MATERIALS AND METHODS: Sixty single-rooted teeth were randomly divided into five groups according to the fiber post used: Reforpost (opaque [control]), exacto, white post, radix, and Macro-Lock Illusion X-RO. The roots were subjected to chemomechanical preparation and cemented with self-adhesive resin cement. The teeth were sectioned into slices of the different root thirds and tested for bond strength (push-out). Two-way analysis of variance and Bonferroni test were used to verify statistical differences between groups (P < 0.05). RESULTS: No significant difference between the root thirds was detected (P > 0.05). However, the performance of the posts demonstrated a significant difference (P < 0.05). RDX had a lower performance in the apical third (P < 0.05). The other fiber posts had the same performance irrespective of the root third evaluated. The predominant failure pattern was adhesive between resin cement and root dentin. CONCLUSION: In general, the different translucent fiber posts showed the same performance. Yet, translucent fiber posts did not show superior bond strength compared with the opaque fiber post in any of the root thirds evaluated.

Influence of Surface Treatments and Adhesive Systems on Lithium Disilicate Microshear Bond Strength.

The purpose of this study was to evaluate the microshear bond strength of ceramic prosthetic structures reinforced by lithium disilicate cemented with resin cement under conditions of different surface treatments and adhesive systems. Seventy-two rectangular blocks of lithium disilicate (6.5 mm long × 5 mm wide × 1 mm thick) were fabricated, air abraded with 50-µm Al2O3 particles and divided into six groups (n=12) depending on the surface pretreatments. The groups were as follows: 10HF/S/SBM: 10% hydrofluoric acid etched for 20 s (10HF) + silane (S) + Adper Scotchbond Multi-Purpose (SBM); 10HF/S/SB: 10HF + S + Single Bond Universal (SB); 10HF/SBM; 10HF/SB; S/SBM and S/SB. Two 1-mm-long plastic tubes were placed on the specimens, filled with RelyX ARC resin cement and cured for 20 s per tube. The plastic tube was removed, and the microshear bond strength was tested. Data were submitted to analysis of variance and Tukey's tests (α=0.05). Fractured specimens were observed under optical microscopy. For both adhesives, the bond strengths (MPa) of groups treated with acid-etching and silane (10HF/S/SB: 24.82, 10HF/S/SBM: 24.90) were higher (p<0.001) than those of groups treated with acid-etching (10HF/SB: 16.47, 10HF/SBM: 19.94) only or only silane (S/SB: 18.42, S/SBM: 13.24). All groups showed a predominance of failure adhesive. The silanization should be a clinical step in cementing ceramic structures reinforced by lithium disilicate, even with the application of universal adhesive that contains silane in its formulation.

Influence of Surface Treatments and Adhesive Systems on Lithium Disilicate Microshear Bond Strength

Abstract The purpose of this study was to evaluate the microshear bond strength of ceramic prosthetic structures reinforced by lithium disilicate cemented with resin cement under conditions of different surface treatments and adhesive systems. Seventy-two rectangular blocks of lithium disilicate (6.5 mm long × 5 mm wide × 1 mm thick) were fabricated, air abraded with 50-μm Al2O3 particles and divided into six groups (n=12) depending on the surface pretreatments. The groups were as follows: 10HF/S/SBM: 10% hydrofluoric acid etched for 20 s (10HF) + silane (S) + Adper Scotchbond Multi-Purpose (SBM); 10HF/S/SB: 10HF + S + Single Bond Universal (SB); 10HF/SBM; 10HF/SB; S/SBM and S/SB. Two 1-mm-long plastic tubes were placed on the specimens, filled with RelyX ARC resin cement and cured for 20 s per tube. The plastic tube was removed, and the microshear bond strength was tested. Data were submitted to analysis of variance and Tukey's tests (α=0.05). Fractured specimens were observed under optical microscopy. For both adhesives, the bond strengths (MPa) of groups treated with acid-etching and silane (10HF/S/SB: 24.82, 10HF/S/SBM: 24.90) were higher (p<0.001) than those of groups treated with acid-etching (10HF/SB: 16.47, 10HF/SBM: 19.94) only or only silane (S/SB: 18.42, S/SBM: 13.24). All groups showed a predominance of failure adhesive. The silanization should be a clinical step in cementing ceramic structures reinforced by lithium disilicate, even with the application of universal adhesive that contains silane in its formulation.

Resumo O objetivo neste estudo foi avaliar a resistência de união ao microcisalhamento de estruturas protéticas cerâmicas reforçadas por dissilicato de lítio cimentadas com cimento resinoso sob diferentes tratamentos de superfície e sistemas adesivos. Setenta e duas barras retangulares de dissilicato de lítio (6,5 mm de comprimento × 5 mm de largura × 1 mm de espessura) foram fabricadas, tratados com partículas de Al2O3 (50 μm) e dividido em seis grupos (n=12) dependendo dos pré-tratamentos de superfície. Os grupos foram como se segue: 10HF/S/SBM: condicionamento com ácido fluorídrico 10% durante 20 s (10HF) + silano (S) + Adper Scotchbond Multi-Purpose (SBM); 10HF/S/SB: 10HF + S + Single Bond Universal (SB); 10HF/SBM; 10HF/SB; S/SBM; e S/SB. Dois tubos plásticos cilíndricos de 1 mm de comprimento foram colocados sobre os espécimes, preenchidos com cimento RelyX ARC e fotoativado durante 20 s por tubo. Os tubos plásticos foram removidos e a resistência de união ao microcisalhamento foi testada. Os dados foram submetidos à análise de variância e ao teste de Tukey (α=0,05). Espécimes fraturados foram observados sob microscopia óptica. Para ambos os adesivos, a resistência de união (MPa) dos grupos tratados com condicionamento ácido e silano (10HF/S/SB: 24,82, 10HF/S/SBM: 24,90) foram superiores (p<0.001) aos grupos tratados com condicionamento ácido apenas (10HF/SB: 16,47, 10HF/SBM: 19,94) ou apenas silano (S/SB: 18,42, S/SBM: 13,24). Todos os grupos apresentaram uma predominância de falha adesiva. A silanização deve ser um passo clínico em cimentação de estruturas cerâmicas reforçadas por dissilicato de lítio, mesmo com a aplicação do adesivo universal que contém em sua formulação um silano.

Efeito da Temperatura de Evaporação do Solvente na Longevidade da Adesão de Adesivos Autocondicionantes à Dentina / Effect of Solvent Evaporation Temperature on Bonding Longevity of All-In-One Adhesives to Dentin

Avaliou-se a durabilidade da adesão de adesivos autocondicionantes à dentina após evaporação dos solventes com jato de ar frio e quente. Os sistemas adesivos Clearfil 3S Bond e OptiBond All-In-One foram aplicados em superfícies planas de dentina, a evaporação dos solventes feita com ar quente (60±2 o C) ou ar frio (20±2 o C), seguindo-se fotoativação (600mW/cm2 por 10 s) e restauração com compósito (3 x 2 mm). Após armazenagem em água destilada (24 horas / 37 o C), as amostras foram seccionadas para obtenção de paralelogramos de 0,8 mm2 para testar em tração (0,5mm/min) em 24 horas e 6 meses. Dois paralelogramos de cada grupo experimental foram preparados para observar a nanoinfiltração na interface com a dentina. Os valores médios da resistência adesiva (em MPa) de cada grupo foram tratados por Análise de Variância de três fatores e teste de Tukey (5%), sendo o dente a unidade experimental. Foi observada maior adesão após evaporação dos solventes com ar quente (p=0.000) no tempo de 24 horas de armazenagem (0.003). Não houve diferenças para o tipo de adesivo (p=0.343) e nem para a interação adesivo X tempo X temperatura de evaporação do solvente (p>0,05). Concluiu-se que a durabilidade da adesão foi influenciada pela temperatura de evaporação do jato de ar

To evaluate the bonding longevity of one-step self-etch adhesive systems to dentin, after solvent evaporation with warm or cold airstream. Clearfil 3S Bond and OptiBond All-In-One adhesives were applied on flat dentin surfaces, solvent evaporation was performed with a warm (60±2 o C) or cold air (20±2 o C), the surfaces were light cured (600mW/cm2 during 10 s), and blocks of compositeres min were built (3 x 2mm). After storage in distilled water (24-hour at 37 o C), the samples were sectioned into 0.8 mm2 sticks and tested in tensile (0.5 mm/min) at 24-hour and 6-month periods. Two sticks from each experimental group were prepared for nanoleakage observation of the bond interface. The mean bond strength values of experimental groups (in MPa) were subjected to a three- way Analysis of Variance and post-hoc Tukey´s test (5%), using tooth as the experimental unit. Higher bond strength was observed with warm air (p=0.000) for solvent evaporation, and 24 hour of water storage (0.003. No significant differences were observed for both the adhesive systems (p=0.343) and interactions.The bonding durability was influenced by the air temperature for solvent evaporation

Influence of 10% sodium ascorbate gel application time on composite bond strength to bleached enamel.

Objective To analyze bond strength to bleached enamel following application of 10% sodium ascorbate gel. Material and methods Forty third molars were allocated into five groups (n = 8): GP - unbleached specimens restored with composite resin; GN - specimens restored immediately after bleaching; and G15; G30 and G60 (test groups) - bleached specimens treated with 10% sodium ascorbate gel for 15, 30 and 60 min before restoration. The teeth were sectioned and the buccal and lingual faces were restored. After storage in distilled water (37 °C/24 h), sticks of ±0.8 mm2 were tested in tensile (0.5 mm/min). Fractures were observed and classified. Data (in MPa) were analyzed with one-way ANOVA and Tukey tests (α = 0.05). Results No differences were found among GP (26 ± 6.0), G15 (23 ± 7.3), G30 (25 ± 6.1) and G60 (25 ± 5.1), with GN (15 ± 5.5) showing the lowest bond strength (p < 0.0001). Conclusion The application of 10% sodium ascorbate gel for 15 min after bleaching with 37.5% hydrogen peroxide restored the bonding to enamel.

Correlation between antioxidant activity and bonding strength on bleached enamel.

Objective: This study used the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) method to evaluate the percentage of antioxidant activity (%AA) of green tea (GT) and sodium ascorbate (SA) gel in three concentrations (10%, 20% and 30%), and the influence of these concentrations on the microshear bond strength (µ-SBT) values of bleached enamel, using 10% carbamide peroxide (CP). Materials and methods: Eighty intact third molars were selected to perform the µ-SBT test, and were randomly divided into eight experimental groups: G1: positive control - no treatment; G2: negative control - bleached with CP; G3: PC +10% GT; G4: PC +20% GT; G5: PC +30% GT; G6: PC +10% SA; G7: PC +20% SA and G8: PC +30% SA. After applying the treatments, adhesive procedures were performed using Single Bond 2 and Filtek Z350XT. After 24 h, the samples were tested in a universal testing machine until fracture. The %AA was assessed in triplicate by DDPH method using a UV-VIS spectrophotometer. Results: In the µ-SBT, ANOVA revealed no significant difference between the antioxidants evaluated (p = .625), but did reveal significant effects of the concentrations studied (p = .007). A negative correlation was observed between µ-SBT and solution concentrations. The values of %AA were from 90.58 to 96.75. Conclusions: The reverse results occurred in µ-SBT values, only when the antioxidants were used in a 10% concentration and, %AA did not influence µ-SBT.

Efeito de um Agente Dessensibilizante na Rugosidade do Esmalte Após Clareamento / Effects of Desensitizing Agent on the Enamel Roughness after Bleaching

O objetivo deste estudo foi avaliar a rugosidade superficial do esmalte dental hígido, submetido ao tratamento clareador de consultório e posterior aplicação de um agente dessensibilizante. Para este estudo, foram utilizados 40 incisivos bovinos para a obtenção de 60 fragmentos de esmalte (4 x 4 x 3 mm). Os blocos de esmalte foram preparados para a determinação da rugosidade inicial. Em seguida, as amostras foram dividas em 4 grupos experimentais (n=8): G1 - Grupo controle ? sem tratamento clareador, G2 - Peróxido de Hidrogênio a 35%, G3 - Peróxido de Hidrogênio a 35% + Dessensibilizante, G4 ? Agente dessensibilizante. Foram realizadas 3 aplicações, 15 minutos cada, do gel clareador e em seguida, de acordo com os grupos experimentais foi aplicado o agente dessensibilizante por 10 minutos. No fim dos tratamentos as amostras foram novamente submetidas a leitura da rugosidade de superfície. Os dados foram tabulados e submetidos a ANOVA (2 fatores), considerando os fatores tratamento e tempo. Os valores médios de rugosidade (Ra) obtidos (desvio padrão) foram: G1 inicial 0,17 (0,09) e final 0,18 (0,09); G2 inicial 0,15 (0,06) e final 0,21 (0,06); G3 inicial 0,13 (0,07) e final 0,18 (0,04) e G4 inicial 0,14 (0,08) e final 0,16 (0,08). A análise estatística dos dados revelou que não houve diferença estatisticamente significante antes e após a aplicação do agente dessensibilizante e gel clareador. Desta forma, podemos concluir que o clareamento de consultório, utilizando peróxido de hidrogênio a 35%, e aplicação de um agente dessensibilizante não altera a rugosidade superficial do esmalte dental.

The clinical evaluation of restorations in anterior teeth becomes essential due to the current aesthetic and functional appreciation by patients with regard to the appearance of the smile and oral health maintenance. The aim of this study was to perform a clinical evaluation of direct The aim of this study was to evaluate the intact enamel surface submitted to office bleaching followed by desensitizing agent application. For this study, 40 bovine incisors were used to obtain 60 enamel blocks (4 x 4 x 3 mm). The enamel blocks were prepared to determine initial surface roughness. Then, the samples were divided into four experimental groups (n = 8): G1 ? control group, no bleaching; G2 ? 35% hydrogen peroxide; G3 ? 35% hydrogen peroxide + desensitizing agent; G4 - desensitizing agent. The bleaching agent was applied for three times, 15 min each application and then the desensitizing agent was applied for 10 minutes according to the experimental groups. After treatments, the samples were again subjected to analysis of surface roughness. Data were tabulated and analyzed by ANOVA (two-way), considering the factors: time and treatment. The mean values (standard deviation) of roughness (Ra) were: G1 initial 0.17 (0.09) and final 0.18 (0.09); G2 initial 0.15 (0.06) and final 0.21 (0.06); G3 initial 0.13 (0.07) and final 0.18 (0.04) e G4 initial 0.14 (0.08) and final 0.16 (0.08). Data analysisrevealed no significant difference before and after applications of bleaching agent and desensitizing gel. Thus, we can conclude that office bleaching using 35% hydrogen peroxide and desensitizing agent application does not alter the tooth enamel surface roughness.

Bonding durability of dental sealants to deciduous and permanent teeth

AIM: To evaluate the bonding durability of materials used as sealants on different dentitions. METHODS: Deciduous (D) and permanent (P) molars were divided into four groups (n=5) and sealed with Fluroshield (F) and OptiBond FL (FL). Blocks of composite resin were built, stored in distilled water (24 h/37 °C), sectioned into 0.8 mm2 and tested at tensile (0.5 mm/min) after 24 h and 6 months. The fractures were observed and classified into adhesive, cohesive or mixed types. The data were analyzed using repeated measures ANOVA and Tukey test (α=5%), with tooth as the experimental unit. RESULTS: There were differences for dentition (p=0.0097), dental sealant (p=0.0019) and time (p=0.0001). At 24h the highest bond strength was observed for OptiBond FL on deciduous and permanent teeth, similar to Fluroshield at both dentitions. After 6 months the bond strength of OptiBond FL did not decrease in the permanent teeth, but decreased similar to Fluroshield in deciduous teeth, the bond strength of Fluroshield decreased similarly in both dentitions. CONCLUSIONS: The bond strength of dental sealants varied with the experimental conditions...

Comparison of frictional resistance between self-ligating and conventional brackets tied with elastomeric and metal ligature in orthodontic archwires.

OBJECTIVE: To compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire. MATERIAL AND METHODS: Abzil Kirium Capelozza (Pattern I) and Easy Clip (Roth prescription) incisor brackets were used. An elastomeric ligature or a 0.10-in ligating wire was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were assessed: 0.016-in NiTi wire, 0.016 x 0.021-in NiTi wire and 0.019 x 0.025-in steel wire. Ten observations were carried out for each bracket-archwire angulation combination. Brackets were mounted in a special appliance, positioned at 90 degrees in relation to the wire and tested in two angulations. Frictional test was performed in a Universal Testing Machine at 5 mm/min and 10 mm of displacement. The means (MPa) were submitted to ANOVA and Tukey's test set at 5% of significance. The surfaces of wires and brackets were observed at SEM. RESULTS: Steel-tied brackets (16.48 ± 8.31) showed higher means of frictional resistance than elastomeric-tied brackets (4.29 ± 2.16 ) and self-ligating brackets (1.66 ± 1.57) (P < 0.05), which also differed from each other (P < 0.05). As for the type of wire, 0.019 x 0.025-in steel wire (5.67 ± 3.97) showed lower means (P < 0.05) than 0.16-in NiTi wire (8.26 ± 10.92) and 0.016 x 0.021-in NiTi wire (8.51 ± 7.95), which did not differ from each other (P > 0.05). No statistical differences (P > 0.05) were found between zero (7.76 ± 8.46) and five-degree (7.19 ± 7.93) angulations. CONCLUSIONS: Friction was influenced not only by the type of bracket, but also by the ligating systems. Different morphological aspects were observed for the brackets and wires studied.

The influence of air temperature for solvent evaporation on bonding of self-etch adhesives to dentin.

OBJECTIVE: This study evaluated the effect of air temperature (warm or cold) for solvent evaporation on bonding and nanoleakage of self-etching adhesives to dentin. MATERIALS AND METHODS: The adhesives Clearfil 3S Bond [S3], OptiBond All-In-One [OB], Adper SE Plus [AD], and Silorane adhesive [SI] were applied on dentin surfaces, and a warm (60 ± 2°C) or cold air (20 ± 1°C) was applied and light-cured. After water storage (24 h), the teeth were sectioned into sticks (0.8 mm(2)) and tested in tensile. Then, they were immersed in a 50% solution of silver nitrate, photo-developed and the nanoleakage observed in a scanning electron microscope. The bond strength and nanoleakage pattern were analyzed by two-way analysis of variance and post hoc Tukey's test (α =0.05). RESULTS: Higher bond strength and lower silver nitrate uptake were observed for the adhesives under warm condition (P < 0.05). AD and SI showed better adhesive results than S3 and OB (P < 0.05). CONCLUSION: The use of a warm air was useful to improve the bonding and diminish the nanoleakage of adhesive systems to dentin.

Comparison of frictional resistance between self-ligating and conventional brackets tied with elastomeric and metal ligature in orthodontic archwires

OBJECTIVE: To compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire. MATERIAL AND METHODS : Abzil Kirium Capelozza (Pattern I) and Easy Clip (Roth prescription) incisor brackets were used. An elastomeric ligature or a ligating wire 0.10-in was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were assessed: 0.016-in NiTi wire, 0.016 x 0.021-in NiTi wire and 0.019 x 0.025-in steel wire. Ten observations were carried out for each bracket-archwire angulation combination. Brackets were mounted in a special appliance, positioned at 90 degrees in relation to the wire and tested in two angulations. Frictional test was performed in a Universal Testing Machine at 5 mm/min and 10 mm of displacement. The means (MPa) were submitted to ANOVA and Tukey's test set at 5% of significance. The surfaces of wires and brackets were observed at SEM. RESULTS: Steel-tied brackets (16.48 ± 8.31) showed higher means of frictional resistance than elastomeric-tied brackets (4.29 ± 2.16 ) and self-ligating brackets (1.66 ± 1.57) (P < 0.05), which also differed from each other (P < 0.05). As for the type of wire, 0.019 x 0.025-in steel wire (5.67 ± 3.97) showed lower means (P < 0.05) than 0.16-in NiTi wire (8.26 ± 10.92) and 0.016 x 0.021-in NiTi wire (8.51 ± 7.95), which did not differ from each other (P > 0.05). No statistical differences (P > 0.05) were found between zero (7.76 ± 8.46) and five-degree (7.19 ± 7.93) angulations. CONCLUSIONS: Friction was influenced not only by the type of bracket, but also by the ligating systems. Different morphological aspects were observed for the brackets and wires studied .

OBJETIVO: comparar a resistência ao atrito entre braquetes autoligáveis e braquetes convencionais, variando o tipo de fio. MÉTODOS: foram usados braquetes incisivos Abzil Kirium Capelozza e Easy Clip. Uma ligadura elastomérica ou um fio ligável de 0,010" foi usado para ligação do fio no braquete Abzil. Três tipos de ligas de fio ortodôntico foram avaliadas: fio de NiTi de 0,016"; fio de NiTi de 0,016" x 0,022"; e fio de aço de 0,019" x 0,025". Dez observações foram feitas para cada combinação "braquete-fio-inclinação". Os braquetes foram montados em um aparelho especial, posicionados a 90° em relação ao fio, e testados em duas inclinações. O teste de atrito foi realizado na máquina universal de ensaios, a 5mm/min e com 10mm de deslocamento. As médias (em MPa) foram submetidas aos testes ANOVA e de Tukey, a 5% de significância. As superfícies dos fios e dos braquetes foram observadas no MEV. RESULTADOS: o braquete com amarrilhos metálicos (16,48 ± 8,31MPa) apresentou médias mais altas que o braquete com ligaduras elastoméricas (4,29 ± 2,16MPa) e o braquete autoligável (1,66 ± 1,57) (p < 0,05), os quais também diferiram entre si (p < 0,05). Quanto ao tipo do fio, o fio de aço de 0,019" x 0,025" (5,67 ± 3,97MPa) apresentou médias mais baixas (p < 0,05) que os fios de NiTi de 0,016" (8,26 ± 10,92MPa) e de 0,016" x 0,022" (8,51 ± 7,95), os quais não diferiram entre si (p > 0,05). Nenhuma diferença estatística (p > 0,05) foi encontrada entre inclinações de zero (7,76 ± 8,46) e cinco (7,19 ± 7,93) graus. Concluão: o atrito foi influenciado pelo tipo de braquete e sistemas de ligaduras. Diferentes aspectos morfológicos foram observados para os braquetes e fios estudados. .

Effect of bleaching agents on the flexural strength of bovine dentin.

The aim of this study was to evaluate the effect of bleaching on the flexural strength of bovine dentin, using bleaching agents containing calcium (Whiteness HP Blue and Whiteness Class) and not containing calcium (Whiteness HP and Whiteness Perfect). Sixty bovine incisor tooth slices were obtained and divided into fve experimental groups (n = 12), such as G1, untreated control group; G2, Whiteness HP Max [35% hydrogen peroxide (HP)]; G3, Whiteness HP Blue (35% HP); G4, Whiteness Class (7.5% HP) and G5, Whiteness Perfect (22% carbamide peroxide). Samples were submitted to bleaching treatment according to the manufacturers' instructions. The control group remained in artificial saliva during bleaching. After bleaching, the enamel was removed and dentin specimens (7 mm length × 1.7 mm width × 0.5 mm thickness) were prepared. Samples were tested in a universal testing machine (EMIC). Data were analyzed by analysis variance (ANOVA) and Tukey's test. Differences between the groups were identified by ANOVA. The mean values (± standard deviation) for the experimental groups, such as (in MPa) G1 = 19.05 ± 2.68 a; G2 = 12.69 ± 4.52 b; G3 = 16.39 ± 3.74 ab; G4 = 14.90 ± 5.60 ab; and G5 = 12.71 ± 2.25 b. Groups with the same lowercase letter were significantly different from each other. The presence of calcium in bleaching agents appeared to influence the flexural strength of bovine dentin after bleaching treatment, for both office bleaching (35% HP) and home bleaching (7.5% HP).