Whitening Effect of Different Toothpastes on Bovine Dental Enamel: an in situ study.

The aim of this in situ study was to evaluate color change, surface roughness, gloss, and microhardness in tooth enamel submitted to whitening and remineralizing toothpastes. Fifteen healthy adults (REBEC - RBR-7p87yr) (with unstimulated salivary flow ≥ 1.5 ml for 5 minutes, pH=7) wore two intraoral devices containing four bovine dental fragments (6 x 6 x 2 mm). Participants were randomly assigned and instructed to toothbrush the devices with the tested toothpastes (30 days): CT: conventional; WT: whitening; WTP: whitening with peroxide, and RT: remineralizing toothpaste. A washout period of 7 days was established. Readouts of color, gloss, surface roughness, and microhardness were performed before and after brushing. The results demonstrated no color, gloss, and microhardness differences (p>0.5). The samples brushed with WTP (0.2(0.7) showed higher surface roughness (p=0.0493) than those with WT (-0.5(1.0). The toothpastes did not alter the properties of the dental enamel, except for the roughness. Toothpaste with an abrasive system based on sodium bicarbonate and silica, and that contains sodium carbonate peroxide increased the surface roughness of the enamel.

Whitening Effect of Different Toothpastes on Bovine Dental Enamel: an in situ study

Abstract The aim of this in situ study was to evaluate color change, surface roughness, gloss, and microhardness in tooth enamel submitted to whitening and remineralizing toothpastes. Fifteen healthy adults (REBEC - RBR-7p87yr) (with unstimulated salivary flow ≥ 1.5 ml for 5 minutes, pH=7) wore two intraoral devices containing four bovine dental fragments (6 x 6 x 2 mm). Participants were randomly assigned and instructed to toothbrush the devices with the tested toothpastes (30 days): CT: conventional; WT: whitening; WTP: whitening with peroxide, and RT: remineralizing toothpaste. A washout period of 7 days was established. Readouts of color, gloss, surface roughness, and microhardness were performed before and after brushing. The results demonstrated no color, gloss, and microhardness differences (p>0.5). The samples brushed with WTP (0.2(0.7) showed higher surface roughness (p=0.0493) than those with WT (-0.5(1.0). The toothpastes did not alter the properties of the dental enamel, except for the roughness. Toothpaste with an abrasive system based on sodium bicarbonate and silica, and that contains sodium carbonate peroxide increased the surface roughness of the enamel.

Resumo O objetivo deste estudo in situ foi avaliar a alteração de cor, rugosidade superficial, brilho e microdureza em esmalte dentário submetido a dentifrícios clareadores e remineralizantes. Quinze adultos saudáveis (REBEC - RBR-7p87yr) (com fluxo salivar não estimulado ≥ 1.5 mL por 5 minutos, pH = 7) usaram dois dispositivos intrabucais contendo quatro fragmentos dentários bovinos (6 x 6 x 2 mm). Os participantes foram aleatoriamente designados e instruídos a escovar os aparelhos com os dentifrícios testados (30 dias): CO: convencional; CL: clareador; CLP: clareador com peróxido e RE: remineralizante. Foi estabelecido um período de washout de 7 dias. Leituras de cor, brilho, rugosidade superficial e microdureza foram realizadas antes e após a escovação. Os resultados não demonstraram diferenças na cor, brilho e microdureza. As amostras escovadas com CLP apresentaram maior rugosidade superficial (p=0,0493) do que aquelas com CL. Os dentifrícios não alteraram as propriedades do esmalte dental, exceto a rugosidade. O dentifrício com sistema abrasivo à base de bicarbonato de sódio e sílica, e que contém peróxido de carbonato de sódio aumentou a rugosidade de superfície do esmalte.

The effect of phytosphingosine associated with tooth brushing on color change, surface roughness, and microhardness of dental enamel - an in vitro and in situ study.

OBJECTIVE: This study evaluated the in vitro and in situ effects of phytosphingosine (PHS) associated with tooth brushing on color stability, surface roughness, and microhardness of dental enamel. METHODS: Sixty-four specimens of bovine teeth (6 × 6 × 2 mm) were separated into 8 groups (n = 8): S + TB: PHS (spray) + tooth brushing; TB + S: tooth brushing + PHS (spray); I + TB: PHS (immersion) + tooth brushing; TB + I: tooth brushing + PHS (immersion); TB: tooth brushing; S: PHS spray; I: immersion in PHS solution, and Saliva: immersion in saliva. Tooth brushing simulation (Mavtec, Brazil) was performed (356 rpm on 3.8 cm area by the toothbrush - Soft Tek) for 1, 7, 15, and 30 days. PHS remained in contact with specimens for 15 min. The specimens were evaluated before and after tooth brushing for color alteration (Easy Shade, VITA), and surface roughness (Model SJ-201P Mitutoyo), and Knoop microhardness (HMV-2, Shimadzu Corporation). For the in situ analyses, 8 participants were recruited and received an intraoral device with 6 fragments of bovine enamel (6 × 6 × 2 mm). The properties evaluated were the same as those of the in vitro study. Participants were randomized following best results of in vitro tested protocols, for 15 days: TB, TB + S, I + TB. Data obtained by in vitro (two-way ANOVA, Tukey, p < .05) and in situ (one-way ANOVA, Tukey, p < .05) studies were analyzed. RESULTS: The in vitro study showed that greater color change was found after 30 days. The greatest differences in surface roughness occurred between the initial value and after 1 day. Regarding microhardness, the highest values occurred after 15 and 30 days, which showed similar results. The in situ study showed greater color changes for the TB and I + TB, and greater surface roughness changes for TB as well as a similar increase in microhardness for the PHS protocols, which were higher than TB. CONCLUSIONS: Phytosphingosine leads to an increase in performance regarding color stability, surface roughness, and microhardness when applied. In general, the application of PHS after brushing showed a positive impact on its performance. CLINICAL RELEVANCE: Phytosphingosine proved to be interesting for compound prevention formulations in the dentistry field.

Effect of Incorporation of Bioactive Glass-Ceramic into Self-etch Adhesives.

PURPOSE: This study evaluated the effect of incorporating different concentrations of biosilicate in an experimental self-etch adhesive (SE). MATERIALS AND METHODS: Biosilicate microparticles (0, 2, 5, and 10 wt%) were incorporated into the primer, and degree of conversion (DC) and wettability were tested (one-way ANOVA, Tukey's test, p < 0.05). The two best concentrations were selected (2% and 5%) for µTBS evaluation. Sound human molars (n=20) were sectioned into quarters and randomly assigned to 4 experimental groups: 1. experimental SE + 0% biosilicate (Exp0%; negative control); 2. experimental SE + 2% biosilicate (Exp2%); 3. experimental SE + 5% biosilicate (Exp5%); 4. AdheSE (Ivoclar Vivadent, positive control). After adhesive application, Filtek Z350 (3M Oral Care) composite was built up incrementally to 5 mm. Each quarter tooth was sectioned into sticks (0.9 mm2) and stored in distilled water (37°C) for 24 h, 6 months, or 1 year. After storage, sticks were submitted to µTBS (0.75 mm/min). The Ca:P ratio was analyzed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Data were analyzed using two-way ANOVA with Bonferroni's correction, with statistical siginificance set at p < 0.05. Fracture patterns were observed under a digital microscope and adhesive interfaces with transmission electron microscopy (TEM). RESULTS: Exp2% presented the highest DC (p < 0.05), Exp5% exhibited the lowest µTBS (p < 0.05), and adhesive failures were predominant in all groups. TEM suggested remineralized areas in Exp2% and to a lesser degree in Exp5%. Exp2% and Exp5% showed a higher Ca:P ratio after aging (p < 0.05). CONCLUSION: The incorporation of biosilicate microparticles can improve the properties of self-etch adhesives. It increased the DC of the experimental adhesive as well as mineral deposition. However, the adhesive properties are concentration dependent, as a higher concentration of microparticles can adversely affect the mechanical properties of an adhesive.

Over-the-counter bleaching agents can help with tooth whitening maintenance.

OBJECTIVE: This study evaluated the influence of over-the-counter agents on the maintenance of color and microhardness of the enamel after home bleaching protocol. MATERIALS AND METHODS: Specimens of bovine teeth (6 × 6 × 2 mm) were prepared, and color (Easyshade, VITA) and microhardness (HMV-2, Shimadzu) readings were performed. All the specimens were bleached using 22% carbamide peroxide (22%CP), except for the control group, and then separated into seven groups (n = 10) according to the interaction of toothpaste (whitening, conventional, and whitening with peroxide) and mouth rinse (whitening and conventional). The study simulated 1 year of toothbrushing (Pepsodent, MAVTEC) and mouth rinse by immersion. After that, final color and microhardness measurements were performed. Data were analyzed by one-way ANOVA, Tukey's test (P < .05). RESULTS: The group submitted to 22%CP + whitening toothpaste + whitening mouth rinse showed higher color maintenance (P < .05) than the control group. The perception of whitening of teeth (ΔWID ) was higher than the color change (ΔE00 ). There was a decrease in microhardness after treatment with 22%CP + conventional toothpaste + whitening mouth rinse. CONCLUSIONS: Over-the-counter products can help with the maintenance of tooth whitening after bleaching with carbamide peroxide; however, special attention should be given since the association of products can also reduce the microhardness of the dental enamel. CLINICAL SIGNIFICANCE: The association between whitening toothpastes and mouth rinses might be beneficial for maintaining color during 1 year after bleaching treatment.

Effect of natural primer associated to bioactive glass-ceramic on adhesive/dentin interface.

OBJECTIVES: This study evaluated the effect of propolis associated with Biosilicate on the bond strength (BS) and gelatinolytic activity at the adhesive/dentin interface. METHODS: Occlusal cavities were prepared in 320 human molars. Half of them were submitted to cariogenic challenge. All the teeth were separated into eight groups (n = 20): Control - Adhesive System (Single Bond Universal, 3 MESPE); CHX - 0.12 % Chlorhexidine; Bio - 10 % Biosilicate; P16 - Propolis with low levels of polyphenols; P45 - Propolis with high levels of polyphenols; CHX Bio - CHX + Bio; P16 Bio - P16+Bio; P45 Bio - P45+Bio. The adhesive was applied (self-etch mode) after treatments. Restorations (Filtek Z350, 3 MESPE) were performed and samples sectioned into sticks, separated and stored in distilled water at 37 °C for 24 h, 6 months and 1 year. Microtensile BS (0.5 mm/min) was tested and analyzed (2-way ANOVA, Bonferroni's Test, p < .05 and Weibull analysis). Fracture patterns (VH-M100, Keyence) and adhesive interfaces (SEM, EVO-MA10, ZEISS and TEM, JEM-1010, JEOL) were observed; and biodegradation and in situ zymography performed. RESULTS: P16 presented the highest BS values on sound dentin after 6 months. In caries-affected dentin (CAD), the association of treatments promoted the highest BS after 24 h. Sound dentin obtained significantly higher Weibull modulus than CAD. SEM displayed resin tags in P16, P45 and association of treatments. TEM showed good interaction between adhesive and dentin. According to the in situ zymography and biodegradation assay all natural primers reduced the gelatinolytic activity. P45 presented the lowest biodegradation and enzymatic activity. CONCLUSIONS: Propolis and the association of treatments promoted the highest bond strength results and preserved the dentin. All the experimental groups exhibited low gelatinolytic activity. CLINICAL SIGNIFICANCE: Propolis and the association of treatments with Biosilicate could preserve the dentin substrate and improve the longevity of composite restorations.

Effect of thermo-mechanical cycling and chlorhexidine on the bond strength of universal adhesive system to dentin.

OBJECTIVES: This study evaluated the influence of thermo-mechanical cycling (TMC) on the bond strength (BS) of a universal adhesive system (UAS - Adper Single Bond Universal, 3M ESPE) to dentin treated or not with 0.2% chlorhexidine (CHX). METHODS: Eighty human molars were flattened until reach the dentin and separated into 4 groups according to the bonding protocol: ENR Group: 37% phosphoric acid + 3-step etch-and-rinse adhesive system (ENR); UAS Group: UAS in self-etch mode; ENR + CHX Group: 37% phosphoric acid + CHX + ENR; UAS + CHX Group: CHX + UAS in self-etch mode. After treatments, teeth were restored (Filtek Z350, 3M ESPE). Samples (n = 10) were submitted to aging process: stored in distilled water at 37°C/30 days or TMC (ERIOS - 98N/1.6Hz + thermal cycling 5/37/55 °C - 1,200,000 cycles). Specimens were sectioned into sticks (1.0 mm2) and submitted to the microtensile test (Mechanical Test Machine - 0.5 mm/min). Fracture patterns and hybrid layer integrity were analyzed under Stereomicroscope and Scanning Electron Microscopy (SEM). RESULTS: The BS results (3-way ANOVA, Bonferroni's test, α = 5%) showed that groups treated with CHX presented higher BS values than control groups; significant in all cases (p < .05), except for ENR submitted to TMC (p > .05). When CHX was applied and samples were cycled, UAS revealed higher BS (p < .05) than ENR. After TMC, cohesive fractures increased for UAS, regardless of CHX application. SEM analysis demonstrated different hybridization patterns for the adhesive systems tested. CONCLUSION: The performance of the universal adhesive system used in self-etch mode was better than that of the 3-step etch-and-rinse adhesive system. CLINICAL SIGNIFICANCE: Universal adhesive systems have been developed in order to simplify the dentin hybridization protocol. It is important to determine the longevity of the adhesive interface using these bonding materials after chewing.

Color stability and surface roughness of composite resins submitted to brushing with bleaching toothpastes: An in situ study.

OBJECTIVE: To evaluate, in situ, the color stability (CS) and surface roughness (SR) of composite resins after toothbrushing with whitening toothpaste. MATERIALS AND METHODS: Specimens (6 × 2 mm/) of composite resin (Tetric N-Ceram, Z250 and Z350) were randomly fixed on thirty participants' upper molars (buccal surface). For an initial standardization (7 days), participants used a soft toothbrush and nonwhitening toothpaste (SDB - Sorrisos Dentes Brancos). Initial CS (Easyshade) and SR (Surfcorder RS) measurements were performed. For SR, impressions of specimens were taken (Express, 3 M ESPE) to produce replicas in polyurethane resin (Axon F16, Abcol). Participants were randomly separated into three groups (n = 10) regarding used toothpaste (SDB; Close up White Now - CWN; Colgate Luminous White - CLW). After 90 days, CS and SR measurements were obtained, and data were analyzed (2-way ANOVA, repeated measures, Bonferroni, P < .05). RESULTS: Z250 showed higher (P < .05) color change than Z350. Tetric N-Ceram presented an intermediary value for ΔE, however, it also demonstrated higher SR (P < .05) after brushing with CLW, compared with SDB and CWN. CONCLUSIONS: The SR change of composite resin after toothbrushing with a whitening toothpaste is material dependent, but the toothpaste abrasiveness does not change the CS. CLINICAL SIGNIFICANCE: Whitening toothpaste do not change the color stability of composites; however, it can alter the restorative composite surface roughness.

Effectiveness of over-the-counter tooth-whitening strips and toothbrushing for stain removal / Eficácia da utilização de tiras de clareamento dental e da escovação na remoção de manchas dentais

Objective: The present study compared the effectiveness of over-the-counter tooth-whitening strips and too-thbrushing for stain removal. Materials and method: Forty bovine teeth were subjected to initial color re-adings and divided into two groups: 20 teeth were stained with grape juice for seven days and 20 did not receive any treatment (control). Each group was subdivided into two groups (n=10) according to treatment: whitening strips twice/day (30 minutes/7 days) and mechanical brushing with toothpaste (one year). After the treatments, final color readings were taken and color stability (ΔEab), coordinates (ΔL, Δa, Δb), and whitening index (WID) were calculated and analyzed statistically (two-way ANOVA, Bonferroni α=0.05). Results: Statis-tical differences were found for ΔEab and all coordinates between the Control and Stained groups, with major changes in the Stained groups for both treatments. In the Control group, whitening strips produced greater changes in Δb (p <0.05), indicating decrease of yellowness. For the Stained group, whitening strips produced greater changes in Δa (p <0.05), indicating redness reduction. Conclusion: Both treatments were effective for removing stains, and whitening strips were more efficient and effective for changing the color of teeth without previous staining. (AU)

Objetivo: o presente estudo comparou a eficácia das tiras de clareamento dentário e da escovação na remoção de manchas. Materiais e método: quarenta dentes bovinos foram submetidos à lei-tura inicial de cor e divididos em dois grupos: 20 manchados com suco de uva por 7 dias e 20 não receberam tratamento (controle). Cada grupo foi subdividido em 2 grupos (n=10) de acordo com o tratamento: tiras de clareamento 2 vezes/dia (30 minutos/7 dias) e escovação mecânica com cre-me dental (1 ano). Após os tratamentos, leituras finais de cor foram realizadas. Então, a estabili-dade de cor (ΔEab), as coordenadas (ΔL, Δa, Δb) e o índice de clareamento (WID) foram calculados e analisados estatisticamente (two-way ANOVA, Bonferroni α=0,05). Resultados: diferenças es-tatísticas foram encontradas em ΔEab e todas as coordenadas entre os grupos controle e mancha-dos, com maior alteração no grupo manchado, independente do tratamento. No grupo controle, o clareamento produziu maior alteração em Δb (p <0,05), indicando redução do croma amarelo. Nos dentes manchados, ocorreu maior alteração em Δa nos dentes clareados (p <0,05), indicando diminuição do croma vermelho. Conclusão: am-bos os tratamentos foram eficazes na remoção de manchas e o clareamento dentário mostrou-se um método mais eficiente e efetivo para alteração de cor de dentes que não haviam sido submetidos à pigmentação prévia. (AU)