Effect of Home-Use and In-Office Bleaching Agents Containing Hydrogen Peroxide Associated with Amorphous Calcium Phosphate on Enamel Microhardness and Surface Roughness

Statement of the Problem: The effects of amorphous calcium phosphate (ACP)-containing bleaching agents on enamel surface have not been clarified yet. Purpose: The study aims to evaluate the effects of different bleaching agents, either associated with ACP, or not, on enamel Knoop microhardness (KHN) and surface roughness (SR). Materials and Methods: The home-use hydrogen peroxide (HP) bleaching agents PolaDay 7.5% (HP7.5; SDI Limited, Bayswater, Victoria, Australia), PolaDay 9.5% (HP9.5; SDI Limited); DayWhite ACP-7.5% (ACP7.5; Discus Dental, Culver City, CA, USA) and DayWhite ACP 9.5% (ACP9.5; Discus Dental), and the in-office agents PolaOffice 35% (HP35; SDI Limited) and Opalescence XtraBoost 38% (HP38; Ultradent Products, South Jordan, UT, USA) were applied to polished enamel slabs (N = 10) for 30 minutes/day for 21 consecutive days (home-use) or in one session a week, for 3 weeks (in-office). KHN and SR were tested before (baseline), during (7, 14, 21 days), and after (7 and 14 days in artificial saliva) the bleaching treatment. Results: KHN evaluation revealed no significant difference among bleaching agents (p > 0.05); however, there was a significant decrease during bleaching treatment (p 0.05). SR was not altered during and after treatment, with the exception of PH38, which showed an increase in SR during bleaching treatment and a recovery after treatment. The ACP7.5 showed a trend to decreasing SR values during the bleaching treatment, but this decrease was only significant when associated with 14 days of immersion in artificial saliva, when the enamel was less rough than at baseline. Conclusions: Bleaching agents caused a decrease in enamel KHN, but values were recovered after treatment, showing the importance of saliva in recovering mineral content. SR was altered during or after treatment, depending on HP concentration/association with ACP. The beneficial effects of adding ACP to bleaching formulas on SR may be restricted to lower HP concentrations in association with the remineralizing effect of saliva. CLINICAL SIGNIFICANCE No beneficial effects of adding ACP to bleaching formulas on enamel microhardness were observed, but these observations may be attributable to the lower hydrogen peroxide concentrations in association with the remineralizing effect of saliva, when considering the enamel roughness.23315816

Surface roughness evaluation and shade changes of a nanofilled resin composite after bleaching and immersion in staining solutions

Purpose: To investigate the effect of bleaching and staining solutions on roughness and shade changes in a nanofilled resin composite [Filtek Supreme (FS)]. Methods: FS specimens (n= 135) were light cured and separated into groups (n=45) that were bleached with 10% carbamide peroxide (CP) agent or 16% or 35% hydrogen peroxide (HP). In the first two groups the bleaching gel was used for 4 hours a day, during 14 days, and for the third group in three sessions of 45 minutes. Each group was subdivided (n=15) and immersed in coffee, red wine or distilled water for 3 hours a day during 40 days. The roughness values (Ra) and shade (parameter CIELab) were evaluated at baseline, after bleaching and after staining. The data was analyzed by ANOVA and Tukey test or Kruskal Wallis. Results: The effects on specimens varied depending on the bleaching product and staining solution. FS after bleaching and after staining presented higher roughness. In the evaluation of shade changes after bleaching, it was observed that resin color changed and that 35% hydrogen peroxide bleached the resin more than the others. After staining in three solutions, all specimens changed color and wine showed the higher staining capacity. (Am J Dent 2011;24:245-249).24424524

Tensile bond strength of indirect composites luted with three new self-adhesive resin cements to dentin

OBJECTIVE: The aims of this study were to evaluate the tensile bond strengths between indirect composites and dentin of 3 recently developed self-adhesive resin cements and to determine mode of failure by SEM. MATERIAL AND METHODS: Exposed dentin surfaces of 70 mandibular third molars were used. Teeth were randomly divided into 7 groups: Group 1 (control group): direct composite resin restoration (Alert) with etch-and-rinse adhesive system (Bond 1 primer/adhesive), Group 2: indirect composite restoration (Estenia) luted with a resin cement (Cement-It) combined with the same etch-and-rinse adhesive, Group 3: direct composite resin restoration with self-etch adhesive system (Nano-Bond), Group 4: indirect composite restoration luted with the resin cement combined with the same self-etch adhesive, Groups 5-7: indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem, Maxcem, and Embrace WetBond, respectively) onto the non-pretreated dentin surfaces. Tensile bond strengths of groups were tested with a universal testing machine at a constant speed of 1 mm/min using a 50 kgf load cell. Results were statistically analyzed by the Student's t-test. The failure modes of all groups were also evaluated. RESULTS: The indirect composite restorations luted with the self-adhesive resin cements (groups 5-7) showed better results compared to the other groups (p0.05). The surfaces of all debonded specimens showed evidence of both adhesive and cohesive failure. CONCLUSION: The new universal self-adhesive resins may be considered an alternative for luting indirect composite restorations onto non-pretreated dentin surfaces

Periodontal outcomes and social, racial and gender inequalities in Brazil: a systematic review of the literature between 1999 and 2008 Condições periodontais e desigualdades sociais, raciais e de gênero no Brasil: revisão sistemática da literatura do período de 1999 a 2008

The objective of this study was to review the Brazilian epidemiologic literature on periodontal outcomes and socio-demographic factors, assessing bibliographic and methodological characteristics of this scientific production, as well as the consistency and statistical significance of the examined associations. A systematic review was carried out in six bibliographic sources. The review was limited to the period between 1999 and 2008, without any other type of restriction. Among the 410 papers identified, 29 were included in the review. An increasing number of articles, specifically in the last four years of study, was observed. However, there is a concentration of studies in the South and Southeast regions of Brazil, and many of them are not closely connected to theoretical formulations in the field. In spite of these shortcomings, the review findings corroborate the idea that poor socioeconomic conditions are associated with periodontal outcomes, as demonstrated primarily by income and schooling indicators.<br>O objetivo deste trabalho foi revisar a literatura epidemiológica brasileira sobre condições periodontais e aspectos sociodemográficos, avaliando características bibliográficas e metodológicas dessa produção, bem como a consistência e a significância estatística das associações examinadas. Foi conduzida uma revisão sistemática, por meio de consulta eletrônica, a seis fontes bibliográficas. A revisão foi restrita ao período de 1999 a 2008, sem a imposição de quaisquer outros limites de pesquisa. Entre os 410 artigos identificados, 29 foram incluídos na revisão. Observa-se crescimento da produção, especialmente no último quadriênio. Entretanto, há uma concentração dos estudos nas regiões Sul e Sudeste do país, e os trabalhos não se apoiam explicitamente em elaborações teóricas pertinentes ao tema. Apesar dessas limitações, os resultados dessa revisão sugerem que há uma relação inversa entre indicadores socioeconômicos e desfechos periodontais, demonstrada especialmente por indicadores de renda e escolaridade