Aim: The aim of this study was to explore the impact of oral health-related quality of life (OHRQoL) on the child’s family structure. Methods: A representative sample of 613 children from public preschools, in a city in southeastern Brazil, were enrolled in this cross-sectional study. The sample was determined through probabilistic sampling in two stages (preschools and children). The outcome variable (Early Childhood Oral Health Impact Scale [ECOHIS]) was multi-categorized in children and family. Independent individual variables were sex, race, family income, parents’/caregivers’ level of education, family income, dental caries, and malocclusion. Initially, individual analyses were performed, relating the study variables to the outcome variables, estimating the raw odds ratio with the respective confidence intervals of 95%. The variables with p < 0.20 in the individual analyses were tested in the multiple logistic regression models, and those with p < 0.10 remained in the model. Results: Impact on OHRQoL was reported by 40.9% of the children and 17% of their families. Children with low family income and caries experience had, respectively, 1.53 (95% CI: 1.00-2.32) (p = 0.0465) and 2.96 (95% CI: 1.81-4.84) (p < 0.0001) more chance of presenting negative impact on OHRQoL. Conclusions: The aspects that most affected the OHRQoL of child’s family structure were low income and dental caries experience.

Aim: The aim of this study was to verify the frictional force during sliding mechanics in orthodontic tooth movement, using conventional metal brackets of the active and passive self-ligating types with stainless steel and copper nickel titanium archwires. Methods: This experimental in vitro study was conducted with conventional metal (Morelli, Sorocaba, SP, Brazil) brackets, active self-ligated (SLI Morelli, Sorocaba, SP, Brazil) and passive self-ligated (SLP Morelli, Sorocaba, SP, Brazil), with slot 0.022 x 0.028 inches and Roth prescription.  The brackets were tested with rectangular section 0.019 x 0.025 inch copper nickel titanium and stainless steel archwires. For each type of bracket, 10 sets of plate/bracket/archwire segment (n=10) were fabricated. Non-parametric Kruskal Wallis and Dunn tests were used for comparison between types of brackets and Wilcoxon tests for comparison between types of archwires. Results: The results showed that the frictional force values were higher with copper nickel titanium than with stainless steel archwires (p<0.05). When copper nickel titanium archwires were used, the active self-ligating brackets showed higher frictional force values than the other types, followed by the conventional brackets.  Lower frictional force values were observed with passive self-ligating brackets. For stainless steel archwires, no difference was observed between conventional and active self-ligating brackets, the passive self-ligating type presented lower frictional force values than the others. Conclusion: It was concluded that the higher frictional force was observed when active self-ligating brackets were associated with copper nickel titanium archwires.  Lower frictional force was verified between passive self-ligating brackets combined with stainless steel archwires.

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Objective: The aim of this experimental in vitro study was to evaluate whether dental bleaching performed before orthodontic treatment change the shear bond strength (SBS) of monocrystalline and polycrystalline esthetic brackets. Methods: Sixty (60) bovine incisors teeth were used and randomly divided into the following six groups (n=10): SCP (without bleaching/polycrystalline brackets); SCM (without bleaching/monocrystalline brackets); 1CP (one bleaching session/polycrystalline brackets); 1CM (one bleaching session/monocrystalline brackets); 3CP (three bleaching sessions/polycrystalline brackets); and 3CM (three bleaching sessions/monocrystalline brackets). The brackets were bonded seven days after the bleaching sessions. The samples were submitted to the SBS test in a universal testing machine (Instron model 4411) at 1 mm/min crosshead speed. The two-way analysis of variance (ANOVA) and the Tukey tests were performed at a 5% level of significance. After the mechanical test, samples were evaluated to determine the adhesive remnant index (ARI). Results: The SBS values were significantly higher for the monocrystalline brackets, when compared with the polycrystalline type (p< 0.0001), and significantly higher with three bleaching sessions than without bleaching (p< 0.0436). The ARI showed predominance of failures between the bracket and resin for all the groups (score 3). Conclusion: Three dental bleaching sessions increased the SBS values. Monocrystalline brackets showed higher SBS values than the polycrystalline type.