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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

Aim: The objective of this study was to measure and compare the in vitro performance of active and passive self-ligating brackets in orthodontic rotation by means of an electromagnetic field simulation. Methods: The study sample consisted of 32 mandibular right central incisor brackets (n=8), slot 0.022", that were divided into the following groups: 1) BioQuick® (Forestadent, Pforzheim, Germany) active brackets; 2) In-Ovation®R (Dentsply-GAC, Central Islip, New York, USA) active brackets; 3) Damon-Q® (Ormco, Orange, California, USA) passive brackets, and 4) Smartclip® (3M, Monrovia, California, USA) passive brackets. The orthodontic wire used was CuNiTi round section 0.016", thermoactivated at 35o C (ORMCO-Orthodontics Glendora, California, USA). The experiment was performed in a simulator machine, composed of two fixed lateral axes and a movable central axis, which simulated the dental rotation. Qualitative analysis (n = 4) was performed using SEM. After the descriptive and exploratory analysis, the yield and grade data were submitted to one-way analysis of variance (ANOVA) followed by the Tukey test, considering the level of significance of 5%. Results: In-Ovation®R brackets showed significantly higher yield than BioQuick® and Damon-Q®. Damon-Q® brackets presented a significantly lower mean value than In-Ovation R and Smartclip®. BioQuick® did not differ significantly from Damon-Q® and Smartclip®. In-Ovation®R did not differ significantly from Smartclip®. Conclusion: In the present study, it was observed that there is a difference in rotational control in the different self-ligating brackets tested being the best rotational control was the In-Ovation R® group (active), followed in descending order by the groups Smartclip® (passive), Bioquick® (active) and Damon Q® (passive).

Aim: The study evaluated, using histomorphometry, the percentage of hyaline area in periodontal ligament (PDL) and root resorption in orthodontic tooth movement (OTM). Methods: Ten rats were divided into two groups. G3 Group (n=5), with 3 days of OTM and G7 Group (n=5), with 7 days of OTM. A Control Group (n=5) consisted of contralateral teeth of each animal, which were not moved. Maxillary left first molar was moved, using stainless steel spring connected to the incisors with 40g force. Microscopic analysis was done in transversal sections of the mesiovestibular (MV) and distovestibular (DV) roots in the cervical level. Results: There was a PDL hyaline area in the DV root of 6.2% in G3 and 1.8% in G7. The root resorption area in G7 was 0.9%. On MV root and Control Group were not found occurrences of hyaline areas in PDL and no root resorption. Conclusions: Based on the results obtained, it might be concluded that smaller roots showed higher frequency of hyaline areas and root resorption.

Aim: To evaluate signs and symptoms of temporomandibular joint disorder and satisfaction in patients before and after orthognathic surgery. Methods: The sample consisted of 15 patients aged between 19 and 47 years old, indicated for orthodontic-surgical treatment. All patients answered na anamnesis questionnaire based on Helkimo Anamnestic Index to evaluate subjective symptoms and underwent a clinical evaluation based on Helkimo Disfunction Index, applied at three time points: before (T0), three (T1) and six months (T2) after surgery. Statistical models used were χ2 test (Chi-square), Tukey test, confidence interval and analysis of variance (ANOVA). Results: Statistical analysis revealed no significant difference in the incidence of joint sounds, maximum mouth opening, deviation of mouth opening and pain in the TMJ region (p>0.05). No patient presented worsening of the symptomatology. As regards muscular pain, there was a statistically significant improvement with time (p

Aim: This study evaluated the surface roughness (Ra) and the topography (scanning electron microscopy) of the dental enamel after use of different methods for removal of residual resin after debonding of orthodontic brackets. Methods: Nine roughness measurements in three directions were made on enamel surface of 60 human premolars before bracket bonding (Ra initial). Ceramic brackets were bonded with Transbond XT and stored for 24 h/37°C before debonding with pliers. The specimens were divided in five groups according to the method used for removal of residual resin: control (C); carbide bur at slow-speed (CL); carbide bur at high speed (CH); Shofu tip at low speed (SB); Shofu tip at high speed (HB); debonding pliers (ZP). Nine final surface roughness measurements (Ra final) were made and one specimen of each group was observed by SEM. The data were analyzed statistically by ANOVA, Tukey’s test and paired t test (p

Aim: The present study aimed to assess, in vitro, the effect of chlorhexidine on the potentiation of polycrystalline ceramic bracket staining. Methods: Seventy-two polycrystalline ceramic brackets of upper right central incisors were divided into six groups (n=12) according to immersion solution. The groups were G1 - distilled water (control); G2 - chlorhexidine; G3 - coffee; G4 - red wine; G5 - chlorhexidine associated with coffee; and G6 - chlorhexidine associated with red wine. The samples were analyzed by means of a spectrophotometer according to the CIEL*a*b* system, and color change (ΔE*) was calculated. The readings were performed at the following times: T0 - After package removal and T1 - After staining. The data were analyzed by Kruskal Wallis and t tests (p

Aim: to evaluate the synergic impact of muscular TMD and malocclusion on quality of life, masticatory capacity and emotional features of young adults. Methods: this cross-sectional study comprised 4 groups (n= 15): G1, individuals without TMD or malocclusion; G2, with TMD and malocclusion; G3, with TMD and without malocclusion, and G4, without TMD and with malocclusion. Muscular TMD was diagnosed by RCD/TMD. Data included quality of life (OHIP-14), masticatory capacity test (X50), emotional stress (PSS-14), depression (MDI), pain intensity and salivary cortisol. Comparative statistical analysis included One-way ANOVA and Tukey post hoc test (X50, stress and cortisol) and GENMOD followed by Wald test (OHIP-14 and pain data). Fisher's and Pearson's association analysis were carried out. Results: Comorbidity of muscular TMD and malocclusion leads to significant lower masticatory capacity (p

Aim: This in vitro study investigated the effect of the application of an adhesive, silane and thermal cycling (TC) on the shear bond strength (SBS) of ceramic brackets to feldspathic ceramic. Methods: 16 cylinders of feldspathic ceramic were etched with hydrofluoric acid and divided into four groups (n=4): G1 - silane, without TC; G2 – silane, with TC; G3 - adhesive, without TC; G4 - adhesive, with TC. One layer of silane was applied on the surface of cylinders in G1 and G2 e one layer of photo-activated adhesive Single Bond Universal was used in G3 and G4. Ceramic brackets were bonded using Transbond XT. The SBS data were subjected to two-way ANOVA and Tukey’s post hoc test (α=0.05). The Adhesive Remnant Index (ARI) was evaluated at 40× magnification. Results: Silane was more effective than adhesive on the SBS of the brackets to ceramic (p

Aim: The purpose in this study was to evaluate the degradation force of conventional synthetic orthodontic elastics and synthetic orthodontic elastics with memory properties. Methods: Specimens of each material (Plastic chain, Memory chain and Closed spring NiTi) were stretched and adapted to the test specimens composed of resin plates and orthodontic wires, simulating retraction units. Degradation force was verified in an Instron universal test machine at the following intervals: 1, 2, 18, 24, 48 h; 7, 14, 21, and 28 days. Data (gF) were analyzed statistically using Friedman and Kruskal-Wallis tests at 5% significance level. Results: It was observed a significant force reduction of Plastic chain and Memory chain after 2 h (p