Background:The purpose of the present study was to evaluate the influence of asthma on the degree of apical root resorption in patients treated orthodontically. Methods: Sample comprised 683 patients treated orthodontically; 240 with asthma and 443 who did not present any kind of respiratory allergy or asthma. The Levander and Malmgren score was used for the evaluation of the degree of root resorption. This evaluation was performed in the initial and final periapical radiographs of the maxillary and mandibular incisors of all patients in the sample. Then, the sample was divided as follows: Group 1: 614 patients presenting mild or no root resorption with scores 0, 1 and 2, with mean initial age of 14.37 years, final age of 16.44 years and treatment time of 2.07 years; group 2: 69 patients who had moderate to severe root resorption with scores 3 and 4, with mean initial age of 15.09 years, final age of 17.81 years and treatment time of 2.72 years. Results: The results revealed that asthma was not a statistically significant factor for severe root resorption. The group with severe root resorption showed higher initial and final age, and longer treatment time than the group with mild root resorption. In addition, performing extractions is a risk factor for the occurrence of severe root resorption. Conclusions: Asthma is not a risk factor for the occurrence of severe root resorption after orthodontic treatment.

BackgroundThe objective of this work is to test the null hypothesis that there is no difference in the torque expression among different esthetic brackets.Material and MethodsFive ceramic self-ligating brackets (In-Ovation C – GAC, Damon Clear–Ormco, QuicKlear-Forestadent, Click-It -TP Orthodontics, Clarity SL-3M Unitek) and 4 ceramic conventional brackets (Inspire Ice–Ormco, InVu Ceramic-TP Orthodontics, Ceramic Roth–Morelli, Clarity Metal-Reinforced Ceramic Bracket-3M Unitek) were selected. Metallic Damon MX self-ligating bracket (Ormco) was used as control. Third-order moments were measured at 12º, 24º and 36º using an archwire torsion device associated with a Universal Testing Machine (EMIC DL2000), with 0.019x0.025-inch stainless steel wire. Anova followed by Tukey tests were used for intergroup comparisons.ResultsIn all tested angulations the Damon Clear bracket presented the highest torque expression, followed by Clarity, Clarity SL and Damon Mx brackets, with the worst torque expression shown by the InVu Ceramic bracket. The InVu Ceramic demonstrated the largest while the Damon Clear brackets demonstrated the smallest slot height and clearance.ConclusionsThe null hypothesis was rejected since torque expression was different among the esthetic brackets evaluated. It was also concluded that the slot height is directly related to torque expression. Key words:Torque, orthodontic brackets, orthodontic appliances, incisor, ceramics.