Tomographic evaluation of buccal bone in different skeletal patterns and incisors inclination.

OBJECTIVE: The aim of this study was to correlate the absence of BB with skeletal patterns and incisor inclination using cone-beam computed tomography (CBCT). METHODS: The sample comprised CBCT images of 45 patients undergoing orthodontic treatment. BB was classified in each third of the anterior teeth as critical, slender, regular, and thick. The skeletal pattern was determined by the ANB (A point, nasion, B point) angle and the incisor inclination using the 1.NA and 1.NB measurements and the interincisal angle (1:1). RESULTS: In both analyses, the skeletal pattern of class II revealed better BB in the cervical and middle thirds than classes I and III. A higher proportion of critical BB was found in the middle thirds, and the apical third presented the best regular and thick BB conditions, mainly class I. Less BB was observed in middle and apical thirds in the upper incisors and in cervical thirds in lower incisors, mostly when they were more upright. CONCLUSIONS: Knowledge of alveolar bone height and thickness can alter the treatment plan in orthodontics. During orthodontic treatment, more attention should be paid to the lower incisors and vertical teeth because of poor BB conditions, especially in class III skeletal patterns.

Evaluation of the susceptibility to pigmentation of orthodontic esthetic elastomeric ligatures.

OBJECTIVE: The purpose of this laboratory study was to evaluate changes in the pigmentation of esthetic elastomeric ligatures after immersion in a staining solution. METHODS: Sixty ligatures were selected and divided into 12 groups according to their brand and also considering their condition, i.e., unstretched or stretched. The groups were divided into: Morelli (clear), TP Orthodontics (clear), American Orthodontics (clear), 3M/Unitek (clear), American Orthodontics (pearl color) and 3M/Unitek (pearl color), separated in groups of 5 unstretched and 5 stretched ligatures. Assessment of their color changes was performed by means of digital photograph and computer analysis using Adobe Photoshop. Standardized digital photographs were taken at T0 (before the staining process, with unstretched ligatures) and at T1 (following the 5-days staining process). The staining solution was composed of artificial saliva and foods with staining potential. At T1 the ligatures were either stretched or unstretched. RESULTS: The results of this study showed that esthetic elastomeric ligatures are prone to staining. Among the evaluated brands, TP Orthodontics and American Orthodontics clear ligatures were the most stable. Moreover, 3M/Unitek pearl ligatures demonstrated statistically significant changes in all variables. CONCLUSIONS: Esthetic elastomeric ligatures are susceptible to staining and no statistically significant difference was found between unstretched or stretched ligatures, with the sole exception of the TP Orthodontics brand. The 3M/Unitek's pearl color ligatures displayed the greatest staining potential.