Análise em modelos digitais dos efeitos sagitais e transversais do arco lingual : estudo prospectivo

Abstract

In preventive and interceptive orthodontics, the use of mandibular fixed lingual arch is a commonly accepted procedure to maintain arch perimeter by preventing mesial tipping or drifting of the mandibular molars. Despite its widespread use, comparatively little is known concerning the efficiency of a lower lingual holding arch as a space holding device and its effect on the dimensions of the lower arch. Objectives: To quantify the arch dimensional changes that occur during the lingual arch use. Digital models were used to evaluate sagittal and transversal changes in the lower arch. Materials and Methods: The sample consisted of 38 patients (20 boys, 18 girls), with a mean age of 9.2 years (range, 7-12.2 years). For the control group, a retrospective sample of 21 patients (11 boys, 10 girls) with a mean age of 9.4 years (range, 7.8 - 12.3 years) was selected. Patients were classified according to growth pattern, for SN.GoGn ≤ 32º (Horizontal) and for SN.GoGn> 32º (Verticals). A total of 118 dental cats were scanned (3Shape R700, Copenhagen, Denmark). The OrthoAnalyzer software (3Shape, Copenhagen, Denmark) was used to evaluate the files. The independent t-test was used to evaluate the experimental group and control group. And the paired t-test was used for a comparison between groups. Results: In the lingual arch group, the arch length was not significant (p >0,05). The intermolar width significantly increase (p <0.001). Buccolingual inclination of the lower incisors was statistically significant (p <0.001). The lingual arch was more effective for preserving the arch length in vertical patients (p< 0,001) and buccolingual inclination of the lower incisors was statistically significant for these patients (p <0.001) Conclusions: The lingual arch is good appliance for preserving arch length, mainly in vertical patients, but with a potential for buccolingual inclination of the lower incisors. The intermolar width, and buccolingual inclination of the molars and lower incisors significantly increased.