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Influence of growth pattern on the alveolar cortical bone thickness and the correlation with stability of mini-implants

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Author(s):
Carolina Carmo de Menezes
Total Authors: 1
Document type: Master's Dissertation
Press: Bauru.
Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
Defense date:
Examining board members:
Guilherme dos Reis Pereira Janson; Daniela Gamba Garib Carreira; Flávio Augusto Cotrim Ferreira
Advisor: Guilherme dos Reis Pereira Janson
Abstract

This study aimed the assessment of the craniofacial growth pattern influence on the alveolar bone cortical thickness as well as the evaluation of the stability of orthodontic mini-implants. The sample comprised 56 mini-implants inserted on the posterior buccal region of the maxilla of 30 patients with the purpose of orthodontic anchorage for the anterior retraction. Initially, patients were divided by FMA mean according to the growth pattern as: horizontal group (GH group) and vertical group (GV group). The alveolar cortical bone thicknesses were measured in the axial sections of the images of cone-beam computed tomography. The means found for each group were compared with the t test. Pearson´s correlation was performed for the values of growth pattern (FMA) and for the thicknesses of cortical bone. In order to evaluate the influence of growth pattern on the stability of mini-implants, these devices were divided in two other groups, according to the growth pattern as: GMI(H), horizontal and GMI(V), vertical. The mobility degree and success rate of mini-implants shown by these two groups were compared using Mann-Whitney tests and Fisher Exact test. Through these tests and the Chi-square test the influence of the following variables on the degree of stability were evaluated: soft tissue characteristics of the insertion site, sensibility degree, plaque retention around miniimplant, observation period and technique used. The results demonstrated that the thickness of the anterior buccal cortical bone (upper and lower) and the posterior cortical bone (lower) were greater for the GH group than for the GV group. There was a significant negative correlation between the FMA and the thicknesses of the lower anterior regions (buccal and lingual) and upper regions (buccal). No significant difference was found regarding the mobility degree and the success rate of miniimplants between the groups GMI(H) and GMI(V). Total success rate found was 89.29% and no variable showed to be related to the success of mini-implants. Nevertheless, a greater sensibility was observed in patients whose mini-implants presented mobility and the failure of these anchorage devices occurred in a short time after insertion. (AU)

FAPESP's process: 09/06925-0 - "Influence of growth pattern on the alveolar cortical bone thickness and the correlation with stability of mini-implants"
Grantee:Carolina Carmo de Menezes
Support Opportunities: Scholarships in Brazil - Master