Análise orofacial de indivíduos com osteogênese imperfeita: índices radiomorfométricos, dimensão fractal do osso mandibular e má oclusão

Abstract

Osteogenesis Imperfecta (OI) is a rare genetic disease characterized by fragile bones with recurrent fractures. In most cases, OI is caused by mutations in the COL1A1 or COL1A2 genes which encode type I collagen. Mutations in new genes involved in the bone metabolism pathway have been discovered. OI is associated with dental and craniofacial alterations, the most prevalent being dentinogenesis imperfecta and malocclusion. The literature has shown that it is possible to predict the risk of bone fracture when analyzing radiomorphometric indices and fractal dimension (FD) of the mandible in panoramic radiographs. The objective of this research was to verify if there are differences in the occlusion pattern, in the cortical and in the mandibular bone trabeculate of individuals with OI when compared to individuals without OI. Thus, the thesis has the presentation of two scientific articles. The first article aimed to analyze two radiomorphometric indices, the mandibular cortical index (MCI) and the mentual index (MI), and the FD of the mandibular bone trabeculate of individuals with OI and compare with individuals without OI. A cross-sectional study, matched by age and sex, was carried out with 20 individuals with OI and 40 without OI. Data were obtained through panoramic radiographs of patients with OI and without OI treated at the Faculty of Dentistry of the Federal University of Minas Gerais. The study was approved by the Research Ethics Committee at UFMG (protocol 02470518.3.0000.5149). Paired t-test (p<0.05) was used to compare MI and DF values. The chi-square test (p<0.05) compared the ICM between groups. The mean age of both groups was 13.10 years (± 6.57). The mean value of MI was 2.08 (±0.79) in the group of individuals with OI and 2.91 (±0.60) for individuals without OI (p<0.001). The fractal dimension of mandibular trabecular bone was also analyzed in three regions of interest (condyle, angle and premolar region). ICM grade C3 was more frequent among individuals with OI (p<0.001). Individuals with OI had lower MI and DF values, in addition to worse mandibular cortical morphology. The second article, a systematic review and meta analysis (already published), aimed to assess whether individuals with OI are more affected by malocclusion than normotypical individuals. A search was carried out in the main bases. Risk of bias assessment and strength of evidence analysis were conducted. Compared with individuals without OI, the group with OI was 19.69 times more likely to have Angle Class III malocclusion (OR = 19.69, CI: 9.00–43.09) and to have greater anterior crossbite (MD = 6.08, CI: 2.40–9.77). Subjects without OI had a significantly greater ANB angle (MD= 3.88, CI: 1.15–6.61) and SNA angle (MD= 2.11, CI: 0.24–3.98) compared to subjects with hi. No difference between groups was found for SNB (MD = −0.50, CI: −2.21 to 1.21) and open bite (MD = 0.98, CI: −0.29 to 2.25). Most of the included studies were of moderate methodological quality. The strength of the evidence was low or very low. The occurrence of Angle Class III malocclusion and anterior crossbite was higher among individuals with OI compared to those without OI