Maturational changes of the normal occlusion: a 40-year follow-up

• Ano de defesa: 2017
• Autor(a) principal: Massaro, Camila da Silveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Aging; Dental models; Dental occlusion; Envelhecimento; Modelos dentários; Oclusão dentária
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25144/tde-29112021-101647/

Purpose: This study aimed at evaluating the changes in the dental arch dimensions, tooth size and incisor crowding in individuals with normal occlusions over a 40-year period. Methods: A sample of 82 White-Brazilian subjects with normal occlusion evaluated at adolescence (T1) and early adulthood (T2) was recruited for a T3 evaluation at the sixth decade of life. The exclusion criteria were history of orthodontic treatment, complete tooth loss and absence of dental model at any of the three time points. The final sample was composed by dental casts of 22 subjects (12 males and 10 females) obtained at a mean age of 13.3 years (T1), 17.8 years (T2) and 60.9 years (T3). The following variables were measured in digital casts: mesiodistal tooth size, clinical crown height, arch length, arch width, arch perimeter, palatal depth, maxillary and mandibular incisor crowding (Littles irregularity index), overjet, overbite and curve of Spee. Interphase changes were evaluated using dependent ANOVA and Tukey tests, and sex comparisons were performed using independent t-tests (p<0.05). Results: An increase of the clinical crown height in the posterior teeth and an increase of incisor crowding were found. Mesiodistal tooth size decreased from T2 to T3. A decrease of mandibular intercanine width, arch length, arch perimeter, overbite and curve of Spee was observed from 13 to 60 years of age. No changes were noted for the overjet. The palatal depth increased between 13 and 17 years and remained stable from 17 to 60 years of age. Males had a greater reduction in the overbite when compared with females. Conclusion: Normal occlusion subjects demonstrated dimensional changes in tooth size and alignment, overbite and arch dimensions from adolescence to late adulthood. Aging of normal occlusion might be prevented by bonding a mandibular 3x3 bar retainer during adolescence and reconstructing worn canine cusp tips during adulthood.