Aging of the normal occlusion.

Objectives: The aim of this study was to evaluate the qualitative occlusal changes in individuals with normal occlusion during a period of 47 years.
Materials and Methods: The sample comprised dental models of 20 subjects with normal occlusion (8 males; 12 females) taken at 13.2 years (T1) and 60.9 years of age (T2). The occlusal features were evaluated with the objective grading system (OGS) and with the six keys to normal occlusion (SKNO). The subjects also answered a questionnaire on the aesthetic and occlusal self-perception at T2. Comparisons from T1 to T2 were performed with paired t- and McNemar tests (P less than 0.05).
Results: OGS analysis showed a significant improvement in the marginal ridge levelling and tooth buccolingual inclination. There was a significant deterioration of the antero-posterior occlusal relationship from T1 to T2. Subjects without tooth loss showed a dental alignment worsening between time points. The marginal ridges, buccolingual inclination, and interproximal contacts improved. The SKNO analysis showed a significant deterioration of the maxillary second molars buccolingual inclination and an improvement of the maxillary second molar angulation. All patients were satisfied with their smiles, and 60 per cent of the subjects had no complaints. Dental crowding caused dissatisfaction in 35 per cent of the sample.
Limitations: A limitation of this study was the high prevalence of tooth loss in the sample from T1 to T2. Only 30 per cent of the subjects had no tooth loss in T2.
Conclusions: The aging process slightly deteriorates some occlusal features of individuals with normal occlusion. However, most individuals were satisfied with their aesthetics and occlusal comfort at the sixth decade of life.
(© The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)