Digital analysis of age-related dentoalveolar changes: a 50-year longitudinal study

With the growing demand for orthodontic treatment among adults, a clear understanding of the age-related dentoalveolar changes has become increasingly important for accurate diagnosis, treatment planning, and long-term retention strategies. This study aims to characterize dentoalveolar changes in individuals with normal occlusion from early adolescence (13 years) to late adulthood (62 years) across four time points, using digitally derived measurements and strict inclusion and exclusion criteria.

Thirty orthodontically untreated subjects (11 males, 19 females) recruited through the Public Dental Health Care system in, were examined at mean ages of 13 (T1), 16 (T2), 31 (T3), and 62 years (T4). Stone casts of the maxillary and mandibular arches were digitized using a high-resolution 3D scanner. Eleven variables were digitally assessed: overjet, overbite, intercanine width, intermolar width, arch depth, palatal height, curve of Spee, clinical crown height, arch length, space deficiency, and irregularity index. Changes across time points were analyzed using the Wilcoxon signed-rank test.

Sagittally, overjet remained stable, whereas arch depth decreased significantly in both arches. Vertically, overbite decreased significantly, while clinical crown height increased significantly in both arches. Palatal height increased significantly up to age 31, and the curve of Spee decreased significantly by age 16. Transversely, maxillary and mandibular intermolar widths, as well as maxillary intercanine width, showed no significant changes, whereas mandibular intercanine width decreased significantly. In terms of space, maxillary and mandibular arch lengths decreased significantly at all time points, accompanied by significant increases in space deficiency and in the irregularity of the mandibular incisors throughout the observation period.

Age-related dentoalveolar changes continue from adolescence into late adulthood, supporting the concept that occlusion remains dynamic throughout life. These longitudinal findings provide clinically relevant reference data for orthodontic diagnosis, treatment planning, and the development of effective long-term retention strategies.