Age-related dentoalveolar changes continue from adolescence into late adulthood, supporting the concept that occlusion remains dynamic throughout life.
Key Findings
Results
Arch depth decreased significantly in both maxillary and mandibular arches over the 50-year observation period.
Study followed 30 orthodontically untreated subjects (11 males, 19 females) across four time points
Mean ages at examination were 13 (T1), 16 (T2), 31 (T3), and 62 years (T4)
Changes were assessed using the Wilcoxon signed-rank test on digitally derived measurements from 3D-scanned stone casts
Arch depth was classified as a sagittal measurement and showed significant decrease in both arches
Overjet, also a sagittal measurement, remained stable across all time points
Results
Overbite decreased significantly over the observation period while clinical crown height increased significantly in both arches.
Both overbite and clinical crown height were classified as vertical measurements
Clinical crown height increased significantly in both maxillary and mandibular arches
These vertical changes were tracked across all four time points from age 13 to 62
Measurements were digitally derived from high-resolution 3D scanner digitizations of stone casts
Results
Palatal height increased significantly up to age 31 and the curve of Spee decreased significantly by age 16.
Palatal height showed significant increases from adolescence through early adulthood (up to T3, mean age 31 years)
The curve of Spee, a vertical measurement, decreased significantly by age 16 (T2)
These findings were based on digitally assessed measurements from 3D-scanned dental casts
Eleven variables in total were digitally assessed across the four time points
Results
Mandibular intercanine width decreased significantly, while maxillary and mandibular intermolar widths and maxillary intercanine width showed no significant changes.
Transverse measurements included both intercanine and intermolar widths in both arches
Mandibular intercanine width was the only transverse measurement to show a significant change
Maxillary intercanine width remained stable across all four time points
Both maxillary and mandibular intermolar widths showed no significant changes from age 13 to 62
Results
Maxillary and mandibular arch lengths decreased significantly at all time points, accompanied by significant increases in space deficiency and mandibular incisor irregularity throughout the observation period.
Arch length decreases were statistically significant at all time intervals assessed
Space deficiency increased significantly across all four time points
The irregularity index of the mandibular incisors increased significantly throughout the entire 50-year observation period
These space-related changes were observed in both arches
The sample consisted of 30 subjects with normal occlusion recruited through the Public Dental Health Care system
Methods
The study used digitally derived measurements from 3D-scanned stone casts on 30 orthodontically untreated subjects with normal occlusion followed over approximately 50 years.
Sample comprised 11 males and 19 females
Subjects were recruited through the Public Dental Health Care system
Stone casts of maxillary and mandibular arches were digitized using a high-resolution 3D scanner
Eleven variables were assessed: overjet, overbite, intercanine width, intermolar width, arch depth, palatal height, curve of Spee, clinical crown height, arch length, space deficiency, and irregularity index
Strict inclusion and exclusion criteria were applied; all subjects were orthodontically untreated with normal occlusion
What This Means
This research followed 30 people with naturally well-aligned teeth from age 13 to approximately age 62, taking measurements of their dental arches at four points in time using detailed 3D scans of dental molds. The goal was to understand how the teeth and jaw structures change naturally over a lifetime, even without orthodontic treatment. The study found that many aspects of tooth alignment and jaw shape continue to change well into adulthood — not just during the teenage years.
Key findings include that dental arches tend to get shorter and narrower (particularly the lower front teeth area), crowding of the lower front teeth increases over time, and the space available for teeth decreases progressively. Meanwhile, teeth appear to grow taller (clinical crown height increases), the roof of the mouth gets higher into early adulthood, and the vertical overlap of the front teeth (overbite) decreases. Notably, the width across the back molars remained stable, and the horizontal protrusion of the upper front teeth (overjet) did not change significantly.
This research suggests that the mouth is not a static structure — it continues to change throughout adult life, even in people who never had braces. For orthodontic patients and clinicians, these findings highlight why retainers and long-term retention strategies may be important well beyond the end of active treatment, and they provide a useful baseline reference for understanding what is 'normal' dental aging versus changes that might need intervention.
Basim A, Naoumova J, Leffler K, Johansson K, Persson M, Al-Taai N. (2026). Digital analysis of age-related dentoalveolar changes: a 50-year longitudinal study.. Progress in orthodontics. https://doi.org/10.1186/s40510-026-00643-0