Tooth agenesis affects one in four individuals in a multicenter saudi sample: a cross-sectional study of hypodontia and regional variation.

Abstract

Background: Hypodontia is a common developmental dental anomaly with significant functional and esthetic consequences. However, large-scale multicenter evidence from Saudi Arabia remains limited. This study aimed to estimate the prevalence of hypodontia and identify its demographic and regional determinants across five regions of the Kingdom.

Methods: This retrospective multicenter cross-sectional study analyzed 3,170 panoramic radiographs from seven academic institutions across Central, Eastern, Western, Northern, and Southern Saudi Arabia (2015-2025). Saudi nationals aged 7 to less than 21 years were included, while individuals with craniofacial anomalies, systemic conditions affecting tooth development, prior orthodontic treatment, and oligodontia were excluded. Data were analyzed using chi-square tests and multivariable logistic regression.

Results: The overall prevalence of tooth agenesis, including third molars, was 24.3% (n = 769; 95% CI: 22.8-25.8%). When third molars were excluded, the prevalence of hypodontia was 6.47% (n = 205; 95% CI: 5.2-6.9%). Without third molars, prevalence was 6.61% among females and 6.29% among males, with no statistically significant sex-related difference (p = 0.767). A small age difference was observed between participants with and without hypodontia (p = 0.001); however, age was not independently associated with hypodontia in the adjusted model (OR = 0.980, p = 0.369). Significant regional variation was observed in the adjusted model, with higher odds in the Eastern (OR = 1.56, p = 0.034) and Western (OR = 1.67, p = 0.013) regions compared with the Central region.

Conclusions: Tooth agenesis, including third molars, was observed in approximately one in four individuals (24.3%) in this multicenter study, while conventional hypodontia, excluding third molars, affected approximately 6.47% of participants. Significant regional variation was observed, with no significant sex difference. These findings provide important multicenter epidemiological evidence and support early diagnosis and region-specific preventive and treatment strategies.