Association Between Hypomineralisation of Second Primary Molars and Tooth Agenesis.

BACKGROUND: Hypomineralisation of second primary molars (HSPM) is an enamel defect with a multifactorial and potentially genetic aetiology. While the association between enamel defects and dental anomalies is a relatively recent area of investigation, it has not yet been explored specifically in cases of HSPM. AIM: To assess the association between HSPM and tooth agenesis (TA). DESIGN: A retrospective cross-sectional study was performed using pre-treatment records of patients aged 7-12 years. A total of 285 patient records were evaluated. Statistical analyses were performed using the Fisher's exact test and logistic regressions. RESULTS: A higher prevalence of TA was observed among children with HSPM-affected teeth (95% CI: 1.07-3.17, φ-coefficient: 0.238, PR: 1.84). Individuals with severe HSPM had significantly greater odds of TA (OR = 12.47; p < 0.001; 95% CI: 3.47-24.70). Patients with HSPM had a significantly higher likelihood of experiencing TA (OR = 6.97), particularly second premolar agenesis (OR = 11.80; p < 0.001; 95% CI: 2.83-49.10). CONCLUSION: An association was found between HSPM and TA, particularly involving mandibular second premolars. Moreover, increased HSPM severity was linked to a higher risk of developing TA.