# Prevalence and Radiological Evaluation of Primary Molar Infraocclusion in a Group of Turkish Children: A Retrospective Study

## TL;DR

This study found that infraocclusion in primary molars is uncommon but often linked to dental issues and affects treatment decisions in Turkish children.

## Contribution

The study provides new insights into the prevalence and radiological associations of infraocclusion in primary molars among Turkish children.

## Key findings

- Infraocclusion was most common in mandibular second primary molars and at age 9.
- Severe infraocclusion was linked to higher extraction rates and fewer restorative treatments.
- Dens invaginatus and hypodontia were the most common dental anomalies associated with infraocclusion.

## Abstract

Background: This study aimed to determine the prevalence of infraocclusion in primary molars, its distribution according to age, gender, and location, dental anomalies associated with infraocclusion, radiographic findings related to infraocclusion, and treatments applied to affected teeth. Methods: A total of 8452 digital panoramic radiographs of children aged 7–11 years (2019–2022) were retrospectively evaluated for infraocclusion of primary molars. Radiographs were assessed by calibrated examiners, and infraocclusion severity was classified according to the Brearley and McKibben system. The presence of permanent successors, applied treatments, and associated dental and radiographic findings were recorded. Data were analyzed using descriptive statistics and chi-square tests (SPSS 28.0). Results: Infraocclusion was most frequently observed in mandibular second primary molars and was most prevalent at the age of 9. The majority of cases were mild (49.5%), followed by moderate (29.8%) and severe (20.7%). A significant correlation was found between infraocclusion severity and radiographic findings such as adjacent tooth tipping, supraeruption of opposing teeth, and eruption disturbances of permanent successors (p < 0.05). A statistically significant relationship was also observed between infraocclusion severity and treatment modality (p < 0.05). As infraocclusion severity increased, restorative treatment decreased and extraction rates increased. In 10.3% of cases, no permanent successor was present beneath the affected tooth. Dens invaginatus and hypodontia were the most commonly associated dental anomalies. The overall prevalence of infraocclusion was 3.6%, with no significant gender difference (p > 0.05). Conclusions: Although infraocclusion is relatively uncommon in primary molars, the present findings highlight its frequent associations with dental anomalies and variations in permanent successor presence. These results emphasise the importance of careful radiographic evaluation and follow-up in children with infraoccluded primary molars. Future longitudinal studies are needed to better understand the aetiology and progression of infraocclusion.