To assess the prevalence of initial proximal caries in 3-6-year-old children

with OXIS contacts [O (open contact), X (point contact), I (straight contact), and S (curved contact)]. Their significance can be understood through their impact on dental health, occlusion, and overall oral development.

Materials and Methods: A sample of 167 primary molar contacts from children aged 3–6 years was examined. Clinical assessments were conducted using mouth mirrors and probes under adequate lighting to classify contacts as O, X, I, or S. Intraoral periapical radiographs or Radiovisiography were used to detect initial proximal caries. The association between contact type and caries prevalence was analysed using the Chi-square test.

Clinical Significance: Understanding contact types aids clinicians in recognising caries-prone areas and restoring complex contacts to reduce caries risk, enhancing oral health outcomes.

Previous studies have different criteria to determine the nature of contact between primary molars as open/ closed contact^12,13. They concluded that closed contact has a potential risk for caries. In the present study, I type of contact was most prevalent with initial caries followed by S type, consistent with findings of Kirthiga M et al, Muthu M S et al. Those authors reported that S and I type contacts had higher odds of developing caries than X and O type. This susceptibility could be due to higher plaque accumulation that may occur beneath closed contacts and additionally retained plaque in these areas may be difficult to remove using standard tooth brushing methods. The concavity followed by convexity in this design (S type) forms a favourable niche for plaque accumulation. 

The assessment of contact areas is essential to understand the risk of initial caries development and progression, to account for the preparation of proximal cavity and maintenance of appropriate contact after the placement of restorations and crowns.