Assessment of contact area variations in primary molars of children based on the OXIS classification

Background: The localization and depth of caries in primary teeth vary based on eruption timing, mouth position, and contact type with adjacent teeth upon occlusion. Methods: On plaster models of 153 children aged 3 to 10 years, obtained from Gaziantep University Faculty of Dentistry, 373 contact points created by caries-free primary molars were assessed. The OXIS criteria were used to evaluate the type of contact between primary molars. In addition to figures, prevalence was expressed as percentages. The association between contact areas, age, gender, and arches was examined using the chi-square test. Results: The most common contact type was Type I (50.94%), followed by Type S (29.75%), Type X (16.09%) and the least common, Type O (3.22%). Type S was most prevalent in the maxilla (46.63%) and Type I in the mandible (68.33%). After age 6, Types I and S contacts increase, while Type O is more common in children under 6. No gender differences were found. Conclusions: The OXIS classification can be regarded as a systematic approach to investigate the impact of contact areas on caries and the prevalence of contact areas in various ethnic groups.