Prevalence and correlation of OXIS contacts using Cone Beam Computed Tomography (CBCT) images and photographs

The contact areas in between primary teeth are broader, flatter, and located further cervically when compared with the contact areas of permanent molars.

We investigated the prevalence of interproximal contact area types of primary molars using CBCT images in children aged 3-10 years. Our second objective was to correlate OXIS contact areas when observed with CBCT images and clinical photographs.

A retrospective cross-sectional study was performed with 367 CBCT images of children, aged 3-10 years, obtained from Children's Dental Centre, South Korea. The type of contacts in between primary molars was scored at various levels, specifically, occlusal, middle, and cervical thirds, according to OXIS criteria. Following this, the same patient's records were checked for the presence of clinical photographs and scored according to the same criteria. Prevalence was stated as percentages along with numbers. Chi-square test was applied to determine association of contact areas across genders and arches. The correlation between the two methods was done by Cohen's Kappa correlation test.

The prevalence of the OXIS contacts obtained from CBCT images was as follows: I (79.7%), followed by X (10.0%), S (6.6%), and, finally, O (3.7%). The overall score of all the 1343 contact areas matched with the score observed at the occlusal third. All included contacts were of O (open) type at cervical third, and 1,231 contacts were of O (open) type at the middle third. Significant results were observed with respect to arches (P < .001). The correlation between the two methods was found to be 0.958.

The contact area observed at the occlusal level determined the overall type of contact based on OXIS criteria. Thus, reports in the literature concluded that contact areas are broad, flat, and extend further gingivally should be revised. The study also concluded almost perfect agreement between CBCT images and clinical photographs.