Phase 3- Association of OXIS contacts and proximal caries - Prospective study

Purpose: This study aimed to evaluate the association between contact areas of primary molar teeth and approximal caries after three years of observation.
Methods: This prospective cohort study included 1119 caries-free children, aged 3–4 years, from Puducherry, India. At baseline, 4476 contacts were assessed using OXIS criteria, which denotes O (open contact); X (point contact); I (straight contact) and S (curved contact). Two calibrated dentists measured dental caries at one-year intervals for three years. Poisson regression analysis with a multilevel approach was used to determine the association between contact type and approximal caries.
Results: Of 3,848 contacts observed at the end of three years, 499 (13·0%) were carious. The adjusted analysis revealed a significant association between contact type and approximal caries (p < 0·05). The risk ratios were 2.3 for X-type contacts (0·5–11·4, p = 0.307); 12.7 for I-type (4·1–39·6, p < 0·05); and 22.5 for S-type (7.2–70.6, p < 0.05), when compared with O-type.
Conclusion: Compelling evidence suggests that variations in contact type are significant in development of approximal caries. The S-type contact is the most susceptible to approximal caries, followed by the I type.