Rate of Initial Proximal Caries Lesion Progression in High Caries-Risk Adults.

Abstract

Rationale: In adults, caries lesions develop predominantly on proximal surfaces; however, evidence regarding the rate of proximal caries progression in this population remains limited. A clearer understanding of the progression rate of proximal caries in adults is essential for establishing appropriate radiographic examination intervals and optimizing the timing of operative interventions.

Objective: To evaluate the rate of radiographic progression of initial proximal caries lesions and the factors associated with it.

Methods and materials: Serial bitewing radiographs from 105 patients, aged 18-61 years, were retrospectively analyzed for the progression of 364 enamel and outer dentin proximal caries lesions. The interval between baseline and follow-up radiographs ranged from six to 72 months. Lesion progression across study variables was summarized using descriptive statistics. A multivariable generalized estimating equation (GEE)-based Poisson regression model with robust variance estimation was performed to identify factors associated with proximal caries progression, including patient-level variables (age, gender, fluoride varnish exposure, plaque score, BOP score, DMFT, and DMFS) and tooth-level variables (jaw, tooth type, surface, and initial lesion depth), while accounting for clustering of lesions within patients and variable follow-up duration (p < 0.05; 95% CI).

Results: The mean interval between the initial and follow-up radiographs was 19.9 ± 12.6 months (median = 18 months). Caries progression was observed in approximately one-third of the initial proximal lesions (112 lesions; 30.8%). No lesions progressed from enamel to inner dentin, and only 12 of 43 outer dentin lesions advanced to inner dentin. According to multivariable GEE Poisson regression analysis, maxillary lesions exhibited a higher rate of progression than mandibular lesions (IRR 1.52; 95% CI 1.07 - 2.16), and lesions on distal surfaces demonstrated a higher progression rate than those on mesial surfaces (IRR 1.37; 95% CI 1.01 - 1.85).

Conclusion: The rate of proximal caries progression was relatively low. Tooth location (maxillary arch) and distal surfaces were the only significant predictors of lesion progression.