PURPOSE:This study aimed to explore the relationships among tooth replacement, number of present natural teeth, and sociodemographic and behavioral factors in an adult population in Bulgaria. MATERIALS AND METHODS:Quota sampling was used to recruit 2,531 dentate subjects aged 20 years and over from the capital city and four main urban centers, four towns, and seven small towns and villages of Bulgaria. Potential candidates for tooth replacement were classified as having functional dentitions (26 to 27 or 20 to 25 natural teeth present) or subfunctional dentitions (16 to 19 or 2 to 15 natural teeth present), not including third molars. Multiple logistic regression analyses were performed to determine the associations between tooth replacement and the factors of interest. RESULTS:Of the included subjects, 37% presented with tooth replacement, while 19% presented with fewer than 20 natural teeth. Molars were replaced significantly less often (P ≤ .017) than premolars and anterior teeth. The presence of tooth replacement was more likely in subjects with 2 to 15 teeth (odds ratio: 1.62) and less likely in subjects with 26 to 27 teeth (odds ratio: 0.29), but no significant difference was detected between subjects with 16 to 19 and 20 to 25 teeth. Tooth replacement was associated with age, occupational status, frequency of dental visits, and toothbrushing habits. CONCLUSIONS:In this Bulgarian population, the variables number of present teeth, age, dental visits, and toothbrushing were relevant factors with respect to tooth replacement. The cutoff value of 20 teeth did not discriminate high-risk from low-risk subjects.