RESUMO
This study investigated the association between demographic, socioeconomic conditions, oral health behavior and several clinical factors that are enrolled on caries development and the quality of amalgam restorations. Seventy-eight amalgam restorations were selected from 44 patients of the Operative Dentistry clinic of Universidade Federal de Pelotas. The restorations had been placed five years before by undergraduate students using pre-established criteria. The quality of amalgam restorations was evaluated according to modified United States Public Health Service (USPHS) criteria. Demographic (age, gender, ethnic origin) and socioeconomic (income, educational level and profession) conditions, oral health behavior (dental floss, tooth brushing and sucrose ingestion) and clinical variables (previous caries experience, periodontal conditions tooth position surface involved, quantity of dental plaque and caries activity) were investigated. The results showed that 51 (65.4%) of the restorations were unsatisfactory, for which finishing and polishing, or even repair or replacements were required. Twenty-seven (35%) of the restorations were classified as unacceptable because of secondary caries. Statistical analysis (Chisquare and Fischer's exact test) showed that some variables were associated with the quality of restorations: age, educational level, profession, Decayed, Missed, Filled Teeth (DMFT) index, caries activity, tooth surface, and quality/quantity of plaque. The findings suggest that the quality of amalgam restorations may be affected by different factors, and secondary caries were the main reason for restoration replacement.