RESUMEN
BACKGROUND: This retrospective study evaluates and assigns scores to six prognostic factors and derives a quantitative scoring index used to determine the periodontal prognosis on molar teeth. METHODS: Data were gathered on 816 molars in 102 patients with moderate-to-severe periodontitis. The six factors evaluated (age, probing depth, mobility, furcation involvement, smoking, and molar type) were assigned a numeric score based on statistical analysis. The sum of the scores for all factors was used to determine the prognosis score for each molar. Only patients with all first and second molars at the initial examination qualified for the study. All patients were evaluated a minimum of 15 years after treatment. RESULTS: The post-treatment time ranged from 15 to 40 years and averaged 24 years. When the study was completed, 639 molars survived (78%), and, of those surviving molars, 588 survived and were periodontally healthy (92%). In molars with lower scores (scores 1-3), the 15-year survival rates ranged from 98% to 96%. In molars with middle scores (scores 4-6), the 15-year survival rates ranged from 95% to 90%, and, for molars with higher scores (scores 7-10), the survival rates ranged from 86% to 67%. CONCLUSION: The present results indicate that the periodontal prognosis of molars diagnosed with moderate-to-severe periodontitis can be calculated using an evidence-based scoring index.