Topographic Study of Extracted Molars with Advanced Furcation Involvement: Furcation Entrance Dimension and Molar Type

This study investigated the topography of the furcation entrance dimension (FED) on molars with advanced furcation involvement (FI). The sample pool consisted of 169 maxillary and mandibular molars from a group of 165 individuals with severely advanced periodontal destruction. The subjects included men and women aged 24 to 84 years (mean, 47.8 ± 7.2 years). The FEDs of the maxillary buccal, mesial, and distal surfaces as well as the mandibular buccal and lingual surfaces were measured under a stereomicroscope and clarified into grades I (FED < 0.55 mm), II (0.55-0.75 mm), and III (> 0.75 mm) using automatic grading system software designed by our research associates. The differences and relationships among molar location, furcation site, and FED grade were analyzed using the chi-square test. There was a significant difference among buccal (BFED), mesial (MFED), and distal (DFED) FEDs in both the maxillary first (χ24 = 58.915, p < 0.001) and second (χ24 = 66.839, p < 0.001) molars. The relationship between molar type and FED grade was statistically significant for both the BFED (p < 0.001) and the DFED (p < 0.001) of maxillary molars, as well as for both the BFED (p < 0.0001) and LFED (p < 0.0001). The difference in FED grade between the first and second molars was statistically significant in both maxillary (p < 0.001) and mandibular (p < 0.0001) molars. There was a significant relationship between FED grade and tooth location at molars with advanced FI