Prevalence and distribution of bone defects in moderate and advanced adult periodontitis

The purpose of the present investigation was to evaluate the prevalence and distribution of different forms of bone defects using direct observation during periodontal surgery. 286 patients with moderate or advanced adult periodontitis diagnosed during clinical and radiographic examination provided a sample of 5476 teeth. After full thickness mucoperiosteal flaps were raised, osseous defects were explored and classified according to their morphology as interdental craters, hemisepta and infrabony defects with 1, 2, 3 or 4 osseous walls. 981 defects were detected; 533 were in the maxilla and 448 in the mandible (15.4% and 22.4%, respectively, of the teeth examined). The posterior mandibular segment had the highest % of teeth with defects (33.8%) followed by the posterior maxillary segment (19.9%). The proportions of teeth with defects in the anterior segments of both arches were similar. The comparison between maxilla and mandible showed a highly significant difference for the posterior segments (p= 0.00001) but no difference for the anterior segments (p=0.88). The distribution of defects differed between the maxilla and the mandible, both for the posterior and anterior segments. Craters accounted for almost half the defects, being more prevalent in posterior segments, while hemisepta formed the lowest proportion. Anatomical variations in shape and the original morphology of the alveolar bone between the maxilla and the mandible and the anterior and posterior regions might have been the reason for the differences observed.