Buccal alveolar exostoses: Prevalence, characteristics, and evidence for buttressing bone formation

Background: Buttressing bone formation has been described as the developmen t of thickened or exostotic buccal alveolar bone in response to heavy occlu sal forces. Little supporting evidence for this model has been found in pre vious literature, however and there is little seen on the prevalence or cha racteristics of buccal alveolar exostoses. Methods: A sample of 416 selected teeth and investing bone in 52 modern ske letal specimens at the National Museum of Natural History were examined. Tw o measures of heavy occlusal function-periodontal ligament (PDL) width and occlusal attrition-were analyzed for their relationship to three parameters of buccal alveolar bone (exostoses, lipping, and overall thickness). Results: Buccal alveolar bone enlargements were found in 25% of all teeth e xamined: 18% were expressed as marginal bony lippings and 7% as buccal exos toses. Exostoses were mainly seen around maxillary molars and bicuspids, es pecially in males, while lippings were seen in molars, bicuspids, and mandi bular incisors, with even gender distribution. When findings were controlle d for arch and tooth type, no significant correlations were found between w ider PDL spaces or occlusal attrition and exostotic, lipped, or thicker alv eolar bone. Conclusions: These results indicate a lack of anatomic evidence for the the ory of buttressing bone formation and suggest that other factors may be of greater importance in the etiology of buccal bone enlargements. Incidentall y, no correlation was found between widened PDL spaces or severe occlusal a ttrition and the presence of cervical loss of tooth structure, which casts doubt on the currently popular concept of abfraction.