A model for decision making regarding periodontal treatment needs.

The aim of this study was to present a tentative model for decision making regarding periodontal treatment needs, based on the amount of remaining periodontal bone support. In the model presented, a maintained alveolar bone height of one third of the root length at the age of 75 years was regarded to be a reasonable goal. The data analyzed were derived from a patient sample of 194 dentate individuals aged 25-70 years from whom 2 full mouth series of intraoral radiographs, approximately 10 years apart, were available. For teeth present at both examinations, the radiographs were evaluated with respect to alveolar bone levels at the mesial and distal aspect of the teeth, i.e., the distance between the cemento-enamel junction and the most coronal level of the bone support. Longitudinal alveolar bone level change was determined for each tooth site and the alteration in alveolar bone height per 5-year interval between 25 and 75 years of age was described. Based on the calculated mean bone loss data, a rate factor was determined for each tooth site and used in the final description of the alveolar bone level for each particular tooth site at ages 30, 35, 40, ..., and 70 years, depicting the amount of bone loss beyond which therapeutic intervention has to be made in order to meet the defined goal of the tentative model. The relevance of the model and its applicability are discussed.