Chapter 24 - Bone Loss and Patterns of Bone Destruction

Abstract

This chapter discusses periodontal bone loss as a consequence of inflammation and as modified by other factors, such as trauma from occlusion. The inflammatory process develops as a response to the bacterial biofilm front and follows the path of the large blood vessels in the affected area. The average progression of bone loss in untreated periodontitis is 0.2 to 0.3 mm per year, but the range varies substantially depending on the individual’s susceptibility to the disease. The destructive radius of action of the inflammatory process is estimated to be 1.5 to 2.5 mm. Depending on the anatomy of the affected area, the inflammatory process may induce horizontal or vertical bone loss. Horizontal bone loss is the most prevalent form of bone destruction in periodontitis. Vertical bone loss is most commonly observed in areas of greater bone volume. Vertical bone loss is classified according to the number of bony walls surrounding the defect. Bone loss in interradicular areas may also be horizontal or vertical and is classified according to the degree of bone destruction in the furcation space relative to the point where the roots bifurcate or trifurcate. Trauma from occlusion may lead to periodontal bone loss around teeth. In the absence of biofilm-induced gingival inflammation, such bone loss is not accompanied by clinical attachment loss and is reversible. When combined with biofilm-induced gingival inflammation, trauma from occlusion may accelerate the rate of bone loss and/or alter the course of the inflammatory process, possibly favoring the formation of vertical defects. Systemic conditions that may be associated with periodontal bone loss include osteoporosis, hyperparathyroidism, leukemia, and histiocytosis X.