THE REVERSAL LINE MAY BE A KEY MODULATOR OF OSTEOBLAST FUNCTION - OBSERVATIONS FROM AN ALVEOLAR BONE WOUND-HEALING MODEL

The reversal line demarcates the cessation of osteoclast activity from the commencement of osteoblast activity at a remodeling site in bone. It is a seam between segments of bone that are formed at different ti mes. We believe that the reversal line contains regulatory signals tha t, in part, control osteoblast activity. We have conducted a pilot stu dy to examine the fate of reversal lines during abnormal bone remodeli ng in alveolar bone. A surgical periodontal defect was created in a Cy nomolgus monkey (Macaca fascicularis), allowed to heal in the presence of plaque, and evaluated histologically. In this model, there is an a cute inflammatory reaction followed by compromised bone formation. Wov en bone rather than lamellar bone was deposited in the defect. A strik ing finding in this wound-healing model was the disruption of the carb ohydrate material along the reversal line. This supports our theory th at disruption of the signaling molecules in the reversal line may be r esponsible for uneven woven bone formation.