RELATIONSHIP BETWEEN SR85 UPTAKE AND HISTOLOGICAL CHANGES DURING HEALING IN DENTAL EXTRACTION WOUNDS IN RATS

Sr85 uptake and histological aspects of healing in dental extraction wounds of rats were studied at varying time intervals from 0 to 42 days following extraction of the maxillary left third molar. A total of sixty Sprague-Dawley female rats (approx. 100 days of age) were used, 50 were injected I.P. with approximately 5μCi of Sr85Cl2 (0.5 ml vol.) 24 hr prior to sacrifice, while the remaining uninjected 10 animals were used for histological study. Radioactivity of bone from the right and left maxillary third molar areas was measured in a well-type scintillation detector with a thallium-activated sodium iodide [NaI(T1)] crystal and expressed as either percentage of injected dose (% I.D.) or counts/min/unit of fresh weight to the nearest 0.1 mg. The ratio of Sr85 uptake was expressed as extracted site counts divided by non-extracted counts. When the ratio was less than 1.00, the histologic sections showed evidence of bone resorption and slight new bone formation whereas when the ratio was greater than unity, histologic sections showed marked evidence of predominant new bone formation. Significant differences were found between the uptake of Sr85 (% I.D./mg) in extraction and non-extraction sites during the period of 0 to 42 days (F = 5.81, P < 0.05). The differences in Sr85 uptake at the 10th and 14th day correspond with the times of greatest histologic activity of new bone formation in the healing sockets and extra-alveolar sites. © 1969.