[Structural changes in jaw bone marrow after hemorrhagic infiltration].
Normal saline solution flushing of the inner mandible was done on twelve dogs, to confirm the effect of hemorrhagic infiltration that occurs in the fatty marrow. Histological examinations were performed at 1 hour, 5 days, 10 days, 2 weeks, 1 month and 3 months.


RESULTS
1. Marrow extrusion occurred at approximately 1 atm (injection pressure). 2. At 1 hour, marrow cavities located between the 2 injection holes with the exception of the extraction sites were filled with infiltrated blood cells. Fatty marrow was moderately replaced by the infiltrated blood cells in the extraction cavities and outer distal areas of the injection holes. 3. A sequence of histogenetic events occurred. The area of bone formation gradually expanded in the fibrous tissue area. 4. Expansion of the bone formation area was almost completed at 2 weeks. Most of the original marrow was transformed into thin trabeculae-forming areas, and hematopoiesis and sinusoidal capillaries formed in the new marrow. These conditions at 2 weeks were similarly maintained at 1 month. 5. At 3 months, the number of trabeculae, sinusoidal capillaries and hematopoietic area decreased, with the increase of adipose cells. 6. These results indicate that the area of fatty marrow where the hemorrhagic infiltration occurred was transformed into the bone formation area, and the marrow activates particularly high between the period of 2 weeks and 1 month.
Yamamura
M
M
Department of Fixed Prosthodontics, Faculty of Dentistry, Tokyo Medical and Dental University.
D000818:Animals; D001853:Bone Marrow / Q000473:pathology*; D004285:Dogs; D007568:Jaw / Q000473:pathology*; D006472:Oral Hemorrhage / Q000473:pathology*; D013997:Time Factors