The Effect Of Osteoporosis On The Healing Of Tooth Extraction

Objectives:To investigated the effect of osteoporosis on the healing of tooth extraction by using histology and bone histomorphometry. In order to provide some experimental data for clinical therapy. Methods and materials:Thirty-eight 5-months, female, New Zeland rabbits used in this study, they were devided into two group randomly: the experimental group(OVX group) and the control group(Sham-OVX group). Each group had 19 rabbits. At the beginning, the weight of all the animals were recorded. The OVX group had bilateral ovariectomy and the Sham-OVX group underwent sham ovariectomy. After surgery, the OVX group was fed on a 0.15% low-calcium diet. The 2nd months postoperation, the weight of all the animals were recorded again and one rabbit in each group was sacrificed to be prepared for histologic examination. The OVX group were confirmed to be osteoporosis by histologic study. The 3rd months postoperatively, under anesthesia the maxillary first molars were extracted and all the animals were fed on the normal diet. At 2nd,4th,8th weeks after extraction ,the rabbits were killed respectively. Each group included six rabbits.The maxillae were dissected, and fixed immediately. The sampals were prepared for hematoxylin and eosin (HE) stain and observed histologically. Simultaneously histomorphometry examination was done. The parameters of histomorphometry were: the percent of trabercular area (Tb.Ar%),trabercular circumference (Tb.Cir), trabercular average width (Tb.Wi), trabercula maximum diameter (Tb.D-Max), trabercular minimum diameter(Tb.D-Min), trabercular number(Tb.N), osteoblasic number(OB.N), osteoclastic number (OC N). Each section were selected eight fields of vision.The acquired data and the weight of the two group animals gained during the two month were analyzed for statistical significance by SPSS 10.0 software. Result:1.Histologic examination:At the 2nd weeks after extraction, in the OVX group it was more obvious that fibroblastic proliferaton and new bone formed by fibrocytes compared with the sham-OVXgroup. Osteocyte and osteoblast arranged densely. The trabeculae were more delicate than those in the Sham-OVX group. At the 4th weeks after extraction ,in the OVX group, the less and thiner traberculae arranged in disorder compared with the sham-OVXgroup. Osteoblasts and Howship resorption lacunae were abserved. Mesenchymae trended to ossify apparently,and blood capillaries were abundant. At the 8th weeks after extraction, in the OVX group bone resorption and bone formation more actively than those inSham-OVX group.The thin traberculae arranged in irregularity compared with the sham-OVX group. 2. Histomorphometric examination on bone: The percent of trabercular area(Tb.Ar%), the trabercular circumference (Tb.Cir), the trabercular average width (Tb.Wi) in OVX group were significant lower than those in Sham-OVX group at the 2nd ,4th ,8th weeks after extraction between the two groups (P<0.01) . The percent of trabercular area(Tb.Ar%), the trabercular circumference (Tb.Cir), the trabercular average width (Tb.Wi), the trabercular maximum diameter(Tb.D-Max), the trabercular minimum diameter (Tb.D-Min) were significant difference in different time at the 2nd,4th,8th weeks after extraction in each group. Between the two groups the trabercula maximum diameter (Tb.D-Max), the trabercular minimum diamete (Tb.D-Min) in OVX group were significant lower than in Sham-OVX group at the 2nd,4th,8th weeks after extraction (P<0.05) . Between the two groups the osteoblasic number (OB.N), the osteoclastic number (OC.N) in OVX group were significant higher than in Sham-OVX group at the 2nd 4th 8th weeks after extraction (P<0.05). The osteoblasic number (OB.N), the osteoclastic number (OC .N)was significant difference at 2nd,4th,8th weeks after extraction in each group. Between the groups, the trabercular number(Tb.N) had no significant difference at the 2nd,4th,8th weeks after extraction (P>0.05) The