Animal Experimental Study Of The Orthodontic Tooth Movement In The Area Of Alveolar Bone Defect Repaired By GBR Technology

Objective:After application of guide bone regeneration technology (GBR), the alveolar bone critical-sized defect was repaired with different materials. Observing the osteogenesis and the orthodontic tooth movement, to discuss the feasibility of orthodontic tooth movement after the alveolar bone defect repaired.Methods:Thirty six New Zealand big white rabbits were randomly divided into A, B and C three groups, twelve in each group. Group A filled with PRP/Bio-Oss/Bio-Gide on bone defect; group B filled with Bio-Oss/Bio-Gide on bone defect; group C was the blank, as the control group. Through the general observation, X-ray observation, CBCT bone density testing, and histological observation, to evaluate the osteogenesis of the alveolar bone critical-sized defect, on the basis of the qualitative and quantitative analysis. Move the second molar towards the mesio-direction respectively in postoperative8weeks and12weeks. After8weeks under the strength, observing the teeth movement distance, through the X-ray observation, the CBCT bone density testing and histological observation, to evaluate the reconstruction on periodontal tissue and the bone defect area.Results:1. Osteogenesis observation in alveolar bone defect area;①X-ray shows:After12weeks, the image density of A-I was more homogeneous, the cortical bone was continuous; the image density of B-I was not homogeneous as A-I; the image density of C-I was higher on the edge of the bone defect, however, it was still pervious to light in the center.②CBCT bone density testing:Each postoperative time point:the bone mineral density of A-I and B-I was significantly higher than C-I (P<0.01); the bone mineral density of A-I was lower than B-I (P<0.05).③Histological observation:Each postoperative time point:the percentage of the new bone formation of bone defect area in A-I and B-I had significant difference at each time point (P<0.01). 3. Orthodontic teeth movement observation:①The orthodontic teeth movement distance: the group who began to inflict strength after8weeks:there was not significantly difference for the tooth movement distance between group A-II and group B-II (P>0.05); the group who began to inflict strength after12weeks:there was also not significantly difference for the tooth movement distance between group A-Ⅱ and group B-Ⅱ (P>0.05).③CBCT bone density testing:After16weeks and20weeks, there was significantly difference for bone density between and in group A-II and B-II (P<0.05).③Histological observation:the percentage of the new bone formation of bone defect area was different, group A-II was lager than group B-II (P<0.05). Periodontal membrane interface shows:periodontal ligament gap became narrowly in pressure side; periodontal ligament gap increased widely in tension side; bone grafts were located outside of the periodontal ligament, and there was obvious absorption for them at the pressure side of teeth.Conclusion:1. PRP/Bio-Oss/Bio-Gide has a better osteogenesis effect than Bio-Oss/Bio-Gide in the process of alveolar bone defect repairing in rabbit.2. PRP can promote the new bone formation and the degradation-absorption of Bio-Oss.3. After PRP/Bio-Oss/Bio-Gide and Bio-Oss/Bio-Gide repairing the defective areas for8ws, the teeth are able to move, and the distance and pattern of teeth movement has no difference between the two groups.