Study Of Orthodontic Tooth Movement Into Alveolar Defect Regenerated By Use Of Bone Marrow Mesenchymal Stem Cells And β-TCP Scaffold In Rabbit

Purpose: To explore the effect of regenerated bone in rabbit alveolar defect with bone marrow mesenchymal stem cells(BMSCs)and porous granulated beta-tricalcium phosphate(β-TCP)scaffolds on subsequent orthodontic tooth movement(OTM).Methods: New Zealand rabbits were used to establish the bilateral mandibular defective alveolar bone model by extracting the mandibular first molars and expanding the sockets.The right mandibular alveolar defects were filled with a construct of b-TCP scaffolds combined with BMSCs as experiment sides.The left alveolar defects were repaired by b-TCP scaffolds alone as control sides.Eight weeks later,6 rabbits were sacrificed to evaluate osteogenesis effect by method of hard tissue slicing and Van Gieson’s staining.The other rabbits were loaded orthodontic force to move the bilateral second molars forward for 4 weeks.6 rabbits of each group were sacrificed at 1,2,3,and 4 week after OTM.The distance of OTM was measured,and the status of periodontal tissues was observed by HE staining.The number of osteoclasts on the compression side of tooth was counted by tartrate-resistant acid phosphatase histochemistry,and the expression of BMP-2 on the tension of tooth was analyzed immunohistochemical method.T test was used to compare the differences between the groups.Results: After 8 weeks of bone graft,the osteogenesis effect of the experiment group is better than the control group.The OTM distance in experimental area was higher than that in control area.At 2,3 and 4 week of OTM,both the number of osteoclasts and the expression of BMP-2 in experimental group were significantly higher than those in control group.Conclusions: 1.A tissue-engineered complex with b-TCP scaffolds and BMSCs could well repair the alveolar bone defect.2.Orthodontic treatment could be performed after the repair of alveolar defects by a tissue-engineered complex with b-TCP scaffolds and BMSCs and by b-TCP scaffolds alone.3.When the adjacent tooth moved into regenerated area repaired by a tissue-engineered complex we made,the new periodontal tissue had an active response,promoting to accelerate the tooth movement.