ABSTRACT
Objective:To observe the repair effect of nano hydroxyapatite/magnesium(nHA-Mg)porous composite material modified by poly lactic acid/glycolic acid copolymer(PLGA) on the jaw bone defect of rabbits,and to elucidate the mechanisms preliminary.Methods:The mandibular defect models of 10 mm×5 mm×1 mm in the 18 rabbits were established.Nine rabbits were selected and implanted with nHA-Mg composite materials modified by PLGA in the left as experimental group and the right as blank control group;the other nine were implanted with nHA-Mg in the left as positive control group and the right as blank control group.The rabbits were sacrificed at 4, 8, 12 weeks (respectively 3 of experimental group and positive control group every time)and the mandibular defect areas were intercepted and observed by imaging and histological examination;the sizes of the newborn trabecula area and residual materials in experimental group and positive control group were compared.Results:Compared with positive control group and blank control group, the percentage of newborn trabecula area of the rabbits in experimental group was increased (P0.05).The imaging results showed that the new bone formation can be observed in experimental group and better than positive control group and blank control group.The paraffin section results indicated that there were visible vascular tissue and newborn trabecula,the osteoblasts gathered around the bone trabecula;a lot of pits were located in the bone trabecula, and the pits contained osteocytes in experimental group.As the prolongation of time,thickened newborn trabecula, dense arrangement and trend of converting to lamellar bone were observed in experimental group.The hard tissue section results showed that the remaining amount of materials in experimental group was more than that in positive control group.Conclusion:nHA-Mg porous composite materials modified by PLGA can effectively reduce the rate of degradation in the body, promote osteogenesis and guide the bone regeneration.
ABSTRACT
Objective:To evaluate the effect of internal distraction osteogenesis in the treatment of complicated teeth-maxillofacial deformity.Methods:Clinical data of 1 0 cases with complicated teeth-maxillofacial deformity were analyzed retrospectively.In the first stage,the patients were operated by internal distraction osteogenesis.In the second stage,the distractor was removed after 3 to 6 months of consolidation period,followed by other operation for further occlusal reconstruction.Results:All the operations were per-formed as planned.The distraction distance was 7 -70 mm.The distraction process was smooth in all the cases.Occlusion was recon-structed and the deformity was corrected by following operation satisfactorily.Conclusion:Internal distraction osteogenesis is effective in the treatment of complicated teeth-maxillofacial deformity for further occlusal reconstruction and functional repair.