Experimental Study Of Polylactic Acid Membrane In The Repair Of Alveolar Bone Defects In Beagle Dogs

Objective: Experimental study of polylactic acid membrane in the repair of alveolar bone defects in Beagle dogs,and to compare it with the commercial collagen membrane.To provide experimental basis for further clinical use of domestic brand biofilm.Methods: 18 adult healthy beagles were randomly divided into 6 time nodes of 2,4,8,12,16 and 24 weeks,each time node was 3,male and female unlimited.The second and fourth premolars on the left side of the mandible and the third premolar on the right side of the mandible were extracted and healed for three months.In the extraction area,the flap was opened,and a box bone defect with a width of 8 mm in the proximal and distal directions,6 mm in the vertical direction and 4 mm in the buccal and lingual directions was made by drilling the ball into the extraction socket.Three kinds of filling materials were randomly filled,namely,artificial bone implant(G),artificial bone implant + medical collagen membrane(GC),artificial bone implant + Polylactic Acid Oral Barrier Membrane(GP).The effect of inducing bone regeneration was observed by self comparison.Three beagles were anesthetized at 6 time nodes of 2,4,8,12,16 and 24 weeks.The left and right mandibles of each dog were examined by X-ray and the image density was analyzed quantitatively.The mandible samples containing bone powder,Polylactic Acid Oral Barrier Membrane and medical collagen repair membrane were separated at each time node,fixed,dehydrated,embedded and sectioned,and observed under optical microscope.Through the X-ray and histopathological examination of all time nodes,the role of Polylactic Acid Oral Barrier Membrane in guiding tissue regeneration and repair was discussed from three aspects: the regeneration of new bone,the isolation of membrane materials and the degradation of membrane materials.Results:1.At 2,4,8,12 weeks after operation,the image density of the injured area in each experimental group was significantly lower than that in the normal area.New bone trabeculae were found in the defective area of each experimental group 16 and 24 weeks after operation.The integral density of each group decreased exponentially after bone defect filling operation.At the 2nd,4th,8th,16 th and 24 th week of operation,there was no significant difference between the two groups(P > 0.05).At 12 weeks after operation,the X-ray integral density of GP group was significantly higher than that of GC group(P =0.038,P < 0.05),and there was no significant difference between GC and GP groups(P >0.05).2.At the 2nd,4th,8th and 12 th week of filling materials,the scores of space maintenance characteristics of membrane materials in GP group were higher than those in GC group(P > 0.05),and there was no significant difference.At the 24 th week,the score of space maintenance characteristics of membrane materials in GP group was higher than that in GC group(P = 0.017,P < 0.05).During the experiment,the cumulative score of space maintenance characteristics of membrane materials in GP group was higher than that in GC group(P = 0.009,P < 0.01).3.At the 2nd,4th,8th,16 th and 24 th week of filling material,the proliferation score of bone tissue in the defect area of GP group was slightly higher than that of G group,but the difference was not statistically significant(P > 0.05).At the 2nd,12 th,16th and 24 th week,the proliferation score of bone tissue in the defect area of GP group was slightly higher than that of GC group,but the difference was not statistically significant(P > 0.05).There was no significant difference between GP group and GC group(P = 0.321,P > 0.05).There was a significant difference between GP group and G group(P = 0.044,P < 0.05).There was no significant difference between GC group and G group(P = 0.314,P > 0.05).Conclusion:1.Polylactic acid membrane has a reliable osteogenic effect in the repair of alveolar bone defects in beagle dogs.2.This study can provide evidence for the further clinical use of PLA.