Repair of maxillary alveolar cleft defects with two different bioabsorbable implants: an experimental study in growing rabbits

Two different bioabsorbable implants and their ability to promote bone form ation in repair of experimental maxillary defects were investigated. A poly L/D-lactide mesh and a two-layer composite membrane consisting of a film m ade of a copolymer of L-lactic acid and epsilon -caprolactone combined with the polylactide mesh were used as implants. A standard alveolar defect was made bilaterally in the maxilla and filled with autogenous bone grafts in 30 growing rabbits. Follow-up was 10 weeks. Three experimental groups were formed. (1) defect covered with polylactide mesh versus control defect with out implant, (2) defect covered with composite membrane versus control defe ct, and (3) defect covered with membrane on one side and with mesh on the o ther. Radiological, histological and histomorphometric evaluations were per formed. In histomorphometric measurements, a significantly larger quantity of bone was obsen ed in the composite membrane-covered defects compared wit h the polylactide mesh-covered and the control defects. Osteogenic activity was also highest in the membrane-covered defects. The bioabsorbable compos ite membrane appears to promote healing of experimental maxillary alveolar defects in accordance with the principle of guided tissue regeneration. The polylactide mesh alone was less potent in promoting healing of the defect, although an enhancing effect on osteogenic activity was observed.