Objectives : To evaluate, in a rabbit model, the capacity of different polymer–bioceramic composite materials to regenerate a critical sized calvarial defect.

Methods : In this paper various synthetic polylactic and polylactic–bioceramic composite scaffolds with two different forms were applied to critical sized bone defects (15 mm × 15 mm) in the frontal bone of 42 adult New Zealand white rabbits to assess its effect on bone regeneration. The rabbits were divided into seven groups with six animals each; Group 1: control, Group 2: polylactic acid polymer plate completely covering the bone defect, Group 3: polylactic acid polymer plate partially covering the bone defect, Group 4: polylactic acid polymer plate coated with bioglass particles completely covering the bone defect, Group 5: polylactic acid polymer plate coated with bioglass particles partially covering the bone defect, Group 6: polylactic acid polymer plate coated with bovine bone derivated hydroxyapatite particles completely covering the bone defect, Group 7: polylactic acid polymer plate coated with bovine bone derivated hydroxyapatite particles partially covering the bone defect. The animals were sacrified at 24 weeks. Bone healing was assessed clinically, radiographically, and by histomorphometry. Histomorphometric analysis was preformed. The following parameters were measured: total area of the defect, percentage of new bone, residual biomaterial and conective tissue. A Anova test was used to elucidate the significance of the individuals biomaterials compared with each other.

Results : The control group had 23.67% new bone fill. The group of polylactic acid polymer plate completely covering the bone defect had 35.16% new bone formation. The group of polylactic acid polymer plate partially covering the bone defect had 27.80% new bone fill. Polylactic–bioceramic composite did not improve the response obtained with the polylactic plate.

Conclusions : The only effect seems to improve bone regeneration in critical sized defect in rabbit skull is complete coverage of the defect.