Guided bone regeneration with biphasic calcium phosphate - a pilot study in rats

Introduction: The experimental membrane of polyethylene glycol (PEG) intends to overcome the disadvantages of other membranes. Several publications proved PEG's: biocompatibility, occlusive function and ability to prevent collapse. Biphasic calcium phosphate (BCP) contains hydroxyapatite and β-tricalcium phosphate. Objectives: Evaluate the regenerative effect of BCP covered with a PEG membrane and compare the results with the regeneration of defects covered only with the PEG membrane. Materials and Methods: Two parietal defects with a 5mm diameter were created in seven Wistar rats. The control defect (left parietal bone) was covered with PEG membrane and the test defect (right parietal bone) was filled with BCP and covered with PEG membrane. After two months, histologic and histomorphometric analysis were made. The statistical analysis was made with a 95% confidence interval. Results: The test defects had a percentage of new bone formation area of 61.7%±14.6% and the control defects obtained 57.3%±21.8%. The result was not statistically significant (p=0.539). BCP had a low number of particles incorporated into the neoformed bone. The BCP and PEG membrane remained intact after 2 months. Conclusions: There were no statistically significant differences between the groups. BCP did not exhibit osteoconductive properties but sustained PEG membrane. The PEG membrane had a fast and easy application, fixed itself, proved to be biocompatible and occlusive. Clinical Implications: Guided bone regeneration with BCP may not obtain the desired osteoconductive effect. The PEG hydrogel may reduce surgical time. Keywords: Guided bone regeneration, Biphasic calcium phosphate, Polyethylene glycol, Wistar, Graft, Membrane