Background: Regenerative periodontal therapy aims to predictably restore the tooth's supporting periodontal tissues and should result in formation of a new connective tissue attachment (i.e. new cementum with inserting periodontal ligament fibres) and new alveolar bone. Histologic evidence from preclinical models has demonstrated periodontal regeneration following treatment with barrier membranes, various types of grafting materials or a combination thereof. However, it is still not clear to what extent a combination of barrier membranes and grafting materials may additionally enhance the regeneration process compared with barrier membranes alone, grafting materials alone or open flap debridement.

Objectives: To review with a systematic approach all preclinical (i.e. animal) studies presenting histologic support for periodontal regeneration using the combination of barrier membranes and grafting materials.

Material and methods: Based on a focused question, an electronic and manual search was conducted for animal studies presenting histological data for the effect of the combined use of barrier membranes and grafting materials on the treatment of periodontal defects. A systematic approach was followed by two independent reviewers including eligibility criotateria for study inclusion, outcome measures determination, screening method, data extraction, data synthesis and drawing of conclusions.

Results: Ten papers completely fulfilling the inclusion criteria were selected. All relevant data from the selected papers were extracted and recorded in separate tables according to the types of periodontal defects treated (i.e. supra-alveolar defects, intrabony defects, furcation defects and fenestration defects) with the combination of barrier membranes and grafting materials. Most studies have demonstrated periodontal regeneration following the combination approach. Most studies demonstrated superior histologic healing following the combination of barrier membranes and grafting materials than following open flap debridement. Histologically superior healing following the combination of barrier membranes and grafting materials when compared with barrier membranes alone or grafting materials alone were only obtained in non-contained two wall intrabony and supraalveolar defects.

Conclusion: Within its limits the present analysis indicates that: (a) The combination of barrier membranes and grafting materials may result in histological evidence of periodontal regeneration, predominantly bone repair. (b) No additional benefits of combination treatments were detected in models of three wall intrabony, Class II furcation or fenestration defects. (c) In supra-alveolar and two wall intrabony (missing buccal wall) defect models of periodontal regeneration, the additional use of a grafting material gave superior histological results of bone repair to barrier membranes alone. (d) In one study using a supra-alveolar model, combined graft and barrier membrane gave a superior result to graft alone.