Radiographic and histomorphometric evaluation of an ovine forestomach matrix combined with Bio-Oss bone graft in a sheep tooth extraction model
Alveolar ridge is a tooth dependent structure. Following tooth extraction, volume reduction and dimensional changes take place. These changes often make it difficult to replace the missing teeth due to a lack of bony support and compromised aesthetics. To minimise and overcome these issues various alveolar ridge preservation techniques (ARP) have been developed. One of the more commonly used techniques is treatment with bone replacement graft material (BRG) covered by a barrier membrane. One of the more frequently used BRG materials in Australasia is Bio-Oss® (Geislich, Switzerland) in combination with Bio-Gide® (Geistlich, Switzerland) membrane. This project sought to compare established membrane Bio-Gide® to Ovine Forestomach Matrix (OFM, Aroa Biosurgery Limited, New Zealand). Objectives To conduct a systematic review and assess the existing evidence for outcomes of bone xenograft in combination with resorbable collagen membranes for alveolar ridge preservation in randomised clinical trials in non-human and human experimental models. To analyse healing outcomes and compare OFM to Bio-Gide® in a pre-clinical and histological equivalency trial; and to test non-inferiority between these two membranes. Materials and methods Thirty sheep underwent the extraction of three left mandibular premolars. Using Latin-square allocation three treatment groups were assigned. Treatment A (OFM + Bio-Oss®), treatment B (Bio-Gide® + Bio-Oss®, positive control) and treatment C (naturally healed socket, negative control). Ten animals were allocated to each of three healing time points of 4-, 8- and 16-weeks. After the allocated healing time the animals were euthanised, mandibles dissected, and extraction sockets resin embedded for descriptive histology, radiographic and histomorphometric analysis. Results At four weeks, all sockets mostly comprised connective tissue. The sites grafted with BRG, regardless of membrane used, showed small projections of woven bone that extended towards the lumen of the socket and surrounded the Bio-Oss® particles. At eight weeks, the control sockets were still predominantly filled with connective tissue, while sockets with BRG formed a hard tissue bridge composed of woven bone between the buccal and lingual cortical plates. At 16-weeks of healing, complete bridging between socket margins was evident in all three groups. Histomorphometric analysis demonstrated significant new bone increase over time in OFM group (p<0.009). At 4-weeks the Bio-Gide® group had more residual bone graft compared to the OFM group, 13.92±10.64% and 5.45±6.59% respectively (p=0.005). However, this difference was not observed at 8- or 16-weeks. Both grafted groups have significantly less connective tissue compared to the ungrafted control group at 4-weeks (p<0.045). Radiographic and histology images of the same sites were matched well. Conclusion This study found that OFM demonstrated equivalent outcomes to Bio-Gide® membrane in terms of graft retention and osteogenesis in an ovine tooth extraction model.
Advisor: Duncan, Warwick; Coates, Dawn; Milne, Trudy
Degree Name: Doctor of Clinical Dentistry
Degree Discipline: Oral Sciences
Publisher: University of Otago
Keywords: alveolar; ridge; preservation; animal; model; ovine; collagen; membrane
Research Type: Thesis