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Delayed versus immediate reconstruction of mandibular segmental defects using recombinant human bone morphogenetic
Khaled A Hussein1, Ibrahim E Zakhary, Dana Hailat
1Oral and Dental Research Division, Department of Surgery and Medicine, National Research Center, Cairo, Egypt.
Summary
Immediate reconstruction using recombinant human bone morphogenetic protein 2 (rhBMP2)/absorbable collagen sponge (ACS) significantly improved mandibular defect healing in dogs compared to delayed application. Delaying rhBMP2/ACS attenuated bone regeneration quality and quantity.
Area of Science:
- Oral and Maxillofacial Surgery
- Regenerative Medicine
- Biomaterials Science
Background:
- Mandibular segmental defects pose significant reconstruction challenges.
- Recombinant human bone morphogenetic protein 2 (rhBMP2) on an absorbable collagen sponge (ACS) is a promising bone graft substitute.
- The optimal timing for rhBMP2/ACS application in mandibular reconstruction remains under investigation.
Purpose of the Study:
- To compare the efficacy of immediate versus delayed application of rhBMP2/ACS for mandibular segmental defect reconstruction.
- To evaluate the impact of reconstruction timing on bone formation quantity and quality in a canine model.
Main Methods:
- A 35-mm osteoperiosteal segmental defect was created in the mandible of 11 dogs.
- Dogs were randomized into immediate reconstruction (Group 1) or delayed reconstruction (Group 2, 4 weeks post-defect creation) with rhBMP2/ACS.
- Bone regeneration was assessed clinically, radiographically, and histomorphometrically 12 weeks post-application, including bone mineral density and microhardness testing.
Main Results:
- Immediate reconstruction (Group 1) resulted in significantly greater bone area (52.4% vs 36.6%) and defect filling (56.3% vs 38.5%) compared to delayed reconstruction (Group 2).
- Group 1 demonstrated significantly higher Vickers microhardness (20.3 μHV vs 13.2 μHV), indicating improved bone quality.
- While 83.3% of Group 1 dogs achieved successful regeneration, none in Group 2 showed complete successful regeneration.
Conclusions:
- Immediate application of rhBMP2/ACS is superior for mandibular segmental defect reconstruction in a canine model.
- Delaying rhBMP2/ACS application for 4 weeks significantly impairs both the quantity and quality of regenerated bone.
- These findings support prompt rhBMP2/ACS use for optimal outcomes in mandibular reconstruction.
