Objectives: the study aimed to evaluate the histological effect of nanocrystalline hydroxyapatite mixed with parathyroid hormone on the healing of mandibular bone defect.
Material & Methods: The present study was conducted on 18 skeletally mature mongrel male dogs. The animals were randomly assigned (1:1)to one of the two groups (9 animals each) according to the treatment method: Study group where animal received PTH- Nanobone® mixture in a created osseous defects and control group where animal received Nanobone® solely within the defect. Three animals from each group were sacrificed at 3, 6 and 12 weeks postoperative. All groups were analyzed histological for the closure of the created osseous defect, the characteristics of the developed connective tissue, the nature of the formed osteoid matrix, the presence of acute or chronic inflammatory cells, and the type and progression of the healing process.
Results:
The histological examination showed significant difference between the 2 groups with better bone healing at Study group (PTH- Nanobone group). As the histological section Study group (PTH- Nanobone group) showed newly formed thin bone bridges of woven bone at 3 weeks postoperative while at 6weeks bone bridges of woven bone became thicker. At 12 weeks follow-up, both groups showed signs of healing although Study group (PTH- Nanobone group) a more lamellar and well organized bone is formed with newly haversian systems with wide osteons become evident.
Conclusion:
The results suggest that nanocrystalline hydroxyapatite mixed with parathyroid hormone encouraged the bone healing in critical-size calvarial defects