Background and objective : We have reported that HAp/agarose composite gel (HAp gel) is useful as a bone grafting material for bone defects. We previously investigated the biological behaviour of this material in an animal model and confirmed its potential as a bone substitute by several kinds of analyzes. Furthermore, we performed biological safety studies in accordance with the ISO 10993. To evaluate the biological behaviour of HAp gel and confirm that this material is promptly absorbs and is replaced by bone in jaw defects, with no adverse events clinically.
Methods : HAp gel disks were prepared by an alternate immersion technique, homogenized, transferred to a 1-mL syringe. HAp gel alone or mixed with autologous bone was filled into the jaw defect. Candidate patients had the following conditions: bone defects after the extirpation of jaw cysts, alveolar clefts associated with cleft lip and palate, and insufficient bone volume for dental implant placement. Osteogenesis was evaluated radiographically before and 1, 3, and 6 months after operation. The presence or absence of postoperative infection, prolonged inflammation, and inadequate wound healing was also evaluated.
Results : In all 16 patients, bone regeneration was confirmed 3 month postoperatively at the most apical region of the defect. No patient had postoperative infection, prolonged inflammation, or inadequate wound healing.
Conclusions : Evaluation of the characteristics of regenerated bone, such as quality, density, and hardness, is a topic for future studies. However, in patients who underwent bone grafting to the alveolar cleft, a sufficient quantity of bone was obtained by filling the defect with a mixture of bone obtained from the chin and HAp gel. This technique minimized surgical invasion in children and shortened the hospital stay. The indication range will be extended in the future.
Key words: bone regenerative material; hydroxyapatite; agarose gel