LONG-TERM EVALUATION OF THE USE OF CORALLINE HYDROXYAPATITE IN ORTHOGNATHIC SURGERY

Purpose: This prospective study was designed to evaluate the long-term clinical and radiographic results of porous block hydroxyapatite (PBH A) used as a synthetic bone graft in orthognathic surgery and craniofa cial augmentation. Patients and Materials: A total of 245 consecutive patients were treated initially. Inclusion criteria for this study inc luded a minimum clinical and radiographic follow-up of 5 years. In add ition, all patients with known implant failures were included regardle ss of whether they met the study criteria. There were 111 patients tha t met the criteria for inclusion in this study. All patients had under gone orthognathic surgery with rigid fixation and had had inlay or onl ay PBHA implants placed. Ninety-six percent of the implants were place d through an intraoral approach. Long-term postoperative radiographs w ere visually compared with immediate postoperative radiographs for imp lant position, stability, resorption, and other significant radiograph ic changes. The clinical examination evaluated for signs and symptoms of infection, wound dehiscence, implant exposure, implant displacement , changes in the overlying mucosa, and development of oronasal or oroa ntral fistulae. Results: Four hundred seventy-one implants were placed : 403 in the maxilla, 44 in the mandible, and 24 in the periorbital re gion. There were 289 implants placed in direct communication with the maxillary sinus. The average follow-up time was 7.2 years (range, 5.0 to 10.3 years). Twenty-three implants (4.9%) were removed during the e valuation period. Lateral maxillary wall grafting had 95.7% success, w ith nine implants being lost in three patients. One chin implant was r emoved because of dissatisfaction with the aesthetics. Seven (14%) mid palatal implants used for maxillary expansion were lost, primarily bec ause of exposure of the implant to the oral or nasal cavity at the tim e of surgery. When PBHA was used for alveolar cleft grafting, there wa s a 100% failure rate. Conclusion: The use of PBHA as a bone graft sub stitute in orthognathic surgery and for facial augmentation showed a h igh percentage of success and efficacy. However, adequate soft tissue coverage in the nasal floor and on the palate are paramount for succes s of midpalatal implants. PBHA should not be used for alveolar cleft g rafting. Rigid fixation for inlay implants in the maxilla is important to provide stress shielding of the material and minimize micromovemen t during the initial healing phase.