James H. Quinn

Alveolar ridge augmentation using nonresorbable hydroxylapatite with or without autogenous cancellous bone.

A four-year prospective evaluation of the use of nonresorbable, particulate hydroxylapatite (HA) to augment deficient alveolar ridges was performed. The material was used alone and in combination with finely crushed autogenous cancellous bone. Implants were delivered subperiosteally by syringe injection, usually using local anesthesia for Class I to Class III ridges and general anesthesia for Class III and Class IV ridges. The improved ridge height and width were stable. Postoperative resorption with significant loss of ridge height, frequently seen with rib and iliac crest onlayed grafts, was not observed with HA augmentation. Permanent denture construction began as early as three weeks postoperatively and by four to six weeks if HA was combined with autogenous cancellous bone. It was possible to place mandibular staple implants simultaneously or following HA augmentation. Visor osteotomy techniques were improved by use of HA to produce a wider, more convex stable ridge. Although skin, mucosa, or dermal vestibuloplasties were performed as early as three months postoperatively in a small number of patients, there appeared to be a lesser need for vestibuloplasty after HA augmentation than after onlay bone grafting. In addition, prosthodontists performed fewer denture relines after HA augmentation than after onlay bone grafts. The authors believe the most significant factor accounting for these observations is the firm, nonmobile mucosal base resulting from augmentation with HA. The resultant stable, soft tissue base and improved ridge height and contour have contributed to a comfortable, retentive, stable denture for these patients. The prosthetic and surgical procedures are easier to perform and have produced superior, more permanent results than onlay bone grafts and alloplasts. Preliminary studies also point to exciting possibilities for use of HA as a bone substitute/marrow extender in maxillary and mandibular defects, cysts, and clefts and in osteotomies for orthognathic surgery.

Hydroxylapatite alveolar ridge reconstruction: Clinical experiences, complications, and technical modifications

Results of the reconstruction of 228 deficient alveolar ridges (208 patients) using hydroxylapatite with or without autogenous cancellous bone over a six-year period are reported. Complications included erosion, mental nerve neuropathy, migration and displacement of particles, overfill, and loose material. Modified techniques are presented that minimize the occurrence of these complications in Class III and IV ridge-deficient patients.

Alveolar ridge maintenance with solid nonporous hydroxylapatite root implants

Animal studies were carried out to determine a simple technique of implantation of nonresorbable polycrystalline hydroxylapatite solid root forms and the biocompatibility of the material placed in fresh extraction sockets. An appropriately shaped root form was evaluated, and alveolar bone preservation was investigated in dogs and primates. It was found that bone and soft tissue would migrate across the HA root implant when placed 2 to 3 mm below the alveolar bone crest without soft-tissue closure. It was not necessary to use roots that fit the socket from the apex to the alveolar crest. An average of 2 mm more alveolar bone was preserved in fresh extraction sites as compared to control sites. The results of the animal studies indicated the appropriateness of a clinical trial in human beings.

Arthroscopic management of temporomandibular joint disc perforations and associated advanced chondromalacia by discoplasty and abrasion arthroplasty: A supplemental report

PURPOSE This article describes the results of treating temporomandibular joint (TMJ) articular disc perforation and advanced chondromalacia arthroscopically by the use of discoplasty and abrasion arthroplasty. PATIENTS AND METHODS Forty-four joints were treated in 25 patients (23 females and 2 males). Twenty-nine disc perforations were present, 24 joints had grade III chondromalacia (fibrillated cartilage), and 14 joints had grade IV chondromalacia (exposed bone). Surgical procedures included 14 abrasion arthroplasties and 24 motorized shavings or holmium laser vaporizations. Holmium laser discoplasty with mobilization was used in 29 joints. Patients were followed-up for an average of 40.8 months (11 to 74 months). RESULTS Preoperative pain on the visual analog scale (VAS) (1 to 10 cm) ranged from 5 to 10 cm, with an average of 7.4 cm. Postoperatively, nine patients had no pain and 16 patients had an average VAS of 2.7 cm (range, 1 to 5 cm). Preoperatively, 30 joints had clicking, and 14 joints had crepitation. Postoperatively, 25 joints had no noise, 12 joints had slight intermittent clicking, and seven joints had crepitation. The preoperative range of motion averaged 29.7 mm. Postoperatively, the range of motion averaged 37.7 mm (range, 33 to 42 mm). All patients could masticate a regular diet except hard food after an average of 40.8 months (11 to 74 months). CONCLUSIONS These findings seem to justify the arthroscopic surgical procedures of discoplasty for disc perforations, motorized shaving, or holmium laser vaporization of grade III chondromalacia, and abrasion arthroplasty for bone exposure. The results also question the need for discectomy in the treatment of disc perforation.

HYDROXYLAPATITE AUGMENTATION OF ATROPHIC ALVEOLAR RIDGE.

Publisher Summary This chapter discusses the hydroxylapatite augmentation of atrophic alveolar ridge. Hydroxylapatite (HA), a highly biocompatible, osteoconductive calcium phosphate material has provided a permanent support matrix for the deposition of fibrous tissue and bone by direct chemical bonding mechanisms. In some of the class III and IV ridge deficiency patients, 12–20 grams of HA mixed with finely crushed autogenous cancellous iliac bone was used to provide increased strength to the severely atrophic alveolar ridges. Surgical technique involved subperiosteal pocket tunneling through vertical mucoperiosteal incisions with or without a blind submucosal vestibuloplasty. Injection of HA into these pockets was done with a variety of modified plastic syringes. Solidification of HA generally occurred by the fourth to sixth postoperative week permitting impressions for denture construction. Skin and mucosal graft vestibuloplasty, if needed to increase sulcus depth after hydroxylapatite augmentation, was usually possible after two months because of the intense fibrous tissue infiltration between HA particles. In most patients augmentation of alveolar deficient ridges with HA has resulted in a permanent improved ridge height and convex contour. The overlying soft tissue mucosa is nonmobile except in severe ridge deficiencies where post operative vestibuloplasties are required.