Alveolar ridge augmentation with collagen tubes containing bone and hydroxylapatite.

The use of collagen tube containers with implants of an autogenous bone and particulate hydroxylapatite composite is reported. The tubes were used to shape the mixture and to facilitate its implantation in cases of severe mandibular resorption. Following a minimum of 60 months after implant placement and a minimum of 48 months of denture wear, the implant and overall prosthodontic success were rated favorably by the patient and the prostodontist. Individual implants were evaluated with polarized and fluorescent light microscopy and with microradiography. While the clinical results were good, the microscopic evaluation showed the amount of bone present within the implant to be variable.     

Alveolar ridge augmentation in rats by combined hydroxylapatite and osteoinductive material.

The purpose of this study was to examine if increased bony ingrowth developed when hydroxylapatite was implanted together with an osteoinductive substrate. Dense hydroxylapatite granules (HA) (Calcitite, Calcitek, San Diego, CA, USA) were mixed with equal volumes of allogenic, demineralized, lyophilized dentin or bone and implanted subperiosteally for alveolar ridge augmentation purposes and heterotopically in the abdominal muscles in rats. Light microscopic evaluation revealed that HA was surrounded by fibrous connective tissue containing foreign body giant cells and it had neither an osteoinductive nor an osteoconductive effect. The newly formed bone induced from the implanted allogenic, demineralized, lyophilized dentin or bone was never found in close contact with the HA and did not incorporate the implant.     

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.     

Alveolar ridge augmentation in rats by combined hydroxylapatite and osteoinductive material

Abstract— The purpose of this study was to examine if increased bony ingrowth developed when hydroxylapatite was implanted together with an osteoinductive substrate. Dense hydroxylapatite granules (HA) (Calcitite, Calcitek, San Diego, CA, USA) were mixed with equal volumes of allogenic, demineralized, lyophilized dentin or bone and implanted subperiosteally for alveolar ridge augmentation purposes and heterotopically in the abdominal muscles in rats. Light microscopic evaluation revealed that HA was surrounded by fibrous connective tissue containing foreign body giant cells and it had neither an osteoinductive nor an osteoconductive effect. The newly formed bone induced from the implanted allogenic, demineralized, lyophilized dentin or bone was never found in close contact with the HA and did not incorporate the implant.     

Alveolar ridge augmentation with hydroxylapatite using fibrin sealant for fixation. Part I: An experimental study.

Histological studies in animals have shown that fibrin sealant can be employed as a resorbable, biological binding agent for fixation of initially mouldable hydroxylapatite (HA) implants. Mixing HA granules with a 2 component fibrin sealant from which thrombin solution has been diluted to 1 IU/ml provides a simple method for obtaining mouldable implants. During insertion of the HA granules, the sealant prevents dislocation and migration, and on solidification, the moulded implant securely retains its shape and position until connective tissue ingrowth is complete. The use of polygonal granules permits a constant implant contour from the very beginning.     

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.     

Alveolar ridge maintenance with hydroxylapatite ceramic cones in humans

The efficacy of solid cones of hydroxylapatite ceramic implanted in fresh extraction sockets for the preservation of alveolar bone was evaluated. Ten experimental subjects (70 implants) and eight control subjects (63 extractions) were treated. After extraction, hydroxylapatite ceramic cones were inserted into the sockets at least 1 mm below the alveolar crest in the experimental group. Alveolar ridge resorption was measured on lateral cephalometric radiographs, and statistical analysis was performed. The follow-up periods ranged from 12 to 24 months (mean, 20.6 months). Thirty-seven of the 70 hydroxylapatite ceramic cone implants (53%) became exposed, and 19 cones (27%) had to be removed. It was concluded that hydroxylapatite ceramic cone implants placed in fresh extraction sockets do not significantly preserve alveolar bone.     

Alveolar ridge augmentation with tricalcium phosphate ceramic

Tricalcium phosphate ceramic, with 50% porosity and 400 to 500 micrometer pore diameter, was used to augment the edentulous alveolar ridge of 10 adult mongrel dogs. The implants were evaluated histologically at different time intervals (7, 30, 90, 180, and 360 days). Preoperative and postoperative blood chemistry studies were also evaluated. The results showed that, other than for the expected acute nonspecific inflammatory response due to the surgery, the material was well tolerated by the tissues and was nontoxic. Bone and soft tissues grew into the pores, thereby creating an excellent biomechanical bond between the ceramic implant and surrounding structures. Preoperative and postoperative blood chemistry studies demonstrated no significant change.     

Alveolar ridge augmentation using membranes

Successful augmentation of compromised ridges using membranes requires correct diagnosis and careful case selection. The goals of the reconstruction should be identified before surgery. The timing and application of membranes and selecting the type of bone graft specific for each site are important. The technique requires clinical experience in flap design and mobilization, trimming, shaping and stabilizing the membrane, and suturing. Careful postoperative management of forces on the alveolar ridge from removable appliances is required.     

Localized ridge augmentation with hydroxylapatite: report of case

Evaluation of the nonresorbable particulate form of hydroxylapatite for localized ridge augmentation has been described. The surgical technique using this material is simple and effective, and produces an improved ridge base for pontic function. Six-month postoperative examination showed the area to be clinically stable with significant improvement of cosmetic appearance. The augmented area of the ridge was convex and had improved contour in width and height.     

Alveolar ridge augmentation in rats by Bio-Oss.

The purpose of the study was to examine if Bio-Oss initiated osteoinduction or osteoconduction when implanted into rats. Sintered and unsintered granules of the anorganic bovine bone Bio-Oss was implanted subperiosteally for alveolar ridge augmentation purposes and heterotopically in the abdominal muscles of rats. Light microscopic evaluation revealed no osteoinduction or osteoconduction in connection with sintered or unsintered Bio-Oss. A foreign body reaction was observed around both forms.     

Alveolar ridge augmentation by distraction osteogenesis

Distraction osteogenesis is an alternative method for reconstructing atrophic alveolar bone. Fourteen patients underwent vertical alveolar distraction by the LEAD SYSTEM-Endosseous Alveolar Distraction System (Stryker Leibinger, Kalamazoo, MI). An alveolar segmental osteotomy was carried out and the vertical distraction device was mounted. In patients with an extensive alveolar defect, two distraction devices were placed in order to better control the vector of elongation in both bone edges. The distraction was started on the fourth postoperative day at a rate of 0.8 mm/day for 10-16 days, followed by a consolidation period of 60 days. Vertical distraction osteogenesis (VDO) was completed successfully in all patients with segment lengths in the range of 8 to 13 mm and with an average of 10.3 mm. Subsequently, the devices were removed and 23 threaded titanium dental implants were placed for osteointegration. Earlier mineralization in the vertically distracted area was seen radiographically during the consolidation period. In a follow up of 6-20 months after the distraction, 22 implants were successfully osteointegrated while one implant failed due to improper distracted segment stability. As a result of alveolar distraction, a segment of mature bone was transported vertically in order to lengthen the crest for better implant anchorage, either for aesthetic purposes or for functional prosthetic requirements. The main advantages of VDO are: (1) augmentation of alveolar bone height with new bone formation and simultaneous expansion of the soft tissues; (2) no bone harvesting is necessary; (3) the technique has a lower morbidity rate compared with conventional techniques; (4) it makes the insertion of longer dental implants feasible.