The International Journal of Oral & Maxillofacial Implants, 04/1994

This study evaluated the use of autogenous bone grafts for the augmentation of small bone defects adjacent to implants placed into immediate extraction sockets. Fifty-four consecutively placed implants were evaluated in 30 patients (15 men and 15 women). Autogenous bone chips were harvested from bony ledges and protuberances adjacent to the extraction sites. Implants were placed entirely within the alveoli. Defect height was measured from the top of the implant cylinder to the base of the defect; defect width was measured from the top of the cover screw to the buccal crest of the alveolar bone. For buccal dehiscences, defect height and the number of exposed threads were recorded. Autogenous grafts were placed into all defects adjacent to implants. At second-stage surgery, there was an average of 5.4 mm change in defect depth (mean residual depth 0.3 mm) for implants placed entirely within the alveoli. The average change in defect depth for sites with buccal dehiscences was 4.7 mm (mean residual depth 0.6 mm). Changes in defect depth for both groups was statistically significant (P .001). Changes in thread exposure for the dehiscence group was statistically significant (P .001); the average change in thread exposure was 3.7 threads. Similarly, defect width was statistically improved for both groups. To date, 50 implants have been loaded with no loss of implants. The results of this study indicate that localized bone defects adjacent to implants placed into immediate extraction sockets and grafted with autogenous bone will heal with clinically and statistically significant amounts of bone. Keywords: autogenous bone grafts, bone protuberances, harvesting bone, immediate implant placement

Tissue responses to high-velocity flame-sprayed hydroxyapatite-coated titanium (AFC) and noncoated titanium alloy (Ti) implants were compared histologically and histomorphometrically. The percent of implant-bone contact of the AFC implants was higher than that of the Ti implants at each examination. The alveolar bone level was better maintained around the AFC implants than around the Ti implants. Some resorption of coated HA occurred on the bone-free surface of the cortical bone area and medullary cavity. These results indicate that coating with HA may speed early direct bone contact on the implant surface, but the resorption of coated HA occurs to some degree, even with an improved method. Keywords: high-velocity flame-spraying, hydroxyapatite, titanium

A photoelastic analysis was made to evaluate the stress patterns generated around implants with passive and nonpassive fitting frameworks. Five Brånemark implants were placed on a photoelastic analog of a human mandible. The frameworks were analyzed by photographing the stress fringes that were generated when the framework was tightened with gold screws to a torque of 10 Ncm on the abutments. The tightening of the nonpassive framework demonstrated significant stress buildup around the implants, whereas the sectioned and soldered passive framework showed no stress fringes around the implants after being tightened to the abutments. Keywords: fixed implant prosthesis, passivity, photoelastic analysis

Twenty-four patients confronted with different teeth loadings revealed the suprathreshold discrimination sensitivity of teeth and endosseous implants. Magnitude differences between loads applied to implants and loads applied to natural teeth were detected with the same accuracy in both cases. Present results agree with previous investigations employing other psychophysical methods. This strengthens the view that remote mechanoreceptors are responsible for suprathreshold touch sensitivity of both teeth and implants. Keywords: difference threshold, endosseous implants, mechanoreceptor, quantitative mechanoperception

This pilot study was done to evaluate the potential of the different cells of the forming tooth bud to induce formation of dental hard tissues and periodontal ligament around titanium implants. Deciduous premolar teeth were extracted in a 3/-month-old Landrace pig 1 month before implant placement. Four implants were placed in a pig's mandible near the tooth buds. A wide artificial bone defect was created around one of the implants; all implants were covered with Gore-Tex membranes. After 3 months, the animal was sacrificed, and the implants were retrieved and studied with the cutting-grinding system. Histologic analysis showed that all implants were covered by a mineralized tissue with a histologic appearance similar to cementum and separated from the bone by a periodontal-like space filled by collagen fibers. Keywords: cementum, periodontal ligament, titanium implants

Several implant systems have been introduced with material properties and design that emulate the original Brånemark system. A comparison of surface microstructure and the element composition of screw-type titanium dental implants from four different manufacturers [Nobelpharma (B), Swede-Vent (C), 3i (I), and Osseodent (O)] showed no substantial qualitative differences as regards chemical composition. At the ultrastructural level, the surface topographies of the B, O, and I implants were essentially similar, whereas the C implant differed from the others in having a more irregular surface. In a clinical pilot study, a direct comparison of the success rate and marginal bone level of three of these implant systems (B, I, and O, using the Brånemark system as a reference) was performed and showed no significant differences between the systems 1 to 2 years after implant loading. Keywords: clinical study, dental implants, EDAX, SEM, surface analysis, titanium

Implant failures often give rise to significant bone resorption, which can jeopardize future implantation and cause esthetic and functional problems. One technique now commonly accepted is guided tissue augmentation (GTA) prior to reimplantation. A resorbable collagen membrane clinically tested for 3 years has provided predictable results both in GTA and in guided tissue regeneration (GTR). This article reports a study at 3 and 6 months after use of this collagen membrane in ridge repair. New bone formation, first woven in texture, then lamellar, was observed. Resorbable collagen membranes can provide for ridge enlargement and bone repair without inflammation during healing. Keywords: bone healing, collagenic membrane, guided tissue augmentation, histologic study, osteoformation

The placement of titanium dental implants in atrophic alveolar ridges often requires bone augmentation because of the lack of sufficient bone volume. In a preliminary study of 36 patients, collected borings from implant cavities were used as autogenous bone grafts. In approximately one-half of the patients, a Gore-Tex membrane was also applied. The success of this method was controlled in a second operation, when the membrane was removed or peri-implant soft tissue surgery was necessary. A bony lamella developed in most of the controlled cases. These preliminary results show a method of ecycling autogenous bone as graft material by using collected implant cavity borings, which normally would be discarded. The simplicity of this procedure and the avoidance of a second wound site, or even major surgery, favor its clinical application. Keywords: atrophic alveolar ridge, bone grafting, endosseous dental implant, ePTFE, implant cavity borings, insufficient bone volume, recycling autogenous bone

This report describes the presence of an unusually wide branch of the posterior superior alveolar artery, which descends from the maxillary sinus through the maxillary alveolar bone to the palatal aspect of the alveolar crest. While this intrabony structure was clearly demonstrated using a reformatting program of computed tomography (CT), it was difficult to definitely identify by panoramic or periapical radiographs. Complications in implant treatment were thus avoided by preoperative analysis of the tomography. Keywords: anatomic variation, computed tomography, dental implants

Sixty-six consecutive patients treated at the Prosthodontic Clinic in Uppsala, Sweden, received implant-supported fixed prostheses of the Brånemark type. The prosthesis frameworks were made of cobalt-chromium alloys. Different techniques for attaching the gold cylinders to the frameworks were used. Mechanical attachment with autopolymerizing polymethyl methacrylate resin (PMMA), partial soldering combined with PMMA attachment, and soldering only were used. No abnormal tissue reactions were seen. Radiographic examination of the implants was performed at the time of prosthesis placement and at the 1- and 3-year follow-up visits. A few cases of minor bone loss were detected but not related to the materials used in the superstructures. Keywords: alloys, Brånemark implants, design, framework, osseointegration, prosthodontics, soldering