Pages 175-176, Language: English
Pages 183-190, Language: English
The bone biopsy chamber (BBC) has been developed for implantation in bone to permit the serial biopsy of osseous tissues to study osseointegration. This device improves the currently available methodology for studying the implant/osseous interfacial zone by providing a means of collecting osseous samples for microscopic evaluation in the least invasive manner, and without euthanization or en bloc resection. The advantages of the BBC were verified through its implantation in the tibia of five young adult Flemish Giant rabbits and the serial collection of osseous samples. Following the recommended surgical procedures to implant the BBC and obtain osseointegration, osseous samples were collected from the five rabbits at 30-, 60-, and 90-day test periods for histologic evaluations. Bone specimens were embedded in preparation for staining using modified goldner trichrome, toluidine blue, and gallocyanin. Each of the sections demonstrated clear evidence of biocompatibility, the different cellular components and stages of osteogenesis, and that osseous tissue biopsies were possible using this device.
Keywords: bone biopsy, bone regeneration, titanium implants
Pages 191-198, Language: English
A panel of monoclonal antibodies was used in an avidinbiotin immunoperoxidase technique to provide an immunohistologic analysis of the inflammatory infiltrates in the gingiva of osseointegrated implants. A total of 27 gingival and 13 interimplant specimens was obtained from 13 patients. Eighteen of the gingival specimens were clinically healthy, while nine showed overt signs of clinical inflammation (GI = 2 or 3). All specimens showed some degree of inflammation histologically, although the size of the inflammatory infiltrate was much greater in the clinically inflamed specimens. There was no significant difference in the proportion of T (50% to 60%) or B (40% to 50%) lymphocytes in either group. The CD4:CD8 ratio also showed no significant difference: 1.6:1 in the healthy group and 2.0 in the inflamed group. Similar ratios were also found in the infiltrates of the interimplant tissue. The immunohistologic analysis suggests that the gingival lesion associated with these implants is a stable, well-controlled response.
Keywords: immunohistology, osseointegrated implants
Pages 199-204, Language: English
Glow-discharged titanium implants, with a presumed high surface energy, and conventionally prepared and sterilized titanium implants were inserted in the rabbit tibia and femur. The removal torque and histology were compared after 6 weeks in situ. No qualitative or quantitative differences were detected for implants with different preoperative preparation. The results indicate that the conventional implant treatment described is sufficient to give a surface condition with similar early healing responses as those observed with glow-discharge-treated implants.
Keywords: bone apposition, glow discharge, plasma cleaning, surface energy, titanium implants
Pages 205-210, Language: English
Differential chewing function with removable partial dentures (RPDs) and fixed prostheses supported by the single-crystal sapphire implant was evaluated in five subjects with Kennedy Class II partially edentulous mandibles by means of electromyography. Rehabilitation with the single crystal sapphire implant resulted in regular chewing patterns with a low variation coefficient and higher activity of chewing-side masticatory muscles compared to RPD rehabilitation. This difference in chewing function between the two rehabilitation modalities could be the result of differences in stability of occlusion and neurophysiologic feedback systems.
Keywords: chewing function, electromyography, Kennedy Class II mandible, single-crystal sapphire
Pages 211-217, Language: English
A total of 876 consecutively placed fixtures ad modum Brånemark was followed in 268 partially edentulous jaws of 244 patients treated between April 1968 and the end of December 1988. A total of 24 of 712 fixtures exposed at the abutment connection was lost (3%); the continuous prosthesis stability rate was 98.7%, as only four of 293 prostheses were removed. The results of the study indicate the possibility for the Brånemark osseointegration technique also to be used in the treatment of partial edentulism.
Keywords: dental implants, partial edentulism, titanium
Pages 219-225, Language: English
This study evaluated the response of canine mandibular bone to loaded hydroxylapatite-coated (HAC) and grit-blasted titanium (GT) endosseous dental implants. Four dogs were partially edentulated in the maxilla and mandible. Two implants supporting freestanding prostheses were placed in each quadrant. Following 1 and 10 months of loading, the implants were evaluated. Soft-tissue pocket depths were not statistically different between the HAC and GT implants. Crestal bone loss was not significantly different between the two implants. However, the HAC implants had a statistically significant greater amount of bone apposed to their axial and apical surfaces compared to the GT implants.
Keywords: bone remodeling, dental implants, hydroxylapatite
Pages 227-231, Language: English
A patient report is presented illustrating bone growth of the posterior mandible associated with a fixed implant reconstruction of the Brånemark type. In this instance, the mandible had grown vertically approximately 3 mm and was causing discomfort beneath the cantilever sections of the prosthesis because of gingival impingement between the restoration and the bony mandible. The literature relative to osteogenesis associated with osseointegrated implants is reviewed.
Keywords: hyperostosis, implants, osseointegration, osteogenesis
Pages 233-239, Language: English
Clinically retrieved titanium implant cover screws (Brånemark implant system), rinsed in saline or subjected to ultrasonic cleaning and sterilization, as well as unused sterile screws were studied by scanning electron microscopy and implanted in the rat abdominal wall for 6 weeks. Irrespective of cleaning procedure, the heads of the clinically retrieved screws were covered by numerous contaminants not present on the unused screws. The reimplanted screws elicited a different tissue response than the unused screws. The tissue response to the contaminated screws was characterized by a significantly thicker fibrous capsule and by a significantly larger number of macrophages located close to the implant. Moreover, judging from their ultrastructure, studied with transmission electron microscopy, the macrophages appeared to be in a more active state when compared to those located adjacent to unused screws.
Keywords: contamination, macrophages, soft-tissue response, titanium implants
Pages 241-247, Language: English
The placement of fixtures (implants) in relation to the geometry of a prosthetic restoration has a great influence on the mechanical loading of the implant. Based on theoretic consideration and clinical experiences with the Brånemark System, this article gives simple guidelines for controlling these loads. The emphasis is on design rules that can be used in clinical practice. With the Class I lever as a reference, various clinical implant prosthesis situations are discussed and evaluated.
Keywords: Brånemark implant, cantilever, fixture position, force, load, moment
Pages 249-253, Language: English
Panoramic radiography was compared with conventional tomography as techniques for visualizing the mandibular canal. Tomography gave a significantly clearer image of the canal at and 1 cm posterior to the mental foramen. While no differences were found between the methods 2 cm posterior to the mental foramen. Thus, tomograpny could be of great value in locating the mandibular canal before implant surgery in edentulous mandibular posterior segments.
Keywords: mandible, radiography, panoramic radiography, tomography
Pages 255-256, Language: English
Complete circumferential fracture of a basket-type implant 12 months postrestoration is described.
Keywords: basket-type implant, fracture, maintenance, osseointegration