The International Journal of Oral & Maxillofacial Implants, 02/1992

A simple procedure has allowed consistent visualization of the titanium boundary of the bone-implant interface of osseointegrated titanium implants at the electron microscope level. This was accomplished by embedding the intact bone-implant specimen block with low-viscosity resin prior to removal of the device in preparation for sectioning. The titanium boundary consisted of either a thin, compact amorphous electron dense layer, a broad layer of dense amorphous granules, or both. This material was removed by decalcification in formic acid (prior to embedding) and did not diffract electrons (ie, was noncrystalline). Scanning-transmission electron microscopy-EDX analysis indicated the presence of titanium, calcium, and phosphorus in the electron dense material. Field emission scanning electron microscopy-EDX dot-mapping analysis confirmed the presence of these elements and mapped them to the same locations at the implant-interface boundary. Keywords: healing, implants, interface, osseointegration, titanium

Overdentures were consecutively inserted in 92 severely resorbed maxillae and followed for 1 year. The dentures were supported by a total of 430 implants. Of these, 69 (16%) became loose and were removed during the follow-up period. The mobile implants caused 7 complete failures of the overdenture treatment. Postinsertion maintenance was more extensive for the overdentures than for fixed prostheses supported by implants. Problems arose in relation to the mucosa around the implants, and there were also fatigue fractures of the acrylic resin and the retentive clips. Fewer speech problems were reported in the overdenture group when compared to those with fixed prostheses. Keywords: Brånemark implants, complications, edentulous maxilla failures, overdenture, resorbed maxilla

Selected surface characteristics of screw-type titanium dental implants from four different manufacturers were evaluated. Considerable differences in surface and near-surface contaminants were demonstrated. The fixture treated with radiofrequency glow discharge (plasma) demonstrated the thinnest titanium oxide layer and the cleanest surface. Keywords: contaminants, dental implant, emission spectroscopy, oxide thickness, surface analysis, titanium

Mandibular onlay composite grafts (autogenous iliac bone and titanium cylindrical threaded endosseous dental implants) were placed in seven patients with advanced bone resorption. All seven patients have experienced uncomplicated healing and continuous, uninterrupted prosthesis use without soft tissue or mechanical complications for 1 to 4 years. This preliminary report includes a discussion of the indications for the procedure, potential alternative management of the severely resorbed mandible, and details of the surgical procedure illustrated by two patients who received this treatment modality. Keywords: endosseous dental implants, mandibular bone graft

The purpose of this study was to determine masticatory and functional forces in three axes on mandibular implants supporting overdentures. Five edentulous test subjects were selected, each having two mandibular implants. Three-dimensional piezoelectric force transducers were mounted on the two-part ITI Bonefit implants and rigidly connected to the denture. Forces in vertical, lateromedial, and anteroposterior directions were measured by means of electrostatic plotter records. The test modalities were light tapping, grinding, maximal occlusal force, and chewing test food. Results showed that the five subjects developed similar stress patterns but quantitatively different occlusal and chewing forces. In all but one subject, reduced maximal occlusal force was found compared to dentate subjects and edentulous subjects with fixed partial prostheses supported by implants. The recordings of chewing cycles when eating test food resulted in very regular rhythmic strokes, similar to those of dentate subjects but with slightly reduced speed. All stress patterns showed that occlusal and chewing forces were mainly directed in vertical, medial, and anterior dimensions. The dominating component was vertical. Keywords: chewing force, implants, occlusal force, overdentures, three-dimensional measurement

Partial edentulism in 34 patients was consecutively treated using the Brånemark osseointegration technique. A total of 102 implants was tested for mobility, signs and symptoms of infection, and radiographic bone levels. All patients had at least a 6-month follow-up of prosthesis function (mean 22.5 months). An overall success rate of 88.2% was observed. Twenty-five of 28 maxillary implants and 65 of 74 mandibular implants were successfully placed and restored. Twelve failures; were observed; 7 were not integrated at the time of stage 2 surgery while 5 occurred after prosthetic reconstruction. The results of this study suggest that the Brånemark osseointegration procedure can be used to treat partially edentulous patients with a high degree of success. Keywords: partial edentulism, osseointegration, success/failure

Surgical ablation in the nasofacial area may lead to defects that can be treated with maxillofacial prosthetic restorations retained by osseointegrated implants. When the prosthesis is large or impacted by masticatory or orbicularis muscle forces, the use of implants placed in available facial skeleton bone may be desirable. Available sites for implant placement in the facial skeleton are described, and a craniofacial site classification is suggested. Two examples of patients treated for nasofacial defects are presented. Keywords: craniofacial site classification, episthesis, nasofacial prosthesis, osseous capacity, skeletofacial osteology

The purpose of this experiment was to observe and measure the distribution of heat to bones and the maximum temperature that developed when cutting bone with drills. Generation of heat that spread in the presence or absence of irrigation when drilling with IMZ, Brånemark, and ITI implant (F type) drills was observed in the pig rib via thermography. Without irrigation, the condition of heat spread in each drill and bur differed according to bur shape and drilling site. Maximum heat temperature without irrigation was higher than that with irrigation for any IMZ, ITI, and Brånemark drill. Keywords: bone preparation, cutting instrument, heat generation, irrigation, thermography

This paper reviews investigations concerning the clinical parameters of evaluating dental implants during the maintenance phase of therapy. Clinical parameters that are discussed include mobility, gingival alterations, tissue movement, probing and attachment level measurements, bleeding upon probing, occlusion, and microbial monitoring. The role of implant radiology is discussed and encompasses radiographic interpretation, interval, and technique. Keywords: implants, maintenance, probing, radiographic technique

To investigate public awareness and acceptance of dental implants, 120 adult US citizens were asked to answer a questionnaire. Of the 109 persons who completed the questionnaire, 77% had heard about dental implants, mostly through media and lay persons. Only 17% named a dentist or physician as the source of information. Persons with many missing teeth were not more aware of implants than those with fewer missing teeth. Of 19 removable denture prosthesis wearers, 15 knew about implants but only one third learned of them from their dentist or physician. Of 84 persons with information about implants, 51 would consider implant treatment, 17 would not, and 16 were undecided. Esthetics was the most frequent motivating factor favoring implants, while high cost was the most frequent argument against them. Younger interviewees were significantly more often in favor of implants than older persons. It was concluded that public awareness and acceptance of dental implants are high. Dentists and physicians, however, play only a minor role as sources of information. Keywords: acceptance, dental implants, public awareness, source of information

Insufficient bone volume can be a significant problem when placing dental implants. This clinical study was designed to evaluate bone regeneration potential at dehisced dental implant sites. Nineteen titanium dental implants with exposed threads were studied. To create a secluded space for bone formation, an expanded polytetrafluoroethylene (e-PTFE) membrane was placed over the exposed implant sites secured with an implant cover screw and completely covered with the flap. Three membranes perforated the overlying soft tissue during the healing time and were removed prematurely. The remaining membranes were removed after an uneventful healing period of 4.5 to 6 months. Fourteen of 19 dehisced implant sites were completely covered with newly formed bonelike tissue; 4 implants demonstrated partial bone fill at reentry and 1 implant showed partial fill with soft tissue. In five implant sites a reentry was performed between 6 and 9 weeks; nonmineralized fibrous tissue was found to fill the space under the membrane. At 16 of the 19 implant sites there were similar dehiscence-type defects that were evaluated as a group. These dehiscences varied from 2.0 to 9.0 mm. The percentage of bone fill at reentry ranged from 28.4% to 100% (mean 89.6%; SD 22.51; SE 5.63) and was highly significant (P .0001). Six to 12 months after prosthesis connection, 12 of the 19 implants were available for radiographic interpretation and an average bone loss of 1.73 mm (SD = 0.43) was measured. This surgical application of an e-PTFE membrane suggested a viable clinical method for enhancing bone formation around dental implants. Keywords: bone regeneration, clinical study, dehisced implant site, e-PTFE membrane, osteogenesis, titanium implant

A modified technique for presurgical evaluation of intraosseous implant placement using linear tomography has been developed. The simplified technique is applicable to tomographic systems equipped with a cephalometric head positioner (cephalostat) and a fiberoptic positioning light system. It provides precise cross-sectional images for the assessment of bone morphology and associated anatomic structures. This technique is more comfortable for patients who are unable to tolerate the positioning of submentovertex projections used to estimate horizontal angulation of the head position and to determine the depth of radiographic cut. Instead, the positioning light and casts are used to make these two determinations. Keywords: implant placement, linear tomography, presurgical evaluation

Functional and anatomical considerations led to a new concept of an implant-supported bar prosthesis in the edentulous maxilla. The cantilever situation is avoided by the placement of endosseous cylindrical implants (type IMZ) in the maxillary tuberosities distal to the maxillary sinus. Full arch support is provided by the symmetrical insertion of six IMZ implants in the tuberosity, canine, and incisor regions. After 4 months of healing, a milled precision bar and removable prosthesis are fabricated and supported by the implants. Keywords: bar prosthesis, edentulous maxilla, load distribution, osseointegrated IMZ implants

This article describes postimplant follow-up and retreatment of a 66-year-old patient with an esthetically compromising fixed maxillary tissue-integrated prosthesis and a mobile mandibular overdenture stabilized by precision attachments with a gold clip bar cemented to the transmucosal posts of a bone plate staple implant. Following successful completion of prosthodontic treatment, the patient returned with a fracture of the left transmucosal pip in the mandibular bone plate staple implant that was retreated with Brånemark implants and a fixed prosthesis. Keywords: Brånemark implant, Ceka attachment, complications, neurovascular bundle repositioning, overdenture, severe mandibular resorption, staple implant, transmucosal pin