Prosthetic Phase Research Articles

Tissue volume considerations in implant prosthodontics

Statement of problem. The replacement of intraoral hard and soft tissue is dependent on careful dimensional consideration. The prosthetic phase of implant treatment frequently involves the restoration of significant amounts of hard and soft tissue in addition to teeth. Although similarities to both tooth supported fixed prostheses and removable prostheses exist, implant-supported fixed prostheses engender unique problems with respect to prosthetic contours. Purpose. This article depicts diagnostic methods used to compare anticipated prosthesis volume with existing clinical conditions. The proper functional, esthetic, and biomechanical design of the definitive prosthesis will be shown to relate directly to understanding these dimensional requirements. (J Prosthet Dent 1997;77:492-6.)

An accurate impression method for implant prosthesis fabrication

The long-term success of an implant prosthesis depends not only on the development of osseointegration, but also on the maintenance of osseointegration after the prosthetic phase. To achieve this, a passive superstructure must be fabricated. Errors that result from the impression transfer method of implant position during the impression procedures often made it necessary to section and solder metal frameworks repeatedly. This article presents a modified impression technique intended to deal with the problems of more traditional impressions with the aim of achieving a more accurate master cast.

Esthetic and functional considerations for implant restoration of the partially edentulous patient

Suggestions for esthetic enhancement are provided and functional and occlusal considerations discussed for the partially edentulous implant candidate. Among the techniques the surgical/restorative team might consider are sinus lifts, bone contour augmentation for enlarging alveolar width, nerve repositioning, guided tissue regeneration, and soft tissue augmentation with split-thickness palatal grafts for gingival harmony. Mounted diagnostic casts and wax-ups should be prepared. Specific suggestions for esthetic enhancement include orthodontic correction of drifted or hypererupted teeth, possible segmental or full arch orthognathic surgery, soft tissue augmentation, and the assessment of gingival consistency and thickness around the adjacent teeth. Suggestions to address the functional demands of fixed restorations include presurgical procedures to permit maximum implant lengths and optimal angulation, the use of a nonlinear tooth arrangement, long-term maintenance of the occlusion, and positioning implants in the original tooth positions to create natural cervical emergence profiles. For single-tooth restorations, implants should be placed at least 3 mm apical to the cementoenamel junctions of the adjacent teeth. Satisfactory surgical handling of the interproximal papillae is necessary to maintain appropriate contours. Modifications of gingival architecture should be made during the prosthetic phase of treatment.

A survey of dentists practicing implant dentistry in Israel

Due to the increasing interest in the field of implant dentistry, a first survey of dentists in Israel who used implants was conducted. Out of a total of 312 dentists questioned, 97 reported using dental implants in their practice. In spite of the team approach advocated in the literature, 40% of the dentists in the survey conducted both the surgical and the prosthetic phases of treatment. Over 60% of the respondents had less than 3 years' experience in the field, which is in keeping with the worldwide trend. A smaller number than expected regarded red gingival color and bone resorption based on radiographic findings as grounds for implant failure. In the view of at least 10 respondents, pain, discomfort, exudate, and fistulization did not indicate unsuccessful implants. A disparity was revealed between the dentists' practice methods and their hypothetical choice of self-treatment. Although the Core-Vent method was the most widely employed, only 50% of those using this system preferred it for themselves. Even fewer (25%) of those using blade implants considered it their self-treatment of choice. In contrast, although only 10% of the dentists had used the Branemark method, 30% preferred it for their own treatment.

A retrospective multicenter evaluation of the survival rate of osseointegrated fixtures supporting fixed partial prostheses in the treatment of partial edentulism

Whether the excellent prognosis of the osseointegration technique also applies for the rehabilitation of partially edentulous jaws was investigated through a multicenter retrospective study. Six centers from three continents participated in the study, which included 133 fixtures in 38 patients. Forty fixtures were installed in the upper jaw and 93 in the lower jaw. The observation time varied between 6 and 36 months after prosthetic reconstruction. Clinical evaluation included mobility measurement of the restorations and control of infectious or neurologic complication. Radiologically the absence of radiolucency around the fixtures was checked by a single observer who also calculated the distance between the marginal bone and the top of the fixture. Fifty-eight percent of the prostheses were connected to natural teeth. The success rate for the individual fixtures in the upper and lower jaws was 87% and 92%, respectively. The most failures occurred before the prosthetic rehabilitation. The mean maximum distance between the margin of the bone and the fixture-abutment junction was 2.5 mm. Since only two of the 53 fixed prostheses were lost during the observation period, and since most fixture losses occurred before the prosthetic phase of the treatment, this study supports the concept that osseointegrated prostheses can also be applied to the rehabilitation of partial edentulism.

Energy cost of loads carried on the head, hands, or feet.

Energy cost of loads carried on the head, hands, or feet.

Gingivectomy and crown preparation in occluso-rehabilitation

M OST PATIENTS REQUIRING complete or partial rehabilitation of the mouth present themselves with disturbed and, in many instances, badly broken down periodontal structures. These patients have gone through stages of missing and drifting teeth which have changed the occlusion drastically. The centric, protrusive, and lateral occlusal positions have become accommodated to a malfunctioning set of teeth, and their replacements, both fixed and removable, are constructed to these incorrect positions. In many of these patients, the breakdown of the periodontium proceeds until the end result is an edentulous mouth. In rehabilitating these badly broken down mouths, it is very effective to make preliminary preparations of the teeth for veneers for a quadrant or a half of the mouth during each visit. After the bulk of the crown is prepared, and during the same visit, gingivectomy is performed where it is indicated. It is possible to obtain a simple approach to the proximal pockets after the preparations are started. If there should be an infrabony pocket on the proximal surface and an indication for the surgery of this area, the opportunity for completely cleaning out the area is vastly improv.ed and, in many instances, there may be a visible approach to the pocket. Even if there are narrow tortuous pockets, the technical problem of instrumentation is simplified. From the patient’s point of view, a gingivectomy done during the prosthetic phase is also an improvement. There is excellent local anesthesia. The patient does not require more office visits than the time necessary to complete his prosthesis, and there is no duplication of effort. From the dentist’s point of view, after the gingivectomy is completed, temporary splints can be constructed so that centric occlusion is obtained, and the proper protrusive and lateral components of occlusion are developed. This begins the treatment phase for the periodontium immediately, and it is an excellent test to determine the future maintenance of any questionable teeth. If the periodontium responds within a reasonable time (one to three months), then questionable tooth or teeth may be utilized as abutments if they have been so indicated in the treatment plan. If, after a fair test, there is a negative response, the best approach is extraction of the questionable teeth, and an alternate plan must be accepted. The time of healing with the above procedure is at least equal to that of a gingivectomy performed prior to the crown preparation. The clinical result is also equally favorable, and patients have not shown any unusual discomfort during or after the combined operations. A rehabilitation can be completed with a similar end result in a much shorter time in this way than by doing it separately.