A meta-analysis of implants in partial edentulism

Clinical Experiences of Implant-Supported Prostheses with Laser-Welded Titanium Frameworks in the Partially Edentulous Jaw: A 5-Year Follow-up Study

BACKGROUND

Titanium frameworks have been used in the endentulous implant patient for the last 10 years. However, knowledge of titanium frameworks for the partially dentate patient is limited.

PURPOSE

To report the 5-year clinical performance of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw.

MATERIALS AND METHODS

A consecutive group of 383 partially edentulous patients were, on a routine basis, provided with fixed partial prostheses supported by Brånemark implants in the mandible or maxilla. Besides conventional frameworks in cast gold alloy, 58 patients were provided with titanium frameworks with three different veneering techniques, and clinical and radiographic 5-year data were collected for this group.

RESULTS

The overall cumulative survival rate was 95.6% for titanium-framework prostheses and 93.6% for implants. Average bone loss during the follow-up period was 0.4 mm. The most common complications were minor veneering fractures. Loose and fractured implant screw components were fewer than 2%. An observation was that patients on medications for cardiovascular problems may lose more implants than others (p < .05).

CONCLUSIONS

The clinical performance of prostheses with implant-supported laser-welded titanium frameworks was similar to that reported for conventional cast frames in partially edentulous jaws. Low-fusing porcelain veneers also showed clinical performance comparable to that reported for conventional porcelain-fused-to-metal techniques.

Complications in Partially Edentulous Implant Patients: A 5-Year Retrospective Follow-up Study of 133 Patients Supplied with Unilateral Maxillary Prostheses

BACKGROUND

Numerous studies have reported successful outcomes for restoration of fully edentulous patients with Brånemark implants. However, some studies indicate more mechanical problems in restored partially edentulous situations.

PURPOSE

The objective was to study patients with potential risk for mechanical complications after implant treatment.

MATERIALS AND METHODS

Patients were retrospectively evaluated 5 years after implant treatment in upper jaw Appelgate-Kennedy Class II situations. Altogether 422 implants ad modum Brånemark were installed in 137 consecutively treated patients. One hundred thirty-three prostheses were placed and followed-up for 5 years, according to routine clinical protocols.

RESULTS

The overall 5-year implant cumulative survival rate (CSR) was 94.0%. The corresponding CSR for loaded implants and prostheses was 97.7% and 98.4%, respectively, and the overall marginal bone loss was 0.8 mm (+/- 0.6 mm) after 5 years. Sixteen abutment screws fractured in seven patients (5%) and 17 prostheses (13%) presented loose abutment or gold screws during the follow-up period. Significantly more problems were reported in association with prostheses that included the canine (p < .05), and significantly more gold screws were working loose when only two implants were supporting the frameworks (p < .01).

CONCLUSIONS

Upper jaw implant treatment in unilateral free-end situations seems to involve more mechanical problems than other implant treatment groups when only two implants can be installed and when the canine tooth is missing. However, most of these complications are easily adjusted, and the clinical survival of implants and prostheses is the same for these groups compared to other groups of partially edentulous implant patients.

Biomechanical and functional behavior of implants

The ability to achieve a long-term stable implant interface is not a significant clinical issue when sufficient uni- or bi-cortical stabilization is available. Clinical outcomes studies suggest that the higher-risk implants are those placed in compromised cortical bone (thin, porous, etc.) in anatomic sites with minimal existing trabecular bone (characterized as type IV bone). In establishing and maintaining an implant interface in such an environment, one needs to consider the impact of masticatory forces. These forces, in turn, have the potential to create localized changes in interfacial stiffness through the viscoelastic properties of bone. Changes in these properties will alter the communication between osteocytes and osteoblasts, leading to an increase in new bone growth, a maintenance of established bone, or a loss (potentially catastrophic) of either cortical or trabecular bone. Therefore, a key to understanding the biomechanical and functional behavior at an implant interface is to control the extent of anticipated modeling and remodeling behavior through an optimal implant design combined with a thorough understanding of how tissues respond to the mechanically active environment.

Toward an understanding of implant occlusion and strain adaptive bone modeling and remodeling

STATEMENT OF PROBLEM

Dental implant failure rates for osseointegration are greater in the highly atro-phic maxilla. Presuming higher failure rates relate to strain-driven adaptation, an enhanced understanding of formative bone response to loading (modeling) and maintenance of an integrated state (remodeling) should improve treatment.

PURPOSE

To understand the role of occlusal loading on long-term osseointegration in areas of compromised cancellous bone, a review of the salient features of adaptive bone modeling and remodeling is presented with an emphasis on cancellous bone responses.

CONCLUSIONS

The ability for dental implants to maintain a long-term stable interface in the maxilla lies in the ability of trabecular bone to maintain adequate local material (strength) and architectural (connectivity) properties. In this discussion, an emphasis has been placed on understanding how trabecular bone can respond to the mastication-induced loading environment on an implant.