Strain characteristics of Marburg double crown-retained implant overdentures compared with bar and ball-retained implant overdentures, with and without a rigid major connector

Effect of different framework materials on stresses induced in distal extension removable partial dentures: A strain gauge analysis

PURPOSE

Evaluation of the strain transmitted to the abutments and residual ridge by polyetherketoneketone material compared to the cobalt-chromium one in distal extension removable partial dentures (RPDs) to fulfill the objective of preservation of the supporting structures.

MATERIALS AND METHODS

A virtual model simulating a Kennedy class I partially edentulous mandibular arch was designed. Two models, one for each group, were printed. Five RPDs were made in each group. In group CR, the framework was milled from a cobalt-chromium alloy. While in group PK, it was milled from a polyetherketoneketone blank. Strain gauge rosettes were bonded distal to the last abutment and posteriorly in the distal end of the residual ridge. Unilateral vertical and oblique loadings were applied. Mann-Whitney U test was used for inter-group comparisons while the Friedman test was used for intra-group comparisons and corrected by Wilcoxon Signed-Rank Sum. The significance level was set at p ≤ 0.05.

RESULTS

During unilateral vertical load application, a statistically significant difference was found between both groups distal to the abutment in the loaded and unloaded sides as well as the residual ridge on the unloaded side. During oblique load application, a statistically significant difference was found between both groups in all slots.

CONCLUSION

Polyetherketoneketone material induces less stress on the abutments and more stress on the residual ridges compared to the cobalt-chromium ones. Therefore, it may be recommended for weak abutments supporting RPDs.

Biomechanical aspects of reinforced implant overdentures: A systematic review

PURPOSE

The purpose of this systematic review was to investigate the effect of reinforcement on the mechanical behaviour of implant overdenture (IOD) bases and its cumulative biological effect on the underlying supporting structures (implants and the residual ridge).

MATERIAL AND METHODS

The required documents were collected electronically from PubMed and Web of Science databases targeting papers published in English that focused on denture base reinforcement for IOD prostheses in order to recognize the principal outcomes of reinforcement on the mechanical and biological properties of overdentures. Such biological outcomes as: strains on implants, peri-implant bone loss, residual ridge resorption, and strain on the residual alveolar ridge.

RESULTS

A total of 269 citations were identified. After excluding any repeated articles between databases and the application of exclusion and inclusion criteria, only 13 publications fulfilled the inclusion criteria. Three publications investigated the mechanical properties of fibre and/or metal-reinforced implant overdentures while another 3 articles investigated the effect of metal reinforcement on stress distribution and strains transmitted to the underlying implants. In addition, 3 in vitro studies investigated the effect of metal reinforcement on overdenture base strain and stresses. Stress distribution to the residual ridge and strain characteristics of the underlying tissues were investigated by 2 in vitro studies. Five clinical studies performed to assist the clinical and prosthetic maintenance of metal-reinforced IOD were included. Data concerning denture base fracture, relining, peri-implant bone loss, probing depth, and implant survival rates during the functional period were extracted and considered in order to evaluate the mechanical properties of the denture base, residual ridge resorption and implant preservation rates, respectively.

CONCLUSION

The use of a denture base reinforcement can reduce the fracture incidence in IOD bases by enhancing their flexural properties and reducing the overdenture base deformation. Strains on the underlying supporting structures of overdenture prostheses including dental implants and the residual ridge can be decreased and evenly distributed using a metal reinforcement.

Telescopic Denture

Aim:

This article explains the concept of telescopic denture.

Procedure:

It describes the different types of telescopic attachment (or double crown), and provides an overview of the advantages and the disadvantages of this type of prosthodontic treatment.

Conclusion:

The indications and the clinical applications of telescopic denture are discussed.