BIOMECHANICAL ASPECTS ON OVERDENTURE TREATMENT

Objectives: Implant retained overdentures utilize a wide range of atta chments to provide the retentive forces for implant retained overdentu res. Such attachments attempt to minimize the functional stresses at t he implant-overdenture interfaces. Study selection: Clinical experimen ts with strain gauges can monitor the types and magnitudes of deformat ion that appear in the underlying surfaces. Clinical results have show n that fixed and removable prostheses perform differently in type, mag nitude and direction of the applied load from laboratory tests. There is good correlation between short term clinical experiments and long t erm clinical follow-ups of prosthesis provision. Removable prosthetic superstructures perform at a lower level of overall functional rigidit y with increased risk of deformation. Factors that influence the loadi ng patterns and surface straining are the incorporation of an internal metal frame, the rheological properties of the foodstuff, the occlusa l position of the teeth and the degree of fit of the prosthetic supras tructure and the implants. Conclusions: The prognosis of implant retai ned overdentures is maximized when the number of fixtures used is high , a rigid bar design is used and functional flexibility is incorporate d in the prosthesis design. (C) 1997 Elsevier Science Ltd.