Components Of Implant Protective Occlusion – A Review

摘要

The clinical success and longevity of endosteal dental implants are controlled, in a large part, by the mechanical milieu within which they function. The occlusion is a critical component of such a mechanical environment. "Implant-protected occlusion" refers to an occlusal scheme that is often uniquely specific to the restoration of endosteal implant prostheses. This review article focuses on the various aspects of implant protective occlusion. Following these guidelines while developing an occlusal scheme can result in successful and long-term functioning of the implant prosthesis. Introduction The clinical success and longevity of endosteal dental implants as load-bearing abutments are controlled largely by the mechanical setting in which they function. The treatment plan is responsible for the design, number, and position of the implant. After achievement of rigid fixation with proper crestal bone contour and gingival health, the mechanical stress or strain beyond the physical limits of hard tissues has been suggested as the primary cause of initial and long-term bone loss around implants. 1 Occlusal overload and its relationship to implant overload and failure is a well-accepted phenomenon. 12 The issue of occlusal overload and its relationship to crestal bone loss has been well established by Misch and others. Biomechanical overload leads to various sequelae which are detrimental to the successful functioning of the implant supported prosthesis. (Table1). However some authors suggest that little scientific evidence supports a direct cause-effect relationship between occlusal factors and deleterious biological outcomes for osseointegrated implants. 3 Table 1: CONSEQUENCES OF BIOMECHANICAL OVERLOAD: 1 Early implant failure Early crestal bone loss Intermediate to late implant failure Intermediate to late implant bone loss Screw loosening (abutment and prosthesis coping) Uncemented restoration Component fracture Porcelain fracture Prosthesis fracture Peri implant disease (from bone loss) After successful surgical and prosthetic rehabilitation with a passive prosthesis, noxious stress and loads applied to the implant and surrounding tissues result primarily from occlusal contacts. The choice of an occlusal scheme for implant-supported prosthesis is broad and often controversial. The restoring dentist has specific responsibilities to minimize overload to the bone-to-implant interface. These include a proper diagnosis leading to a treatment plan providing adequate support, based on the patient’s individual force factors; a passive prosthesis of adequate retention and form; and progressive loading to improve the amount and density of the adjacent bone and further reduce the risk of stress beyond physiologic limits. The final element is the development of an occlusal scheme that minimizes risk factors and allows the restoration to function in harmony with the rest of the stomatognathic systemImplant Protective Occlusion: A proper occlusal scheme is a primary requisite for long-term survival, especially when para function or a marginal foundation is present. Abnormal occlusal forces, such as those caused by bruxism or clenching, may also contribute to prosthetic complications. 5 These habits are not a contraindication for implant dentistry, but must be diagnosed and compensated for in the final prosthetic design. The use of adjunctive protective guards is mandatory. Implant-protective occlusion (IPO) is an occlusal scheme suggested to decrease overload on the implant supported prosthesis and enable its successful functioning in the oral set-up. The IPO concept addresses several conditions to decrease stress to the implant interface. (Table 2) This occlusal scheme is a combination of various principles which need to be addressed when fabricating implant supported prosthesis. Table 2: IMPLANT-PROTECTIVE OCCLUSION: 1 No premature occlusal contacts or interferences: timing of occlusal contacts Influence of surface area Mutually protect