Determination of vertical dimension of an implant-supported prosthetic rehabilitation with surface electromyography: case report

Determination of vertical dimension of an implant-supported prosthetic rehabilitation with surface electromyography: case report. Abstract The aim of each prosthetic rehabilitation is to achieve a proper occlusion structurally and functionally integrated in the individual neuromuscolar system. This is particularly important in implant-supported prosthetic rehabilitation because the main cause of implant failure is the presence of an abnormal forces distribution(1). The forces acting on a prosthetic rehabilitation are amplified by an incorrect determination of Vertical Dimension(2). The methods proposed in the literature for the determination of occlusion Vertical Dimension are manifold but at present there is no consensus on the methodology to be used for both the variability of results between different methods, both because no author takes into account the effect that the new Vertical Dimension produces on the neuromuscular individual system(3-5). The aim of this study is to evaluate the possibility of determining a "individually correct" Vertical Dimension through the use of the Surface Electromyography (sEMG). For this study was selected one male patient, 55 age old, which needed of an superior overdenture. Were performed three acquisitions throught the use of the electromyograph*: the first at the time of delivery of provisional prothesis, the second after modify of provisional prosthesis and the third at the delivery of final prosthetic. The "individually correct" Vertical Dimension was achieved by the modify of provisional prosthetic, following the stabilization of indices indicated by the software**: Temporal POC, Masseter POC, Activity Coefficient, Asymmetry Index, Torque and, above all, Impact.. At the time of delivery of final prosthesis, all the considered indices showed the values in the biological range. The results obtained show that the use of surface electromyography allows to combine the qualitative information with quantitative measurements, allowing the determination of a individually correct Vertical Dimension. The use of this tool, therefore, can become part of the prosthetic protocol, guiding the operator through the various phases of the prosthetic rehabilitation. This can certainly influence in positive the success rate of implant, since in a system in neuromuscolar equilibrium the overload components of the implant are reduced. A proper distribution of masticatory loads through the prosthetic system, in conjunction with proper hygiene procedures and appropriate strategies for the preservation, is the best guarantee of long-term survival of each implant-supported prosthetic rehabilitation.