Dental Implant Prosthetics: Achieving Retrievability and Reducing Treatment Complications by using a Modified Installation Technique Dr. Emil Svoboda
Citation: Dental Implant Prosthetics: Achieving Retrievability and Reducing Treatment Complications By Using a Modified Installation Technique. Emil L.A. Svoboda, OralHealth Oct 2016; 1-8
Abstract: Many clinicians prefer to install the implant prosthetics by the screw-in method, because they believe that this method of installation allows for prosthesis retrievability. However, retrievability does not result from the prosthesis installation method, but relates to “Retrievability Features” created by the implant surgeon and enhanced by the implant manufactures. These features include placing implants in a position that allows for a working path of insertion and a desirable abutment-screw access-hole location. Implant manufacturers have created aids, such as multi-unit abutments and special abutment screws that build some tolerance into the abutment-prosthesis system, for restoring implants in non-optimal positions. Unfortunately, these features do not mitigate the major cause of complications inherent to the screw-in prosthesis installation technique, the implant-abutment misfit. A review of the current literature indicates that complications arising from implant treatment involving fixed prosthetics are 30% for mucositis and 15% for peri-implantitis. This results in an implant failure rate of 4% over 5 years and 8% over 10 years. These complications require treatment and can be expensive for both the patient and dentist. The reviews were unable to discern differences in complications related to the method of prosthesis installation. However, it appears that prosthesis installation methods may be stressing the biological and mechanical systems in different ways. The screw-in installation method includes the extra-oral cementation of the abutment-prosthesis complex, on a model of the mouth. The inaccuracy of this model contributes to the inaccuracy of the abutment-prosthesis assembly. This causes stress and misfits at the implant-abutment connection when it is installed onto implants inside the mouth. Such misfits can lead to mechanical instability of the implant-abutment connection and also renders adjacent tissues susceptible to trauma from joint movement and assault by oral pathogens. The implant-abutment connection can be optimized when the abutments are individually installed into the oral environment and then attached to the prosthesis by means of intra-oral cementation. However, that process in turn, appears to cause another biological problem, due to the advent of residual subgingival cement. Dr. Svoboda has discovered new information about the process of intra-oral cementation that can help prevent this problem. His cement control system includes specific design elements for abutments and their complimentary prosthetics, and involves the use of super low installation pressures during the process of intra-oral cementation. Once the above mentioned retrievability features are in place, the author proposes the “Svoboda Modification” or its “Simplified” version, to both control excess cement and optimize the implant-abutment connection. These proposed modifications are relevant to implant prosthetics that are to be installed by the screw-in method. They have the potential to reduce implant complications by 60%. This estimate has been extrapolated from the study of TG Wilson (J Periodontol 2009;80:1388).