In Search of An Improved Methodology for Measuring Dental Implant Stability: Combining Experimental Model Analysis (EMA) and Finite Element Analysis (FEA) to Achieve Maximum Reliability

Abstract

Despite the importance of the need for measuring dental implant stability, an effective, reliable methodology has eluded researchers, with current methods used to detect implant stability either in the early stages or incapable of providing a complete picture. This study sought to identify a parameter capable of measuring dental implant stability, to allow for the successful detection of failing implants. Through the combined use of experimental modal analysis (EMA) and finite element analysis (FEA), we examined the accuracy and reliability of three implant stability devices—the Osstell ISQ®, the Periotest®, and the Periometer—by calibrating them via both EMA and FEA, using models of dental implants of various lengths in Sawbones® of different densities. The theoretical mechanics used to operate the three devices were analyzed to understand their assumptions and limitations. To estimate angular stiffness, we employed implant models of various lengths and widths in Sawbones® of different densities. To gauge how effectively Sawbones® and porcine bones could represent human bones, different types of bone models (i.e., porcine bone, human mandibular bone, and Sawbones®) were compared using the Osstell ISQ® and the Periotest® devices, and EMA, in addition to measuring apparent bone density. Micro-computed tomography (micro-CT) was used to estimate bone mineral density (BMD) and morphometric parameters of both porcine and human bone samples. After demonstrating that the three above-mentioned devices were deficient both theoretically and experimentally, we developed an optimal model for implant stability testing through the combined use of EMA and FEA. Natural frequency, although a robust and consistent measurement, does not equate with dental implant stability. Porcine bone may overestimate implant stability measurements when applied to human bones. Sawbones® may provide reasonably good models but should be used with caution. Boundary conditions and experimental setup play an important role in the outcome of research and should be taken into consideration. The angular stiffness coefficient—which is independent of the type of abutment used—was found to represent a superior index for quantification of dental implant stability, successfully differentiating stability of implants of both varying lengths and diameters, while the other methods tested did not.