Stress on root and crown surfaces of inlay-supported and conventional bridges: Finite element analysis

Inlay-supported bridges can be a good alternative to conventional bridges because they are minimally invasive and aesthetically pleasing. However, inlay-supported bridges do not surround the tooth as in conventional bridges, which may cause different stress distributions. The high stresses that may occur can cause devastating damage to the teeth and surrounding tissues. The aim of our study is to evaluate the stresses that inlay supported bridges can create compared to conventional bridges, on the connector region, preparation surfaces, tooth neck region and cortical bone surfaces. In our study, which is planned in the absence of left mandibular first molar, there are four different groups consisting of inlay supported and conventional bridges designed from gold alloy supported porcelain and monolithic zirconia material. Von Misses stress values and minimum principal stress values formed by applying 600 N oblique and vertical loads to the groups were discussed. The research was carried out by performing static linear analysis with three-dimensional finite element stress analysis method. When the connector region was evaluated under the applied axial and oblique forces, gold alloy supported models showed lower stress accumulation than monolithic zirconium models. Under axial force, inlay supported bridge models showed lower stress accumulation than conventional bridge models. When the preparation surfaces were evaluated, monolithic zirconia groups showed higher stress accumulation than gold alloy groups. Monolithic zirconia showed higher stress accumulation than gold alloy at apical stresses in both conventional bridge and inlay supported bridge groups. When the stresses occurring in the neck region are evaluated, compared to monolithic zirconia gold alloy groups, conventional bridges showed lower stress accumulation compared to inlay supported bridges. The stresses occurring in the cortical bone were found to be under the destructive effect for all groups. In addition, within the limits of this study, it is observed that oblique forces have a more destructive effect against vertical forces. However, long-term clinical follow-up studies are needed, as well as in vitro studies in which the oral environment is imitated. Keywords: Inlay supported bridge, Monolithic zirconia, Finite element analysis This study was approved by Baskent University Institutional Review Board (Project no: D-DA 20/02) and supported by Baskent University Research Fund.