Effect of preloading on lower jaw implant

The procedure of mandible resection is basically unavoidable in case of cancer in the field of oral surgery. The reinforcement and the reconstruction of the jaw closest to its original condition is very challenging. Considering the load properties the examination of the plates used in the reconstruction is highly important. The cadaver examination procedure however is very difficult to execute, therefore the use of the Finite Element Analysis proves rather supportive. Fast recovery can be achieved by applying the implants correctly. Furthermore brakeage resulting from high loads in the plates can be avoided. The goal is to examine and understand the Non-locking screwing technique used with plate implants in different mandible resections and reconstructions, focusing on the preloaded force. Furthermore the study and comparison of different stress that arise in different cases. A toothless mandible was used for the creation of the Finite Element Analysis model. The data was provided for the model by CBCT. During the creation of the model we separated four different resection areas to which we used the plates with the Non-Locking screwing technique, also used in clinical reconstructions. For the preload of the plates we used different preloaded forces on the screws. We considered and used boundary conditions complying with the anatomical structure. The muscles required for chewing were transferred to the model and used as main loads. The bone structure is heterogenic and the bone density is based on CBCT. The preloaded forces have a major role in the stresses arising in the bone during the use of Non-locking technique. The comparison of the resection techniques can provide valuable information regarding the preloaded condition and the following chewing load condition connected to the main loads in the bone. Those measurements that are important from biomechanical point of view and would prove difficult or impossible with in vivo or in vitro load measurements to be examined can be compared with the Finite Element Analysis method. DOI:  10.17489/biohun/2013/1/03