The objective of the present investigation was to evaluate how dental implant positioning can influence the masticatory stress distribution over screwed mandibular prosthodontics restoration and over the surrounding bone tissue. Moreover, the dental implant components and overdenture bar strengths under masticatory cycles have been investigated in order to evaluate possible screw and prosthesis breakage. A “virtual jaw” model and 3D dental implant were reproduced to realise finite element analysis in order to underline the parameters and the mechanical characteristics of the bone and of the dental implants connected to the overdenture bar. The distribution of a nonspecific chewing phase, analysing the overall load on the fixtures of the lower jaw, was performed. The study investigating frontal and horizontal planes and vertical directions of occlusal forces showed how position and perspective of fixtures strongly influenced the stress distribution and the consequent jawbone tissue remodelling. Prostheses elements such as cantilever, passing screws, and dental implants are strictly related to the correct selection of dental implant position. This study suggested a virtual method to guide the surgeon in the choice of implant number, position, diameter, and length, and cantilever length and shape, and to evaluate the prospective stress distribution of chewing strengths for a correct prosthesis rehabilitation.

Prosthetic rehabilitation of total edentulous jaws patients is today a common technique that clinicians approach in their daily practice. The use of dental implants for replacing missing teeth is going to be a safe technique and the implant-prosthetic materials give the possibility of having long-term clinical success. Aim of this work is to evaluate the mechanical features of three different prosthetic retention systems. By applying engineering systems of investigations like FEM and von Mises analyses, how the dental implant material holds out against the masticatory strength during the chewing cycles has been investigated. Three common dental implant overdenture retention systems have been investigated. The ball attachment system, the locator system, and the common dental abutment have been processed by Ansys Workbench 15.0 and underwent FEM and von Mises investigations. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed different response for both types of device, although locator system showed better results for all conditions of loading. The data of this virtual model show all the features of different prosthetic retention systems under the masticatory load. Clinicians should find the better prosthetic solution related to the patients clinical condition in order to obtain long-term results.

The field of dental implantology has made progress in recent years, allowing safer and predictable oral rehabilitations. Surely the rehabilitation times have also been reduced, thanks to the advent of the new implant surfaces, which favour the osseointegration phases and allow the clinician to rehabilitate their patients earlier. To carry out this study, a search was conducted in the Pubmed, Embase and Elsevier databases; the articles initially obtained according to the keywords used numbered 283, and then subsequently reduced to 10 once the inclusion and exclusion criteria were applied. The review that has been carried out on this type of surface allows us to fully understand the features and above all to evaluate all the advantages or not related. The study materials also are supported by a manufacturing company, which provided all the indications regarding surface treatment and confocal microscopy scans. In conclusion, we can say that, thanks to these new surfaces, it has been possible to shorten the time necessary to obtain osseointegration and, therefore, secondary stability on the part of implants. The surfaces, therefore, guarantee an improved cellular adhesion and thanks to the excellent wettability all the biological processes that derive from it, such as increases in the exposed implant surface, resulting in an increase in bone-implant contact (BIC).