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Peri-implant bone resorption has been reported around some implants after loading, which could create problems for the peri-implant soft and hard tissues’ long-term stability. The reasons for this are still not known. However, relevant importance could be given to this due to the presence of a bacterial contamination at the micro-gap level between implant and abutment. In this regard, external and internal implant–abutment assemblies have been shown to be much more permeable to bacterial colonization than Cone-Morse or conical connections. The placement of a subcrestal implant could have aesthetic advantages, therefore allowing a better prosthetic emergence profile. In literature, controversial experimental and clinical results have been reported on bone resorption around implants placed equicrestally and subcrestally. Interestingly, Finite Element Analysis (FEA) studies revealed to be extremely useful for assessing the peri-implant bone strain and stress. Thus, this study conducted a FEA evaluation of implants with a Cone-Morse implant–abutment assembly inserted into a bone block model mimicking equicrestal (0 mm) and subcrestal placements (−1 and −2 mm). Results demonstrated that maximum stresses were observed in the cortical bone around equicrestally placed implants, with the lowest in the 2 mm subcrestally placed implant and intermediate stresses within the 1 mm subcrestally placed implant. The cortical bone resulted more stressed under lateral loads than axial loads. In conclusion, this FEA study suggested a subcrestal implant placement ranging between −1 and −2 mm to obtain an adequate peri-implant stress pattern.

The aim of biomechanics applied to implantology is to determine the deformative and tensional states by solving the equilibrium equations within the mandibular bone and the osseointegrated implant to ensure its stability and improve the success rate. The finite element method is a powerful numerical technique that uses computing power to derive approximate solutions for the analysis of components with very complex geometry, loads, materials, and especially the biomechanical problems analysis, which is challenging to find in vivo or in vitro. This study performs a complete FEA survey on 3 implants Cono-in with 3 different diameters 3.4 mm, 4.5 mm, and 5.2 mm with abutments inclined to 15° and evaluates the tensions that are generated in the system as a result of the application of chewing loads. In this study, the extent of the stresses developed in the peri-crestal zone of the implants with the variation of the occlusal overstress acting on them was also evaluated. Autodesk Inventor Nastran Software was used to perform this type of localized finite element analysis; With this type of analysis, it was possible to analyze the peri-crestal area of the implant more precisely through a more accurate reconstruction of the mesh element, which allowed us to solve the FEA solution mathematically. The results showed how the application of the inclined load with respect to the vertical load on a larger diameter system leads to an increase in stress.