The doctoral thesis deals with issues from the field of dental biomechanics, specifically the mechanical interaction of the dental implant with the bone tissue of the mandible. This is one of the key factors for the success of implant treatment. One method of evaluating this interaction is stress-strain analysis using Frost's mechanostat hypothesis and assessment of the implant to the limit state of elasticity. Since measuring stress and strain in the bone-implant system is very difficult, computational modelling using the finite element method is used in practice. Its accuracy depends on the input data and the quality of the geometry model. The aim of this study was to analyse the influence of various parameters of the computational model and clinical factors on the stress-strain states of bone tissue and the implant itself. In clinical practice, data from CT devices are most commonly used, but these provide only basic information and do not include the detailed trabecular structure of bone tissue. This can be obtained using a high-resolution micro-CT device.
For the purposes of this work, geometry models were created respecting the trabecular structure of bone tissue based on micro-CT data with different resolutions. At the same time, the effect of the used threshold value on the geometry model was assessed. The results showed that both factors have a significant impact on the resulting stress-strain states. The analyses performed show that the influence of the threshold value is more significant when using images with lower resolution. They also show that models created from low-resolution data (150 µm) exhibited higher strains in the bone tissue and coronoapical displacements than models created from high-resolution data (30 and 60 µm). This confirmed that the quality of the input data is crucial for the reliability of the analyses.
The accuracy of implant placement also plays an important role, whereby the implant can be placed using the freehand method or using guided placement. The difference between the angular deviation of the dental implant and the planned position can be significant between these two methods. Based on the analyses, it can be concluded that, in terms of bone tissue evaluation, the position of the implant has a more significant impact than the angular deviation. However, angular deviation appears to be a significant factor in terms of stress on the implant.
The impact of depth of dental implant placement and partial reduction of alveolar bone tissue, which are necessary in some clinical cases to ensure primary stability, was also analysed. However, the analyses showed that this combination leads not only to increased strain in the bone tissue, but also to higher stresses on the implant itself.
The main contribution of this work is a comprehensive evaluation of the influence of CT data resolution, segmentation threshold and clinical factors on the biomechanical behaviour of the implant and bone tissue. The knowledge gained can contribute to more accurate modelling, better planning of implant procedures and subsequently to an increase in their long-term success.