Customized 3D Allogenic Bone Blocks for Mandibular Buccal-Bone Reconstruction Increase Resistance to Tongue-Protrusion Forces: A Finite Element Analysis

Background. The impact of tongue protrusion forces on the formation of malocclusions is well documented in academic literature. In the case of bone dehiscence of the buccal wall in front of the lower frontal teeth, this process may be even more pronounced. Augmentation with 3D customized allogenic bone blocks (CABB) has been proposed as a potential solution for treating such defects. The objective was to assess the impact of bone block adjustment accuracy on the resistance of teeth to protrusion forces at various stages of alveolar bone loss. Methods: A finite element analysis (FEM) was conducted to ascertain whether augmentation with a CABB will result in increased resilience to tongue protrusion forces. Three-dimensional models of the mandible with dehiscenses were created, based on the dehiscences classification and modification proposed in the journal by the authors of regenerative method. The models feature a CABB positioned at three different distances: 0.1 mm, 0.4 mm, and 1.0 mm. The material parameters were as follows: bone (homogenous, isotropic, E = 2 GPa), teeth (E = 20 GPa), periodontal ligament (E = 0.44 MPa), and membrane between bones (E = 3.4 MPa). A tongue protrusion force within the range of 0–5 N was applied to each individual frontal tooth. Results: The use of an CABB has been shown to positively impact the stability of the teeth. The closer the bone block was placed to the alveolar bone, the more stable was the result. The best results were obtained with a ¼ dehiscence and 0.1 mm distance. Conclusions: The protrusive forces produced by the tongue might not be the biggest one, but in a presence of the bone loss they might have serious results. Even shortly after the surgery, CABB has a positive impact on the incisor resilience.