Novel Design and Optimization of Porous Titanium Structure for Mandibular Reconstruction

Abstract

A porous material is considered to be a potential material that can be used to repair bone defects. However, the methods of designing of a highly porous structure within the allowable stress range remain to be researched. Therefore, this study was aimed at presenting a method for generating a three-dimensional tetrahedral porous structure characterized by low peak stress and high porosity for the reconstruction of mandibular defects. Firstly, the initial tetrahedral porous structure was fabricated with the strut diameters set to 0.4 mm and a mean cell size of 2.4 mm in the design model space. Following this, the simulation analysis was carried out. Further, a homogenization algorithm was used for homogenizing the stress distribution, increasing porosity, and controlling peak stress of the porous structure by adjusting the strut diameters. The results showed that compared with the initial porous structure, the position of the large stress regions remained unchanged, and the peak stress fluctuated slightly in the mandible and fixation system with the optimized porous structure under two occlusions. The optimized porous structure had a higher porosity and more uniform stress distribution, and the maximum stress was lower than the target stress value. The design and optimization technique of the porous structure presented in this paper can be used to control peak stress, improve porosity, and fabricate a lightweight scaffold, which provides a potential solution for mandibular reconstruction.

Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery

“…Although some studies have shown that muscle strength returns to presurgery levels during the healing period following resection [71,106], others suggest that reduced muscle force may occur due to decreased chewing power after reconstruction surgery [22,26,41]. We believe, this topic needs more investigation since there is still a lack of information about post-operative muscle forces in patients especially, those with extensive mandibular defects [48,74]. Upon further review, we also found that a considerable number of studies implemented a simplified model of the TMJ, primarily using fixed or hinge joint configurations as discussed before.…”

“…In conclusion, while using bony implants, especially fibular flaps, is regarded as the gold standard in larger reconstructions, there is some general dissatisfaction amongst patient populations in terms of functionality and aesthetics [62]. Therefore, alternative solutions such as prosthetic implants have been proposed [27,74]. Furthermore, autogenous grafts impact the patient even more since there are two points of surgical intervention.…”

Computational Models and Their Applications in Biomechanical Analysis of Mandibular Reconstruction Surgery

“…Nevertheless, bone is a highly complex structure with different types of tissue (e.g., cortical or cancellous) and specific characteristics such as viscoelasticity and anisotropy [22,97], and simple modeling assumptions may not fully capture the intricate complexity of bone [95]. To account for this complexity, some studies [21] 2006 -✓ ---Tie et al [29] 2006 ✓ ----Schuller-Götzburg et al [30] 2009 ✓ ✓ --HA Wu et al (a) [31] 2012 ✓ ✓ ---Wong et al [23] 2012 --✓ --Jedrusik-Pawłowska et al [32] 2013 [33] 2013 -✓ --CI & PF Chang et al [34] 2013 [36] 2014 -✓ --CI & PF Bujtár et al [37] 2014 -✓ ---Narra et al [38] 2014 -✓ -CoT -Pinheiro and Alves [39] 2015 --✓ --Al-Ahmari et al [40] 2015 -✓ ---Jahadakbar et al [41] 2016 ✓ ✓ -CoT -Mehle et al [42] 2016 -✓ ---Park et al (a) [43] 2016 ✓ ✓ ---Dahake et al [44] 2017 --✓ --Nasr et al [45] 2017 -✓ ---Moiduddin et al (a) [46] 2017 [47] 2017 ✓ ✓ -FT -Luo et al [48] 2017 -✓ --RA Sanal et al [49] 2017 -✓ ---Seebach et al [24] 2017 ✓ ✓ ---Gutwald et al [50] 2017 -✓ -FT -Yoda et al [18] 2018 [52] 2018 ✓ ✓ ---Hoefert and Taier [53] 2018 -✓ ---Gao et al [ [64] 2021 ✓ ✓ ✓ --Koper et al [25] 2021 -✓ -CoT -Lang et al [22] 2021 ✓ ✓ -CoT & FT CA Kang et al [65] 2021 [74] 2022 --✓ --Shen et al [27] 2022 --✓ CoT -Jung et al [75] 2022 have adopted more sophisticated modeling techniques. Some of th...…”

“…Underloading resorption, equilibrium, apposition, and overloading resorption are the four phases of bone remodeling, [31] 2012 -✓ -----Ti Jedrusik-Pawłowska et al [32] 2013 [36] 2014 -✓ ----✓ Ti Bujtár et al [37] 2014 ------✓ Ti Narra et al [38] 2014 -✓ -----Ti6Al4V ELI Al-Ahmari et al [40] 2015 -✓ -----Ti6Al4V ELI Jahadakbar et al [41] 2016 [67] 2021 In conclusion, while using bony implants, especially fibular flaps, is regarded as the gold standard in larger reconstructions, there is some general dissatisfaction amongst patient populations in terms of functionality and aesthetics [62]. Therefore, alternative solutions such as prosthetic implants have been proposed [27,74]. Furthermore, autogenous grafts impact the patient even more since there are two points of surgical intervention.…”

A Novel Design Method of Gradient Porous Structure for Stabilized and Lightweight Mandibular Prosthesis

“…Based on previous studies [ 21 , 22 , 23 , 24 ], four structures with the same lattice size and different porosities were simulated to obtain the optimal lattice unit cell with a stronger bearing capacity. A functionally gradient scaffold optimization algorithm was proposed to control maximum stress and improve porosity, that is, a larger diameter is designed for high-stress struts and a smaller diameter for low-stress struts to reduce material wastage as much as possible while maintaining their performance.…”