Comparison of Stability of Resorbable and Titanium Fixation Systems by Finite Element Analysis After Maxillary Advancement Surgery

Abstract

In this study, three-dimensional modeling and finite element analysis were used to evaluate and compare the stability of Le Fort I osteotomy fixed with titanium and resorbable fixation systems under molar and incisor bite forces. A three-dimensional model of 5-mm advanced hemimaxilla was generated. Contact analyses between the upper and lower segments were prescribed. Two L-plates were inserted on this model via simulation. Displacement, principal stresses, and principal elastic strains were evaluated under 44-N, 125-N incisor and, 250-N molar bite forces. These results suggest that Le Fort I osteotomies fixed with titanium miniplates and screws were stable under all tested forces. However, in resorbable group, under incisor bite forces greater than 44 N, there is a great risk of plate fracture, screw deformation, and/or failure.

Characterization of load dependent creep behavior in medically relevant absorbable polymers

“…While the loads were chosen based on features of the stress-strain curve, they also represent a range of physiologic loading magnitudes that may be expected for clinical applications where absorbable medical devices are used. Such examples include fixation systems for maxillary osteotomies with forces in the range of approximately 30-300 N (Gerlach and Schwarz, 2002;Smit et al, 2008;Uckan et al, 2009) and rib fixation with applied forces of 50 N or less, (Marasco et al, 2010) as well as muscle contraction on suture with forces of 50 N or less (Burkhart, 2000), and ligament reconstruction with forces in the hundreds of Newtons (Escamilla et al, 2009(Escamilla et al, , 2010. Static creep experiments under 50 N were allowed to proceed for only 7 hours due to the slow rate of creep.…”

Development and testing of an absorbable spring for cranial expansion in rabbits

“…These materials have properties such as inertia, strength, and elasticity comparable to those of metals such as titanium alloys (Dhol et al, 2008;Uckan et al, 2009), with the added advantage of not requiring removal; this makes them useful in any setting where leaving hardware in indefinitely or removing it would increase morbidity.…”

Biomechanical Analysis of Reduction Malarplasty With L-Shaped Osteotomy

“…15 It simulates real physical systems by using the method of mathematical approximation to divide them into numerous smaller interrelated units. 16,17 This technique, which allows parametric representation and analysis of complex geometric and material property distributions, which occur in vivo and which normally are difficult to represent with other analytical or experimental techniques, 18 has been used successfully to predict failure loads and fracture patterns for bone structures. 19 It has the following advantages: it is noninvasive; the intensity of stress can be theoretically measured; the material properties of craniofacial structures can be assigned to the nearest one that possibly can simulate this environment in vitro; unseen regions such as the sinuses can be visualized graphically; the point of application, magnitude, and direction of a force can be varied to simulate clinical FIGURE 6.…”

“…The simple method of artificially dividing the bone tissue into cortical bone and cancellous bone and giving each of them a single elastic modulus and Poisson ratio is commonly used in current FE modeling process. 16,20Y25 It differs greatly from the actual anatomic structure and biomechanics conditions, although this study used the gray values that were obtained from actual CT scanning on each voxel, which then transformed with one-to-one correspondence into the apparent density value, elastic modulus, and Poisson ratio of each unit in the FE model. Thus, the material assignment is more accurately conducted.…”