Investigation of a Modified Novel Technique in Bilateral Sagittal Splitting Osteotomy Fixation: Finite Element Analysis and In Vitro Biomechanical Test

Abstract

Purpose. To evaluate the biomechanical properties of the modified novel 2-hole monocortical plate fixation (2HMCPf) and traditional 4-hole monocortical plate fixation (4HMCPf) techniques in bilateral sagittal splitting osteotomy (BSSO) synthesis using a finite element analysis (FEA) and an in vitro biomechanical test with the application of a shearing loading force on a sawbone mandible model. Materials and Methods. A three-dimensional mandible models were generated using the geometry obtained from the computerized tomography image of a sawbone mandible. Plates and screws were generated and combined with the mandible in a CAD environment. The 2HMCPf and traditional 4HMCPf techniques for BSSO osteosynthesis were then analyzed under the occlusal load using the FEA. An in vitro biomechanical test was executed to verify the result of FEA. The force on fixation failure and pattern of failure were recorded. Results. The results revealed that the von Mises Stress on the mandible cortical bone (75.98 MPa) and the screw/plate (457.19 MPa) of the 2HMCPf group was lower than that of the 4HMCPf group (987.68 MPa, 1781.59 MPa). The stress concentrated on the central region of the 4HMCPf group and the distal set of the 2HMCPf group. In vitro study using the sawbone mandible model showed mechanical failure at the region of the proximal segment near the osteotomy site with the 4HMCPf group (average 32.198 N) but no failure on the fixation sites with the 2HMCPf group. Instead, the mandible sawbone fractured on the condyle neck region (average 44.953 N). Conclusion. From the biomechanical perspective, we proved that the 2HMCPf method was able to withstand a higher shearing loading force than the 4HMCPf fixation method in BSSO osteosynthesis.

Biomechanical Effects of Different Miniplate Thicknesses and Fixation Methods Applied in BSSO Surgery Under Two Occlusal Conditions

“…Moreover, when only a single miniplate (upper or lower) is implanted, the bone at the screw implantation sites has a higher stress value near the cutting edges of the proximal and distal segments. This finding is compatible with previous researches [13][14][15]. Hence, a screw with increased diameter or length could be considered at those sites to increase the contact area with the bone and reduce the stress there.…”

“…Finite element analysis (FEA) has been proven to be a powerful tool for analyzing the biomechanics of maxillofacial surgery [11]. Many studies have used FEA to analyze the different types and positions of rigid fixations and the strain and stability on the miniplates and mandibles [12][13][14][15][16][17][18][19]. Among studies that have used FEA to analyze the biomechanics of BSSO, most of them explored different rigid fixation methods with different plate designs and positions.…”

“…Therefore, the biomechanics of miniplate thickness is worth exploring. In addition, some studies using FEA have analyzed the biomechanics of multiple miniplates and have designed the miniplate to be implanted at a lower position (below the middle portion or near the inferior border of the mandible) [12][13][14][15].…”

Biomechanical Evaluation of Seven Fixation Methods for Sagittal Split Ramus Osteotomy with Four Advancement Levels by Finite Element Analysis

“…The biomechanical characteristics of different fixation methods in SSRO have been explored in previous studies ( 6 – 10 , 12 , 13 , 17 , 19 – 23 ); however, these studies focused mainly on small advancements ( 7 , 9 , 10 , 13 , 19 , 22 , 23 ). In clinical practice, large advancement in SSRO is not uncommon to correct severe mandibular deformity and improve the airway in OSA ( 17 , 18 ).…”

Titanium or Biodegradable Osteosynthesis in Maxillofacial Surgery? In Vitro and In Vivo Performances

“…Although it would be of high clinical value to determine the exact cut-off value of the transition from load-sharing to load-bearing osteosyntheses, this is currently unknown. Since the mandible is exposed to considerably higher biomechanical forces compared to the maxilla [ 1 ], load-bearing osteosynthesis of the mandible requires even higher mechanical properties of the used osteosynthesis system compared to load-bearing osteosynthesis of the maxilla or load-sharing osteosynthesis of the mandible [ 172 , 173 ]. Furthermore, as bone healing progresses, the forces will be shared by the osteosynthesis system and the underlying healing bone.…”