Finite element analysis in mandibular advancement between Hunsuck/Epker and the novel modification of low Z plasty technique of BSSO

The recent modification of the BSSO technique was a novel modificationof the Low Z plasty (NM-Low Z) technique that main purpose is to reduce postoperativecomplications and ease the operative method. This surgical techniquechanges the horizontal osteotomy line more inferiorly than in the conventionalHunsuck–Epker (HE) method to be a more surgeon-friendly technique. The aim ofthis study was to compare the biomechanical behavior under simulated conditionsbetween the NM-Low Z and HE techniques on mandibular advancement. The modelswere investigated under physiological muscular and occlusal loads in 5 periods of theinflammatory stage (1-week post-operative), 2,4,6, and 8 weeks post-operative. Finiteelement analysis was used to analyze many parameters including stress distribution,elastic strain, and model displacement. Maximum equivalent Von Mises stresses wereobserved on the fixation system and bone. The elastic strain at the fracture siterepresented the optimal bone-healing capacity. The NM-Low Z model showed lowerstress than the HE models after 2 weeks of the post-operative stage onward. The elasticstrains observed in both models demonstrated within the normal range for bonehealing. The ranges of displacement for NM-Low Z model were less than that in HEmodels. In conclusion, the biomechanical study of the NM-Low Z technique can becompared to the conventional EH technique. The NM-Low Z technique could promotepost-operation skeletal stability by lowering stress on fixation and bone with lessdisplacement of the segment during bone healing periods.