Biomechanical evaluation of maxillary Lefort Ι fracture with bioabsorbable osteosynthesis internal fixation

Abstract

The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.

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

“…Several studies assessed the mechanical forces surrounding osteosyntheses applied to maxillofacial fractures [ 157 , 158 , 159 , 160 , 161 , 162 , 163 ], osteotomies [ 164 , 165 ] and reconstructions [ 166 ], so that the minimally required mechanical properties of an osteosynthesis system can be estimated. After maxillofacial trauma, the reported bite force increases up to 64 N by the second postoperative fracture fixation day, 92 N after 1 week, 187 N after 4 weeks, and up to 373 N at the 3-month follow-up [ 157 ].…”

“…Within the limitations of finite element analyses (e.g., assuming the masticatory forces are fixed), three-dimensional analyses indicated that the biomechanical stresses surrounding osteosynthesis systems remain far below the threshold of their ultimate strength of both biodegradable and titanium osteosynthesis systems [ 163 , 172 , 182 , 183 ]. In addition, the empirical evidence of fracture [ 19 ] and osteotomy [ 184 ] osteosyntheses shows that the efficacy of titanium and biodegradable osteosyntheses is similar (e.g., absence of malunion), indicating that the less favorable mechanical properties of biodegradable osteosynthesis are still sufficient to achieve similar healing outcomes.…”

Biodegradable and titanium osteosynthesis in maxillofacial surgery

“…Several studies assessed the mechanical forces surrounding osteosyn-theses applied to maxillofacial fractures [146][147][148][149][150][151][152] , osteotomies 153,154 and reconstructions 155 . After maxillofacial trauma, the reported bite force increases up to 64 N by the second postoperative fracture follow-up 146 .…”

“…surrounding (biodegradable) osteosynthesis systems remain far below the threshold of their ultimate strength 14,34,152,159 . In addition, the systematic reviews of fracture and osteosyntheses is similar (e.g., absence of malunion) indicating that the less favourable similar healing outcomes (Chapters 2 and 3).…”

“…A previous -3% in the elastic modulus after only 10 cycles 160 . Furthermore, stress concentration due to long-term loading of biteforce and muscle traction on the osteosynthesis were shown to be important factors that lead to osteosynthesis system fracture 152 . In addition, since biodegradable copolymeric systems undergo bulk degradation, thereby decreasing their mechanical properties with time 41,126 , the mechanical properties of different biodegradable systems during degradation should be assessed and compared.…”