骨研究ジャーナル
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概要

Comparing Peak Load Capacity between Bicortical Screws and 3D Plates in Human Cadaveric Sagittal Split Ramus Osteotomy

ジャン・ジャン*

Study design: Skeletal relapse following mandibular advancement using the Sagittal Split Osteotomy (SSO) is associated with the degree of advancement and method of fixation. Objective: The study purpose is to compare the biophysical properties of two fixation techniques for the SSO advancement.

Methods: This cadaveric in vitro study was conducted at a single tertiary care centre. Paired hemimandibles underwent SSO with 10 mm of advancement then fixated using two techniques. Group 1 used a single 3D ladder miniplate and group 2 used a miniplate and two bicortical screws (hybrid technique). Hemimandibles were loaded in the first molar region using an Instron mechanical testing unit. The primary predictor variable is the fixation method. The outcome variables were peak load in Newtons (N) defined as the load at which permanent deformation started, displacement value at peak load, and load (N) necessary for a specific amount of displacement. Donor demographic and anatomic variables were age, gender, dental status, mandibular body height, ramus width, and thickness of mandibular angle. Descriptive statistics and paired two-sided t-tests were performed with P-value ≤ 0.05.

Results: The fifteen human mandibles were 53% male and 47% female with mean age of 82.2 years (range 78-92 years). Mean ± Standard Deviation (SD) peak load was 75.3 ± 43.3 N for 3D ladder plate technique and 116.2 ± 57.9 N for the hybrid technique, the difference of means (group 1–group 2) was -40.9 ± 73.3 N (T-value=2.15, P-value=0.048).

Conclusion: The hybrid technique showed a significantly greater peak load compared to the 3D plate for the SSO advancement, suggesting the former may provide superior resistance to relapse in the clinical setting. This cadaveric model can be utilized for additional clinical questions and be a bridge between synthetic in vitro models and clinical studies.