PDF(Pubmed)
Abstract：
The aim of this study was to assess intra-arch mandibular dimensional changes that may occur during mouth opening using cone beam-computed tomography (CBCT). Fifteen patients in need of any type of treatment whose execution considered a pre- and post-CBCT assessment consented and were enrolled. CBCTs were taken with the following settings: 90 kV, 8 mA, field of view (FOV) 140 by 100 mm (height and diameter), Voxel size 0.25 mm (high resolution). The pre-CBCT was executed in the maximum mandibular opening (MO), while the post-CBCT was in the maximum intercuspation (MI). A thermoplastic stent with radiopaque fiducial markers (steel ball bearings) was fabricated for each patient. Measurements were made using radiographic markers between contralateral canines and contralateral first molars and between ipsilateral canines and first molars on both sides. Paired t-tests were performed to evaluate the difference between open and closed positions on these four measurements. In the MO position were registered a significative tightening of the mandible at the canine (-0.49 mm, SD 0.54 mm; p < 0.001) and molar points (-0.81 mm, SD 0.63 mm; p < 0.001) and a significative shortening of the mandible on the right (-0.84 mm, SD 0.80 mm; p < 0.001) and left sides (-0.87 mm, SD 0.49 mm; p < 0.001). Within the study limitations, mandibular flexure determined a significant shortening and tightening between maximum intercuspation to maximum opening positions. Mandibular dimensional changes should be considered in light of other patient factors in the treatment planning of implant positioning and long-span complete arch implant-supported fixed prostheses in order to avoid technical complications.
摘要：
这项研究的目的是使用锥形束计算机断层扫描（CBCT）评估在张口过程中可能发生的弓内下颌尺寸变化。15名需要任何类型治疗的患者，其执行考虑了CBCT前后评估的同意并入选。CBCT采用以下设置：90kV，8mA,视场（FOV）140x100mm（高度和直径），体素大小0.25毫米（高分辨率）。在最大下颌开口（MO）中执行CBCT前，而CBCT后处于最大切口（MI）。为每位患者制造具有不透射线基准标记（钢球轴承）的热塑性支架。使用对侧犬和对侧第一磨牙之间以及同侧犬和两侧第一磨牙之间的射线照相标记进行测量。进行配对t检验以评估这四个测量的打开和关闭位置之间的差异。在MO位置，记录了犬下颌骨的明显收紧（-0.49mm，SD0.54mm；p<0.001）和摩尔点（-0.81mm，SD0.63mm；p<0.001）和右侧下颌骨的显着缩短（-0.84mm，SD0.80mm；p<0.001）和左侧（-0.87mm，SD0.49mm；p<0.001)。在研究限制范围内，下颌弯曲确定了最大插入到最大打开位置之间的显着缩短和收紧。在植入物定位和大跨度完整足弓植入物支持的固定假体的治疗计划中，应根据其他患者因素考虑下颌尺寸变化，以避免技术并发症。
