Prosthodonic implications and effects of orthognathic surgery on oral functions in the patients with mandibular prognathism

正颌外科通常用于严重的下颌前突患者。在正颌外科的颌间固定中，由于易于确定节段的位置，通常使用夹板。在升支矢状劈开截骨术中，夹板的准确性影响节段的定位。夹板需要简单而准确的材料。在第一个研究中，我们考察了三种树脂(热固化、自固化和光固化)的制备时间和尺寸。实验结果表明，光固化树脂是正畸手术夹板的最佳材料。在升支矢状劈开截骨术中，咬肌与粗隆分离，从而可以改变咬肌的长度。此外，颌间固定约6周会导致咬肌明显萎缩。第二项研究的目的是检查这些手术对咬肌选择…的影响。更多的是肌电(EMG)。用机械敲击刺激双侧咬肌诱发下颌抽动反射时，测量双侧咬肌反应的起始潜伏期和峰潜伏期。对正常受试者和下颌前突患者手术前的这些潜伏期进行比较。这些潜伏期和波幅的变化也在手术后三天对患者进行了检测。结果显示，正常人与患者手术前的起搏潜伏期和波峰潜伏期无显著差异。在手术患者中，发现手术后这些潜伏期和波幅没有明显变化，尽管肌肉长度可能缩短，肌肉纤维萎缩，但无论是起始潜伏期还是峰期或波幅都没有变化。这一证据表明，肌梭可能不受肌纤维萎缩的影响。术后保持完好的伸展反射机制有助于患者尽快获得新的颌位和熟练的口腔功能。较少

Orthognathic surgery is generally employed for serious mandibular prognathism patients. In the intermaxillary fixation of orthognathic surgery, a splint is usually used due to the ease in determining the position of a segment. Accuracy of the splint effects the positioning of a segment in sagittal split ramus osteotomy. Simple and accurate materials are necessary for a splint. In the first study, we investigated the preparation time and dimensions of three resins (heat-curing, self-curing and light-curing). The test results are that the light-curing resin was the best material of the three for an orthognatic surgery splint. In sagittal split ramus osteotomy, the masseter muscle is detached from the masseric tuberosity so that the length of the masseter muscle may be changed. Furthermore, intermaxillar fixation of about 6 weeks causes the distinct atrophy of the masseter muscle. The purpose of the second study was to examine the influence of these operations on the masseter muscle elect … More romyographically (EMG). While the jaw jerk reflex was evoked by mechanical tap stimulation of the menton, the onset and peak latencies of the responses of the bi-lateral masseter muscles were measured. These latencies were compared between normal subjects and patients with mandibular prognathism before surgery. Changes in these latencies and amplitudes were also examined in patients on three different days after surgery. The results showed no significant difference in the onset and peak latencies between the normal subjects and patients before the surgery. In patients with the surgery, it was found that these latencies and amplitudes did not significantly change after the surgery.In spite of the probable decrease of muscle length and the atrophy of the muscle fibers, no change could be found in either onset and peak latencies or amplitude. This evidence suggests that the muscle spindles may not be influenced by the atrophy of the muscle fibers. The stretch reflex mechanism which remains intact after the surgery is helpful for the patients in acquiring a new jaw position and becoming skillful in oral functions as soon as possible. Less