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

正颌手术通常用于严重的下颌前突患者。在正颌手术的上颌间固定中，由于易于确定节段的位置，通常使用夹板。夹板的准确性影响矢状分叉支截骨术中节段的定位。简单准确的材料是制作夹板的必要条件。在第一项研究中，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。测试结果表明，光固化树脂是三种材料中用于正颌手术夹板的最佳材料。在矢状分叉支截骨术中，将咬肌与粗隆分离，从而改变咬肌的长度。此外，大约6周的颌间固定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肌的影响。在机械轻叩刺激颏部诱发下颌抽搐反射的同时，测量了双侧咬肌反应的起始和峰值潜伏期。这些潜伏期在正常受试者和术前下颌前突患者之间进行比较。这些潜伏期和振幅的变化也在手术后三天的不同患者中进行了检查。结果显示，正常受试者与术前患者的发作和峰值潜伏期无显著差异。在接受手术的患者中，发现这些潜伏期和振幅在手术后没有明显改变。尽管肌肉长度可能减少，肌纤维萎缩，但在起始和峰值潜伏期或振幅方面均未发现变化。这一证据表明肌梭可能不受肌纤维萎缩的影响。术后保持完整的牵张反射机制有助于患者尽快获得新的颌位，熟练掌握口腔功能。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