青少年前牙骨性反(牙合)矫治的临床体会

目的：探寻临床对前牙骨性反He的有效治疗方法。方法：对18例安格Ⅲ类错He畸形采用单纯上颌前方牵引及上颌快速扩大与前方牵引联合治疗。结果：（1）两种方法对安格Ⅲ类错He畸形均有较好的治疗效果。（2）相对于单纯上颌前方牵引采用上颌快速扩大与前方牵引联合治疗常能取得更好的治疗效果。结论：上颌前方牵引及上颌快速扩大与前方牵引联合治疗是矫治青少年骨性反He有效的治疗方法。     

Vibratory Stimulation of the Masseter Musculature and Bite Force Discrimination

The purpose of this study was to compare the bite force discrimination of 12 normal subjects with and without disruption of proprioception from themasseter muscles, using vibratory stimulation. Bite force was measured using a strain gauge scale which permitted subjects to visually monitor when their bite force equalled a preset resistance. A resistance of 1000 gm was selected as the standard. The application of vibratory stimulation to the masseters involved a specially designed head holder and two 120 Hz vibrators by which contact pressure of 200 gm against both masseters could be maintained. During vibration, subjects required an average difference of 300 gm of resistance from the standard before they could detect a difference from a standard bite force of 1000 gm, whereas without vibration, only 196 gm were required. These results suggest that proprioception from the masseters is a factor in monitoring bite force discrimination.     

咬合力丧失影响大鼠牙周组织白细胞介素-6变化的研究

目的：探讨咬合力正常及丧失状态下,在鼠牙周细胞ＩＬ－６的动态表达,初探ＩＬ－６在牙周组织改建过程中的分子机理。方法：选用Ｗｉｓｔａｒ大鼠建立正常咬合力、咬合力丧失的动物模型,采用ＨＥ染色和免疫组化的方法,应用ＭＡＳ－２０００图像分析仪,对实验组和对照组各时间点牙周膜染色强度进行测量,观察其牙周形态变化以及牙周组织中ＩＬ－６蛋白表达的动态变化。结果：咬合力丧失引起牙周细胞中ＩＬ－６表达较正常咬合力时明显增强,同时观察到牙周膜结构紊乱、牙槽骨吸收。结论：咬合力丧失促使牙周组织产生ＩＬ－６明显增多且呈规律性变化,提示ＩＬ－６在咬合力影响牙周组织改建的过程中起着重要的调节作用。     

The Effect of Experimental Anesthetization of the Temporomandibular Joint Superior Cavity on Bite Force Discrimination

The purpose of this study was to determine whether bilateral experimental sensory impairment of the temporomandibular joints (TMJs), as induced by injecting 1.5 ml of two percent mepivacaine into the superior cavity of the TMJs would alter the subject's ability to discriminate among differences in their bite force. Assessment of bite force was measured isometrically, using the strain gauge scale, and isotonically, using the mechanical swing beam scale. Resistance forces of 500 and 1000 gms were selected as standards. For each task, subjects were given a series of paired resistance settings, one at a time, the first of each pair being the standard resistance and the second being a comparator resistance of some greater amount. Subjects reported whether biting against the comparator resistance was equal to, greater than, or less than the standard resistance. This procedure of paired comparisons was continued until the subject's threshold of discrimination (difference limen value) between two biting forces was established. The results revealed that the subject's ability to discriminate differences in their bite force, either isometrically or isotonically, was not significantly (p > 0.05) affected following anesthetization of the superior cavity of the TMJs. These findings suggest that the sensory receptors within the TMJ capsules are not significantly involved in the detection of forces that play a role in monitoring biting force.     

The Effect of a New Denture Adhesive on Bite Force Until Denture Dislodgement

PURPOSE: Denture adhesives are used to improve the denture retention and comfort of complete denture wearers. The purpose of this investigation was to establish the effect of a new denture adhesive on maximum bite force until denture dislodgement (BFDD) after adhesive application. MATERIALS AND METHODS: Fifteen denture-wearing patients (7 female, 8 male, mean age: 64 years) were involved in the study. The BFDD measurements were performed using a disposable gnathometer with a 1 to 10 scale. During one of the treatment sessions, the maximum BFDD with the pre-existing maxillary dentures using denture adhesive were measured. The measurements were also made at the baseline without adhesive and after the 1st, 2nd, 4th, and 6th hours following the application of the denture adhesive. The same procedure was applied to the new dentures about 2 weeks after the delivery of the dentures. The data were collected and statistically analyzed using ANOVA and Student's t-test. RESULTS: Consistent improvement was observed in BFDD when adhesive was used for all time intervals from the baseline (mean: 1.54 units, 3.20 units) to 6 hours (mean: 3.99 units, 4.60 units) for both pre-existing dentures (p= 0.003) and new dentures (p= 0.05), respectively. CONCLUSIONS: The results of this in vivo study suggest that the denture adhesive tested could effectively increase BFDD for up to 6 hours after application.     

The Influence of TMJ and Central Incisor Sensory Impairment on Bite Force Discrimination

In this study the authors temporarily altered sensation around the upper and lower front teeth as well as within the temporomandibular joints of 12 subjects. The purpose of the study was to determine the effect of such impairment by comparing bite force discrimination scores obtained under these experimental conditions with scores obtained under a normal non-anesthetized condition. A specially designed strain gauge scale was constructed for the measurement of incisor bite force. The subjects' abilities to discriminate differences in their biting forces were assessed under the following four experimental conditions: 1. Normal (no anesthetization).

2. Regional block to the upper and lower anterior teeth.

3. Bilateral regional block of the TMJs.

4. A combination regional block of the anterior teeth and the TMJs. Bite force discrimination was found to be significantly impaired (P<.05) only in the two conditions in which the teeth were anesthetized. These findings suggest that the periodontal ligament (PDL) provides sensory feedback relative to bite force discrimination whereas the TMJs do not.

     

咬合力丧失影响大鼠牙周组织中白细胞介素-6mRNA表达的研究

目的：初探IL－6 mRNA在牙周组织改建中的分子机理,方法：选用Wistar大鼠建立正常咬合力,咬合力丧失的动物模型,采用原位杂交方法,观察牙周细胞中IL－6mRNA表达的动态变化,结果：咬合力丧失引起牙周细胞中IL－6mRNA表达较正常咬合力时明显增强。结论：咬合力失,促使IL－6 mRNA明显增多,诱发了破骨过程,影响着牙周组织的改建。     

平面导板对正畸治疗中牙根吸收影响的临床研究

目的：探讨平面导板配合直丝弓矫治对牙根吸收的影响。方法：随机选择66例经过直丝弓矫治的成年非拔牙患者，其中33例配合使用平面导板治疗。治疗前后拍全口曲面断层片，分别测量2组治疗前后下颌4个切牙的牙根吸收等级，并经过计算机进行X^2检验。结果：2组正畸治疗后均有明显的牙根吸收，治疗前后牙根吸收等级有显著性差异（P〈0．01）。治疗后2组间牙根吸收等级也有显著性差异（P〈0．01）。结论：直丝弓配合平面导板矫治组较单独使用直丝弓矫治的牙根吸收更严重。     

On the Perception of Jaw Position and Bite Force by Subjects with Craniomandibular Disorders

This study investigated the sense of jaw position and the sense of bite force in subjects with symptoms of temporomandibular joint (TMJ) disorders. The results were compared with those of control experiments on symptom-free subjects. It was shown that: 1. Some subjects with signs of TMJ disorders showed deviant matching behavior when matching the magnitude of jaw separations to an imagined standard but not when matching to the remembered size of a standard gauge of 4.75 mm. These subjects also showed considerable fluctuation in their match. Moreover, values of imprecision of jaw position matches were greater in subjects with TMJ symptoms than in symptom-free subjects.

2. Some subjects with TMJ symptoms showed deviant matching behavior when matching to a 2-N and a 10-N but not to a 50-N standard. These subjects were also variable in their match.

3. Bruxism and nail biting correlated with these findings. Certain clinical implications are discussed.

     

Changes in Bite Force and Muscle Forces in the Upper Extremities After Counter Irritation

Abstract

Today, physical therapy is recognized as an effective, reversible, and conservative treatment for temporomandibular disorders (TMD). The purpose of this investigation is to explore the feasibility of utilizing counter irritation with ischemic pain at a remote site outside of the head and neck region as a method for restoring muscle force in a course of physical therapy. Twenty healthy asymptomatic female subjects were recruited for this study. The experiments were performed over two days, with the two experimental days randomly assigned to the experiment performed with or without counter irritation. The counter irritation was applied to the subject’s left hand using a submaximal effort tourniquet procedure. The maximal bite, finger-pinch, and handgrip forces were measured on the right side, and the results from the days with and without the counter irritation were compared. As a result, a significantly higher mean maximal bite force and a trend toward higher finger-pinch force were observed with the irritation than without the irritation, while there was no significant difference in the handgrip force. These findings indicate that counter irritation outside of the head and neck may be useful for increasing bite force, and may be applicable in the treatment of TMD for the restoration of masticatory muscle force.     

第三磨牙阻生致前牙及双尖牙区开的矫治

目的:通过1例第三磨牙阻生致前牙及双尖牙开的矫治,探讨开的矫治原则。方法:2006年于武汉大学口腔医学院正畸科就诊的1例因第三磨牙阻生致前牙及双尖牙开的患者,拔出4颗第三磨牙及一组双尖牙,通过MBT直丝弓矫治技术进行矫正。结果:患者的开得以矫正,面型改善明显,前牙覆覆盖正常,咬合关系良好。结论:在进行开的诊断和设计时,必须认真分析引起开的原因,选择合适的治疗方案。     

Bite force and masseter muscle electromyographic activity during onset of an isometric clench in man

The surface electromyogram (EMG) of the masseter muscle and interocclusal force were recorded in six human subjects during fast and slow clenches. The simple linear force/EMG relation that applies for steady bite-force levels was inadequate to explain their relationship under conditions of changing force: a second component of force, its rate of change, was necessary. EMG/force equations for fast and slow clenches were broadly similar. The rate of change factor may account for the apparent EMG/force lag observed in earlier studies.     

粘固式下颌联冠斜面导板治疗功能性前牙反(牙合)的临床效果

目的 研究粘固式下颌联冠斜面导板在治疗功能性前牙反He中的作用。方法 利用粘固式下颌斜面导板辅助固定矫正器对18例功能性前牙反He患者进行治疗，拍摄治疗前后头颅侧位定位片。结果 18例患者均在1月左右解除前牙反He，面型获得改善；其矫治原理和特点为：通过使上前牙唇倾、下前牙舌倾、下颌下旋，以解除前牙反He。结论 下颌联冠斜面导板用于功能性前牙反He，治疗简单，效果明显。     

腭裂引起反的前牵引与下颌髁突位置关系的初步研究

目的　评价应用口外弓加面具对唇腭裂继发骨性反牙合畸形进行早期阻断性治疗后 ,下颌骨髁突位置的变化。方法　对 8例患者治疗前和治疗 6个月的薛氏位片进行分析 ,比较颞下颌关节 (TMJ)前、上、后间隙的宽度。结果　治疗前后双侧TMJ的 3个间隙均无明显改变 (P >0 .0 5 )。结论　应用口外弓加面具作上颌骨前牵引后 ,未发现髁突位置的明显改变。