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1.
Objectives: The purpose of the present study was to compare craniofacial morphology and bite force of bruxist patients with signs and symptoms of temporomandibular disorders. Method: Fourteen subjects with sleep bruxism and 14 healthy subjects participated. The signs and symptoms of the temporomandibular disorders were identified according to the Craniomandibular Index (CMI). Maximum bite force was measured using strain-gage transducers. Lateral cephalometric films were taken, and linear and angular measurements were performed. Results: Bite force between bruxist and non-bruxist females was not significant, whereas males with bruxism revealed higher bite forces. None of the linear and angular measurements differed significantly between bruxist and non-bruxist males. However, higher mandibular corpus length and anterior cranial base length, and lower gonial angle were observed in bruxist females compared to non-bruxist females. Negative correlation between bite force and CMI values was found in both genders. Discussion: Bruxist females had higher CMI values than bruxist males, which could lead to relatively lower bite forces. 相似文献
2.
ObjectiveThe aim of this study was to evaluate whether vertical facial patterns influence
maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity,
and medial mandibular flexure (MMF). Material and MethodsSeventy-eight dentate subjects were divided into 3 groups by Ricketts''s analysis:
brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar
region was bilaterally measured with a force transducer. The electromyographic
activities of the masseter and anterior temporal muscles were recorded during
maximal voluntary clenching. Medial mandibular flexure was calculated by
subtracting the intermolar distance of maximum opening or protrusion from the
distance in the rest position. The data were analyzed using ANOVA followed by
Tukey''s HSD test. The significance level was set at 5%. ResultsData on maximum occlusal force showed that shorter faces had higher occlusal
forces (P<0.0001). Brachyfacial subjects presented higher levels of masseter
electromyographic activity and medial mandibular flexure, followed by the
mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed
significantly lower electromyographic temporalis activities (P<0.05). ConclusionWithin the limitations of the study, it may be concluded that maximum occlusal
force, masticatory muscle activity and medial mandibular flexure were influenced
by the vertical facial pattern. 相似文献
3.
Nocturnal bite force during sleep associated bruxism was measured in 10 subjects. Hard acrylic dental appliances were fabricated for the upper and lower dentitions of each subject. Miniature strain-gauge transducers were mounted to the upper dental appliance at the right and left first molar regions. In addition, thin metal plates that contact the strain-gauge transducers were attached to the lower dental appliance. After a 1-week familiarization with the appliances, nocturnal bite force was measured for three nights at the home of each subject. From the 30 recordings, 499 bruxism events that met the definition criteria were selected. The above described system was also used to measure the maximum voluntary bite forces during the daytime. The mean amplitude of detected bruxism events was 22.5 kgf (s.d. 13.0 kgf) and the mean duration was 7.1 s (s.d. 5.3 s). The highest amplitude of nocturnal bite force in individual subjects was 42.3 kgf (15.6-81.2 kgf). Maximum voluntary bite force during the daytime was 79.0 kgf (51.8-99.7 kgf) and the mean ratio of nocturnal/daytime maximum bite force was 53.1% (17.3-111.6%). These data indicate that nocturnal bite force during bruxism can exceed the amplitude of maximum voluntary bite force during the daytime. 相似文献
4.
ObjectiveThe aim of this study was to evaluate the maximal bite force (MBF), electromyographic (EMG) activity and thickness of the masseter, anterior part of the temporalis and sternocleidomastoid (SCM) muscles in a group of young adults with and without temporomandibular disorders (TMDs). DesignNineteen individuals comprised the TMD group (6 males/13 females, aged 25.4 ± 3.8 years), classified based on the Research Diagnostic Criteria for TMD (RDC/TMD), and 19 comprised the control group (6 males/13 females, aged 24.1 ± 3.6 years). The MBF was determined with a transducer placed between the dental arches at the first molars level (N). The muscles were evaluated bilaterally at rest and during maximal voluntary clenching (MVC) by assessing EMG activity and performing ultrasonography (USG). The mean values of these measures for both sides of the mouth were used. The normality of the distributions was assessed by the Shapiro–Wilks test. Variables between groups and genders were compared using two-way factorial ANOVA test and correlated using the Spearman coefficient ( α = 0.05). Unpaired t test was used to compare variables between TMD subgroups. Logistic regression analysis was used to identify the variables associated with the presence of TMD. ResultsMBF, EMG and USG data were similar among clinical groups and among TMD subgroups. The thickness of masseter and SCM muscles in the relaxed and clenching states were significantly higher in males than females. On the other hand, the EMG of the temporalis muscle in the rest state was significantly higher in females than males. Additionally, the MBF was positively correlated with the USG characteristics of masseter and SCM muscles, as well as with the EMG activity of masseter and temporalis muscles in the TMD group. In this group, there was also a positive correlation between the thickness of the masseter muscle and its activity. On the other hand, the thickness of the SCM muscle was negatively correlated with its activity. A lower MBF was independently associated with the presence of TMD. ConclusionsSubjects with TMD exhibited similar values of MBF, thickness and electrical activity of masticatory and cervical muscles when compared with controls; positive correlations observed between these variables may suggest a muscular alteration in TMD patients and a co-activation of masticatory and cervical muscles during mandibular movement. This fact may also be confirmed by the negative association between bite forces and presence of TMD. 相似文献
5.
The bite force of 51 twelve-year-old bruxists was compared with that of a control group of the same age, in order to establish whether bruxism affects bite force and whether there is any connection between the degree of tooth abrasion and bite force. Criteria for bruxism were bruxo facets in the bite and, in the same children, teeth-grinding at the time of examination. No differences in bite force values for bruxists and non-bruxists were found for either very light bite or maximum bite. One group with dentine facets had a higher bite force value for very light bite than the children with enamel facets. Otherwise there was no difference between the various facet groups regarding the bite force produced. 相似文献
6.
目的探讨功能性矫治器对咀嚼肌生物力学特性的影响及其临床意义。方法选用30只生长期Wistar雄性大鼠,戴功能性上颌平面导板活动矫治器4周后,应用力学的测试方法对其嚼肌、二腹肌前腹及翼外肌生物力学特性的改变进行定量分析。结果咀嚼肌收缩性质发生了明显变化:嚼肌收缩速度加快,收缩张力增强;二腹肌前腹收缩速度变慢,收缩张力增强;翼外肌的收缩张力明显减弱。结论本项实验表明,功能性矫治器是通过改变咀嚼肌及二腹肌的生物力学特性来促进颌骨的生长改建,达到功能性颌骨矫形目的 相似文献
7.
ObjectiveThe purpose was to evaluate the effect interocclusal appliance therapy on bite force (BF), sleep quality and salivary cortisol levels in adults with SB diagnosed by polysomnography. As a secondary aim, signs and symptoms of temporomandibular dysfunction (TMD) were evaluated. DesignForty-three adults (19–30 y/o) were divided into two groups: experimental group (G SB), composed of 28 subjects with SB, and control group (G C), without SB and TMD (n = 15). G SB was treated with stabilization interocclusal splint and evaluated at time intervals: before (baseline), one month (T1) and two months (T2) after therapy began, to collect data related to BF, sleep quality (Pittsburgh Sleep Quality Index), salivary cortisol levels and TMD. G C was also examined three times and received no therapy. Data were analysed by means of normality tests, t-test/Mann-Whitney and One-way ANOVA repeated measures (Tukey post-test). Two-way ANOVA test for repeated measures was applied to verify the effect time*group interaction on the variance of each dependent variable (α = 0.05). ResultsG SB showed an increase in BF and a positive effect on muscular symptomatology, range of mandibular movements and sleep quality; in G C these parameters did not differ. Cortisol concentration decreased between baseline and T1 in G SB (F (1,31) = 4.46; test power = 62%; p = 0.017). The variance observed for BF, TMD and sleep quality among time points was dependent on the group (moderate effect size: partial Eta square >0.16; test power >80%). ConclusionsThe results suggested that short-term interocclusal appliance therapy had a positive effect on BF, temporomandibular symptomatology, sleep quality and salivary cortisol levels in adults with SB. 相似文献
9.
Basic neurophysiological mechanisms for sleep bruxism remain unknown. Analyses of masseter muscle activity during sleep in guinea pigs have shown that the duration and activity of masseter bursts differ between non-rapid eye movement (NREM) and rapid eye movement (REM) sleep and that some repetitive burst episodes do occur. Furthermore, masseter bursts occurred in association with a transient heart rate increase. These results suggest that various patterns of masseter bursts occur in association with transient arousal activity during sleep in guinea pigs. 相似文献
11.
The masticatory muscles differ in their fiber type composition. It can therefore be expected that their electromyographic (EMG) power spectra will differ during the performance of different bite force tasks. In the present study, surface EMG activity was picked up from the masseter and from the anterior and posterior temporalis muscles of nine adult subjects. At a bite force level as low as 25 N, the mean power frequency (MPF) values of the posterior temporalis were significantly lower than those of the masseter and anterior temporalis. The MPF values of the masseter muscles decreased with an increase of bite force magnitude, whereas the MPF values of the anterior and posterior temporalis did not change significantly. The MPF values were significantly influenced by the direction of bite force. The observed changes of MPF are possibly related to the recruitment of different fiber types, and support the concept that the masticatory muscles behave heterogeneously. 相似文献
12.
Abstract— Bite force and activity in temporal and masseter muscles during biting and chewing were recorded in 19 control subjects and 23 subjects with symptoms and signs of functional disorders of the craniomandibular system. The entire group comprised 13 men and 29 women, 14–63 yr of age. Maximal unilateral bite force was 480 Newton (N) in control subjects and 387 N in patients, with corresponding bilateral values of 347 N and 230 N. At predetermined levels of contraction, temporalis and masseter activity were linearly related. Correlations of bite force and activity in short static contractions were significant with respect to unilateral, but not to bilateral force measurements. Only in the masseter muscle was strength of dynamic contractions during chewing significantly correlated to bite force. With the present method it was demonstrated that unilateral bite force is a simple clinical indicator of mandibular elevator strength as a whole, but inadequate to disclose asymmetric conditions. During isometric contraction, relative strength of electromyographic activity fairly accurately imaged the output of mechanical activity. 相似文献
13.
Knowledge about how Temporomandibular Disorder (TMD) pain patients regulate masticatory function is still unclear. To investigate the effect of experimental jaw muscle pain as well as texture and size of food on mastication, twelve healthy participants (30.6 ± 7.5 years old) participated in this study. Experimental pain was induced by an infusion of 0.5 M monosodium glutamate (MSG) with isotonic saline (IS) serving as a control. After the infusions, the Jaw Functional Limitation Scale (JFLS) and Pain Catastrophizing Scale (PCS) were filled out. Electromyographic (EMG) activity in the masseter and temporalis muscles, jaw movements and bite force, which was measured by a customized intra-oral device, were recorded simultaneously during mastication of three different types of food. Pain was scored continuously on a visual analog scale. The results demonstrated a trend towards a decrease in the impulse of the bite force, as well as a significant decrease in EMG activity of the masseter muscle during the first five masticatory cycles, in the MSG session. Also, MSG induced increased JFLS and PCS scores compared with IS. On the other hand, the results suggested that the applied levels of pain may not change habitual masticatory movements. This study has revealed that a clinically relevant level of pain in the masseter muscle has only minor impact on the performance of mastication, probably due to a lack of exacerbation of pain during function. In future studies of jaw muscle function during painful conditions, it is important to include patient-based reports of functional limitation and emotional distress. 相似文献
14.
Occlusal overload during sleep is a significant clinical issue that has negative impacts on the maintenance of teeth and the longevity of dental prostheses. Sleep is usually viewed as an ‘out-of-functional’ mode for masticatory muscles. However, orodental structures and prostheses are not free from occlusal loads during sleep since masticatory muscles can be activated at a low level within normal sleep continuity. Thus, an increase in masticatory muscle contractions, by whatever the cause, can be associated with a risk of increased occlusal loads during sleep. Among such conditions, sleep bruxism (SB) is a type of sleep-related movement disorders with potential load challenge to the tooth and orofacial structures. Patients with SB usually report frequent tooth grinding noises during sleep and there is a consecutive increase in number and strength of rhythmic masticatory muscle activity (RMMA). Other types of masticatory muscle contractions can be non-specifically activated during sleep, such as brief contractions with tooth tapping, sleep talking, non-rhythmic contractions related to non-specific body movements, etc.; these occur more frequently in sleep disorders. Studies have shown that clinical signs and symptoms of SB can be found in patients with sleep disorders. In addition, sleep becomes compromised with aging process, and a prevalence of most sleep disorders is high in the elderly populations, in which prosthodontic rehabilitations are more required. Therefore, the recognition and understanding of the role of sleep disorders can provide a comprehensive vision for prosthodontic rehabilitations when prosthodontists manage complex orodental cases needing interdisciplinary collaborations between dentistry and sleep medicine. 相似文献
16.
PurposeThe aim of this study was to evaluate the correlation between sleep bruxism (SB) frequency and serotonin transporter (SERT)-driven serotonin (5-HT)-uptake in platelets. MethodsSubjects were dental trainee residents and faculty members of Okayama University Hospital who were aware of having severe or no SB. SB frequency was assessed for 3-consecutive nights by a self-contained electromyographic detector/analyzer, which indicated individual SB levels as one of four grades (score 0, 1, 2 and 3). Subjects were classified as normal control (NC) when SB scores indicated only 0 or 1 during the 3 nights, or as severe SB for scores 2 or 3. Those subjects whose scores fluctuated from 0 to 3 during the 3 nights were omitted from further analysis. Fasting peripheral venous blood samples were collected in the morning following the final SB assessment. Amounts of SERTs proteins collected from peripheral platelets were quantified using ELISA, and SERTs transport activity was assessed by uptake assay using [ 3H]-5-HT. ResultsThirteen severe SB subjects and 7 NC subjects were eligible. Gender distribution, mean age, 5-HT concentration and total amounts of SERT protein in platelets showed no significant differences between NC and severe SB ( p = 0.85: Chi-squared test; p = 0.64, 0.26, 0.46: t-test). However, [ 3H]-5-HT uptake by platelets was significantly greater in NC compared to severe SB subjects (12.79 ± 1.97, 8.27 ± 1.91 fmol/10 5 platelets/min, p < 0.001, t-test). ConclusionThe results of this pilot study suggest a possible correlation between peripheral platelet serotonin transporter uptake ability and SB severity. 相似文献
17.
目的 :研究重度牙齿磨耗 (TW )患者咀嚼肌的肌电活动 ,探讨不同类型牙合磨耗患者咀嚼肌受损的肌电表现。方法 :以 15例中老年重度牙齿磨耗患者为研究对象 ,通过肌电图仪 (EMG)测试下颌姿势位和牙尖交错位最大紧咬时颞肌前束 (TA)、咬肌 (MM )、二腹肌前腹 (DA )的肌电幅值 ;并以 8例正常牙合患者的咀嚼肌肌电幅值作为对照。结果 :姿势位时 ,磨耗Ⅰ、Ⅱ、Ⅲ组患者TA、MM、DA的平均肌电幅值高于对照组 ,TA、MM的肌电幅值增高显著大于对照组 (P <0 .0 1) ;ICP最大紧咬时 ,Ⅰ、Ⅱ、Ⅲ组患者TA、MM、DA平均肌电幅值降低 ,MM、DA肌电幅值与对照组比较有显著性差异 (分别为P <0 .0 1,P <0 .0 5 )。结论 :牙齿磨耗患者有肌紧张存在 ,Ⅲ型磨耗导致的不均匀接触对咬肌的损伤较大 相似文献
18.
Objectives: To confirm the relationship between sleep bruxism (SB) and autonomic nervous (AN) activities to elucidate SB physiology. Methods: Subjects included 11 healthy males (mean age, 24.7 ± 2.3 years). These data were recorded in the sleep laboratory using a system composed of a two-axis accelerometer, an infrared camera, electroencephalography, electromyography, and electrocardiography. Time lapse analysis confirmed correlations between AN activity and SB events during sleep in subjects. Relationships between SB strength and length and AN activity were evaluated. Results: Sympathetic nerve (SN) and parasympathetic nerve (PSN) activities occurred significantly in 93.3% of cases (p < 0.01), with similar predictable patterns during SB. Furthermore, SB length and SN activity in seven of the subjects (four subjects, p < 0.05; three subjects p < 0.01), and PSN and SB muscle activities (% maximum voluntary contraction) in five subjects (four subjects, p < 0.05; one subject, p < 0.01) were significantly correlated. Discussion: The authors believe that SB is closely related to SN as well as PSN activities and may control the AN system. 相似文献
19.
AimTo investigate effect of capsaicin-evoked masseter-muscle pain on intramuscular blood-flow (BF) at rest and during contractions. MethodsEight healthy men (22-31 years) participated. BF was measured with Laser Doppler (Moor Instruments, UK) using a single-fibre probe inserted into the right masseter. Three BF probes were attached to the skin above right and left masseter and the right-middle finger. Subjects performed 30 s isometric contractions at 5%, 15%, and 25% of maximal voluntary contraction. After the contractions, capsaicin (0.1 mL, 100 μg/mL) was injected into the right masseter close to the fibre probe. When the pain sensation had disappeared, the series of submaximal contractions were repeated. BF data were sampled continuously, processed in 10 s bins, and analyzed with repeated-measures ANOVAs. ResultsIntramuscular BF significantly increased immediately after capsaicin injection ( P < 0.050) and rapidly (30 s) decreased to pre-injection values. A significant increase in cutaneous BF above the right masseter was observed ( P < 0.050) and lasted for 10 min, while a significant BF decrease in the finger ( P < 0.050) was observed. The contractions were associated with increases in intramuscular BF before and after the injection ( P < 0.022) and the contraction levels were also associated with increase in intramuscular BF before injection ( P = 0.008) but not after injection ( P = 0.314). ConclusionsThis study demonstrated BF increased by muscle contraction but failed to show effects of contraction levels on BF in a muscle exposed to nociceptive stimuli. Neurogenic inflammation in muscles could possibly be mediated via antidromical effects and local release of vasoactive substances. The decreased BF in the finger could be due to involvement of central regulatory mechanisms. 相似文献
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