Correlation between mandibular morphology and masticatory muscle thickness in normal occlusion and mandibular prognathism

Kim, Sang Woo; Kim, Chul‐Hwan

doi:10.5125/jkaoms.2020.46.5.313

Cited by 9 publications

(5 citation statements)

References 22 publications

(21 reference statements)

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“…The signi cant correlation between movement velocity and intervertebral disc herniation had been described before [36], and the improvement in opening/closing velocity was used to evaluate the e cacy of myorelaxation therapy on TMD [37]. There were signi cant differences in opening velocity for the types of muscle bres between the sexes [38,39], and males had a stronger lateral pterygoid muscle activity than females [40]. This can explain the reason for faster MOV and AOV in males than in females in healthy subjects.…”

Section: Discussionmentioning

confidence: 88%

Comparative analysis of myoelectric activity and mandibular movement in healthy and temporomandibular disorder subjects

Xiaojie,

Yiling,

Honglei

et al. 2024

Preprint

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Objectives: Temporomandibular disorders (TMD) are one of the leading causes of craniofacial pain, and a high incidence of TMD in young adults has been reported. Previous studies have used surface electromyography (sEMG) and mandibular kinematic analysis to diagnose TMD. This study aimed to provide normal reference values of sEMG and mandibular kinematics in Chinese young adults, compare the sex differences and assess the diagnosis value of these indices. Materials and methods: This was an observational study that 90 healthy young adults (49 women and 41 men) with individual normal occlusion were strictly selected by diagnosis standard, and 26 TMD patients with disc displacement (13 with reduction and 13 without reduction) were recruited. The sEMG signals of the anterior temporalis (TA), masseter (MM), and sternocleidomastoid and digastric were recorded in the mandibular postural positions (MPP) and during maximal voluntary clenching (MVC) with K7 electromyograph. Mandibular kinematics, including maximum opening and opening/closing velocities, were assessed by K7 kinesiograph. Results: In healthy subjects, the sEMG reference values ranged from 3.0 to 4.3 μV in the MPP. The sEMG values during MVC, maximum opening, and opening velocity were significantly higher in males than in females, and also these indices showed good diagnostic efficiency for articular TMD. Conclusions: Reference values and sex differences in sEMG and mandibular kinematics in healthy subjects were determined. Compared with them, TMD patientsshowed significantly lower myoelectric activity during maximal biting and restricted mouth opening range and velocity, which may assist in TMD diagnosis. Clinical relevance: By analyzing sEMG of masticatory muscle and mandibular kinematics data from healthy Chinese young adults and TMD patients with disc displacement, this study evaluated the sex difference and diagnosis value of these indices for TMD. Clinical Trial Registration ID: NCT06372769

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Section: Discussionmentioning

confidence: 88%

Comparative analysis of myoelectric activity and mandibular movement in healthy and temporomandibular disorder subjects

Xiaojie,

Yiling,

Honglei

et al. 2024

Preprint

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show abstract

“…The facial and masticatory musculature is of utmost value in the causation and management of malocclusions and craniofacial deformities, as well as for the retention of achieved orthodontic treatment. 18 Forces of soft tissue and associated musculature act on dentition exerting variable magnitude and duration of forces during rest and activity. Resting postural forces of oral musculature are continuous and are of long duration.…”

Section: Discussionmentioning

confidence: 99%

Influence of Resting Tongue Posture on Mandibular Arch Width and Vertical Dimensions of Face

2023

JPMI

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Objective: To evaluate the influence of tongue posture on the arch width of the mandible and the facial proportions in the vertical dimension.Methodology: A cross-sectional analysis was carried out utilizing lateral cephalograms and dental molds from 120 participants (45 males, 75 females). The participants were classified into three categories based on the dimensions of their vertical facial structure: Normodivergent, Hyperdivergent, and Hypodivergent. The posture of the tongue was ascertained by measuring the distance from the tongue to the palate using the technique introduced by Graber and colleagues. The widths of the mandibular dental arches were assessed using the study molds. Differences among the groups were evaluated using one-way ANOVA. Relationships between mandibular arch widths and six distinct tongue-to-palate measurements were investigated using Pearson's correlation. A p-value of ≤ 0.05 was deemed to indicate a statistically significant result. Results:The comparison of the tongue to palate distances (D1, D2, and D3) at 0, 30, and 60 degrees among study groups showed statistically nonsignificant differences, however, the tongue to palate distances (D4, D5, and D6) showed statistically significant differences amongst all groups. Statistically significant differences were found in intercanine and intermolar width among the three study groups. The correlation of tongue posture with mandibular intercanine width and intermolar width at all six tongue-to-palate distances was weak. Conclusion:In hyperdivergent patients, the tongue posture was lower as compared to hypodivergent and norm divergent patients, especially at the mid-dorsum, anterior dorsum, and tongue tip regions. A weak correlation was found between mandibular arch width and tongue posture.

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“…Thus, masseter and temporalis muscles play a more crucial role in mastication, which can lead to fatigue build-up and become vulnerable to tenderness [ 52 ]. In addition, the average thickness values of the masseter muscle (13.65 ± 2.19 mm), temporalis muscle (6.66 ± 1.14 mm), MPM (14.73 ± 1.32 mm), and LPM (15.59 ± 1.40 mm) were different [ 53 , 54 , 55 ]. Specialization in fiber type composition and fiber cross-sectional area can be reflected in these intramuscular differences.…”

Section: Discussionmentioning

confidence: 99%

MRI-Based Assessment of Masticatory Muscle Changes in TMD Patients after Whiplash Injury

Lee

Auh

2021

JCM

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Objective: to investigate the change in volume and signal in the masticatory muscles and temporomandibular joint (TMJ) of patients with temporomandibular disorder (TMD) after whiplash injury, based on magnetic resonance imaging (MRI), and to correlate them with other clinical parameters. Methods: ninety patients (64 women, 26 men; mean age: 39.36 ± 15.40 years), including 45 patients with symptoms of TMD after whiplash injury (wTMD), and 45 age- and sex-matched controls with TMD due to idiopathic causes (iTMD) were included. TMD was diagnosed using the study diagnostic criteria for TMD Axis I, and MRI findings of the TMJ and masticatory muscles were investigated. To evaluate the severity of TMD pain and muscle tenderness, we used a visual analog scale (VAS), palpation index (PI), and neck PI. Results: TMD indexes, including VAS, PI, and neck PI were significantly higher in the wTMD group. In the wTMD group, muscle tenderness was highest in the masseter muscle (71.1%), and muscle tenderness in the temporalis (60.0%), lateral pterygoid muscle (LPM) (22.2%), and medial pterygoid muscle (15.6%) was significantly more frequent than that in the iTMD group (all p < 0.05). The most noticeable structural changes in the masticatory muscles occurred in the LPM with whiplash injury. Volume (57.8% vs. 17.8%) and signal changes (42.2% vs. 15.6%) of LPM were significantly more frequent in the wTMD group than in the iTMD group. The presence of signal changes in the LPM was positively correlated with the increased VAS scores only in the wTMD group (r = 0.346, p = 0.020). The prevalence of anterior disc displacement without reduction (ADDWoR) (53.3% vs. 28.9%) and disc deformity (57.8% vs. 40.0%) were significantly higher in the wTMD group (p < 0.05). The presence of headache, sleep problems, and psychological distress was significantly higher in the wTMD group than in the iTMD group. Conclusion: abnormal MRI findings and their correlations with clinical characteristics of the wTMD group were different from those of the iTMD group. The underlying pathophysiology may differ depending on the cause of TMD, raising the need for a treatment strategy accordingly.

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Correlation between mandibular morphology and masticatory muscle thickness in normal occlusion and mandibular prognathism

Cited by 9 publications

References 22 publications

Comparative analysis of myoelectric activity and mandibular movement in healthy and temporomandibular disorder subjects

Comparative analysis of myoelectric activity and mandibular movement in healthy and temporomandibular disorder subjects

Influence of Resting Tongue Posture on Mandibular Arch Width and Vertical Dimensions of Face

MRI-Based Assessment of Masticatory Muscle Changes in TMD Patients after Whiplash Injury

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