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Nickel JC, Gonzalez YM, Gallo LM, Iwasaki LR. The challenge of ecological validity in temporomandibular disorders research. J Oral Rehabil 2024. [PMID: 38661423 DOI: 10.1111/joor.13707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/29/2024] [Accepted: 04/10/2024] [Indexed: 04/26/2024]
Abstract
OBJECTIVE To review the ecological validity of outcomes from current research involving temporomandibular disorders (TMDs), with an emphasis on chronic myofascial pain and the precocious development of degenerative disease of the temporomandibular joint (TMJ). MATERIALS AND METHODS Current approaches used to study TMDs in terms of neuromechanics, masticatory muscle behaviours, and the dynamics of the autonomic nervous system (ANS) were assessed for ecological validity in this review. In particular, the available literature was scrutinized regarding the effects of sampling, environmental and psychophysiological constraints and averaging data across biological rhythms. RESULTS Validated computer-assisted numerical modelling of the neuromechanics used biological objective functions to accurately predict muscle activation patterns for jaw-loading tasks that were individual-specific. With respect to masticatory muscle behaviour, current findings refute the premise that sustained bruxing and clenching at high jaw-loading magnitudes were associated with painful TMDs such as myofascial pain. Concerning the role of the ANS in TMDs, there remains the need for personalized assessments based on biorhythms, and where the detection of dysregulated physiologic oscillators may inform interventions to relieve pain and restore normal function. CONCLUSIONS Future human research which focuses on TMD myofascial pain or the precocious development and progression of TMJ degenerative joint disease requires experimental designs with ecological validity that capture objectively measured data which meaningfully reflect circadian and ultradian states.
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Affiliation(s)
- Jeffrey C Nickel
- Department of Oral and Craniofacial Sciences, Oregon Health & Science University School of Dentistry, Portland, Oregon, USA
| | - Yoly M Gonzalez
- Department of Oral Diagnostic Sciences, University at Buffalo School of Dental Medicine, Buffalo, New York, USA
| | | | - Laura R Iwasaki
- Department of Oral and Craniofacial Sciences, Oregon Health & Science University School of Dentistry, Portland, Oregon, USA
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Bogdanov V. Type of correlation between bite force and EMG activity of the temporalis and masseter muscles during maximal and submaximal clenching. Folia Med (Plovdiv) 2023; 65:975-985. [PMID: 38351788 DOI: 10.3897/folmed.65.e107180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/24/2023] [Indexed: 02/16/2024] Open
Abstract
INTRODUCTION Maximal bite force is an important determinant of masticatory function and is essential for the estimation of dental status. Bite force is usually measured by gnathodynamometry.
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Glovsky TE, Iwasaki LR, Wu Y, Liu H, Liu Y, Sousa Melo SL, Nickel JC. Orthognathic surgery effects on temporomandibular joint compressive stresses. Orthod Craniofac Res 2023; 26 Suppl 1:142-150. [PMID: 37000157 DOI: 10.1111/ocr.12659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/18/2023] [Accepted: 03/26/2023] [Indexed: 04/01/2023]
Abstract
INTRODUCTION This study tested orthognathic surgery effects on temporomandibular joint (TMJ) compressive stresses. METHODS Pre- (T1) and post-surgery (T2) cone-beam computed tomography images were collected from consenting subjects aged ≥15 years. Anatomical data were used to measure surgical changes in anteroposterior mandibular position and occlusal plane angle (FH-OP), estimate condylar loading areas (mm2 ) and calculate T1 and T2 TMJ and jaw muscle forces (N) during canine biting via numerical modelling. Analysis of covariance tested for sex and biting angle differences in T2 - T1 TMJ compressive stresses (TMJ force/loading area, MPa). Principal component analyses identified jaw muscle forces that accounted for changes in T2 - T1 TMJ loads. Regression analyses tested the correlations between surgical changes in mandibular position, FH-OP, TMJ loads and muscle forces. RESULTS Of 148 cases screened, 28 females and 16 males provided complete records. Condylar loading areas were significantly smaller (P = .024) for females vs males (124 ± 5 vs 144 ± 7 mm2 ). T2 - T1 differences in TMJ compressive stresses varied by surgical change, biting angle and sex. Overall, the largest increases in TMJ compressive stresses post-surgery were for females with mandibular setbacks where FH-OP angle decreased. T2 - T1 changes in jaw muscle forces had moderate (ipsilateral, λ = 4.59; η2 = 0.071) to large (contralateral, λ = 1.49; η2 = 0.31) effects on TMJ loads. CONCLUSIONS T2 - T1 differences in TMJ compressive stresses during canine biting were affected by surgical changes in mandibular position and occlusal plane angle, biting angle and sex. Surgical changes altered jaw muscle forces for the same biting conditions and, thus, affected TMJ loads and compressive stresses.
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Affiliation(s)
- Taylor E Glovsky
- School of Dentistry, Oregon Health and Science University, 97201, Oregon, Portland, 2730 S Moody Ave., USA
| | - Laura R Iwasaki
- Department of Oral and Craniofacial Sciences, School of Dentistry, Oregon Health and Science University, 97201, Oregon, Portland, 2730 S Moody Ave., USA
| | - Ying Wu
- Department of Oral and Craniofacial Sciences, School of Dentistry, Oregon Health and Science University, 97201, Oregon, Portland, 2730 S Moody Ave., USA
| | - Hongzeng Liu
- Department of Oral and Craniofacial Sciences, School of Dentistry, Oregon Health and Science University, 97201, Oregon, Portland, 2730 S Moody Ave., USA
| | - Ying Liu
- Department of Biostatistics and Epidemiology, College of Public Health, East Tennessee State University, Johnson City, Tennessee, 37614, USA
| | - Saulo L Sousa Melo
- Department of Oral and Craniofacial Sciences, School of Dentistry, Oregon Health and Science University, 97201, Oregon, Portland, 2730 S Moody Ave., USA
| | - Jeffrey C Nickel
- Department of Oral and Craniofacial Sciences, School of Dentistry, Oregon Health and Science University, 97201, Oregon, Portland, 2730 S Moody Ave., USA
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She X, Sun S, Damon BJ, Hill CN, Coombs MC, Wei F, Lecholop MK, Steed MB, Bacro TH, Slate EH, Zheng N, Lee JS, Yao H. Sexual dimorphisms in three-dimensional masticatory muscle attachment morphometry regulates temporomandibular joint mechanics. J Biomech 2021; 126:110623. [PMID: 34311291 DOI: 10.1016/j.jbiomech.2021.110623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/25/2021] [Accepted: 07/05/2021] [Indexed: 10/20/2022]
Abstract
Temporomandibular joint (TMJ) disorders disproportionally affect females, with female to male prevalence varying from 3:1 to 8:1. Sexual dimorphisms in masticatory muscle attachment morphometry and association with craniofacial size, critical for understanding sex-differences in TMJ function, have not been reported. The objective of this study was to determine sex-specific differences in three-dimensional (3D) TMJ muscle attachment morphometry and craniofacial sizes and their impact on TMJ mechanics. Human cadaveric TMJ muscle attachment morphometry and craniofacial anthropometry (10Males; 11Females) were determined by previously developed 3D digitization and imaging-based methods. Sex-differences in muscle attachment morphometry and craniofacial anthropometry, and their correlation were determined, respectively using multivariate general linear and linear regression statistical models. Subject-specific musculoskeletal models of the mandible were developed to determine effects of sexual dimorphisms in mandibular size and TMJ muscle attachment morphometry on joint loading during static biting. There were significant sex-differences in craniofacial size (p = 0.024) and TMJ muscle attachment morphometry (p < 0.001). TMJ muscle attachment morphometry was significantly correlated with craniofacial size. TMJ contact forces estimated from biomechanical models were significantly, 23% on average (p < 0.001), greater for females compared to those for males when generating the same bite forces. There were significant linear correlations between TMJ contact force and both 3D mandibular length (R2 = 0.48, p < 0.001) and muscle force moment arm ratio (R2 = 0.68, p < 0.001). Sexual dimorphisms in masticatory muscle morphology and craniofacial sizes play critical roles in subject-specific TMJ biomechanics. Sex-specific differences in the TMJ mechanical environment should be further investigated concerning mechanical fatigue of TMJ discs associated with TMJ disorders.
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Affiliation(s)
- Xin She
- Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Shuchun Sun
- Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Brooke J Damon
- Department of Bioengineering, Clemson University, Clemson, SC, USA; Department of Oral Health Sciences, Medical University of South Carolina (MUSC), Charleston, SC, USA
| | - Cherice N Hill
- Department of Bioengineering, Clemson University, Clemson, SC, USA; Department of Oral Health Sciences, Medical University of South Carolina (MUSC), Charleston, SC, USA
| | - Matthew C Coombs
- Department of Bioengineering, Clemson University, Clemson, SC, USA; Department of Oral Health Sciences, Medical University of South Carolina (MUSC), Charleston, SC, USA
| | - Feng Wei
- Department of Bioengineering, Clemson University, Clemson, SC, USA
| | | | - Martin B Steed
- Department of Oral and Maxillofacial Surgery, MUSC, Charleston, SC, USA
| | - Thierry H Bacro
- Center for Anatomical Studies and Education, MUSC, Charleston, SC, USA
| | - Elizabeth H Slate
- Department of Statistics, Florida State University, Tallahassee, FL, USA
| | - Naiquan Zheng
- Department of Mechanical Engineering and Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, NC, USA
| | | | - Hai Yao
- Department of Bioengineering, Clemson University, Clemson, SC, USA; Department of Oral Health Sciences, Medical University of South Carolina (MUSC), Charleston, SC, USA.
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Marková M, Gallo LM. The influence of the human TMJ eminence inclination on predicted masticatory muscle forces. Hum Mov Sci 2016; 49:132-40. [PMID: 27376178 DOI: 10.1016/j.humov.2016.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 05/09/2016] [Accepted: 06/23/2016] [Indexed: 12/19/2022]
Abstract
Aim of this paper was to investigate the change in masticatory muscle forces and temporomandibular joint (TMJ) reaction forces simulated by inverse dynamics when thesteepness of the anterior fossa slope was varied. We used the model by de Zee et al. (2007) created in AnyBody™. The model was equipped with 24musculotendon actuators. Mandibular movement was governed by thetrajectory of theincisal point. The TMJ was modelled as a planar constraint canted 5°medially and thecaudal inclination relative to the occlusal plane was varied from 10° to 70°. Our models showed that for the two simulated movements (empty chewing and unilateral clenching) the joint reaction forces were smallest for the eminence inclination of 30° and 40° and highest for 70°. The muscle forces were relatively insensitive to change of the eminence inclination for the angles between 20° and 50°. This did not hold for the pterygoid muscle, for which the muscle forces increased continually with increasing fossa inclination. For empty chewing the muscle force reached smaller values than for clenching. During clenching, the muscle forces changed by up to 200N.
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Affiliation(s)
- Michala Marková
- Clinic of Masticatory Disorders, Removable Prosthodontics, Geriatric and Special Care Dentistry, University of Zürich, Plattenstrasse 11, 8032 Zürich, Switzerland; Laboratory of Biomechanics, Department of Mechanics, Biomechanics and Mechatronics, Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 16607 Prague 6, Czech Republic.
| | - Luigi M Gallo
- Clinic of Masticatory Disorders, Removable Prosthodontics, Geriatric and Special Care Dentistry, University of Zürich, Plattenstrasse 11, 8032 Zürich, Switzerland.
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Reynolds AK, Nickel JC, Liu Y, Leeper DK, Riffel KM, Liu H, Iwasaki LR. Sex differences in jaw muscle duty factors during exercise in two environments: A pilot study. J Electromyogr Kinesiol 2016; 30:15-22. [PMID: 27236045 DOI: 10.1016/j.jelekin.2016.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 04/28/2016] [Accepted: 05/13/2016] [Indexed: 11/17/2022] Open
Abstract
It is unknown if females and males use jaw muscles similarly during exercise. This pilot study assessed jaw elevator muscle duty factors (DFs=time of muscle activity/total recording time) at repeated sessions to test if DFs are reliable and different between sexes during exercises in two environments. Ten female and seven male subjects recruited from university soccer teams provided informed consent. Surface electromyography was recorded from masseter and temporalis muscles during biting and leg-extension laboratory exercises. Average activities to produce 20N bite-forces for each muscle and subject determined thresholds (5-80%·T20N) for subject-specific DF calculations during exercises performed in laboratory and natural environments. Subjects self-recorded via portable electromyography equipment during in-field leg-extension and weight-lifting exercises. Effects of variables on DFs were assessed via ANOVA (α=0.05) and simple effects testing (Bonferroni-adjusted p⩽0.012). All subjects used jaw muscles during exercises in both environments. DFs between laboratory sessions were reliable (R=0.84). During laboratory exercises, male temporalis DFs were significantly higher than female DFs from both muscles (p⩽0.001). During in-field exercises females had higher DFs during weight-lifting while males had higher DFs during leg-extensions. In-field sex differences were significant at most thresholds and showed larger effect sizes for leg-extension compared to weight-lifting exercises.
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Affiliation(s)
| | - Jeffrey C Nickel
- University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, United States
| | - Ying Liu
- East Tennessee State University, College of Public Health, Johnson City, TN, United States
| | - Danielle K Leeper
- Texas A & M University, Baylor College of Dentistry, Dallas, TX, United States
| | - Kelsey M Riffel
- University of Nebraska Medical Center, College of Dentistry, Lincoln, NE, United States
| | - Hongzeng Liu
- University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, United States
| | - Laura R Iwasaki
- University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, United States.
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Turcio KHL, Zuim PRJ, Guiotti AM, Dos Santos DM, Goiato MC, Brandini DA. Does the habitual mastication side impact jaw muscle activity? Arch Oral Biol 2016; 67:34-8. [PMID: 27019139 DOI: 10.1016/j.archoralbio.2016.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 03/08/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To compare electrical activity in the anterior temporal and masseter muscles on the habitual (HMS) and non-habitual mastication side (NHMS), during mastication and in the mandibular postural position. In addition, the increase in electrical activity during mastication was assessed for the HMS and NHMS, analysing both working (WSM) and non-working side during mastication (NWSM). METHODS A total of 28 healthy women (18-32 years) participated in the study. They were submitted to Kazazoglu's test to identify the HMS. Bioresearch 'Bio EMG' software and bipolar surface electrodes were used in the exams. The exams were conducted in the postural position and during the unilateral mastication of raisins, on both the HMS and NHMS. The working and non-working side on HMS and NHMS were assessed separately. The obtained data were then statistically analysed with SPSS 20.0, using the Paired Samples Test at a significance level of 95%. RESULTS The differences in the average EMG values between HMS and NHMS were not statistically significant in the postural position (Temporal p=0.2; Masseter p=0.4) or during mastication (Temporal WSM p=0.8; Temporal NWSM p=0.8; Masseter WSM p=0.6; Masseter NWSM p=0.2). Differences in the increase in electrical activity between the masseter and temporal muscles occurred on the working side, on the HMS and NHMS (p=0.0), but not on the non-working side: HMS (p=0.9) and NHMS (p=0.3). The increase in electrical activity was about 35% higher in the masseter than in the temporal muscle. CONCLUSIONS Mastication side preference does not significantly impact electrical activity of the anterior temporal and masseter muscles during mastication or in postural position.
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Affiliation(s)
- Karina Helga Leal Turcio
- Department of Dental Materials and Prosthodontics, Araçatuba Dental School, UNESP-Univ Estadual Paulista, São Paulo, Brazil.
| | - Paulo Renato Junqueira Zuim
- Department of Dental Materials and Prosthodontics, Araçatuba Dental School, UNESP-Univ Estadual Paulista, São Paulo, Brazil
| | - Aimée Maria Guiotti
- Department of Dental Materials and Prosthodontics, Araçatuba Dental School, UNESP-Univ Estadual Paulista, São Paulo, Brazil
| | - Daniela Micheline Dos Santos
- Department of Dental Materials and Prosthodontics, Araçatuba Dental School, UNESP-Univ Estadual Paulista, São Paulo, Brazil
| | - Marcelo Coelho Goiato
- Department of Dental Materials and Prosthodontics, Araçatuba Dental School, UNESP-Univ Estadual Paulista, São Paulo, Brazil
| | - Daniela Atili Brandini
- Department of Integrated Clinic, Araçatuba Dental School, UNESP-Univ Estadual Paulista, São Paulo, Brazil
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Iwasaki LR, Liu H, Gonzalez YM, Marx DB, Nickel JC. Modeling of muscle forces in humans with and without temporomandibular joint disorders. Orthod Craniofac Res 2015; 18 Suppl 1:170-9. [PMID: 25865546 DOI: 10.1111/ocr.12075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces. SETTING AND SAMPLE POPULATION School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in four groups based on the presence/absence (±) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD). MATERIAL AND METHODS Validated numerical models employed an organizational objective and subjects' anatomy to calculate masticatory muscle forces during static biting. anova and Holm's step-down procedure post hoc tests assessed group differences. Theoretical geometries, representing the range of subjects' muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect size (Cohen's d) and anova/post hoc tests assessed group differences in key muscle orientations. RESULTS +P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (p<0.01) for bite forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified, and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly directed for temporalis muscles (all Cohen's d≥0.8). CONCLUSION Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations.
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Affiliation(s)
- L R Iwasaki
- Departments of Orthodontics & Dentofacial Orthopedics and Oral & Craniofacial Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
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Khawaja SN, Iwasaki LR, Dunford R, Nickel JC, McCall W, Crow HC, Gonzalez Y. Association of Masseter Muscle Activities during Awake and Sleep Periods with Self-Reported Anxiety, Depression, and Somatic Symptoms. ACTA ACUST UNITED AC 2015; 2. [PMID: 26709387 DOI: 10.15406/jdhodt.2015.02.00039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AIM AND BACKGROUND The objective of this study was to determine if duty factors (DF) of low-magnitude MMA during awake and sleep periods were associated with self-reports of anxiety, depression, and somatic symptoms, and if so, whether or not any associations were modified by gender or the presence of pain. Limited information is currently available in the literature regarding the association of low-magnitude masseter muscle activities (MMA) in habitual environmental settings and the presence of psychological symptoms. MATERIALS AND METHODS Sixty-eight consenting participants were classified using the Diagnostic Criteria for Temporomandibular Disorders examination and validated self-reporting psychological symptom evaluation questionnaires. Each subject also had masseter electromyography recordings during standardized biting tasks in 2 laboratory sessions to calibrate the in-field MMA collected during 3 awake and 3 sleep periods. RESULTS During awake periods, subjects with self-reported depression and somatic symptoms had statistically high odds of having higher DF of low-magnitude MMA (defined by ≥ 75th percentile of sample). The association between high DF of low-magnitude MMA and self-reported depression symptoms was significantly augmented among male participants, whereas, the association between high DF of low-magnitude MMA and self-reported somatic symptoms was significantly increased among female participants without pain. CONCLUSION These pilot data support associations of low-magnitude masseter muscle activities with self-reported depression and somatic symptoms during awake periods.
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Affiliation(s)
| | - Laura R Iwasaki
- Departments of Orthodontics & Dentofacial Orthopedics and Oral & Craniofacial Sciences, University of Missouri-Kansas City, USA
| | | | - Jeffrey C Nickel
- Departments of Orthodontics & Dentofacial Orthopedics and Oral & Craniofacial Sciences, University of Missouri-Kansas City, USA
| | | | - Heidi C Crow
- Oral Diagnostic Sciences, University at Buffalo, USA
| | - Yoly Gonzalez
- Oral Diagnostic Sciences, University at Buffalo, USA
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Santana-Mora U, Martínez-Ínsua A, Santana-Penín U, del Palomar AP, Banzo JC, Mora MJ. Muscular activity during isometric incisal biting. J Biomech 2014; 47:3891-7. [DOI: 10.1016/j.jbiomech.2014.09.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 08/29/2014] [Accepted: 09/06/2014] [Indexed: 11/30/2022]
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Truong Quang Dang K, Le Minh H, Nguyen Thanh H, Vo Van T. Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss. Biomed Eng Online 2012; 11:55. [PMID: 22913755 PMCID: PMC3494581 DOI: 10.1186/1475-925x-11-55] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/16/2012] [Indexed: 12/02/2022] Open
Abstract
Background This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. Methods In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles – masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles – were involved. Integrated EMG (iEMG) and Higuchi fractal dimension (HFD) were used to analyze the EMG signals. Results The results showed that (1) Imbalance in the jaw causes loss of arm strength contra-laterally; (2) The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased). In addition, the tendency of Higuchi fractal dimension decreased for all muscles. Conclusions This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength.
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Affiliation(s)
- Khoa Truong Quang Dang
- Biomedical Engineering Department, International University of Vietnam National Universities in Ho Chi Minh City, Quarter 6, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, Vietnam.
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Nickel JC, Gonzalez YM, McCall WD, Ohrbach R, Marx DB, Liu H, Iwasaki LR. Muscle organization in individuals with and without pain and joint dysfunction. J Dent Res 2012; 91:568-73. [PMID: 22522774 DOI: 10.1177/0022034512445909] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Central nervous system organization of masticatory muscles determines the magnitude of joint and muscle forces. Validated computer-assisted models of neuromuscular organization during biting were used to determine organization in individuals with and without temporomandibular disorders (TMD). Ninety-one individuals (47 women, 44 men) were assigned to one of four diagnostic groups based on the presence (+) or absence (-) of pain (P) and bilateral temporomandibular joint disc displacement (DD). Electromyography and bite-forces were measured during right and left incisor and molar biting. Two three-dimensional models employing neuromuscular objectives of minimization of joint loads (MJL) or muscle effort (MME) simulated biting tasks. Evaluations of diagnostic group and gender effects on choice of best-fit model were by analysis of variance (ANOVA) and Tukey-Kramer post hoc tests, evaluations of right-left symmetry were by Chi-square and Fisher's exact statistics, and evaluations of model accuracy were by within-subject linear regressions. MME was the best-fit during left molar biting in +DD individuals and incisor biting in men (all p < 0.03). Incisor biting symmetry in muscle organization was significantly higher (p < 0.03) in healthy individuals compared with those with TMD. Within-subject regressions showed that best-fit model errors were similar among groups: 8 to 15% (0.68 ≤ R(2) ≤ 0.74). These computer-assisted models predicted muscle organization during static biting in humans with and without TMDs.
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Affiliation(s)
- J C Nickel
- University of Missouri-Kansas City, School of Dentistry, Department of Orthodontics & Dentofacial Orthopedics, Kansas City, MO 64108, USA
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Shiraishi T, Chikui T, Inadomi D, Kagawa T, Yoshiura K, Yuasa K. Evaluation of diffusion parameters and T2 values of the masseter muscle during jaw opening, clenching, and rest. Acta Radiol 2012; 53:81-6. [PMID: 22156008 DOI: 10.1258/ar.2011.110136] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI) can be used to evaluate changes that accompany skeletal muscle contraction. PURPOSE To investigate whether jaw opening or closure affect the diffusion parameters of the masseter muscles (MMs). MATERIAL AND METHODS Eleven healthy volunteers were evaluated. Diffusion-tensor images were acquired to obtain the primary (λ(1)), secondary (λ(2)), and tertiary eigenvalues (λ(3)). We estimated these parameters at three different locations: at the level of the mandibular notch for the superior site, the level of the mandibular foramen for the middle site, and the root apex of the mandibular molars for the inferior site. RESULTS Both λ(2) and λ(3) during jaw opening were significantly lower than that at rest at the superior (P = 0.006, P < 0.0001, respectively) and middle site (P = 0.004, P = 0.0001, respectively); however, the change in λ(1) was not significant. At the lower site, no parameter was significantly different at rest and during jaw opening. There was no significant difference in T2 between at rest (40.3 ± 4.4 ms) and during jaw opening (39.2 ± 2.7 ms; P = 0.12). The changes induced by jaw closure were marked at the inferior site. In the middle and inferior sites, the three eigenvalues were increased by jaw closure, and the changes in λ(1) (P = 0.0145, P = 0.0107, respectively) and λ(2) (P = 0.0003, P = 0.0001) were significant (especially λ(2)). CONCLUSION The eigenvalues for diffusion of the MM were sensitive to jaw position. The recruitment of muscle fibers, specific to jaw position, reflects the differences in changes in muscle diffusion parameters.
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Affiliation(s)
- Tomoko Shiraishi
- Section of Image Diagnosis, Department of Diagnostics and General Care, Fukuoka Dental College, Fukuoka
| | - Toru Chikui
- Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka
| | - Daisuke Inadomi
- Department of Radiology, Fukuoka Dental College Medical and Dental Hospital, Fukuoka, Japan
| | - Toyohiro Kagawa
- Section of Image Diagnosis, Department of Diagnostics and General Care, Fukuoka Dental College, Fukuoka
| | - Kazunori Yoshiura
- Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Fukuoka
| | - Kenji Yuasa
- Section of Image Diagnosis, Department of Diagnostics and General Care, Fukuoka Dental College, Fukuoka
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Gonzalez Y, Iwasaki LR, McCall WD, Ohrbach R, Lozier E, Nickel JC. Reliability of electromyographic activity vs. bite-force from human masticatory muscles. Eur J Oral Sci 2011; 119:219-24. [PMID: 21564316 DOI: 10.1111/j.1600-0722.2011.00823.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The reproducibility of electromyographic (EMG) activity in relation to static bite-force from masticatory muscles for a given biting situation is largely unknown. Our aim was to evaluate the reliability of EMG activity in relation to static bite-force in humans. Eighty-four subjects produced five unilateral static bites of different forces at different biting positions on molars and incisors, at two separate sessions, and the surface EMG activities were recorded from temporalis, masseter, and suprahyoid muscles bilaterally. Intraclass correlation coefficients (ICCs) were determined, and an ICC of ≥ 0.60 indicated good reliability of these slopes. The ICCs for jaw-closing muscles during molar biting were: temporalis muscles, ipsilateral 0.58-0.93 and contralateral 0.88-0.91; and masseter muscles, ipsilateral 0.75-0.86 and contralateral 0.69-0.88. The ICCs for jaw-closing muscles during incisor biting were: temporalis muscles, ipsilateral 0.56-0.81 and contralateral 0.34-0.86; and masseter muscles, ipsilateral 0.65-0.78 and contralateral 0.59-0.80. For the suprahyoid muscles the 95% CIs were mostly wide and most included zero. The slopes of the EMG activity vs. bite-force for a given biting situation were reliable for temporalis and masseter muscles. These results support the use of these outcome measurements for the estimation and validation of mechanical models of the masticatory system.
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Affiliation(s)
- Y Gonzalez
- Department of Oral Diagnostic Sciences, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA.
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16
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Shiraishi T, Chikui T, Yoshiura K, Yuasa K. Evaluation of T2 values and apparent diffusion coefficient of the masseter muscle by clenching. Dentomaxillofac Radiol 2011; 40:35-41. [PMID: 21159913 DOI: 10.1259/dmfr/15607259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The aim of this study was to evaluate the changes in T2 values and apparent diffusion coefficient (ADC) in the masseter muscle by clenching in healthy volunteers. METHODS 37 volunteers were enrolled in the study. We measured bite force using pressure-sensitive paper and a T2 map. The ADC map was obtained at rest, during clenching, immediately after and 5 min after clenching. The spin-echo sequence was used to calculate T2, and single-shot spin-echo echo planar imaging was used to calculate the ADC. The motion-probing gradients (MPGs) were applied separately along the posterior-to-anterior (PA), right-to-left (RL) and superior-to-inferior (SI) directions, with b values of 0, 300 and 600 s mm(-2) in each direction. ADC-PA, ADC-RL, and ADC-SI values were obtained, and we calculated the ADC-iso for the mean diffusivity. RESULTS There were no significant differences between the stronger and weaker sides of bite force before, during or 5 min after clenching for T2 and ADC. The bite force had little effect on these parameters; thus, we used the average of the two sides for the following analyses. Time course analysis of ADC-iso, ADC-PA, ADC-RL and ADC-SI demonstrated a marked increase after clenching and a rapid decrease immediately after clenching, although they did not completely return to the initial values; however, the change in ADC-RL was significantly greater than those in ADC-PA or ADC-SI (P<0.001 each). The changes in T2 were similar to those of ADC, although not as marked. CONCLUSIONS ADC (especially ADC-RL) was altered by contraction of the masseter muscle.
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Affiliation(s)
- T Shiraishi
- Section of Image Diagnosis, Department of Diagnostics and General Care, Fukuoka Dental College, Tamura 2-15-1, Sawara-ku, Fukuoka 814-0193, Japan.
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Influence of bite force on jaw muscle activity ratios in subject-controlled unilateral isometric biting. J Electromyogr Kinesiol 2010; 20:961-6. [DOI: 10.1016/j.jelekin.2010.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 03/03/2010] [Accepted: 03/24/2010] [Indexed: 11/24/2022] Open
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Influence of changing occlusal support on jaw-closing muscle electromyographic activity in healthy men and women. Acta Odontol Scand 2009; 67:187-92. [PMID: 19291503 DOI: 10.1080/00016350902794800] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To test whether changes in occlusal support differentially modulate masseter and anterior temporalis muscle electromyographic (EMG) activity during controlled maximal voluntary clenching. MATERIAL AND METHODS Forty-seven healthy subjects (32 M and 15 F, 22.9+/-1.3 years) were recruited. Cotton-rolls were used to modify the occlusal contact relations and were positioned on the right, left, or both sides, and either in the molar or premolar regions, i.e. six different occlusal combinations. Surface EMG activity was recorded bilaterally from the masseter and anterior temporalis area and normalized with respect to maximal voluntary clenching in the intercuspal position. Analysis of variance and the paired t-test were used to test the data. RESULTS Normalized EMG activity was influenced by changes in cotton-roll modified occlusal support, and there were differences between muscles (p<0.001). In general, EMG activity decreased in both muscles when occlusal support was moved from the molar to the premolar region. When occlusal support was moved from bilateral to unilateral contacts, EMG activity in the balancing-side anterior temporalis muscle and in bilateral masseter muscles decreased. Unilateral clenching on the molars, but not on the premolars, was associated with lower EMG activity in the balancing-side masseter and always associated with lower EMG activity in the balancing-side anterior temporalis compared to the working side (p<0.05). CONCLUSIONS Masseter and anterior temporalis muscles respond differently to changes in occlusal support, which may have implications for stability of the mandible during intense clenching.
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