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BACKGROUND: The present study is to evaluate the clinical characteristics of patients with temporomandibular disorders (TMD). METHODS: A total of 3362 TMD patients were included. Each participant had complete medical records according to the diagnostic criteria for temporomandibular disorders (DC/TMD). The clinical characteristics including symptoms and signs in relation to age and gender were analyzed. RESULTS: The mean age of the patients seeking care was 29.89 ± 13.73Y, and 68.6% of patients were aged 16-35 years. The female-to-male ratio of patients was 2.2: 1, and the average age of males was significantly lower than that of females. The prevalence of clicking symptoms decreased with age, while the prevalence of pain symptoms and limitations in jaw movement increased with age. Females were more likely to have limitations in jaw movement than males. Among the patients with pain, the average visual analogue scale (VAS) was 2.96 ± 1.23. The average VAS score of acute TMD patients (≤ 3 months) was significantly higher than that of chronic TMD patients (> 3 months). CONCLUSIONS: The majority of TMD patients seeking care were young people. The number and average age of female patients was higher than the males. Female patients were more likely to have limitations in jaw movement than males.
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Transtornos da Articulação Temporomandibular , Humanos , Masculino , Feminino , Transtornos da Articulação Temporomandibular/epidemiologia , Adulto , Estudos Retrospectivos , Adolescente , Fatores Sexuais , Fatores Etários , Adulto Jovem , Dor Facial , Pessoa de Meia-Idade , Medição da Dor , PrevalênciaRESUMO
BACKGROUND: Limiting postoperative edema, pain, trismus, and infection is crucial for smooth healing. This prospective, controlled clinical trial investigated and compared the effectiveness of dexamethasone and hyaluronidase in relieving these complications. METHODS: In groups Ia and IIa, 8 mg of dexamethasone and 150 IU of hyaluronidase were administered following the removal of impacted teeth, respectively. The contralateral sides (groups Ib and IIb) were determined as control groups. Edema, pain, trismus, and infection were clinically evaluated on the 1st, 2nd, 3rd, and 7th postoperative days. RESULTS: 60 patients were enrolled in the study. Hyaluronidase provided significantly more edema relief than dexamethasone on the 1st, 2nd, 3rd, and 7th postoperative days (P = 0.031, 0.002, 0.000, and 0.009, respectively). No statistical difference was found between dexamethasone and hyaluronidase in VAS and rescue analgesic intake amount values for all time points. Hyaluronidase was more effective in reducing trismus than dexamethasone on the 2nd and 3rd postoperative days (P = 0.029, 0.024, respectively). Neither of the agents significantly increased the postoperative infection rate. CONCLUSIONS: Hyaluronidase can be selected when postoperative excessive edema and trismus are anticipated. Dexamethasone may be a cost-effective option if postoperative pain control is merely targeted. TRIAL REGISTRATION: This trial was registered in the Clinical Trials Protocol Registration and Results System (ClinicalTrials.gov identifier number: NCT05466604) on 20/07/2022.
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Dexametasona , Edema , Hialuronoglucosaminidase , Dente Serotino , Dor Pós-Operatória , Dente Impactado , Trismo , Humanos , Dexametasona/uso terapêutico , Hialuronoglucosaminidase/uso terapêutico , Trismo/prevenção & controle , Edema/prevenção & controle , Dor Pós-Operatória/prevenção & controle , Dor Pós-Operatória/tratamento farmacológico , Dente Serotino/cirurgia , Dente Impactado/cirurgia , Masculino , Feminino , Estudos Prospectivos , Adulto , Adulto Jovem , Extração Dentária/efeitos adversos , Anti-Inflamatórios/uso terapêutico , Complicações Pós-Operatórias/prevenção & controle , Medição da Dor , Adolescente , Infecção da Ferida Cirúrgica/prevenção & controleRESUMO
Objective: This study aimed to investigate the added effect of jaw clenching on the efficacy of lumbar stabilization exercises to manage chronic non-specific low back pain. Methods: This randomized controlled trial was conducted at the Sindh Institute of Physical Medicine and Rehabilitation (SIPM&R) Karachi from April 2021 to April 2023. Eighty patients with chronic non-specific low back pain participated in this study. Forty patients each were randomly allocated to the lumbar stability exercise (LSE) group' and the lumbar stability exercise with teeth clenching (LSETC) group. Patients in both groups performed respective exercises twice weekly for 12 weeks. The Numeric Pain Rating Scale (NPRS), Roland Morris Disability Questionnaire (RMDQ), and Pressure Biofeedback Unit (PBU) were used to assess pain, disability, and muscle endurance respectively. Data were collected at the baseline, after six weeks and 12 weeks of intervention. A p-value of <0.05 was considered statistically significant. Results: Both groups showed statistically significant improvements in pain, disability, and muscle endurance. Upon further stratification, participants aged 20-30 years in the LSETC group showed significantly higher scores than the LSE group for NPRS, RMDQ, and PBU after 12 weeks. Overall, the LSETC group showed relatively higher improvement in mean scores for NPRS, RMDQ, and PBU than the LSE group. Conclusion: Lumbar stabilization exercises with and without jaw movement are effective for the treatment of chronic non-specific low back pain. The addition of teeth clenching enhanced the effectiveness of lumbar stability exercises, especially in young adults. Trial Registration: Clinicaltrials.gov (NCT04801212), Prospectively registered on March 16, 2021.
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Technology has revolutionized the way dentists are able to treat their patients. These technological advances have paved the way for the creation of virtual patient models utilizing these 3-dimensional intra-oral patient models, cone bean computer tomography (CBCT) radiograph scans, extraoral 3-dimensional scans, and jaw motion tracings to create a patient-specific model. These models are advantageous in planning surgical treatments by providing 3-dimensional views of vital anatomical structures to accurately identify the location, size, and shape of a structure or defect in order to plan accordingly. Virtual augmentation of either hard tissue (bone) and/or soft tissue (i.e., gingiva) can also be accomplished.Technology has allowed the capture of the dynamic motions of the jaw and combined them with the virtual patient to develop permanent restorations in harmony with the patient's orofacial complex. With the introduction of new technology in the realm of digital dentistry, patient care is being brought to a new and higher level. This creates a level of more optimal care that a dentist can deliver to patients.
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Tomografia Computadorizada de Feixe Cônico , Imageamento Tridimensional , Humanos , Imageamento Tridimensional/métodos , Tomografia Computadorizada de Feixe Cônico/métodos , Invenções , OdontologiaRESUMO
BACKGROUND: The assessment of masticatory performance (MP) is conducted in hospitals, but is difficult to perform in nursing facilities that lack specialists in dysphagia. To select the appropriate food textures in nursing practice, a simple method of evaluating the MP should be developed. OBJECTIVE: The purpose of this study was to investigate motion parameters that influence MP by motion capture analysis of maxillofacial movement on chewing gummy jelly in healthy adults. METHODS: The subjects were 50 healthy adults. The state of chewing gummy jelly was photographed using a high-speed camera. Simultaneously, we evaluated the amount of glucose extracted (AGE) obtained with gummy jelly as a reference value for MP. The subjects were divided into two groups: normal and low masticatory groups (NG and LG, respectively) based on the AGE. The cycle of mastication was classified into three phases: closing phase (CP), transition phase (TP) and opening phase (OP) through motion capture analysis of the video photographed. Parameters of jaw movement and their associations with the AGE were examined. RESULTS: The transition phase rate (TR) and opening phase rate (OR) were correlated with the AGE. Furthermore, the TR in the NG was significantly higher than in the LG, whereas the OR was significantly lower than in the LG. The age, TR and opening velocity were significant independent variables. CONCLUSION: Motion capture technology facilitated the analysis of jaw movement. The results suggested that MP can be evaluated by analysing the TP and OP rates.
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Mastigação , Captura de Movimento , Adulto , Humanos , Alimentos , Movimento , Goma de MascarRESUMO
We proposed a novel jaw movement tracking method that can measure in six degrees of freedom. The magnetic field generated by a permanent magnet paired with a small, low-power-consumption Hall effect magnetic sensor is used to estimate the relative distance between two objects-in this instance, the lower and upper jaws. By installing a microelectromechanical system (MEMS) orientation sensor in the device, we developed a mouthpiece-type sensing device that can measure voluntary mandibular movements in three-dimensional orientation and position. An evaluation of individuals wearing this device demonstrated its ability to measure mandibular movement with an accuracy of approximately 3 mm. Using the movement recording feature with six degrees of freedom also enabled the evaluation of an individual's jaw movements over time in three dimensions. In this method, all sensors are built onto the mouthpiece and the sensing is completed in the oral cavity. It does not require the fixation of a large-scale device to the head or of a jig to the teeth, unlike existing mandibular movement tracking devices. These novel features are expected to increase the accessibility of routine measurements of natural jaw movement, unrestricted by an individual's physiological movement and posture.
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Arcada Osseodentária , Movimento , Humanos , Movimento/fisiologia , Arcada Osseodentária/fisiologia , Magnetismo , Mandíbula/fisiologia , Fenômenos MagnéticosRESUMO
OBJECTIVES: To investigate whether masticatory movements in older patients with eating difficulties were associated with oral motor function, physical function, and appropriate food textures. BACKGROUND: There are few reports on the association between masticatory movements and food textures in older patients with eating difficulties. MATERIALS AND METHODS: This cross-sectional study involved outpatients at a clinic that specialised in eating and swallowing rehabilitation. Masticatory movements were evaluated as normal or abnormal masticatory path patterns. Oral and physical functions were assessed in terms of oral and physical status, muscle strength and motor skills. The appropriate food texture was determined based on fibreoptic endoscopic evaluation of swallowing and a video fluoroscopic swallowing study. The associations between food texture and masticatory organ, muscle strength and motor skills were analysed. RESULTS: A total of 126 outpatients (75 men and 51 women; mean age, 78.2 years; SD, 9.6 years) were included in the analysis. 68 participants (54.0%) showed abnormal masticatory movements. Masticatory movement was associated with masticatory performance (odds ratio [OR] = 0.99, 95% confidence interval [CI] = 0.98-0.99), oral diadochokinesis (OR = 0.55, CI = 0.35-0.86) and stepping test (OR = 0.92, CI = 0.86-0.97). Masticatory movement (OR = 2.94, CI = 1.23-7.01) and the number of natural teeth (OR = 0.94, CI = 0.89-0.99) were associated with normal food. CONCLUSION: Masticatory movements in older patients with eating difficulties may be associated with appropriate food textures whilst being influenced by individual differences in systemic motor control. Masticatory movements may be as important as teeth to enjoy eating.
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Mastigação , Dente , Idoso , Estudos Transversais , Deglutição/fisiologia , Feminino , Alimentos , Humanos , Masculino , Mastigação/fisiologiaRESUMO
PURPOSE: To establish a direct digital method for determining and recording edentulous maxillomandibular relationship using a custom-made jaw movement tracking system and evaluate its accuracy. MATERIALS AND METHODS: A novel jaw tracking system was used to record the trajectory of habitual opening-closing jaw movement, and mandibular rest position (MRP) in 10 edentulous patients. 3D surface scanning was performed on the conventional maxillomandibular impressions and facial structures of patients in MRP. The multisource data were registered using a custom-made recording tool. A plane parallel to the ala-tragus and horizontal lines was constructed 2 mm above the MRP, and its vertical position was used to determine the vertical relationship. The intersections of the trajectory passing through the plane were located, and their density distributions were analyzed. The coordinates of highest density, which presented the highest repeatability of jaw movement, were used to construct the digital maxillomandibular relationship (test group). The maxillomandibular relationship of the new complete dentures with artificial teeth in the intercuspal position was defined as the control group. The displacements of the anterior reference point and 3D deviations of the entire mandibular arch were measured and compared between the test and control groups using a Wilcoxon signed-ranks test and a one-sample t-test, respectively. RESULTS: With reference to the centric relationship position, the maximum displacements of the anterior reference points were in the horizontal anteroposterior direction for both groups, and there were no significant differences. Compared to the control group, the 3D deviations of the entire mandibular arch in the test group were significant (95% confidence interval: 0.76 mm to 1.35 mm, p < 0.001). CONCLUSIONS: By analyzing the individual trajectory features obtained by the in-house developed jaw tracking system, a digital method for determining and recording edentulous maxillomandibular relationships was established; however, the accuracy needs to be further improved.
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Arcada Edêntula , Boca Edêntula , Humanos , Prótese Total , Dimensão Vertical , Movimento , Registro da Relação MaxilomandibularRESUMO
Determining ingestive behaviors of dairy cows is critical to evaluate their productivity and health status. The objectives of this research were to (1) develop the relationship between forage species/heights and sound characteristics of three different ingestive behaviors (bites, chews, and chew-bites); (2) comparatively evaluate three deep learning models and optimization strategies for classifying the three behaviors; and (3) examine the ability of deep learning modeling for classifying the three ingestive behaviors under various forage characteristics. The results show that the amplitude and duration of the bite, chew, and chew-bite sounds were mostly larger for tall forages (tall fescue and alfalfa) compared to their counterparts. The long short-term memory network using a filtered dataset with balanced duration and imbalanced audio files offered better performance than its counterparts. The best classification performance was over 0.93, and the best and poorest performance difference was 0.4-0.5 under different forage species and heights. In conclusion, the deep learning technique could classify the dairy cow ingestive behaviors but was unable to differentiate between them under some forage characteristics using acoustic signals. Thus, while the developed tool is useful to support precision dairy cow management, it requires further improvement.
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Dieta , Lactação , Ração Animal/análise , Animais , Bovinos , Comportamento Alimentar , Feminino , Mastigação , Medicago sativaRESUMO
The objective of this study was to verify whether loss of posterior occlusal support induced displacement of the mandibular condyles from a physiological point of view. Stabilization-type splints were fabricated for 12 healthy dentulous individuals. Each splint was designed to cover the bilateral maxillary teeth up to the second molars. To reproduce loss of posterior occlusal support, the extent of the splint was reduced one tooth at a time, bilaterally, starting from the back and moving forward sequentially. Tapping movement and lateral excursions were performed with each splint and a jaw movement tracking device with 6-degrees of freedom used to observe condylar displacement. Evaluation of 3-dimensional (3-D) displacement of the kinematic axis of the condyle during experimental jaw movement was performed under each occlusal condition with occlusal contact on all teeth, including the maxillary second molars. The habitual closing position was used as the reference. An increase was observed in 3-D displacement of the kinematic axis at the terminal point of the tapping movement with loss of occlusal support, and significant differences were observed in both condyles. An increase was also observed in 3-D displacement of the kinematic axis on the working side during lateral excursion with loss of occlusal support, and a statistically significant difference was observed in the left condyle. A small increase was observed in 3-D displacement of the kinematic axis on the non-working side during lateral excursion with loss of occlusal support. The results of this study suggest that loss of posterior occlusal support induces displacement of the mandibular condyles, suggesting that occlusal support in the molar region is an important factor in stabilization of the condylar position.
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Côndilo Mandibular , Dente , Humanos , Dente Molar , Movimento , ContençõesRESUMO
Observation of ingestive and rumination behaviors of dairy cows may assist in detecting diseases, controlling reproductive status, and estimating intake. However, direct observation of cows on pasture is time consuming and can be difficult to realize. Consequently, different systems have been developed to automatically record behavioral characteristics; among them is the RumiWatch System (RWS; Itin and Hoch GmbH, Liestal, Switzerland). Until now, the RWS has not been thoroughly validated under grazing conditions. The aim of the current study was to validate the RWS, against direct observation, in measuring ingestive and rumination behaviors of dairy cows during grazing and supplementation in the barn. A further objective was to examine whether it is possible to refine the algorithm used by the evaluation software RumiWatch Converter 0.7.3.2 to improve the accuracy of the RWS. The data were collected from an experiment carried out with 18 lactating Holstein cows in a crossover block design including 3 treatments and 3 measuring periods. All cows grazed night and day, 19 h/d, and were either unsupplemented or supplemented, with chopped whole-plant corn silage, or chopped whole-plant corn silage mixed with a protein concentrate. During the measuring periods, cows were equipped with the RumiWatch Halter, and their ingestive and rumination behaviors were recorded concurrently by the RumiWatch Halter and by direct observation (690 × 10 min). Comparison of concurrently measured data shows that the RWS detected jaw movements reliably, but classification errors occurred. A low relative prediction error of ≤0.10 for the number of rumination boluses, rumination chews, and total eating chews was found. A high relative prediction error of >0.10 was found for the number of prehension bites and time spent in prehension and eating. Both converter versions performed equally well in differentiating ingestive and rumination behaviors when cows were supplemented in the barn or when grazing and supplementation activities were combined. For grazing cows, with no supplementation, more reliable results for the total number of eating chews, rumination chews, prehension bites, and time spent in these activities were obtained, by using the RumiWatch Converter 0.7.3.11. In light of these findings, further research is warranted to improve the accuracy of the RWS and to allow a differentiation between mastication chews and prehension bites while eating.
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Bovinos/fisiologia , Comportamento Alimentar , Arcada Osseodentária/fisiologia , Mastigação , Ração Animal , Animais , Suplementos Nutricionais , Ingestão de Alimentos/fisiologia , Feminino , Lactação , Silagem/análise , Suíça , Zea maysRESUMO
The aims of this study were to determine whether: (i) the jaw motor system develops a new pattern of jaw movement and/or jaw-muscle activity after resolution of an acute episode of jaw-muscle pain; and (ii) if jaw-muscle activity and jaw-movement features change progressively with repetition of a chewing sequence. Jaw movement and jaw muscle (masseter, anterior temporalis, and digastric) activity were recorded during free and rate-standardized chewing in eight asymptomatic participants (pain infusion group), before and at three time blocks up to 45 min after a single 0.2-ml bolus infusion of 5% hypertonic saline into the right masseter muscle. The same procedure, without infusion, was performed in another eight participants (control group). There were no significant main effects of group on jaw movement and muscle activity, suggesting that there were no persistent post-pain effects on chewing. Across groups, repetitions of free and unstandardized chewing movements were associated with progressive increases in velocity and amplitude of jaw movement and masseter and temporalis electromyographic (EMG) activity. These findings suggest that factors unrelated to pain, such as practice effects, may be playing a role in the changes in jaw movement and jaw-muscle activity observed after resolution of an acute episode of jaw-muscle pain.
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Dor Facial/fisiopatologia , Arcada Osseodentária/fisiologia , Músculo Masseter/fisiologia , Mastigação/fisiologia , Mialgia/fisiopatologia , Adulto , Eletromiografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Movimento , Medição da Dor , Solução Salina HipertônicaRESUMO
OBJECTIVE: In this study, the authors investigated the modulation of the masticatory path at the mandibular first molar during natural chewing of a hard gummy jelly in adults with normal occlusion. METHODS: The unilateral mastication sequence was divided into three stages, and the masticatory path of the mandibular first molar on the working side was analyzed at 2.0, 3.0, 4.0, and 5.0 mm vertical slice levels below the intercuspation in the frontal and sagittal views. RESULTS: In the frontal view, the closing and opening angles and cycle width of the final stage at 3.0, 4.0, and 5.0 mm slice levels were smaller and narrower than those of the initial stage, although those at the 2.0 mm slice level were little changed. DISCUSSION: Masticatory paths of the mandibular first molar at slice levels greater than 3.0 mm were evidently modulated to adapt to the changing properties of the food, and those at the 2.0 mm slice level remained stable throughout the masticatory sequence.
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Doces , Mandíbula/fisiologia , Mastigação/fisiologia , Dente Molar/fisiologia , Feminino , Dureza , Humanos , Registro da Relação Maxilomandibular/instrumentação , Masculino , Movimento , Fotografação/instrumentação , Propriedades de Superfície , Fatores de Tempo , Adulto JovemRESUMO
Jaw-closing movements are basic components of physiological motor actions precisely achieving intercuspation without significant interference. The main purpose of this study was to test the hypothesis that, despite an imperfect intercuspal position, the precision of jaw-closing movements fluctuates within the range of physiological closing movements indispensable for meeting intercuspation without significant interference. For 35 healthy subjects, condylar and incisal point positions for fast and slow jaw-closing, interrupted at different jaw gaps by the use of frontal occlusal plateaus, were compared with uninterrupted physiological jaw closing, with identical jaw gaps, using a telemetric system for measuring jaw position. Examiner-guided centric relation served as a clinically relevant reference position. For jaw gaps ≤4 mm, no significant horizontal or vertical displacement differences were observed for the incisal or condylar points among physiological, fast, and slow jaw-closing. However, the jaw positions under these three closing conditions differed significantly from guided centric relation for nearly all experimental jaw gaps. The findings provide evidence of stringent neuromuscular control of jaw-closing movements in the vicinity of intercuspation. These results might be of clinical relevance to occlusal intervention with different objectives.
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Oclusão Dentária , Mandíbula/fisiologia , Adulto , Relação Central , Eletromiografia , Feminino , Humanos , Incisivo/anatomia & histologia , Masculino , Mandíbula/anatomia & histologia , Côndilo Mandibular/anatomia & histologia , Músculo Masseter/inervação , Músculo Masseter/fisiologia , Movimento , Contração Muscular/fisiologia , Junção Neuromuscular/fisiologia , Amplitude de Movimento Articular/fisiologia , Telemetria/instrumentação , Músculo Temporal/inervação , Músculo Temporal/fisiologia , Fatores de Tempo , Ultrassom/instrumentaçãoRESUMO
Monitoring rumination behavior serves multiple purposes in feeding and herd management of dairy cows. The process of calving is a major event for cows, and a detailed understanding of alterations in behavioral patterns of animals in the time around calving is important in calving detection. The objective of this study was to describe the short-term changes in rumination patterns in dairy cows immediately before and after parturition. In total, 17 cows were fitted with rumination sensors that were able to monitor rumination time, number of rumination boli, and number of rumination jaw movements. Rumination time was decreased in the last 4h antepartum and in the first 8h postpartum. Cows stopped ruminating 123 ± 58 min (mean ± standard deviation) before calving and resumed ruminating 355 ± 194 min after calving. The number of rumination jaw movements and boli per day were decreased in the 24-h period postpartum. Rumination rate, the number of rumination jaw movements per rumination minute, and the number of boli per rumination minute changed little around calving. The calving event primarily influenced the duration and frequency of various rumination characteristics but not rumination intensity. Among detected characteristics, rumination time showed the greatest potential for monitoring of calving events.
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Bovinos/fisiologia , Digestão/fisiologia , Parto , Período Periparto , Animais , Ingestão de Alimentos , Feminino , GravidezRESUMO
Scissors-bite is a malocclusion characterised by buccal inclination or buccoversion of the maxillary posterior tooth and/or linguoclination or linguoversion of the mandibular posterior tooth. This type of malocclusion causes reduced contact of the occlusal surfaces and can cause excessive vertical overlapping of the posterior teeth. This case-control study is the first to evaluate both masticatory jaw movement and masseter and temporalis muscle activity in patients with unilateral posterior scissors-bite. Jaw movement variables and surface electromyography data were recorded in 30 adult patients with unilateral posterior scissors-bite malocclusion and 18 subjects with normal occlusion in a case-control study. The chewing pattern on the scissors-bite side significantly differed from that of the non-scissors-bite side in the patients and of the right side in the normal subjects. These differences included a narrower chewing pattern (closing angle, P < 0.01; cycle width, P < 0.01), a longer closing duration (P < 0.05), a slower closing velocity (P < 0.01) and lower activities of both the temporalis (P < 0.05) and the masseter (P < 0.05) muscles on the working side. In 96% of the patients with unilateral posterior scissors-bite, the preferred chewing side was the non-scissors-bite side (P = 0.005). These findings suggest that scissors-bite malocclusion is associated with the masticatory chewing pattern and muscle activity, involving the choice of the preferred chewing side in patients with unilateral posterior scissors-bite.
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Má Oclusão/fisiopatologia , Músculo Masseter/fisiopatologia , Mastigação/fisiologia , Músculo Temporal/fisiopatologia , Adulto , Estudos de Casos e Controles , Eletromiografia , Feminino , Humanos , Masculino , Movimento/fisiologia , Adulto JovemRESUMO
It is known that maximum bite force has various influences on chewing function; however, there have not been studies in which the relationships between maximum bite force and masticatory jaw movement have been clarified. The aim of this study was to investigate the effect of maximum bite force on masticatory jaw movement in subjects with normal occlusion. Thirty young adults (22 men and 8 women; mean age, 22.6 years) with good occlusion were divided into two groups based on whether they had a relatively high or low maximum bite force according to the median. The maximum bite force was determined according to the Dental Prescale System using pressure-sensitive sheets. Jaw movement during mastication of hard gummy jelly (each 5.5 g) on the preferred chewing side was recorded using a six degrees of freedom jaw movement recording system. The motion of the lower incisal point of the mandible was computed, and the mean values of 10 cycles (cycles 2-11) were calculated. A masticatory performance test was conducted using gummy jelly. Subjects with a lower maximum bite force showed increased maximum lateral amplitude, closing distance, width and closing angle; wider masticatory jaw movement; and significantly lower masticatory performance. However, no differences in the maximum vertical or maximum anteroposterior amplitudes were observed between the groups. Although other factors, such as individual morphology, may influence masticatory jaw movement, our results suggest that subjects with a lower maximum bite force show increased lateral jaw motion during mastication.
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Força de Mordida , Mandíbula/fisiologia , Mastigação/fisiologia , Adulto , Oclusão Dentária , Feminino , Alimentos , Dureza , Humanos , MasculinoRESUMO
A posterior cross-bite is defined as an abnormal bucco-lingual relationship between opposing molars, pre-molars or both in centric occlusion. Although it has been reported that patients with unilateral posterior cross-bite often show unique chewing patterns, the relationship between the form of cross-bite and masticatory jaw movement remains unclear in adult patients. The objective of this study was to investigate masticatory jaw movement among different forms of cross-bite. One hundred and one adults were recruited in this study: 27 had unilateral first molar cross-bite (MC group); 28, unilateral pre-molar cross-bite (PC group); 23, anterior cross-bite (AC group); and 23, normal occlusion (control group). Masticatory jaw movement of the lower incisor point was recorded with six degrees of freedom jaw-tracking system during unilateral mastication. Our results showed that the reverse chewing ratio during deliberate unilateral mastication was significantly larger in the MC group than in the PA (P < 0.001), AC (P < 0.001) and control (P < 0.001) groups. These findings suggest that compared to the anterior or pre-molar cross-bite, the first molar cross-bite is more closely associated with a higher prevalence of a reverse chewing cycle.
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Dente Pré-Molar/fisiopatologia , Má Oclusão/fisiopatologia , Mastigação/fisiologia , Dente Molar/fisiopatologia , Feminino , Humanos , Masculino , Adulto JovemRESUMO
The aim was to investigate the effects of isotonic resistance exercise on the electro-myographic (EMG) activity of the jaw muscles during standardised jaw movements. In 12 asymptomatic adults surface EMG activity was recorded from the anterior temporalis and masseter muscles bilaterally and the right anterior digastric muscle during right lateral jaw movements that tracked a target. Participants were randomly assigned to a Control group or an Exercise group. Jaw movement and EMG activity were collected (i) at baseline, before the exercise task (pre-exercise); (ii) immediately after the exercise task (isotonic resistance at 60% MVC against right lateral jaw movements); (iii) after 4 weeks of a home-based exercise programme; and, (iv) at 8-weeks follow-up. There were no significant within-subject or between-group differences in the velocity and amplitude of the right lateral jaw movements either within or between data collection sessions (P > 0.05). However, over the 8 weeks of the study, three of the tested EMG variables (EMG Duration, Time to Peak EMG from EMG Onset, and Time to Peak EMG activity relative to Movement Onset) showed significant (P < 0.05) differences in the five tested muscles. Many of the significant changes occurred in the Control group, while the Exercise group tended to maintain the majority of the tested variables at pre-exercise baseline values. The data suggest a level of variability between recording sessions in the recruitment patterns of some of the muscles of mastication for the production of the same right lateral jaw movement and that isotonic resistance exercise may reduce this variability.
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Eletromiografia , Contração Isotônica/fisiologia , Arcada Osseodentária/fisiologia , Mastigação/fisiologia , Músculos da Mastigação/fisiologia , Movimento/fisiologia , Adulto , Exercício Físico/fisiologia , Feminino , Humanos , MasculinoRESUMO
This is a case report about the successful orthodontic treatment of a bilateral cleft lip and palate patient by using a combination of bone grafting and subsequent prosthodontic rehabilitation. An adult patient with a bilateral cleft lip and palate presented with a concave profile, anterior and lateral crossbite, a markedly deep overbite, and residual bilateral alveolar clefts. His jaw movement patterns were unstable and irregular due to his collapsed bite. Orthodontic treatment with bilateral bone grafting improved his concave profile by downward and backward rotation of the mandible within the freeway space, and optimum occlusion and functionally stable and smooth jaw movements were obtained. After a 6-year retention period, no skeletal relapse could be detected, and his occlusal stability was satisfactory.