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Background/purpose: Previous studies have suggested that functional dominance in one part of the body can be correlated with functional dominance in another part. Thus, the present research aimed to determine whether brain laterality (handedness, footedness, earedness, and eyedness) was related to mixing ability and chewing side preference.
Materia...
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Context 1
... measure brain laterality as defined by the most frequently used side of the hands, feet, eyes, and ears, the experimental method suggested by Nissan et al 3,4 was redesigned and reconstructed to fit the location and cir- cumstances of the study. The brain laterality tests were preceded by volunteers indicating their brain laterality through a survey (Table 1). ...
Citations
... The side of the body that is used most often is considered to be the dominant side of the organ (i.e., sidedness), and the organs that have sidedness are the hands, feet, eyes, and ears [2]. Studies have been conducted from the perspective of genetic factors [3,4] given that sidedness is determined by the brain [1,5]. Moreover, the sidedness of organs that we are aware of and what was determined by the brain often coincide [6]. ...
... PCS is more prevalent on the right than the left side in adults [12][13][14]. There is a relationship between PCS and the sidedness of various organs determined by the brain (e.g., dominant hand, foot, eye, and ear) [1,5], with some reports suggesting a strong relationship with the dominant ear [15,16], while others indicate that there is no association [17]. Moreover, a significant relationship between PCS, tongue movement, and the concomitant activation of the primary sensorimotor cortex (S1/M1) has been demonstrated by functional magnetic resonance imaging (fMRI), suggesting that the activation of the S1/M1 was significantly greater on the side contralateral to PCS [18,19]. ...
... In this study, the average duration of orthodontic treatment was 34 months. PCS, the dominant side (laterality) of mastication, is principally determined by brain dominance, such as the dominant hand, foot, eye, and ear [1,5]. Handedness reflects the inherent specialization in the cerebral hemispheric control processes (dominant system for controlling limb trajectory and non-dominant system for controlling limb position) [44]. ...
Whether orthodontic treatment can change the preferred chewing side (PCS) is unknown. This study examined (1) if the PCS changes after orthodontic treatment and (2) which factors contribute to this change. Two hundred fifty patients who visited the orthodontic clinic at Tokyo Medical and Dental University Hospital between 2017 and 2020 were included in the study. Mandibular kinesiograph (MKG) was taken at pre- and post-treatment, and PCS was determined. Patients who showed a change in PCS to the opposite side and those who showed no change in PCS at post-treatment were pooled into the PCS-changed and PCS-unchanged groups, respectively. The demographic, clinical, and cephalometric parameters were compared between the groups. Significant factors associated with changes in were of age < 20 years at the beginning of orthodontic treatment (odds ratio (OR), 2.00), maximum lateral mandibular movement to PCS ≥ 10.0 mm at pre-treatment (OR, 6.51), and change in occlusal canting of ≥1.0° (OR, 2.72). The predicted probability of change in PCS was 13.2%, 36.0%, and 67.5% for no factor, one factor, and two factors associated with PCS change, respectively. Orthodontic treatment may change PCS due to patient age, maximum lateral mandibular movement to PCS, and change in occlusal canting.
... A mastigação é uma importante função do sistema estomatognático controlada pelo sistema nervoso central [10,18,22], estando diretamente relacionada à digestão, pois, quanto maior a degradação mecânica dos alimentos, maior será a ação enzimática sobre eles [12]. O ciclo da mastigação envolve uma sequência precisa de movimentos de abertura e fechamento da mandíbula, proporcionados pela ação coordenada da musculatura mastigatória somada ao movimento dos lábios, bochechas e língua [23]. ...
A ação da musculatura mastigatória caracteriza diferentes padrões mastigatórios que influenciam o desenvolvimento craniofacial. À medida que a mandíbula é submetida a diferentes cargas mecânicas, alterações morfológicas no osso podem ocorrer. Objetivo: Avaliar, por meio de exames de tomografia computadorizada de feixe cônico (TCFC), a estrutura óssea da região posterior do corpo mandibular em indivíduos com diferentes padrões mastigatórios. A hipótese do estudo foi que as assimetrias ósseas mandibulares estão associadas a padrões assimétricos de mastigação. Material e métodos: Selecionaram-se para o estudo 23 indivíduos com idade superior a 18 anos. O padrão mastigatório foi determinado por intermédio do método visual, no qual os indivíduos foram instruídos a mastigar de forma habitual um pedaço de pão francês; 17 indivíduos (73,9%) apresentaram mastigação unilateral preferencial e seis (26,1%) apresentaram mastigação bilateral. Nos exames de TCFC, dez cortes transversais do corpo mandibular foram realizados na distal de cada dente, de canino até segundo molar, onde as dimensões do processo alveolar e a espessura do osso cortical foram medidas. Resultados: Não houve diferença significativa entre os lados preferencial e não preferencial de mastigação de indivíduos com padrão mastigatório unilateral preferencial. Em indivíduos com padrão mastigatório bilateral, ao comparar os lados direito e esquerdo, houve diferença significativa na espessura do processo alveolar no primeiro pré-molar, primeiro molar e segundo molar e na espessura cortical inferior do segundo pré-molar. Conclusão: Não foi possível estabelecer uma relação entre a função mastigatória e a estrutura óssea. Sendo assim, a hipótese de que as assimetrias ósseas mandibulares estão associadas a padrões assimétricos de mastigação não foi confirmada.
... Generally, people tend to masticate unilaterally 31) , which causes unbalanced facilitation of soft tissues around the temporomandibular joints 32) and osseous morphology 33) , resulting in less activation of the hippocampus and amygdala 34) . Second, bilateral masticatory training using the intraoral device is relatively safe for healthy volunteers because no adverse events were reported in this study. ...
Objectives: This study aimed to explore the short-term effects of bilateral masticatory training using an intraoral device on memory and concentration, which is an advanced form of Gochi, compared to the unilateral form with gum.Methods: Thirty young healthy participants (age, 16–30 years) were screened and randomly assigned to one of two sequences in a crossover design. The participants assigned to sequence A (n=15) performed bilateral mastication using an intraoral device with a total of 300 taps, followed by unilateral mastication using gum with the same number of repetitions and frequency, separated by a 7-day washout period. A reverse order was used for sequence B. The primary and secondary outcomes were the digit span test result and the symbol digit modality test and the word list recallresults, respectively, which were conducted before and after each intervention.Results: Symbol digit modality test scores increased by 12.03±8.33 with bilateral mastication, which was significantly higher than that obtained with chewing gum (5.17 points;95% confidence interval: 0.99, 9.34; p<0.05). Changes in the digit span test and word list recall scores were not significantly different between the two groups. In the digit span test forward, symbol digit modality test, and word list recall test, bilateral mastication was not inferior to unilateral mastication in improving memory and concentration.Conclusions: Bilateral masticatory exercises using an intraoral device are not inferior to unilateral mastication with gum for improving memory in healthy young individuals. Further research is needed to determine the efficacy of bilateral masticatory training on cognitive function.
... However, brain laterality can be explained by the side of functional preference rather than the efficiency of mastication. Thus, the higher activation value was used in those subjects who presented with bilateral activation [42]. • The activation pattern during chewing at Baseline was too variable across the subjects to draw any conclusive pattern of activation. ...
Purpose: This study aims to evaluate the effect of rehabilitation with complete dentures versus implant-retained overdenture on activity in various parts of the brain cognition in a geriatric edentulous population via Functional MRI (fMRI) studies and the Mini-Mental State Examination (MMSE).
Methods: Ten completely edentulous patients were rehabilitated with both complete dentures and two-implant retained overdentures for three months each. fMRI studies were performed for each modality during chewing and recall tasks at three time periods: T0: Completely Edentulous(CE) T1: after three months of wearing Conventional Complete Dentures(CD) and T2: after three months of wearing Implant-retained Overdentures (IOD). The Z scores obtained from the fMRI at these phases of examination were tabulated and correlated with MMSE scores obtained at the corresponding time periods.
Results: Z scores obtained during the memory recall tasks at T2 were the greatest (Prefrontal Cortex (p=0.059) and Hippocampus (p=0.036). The MMSE scores obtained were significantly higher for the IODs when compared to the CDs and Baseline values (p < 0.05)
Conclusion: IODs may potentially result in superior sensory feedback in edentulous patients and lead to improved cognitive performance when compared to conventional complete dentures.
... A previous study reported that the habitual chewing side influences masticatory ability 14) . Conversely, in 2017, Lee et al. 15) reported that brain laterality could be explained by the fact that the preferred functional side (preference of the hands, eyes, ears, and feet, and survey) has a positive correlation with chewing preference. In addition, they concluded that brain dominance is correlated with chewing preference, but does not affect the efficiency of mastication. ...
Purpose: To establish ideal occlusal contacts for fixed prostheses, the relationship between masticatory efficiency and occlusal contacts in dentulous adults should be investigated using suitable experimental foods. In this study, masticatory efficiency, especially fragmentation ability at the early stage of mastication, in healthy adults was evaluated using dried raisins that deform before fragmentating it at an early stage of mastication. In addition, the influence of occlusal conditions on masticatory efficiency was investigated.
Material and Methods: The subjects were 16 healthy volunteers (men: 11, women: 5), and their ages ranged between 25 and 61 years (mean ± standard deviation: 38.8 ± 10.50 years). The subject’s habitual masticatory side was determined by observing the translation of a raisin from the center of the tongue dorsum. The testing food was dried raisins, which can withstand high strain before crack propagation, and subsequently fragmentation begins. The number of chews, when fragmentation of raisin was observed, was recorded as a fragmentation ability index. The images of the occlusal records in intercuspal position were analyzed using the silicone black technique. Occlusal condition in molar regions was evaluated by the following three parameters, which were defined by the interocclusal distance: number of contacts, 0-50 μm thickness; tight contact areas: 0-50 μm thickness; and intermediate contact areas: 50-100 μm thickness. The points of inquiry were as follows: 1. fragmentation ability index, 2. number of contacts, 3. tight contact area, and 4. intermediate contact area. The data were analyzed with a Spearman’s test.
Result: There was a negative correlation between the fragmentation ability index and contact areas: tight contact areas: r=−. 433, p=. 013 and intermediate contact areas: r=−. 608, p=. 000. In addition, the fragmentation ability index was negatively correlated with the number of contacts (r=−. 481, p=. 005).
Conclusion: The results of this study indicate that our method has the potential to evaluate masticatory efficiency in dentulous adults.
... Laterality preferences are expressed by the function of the hands and other organs, e.g. feet, ears and eyes, as an expression of the brain laterality in terms of handedness, footedness, earedness, and eyedness [11]. The design of products and processes should consider the laterality preferences of feet, ears and eyes, together with the handedness of the users. ...
Pain, fatigue and musculoskeletal disorders may be the consequence of awkward and inadequate postures caused by the improper design of work activities and poorly designed workstations. The good design of workstations following the ergonomics principles is necessary to avoid these adverse effects. This study aimed to define a set of ergonomics principles for the design of assembly workstations for both left-handed and right-handed users. An experimental study was performed at the university laboratory involving both left-handed and right-handed users for the assembly of a centrifugal electric pump. The experimental study proved that left-handed and right-handed users differently interact with the objects in the space. Four fundamental ergonomics principles for the design of assembly workstations for both left-handed and right-handed users have been defined, based on the results of the laboratory test. The proposed principles help designers and practitioners during the design of assembly workstations, proving the importance of the ambidextrous design of workstations.
... However, discrepancies in occlusal force distribution in the sagittal dimension on the left and right sides might contribute; Some patients may be right-side chewers or left-side chewers. Chewing preferences may bring about asymmetries in force distribution in the sagittal dimension, and may be influenced by functional dominance, temporomandibular disorders, muscle activity, use of dentures, etc. [25,26]. Left-side chewing activates the supplementary motor area of the brain, while right-side chewing activates the inferior frontal gyrus and inferior parietal lobule [27]. ...
... Theoretically, this suggests that a decrease in the activation of the frontal gyrus and inferior parietal lobe areas could lead to memory loss. A study by Lee, et al. [26] reported that mastication ability does not differ between dominant and non-dominant sides, and it was suggested that brain dominance correlates with chewing preference given to an individual's oral health in order to maintain or even improve mastication, which could lead to stabilization or even improvement of cognition. ...
Objective: The aim of this study was to evaluate the relationship between the direction of unilateral chewing preference observed in fully dentate bruxist and non-bruxist groups (with fully dentate and missing and/or restored teeth) and brain laterality. Methods: Brain laterality of the subjects (n=132) was determined based on responses to questions about extremity and sensory preferences. The reliable visual analogue scale (VAS), Kazazoğlu’s method and the sunflower seed shell cracking test were used to determine chewing side preference. Results: Chewing side preferences determined by VAS were not associated with brain laterality. While extremity and sensory preferences were predominantly right-sided (dominant left hemisphere) in all groups, the frequency of the left side chewing was found to be high only in bruxers (p > 0.05). No significant association was found between the results of VAS and other techniques (p > 0.05). Conclusion: The left chewing side preference is observed more frequently in bruxers, suggesting that different central and peripheral mechanisms may be involved in bruxers.
Purpose:
The lateralization can influence the choice of occlusion scheme, patient comfort and success of the prosthesis. The existence of favored masticatory side in complete denture patients and its influence with various occlusal schemes is less analyzed in the literature. The study objective was to compare the masticatory and hemispheric laterality in complete denture subjects rehabilitated with 2 different occlusal schemes at different time intervals.
Methodology:
The cohort study recruited 26 patients in each group of balanced and non-balanced occlusion with definitive criteria. Conventional procedures were followed in denture fabrication. The hemispheric and masticatory laterality for all participants were established at 0,1,3- and 6-month intervals. The laterality was categorized as preferred chewing side (CPCS), predominant preferred chewing side (PPCS) and observed preferred chewing side (OPCS). The data on chewing side preference was analyzed by chi square test. (α = 0.05).
Results:
Right side preference was predominant in 86.1% of non-balanced and 60.1% of balanced occlusion participants. The side preference among the 2 laterality and across time interval decreased in masticatory laterality of balanced occlusion participants (P < .05) when compared to non-balanced occlusion. (P > .05).
Conclusion:
The balanced occlusion dentures had lesser masticatory side preference when compared to non-balanced occlusion complete denture.
Aim: In our study, the relationship between mandible coronoid process and other mandible morphometric parameters in dry bones and it is aimed to compare these data between the sides. Materials and Methods: In the anatomy laboratory, 22 mandible from the bone collection were photographed in three different ways, from right-left lateral and posterior, using a digital camera. Measurements were performed on digital images using Image J software. Morphometric parameters of coronoid process and morphometric parameters of mandible ramus and body were determined. Coronoid process types were hooked, triangular, round and square. The parameters were compared between the two sides and correlation analysis was performed. Results: There was no significant difference between the right and left sides in all parameters. There was no difference between the parties in the percent distribution of processus coronoideus types. There was a high correlation between processus coronoideus area and processus coronoideus height on both sides (p <0.001). Correlation values of the processus coronoideus parameters on the right side were higher than the left side. Conclusion: For the differences in the morphometric parameter values between the coronoid process between the sides, further studies should be conducted in the developmental process up to childhood, adolescence and adulthood. Furthermore, further studies are needed to evaluate the effects of chewing side preference on processus coronoideus and to assess the differences in side/gender.
