Search Results (4)

Background: Unilateral mastication (UM), defined as the habitual use of one side of the mouth for chewing, has been linked to various craniofacial asymmetries and systemic effects. This study aims to explore the relationship between UM and nasal airway asymmetry, investigating whether a habitual chewing side correlates with a narrowed nostril. These findings provide a preliminary understanding of how chewing practices might impact craniofacial anatomy and respiratory health. Methods: A pilot study involving 24 adults aged 18 and older was conducted. Inclusion criteria excluded individuals with prior orthodontic treatment or edentulism. The habitual chewing side was determined through self-report and direct observation of chewing gum activity. Nostril dimensions were assessed using ImageJ^® 1.54 software by blinded observers. Statistical analysis, including Fisher’s exact test and Kruskal-Wallis test, was performed using R version 4.4.1 to examine associations between the chewing side and nasal asymmetry. Results: Half of the participants (50%) preferred the right side for chewing. A significant association was found between the chewing side and the smaller nostril (p < 0.001). Participants with a smaller right nostril consistently preferred chewing on the right side, with a large effect size (ϕ = 0.845). No significant differences in age were observed across nostril groups (p = 0.47). Conclusions: This study reveals a strong association between unilateral mastication and nasal airway asymmetry, highlighting the potential role of chewing habits in influencing craniofacial development. These findings emphasize the need for further longitudinal studies to explore the systemic and aesthetic implications of habitual chewing patterns. Full article

Chewing improves visuospatial performance through locus coeruleus (LC) activation. The effects of bilateral and unilateral mastication were investigated in subjects showing different degrees of asymmetry in masseter electromyographic (EMG) activity during clenching and in pupil size at rest (anisocoria), which is a proxy of LC imbalance. Correlations between performance changes and asymmetry values were found in males, but not in females. Among males, subjects with low asymmetry values (balanced-BAL) were more sensitive than those with high asymmetry values (imbalanced-IMB) to bilateral and unilateral chewing on the side with higher EMG activity (hypertonic). The opposite was true for hypotonic side chewing. BAL subjects were sensitive to unilateral chewing on both sides, while in IMB subjects, hypertonic side chewing did not influence performance in either males or females. Bilateral chewing elicited larger effects in BAL subjects than in IMB subjects, exceeding the values predicted from unilateral chewing in both groups. Finally, pupil size and anisocoria changes elicited by chewing were correlated with asymmetry values, independent of sex. Data confirmed the facilitation of visuospatial performance exerted by chewing. Trigeminal asymmetries modulate the chewing effects, making occlusal rebalancing an appropriate strategy to improve performance. Full article

Temporomandibular disorders are a common pathology affecting up to 70% of the population, with a maximum incidence in young patients. We used a sample of twenty patients recruited in the Maxillofacial Surgery Service of the University Hospital of Salamanca (Spain), who met the inclusion criteria, with unilateral painful symptomatology of more than three months’ duration. All patients were randomly treated by intramuscular and intra-articular injections of botulinum toxin (100 U) in eight predetermined points. Pain symptomatology was assessed by the visual analog scale (VAS) at the different locations, together with joint symptomatology, at baseline and six weeks after treatment. Adverse effects were also evaluated. In 85% of the patients, pain upon oral opening improved and 90% showed improvement in pain upon mastication. A total of 75% of the patients reported improvement in joint clicking/noise. Headaches improved or disappeared in 70% of the patients treated. Despite the limitations of the study and the preliminary results, intramuscular and intra-articular infiltrations with botulinum toxin were effective in the treatment of symptoms associated with temporomandibular disorders (TMDs), with minimal adverse effects. Full article

In the formulation of an orthodontic treatment plan, the three-dimensional analysis of the dental arches represents a fundamental moment for the evaluation of all the morphological parameters necessary in order to have a correct and complete diagnosis. In this regard, the study of the dental arches on the horizontal plane is sometimes neglected or not thorough enough. When evaluating the transverse dimensions of the dental upper arche, the presence of an asymmetry is frequently found, and it means that an hemiarch is larger than the other. Furthermore, any variation in one of the three planes of space always involves an alteration also on the other two planes in order to have compensation. The morphology of a bone segment depends on various factors, mainly genetical, acquired and environmental. Regarding the environmental factors, the function determines the morphology, but this in turn determines the function. In the case of unilateral mastication, the upper maxilla will be asymmetrical, so growing patients will have compensation on other skull bones. From these considerations arises the need for a careful study of the horizontal plane of the maxilla in the presence of a malocclusion during diagnostic evaluations. These asymmetries, however, must be evaluated and quantified in the diagnostic phase in order to formulate a correct plan of treatment. The aim of this work is to demonstrate that there are almost always transverse asymmetries of the maxilla, albeit of a slight entity, even in healthy and apparently symmetrical subjects. Full article