BACKGROUND: The literature is unclear about how the different attachment systems for overdentures impact the maximum bite force, the masticatory efficiency and how this impact in the oral health self-perception in patients.
OBJECTIVE: To evaluate the effect of two attachment systems (O-ring and Locator) for mandibular overdenture using single implant on quality of life, maximum bite force (BF) and masticatory efficiency (ME).
METHODS: Twenty-eight completely edentulous denture wearers with a mandibular symphysis implant were randomly selected and allocated into two groups in a crossover study, considering O-ring and Locator attachment types. The quality of life and self-perception of oral health were assessed using the Oral Health Impact Profile (OHIP-Edent) and Geriatric Index of Determination of Oral Health (GOHAI) questionnaires, respectively. BF was measured using a gnathodynamometer and ME by chewing silicone cubes and almonds in different numbers of cycles.
RESULTS: There was no difference between the attachment systems about self-perceived oral health and impact on quality of life (p > .05). The O-ring-type system obtained a significantly higher BF than the locator-type system (p = .04). Regardless of the food chewed, no statistically significant difference was observed with the type of attachment (p > .05). The ME was directly proportional to the masticatory cycles only for almonds (p < .01).
CONCLUSIONS: Locator and O-ring inserts had a similar impact on patients\' quality of life, self-perception of oral health and ME. Additionally, the O-ring system exhibited superior properties in the BF.

BACKGROUND: Little is known about the fetal and pregnancy effects of khat chewing during pregnancy. The aim of the current study was to determine the impact of chewing khat during pregnancy on selected pregnancy outcomes in Ethiopia, 2022: A Cohort Study with a Generalized Structural Equation Modeling Analysis Approach.
METHODS: An institution-based prospective cohort study was employed in selected hospitals in eastern Ethiopia. Pregnant women who visited the selected hospitals in the study area during the study period that fulfilled the eligibility criteria were included until a sample size (344) was fulfilled. The main outcomes studied in the present study were preterm birth and low birth weight. Data were collected through anthropometric and clinical measurements, and interviewers administered questionnaires. The survival analysis and generalized linear model analysis were performed to estimate the crude and adjusted relative risk and attributable risk. The Generalized Structural Equation Modeling (GSEM) analysis was performed using the Statistical software for data science (Stata) \'GSEM\' command to examine the mediation effect.
RESULTS: The risk of occurrence of preterm birth was significantly higher among khat chewers [adjusted relative risk (aRR) = 2.19; 95%CI 1.21-3.96]. In further analysis after adjusting for gestational hypertension and cesarean delivery, the regression coefficient of khat chewing during pregnancy on preterm birth has been decreased in size from path n, β = 0.37, p<0.001 to path n\', β = 0.15, p<0.005. The risk of occurrence of low birth weight among khat chewers was significantly higher (aRR = 4.17; 95%CI 2.11-8.25). In further analysis after adjusting for gestational hypertension, cesarean delivery, preterm birth and maternal anemia, the regression coefficient of khat chewing during pregnancy on low birth weight has been decreased in size from path q, β = 0.4, p<0.001 to path q\', β = 0.2, p<0.001.
CONCLUSIONS: Overall, the present study revealed that khat chewing is not only a worry of the current population but also a public health concern of the generation affecting unborn fetuses.

BACKGROUND: Masticatory function seems to play a role in the aetiology of obesity. However, literature on the association between oral myofunctional status and overweight and obesity in children and adolescents is scarce and contrasting.
OBJECTIVE: To compare masticatory performance, orofacial myofunctional status and tongue strength and endurance between children and adolescents with overweight and obesity and those with normal weight.
METHODS: Thirty children and adolescents with overweight and obesity and 30 subjects with normal weight matched for age and sex were recruited. All subjects were evaluated with the Test of Masticating and Swallowing Solids in Children (TOMASS-C) for masticatory performance and with the Italian Orofacial Myofunctional Evaluation with Scores (I-OMES) for the orofacial myofunctional status. Anterior and posterior maximum tongue pressures and tongue endurance were measured. Parents-reported (PRO) duration of meals was recorded. Data were compared between the groups through the paired samples t-test or the Wilcoxon signed-rank test.
RESULTS: Children and adolescents with overweight showed significantly lower number of bites (p = .033), lower I-OMES scores (p < .05), and shorter meal duration (p = .005) compared to their peers with normal weight. No significant differences were found between the two groups for the number of swallows, the number of masticatory cycles and the total time of the TOMASS-C, and none of the tongue pressure measurements.
CONCLUSIONS: Eating in children and adolescents with overweight and obesity is characterised by a larger bolus sizes and shorter PRO meal duration. Additionally, overweight and obesity seem to be associated with poorer orofacial skills and structures in the paediatric population.

UNASSIGNED: The band and loop space maintainer is used to maintain the missing space of deciduous molars which are lost early. When the second deciduous molar is lost prematurely, the stress on the first permanent molar during different degrees of development may vary when it is the abutment. The design and use of the space maintainer may also lead to damage of the loop. The purpose of this article is to use the finite element method to study the stress on the first permanent molar and the loop with or without occlusal contact, with the first permanent molar of four different degrees of development serving as the abutment. We aimed to guide the clinical design and use of the space maintainer.
UNASSIGNED: We developed finite element models of the mandibular first permanent molar and the band and loop space maintainer, and simulated alveolar bone, periodontal ligament (PDL), enamel and dentin. The four developmental stages were 1/2 (I), 2/3 (II), 3/4 (III) and full development (IV). Ansys Workbench was used to analyze the effects of root development and occlusal contact between the loop and the opposite jaw on abutment teeth and the loop. Abutment teeth were statically loaded vertically and obliquely with a force of 70 N. The loop was statically loaded vertically with a force of 14 N. The stress on all structures and the displacement trends of the loop were calculated.
UNASSIGNED: The stress on enamel, dentin, PDL and alveolar bone were similar, and the concentration was consistent. But if there was occlusal contact, the loop produced maximum displacement at the near middle edge of contact with the anterior teeth. When the loop was in occlusal contact with the opposing occlusal tooth, the peak value of the equivalent stress on the space maintainer under vertical load was: group I > group IV > group III > group II, and the maximum principal stress peak change was: group I > group III > group II > group IV. The change of the equivalent stress peak value of the loop under oblique load was: group I > group III > group IV > group II, and the maximum principal stress peak change was: group III > group I > group II > group IV. When the loop was not in occlusal contact with the opposing occlusal tooth, the peak value of the equivalent stress on the space maintainer under vertical load was: group IV > group I > group II > group III, and the maximum principal stress peak change was: group IV > group I > group II > group III. The change of the equivalent stress peak value of the space maintainer under oblique load was: group I > group IV > group II > group III, and the maximum principal stress peak change was: group I > group IV > group II > group III.
UNASSIGNED: Our results suggested that whenever possible, choosing the teeth with nearly complete root development as the abutment of the space maintainer is advisable. The design and use of the band and loop space maintainer should avoid occlusal contact with the occlusal teeth to prevent deformation of the loop.

UNASSIGNED: This study aimed to compare the perceived masticatory ability (PrMA) in completely edentulous patients (EDPs) with thermoplastic conventional complete dentures (CDs) versus single implant-retained mandibular overdentures.
UNASSIGNED: The current study was conducted in the outpatient Prosthodontic Clinic, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt. PrMA was evaluated in 45 completely edentulous patients (46% males, mean age 50.4 ± 4.7 years). Each patient received a thermoplastic PMMA complete denture (Polyan IC TM Bredent GmbH & Co.KG, Germany). The PrMA was evaluated at one-month and six-month intervals of denture use. An immediate loading single implant was placed into the mid-symphyseal for each patient, and the denture was adjusted. Subsequently, the PrMA was reevaluated after one month and six months. The data were collected and statistically analyzed using the SPSS@V25 to assess the changes in PrMA.
UNASSIGNED: The PrMA demonstrated improvement after six months of thermoplastic conventional denture use. However, this improvement was not statistically significant (p = 0.405). In addition, the PrMA showed a substantial increase following a single implant placement at one and six months (p < 0.001) of the overdenture use compared to the conventional denture. The PrMA insignificantly improved (p = 0.397) after six months of the single implant retained overdenture use.
UNASSIGNED: The study\'s findings indicate that using immediate loading single implant-retained mandibular overdentures significantly improved PrMA in completely edentulous patients.

OBJECTIVE: Japanese children have been shown to exhibit decreased masticatory function; however, limited evidence is available regarding the efficacy of certain food items in improving this issue. Therefore, this study examined the effects of chewing hard gummy candy on the masticatory function of Japanese children aged 6-12 years.
METHODS: The study included 26 participants (10 boys and 16 girls; mean age ± standard error = 9.3 ± 0.3 years) who were asked to chew hard gummy candy twice daily for 4 weeks at home. The lip-closing force, occlusal force, and masticatory performance of the participants were recorded before commencement (T1), 4 weeks after commencement (T2), and 4 weeks after completion (T3) of the training. Statistical analyses were performed using the Wilcoxon rank-sum test or the Wilcoxon signed-rank test with Bonferroni correction.
RESULTS: No significant differences in masticatory function by gender and age groups (defined based on mean age at T1) were observed at T1. The lip-closing and right occlusal forces increased significantly after 4 weeks of exercise, and the effects persisted for another 4 weeks after completion. The masticatory performance also improved after training, although these effects did not persist and deteriorated substantially 4 weeks after completion of the training.
CONCLUSIONS: Habitual mastication training using hard gummy candy markedly enhances masticatory function (e.g., lip-closing force, occlusal force, and masticatory performance) in Japanese children.

BACKGROUND: Current anatomical knowledge of the origin of the bucinator muscle (BM), i.e., long thin attachments on the maxilla and mandible and the pterygomandibular raphe (PMR), is not supported by anatomical dissection of this muscle. The aim of this study was therefore to investigate the detailed morphology of the BM and associated structures and to discuss its function.
METHODS: The anatomy of the BM and related structures was investigated in 15 cadaveric heads using a surgical microscope and histological analysis.
RESULTS: The inferior fibers of the BM originated from a small retromolar area (internal oblique line), which shared a common tendon with the deep tendon of the temporalis. The superior fibers of the BM originated from the maxillary tuberosity. The middle fibers originated the pterygoid hamulus. No PMR was identified in any of the specimens, but the border between the BM and superior pharyngeal constrictor muscle (SC) was clear because the muscle fibers followed different directions. Some horizontal fibers were continuous between the BM and SC.
CONCLUSIONS: Our results suggest the need to revise established accounts of the origins of the bucinator (the maxillary tuberosity, conjoint tendon of the temporalis, and pterygoid hamulus without a pterygomandibular raphe. It also needs to be noted that some of its fibers merge directly with the SC.

OBJECTIVE: To analyse the association of masticatory performance and oral health-related quality of life in a representative population of individuals residing in communities in Switzerland aged ≥ 45 years.
METHODS: In total, 100 subjects completed two dedicated and validated questionnaires on their demographic data and the Geriatric Oral Health Assessment Index. A mixing ability test was performed for assessing masticatory performance. The qualitative analysis of the test was performed by categorizing the images into five categories, while the quantitative analysis was performed via a validated custom-made software.
RESULTS: Sixty-six samples could be analysed. Participants younger than 65 years of age showed significantly less frequent chewing deficiencies (17%) compared to those 65 years and older (50%, p < 0.01). However, retired participants had chewing deficiencies significantly more frequently (8%) compared to workers (51%, p < 0.01). A statistically significant positive association of having chewing deficiency was found between employment status (p < 0.01) and the presence of restorations (p = 0.04), while GOHAI did not show any statistically significant association. Overall, the enrolled subjects displayed moderate chewing function. Masticatory performance was positively associated with the number of present restorations.
CONCLUSIONS: The enrolled subjects residing in communities in Switzerland aged ≥ 45 years displayed moderate chewing function. Their masticatory performance was positively associated with the number of present restorations but not associated with oral health related quality of life (GOHAI).

The present study aimed to assess the effectiveness and functional adverse effects of a single and multiple injections of botulinum toxin A (BoNT-A) for masseter hypertrophy (MH). Twenty-six women complaining about lower third facial enlargement due to MH, received 75 U of BoNT-A (abobotulinum toxin) in each masseter muscles. After 3 months, patients were randomly assigned to receive a second treatment session of Saline Solution: (G1; n = 11) or BoNT-A: (G2; n = 12). Muscle thickness (ultrasound), electrical activity (electromyography; EMG), masticatory performance, and subjective perception of MH were evaluated. Follow-up was performed at 1, 3 and 6 months. Muscle thickness, EMG activity, and masticatory performance were analyzed using ANOVA two-way and Sidak test as post-hoc. Masticatory performance was analyzed by the Friedman\'s test and Mann-Whitney test. Regarding inter-groups comparisons, there was a significant decrease in the left masseter muscle thickness in the G2 group at the 6 month follow-up (p < 0.02). For EMG, significant differences were evident at the 6 month assessment, with higher masseter activity for G1 (p < 0.05). For masticatory performance, no significant differences were observed throughout the study (p > 0.05) and a higher improvement in subjective perception of MH was observed in the 1 month follow-up for G2 (p < 0.05). In conclusion, BoNT-A is effective for MH, however multiple injections cause functional adverse effects in masseter muscle.

BACKGROUND: Increase in functional disability in aging societies is an international medical and public health issue. Masticatory function may be a potential risk factor for functional disability, but the role of frailty in the association has not been clarified.
METHODS: Forty thousand five hundred sixty-two community-dwelling older adults aged 65 years and over who were insured by public health insurance as of April 2018 were followed up for a median of 3.0 years. Masticatory function was categorized as good, moderate, or poor based on a self-reported questionnaire. The development of functional disability was defined as a new certification of the need for long-term care. A Cox proportional hazards model was used to calculate hazard ratios (HRs) and their 95% confidence intervals (CIs).
RESULTS: During the follow-up period, 1,397 individuals experienced functional disability. After adjusting for age, sex, comorbidities, medical history, and lifestyle behaviors, the HR for incident functional disability was significantly higher in the moderate and poor groups compared to the good group (moderate, HR 1.21 [95% CI, 1.07-1.37]; poor, HR 1.64 [95% CI, 1.03-2.62]). However, after additional adjustment for frailty-related factors-namely, underweight, regular exercise, and gait speed-the association was attenuated in both the moderate group (HR 1.06 [95% CI, 0.94-1.21]) and the poor group (HR 1.51 [95% CI, 0.94-2.41]).
CONCLUSIONS: Masticatory dysfunction was significantly associated with incident functional disability in a community-dwelling older Japanese population. Our findings suggest that masticatory dysfunction may be a surrogate of frailty rather than a direct cause of functional disability.