Of the article: evaluation of the masticatory efficiency of children with stainless steel crowns: a pilot cross-sectional split-mouth study.

BACKGROUND: Stainless steel crowns (SSCs) are commonly employed to restore the posterior teeth of children and over the years, they are available with improved anatomical shapes. This study was conducted to evaluate and assess the effect of the placement of SSCs on the masticatory efficiency of children. METHODS: This pilot cross-sectional split-mouth study assessed masticatory efficiency in children aged 6-11 years. Fifteen participants, each with stainless-steel crowns placed unilaterally at least one month prior, were included. This study utilized two flavours of trident chewing gum (red and green) to measure masticatory efficiency. The child was asked to chew half a strip of red and green chewing gum placed one on top of the other using either the noncrown or crown side 15 times. Another set of chewing gum was given to the child to chew 20 times on the same side. The chewing exercise was repeated using teeth on the other side. Chewed gum samples were collected, photographed, and analysed via ImageJ software to determine the red and green areas. Masticatory efficiency was subsequently calculated with the help of a formula in which the red areas and green areas were calculated via ImageJ software. The data were analysed with paired t tests via SPSS (version 20.0). RESULTS: When the mean values of the crown side were compared with those of the noncrown side following 15 chewing cycles, the chewing efficiency on the noncrown side was greater, with a difference of 0.303, whereas the chewing efficiency following 20 chewing cycles was greater on the crown side, with a difference of 0.814. However, both differences were statistically nonsignificant, with t values of -0.07 and 0.26, respectively, and p values of 0.94 and 0.8, respectively. CONCLUSION: The presence of SSCs on the molars of children did not affect masticatory efficiency.

The functional role of the rabbit digastric muscle during mastication.

Muscle spindle abundance is highly variable in vertebrates, but the functional determinants of this variation are unclear. Recent work has shown that human leg muscles with the lowest abundance of muscle spindles primarily function to lengthen and absorb energy, while muscles with a greater spindle abundance perform active-stretch-shorten cycles with no net work, suggesting that muscle spindle abundance may be underpinned by muscle function. Compared with other mammalian muscles, the digastric muscle contains the lowest abundance of muscle spindles and, therefore, might be expected to generate substantial negative work. However, it is widely hypothesised that as a jaw-opener (anatomically) the digastric muscle would primarily function to depress the jaw, and consequently do positive work. Through a combination of X-ray reconstruction of moving morphology (XROMM), electromyography and fluoromicrometry, we characterised the 3D kinematics of the jaw and digastric muscle during feeding in rabbits. Subsequently, the work loop technique was used to simulate in vivo muscle behaviour in situ, enabling muscle force to be quantified in relation to muscle strain and hence determine the muscle's function during mastication. When functioning on either the working or balancing side, the digastric muscle generates a large amount of positive work during jaw opening, and a large amount of negative work during jaw closing, on average producing a relatively small amount of net negative work. Our data therefore further support the hypothesis that muscle spindle abundance is linked to muscle function; specifically, muscles that absorb a relatively large amount of negative work have a low spindle abundance.

Chewing Side Preference, Facial Asymmetry and Related Factors in the Northern Finland Birth Cohort 1986.

OBJECTIVE: The aim of this study was to find out how the preferred chewing side (PCS) affects facial asymmetry, what kind of factors affect PCS, and whether there are differences in facial asymmetry between symmetrical and asymmetrical masticators. MATERIAL AND METHODS: The study included 748 subjects (females n=452, males n=296) born in 1985-1986 in Northern Finland (Northern Finland Birth Cohort 1986, NFBC 1986). Subjects' faces were captured in facial 3D images with stereophotogrammetry technology, and they filled in a questionnaire concerning oral health. A comprehensive dental examination was done by a dentist. Subject´s chewing side preference was studied by chewing a piece of paraffin, cotton roll or parafilm. Asymmetry was measured from 3D images with different asymmetry measurements and facial landmarks. RESULTS: Reduced number of teeth on contralateral side affects PCS (OR = 2.44 in the case of one tooth is missing). Being female increased the whole face and lower face symmetry (p values <0.001-0.824). Self-reported TMD pain has an effect on the sidedness of the chin; there is more pain in the larger side of the chin (OR = 9.45). Different chewing materials had no significant effect on the proportion of chewing sides. CONCLUSIONS: Females have a more symmetrical face compared to males. PCS does not have a statistically significant effect on facial asymmetry, but the variable affecting PCS itself is extracted teeth.

Controlled and Real-Life Investigation of Optical Tracking Sensors in Smart Glasses for Monitoring Eating Behavior Using Deep Learning: Cross-Sectional Study.

BACKGROUND: The increasing prevalence of obesity necessitates innovative approaches to better understand this health crisis, particularly given its strong connection to chronic diseases such as diabetes, cancer, and cardiovascular conditions. Monitoring dietary behavior is crucial for designing effective interventions that help decrease obesity prevalence and promote healthy lifestyles. However, traditional dietary tracking methods are limited by participant burden and recall bias. Exploring microlevel eating activities, such as meal duration and chewing frequency, in addition to eating episodes, is crucial due to their substantial relation to obesity and disease risk. OBJECTIVE: The primary objective of the study was to develop an accurate and noninvasive system for automatically monitoring eating and chewing activities using sensor-equipped smart glasses. The system distinguishes chewing from other facial activities, such as speaking and teeth clenching. The secondary objective was to evaluate the system's performance on unseen test users using a combination of laboratory-controlled and real-life user studies. Unlike state-of-the-art studies that focus on detecting full eating episodes, our approach provides a more granular analysis by specifically detecting chewing segments within each eating episode. METHODS: The study uses OCO optical sensors embedded in smart glasses to monitor facial muscle activations related to eating and chewing activities. The sensors measure relative movements on the skin's surface in 2 dimensions (X and Y). Data from these sensors are analyzed using deep learning (DL) to distinguish chewing from other facial activities. To address the temporal dependence between chewing events in real life, we integrate a hidden Markov model as an additional component that analyzes the output from the DL model. RESULTS: Statistical tests of mean sensor activations revealed statistically significant differences across all 6 comparison pairs (P<.001) involving 2 sensors (cheeks and temple) and 3 facial activities (eating, clenching, and speaking). These results demonstrate the sensitivity of the sensor data. Furthermore, the convolutional long short-term memory model, which is a combination of convolutional and long short-term memory neural networks, emerged as the best-performing DL model for chewing detection. In controlled laboratory settings, the model achieved an F1-score of 0.91, demonstrating robust performance. In real-life scenarios, the system demonstrated high precision (0.95) and recall (0.82) for detecting eating segments. The chewing rates and the number of chews evaluated in the real-life study showed consistency with expected real-life eating behaviors. CONCLUSIONS: The study represents a substantial advancement in dietary monitoring and health technology. By providing a reliable and noninvasive method for tracking eating behavior, it has the potential to revolutionize how dietary data are collected and used. This could lead to more effective health interventions and a better understanding of the factors influencing eating habits and their health implications.

The Influence of the Type of Breathing on the Masticatory Muscle Patterns in Children.

Background and Objectives: The aim was to compare the activity of the masseter muscles in children with different types of breathing. Materials and Methods: A cross-sectional study was conducted including patients aged 6-12 years with mixed dentition, who came for oral care at the Master's Degree in Pediatric Dentistry program at the Complutense University of Madrid (UCM), according to inclusion and exclusion criteria. The sample was divided into three groups: nasal breathers without dental alterations (control group), oral breathers with dental malocclusion, and oral breathers with previous orthodontic treatment. An electromyography was performed, and statistic methods were conducted with a 95% confidence to contrast hypothesis. Results: A total of 122 children were analyzed and distributed into three groups. The electrical muscle activity of masseters was significantly different between the study groups (p < 0.001 for all comparisons). Pairwise comparisons revealed a significantly higher electrical muscle activity in the control group (nasal breathers) during chewing compared to both groups of oral breathers (p < 0.001 for both comparisons). Orthodontic treatment decreased electrical muscle activity during isometric contraction in oral breathers compared to nasal breathers (p < 0.001), but did not significantly affect electrical muscle activity during chewing. Higher decompensation values were obtained in oral breathers without previous orthodontic treatment compared the other study groups (p < 0.001 for both comparisons), although electrical muscle activity values were similar in both groups of oral breathers (p > 0.05 for both comparisons). Conclusions: Differences in electrical muscle activity between nasal and oral breathers can be confirmed. Oral breathers with and without orthodontic treatment showed lower electrical muscle activity of masseters during chewing than nasal breathers, while at isometric contraction, only oral breathers with previous orthodontic treatment showed lower electrical activity. Higher decompensation values were found in oral breathers without previous orthodontic treatment, in comparison to the control group and oral breathers with previous orthodontic treatment.

Masticatory simulators based on oral physiology in food research: A systematic review.

A masticatory simulator is a mechanical device that mimics the physiological structures of the human oral cavity, chewing movement system, and functions. The advantage of this device lies in real-time tracking and analysis of food boluses within a sealed oral space, offering a direct validation platform for food experiments without constraints related to time, space, and individual variations. The degree to which the masticatory simulator simulates physiological structures reflects its efficacy in replicating oral physiological processes. This review mainly discusses the physiological structures of the oral cavity, the simulation of biomimetic components, and the development, feasibility assessment, applications, and prospects of masticatory simulators in food. The highlight of this review is the analogy of biomimetic component designs in masticatory simulators over the past 15 years. It summarizes the limitations of masticatory simulators and their biomimetic components, proposing potential directions for future development. The purpose of this review is to assist readers in understanding the research progress and latest literature findings on masticatory simulators while also offering insights into the design and innovation of masticatory simulators.

A Comparison of Oral Function in Older In- and Outpatients: An Observational Study.

(1) Background: Insufficient data exist regarding oral function among older adults in Europe. Therefore, we aimed to assess and compare oral function between older in- and outpatients and identify predictors of low masticatory performance. (2) Methods: Patients were consecutively recruited from the outpatient center (n = 31) and the inpatient geriatric department (n = 31) at a tertiary University Hospital in Switzerland in 2023. Assessments on oral function included the total number of intraoral eruptive teeth, number of supporting zones with dentures, maximal bite force (Dental Prescale II, Fuji Film Corp., Tokyo, Japan), and masticatory performance (Hue-Check Gum©, University of Bern, Bern, Switzerland) using a visual (SA1-SA5) and a digital (SD_Hue) scale. The visual and digital assessment of masticatory performance showed a strong correlation (Kendall tau = 0.83). Low masticatory performance was defined as SA-Grade 1-2 (vs. SA3-SA5 as reference). In a multivariate model adjusting for age, sex, and clinical setting, we investigated associations of maximal bite force, few eruptive teeth, and few supporting zones with low masticatory performance. (3) Results: Mean age was 81.9 (standard deviation (sd) 5.2) years, and 62.9% were female. Overall, maximal bite force was 247 N (sd 261). A total of 39 patients (63.9%) had a low masticatory performance, 62.9% a low maximal bite force, and 50% a low number of eruptive teeth (<10). Masticatory performance, number of eruptive teeth, and maximal bite force did not significantly differ between in- and outpatients. The number of supporting zones was significantly higher in outpatients compared to inpatients (median 4, interquartile range (IQR) 4-4; vs. 4, IQR 2-4; p = 0.03). In the multivariate model, maximal bite force and a low number of eruptive teeth were independently associated with low masticatory performance (adjusted odds ratio 7.4 (95% CI, 1.8-30.4; p < 0.01), and OR 7.8 (95% CI, 1.7-36.4; p < 0.01), respectively). (4) Conclusions: Impaired oral function is highly prevalent in both European older in- and outpatients to a similar degree. The association of low masticatory performance with maximal bite force and with a low number of eruptive teeth may indicate that a basic screening should include either of these parameters to identify impaired oral function.

Accuracy of the surgical execution of virtually planned deep circumflex iliac artery flaps and their appropriateness for masticatory rehabilitation.

BACKGROUND: Tumorous diseases of the jaw demand effective treatments, often involving continuity resection of the jaw. Reconstruction via microvascular bone flaps, like deep circumflex iliac artery flaps (DCIA), is standard. Computer aided planning (CAD) enhances accuracy in reconstruction using patient-specific CT images to create three-dimensional (3D) models. Data on the accuracy of CAD-planned DCIA flaps is scarce. Moreover, the data on accuracy should be combined with data on the exact positioning of the implants for well-fitting dental prosthetics. This study focuses on CAD-planned DCIA flaps accuracy and proper positioning for prosthetic rehabilitation. METHODS: Patients post-mandible resection with CAD-planned DCIA flap reconstruction were evaluated. Postoperative radiograph-derived 3D models were aligned with 3D models from the CAD plans for osteotomy position, angle, and flap volume comparison. To evaluate the DCIA flap's suitability for prosthetic dental rehabilitation, a plane was created in the support zone and crestal in the middle of the DCIA flap. The lower jaw was rotated to close the mouth and the distance between the two planes was measured. RESULTS: 20 patients (12 males, 8 females) were included. Mean defect size was 73.28 ± 4.87 mm; 11 L defects, 9 LC defects. Planned vs. actual DCIA transplant volume difference was 3.814 ± 3.856 cm³ (p = 0.2223). The deviation from the planned angle was significantly larger at the dorsal osteotomy than at the ventral (p = 0.035). Linear differences between the planned DCIA transplant and the actual DCIA transplant were 1.294 ± 1.197 mm for the ventral osteotomy and 2.680 ± 3.449 mm for the dorsal (p = 0.1078). The difference between the dental axis and the middle of the DCIA transplant ranged from 0.2 mm to 14.8 mm. The mean lateral difference was 2.695 ± 3.667 mm in the region of the first premolar. CONCLUSION: The CAD-planned DCIA flap is a solution for reconstructing the mandible. CAD planning results in an accurate reconstruction enabling dental implant placement and dental prosthetics.

Effectiveness of orofacial myofunctional intervention to mitigate facial aging signs: a clinical trial. / Efetividade da intervenção miofuncional orofacial para atenuar sinais do envelhecimento facial: ensaio clínico.

PURPOSE: Propose and verify the efficiency of myofunctional intervention program to attenuate facial aging signs and balance the orofacial functions. METHODS: Thirty women, aged 50 to 60 years, randomly divided into: therapy group (TG) submitted to Orofacial Myofunctional Therapy and electromyographic biofeedback group (EBG), submitted to the same program associated with electromyographic biofeedback for chewing, swallowing, and smiling functions training. Aesthetic and oromyofunctional aspects were assessed from photographs, videos, MBGR Protocol and scales for assessing facial aging signs, described in the literature. 50-minute sessions were held weekly for nine weeks and monthly for six months after washout period. Three assessments, identical to the initial one, were performed in the tenth week, eighth week after washout and conclusion of the research. The participants responded to the Satisfaction Questionnaire on the tenth week. RESULTS: The statistical analysis using the ANOVA, Tukey and Mann Whitney tests, for inter and intragroup comparison, showed that: intervention promoted attenuation of facial aging signs mainly in TG group, balance of chewing and swallowing functions in both groups; there was an impact of electromyographic biofeedback on the degree of participants' satisfaction, greater for EBG; interruption of the program for eight weeks resulted in aesthetic losses, mainly in TG, yet not functional losses, in both groups; the six monthly sessions had a limited impact on overcoming the esthetic losses that occurred after washout. CONCLUSION: The proposed program resulted in attenuation of aging signs, mainly in the TG group and improvement in orofacial functions, in both groups.

OBJETIVO: Propor e verificar a eficiência de um programa de intervenção miofuncional para atenuar sinais do envelhecimento facial e equilibrar as funções orofaciais. MÉTODO: 30 mulheres, entre 50 e 60 anos, divididas aleatoriamente em: grupo terapia (GT), submetido ao programa de terapia miofuncional orofacial e grupo biofeedback eletromiográfico (GBE), submetido ao mesmo programa associado ao biofeedback eletromiográfico para treinamento da mastigação, deglutição e sorriso. Aspectos estéticos e oromiofuncionais foram avaliados a partir da documentação das fotografias e vídeos, do Protocolo de avaliação miofuncional orofacial MBGR e escalas de avaliação dos sinais de envelhecimento facial descritas na literatura. Sessões de 50 minutos foram realizadas semanalmente, durante nove semanas e mensalmente, durante seis meses, após washout. Três avaliações, idênticas à inicial, foram realizadas na décima semana, oitava semana após washout e conclusão da pesquisa. As participantes responderam ao Questionário de Satisfação na décima semana. RESULTADOS: A análise estatística realizada, por meio dos testes ANOVA, Tukey e Mann Whitney, para comparação inter e intragrupos, demonstrou que: houve atenuação dos sinais do envelhecimento facial, principalmente no GT e equilíbrio das funções mastigação e deglutição nos dois grupos; houve impacto do biofeedback eletromiográfico sobre o grau de satisfação das participantes, sendo maior no GBE; a interrupção do programa durante oito semanas resultou em perdas estéticas, principalmente no GT, mas não em perdas funcionais, nos dois grupos; as seis sessões realizadas mensalmente tiveram impacto limitado para superação das perdas estéticas ocorridas após washout. CONCLUSÃO: O programa proposto resultou em atenuação dos sinais de envelhecimento, principalmente no grupo GT e melhoria nas funções orofaciais, nos dois grupos.

Tissue surface adaptation and retention of digital obturator after one year of use.

BACKGROUND: Effect of aging on tissue adaptability and retention of digital obturator is still under investigation. METHODS: A maxillary Armany (class I) epoxy reference model was scanned to fabricate digital obturator fabricated from milled Co-Cr framework and 3D printed bulb. A color map of the scanned reference and digital obturator was made using Geomagic software to evaluate the accuracy of fit before and after cyclic loading using ROBOTA chewing simulator at 37,500, 75,000 and 150,000 cycles to simulate clinically 3-, 6- and 12-months chewing condition. Insertion-removal condition simulating the placement and removal of the obturator was done using repeated 360, 720 and 1440 cycles and retention was evaluated before and after the repeated cycles. Data were collected, tabulated and statistically analyzed using Statistical Package for Social Sciences (IBM SPSS Statistics 26). Student t-test and multi variable ANOVA test were used to detect significance. P-value < 0.05 was considered significant difference. RESULTS: For retention test: There was a significant difference between baseline and 3, 6 and12 months. For the tissue surface adaptation test: There was significant difference at all measured areas (P-value < 0.05) before and after application of load. CONCLUSION: digitally designed and fabricated obturator was highly retentive and has excellent tissue surface adaptation upon fabrication, After application of load; reduction of retention and lack of tissue adaptation were resulted. THE CLINICAL IMPLICATION: of this manuscript is that digital obturator can be used successfully with the shortcomings of loosening retention and adaptation afterwhile. So, clinical trials should investigate the clinical acceptance of these shortcomings.

Correlation between GLCM-based texture features of the lateral pterygoid muscle and cognitive function in patients with idiopathic normal pressure hydrocephalus: a preliminary report.

PURPOSE: The potential relationship between mastication ability and cognitive function in idiopathic normal pressure hydrocephalus (iNPH) patients is unclear. This report investigated the association between mastication and cognitive function in iNPH patients using the gray level of the co-occurrence matrix on the lateral pterygoid muscle. METHODS: We analyzed data from 96 unoperated iNPH patients who underwent magnetic resonance imaging (MRI) between December 2016 and February 2023. Radiomic features were extracted from T2 MRI scans of the lateral pterygoid muscle, and muscle texture parameters were correlated with the iNPH grading scale. Subgroup analysis compared the texture parameters of patients with normal cognitive function with those of patients with cognitive impairment. RESULTS: The mini-mental state examination score correlated positively with the angular second moment (P < 0.05) and negatively with entropy (P < 0.05). The dementia scale (Eide's classification) correlated negatively with gray values (P < 0.05). Gray values were higher in the cognitive impairment group (64.7 ± 16.6) when compared with the non-cognitive impairment group (57.4 ± 13.3) (P = 0.005). Entropy was higher in the cognitive impairment group (8.2 ± 0.3) than in the non-cognitive impairment group (8.0 ± 0.3) (P < 0.001). The area under the receiver operating characteristic curve was 0.681 (P = 0.003) and 0.701 (P < 0.001) for gray value and entropy, respectively. CONCLUSION: Our findings suggest an association between heterogeneity of mastication and impaired cognitive function in iNPH patients and highlight muscle texture analysis as a potential tool for predicting cognitive impairment in these patients.

Chewing shrews: Examining the morphology and function of the masticatory musculature in Soricidae via diffusible iodine-based contrast-enhanced computed tomography.

Essential for sustaining a high metabolic rate is the efficient fragmentation of food, which is determined by molar morphology and the movement of the jaw. The latter is related to the jaw morphology and the arrangement of the masticatory muscles. Soricid jaw apparatuses are unique among mammals, as the articulation facet on the condylar process is separated into a dorsal and a ventral part, which has often been linked to more differentiated jaw motions. Soricidae also possess a remarkably elongated angular process. However, the precise function of the unique morphology of soricid jaw apparatuses has not been fully understood yet. By digitally reconstructing the masticatory musculature via the diffusible iodine-based contrast-enhanced computed tomography technique, we show how the unique jaw morphology is reflected in the spatial organization as well as the inner architecture and respective fascicle orientations of the muscles. From the lines of action of the m. masseter and the m. pterygoideus internus, both muscles inserting on the lateral and medial side of the angular process, respectively, we infer that the angular process is substantial for roll and yaw rotations of the mandible. The m. masseter is subdivided into four and the m. pterygoideus internus into five subunits, each exhibiting a slightly different line of action and torque. This enables Soricidae to adjust and adapt these rotational movements according to the properties of the ingested food, allowing for more efficient fragmentation. Additionally, those guided rotational motions allow for precise occlusion despite tooth wear. The temporalis is the largest of the adductor muscles and is mainly responsible for exerting the bite force. Overall, the unique jaw bone morphology in conjunction with the complex muscle arrangement may contribute towards a more efficient energy gain and the maintenance of a high metabolic rate, which is crucial for small-bodied mammals such as shrews.

Modelling of dynamic mastication physics of cheese/casein gels as function of milk-fat distribution and intensity of thermo-mechanical treatment.

Pasta filata-style cheese products are among the world's most famous cheese varieties. Thermo-mechanical processing of cheese curd results in stringy, fibrous, and anisotropic structures with pleasing texture attributes. A recent area of research focuses on improving yield during the manufacturing of pasta filata-type cheese products by homogenizing the milk. This process reduces the size of fat droplets, leading to better retention of milk fat during curd plasticization. As this sometimes results in texture deficits, this study aims to investigate the impact of thermo-mechanical processing on curd from homogenized and non-homogenized milk. The hypothesis is that increased thermo-mechanical processing, leading to more anisotropic structural elements, may offset texture deficits caused by homogenization. To assess textural and structural changes due to homogenization and thermo-mechanical processing, mechanical tests including rheology and texture analysis were conducted, along with confocal-laser-scanning microscopy. Additionally, sensory evaluation involving panelists consuming the samples and recording mastication properties such as muscle activity and jaw movement was carried out. Dynamic data modeling was used to derive connections between structure and texture. Results showed that homogenization alone did not yield significant differences between the samples, but plasticization and texturization properties differed significantly. Non-homogenized samples developed a distinct fibrous structure, and muscle activities and jaw movements increased significantly (p < 0.01) with longer thermo-mechanical processing.

Ontogeny of the masticatory muscles in the opossum Didelphis albiventris (Marsupialia, Didelphimorphia, Didelphidae).

Opossums (marsupials of the Didelphidae family) retain a generalized masticatory apparatus and tribosphenic molars, often used as models to understand the evolution of mastication in early therian mammals. Like all marsupials, their growth goes through a stage when pups complete their development while permanently attached to the mother's teats before weaning and starting feeding on their own. Yet, while the masticatory muscles of adults are known, as is the ontogeny of the cranium and mandible, the ontogenetic changes in the masticatory muscles remain unknown. Here we describe for the first time the changes in the masticatory muscles observed in lactating pups, and weaned juveniles, subadults, and adults in the White-eared opossum, Didelphis albiventris, through dissection of 25 specimens and quantification of relative muscle masses, lines of actions and mechanical advantages whenever possible. We also assessed the scaling patterns of muscle masses and mechanical advantages through ontogeny. The main changes, as expected, were found between suckling and weaned specimens, although some changes still occurred from juveniles to adults. The adult adductor musculature is similar to the other Didelphis species already known, with a dominant m. temporalis that originates on the lateral wall of the skull, up to the sagittal and nuchal crests, and fills the zygomatic arch when inserting into the lateral and medial surfaces of the coronoid process, respectively through the pars superficialis and pars profunda. The m. masseter is also subdivided in superficial and deep bundles which originate posteriorly in the maxilla and zygomatic arch, and insert into the angular process and masseteric fossa in the mandible. The m. pterygoideus medialis originates from the palatine, the pterygoid bone and the alisphenoid, and it inserts on the angular process medially. Suckling pups showed muscles with more restricted attachments, reduced muscle lines of action, and less diversity in the fiber orientation. The absence of the postorbital constriction also resulted in a distinct morphology of the m. temporalis pars profunda, through two bundles, one anterior and one posterior, which insert more inferiorly into the mandible. These major changes can be related to the onset of mastication and to size-related changes in growing weaned age classes. In general, all adductor muscles grew with positive allometry, and increased their fixation areas through, in part, the development of specific regions of the cranium and mandible. Their lines of action also increase and diversify along ontogeny. These changes can be related to the functional requirements for fixation during lactation, which shift to adduction and mastication movements after weaning.

Assessment of masticatory performance in pediatric patients receiving preformed crowns by Hall technique: a controlled clinical trial.

PURPOSE: The purpose of the study was to assess and compare the masticatory performance in children receiving preformed metal crown by Hall technique and conventional technique. METHODS: Children having teeth indicated for restorative/endodontic therapy and belonging to the age group of six to ten years were invited to participate in the study. Eighteen children received preformed metal crowns (PMCs) by Hall technique. Meanwhile, nineteen children received preformed metal crowns by the conventional technique. Their masticatory performance (MP) was assessed at T0 (pre-intervention), T1 (day 1 post-intervention), T2 (1 week), T3 (2 weeks), T4 (1 month) and T5 (3 months) using Hue-check Gum® (University of Bern, Switzerland). The chewing gum samples were scanned within 24 h of their collection and processed in the ViewGum Software©. The software calculated the hue value (VOH) which indicated the masticatory performance of the individual. A questionnaire was given to the parents at T4 and T5 to assess any discomfort or pain associated with PMCs placed in both groups. RESULTS: The evaluation of masticatory performance using the two-color chewing method revealed reduction in MP on day 1 post-intervention (p < 0.001) for both groups. However, the MP values recorded at T5 were comparable to the baseline values at T0 (p = 0.009). No significant discomfort or pain was reported in both groups. CONCLUSION: The findings of the current clinical study indicate that placement of PMCs by both conventional and Hall technique in children deteriorates their MP which equilibrates within 1 month. CLINICAL TRIAL REGISTRY OF INDIA NUMBER: CTRI/2021/02/031532 [Registered on: 25/02/2021]-Trial Registered Prospectively.

Edible Bite Force Sensor: A Novel Approach to Measuring Bite Force in Biomedical and Dental Applications.

BACKGROUND Measurement of bite force plays a crucial role in assessment of the masticatory system. With a growing interest in detecting occlusal irregularities, bite force sensors have garnered attention in the biomedical field. This study aimed to introduce a hydrogel bite force sensor, based on hydroxyethyl-cellulose-fructose-water (HEC-F-water), for premolar and molar teeth, and to evaluate it using optical profilometry, infrared spectroscopy (FTIR), and Instron Tension testing system, with 2.5 cm (1 inch) margins at top, bottom, right, and left. MATERIAL AND METHODS We fabricated 20 HEC-F-water hydrogel samples sized with surface of 1×1 cm, with 2 different widths - 1 mm and 5 mm. The samples were characterized using optical profilometry and FTIR and their electrical characteristics were determined using an impedance analyzer. Aluminum (Al) electrodes, fabricated using Cutting Plotter, were used to form a HEC-F-water-based transducer, which was used for bite force sensing. The Instron tensile testing system was employed, utilizing 3D printed models of the upper and lower jaw, to simulate biting. Forces in the range between 40 N and 540 N were exerted upon the transducer, and the output change in the electrical signal was measured. RESULTS The study determined the transfer function between bite force and capacitance. The fabricated sensor exhibited a sensitivity of 3.98 pF/N, an input range of 500 N, output range of 2 nF, and accuracy of 95.9%. CONCLUSIONS This study introduces an edible bite force sensor employing an edible hydrogel as a dielectric, presenting a novel avenue in the development of edible sensorics in dentistry.

Predictive modelling of freeway space utilising clinical history, normalised muscle activity, dental occlusion, and mandibular movement analysis.

This study aimed to predict dental freeway space by examining the clinical history, habits, occlusal parameters, mandibular hard tissue movement, soft tissue motion, muscle activity, and temporomandibular joint function of 66 participants. Data collection involved video-based facial landmark tracking, mandibular electrognathography, surface electromyography of mandibular range of motion, freeway space, chewing tasks, phonetic expressions, joint vibration analysis, and 3D jaw scans of occlusion. This resulted in a dataset of 121 predictor features, with freeway space as the target variable. Six models were trained on synthetic data ranging from 500 to 25,000 observations, with 65 original observations reserved for testing: Linear Regression, Random Forest, CatBoost Regressor, XGBoost Regressor, Multilayer Perceptron Neural Network (MPNN), and TabNet. Explainable AI indicated that key predictors of freeway space included phonetics, resting temporalis muscle activity, mandibular muscle activity during clenching, body weight, mandibular hard tissue lateral displacements, and dental arch parameters. CatBoost excelled with a test error of 0.65 mm using 5000 synthetic data points, while a refined MPNN achieved the best performance with 25,000 synthetic data points and 121 unique predictors, yielding an absolute error of 0.43 mm on the 65 original observations.

Comparison of perceived masticatory ability in completely edentulous patients treated with thermoplastic complete denture versus single implant-retained mandibular overdenture: a single-center prospective observational study.

Background: 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. Methods: 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. Results: 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. Discussion: The study's findings indicate that using immediate loading single implant-retained mandibular overdentures significantly improved PrMA in completely edentulous patients.

Oral behaviors and anxiety are significant predictors of jaw function limitation in patients with anterior disc displacement without reduction.

OBJECTIVE: We aimed to describe jaw function characteristics in patients with anterior disc displacement without reduction (ADDWoR) using the jaw function limitation scale (JFLS), and to investigate the effects of biopsychosocial risk factors on limited jaw function. DESIGN: In this cross-sectional study of 636 patients with ADDWoR (females, 568; males, 68), we used the JFLS to assess jaw function. Behavioral, psychological, sociodemographic, and biomedical data were collected. Multivariate logistic regression analysis was used to determine risk factors affecting limited jaw function. A receiver operating characteristic curve was used to evaluate the predictive effect of these risk factors. RESULTS: ADDWoR-associated limitations included restricted jaw mobility and mastication, which exceeded median global functional limitations scale scores, especially mouth opening to bite an apple and chewing tough food. Females had greater limitations in jaw mobility, verbal and emotional communication, and overall. Multivariate logistic regression analysis findings indicated that oral behaviors, anxiety, sex, pain intensity, and maximal mouth opening (MMO) were predictive of limited jaw function (area under the curve, 72 %). CONCLUSION: Patients with ADDWoR reported mastication and jaw mobility restrictions, with females having more pronounced limitations, and specific risk factors identified as significant predictors of jaw function limitations. Along with pain relief and improvement in MMO, appropriate psychological counseling and oral behavioral correction facilitates recovery of jaw function in such patients.

Craniosynostosis: orofacial and oral health perspectives with masticatory insights.

BACKGROUND: Craniosynostosis (CS), premature fusion of one or more cranial sutures, leads to abnormal skull development, impacting both facial esthetics and oral function. This study aimed to evaluate the specific orofacial and oral health characteristics, including masticatory performance, in Thai patients with CS. METHODS: A comparative study was conducted with Thai CS patients aged 6-17 years and a control group of healthy individuals with similar age distribution. Assessments included craniofacial morphology, oral health status, and masticatory performance. Intergroup comparisons utilized appropriate statistical tests. RESULTS: The study included 24 CS patients with a mean age of 10.11 ± 2.98 years and 30 controls. CS patients exhibited a significantly higher prevalence of various oral conditions compared to controls: cleft palate (20.8%), anterior open bite (41.7%), anterior crossbite (54.2%), posterior crossbite (50%), combined anterior-posterior crossbite (45.8%), dental crowding in both maxilla and mandible (50% and 45.8% respectively), congenitally missing teeth (50%), supernumerary teeth (12.5%), and eruption failure (54.2%). Furthermore, CS patients exhibited significantly higher caries prevalence and susceptibility, alongside poorer oral hygiene, compared to controls. Regarding jaw relationships, CS patients exhibited a significantly higher proportion of Angle's Class III malocclusion (50%) compared to the control group, where Class I malocclusion was predominant (50%). Masticatory performance, assessed using the two-color gum mixing ability test, showed significantly higher hue variance in CS patients (0.12 ± 0.07) compared to the control group, indicating reduced chewing performance. CONCLUSION: This study underscores the significant orofacial and oral health challenges faced by children with CS, including a high prevalence of malocclusions, dental anomalies, elevated caries experience, and compromised masticatory function. These findings emphasize the importance of tailored interventions and comprehensive oral healthcare strategies to address the unique needs of this population and improve their overall quality of life.