Masticatory Adaptation to Occlusal Changes

Age-Specific Clinical and Brain Features of Masticatory and Swallowing Performance

BACKGROUND

Mastication and swallowing are the fundamental processes for food intake and the primary functions of living. The clinical and neurological features associated with individual differences in masticatory performance and swallowing performance have remained unexplored.

OBJECTIVES

The study focuses on the age-specific association between masticatory/swallowing performance and oral/systemic/nutritional factors and their association with functional brain connectivity.

METHODS

One-hundred and eighteen healthy adults (48 older age, 27 middle-aged and 43 younger age) were recruited for food-mixing and repetitive saliva swallowing tests, respectively, indexed for masticatory and swallowing performance, as well as oral, systemic and nutritional factors, including mid-upper arm and calf circumferences. Structural and resting-state (rs) functional magnetic resonance imaging was acquired. Seed-based connectivity analyses were conducted to investigate the association between swallowing performance and rs-functional connectivity (rs-FC) of the sensorimotor network.

RESULTS

(a) In contrast to mastication, individual swallowing performance was not associated with oral or systemic factors. (b) In older adults, higher mid-upper arm and calf circumferences were associated with both higher masticatory and swallowing performance (a statistically significant interaction, p = 0.018). (c) In older adults, higher swallowing performance was associated with stronger rs-FC between the cerebellum and basal ganglia (p = 0.008, corrected for small volume), whilst higher masticatory performance was associated with stronger rs-FC between the cerebellum and primary sensorimotor cortices (p = 0.045, corrected for small volume).

CONCLUSION

Our findings reveal age-specific associations between swallowing, mastication, nutritional factors and brain functional connectivity. The findings highlight the association between the brain and individual differences in masticatory and swallowing performance.

Effect of adenoid hypertrophy and adenoidectomy on bite force in children: Twelve month follow-up, case-control study

OBJECTIVE

The effects of adenoid hypertrophy (AH) and adenoidectomy on maximal bite force (MBF) in patients were evaluated by comparing them with healthy controls.

METHODS

A total of 118 children diagnosed with AH and undergoing adenoidectomy (Group A), and healthy controls (Group B) were included. The MBF and nasopharyngeal airway passage distance (NAPD) were recorded.

RESULTS

There was a correlation between NAPD and MBF at the beginning of the study (r = -0.675 and p < 0.001). The initial mean MBF of Groups A and B were 318.37 ± 70.76 N and 344.04 ± 64.14 N, respectively (p = 0.041). However, there was no significant difference between the groups due to the increase in the MBF of Group A at 12 months (p = 0.165).

CONCLUSION

The MBF may be negatively affected in proportion to decreased NAPD, and it could also be an indicator for monitoring the status of children with AH.

Alteration of Mastication Force via Intraoral Closed-loop Electrical Stimulation

Mastication plays an important role in effective food digestion and nutrient absorption. Therefore, regulating masticatory force in people with declining mastication function is significant for maintaining health and quality of life. In this study, we tested the effect of tactile augmentation on mastication force. To augment tactile feedback during mastication, we applied closed-loop electrical stimulation onto the mandibular vestibule using an intraoral tooth-borne electronic system. We hypothesized that closed-loop electrical stimulation, timed with mastication and applied to the nerves delivering tactile feedback to the brain, would evoke an increase in masticatory force. Experiments were completed using the intraoral system with six healthy human subjects who masticated soft and hard foods with and without stimulation during the experiment. Their mastication forces were recorded ten times per condition. The recorded mastication force profile showed that mastication force was higher with the harder food. Also, mastication force increased when electrical stimulation was applied, compared to the non-stimulated condition. These results support the hypothesis that tactile augmentation by intraoral closed-loop electrical stimulation will increase masticatory force. Other mastication parameters including period, spike width, and duty cycle are also changed by electrical stimulation. Further, stimulation left a strong aftereffect on these mastication parameters.

Over-provisionals - Simplified chairside preoperative evaluation of esthetic and functional changes during full mouth rehabilitation

Prosthetic rehabilitation in multifaceted dental abnormality needs sequential planning to ensure adaptation of oral and associated musculature. Reduction of tooth structure before adaptation of oral and associated components may complicate the treatment modality if compliance of the musculature is poor. Hence, the fabrication of over-provisional in esthetic rehabilitation enables to assess of the success of the treatment plan preoperatively before invasive trials. A 55-year-old male with a diagnosis of Category I loss of vertical dimension, according to Turner and Missirlian classification, required full mouth rehabilitation. The case report depicts the preoperative management of full mouth rehabilitation with direct chair-side technique using over-provisional to analyze the esthetic and functional changes. Restoration of esthetics is a complex task that needs patient satisfaction to achieve success. Over-provisional is a simplified method of establishing esthetics and functional rehabilitation. Esthetic and functional rehabilitation of an individual can be an easy transition when preoperative evaluation of the final prosthesis design is visually created intraorally.

Investigating the Influence of a Tooth Absence on Facial Bone Growth Using a Porcine Model

With the current state of knowledge regarding disorders of facial bone development, including anodontia, the development of a suitable animal model for preclinical studies is essential. The agenesis of dental buds occurs in about 25% of the human population. Prospects for treatment include the use of growth factors, stem cells, and bioengineering. This study aimed to investigate the influence of a tooth absence on facial bone growth, develop a technique for the application of growth factors to the developing bone, and analyze the comparative effect of the application of selected active proteins on the growth of the maxilla and mandible. Piglets underwent germectomy, followed by computed tomography and X-ray; morphometric and histological analyses of the bones were performed, blood bone morphogenetic protein 2 and platelet-derived growth factor concentrations were determined, and the transcriptomic profile of the dentate ligament was analyzed using DNA microarrays. It was not possible to identify the most effective growth factor application algorithm for achieving normal jaw development. Normal mandibular bone structure and oral mucosa structure were observed in the germectomy groups with growth factor augmentation. The average height of the mandibular alveolar part in the area of the removed dental buds was significantly lower compared with that of the inoperable side, 3 months after surgery. However, no significant differences were found in the serum concentrations of BMP-2 and PDGF between groups. The animal model of bone development disorders (including anodontia) developed in the current study and the scheme for evaluating the efficacy and safety of the application of replacement therapy for craniofacial malformations are important in the development of the discipline and represent an important contribution to the introduction of treatment methods.

Assessment Tools for Masticatory Function in Periodontitis Patients: A Scoping Review

AIMS

The aim of this scoping review was to map the available evidence on assessment tools for masticatory function for periodontitis patients. It also aimed to examine the methodology of masticatory function assessment and to identify the elements of subjective masticatory function evaluation for periodontitis patients reported in the literature.

METHODS

A scoping review was conducted following the methodological guidance for the conduct of scoping reviews. Embase, MEDLINE, Web of Science, and Scopus were systematically searched for published studies in English reporting objective or subjective masticatory function assessment in periodontitis patients.

RESULTS

Forty-five studies were included in the analysis. The identified assessment tools for masticatory function were summarized using the terminology described by the recent consensus. Heterogeneity was observed in the approach of assessment, the type(s) and design of assessment tools, and the methods of measurement employed. Most studies utilized only one assessment tool. Seven studies reported composite objective assessment and five studies utilized assessment tools for both objective and subjective masticatory function. Items from the included instruments for subjective masticatory function were analyzed and categorized into seven potentially clinically relevant elements of subjective masticatory function evaluation. Unclear reporting on validation status was found in all included instruments for subjective masticatory function.

CONCLUSION

Variable methodologies have been reported to assess masticatory function in periodontitis patients. Future research is needed to discern the clinical utility of these assessment tools for masticatory function in periodontitis patients.

Can Different Impression Techniques Affect the Chewing Efficiency of Mandibular Implant-Retained Overdentures?

Several impression techniques and theories have been developed for implant-retained overdentures, each with its own set of advantages and limitations. This study aimed to assess the chewing efficiency of mandibular implant-retained overdentures fabricated using three distinct impression techniques (mucofunctional, selective, and minimal pressure impression techniques). Twenty-six patients with complete edentulism free from any oral or systemic disease were selected to participate in the study. Three complete mandibular implant-retained overdentures were constructed for each patient, and grouped into three groups according to the impression technique employed in overdenture construction; Group A: Patients were treated by mandibular implant-retained overdenture fabricated using mucofunctional impression technique; Group B: Patients were treated by mandibular implant-retained overdenture fabricated using selective pressure impression technique; Group C: Patients were treated by mandibular implant-retained overdenture fabricated using minimal pressure impression technique. Chewing efficiency was evaluated for each patient with the implant-retained mandibular overdenture after three months of prosthesis insertion as an adaptation period. The data were collected, tabulated, and statistically analyzed. Results indicated that mandibular implant-retained overdentures made using the mucofunctional impression technique showed higher mean values of chewing efficiency parameters than mandibular overdentures made using selective and minimal pressure impression techniques. Within the limitations of this study, it can be concluded that the mucofunctional impression technique may be effective in improving the chewing efficiency of mandibular implant-retained overdentures more than minimal or selective pressure impression techniques.

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.

Influence of restricted mastication on swallowing function

BACKGROUND

Oral food processing is an important part of daily food intake. A major part of this process is mastication, which prepares a bolus of food for swallowing by mechanically crushing and grinding ingested food between the teeth using rhythmic movements. Masticatory dysfunction is common in the elderly and in some neurological disorders and can have serious negative health consequences.

OBJECTIVE

This study investigated the effect of restricted mastication, achieved by experimentally reducing the duration of mastication, on masticatory patterns and subsequent swallowing function.

METHODS

Thirty healthy men (25 ± 3 years old) were instructed to chew gum jelly with a free mastication duration (G100), a half and a quarter duration of G100. Masseter and digastric electromyographic (EMG) activity was recorded to assess mastication and swallowing activity, respectively. In addition, the acceleration of the thyroid cartilage ridge was measured with an accelerometer. The root mean square (RMS) of muscle EMG activity in the masseter and digastric muscles, the number of masseter EMG bursts, time to peak and total duration of each masseter EMG burst, swallowing duration and laryngeal elevation latency were analysed.

RESULTS

Restricting masticatory duration reduced the number of mastication cycles (p < .001), prolonged the time to peak (p < .001) and total duration of masseter EMG bursts (p < .001) and resulted in an overall increased RMS score of masseter muscle activity (p = .017). Furthermore, restricted masticatory duration led to a decrease in both swallowing duration (p = .001) and laryngeal elevation latency (p = .012), with a significant increase in the RMS score of digastric muscle activity (p < .001).

CONCLUSIONS

Under the experimental conditions of restricted mastication, several adaptation features were observed, including changes in masticatory cycle characteristics and swallowing duration. Thus, although the overall masticatory efficiency was reduced, these adaptations allowed healthy individuals to still swallow safely.

A Literature Review of Vertical Dimension in Prosthodontics Theory and Practice - Part 1: Theoretical Foundations

Vertical dimension (VD) is a critical factor in prosthodontics, playing a pivotal role in the functional and aesthetic outcomes of dental treatments. This literature review explores theoretical foundations and the various aspects of VD, including its definition, measurement, and clinical significance in prosthodontics. The relationship between VD and temporomandibular disorders (TMDs) is examined. Additionally, the impact of VD on facial proportions and aesthetics is significant, as it affects the lower third of the face and influences the patient's overall appearance and self-esteem. In conclusion, understanding the intricate relationship between VD, TMDs, facial aesthetics, and psychological well-being is essential for effective prosthodontic treatment. This comprehensive review provides valuable insights into the multifaceted role of VD in enhancing both functional and aesthetic outcomes, ultimately improving patient satisfaction and quality of life.

To what extent can mastication functionality be restored following mandibular reconstruction surgery? A computer modeling approach

STATEMENT OF PROBLEM

Advanced cases of head and neck cancer involving the mandible often require surgical removal of diseased sections and subsequent replacement with donor bone. During the procedure, the surgeon must make decisions regarding which bones or tissues to resect. This requires balancing tradeoffs related to issues such as surgical access and post-operative function; however, the latter is often difficult to predict, especially given that long-term functionality also depends on the impact of post-operative rehabilitation programs.

PURPOSE

To assist in surgical decision-making, we present an approach for estimating the effects of reconstruction on key aspects of post-operative mandible function.

MATERIAL AND METHODS

We develop dynamic biomechanical models of the reconstructed mandible considering different defect types and validate them using literature data. We use these models to estimate the degree of functionality that might be achieved following post-operative rehabilitation.

RESULTS

We find significant potential for restoring mandibular functionality, even in cases involving large defects. This entails an average trajectory error below 2 mm, bite force comparable to a healthy individual, improved condyle mobility, and a muscle activation change capped at a maximum of 20%.

CONCLUSION

These results suggest significant potential for adaptability in the masticatory system and improved post-operative rehabilitation, leading to greater restoration of jaw function.

Age related impairments in ingestion from a large population based-sample

OBJECTIVES

Epidemiological data regarding the evolution of problems related to mastication and swallowing with age are lacking. This study aims to (i) describe changes in oral function with age, using data from a large French population, (ii) validate online, self-report uses of an ICF questionnaire in older persons, and (iii) assess whether impairment is related to avoidance of certain foods, xerostomia, body mass index (BMI) and oral health related quality of life (OHRQoL).

METHODS

Volunteers aged ≥18 years with internet access completed a series of questionnaires on sociodemographic, anthropometric and oral health characteristics (oral function, Xerostomia Index (XI), OHRQoL, reasons for avoidance of certain food). Oral function was assessed using items derived from the International Classification of Functioning (ICF). Five ICF items related to ingestion function and six items related to activities and participation were used. A validation study was undertaken to identify those with poor chewing ability and low salivary flow amongst older participants reporting impairment.

FINDINGS

39 597 individuals were included. The prevalence of individuals with impairment for ICF items related to ingestion function and oral activity (eating, drinking and speaking), and the percentage of participants with poor OHRQoL increased significantly with age (p < 0.001). Each ICF item was significantly associated with OHRQoL (p < 0.001), XI (p < 0.001), BMI (p < 0.001) and avoidance of certain food due to chewing or swallowing difficulties.

CONCLUSION

Overall, 21.5% and 13.5% of the study population had chewing and/or biting impairments respectively, which might affect food selection and consumption. These findings raise individual and population-based issues. Further studies are needed to assess whether impairment in oral function might increase frailty in older individuals, and also to compare data with those from other countries.

Age-related difference in oral adaptation to masticatory perturbation

OBJECTIVES

Mastication can be influenced by intraoral perturbation (e.g., hard food). We developed the masticatory perturbation task (MPT) to assess the perturbation effect during mastication and quantify the degree of adaptation to masticatory perturbation in younger and older adults.

DESIGN

Thirty-eight younger and 38 older participants completed the MPT, which consisted of three trials assessing masticatory performance (MP) without perturbation (i.e., the baseline condition) and three trials assessing MP with perturbation (i.e., the perturbation condition). Perturbation was implemented by concurrently chewing test food on the preferred side and a drinking straw on the nonpreferred side. We estimated the perturbation effect as the ΔMP between the baseline and perturbation conditions and the adaptation effect as the ΔMP between the third and the first trials for both age groups.

RESULTS

We found a significant perturbation effect, i.e., a lower MP in the perturbation condition than in the baseline condition, and an adaptation effect, i.e., a higher MP in the third trial than the first trial, in both groups. Moreover, the older group showed a lower degree of adaptation than the younger group.

CONCLUSION

The masticatory perturbation task revealed the perturbation effect during mastication and the adaptation to masticatory perturbation. The results revealed an association between age and masticatory adaptation.

Association between Self-Perception of Chewing, Chewing Behavior, and the Presence of Gastrointestinal Symptoms in Candidates for Bariatric Surgery

Given the changes in the digestive tract post-bariatric surgery, adapting to a new pattern of eating behavior becomes crucial, with special attention to the specifics of chewing mechanics. This study aimed to investigate the association between self-perception of chewing, chewing behavior, and the presence of gastrointestinal symptoms in preoperative patients undergoing bariatric surgery. Sixty adult candidates for bariatric surgery at a public hospital in Belém (Brazil) were analyzed. Participants predominantly exhibited unilateral chewing patterns (91.6%), a fast chewing rhythm (73.3%), a large food bolus (80%), liquid intake during meals (36.7%), and 41.7% reported that chewing could cause some issue. Significant associations were found between the perception of causing problems and chewing scarcity (p = 0.006), diarrhea (p = 0.004), absence of slow chewing (p = 0.048), and frequent cutting of food with front teeth (p = 0.034). These findings reveal a relationship between the perception of chewing problems and chewing scarcity, presence of diarrhea, and fast chewing.

Semidirect Resin Composite Veneers in a Patient with Bruxism

This case report details the esthetic rehabilitation of a 32-year-old male patient suffering from sleep bruxism, primarily manifesting as a fracture and significant loss of tooth structure in the anterior maxillary central incisors. To address these concerns, the patient underwent a restorative treatment involving the application of semidirect resin composite veneers on the maxillary incisors and direct resin composite restoration on the incisal regions of the maxillary canines. This approach not only restored the functional integrity of the teeth but also significantly enhanced the patient's esthetic appearance.

Assessment of Oral Masticatory Muscle Activity With Different Chewing Gums: A Cross-Sectional Study Based on Electromyogram Analysis

BACKGROUND

Facial muscles, particularly those involved in mastication, play a pivotal role in the chewing process. Despite their influence on chewing, these muscles undergo alterations during mastication. Examining the relationship between chewed substances and muscle activity can provide insights into various pathological processes and aid in the development of therapeutic chewing techniques.

AIM

This study aimed to evaluate the impact of different commercially available chewing gums on the activity of key masticatory muscles.

METHOD

Twenty-two participants were recruited for the study. They were instructed to chew four commercially available gums: group 1 comprised sugar gum with a strong flavor; group 2 included gum containing sorbitol; group 3 consisted of gum containing xylitol; and group 4 provided sugar gum with a mild flavor. Electromyogram (EMG) recordings were utilized to assess muscle activity. Various aspects of muscle activity, including chewing time, maximum muscle potential, and coordination between different muscles, were evaluated. Data tabulation and analysis were performed using IBM SPSS software version 23.0 (IBM Corp., Armonk, NY).

RESULT

Analysis revealed that in terms of temporalis symmetry, group 2 exhibited the highest mean deviation, while for masseter symmetry, group 3 demonstrated the highest mean deviation. The total deviation for the temporalis and masseter muscles was 72.16% and 65.55%, respectively, indicating greater symmetry in the temporalis muscle. Additionally, group 3 displayed the highest mean deviation in both left and right-sided synergic activity of the muscles. The total deviation for the right and left sides was 64.34% and 65.67%, respectively.

CONCLUSION

The findings suggest that sugar-free chewing gums elicit increased muscle activity compared to sugar-containing chewing gums. Furthermore, the utilization of calorie-free chewing gums with a firm texture was associated with better-coordinated muscle activity. These results provide valuable insights into the effects of different chewing gums on masticatory muscle function and coordination, which may have implications for therapeutic interventions and oral health management.

Does malocclusion affect ingestion: a systematic review

OBJECTIVES

The multifactorial aspect of malocclusions and their consequences on ingestion function is rarely described in the literature. The aims of this review are (i) to investigate the relationship between oral ingestion and malocclusion and (ii) to gather malocclusion tools that could help screen subjects at risk of malocclusion-related ingestion disorders.

MATERIAL AND METHODS

A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P 2015) guidelines. The analysis methods and inclusion criteria have been documented in a protocol published in the Prospective International Register of Systematic Reviews (PROSPERO) under the registration number CRD42023395840. The bibliographic search involved the PubMed®, Cochrane and PROSPERO databases.

RESULTS

A total of 29 articles published between 2007 and 2023 were retained by the search criteria for the qualitative synthesis. Twenty of the studies found that the severity of malocclusion has a negative impact on oral ingestion. This review highlights that malocclusion and ingestion impairments are associated but it is not possible to determine causality due to the observational approach of many of the studies.

CONCLUSION

Malocclusion has a negative impact on ingestion function. During orthodontic consultations, particular interest should be directed towards chewing, biting, and swallowing disorders, which can affect patients' nutritional status. This review offers arguments for designing further studies assessing the extent to which malocclusions may affect nutritional status.

CLINICAL RELEVANCE

Orthodontic treatment should focus on improving patients' ingestion.

Clinical and digital assessment of tooth wear

The aim of this study was to compare the assessment of tooth wear performed on digital models with the one conducted at the clinical examination. Seventy-eight volunteers (29 males and 49 females, age range 20-30 years) with at least 24 teeth, normal oral function, and a neutral transverse relationship were examined. During the clinical examination, dental wear was registered according to the Basic Erosive Wear Examination (BEWE) index. Subsequently, the BEWE index was blindly applied by two examiners on digital models obtained from the volunteers. Data were analyzed using weighted Cohen's kappa coefficient and correlation tests with a confidence interval of 95%. All volunteers showed signs of tooth wear. Anterior teeth showed increased severity of tooth wear than first molars. Early loss of tooth substance could be identified on the digital models, including in areas with challenging direct intraoral visual access. Approximately 50% of the scores based on clinical examination agreed with those based on examination of digital models (k = 0.543, p < 0.01). A moderate, positive correlation was observed between scores registered clinically and on digital models (Spearman's rho = 0.560, p < 0.001). Considering the rather low agreement between the clinical and digital scores, alternatives to using BEWE on digital models are needed.

Associations of oral health status and swallowing function with cognitive impairment in the aging population: a cross-sectional study

BACKGROUND

The purpose of this study was to investigate the relationships of oral health status and swallowing function with cognitive impairment in community-dwelling older adults from Changsha, Hunan Province, China.

METHODS

In this cross-sectional study, we analyzed the data of 215 participants aged ≥ 50 years which were retrieved from the Xiangya and Panasonic mild cognitive impairment (MCI) Study, a community-based study conducted among the residents of the urban areas of Hunan province in China. Demographic information of all participants was collected. We determined oral function by evaluating oral hygiene, oral dryness, occlusal force, tongue pressure, chewing function, swallowing function, remaining teeth number, and other indicators. The mini-mental state examination (MMSE) was used to screen for cognitive function. The relationship between each oral function evaluation item and cognitive function was investigated using correlation analysis. The associations between oral health status and swallowing function with cognitive impairment were inferred using multiple regression analysis.

RESULTS

The general characteristics of participants showed statistically significant correlation coefficients in number of teeth remaining (p = 0.003) and number of teeth lost (p < 0.0001). Almost half of the 25 participants (48%) were aged from 70-80 years. Only 25 older adults (11.6% of the participants) were determined to have cognitive impairment by MMSE sores less than 24. Tongue pressure in male participants was the only significant independent variable that was associated with cognitive impairment (p = 0.01971). The results indicate that male participants with lower MMSE scores had a relative deficiency in tongue pressure.

CONCLUSIONS

In this cross-sectional study, the oral health status and swallowing function of participants were in relatively good condition and showed low correlations with cognitive impairment. However, lower tongue pressures were associated with lower MMSE scores in males, indicating it could serve as a novel oral function index for evaluating cognitive impairment.

Association of masticatory efficiency with deep carious lesions in children

PURPOSE

Masticatory efficiency is defined as an individual ability to grind and pulverize food material, and can be influenced by many factors. This research aimed to investigate the association between masticatory efficiency and deep carious lesion.

METHODS

The research included 48 children (24 male, 24 female) aged from 3 to 14 years. Participants were allocated to two groups; children with no or with only incipient carious lesions were included in the first group (ICDAS levels 0, 1, or 2), and children with bilateral deep carious lesions that are ICDAS levels 4, 5, and 6 were included in the second group. Information on dental parameters (dental status, ICDAS level of each carious lesion), and level of pain (Wong-Baker scale) were collected from each participant. Participants chewed Optosil® test food for 20 masticatory cycles, and chewed particles were analyzed by the optical scanning method.

RESULTS

There is a significant difference in masticatory efficiency variables (number of chewed particles, minimal and maximal Feret diameter, Sauter mean diameter, a mean and total surface of particles) between groups. A positive significant correlation is observed between WBS level and time needed for masticatory performance in a group of children with deep carious lesions.

CONCLUSION

Deep carious lesions in children are associated with a decrease in masticatory efficiency. Moreover, children with carious lesions that provoke a higher level of pain take more time for masticatory cycles.

Changes in the occlusal function of orthognathic patients with vertical malformations after combined orthodontic surgical therapy: a prospective clinical study

The aim of this study was to assess the changes in occlusal patterns during combined surgical and orthodontic therapy in patients with vertical jaw malformations. Twenty-six orthognathic patients (18 female, eight male; median age 25 years, interquartile range 11.5 years) and 10 control patients (five female, five male; median age 29.8 years, interquartile range 13.5 years) recruited from neutral configured patients attending the Department of Orthodontics, were investigated. Based on cephalometry, the patients were grouped into vertical skeletal configurations of either open, deep, or natural bite cases. Registrations of the occlusal contacts were taken using a digital occlusal sensor immediately before surgery and at 9 months after the surgical intervention. Before the intervention, open and deep bite patients showed significantly less efficient occlusal patterns than the untreated controls regarding total tooth contact (P < 0.001), time of occlusion (P = 0.002), occlusal asymmetry (P = 0.001), anterior tooth contact (P < 0.001), and posterior tooth contact (P < 0.001). After surgery, the parameters in the deep bite patients were similar to those in the controls; however, in open bite patients, total tooth contact (P = 0.003), occlusal asymmetry (P = 0.011), and posterior tooth contact (P = 0.035) differed significantly. In conclusion, combined orthodontic and surgical correction of vertical malocclusions was found to improve occlusal function in patients with deep bite to the level of controls.

Periodontitis assessed with a new screening tool and oral health-related quality of life: cross-sectional findings among general-population adults

INTRODUCTION

Periodontitis, as a chronic, multifactorial inflammatory disease, has complex relationships with other diseases and ultimately with well-being. The aim of this cross-sectional study was to investigate the association between self-report periodontitis, as measured with the recently developed and validated modified Periodontal Screening Score (mPESS), and oral health-related quality of life (OHRQol) in a large population-based sample derived from the French NutriNet-Santé e-cohort.

METHODS

The sample was composed of 32,714 adults (75.5% women) with a mean age of 48.8 ± 13.9 years. Periodontitis was assessed based on age, smoking, and oral health status data obtained in 2011-2012, which allowed calculating the mPESS. An mPESS ≥ 5 was used to identify individuals at risk of severe periodontitis (main exposure). OHRQoL was measured with the Oral Health Impact Profile (OHIP-14) (main outcome) and the total score was dichotomized for analysis. Multivariable logistic regression analyses, considering physical health status, dietary and lifestyle confounding variables, were performed.

RESULTS

Overall, 6407 participants (19.6%) were at a high risk of severe periodontitis. A total of 7383 participants (22.6%) presented a relatively poor OHRQoL (OHIP-14 > 8, highest quartile). In the multivariable model, each of the following variables was independently and significantly associated with lower OHRQoL: older age (50-64 years), female sex, obesity, snacking between meals, frequent consumption of soft drinks and sweets/chocolate, risk of severe periodontitis, and having < 20 natural teeth were significantly. An mPESS ≥ 5 showed the highest odds for relatively poor OHRQoL (OR = 3.45; 95% CI 3.21-3.72).

CONCLUSION

The results support the association between periodontitis and OHRQoL in non-clinical samples. The use of mPESS could be tested in future prevention programs aiming at improving OHRQoL.

Pterygoid muscle activity in speech: A preliminary investigation

BACKGROUND

Speaking depends on refined control of jaw opening and closing movements. The medial pterygoid muscle (MPT), involved in jaw closing, and the lateral pterygoid muscle (LPT), involved in jaw opening, are two key mandibular muscles in mastication and are likely to be recruited for controlled movements in speech.

OBJECTIVES

Three hypotheses were investigated, that during speech the MPT and LPT: (1) were both active, (2) but exhibited different patterns of activity, (3) which fluctuated with the vowels and consonants in speech.

METHODS

Intramuscular EMG recordings were made from the right inferior head of the LPT and/or the right MPT in five participants during production of 40 target nonsense words (NWs) consisting of three syllables in the form /V₁ C₁ V₂ C₂ ə/ (V = vowel; C = consonant; ə = unstressed, reduced vowel), spoken by each participant 10 times per NW; analysis focussed on the target syllable, C₁ V₂ .

RESULTS

Both MPT and LPT exhibited robust increases in EMG activity during utterance of most NWs, relative to rest. Peak LPT activation was time-locked to the final part of the target consonant (C₁ ) interval when the jaw begins opening for the target vowel (V₂ ), whereas peak MPT activation occurred around the temporal midpoint of V₂ , when the jaw begins closing for C₂ . EMG amplitude peaks differed in magnitude between "high" vowels, i.e., for which the tongue/jaw are high (e.g., in SEEK), and "low" vowels, i.e., for which the tongue/jaw are low (e.g., in SOCK).

CONCLUSIONS

These novel findings suggest a key role for the LPT and MPT in the fine control of speech production. They imply that speech may impose major synergistic demands on the activities of the MPT and the LPT, and thereby provide insights into the possible interactions between speech activities and orofacial activities (e.g. mastication) and conditions (e.g. Temporomandibular Disorders) that involve the masticatory muscles.

Dental Criteria Could Alert for Malnutrition Risk and Inappropriate Choice of Food Texture in Older Subjects with Dementia: An Analytical Cross-Sectional Study

Oral health indicators are usually collected to alert for the presence of infectious diseases, but the impact of poor oral health on the nutritional status of older people with dementia is often neglected. This study aims to explore the relationship between the number of posterior dental functional units (PFUs) and the anthropometric measure of malnutrition, the mid-upper arm circumference (MUAC), in older people with dementia while controlling for other variables, and to analyze whether the number of PFUs is considered when adjusting the texture of the food provided at mealtimes. A total of 103 individuals who were 70 years or older with dementia were recruited from seven institutions. Cognitive impairment was assessed using the Mini Mental State Examination. Data were collected from medical records (sociodemographic characteristics, presence of chronic diseases, prescribed medications, results of serum albumin level), as well as questionnaires (type of feeding routes, type of food texture, supplements intake, Activity of Daily Living index), clinical examinations (MUAC), and oral health parameters (PFUs, oral dryness, oral hygiene). MUAC was the dependent outcome variable. MUAC was associated with the number of PFUs (p = 0.032); participants with PFU ≤ 4 were 7.5 times more likely to have MUAC < 21 cm than others. Other associations were found between MUAC and albumin level (OR = 12.5; p = 0.001), modified food texture (OR = 4.2; p = 0.035), and length of institutional stay (OR = 5.2; p = 0.033); however, the type of oral feeding was not significantly related to the number of PFUs (p = 0.487) so there is an inadequate correlation between food texture and oral health status. Similar to MUAC, the number of PFUs could be an oral anthropometric criterion that is recorded during routine hygiene care to alert for the risk of malnutrition and the inappropriate choice of food texture in older individuals with dementia.

Relationship between Oral Health Status and Oropharyngeal Dysphagia in Older People: A Systematic Review

The purpose of this review is to investigate the relationship between oral health status and oropharyngeal dysphagia (OD) in older people and to collect a list of oral health indicators that can enable carers and health professionals to screen for risk of dysphagia in older people during oral examinations. A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P 2015) guidelines. The analysis methods and inclusion criteria were documented in a protocol published in the Prospective International Register of Systematic Reviews (PROSPERO) under the registration number CRD42020140458. A total of 19 articles published between 2002 and 2020 were retained by the search criteria for the qualitative synthesis. Eighteen studies demonstrated at least one positive association between an oral health component (dental, salivary and/or muscular) and dysphagia. This review highlights that oral health and OD are associated but was not able to determine causality. The lack of scientific evidence could be explained by the observational approach of the majority of the studies and the irrelevant choice of oral health indicators. A relationship may exist between oral health and dysphagia, but this review highlights the lack of valid and standardized oral health indicators that would be needed to assess the impact of oral health on the overall health status of individuals.

Prosthodontic Treatment in Patients with Temporomandibular Disorders and Orofacial Pain and/or Bruxism: A Review of the Literature

Temporomandibular disorders are a group of conditions affecting the temporomandibular joints, the jaw muscles, and related structures. Patients with temporomandibular signs and/or symptoms frequently present with indications for prosthetic treatment. The management of these patients aims to achieve patient comfort, occlusal stability, and the complex restoration of the teeth. The goal of this review is to provide an overview of the relationship between prosthodontics and temporomandibular disorders and/or bruxism with a focus on the cause-and-effect implications and the strategies for planning prosthetic treatments in patients with temporomandibular disorders and/or bruxism.

Effect of Dental Course Cycle on Anatomical Knowledge and Dental Carving Ability of Dental Students

This study assessed the effect of the course cycle on theoretical knowledge of dental morphology and the dental carving ability of dental students. Thirty-two dental students from the third semester (initial cycle) and 30 students from the eighth and tenth semesters of the dental course (end cycle) had their theoretical knowledge on dental morphology assessed using a questionnaire with ten closed questions. Their dental carving ability was also assessed using wax carvings in macro models of plaster (for the third [S3] and eight [S8] semesters) and natural-sized artificial teeth (for the tenth [S10] semester). The teeth chosen for the dental carving activity were #16 and #47. The scores were statistically analyzed using the t-test, Kruskal-Wallis test, and Mann-Whitney test (α = 0.05). Students from the initial cycle presented better theoretical knowledge than the other groups did (P < 0.007). No significant differences in carving score were found between the initial and end cycles (P > 0.05), although S10 students obtained a higher score for teeth #16 and #47 (P < 0.05). Natural-sized artificial teeth received a higher evaluation score in dental carvings than the macro models (P < 0.001). Within the limits of this study, it was possible to conclude that students from the initial cycle (S3) presented higher theoretical knowledge, whereas no difference in carving ability was observed between the initial and end cycles. The tenth semester (S10) students performed dental carvings with better quality. Furthermore, carvings in natural-sized artificial teeth presented better quality compared with the macro models.

Reduced masticatory function predicts gastroesophageal reflux disease and esophageal dysphagia in patients referred for upper endoscopy: A cross-sectional study

BACKGROUND

The role of mastication on gastroesophageal reflux disease (GERD) is unknown.

AIMS

To assess whether reduced masticatory function predicts GERD and esophageal dysphagia in patients investigated with upper endoscopy.

METHODS

In this cross-sectional study, 179 adult patients referred for elective upper gastrointestinal endoscopy agreed to participate. Before endoscopy, an expert dentist performed an oral examination and scored chewing function in three levels (normal, regular, and reduced). Patients replied questionnaires for assessment of GERD (heartburn, regurgitation, and dysphagia), xerostomia, and mastication (normal, regular, and reduced). Poor chewing was defined when either oral examination or mastication questionnaire rated the chewing function as reduced. Associations of mastication with GERD and dysphagia were estimated using Poisson regression.

RESULTS

Eleven patients were excluded. Among 168 analyzed (aging 49.8 ± 15.5 years; 58.9% women), 46 had reduced masticatory function (27.4%), and 122 had regular/normal mastication (72.6%). Reduced mastication was associated with GERD [PR = 1.38 (95%CI 1.12 - 1.70)], adjusting for age, and with esophageal dysphagia [PR = 2.03 (95%CI 1.02 - 4.04)], adjusting for age and xerostomia.

CONCLUSIONS

In outpatients referred for upper gastrointestinal endoscopy, reduced masticatory function defined by an expert dentist may be a risk factor for GERD and esophageal dysphagia.

Effect of Different Ceramic Materials on Fatigue Resistance and Stress Distribution in Upper Canines with Palatal Veneers

OBJECTIVE

 The aim of this study was to evaluate, by means of a fatigue life test, different ceramic materials used in palatal veneers to restore the canine guidance.

MATERIALS AND METHODS

 Forty-five standardized anatomical preparations were made in extracted healthy human canines with 1.2 uniform thickness. Samples were scanned, restorations were designed and milled in polymer-infiltrated ceramic network (PICN, Vita Enamic), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity), and high translucent yttrium oxide-stabilized tetragonal zirconia (YZHT, Vita YZHT). Dental preparations were etched, restorations were processed according to the manufacturers' recommendations, and adhesively cemented. Then, three samples of each group were tested with load-to-fracture to determine the fatigue parameters. In addition, the palatal veneers stresses were evaluated using numerical models through finite element analysis.

RESULTS

 The mean of the monotonic test for PICN, ZLS, and YZHT was 674.18 N, 560.5 N, and 918.98 N, respectively. The StepWise test was performed until specimen fracture or until suspension of the test after 1.2 × 10⁶ cycles. Regarding survival, using the Kaplan-Meier method, PICN presented results for the mean and median of 245.21 N and 225 N, respectively; ZLS had an average of 175.76 N and a median of 168 N, and YZHT with an average of 383.30 N and a median of 366 N. Regarding the Weibull method, PICN showed results of 5.43 β and 264 η for form and scale, respectively; ZLS had 36.14 β for form and 380.67 η for scale; and YZHT presented 4.95 β for form and 417.38 η for scale. The highest stress value was calculated for YZHT, ZLS, and PICN, respectively.

CONCLUSIONS

 It was possible to conclude that all tested materials have the possibility of being used for rehabilitation of upper canines' palatal surface.

Effects of food particle loss on the evaluation of masticatory ability using image analysis

PURPOSE

To examine how particle loss affects the evaluation of masticatory ability using the image analysis method.

METHODS

The subjects were divided into two groups:Y-group (healthy young adults: 10 male, 10 female; mean age 27.6 ± 1.9 years), and D-group (denture wearing older adults: 13 male, 9 female; mean age, 75.1 ± 5.3 years). Raw carrots, peanuts, and a combined test food from 5 daily food materials (mixed foods) were selected as test foods. Images of the boluses were captured and processed after the subjects freely masticated the test foods until the point of swallowing or completed half strokes of total chewing cycles. The median particle size (X₅₀) was calculated from the data for each particle. We compared X₅₀ calculated from all particles obtained from the masticatory bolus (as X_50N) with the X₅₀ of only selectively larger particles (as X_50R).

RESULTS

Significant correlations were observed between X_50N and X_50R (p < 0.01) determined in almost all masticatory conditions. In particular, for particle sizes of 2 mm or more, the correlation coefficient between X_50N and X_50R was notably strong (r > 0.75).

CONCLUSION

The method of analyzing only larger particles makes it possible to evaluate masticatory ability without losing the characteristics of the original particle size distribution of the entire bolus. This finding can be applied for the evaluation of masticatory ability, especially among older adults who have difficulty retrieving the total amount of test food due to decreased activities of daily living.

Poor dental condition is a factor of imbalance of the nutritional status at the outset of management of head and neck cancer

OBJECTIVES

To determine whether deterioration of dental condition at the outset of management of head and neck cancer (HNC) is a nutritional risk and whether social deprivation is a cause of the poor dental condition observed in HNC patients.

MATERIAL AND METHODS

A nutritional assessment form (NAF) and the Nutrition Risk Index (NRI) were used to standardize the nutritional status of 108 patients at the outset of management of HNC (2017-2019). The NAF includes assessment of weight loss over the past 3 months, the amount and difficulty of food intake, and the presence of digestive disorders. Dental condition was assessed by the decayed, filled, and missing teeth acopre (DFM) index and the masticatory coefficient (MC). Dental status and social deprivation were correlated with the EPICES score.

RESULTS

A correlation was found between the extent of weight loss and dental condition. The MC was higher in absence of weight loss (46% vs. 27%, p = 0.03) and the DMF lower when weight loss was less than 5% (22.3 vs. 26.9 if > 5% loss of weight, p = 0.005). No correlation was found between dental status and nutritional status. Social deprivation was associated with a lower MC (26% vs. 50%, p < 0.001).

CONCLUSION

Dental condition is a risk factor for weight loss at the outset of management of HNC but is not a determinant of nutritional status. Clinical relevance Dental condition is no longer considered simply as a source of potential complications after radiotherapy but also as an important factor for nutritional status.

Masticatory function in children with Down syndrome

The objective was to study masticatory function of 8 to 10-year-old children with Down syndrome (DS) through the evaluation of maximum occlusal force and masticatory performance (via medium particle size) and compare it to that of children of the same age without DS.

METHODS

A convenience sample of eight, 8-10-year-old children with DS were included in this cross-sectional study. The study had ethical approval and parents provided informed consent. Exclusion criteria were large carious lesions, dental pain or previous orthodontic/orthopedic treatment. Masticatory performance was evaluated with an artificial test food (Optosil Comfort®) after 20 cycles and at swallowing threshold. The chewed material was collected, dried and sieved. The material on each sieve was weighed; the weights were used to calculate medium particle size. Maximum occlusal force (1st permanent molars) was determined using the GM10 Nagano Keiki Co.™ portable transducer. The number of cycles until swallowing threshold, cycle and sequence durations were also compared. The data for the reference group (n = 32) came from a previous study in children of the same age. Descriptive statistics as well as comparisons with Mann-Whitney tests and simple and multiple regression analysis were performed. Cutoff was set at p≤.05.

RESULTS

Medium particle size is larger by 44% after 20 chewing cycles and 75% at swallowing threshold (p<.05) in children with DS. Median maximum occlusal force was 254 kN in DS children and 499 kN in children without the syndrome (p<.001). 48% of the variance in maximum occlusal force is explained by having DS. There were also significant differences in sequence and cycle durations. All significant differences had large effect sizes (˃1). Although the children with DS chewed more cycles before swallowing threshold the difference was not significant.

CONCLUSIONS

Children with DS have approximately 50% of the masticatory performance and maximum occlusal force of children of the same age without DS. These findings can be associated to the feeding problems reported in children with DS.

Poor Masticatory Capacity and Blood Biomarkers of Elevated Cardiovascular Disease Risk in the Community: The Paris Prospective Study III

[Figure: see text].

The Association between Age-Related Changes in Oral Neuromechanics and Alzheimer's Disease

The global population of 80 years and older is predicted to reach 437 million by 2050. As overall brain structure and function progressively degrades, older and younger adults show differences in sensorimotor performance and brain activity in the sensorimotor regions. Oral sensorimotor functions are an important area of focus in natural aging and Alzheimer’s Disease (AD) because oral health issues are commonly found in both elderly and AD populations. While human behavioral studies on changes in oral sensorimotor functions abound, very little is known about their neuronal correlates in normal and pathological aging.

Consensus on the terminologies and methodologies for masticatory assessment

A large number of methodological procedures and experimental conditions are reported to describe the masticatory process. However, similar terms are sometimes employed to describe different methodologies. Standardisation of terms is essential to allow comparisons among different studies. This article was aimed to provide a consensus concerning the terms, definitions and technical methods generally reported when evaluating masticatory function objectively and subjectively. The consensus is based on the results from discussions and consultations among world‐leading researchers in the related research areas. Advantages, limitations and relevance of each method are also discussed. The present consensus provides a revised framework of standardised terms to improve the consistent use of masticatory terminology and facilitate further investigations on masticatory function analysis. In addition, this article also outlines various methods used to evaluate the masticatory process and their advantages and disadvantages in order to help researchers to design their experiments.

Association between cognitive health and masticatory conditions: a descriptive study of the national database of the universal healthcare system in Japan

Cognitive health is subject to decline with increasing numbers of lost teeth which impacts mastication. This study is a descriptive data analysis of the association between masticatory and cognitive conditions using a large database. We obtained the dental and medical records from Japan's universal healthcare system (UHCS) from the national database in 2017. The data from 94% of the Japanese population aged 65 and over is included. It is inclusive of diagnostic codes for various types of cognitive impairment, as well as dental treatment records from 2012 to 2017. The cognitive impairment group was compared to those without a diagnosis of cognitive impairment. Crude odds ratio between loss of mastication with natural teeth (exposure) and cognitive impairments (outcome) were compared. Patients who have lost masticatory function are likely to have cognitive impairment with an odds ratio of 1.89 (p<0.0001) for early elderly (aged 65-75) and 1.33 (p<0.0001) for advanced elderly (over 75). Patients who are edentulous and function with complete dentures are likely to have cognitive impairment with an odds ratio of 2.38 (p<0.0001) and 1.38 (p<0.0001), respectively. The data shows a convincing and significant result of an association between cognitive health and oral health, related to masticatory conditions.

Radiological Evaluation of Stainless Steel Crowns Placed on Permanent Teeth in Patients Treated under General Anaesthesia

Evidence-based evaluations of dental treatment are needed to support the development of special care dentistry services. This retrospective study was designed to collect and analyse X-ray images of permanent teeth restored with stainless steel crowns (SSC) in patients treated under general anaesthesia. Between 2013 and 2019, 360 permanent molars were crowned with SSCs in 198 adult patients. One calibrated investigator used an original validated tool to evaluate four radiographic criteria for molars restored with SSCs: (i) marginal adaptation; (ii) interdental proximal contact; (iii) the presence of glass ionomer cement overflow; and (iv) the loss of alveolar bone. Overall, no defect or a minor defect was reported for the majority of SSCs for the criteria “Marginal adaptation” (62.5%, n = 320), “Proximal contact” (82.2%, n = 236) and “Cement overflow” (95.8%, n = 337). Alveolar bone resorption was reported in 8.3% of cases, n = 14, after a mean period of 8.9 ± 14.3 months. It was shown that the restoration of permanent teeth using SSCs placed under general anaesthesia presents a low risk of periodontal morbidity in the medium term when assessed radiographically.

A Comprehensive Approach Limiting Extractions under General Anesthesia Could Improve Oral Health

Access to dental treatment could be difficult for some patients due to dental phobia or anxiety, cognitive or sensorial disabilities, systemic disorders, or social difficulties. General anesthesia (GA) was often indicated for dental surgery, and there is almost no available data on adapted procedures and materials that can be applied during GA for maintaining functional teeth on the arches and limiting oral dysfunctions. This study evaluates changes in oral health-related quality of life and mastication in a cohort of uncooperative patients treated under GA according to a comprehensive and conservative dental treatment approach. Dental status, oral health-related quality of life, chewed bolus granulometry, kinematic parameters of mastication, and food refusals were evaluated one month preoperatively (T0), and then one month (T1) and six months post-operatively (T2). One hundred and two adult patients (mean age ± SD: 32.2 ± 9.9 years; range: 18–57.7) participated in the preoperative evaluation, 87 were treated under GA of which 36 participated in the evaluation at T1 and 15 were evaluated at T2. Preoperative and postoperative data comparisons demonstrated that oral rehabilitation under GA helped increase chewing activity and oral health-related quality of life. The conditions for providing dental treatment under GA could be arranged to limit dental extractions in uncooperative patients.