Systematic review of measurement properties of methods for objectively assessing masticatory performance

Development and validation of an AI-driven tool to evaluate chewing function: a proof of concept

BACKGROUND

Masticatory function is an important determinant of oral health and a contributing factor in the maintenance of general health. Currently, objective assessment of chewing function is a clinical challenge. Previously, several methods have been developed and proposed, but implementing these methods in clinics may not be feasible. Therefore, more efforts are needed for accurate assessment of chewing function and clinical use.

AIM

The study aimed to establish a proof of concept for development and validation of an automated tool for evaluating masticatory function.

METHODS

YOLOv8, a deep neural network, was fine-tuned and trained to detect and segment food fragments. The model's performance was assessed using bounding box recall metrics, segmentation metrics, confusion matrix, and sensitivity values. Additionally, a separate conversion test set evaluated the model's segmentation performance using physical units, demonstrated with Bland-Altman diagrams.

RESULTS

The YOLOv8-model achieved recall and sensitivity rates exceeding 90 %, effectively detecting and classifying food fragments. Out of 316 ground truth fragments, 301 were correctly classified, with 15 missed and 5 false positives. The Bland-Altman diagram indicated general agreement but suggested a systematic overestimation in measuring the size of post-masticated food fragments.

CONCLUSION

Artificial intelligence presents a reliable approach for automated analysis of masticatory performance. The developed application proves to be a valuable tool for future clinical assessment of masticatory function.

CLINICAL SIGNIFICANCE

The current study provides a proof of concept for development of an automated tool for clinical assessment of masticatory function.

Masticatory function between chewing with and without wearing clear thermoplastic appliances

BACKGROUND

Clear thermoplastic materials are used in a variety of oral appliances. In some situations, patients may wear clear thermoplastic appliances while eating. However, the effect of wearing clear thermoplastic appliances on chewing efficiency is unknown. This study aimed to evaluate the differences in masticatory function between chewing with and without wearing clear thermoplastic retainers over a 6-month period, and its associated factors.

METHODS

Thirty patients who received upper and lower clear retainers after debonding fixed appliances were examined for objective and subjective masticatory function at retainer delivery (T0), 3-month (T1), and 6-month follow-ups (T2) in two conditions: with and without wearing their retainers while chewing. The objective method used multiple sieves reported as the median particle size (MPS). The food intake ability (FIA) test served as the subjective method. Paired t-test was used to compare the outcomes between chewing with and without retainers at each evaluation time point. Repeated measures ANOVA followed by the Bonferroni post-hoc test was used to compare the outcomes between the three evaluating time points. Multivariable linear regression analysis was performed to assess whether age, sex, and extraction/non-extraction was associated with these effects.

RESULTS

The MPS was significantly greater when chewing with retainers compared with chewing without them at T0 (P < 0.05), however, it was not significantly greater at T1 and T2 (P > 0.05). The MPS with and without the retainers tend to decrease between T0, T1 and T2. In particular, the MPS while chewing with retainers significantly decreased between T0 and T1. The total FIA score and FIA subscores for hard and soft food were significantly lower when eating with retainers at T0 (P < 0.05), however, all FIA scores when eating without retainers did not significantly change between T0, T1, and T2. No significantly associated factors were identified.

CONCLUSIONS

Wearing clear retainers while chewing decreases objective and subjective masticatory function immediately after completing orthodontic treatment. However, this significantly improved to levels comparable to chewing without retainers after a 3-month follow-up. Age, sex, and extraction/non-extraction treatment were not associated with the difference in masticatory function while chewing with and without wearing the retainers.

Orofacial dysfunction after stroke-A multidisciplinary approach

OBJECTIVE

This paper describes the study protocol in an ongoing clinical trial evaluating oral screen training as part of a post-stroke rehabilitation programme. Baseline data were related to four domains: dysphagia, lip function, masticatory performance and patient-related outcome measures (PROM).

BACKGROUND

Stroke is one of the most common causes of disability-adjusted life years, and dysphagia is a common remaining problem after stroke. Rehabilitation using oral screen training has been suggested to improve swallowing, but evidence is still insufficient.

MATERIALS AND METHODS

Patients diagnosed with stroke with persisting objective and/or subjective swallowing dysfunction after primary rehabilitation were assessed for eligibility. In total, 25 patients were included. Objective function was assessed by swallowing capacity test (SCT), lip force and masticatory performance, subjective function by EAT-10 and NOT-S and PROM by LiSat-11 and ESAS.

RESULTS

Baseline data presented a heterogeneous pattern with no significant association between objective and subjective dysfunction. Most of the participants (20/25) showed impaired swallowing capacity in SCT, and 23/24 revealed orofacial dysfunction according to NOT-S. The most common subjective item reported was chewing and swallowing problems (19/24).

CONCLUSION

The heterogenous findings in the included tests and the lack of correlations emphasise the importance of multidisciplinary approaches to identify objective and subjective orofacial post-stroke dysfunction in clinical practice to be able to offer evidence-based individualised care. The included participants were representative of stroke patients with dysphagia, which supports proceeding with the planned intervention.

[Geriatric assessment in dentistry : A review of chewing function tests]

Due to increasing life expectancy and the associated demographic changes, more and more people are dependent on care. To identify a possible need for dental treatment, chewing function tests as assessment instruments have proven their effectiveness. In this article, the reader is given an overview of existing chewing function tests and their implementation. It is important that a patient with pain should be presented to a dentist immediately, regardless of whether a chewing function test is performed. Furthermore, chewing function tests are not a substitute for routine dental examinations, but they could provide information to (dental) laypersons as to whether an appointment should be arranged in a dental practice or whether a dental consultation is necessary.

Evaluation of the Association of Chewing Function and Oral Health-Related Quality of Life in a Population of Individuals Aged ≥ 45 Years and Residing in Communities in Switzerland: A Cross-Sectional Study

PURPOSE

To analyse the association of masticatory performance and oral health-related quality of life in a representative population of individuals residing in communities in Switzerland aged ≥ 45 years.

MATERIALS AND METHODS

In total, 100 subjects completed two dedicated and validated questionnaires on their demographic data and the Geriatric Oral Health Assessment Index. A mixing ability test was performed for assessing masticatory performance. The qualitative analysis of the test was performed by categorizing the images into five categories, while the quantitative analysis was performed via a validated custom-made software.

RESULTS

Sixty-six samples could be analysed. Participants younger than 65 years of age showed significantly less frequent chewing deficiencies (17%) compared to those 65 years and older (50%, p < 0.01). However, retired participants had chewing deficiencies significantly more frequently (8%) compared to workers (51%, p < 0.01). A statistically significant positive association of having chewing deficiency was found between employment status (p < 0.01) and the presence of restorations (p = 0.04), while GOHAI did not show any statistically significant association. Overall, the enrolled subjects displayed moderate chewing function. Masticatory performance was positively associated with the number of present restorations.

CONCLUSIONS

The enrolled subjects residing in communities in Switzerland aged ≥ 45 years displayed moderate chewing function. Their masticatory performance was positively associated with the number of present restorations but not associated with oral health related quality of life (GOHAI).

Reliability between the two-colour chewing gum and the gummy-jelly tests used for the assessment of masticatory performance

OBJECTIVE

This study aimed to evaluate the reliability of two methods used to assess masticatory performance and attempt to correlate them to achieve interchangeability between the methods.

METHODS

Twelve healthy dentate volunteers (men = 6, women = 6; mean age = 28.3 ± 4.1) with no known dental or medical pathologies were requested to participate in this study. Each participant completed three masticatory performance assessments, including two two-colour mixing-ability tests using chewing-gums (CG: gum#1 and gum#2) and the gummy-jelly (GJ) test. For each method, participants created five samples each (total = 15 measurements per participant, gum#1 = 5, gum#2 = 5, GJ = 5). For the gum#1 and gum#2 methods, the predetermined chewing cycles were fixed at 10, 15, 20, 25 and 30 cycles, and for the GJ method, the time duration was fixed at 10, 15, 20, 25 and 30 s. The parameter measures were submitted to Z-score transformation, and Bland-Altman plots were generated to graphically compare the differences between two techniques against their means. Additionally, mountain plot was used to assess the cumulative distribution of measurement error between the methods.

RESULTS

A total of 180 measurements were recorded. There were significant correlations between the number of chewing cycles/chewing time and masticatory performance using the gum#1 (r = -.753; p < .001), gum#2 (r = -.838; p < .001) and GJ (r = .730). When all tests were considered together for each method, significant correlations were found (p < .001). A descriptive range of mean values aiming to produce reference value ranges for predictive purposes was achieved considering the interchangeably among the methods [CG = GJ (VoH-mg = dL): 10 cycle = 10 s: 0.329 = 110; 15 cycles = 15 s: 0.177 = 164; 20 cycles = 20 s: 0.130 = 205; 25 cycles = 25 s: 0.086 = 200; 30 cycles = 30 s: 0.077 = 267].

CONCLUSION

The strong correlations and high consistency between the two masticatory performance methods found in this study conclude that the two assessment methods are reliable and interchangeable. Further evaluations are warranted to arrive at a conversion formula for translation of the results between the two methods.

The use of color-changeable chewing gum in evaluating food masticability

PURPOSE

We assess masticatory performance using color-changeable chewing gum, which shifts from yellow-green to red upon chewing. Previous studies used a colorimeter to reveal the cut-off a* values of the gum's color (a* represents the degree of color between red and green) to determine which foods are masticable (masticable meat, masticable soft side dish, and inadequate masticatory performance). Since a more convenient method is required, we examined the validity and reliability of visual measurement using a color scale to indicate masticable foods by observing the chewing gum's color.

METHODS

Fifty patients (male, 48%), aged ≥ 65 (mean, 82.6) years were enrolled. Using color-changeable chewing gum, three groups were formed according to the cut-off a* values: masticable meat, masticable soft side dish, and inadequate masticatory performance. For the color scale classification, one physiatrist and one dietitian simultaneously, individually, and visually determined the chewing gum color and classified it into one of the three groups. Criterion-related validity was evaluated using the kappa coefficient of agreement between the results from the two methods. Inter-rater reliability was examined using the kappa coefficient of agreement between the three groups judged by the two raters on a color scale.

RESULTS

The kappa coefficients of the agreement for the classifications were 0.908 and 0.909 for the physiatrist and dietitian, respectively. The inter-rater agreement between two raters on the color scale was 0.938 for the kappa coefficient.

CONCLUSION

The color scale indicated masticable foods without a colorimeter. This method can be useful in older adult facilities and homes.

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.

The Effect of Caries on the Chewing Ability of Children: A Scoping Review

Childhood caries might have several effects on the children's general health and growth, including chewing ability. This study aims to identify the evidences found regarding the effect of caries on the chewing ability of children through a scoping review. A scoping review literature search was performed in three databases (Scopus, PUBMED, and Web of Science) without restricting the publicized year. The selected articles were using human as its subjects and aiming to analyze the effects of caries on mastication ability in children. Ten articles matched the inclusion criteria of this review. All the articles suggested a deleterious effect of caries on masticatory performance, maximum bite force, swallowing threshold, and even masticatory behavior. Two of them stated that the effect was reversible by giving dental treatment. This scoping review concludes a negative effect of caries on the children's chewing ability.

Oral functioning after open versus closed treatment of unilateral condylar neck or base fractures: A two-centre controlled clinical trial

BACKGROUND

Oral functioning and rehabilitation in patients after condylar trauma can be measured by objective functional outcomes and patient-reported outcomes. The similarities or differences between these outcomes may contribute to the decision if open treatment (OT) or closed treatment (CT) will obtain the most advantageous results.

OBJECTIVES

The aim of this study was to compare OT versus CT for unilateral condylar mandibular neck or base fractures in a two-centre controlled clinical trial by objective functional outcomes and patient-reported outcomes measured at 6 weeks and 6 months follow-up. Additionally, these outcomes were compared within each group.

METHODS

Patients were enrolled between January 2017 and November 2019. In one centre, patients received OT by extra-oral open reduction and internal fixation. In another centre, patients received CT by maxillomandibular fixation. Objective measurements included the mixing ability test (MAT) and mandibular active range of motion (ROM). Patient-reported outcomes included the mandibular function impairment questionnaire (MFIQ) and visual analogue scale (VAS) for pain. Independent t-tests and Mann-Whitney U-tests were used to determine differences between the treatment groups at 6 weeks and 6 months follow-up. Paired t-tests and Wilcoxon signed rank tests were used to determine differences within each group.

RESULTS

Thirty-three patients were enrolled. No differences were found between the groups treated with OT or CT for MAT, ROM, MFIQ and VAS. Both groups showed functional improvement.

CONCLUSION

Good objective functional outcomes and patient-reported outcomes were achieved with both OT and CT in patients with unilateral condylar mandibular neck or base fractures.

Primary maxillary sinus carcinosarcoma with multidisciplinary management: a case report with 4 years follow-up and literature review

BACKGROUND

Primary maxillary sinus carcinosarcoma (CS) is an extremely rare malignant tumor characterized by biphasic histologic components, lack of standardized treatment, high recurrence rate, and poor prognosis. This paper presents a case of primary maxillary sinus CS and its treatment.

CASE PRESENTATION

A 39-year-old female patient complained of right facial pain and maxillary teeth numbness on March 21, 2018. Computed tomography examination revealed a malignant mass with osteolytic destruction. Preoperative biopsy suggested sarcomatoid carcinoma or CS. A total right maxillectomy under general anesthesia was performed on April 12, 2018. The final staging was T3N0M0 (ACJJ 2019). Postoperative radiotherapy and chemotherapy were performed. On May 26, 2018, the patient received the first cycle of doxorubicin plus ifosfamide. Two days before radiotherapy, the patient received an intra-oral prosthesis. From June 20, 2018, to August 22, 2018, the patient received concurrent chemoradiotherapy: radiotherapy (60 Gy in 30 fractions) and the second cycle of doxorubicin. Then, the patient received four cycles of doxorubicin plus ifosfamide. The patient was followed for 39 months with no evidence of disease.

CONCLUSION

Using multidisciplinary therapy, clinical-stage T3N0M0 (ACJJ 2019) maxillary sinus CS may achieve a good prognosis.

EVALUATION OF EFFICIENCY OF CHEWING IN PATIENTS WITH ONCOPATHOLOGY OF THE ORAL CAVITY

OBJECTIVE

The aim: The aim of this work is assessment of masticatory efficacy in patients with oral tumors with different localization and severity.

PATIENTS AND METHODS

Materials and methods: The analysis of masticatory efficiency in dynamics was carried out with the help of two-color chewing gum in 29 patients with tumors of the tongue, oral mucosa and mandible. The study was performed at the time of hospitalization and on day 7 after surgery.

RESULTS

Results: After surgery, masticatory parameters decreased compared to baseline and did not recover on the 7th day after surgery. In patients diagnosed with stage I-III mandibular cancer, masticatory values are below 0.5 (0.34 ± 0.04; 0.28 ± 0.03; 0.24 ± 0.03), indicating poor food bolus formation (p<0.05).

CONCLUSION

Conclusions: This method is informative for the formation of the food bolus, which takes into account not only the presence of teeth, but also the function of the muscles involved in chewing. The extent of soft tissue defects plays a more important role in chewing than the presence of dentition and jaw defects. The presence of even 8-10 teeth on the upper and lower jaws may be sufficient for satisfactory grinding and chewing, with a mixed fraction of up to 0.75.

Chemosensory dysfunction in primary Sjögren's syndrome: a topical review

Primary Sjögren's syndrome is an autoimmune exocrinopathy related to lymphocytic infiltration of the exocrine glandular epithelia (such as salivary, lacrimal, nasal, and sebaceous glands or vaginal mucosa) with systemic manifestations of an immuno-inflammatory nature, and not associated with any other systemic disease. It is characterized by severe dryness (Sicca syndrome), particularly in mouth and eyes, with potential strong impact on quality of life and could increase the risk of depression in Sjögren's patient. To date, the impairment of taste and olfactory functions related to Sjögren syndrome remains poorly assessed; so is the trigeminal functions which remain sparsely studied in patients with Sjögren disease. However, other factors can also modify chemosensory functions (olfactory or gustatory sensations and trigeminal nerves), in particular the reduction of the masticatory coefficient or halitosis, due to oral saliva flow decrease, and poor dental condition, which are often present in Sjögren patients. Of the 12 articles evaluated after a 22-year literature search of this review, chemosensory disorders (including taste, smell, and trigeminal impairments) are described and evaluated in pSS patients, with mainly poorer performance compared to healthy controls. Diagnostic and therapeutic (including rehabilitation) approaches of chemosensory disorders in pSS are discussed in this review. Clinician should be more attentive to taste as well as olfacto-trigeminal disorders in primary Sjögren's disease, if possible at the earlier stage, in order to take the best care of Sjögren's patients. This review also highlights some lack in knowledge on pSS chemosensory disorders that should provide new research perspectives. Key Points •Chemosensory functions (including taste, smell, and trigeminal functions) are altered in patients with primary Sjögren's syndrome (pSS) due to dryness of the mouth and the nose. •The trigeminal nerve which interacts with olfactory and gustatory nerves contributes to olfactory and taste perception but remains little studied to date. •Chemosensory function should be considered in the daily clinical assessment of patients with pSS. •Chemosensory function treatment is not standardized yet, however symptomatic treatment of Sjögren syndrome-associated dryness transiently would improve taste and smell, and olfactory or gustatory rehabilitation in pSS patients would be useful.

Long-term masticatory performance and ability following closed treatment for unilateral mandibular condylar neck or base fractures: a cross-sectional study

PURPOSE

The aim of this study was to find explanatory variables for objective and patient-reported long-term masticatory functioning in patients treated with maxillomandibular fixation for unilateral condylar neck or base fractures. These outcomes were compared to healthy control subjects.

METHODS

Patients treated between 1996 and 2013 were enrolled in the study. Objective measurements included the mixing ability test (MAT) for masticatory performance, and range of motion of the mandible. Patient-reported measurements included the mandibular function impairment questionnaire (MFIQ) for masticatory ability, and the visual analogue scale for pain. Healthy subjects were recruited between October 2018 and January 2019, and performed the MAT and MFIQ.

RESULTS

Twenty-one patients and 30 healthy subjects were included. The average follow-up period was 11.67 years. In adjusted regression analysis, the amount of occlusal units (OU) was associated with the MAT (P = 0.020; R² = 0.253) and MFIQ (P = 0.001, R² = 0.454). The MAT outcome was similar in both groups when correcting for OU (P = 0.001; R² = 0.201). The MFIQ was inferior in the patient group (P = 0.001).

CONCLUSION

Long-term masticatory performance was similar in patients with a history of condylar neck or base fracture and healthy subjects; however, masticatory ability was inferior in patients compared to healthy subjects.

Masticatory performance in patients with jaw muscle pain: A case control study

Introduction

Masticatory function is often impaired in patients with painful temporomandibular disorders (TMD) therefore more detailed studies on comminution and mixing ability are warranted in well-defined TMD patients with chronic myalgia. Moreover, there is a need to explore the correlation between any changes in perceived pain or fatigue in such patients and the masticatory function.

Materials and methods

Self-assessments using questionnaires regarding pain, oral health, jaw function, masticatory ability, fear of movement and psychosocial signs were answered by all the participants. A series of chewing tasks involving viscoelastic food and two-colored gum was performed. Optical imaging and analyzing was conducted. Bite force as well as characteristics of pain and fatigue were assessed.

Results

In patients, the fragmented soft candy particles were less in number and had larger median of area and minimum Feret's diameter after standardized chewing compared to healthy individuals (P = 0.02). Surprisingly, the two-colored Hue-Check gum was less mixed by the healthy controls since they displayed a greater variance of the hue (P = 0.04). There were significant differences between the patients and the healthy controls in the self-assessed masticatory ability mainly regarding pain-related variables.

Conclusions

Objectively, TMD patients with chronic myalgia exhibited an impaired masticatory performance with less efficiency in comminuting soft viscoelastic food compared to the pain-free healthy control group. There was an agreement between the patients' self-assessed masticatory ability and the efficiency of their masticatory function.

Assessment of masticatory efficiency based on glucose concentration in orthodontic patients: A methodological study

BACKGROUND

Treatment for malocclusion can cause discomfort and pain in the teeth and periodontium, which may impair masticatory efficiency. The glucose concentration method is widely used to assess masticatory efficiency for its convenience in the clinical situation, although its validity has not been shown.

OBJECTIVES

The aims were to determine the validity of the glucose concentration method and investigate if this method can be applicable to orthodontic patients with braces.

METHOD

Sixteen healthy individuals (7 men, 9 women, and 26 ± 5 years old) and 16 patients with malocclusions needing orthodontic treatment (5 men, 11 women, and 26 ± 4 years old) participated. Glucose concentration was measured after 5-, 10-, and 15-s mastication of gummy jelly and compared to Hue values obtained from the color-changing gum method (reference method). In addition, all participants were asked to fill out the Oral Health Impact Profile questionnaire (OHIP) to assess differences in perception related to the mouth before and after the placement of braces.

RESULTS

Glucose concentrations were strongly correlated to measures of the two-color chewing gum methods (R2  = 0.965). Both the glucose extraction and chewing gum hue value were the smallest for 5 s chewing cycles and increased as the number of chewing strokes increased for the 15 s chewing cycles. (Hue: R² = 0.510, p < 0.001; glucose: R² = 0.711, p < 0.001) Masticatory efficiency assessed by both methods was significantly lower in orthodontic patients compared to controls (p < 0.05), even though it was not affected by bonding (p > 0.09). In addition, OHIP scores in physical pain dimension and psychological disability were higher in orthodontic patients than in the control group (p < 0.005).

CONCLUSION

Measurement of glucose concentration was confirmed as a reliable and convenient method for assessing masticatory efficiency. Furthermore, it appears that this method is applicable to patients with braces whose perception in the oral cavity could change.

Associations between self-reported masticatory dysfunction and frailty: A systematic review and meta-analysis

BACKGROUND

Oral health is a key factor of overall health and closely associated with well-being and quality of life. Mastication is one the most important oral functions and may deteriorate with aging. Evidence on association between masticatory dysfunction and frailty in the literature is scarce and not coherent.

METHODS

A search strategy was developed to conduct a systematic review of the literature in PubMed, CINAHL, and AMED in accordance with the PRISMA 2020 guidelines. We searched for studies published in 2000 or later that examined associations between self-reported masticatory dysfunction and frailty risk. The reference lists of the relevant articles were reviewed for additional studies. We calculated pooled odds ratios (OR) of association between self-reported masticatory dysfunction and the risk of frailty by fixed-effects meta-analysis. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess risk of bias. Publication bias was assessed by visually inspecting a funnel plot.

RESULTS

A total of 285 studies were identified by the literature search. Among 5 studies selected for this review, 4 cross-sectional studies including a total of 7425 individuals were used for meta-analysis. The pooled results by a fixed-effects model showed that there was a significant association between self-reported masticatory dysfunction and frailty risk (pooled OR = 1.83, 95%CI = 1.55-2.18, p<0.00001). There was no evidence of publication bias observed.

CONCLUSIONS

This systematic review and meta-analysis highlighted pooled cross-sectional evidence that community-dwelling older people who report masticatory dysfunction are significantly more likely to be frail than those who do not. The limitations of this study are: inclusion of only cross-sectional studies, no gold standard to measure masticatory functions, self-reported information on masticatory function, and the limited number of included studies. More longitudinal studies are warranted for further understanding of the causal pathways and elucidate underlying mechanisms. Registration: PROSPERO CRD42021277173.

The Relation between Masticatory Function and Nutrition in Older Individuals, Dependent on Supportive Care for Daily Living

Introduction: Associations between masticatory function and nutritional status have been suggested. Masticatory function can be divided into two subdomains, the objective capacity of an individual to mix solid food and the individual’s subjectively assessed ability to masticate solid food. Aim: The aims of this study were to assess the relationship between these subdomains and nutritional variables in older, care-dependent individuals. Materials and methods: From a group of 355 individuals with care dependency and functional limitations, individuals aged 60 and older were selected. By home visits, the subjects underwent an oral examination and answered chewing related questions. Nutritional status was assessed using the Mini Nutritional Assessment. A total of 196 individuals met the age requirement of 60 years or older. Of these, 86 subjects were able to answer the questions. Results: We could not find any concluding significant associations between the subdomains of masticatory function or the nutritional variables. Conclusions: The absence of associations could be explained by the lack of standardized and validated methods to assess masticatory function and they possibly reflect varying underlying constructs. Self-reported questionnaires seem less useful among older and care-dependent individuals, while an objective clinical measurement will be needed when evaluating masticatory function.

Effect of frozen storage on preservation of a silicone-based test food material

Aim: This study aimed to evaluate the effect of frozen storage on the physical properties of a silicone-based test food material, highly used to evaluate the masticatory performance in research settings. Methods: A total of 1,666 silicone cubes of Optosil Comfort® with 5.6-mm edges were shaped and stored at -18°C. The cubes were subsequently tested for flexural strength (maximum force, displacement, stress, and strain) before breaking (n = 136), changes in weight and size (n = 170), and masticatory performance (n = 1360) at eight timepoints: immediately after cube preparation (baseline, no freezing), and 1, 2, 3 and 4 weeks, and 2, 4 and 6 months after frozen storage. The cubes were thawed 8 h before each assessment. Results: The maximum force, stress, maximum displacement, and deformation values for the cubes were not affected by freezing (P > 0.05). At all of the time points, the cubes exhibited similar weight (P = 0.366) and size (identical values). The masticatory performance for the cubes also showed no differences from baseline through 6 months (P = 0.061). Conclusion: Freezing Optosil Comfort® silicone cubes did not alter the physical and mechanical properties of the material, being suitable to optimize the assessment of masticatory parameters for research purposes.

Study of occlusal acoustic parameters in assessing masticatory performance

Background

Previous masticatory studies have focused on a variety of measurements of foods and boluses or kinematic parameters and sound during mastication. To date, the masticatory sound research of has been limited due to the difficulties of sound collection and accurate analysis. Therefore, significant progress in masticatory sound has not been made. Meanwhile, the correlation between acoustic parameters and mastication performance remains unclear. For the purpose of exploring the acoustic parameters in measuring mastication performance, the bone-conduction techniques and sound analysis were used, and a statistical analysis of acoustic and occlusal parameters were conducted.

Methods

The gnathosonic and chewing sounds of fifty-six volunteers with healthy dentate were recorded by a bone-conduction microphone and further analyzed by Praat 5.4.04 when intercuspally occluding natural foods (peanuts) were consumed. The granulometry of the expectorated boluses from the peanuts was characterized by the median particle size of the whole chewing sequence (D50^a) and the median particle size during the fixed chewing strokes (D50^b). The chewing time of the whole chewing sequence (CT^a), the chewing time of the fixed chewing strokes (CT^b), the chewing cycles (CC), and the chewing frequency (CF) were recorded and analyzed by the acoustic software. The acoustic parameters, including gnathosonic pitch, gnathosonic intensity, mastication sound pitch of the whole chewing sequence (MP^a), mastication sound pitch of the fixed chewing strokes (MP^b), mastication sound intensity of the whole chewing sequence (MI^a) and mastication sound intensity of the fixed chewing strokes (MI^b), were analyzed. Independent sample t-test, Spearman and Pearson correlation analyses were used where applicable.

Results

Significant difference in parameters CC, MI^a, CF and D50^a were found by sex (t-test, p < 0.01). The masticatory degree of the test foods was higher in women (CC, 24.25 ± 5.23; CF, 1.70 ± 0.21 s⁻¹; D50^a, 1655.07 ± 346.21 μm) than in men (CC, 18.14 ± 6.38; CF, 1.48 ± 0.18 s⁻¹; D50^a, 2159.21 ± 441.26 μm). In the whole chewing sequence study, a highly negative correlation was found between MI^a and D50^a, and a highly positive correlation was found between MI^a and CF (r =  − 0.94, r = 0.82, respectively, p < 0.01). No significant correlation was found between the remaining acoustic parameters and mastication parameters. In the fixed chewing strokes study, a highly negative correlation was found between MI^b and D50^b (r =  − 0.85, p < 0.01). There was no significant correlation between the rest of the acoustic parameters and the mastication parameters.

Conclusions

Mastication sound intensity may be a valuable indicator for assessing mastication. Acoustic analysis can provide a more convenient and quick method of assessing mastication performance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-02018-9.

Systematization of Degrees of Complexity and Objectification of Clinical Assessment of Dysphagia of Oral and Oropharyngeal Stages of Swallowing

Aim: Global monitoring of the incidence shows that oral and pharyngeal cancer is one of the most common cancers in the world. Treatment of such patients, regardless of its type (surgical, radiation, chemotherapy) is quite traumatic, which leads to damage to surrounding tissues, disruption of their functions and before swallowing. Objectification of the severity of functional disorders is difficult in both the first and second phases of swallowing. There is also no systematization of severity, which could be used in the clinic in such patients. The aim of the work was to select and evaluate methods for diagnosing swallowing disorders and systematization of oral and oropharyngeal dysphagia. Materials and Methods: The study included 36 patients aged 38-55 years (men) who were treated in the Department of Head and Neck Tumors „Podolsk Regional Oncology Center” with malignant tumors of the tongue, bottom of the mouth and oropharynx stage I-III. All patients had problems with chewing and swallowing. A comprehensive method of assessing the effectiveness of chewing and ultrasound examination of the act of swallowing, the presence of the pain component on the visual-analog scale (VAS) at the time of hospitalization and in the postoperative period for 10 days. Results: Clinical and ultrasound studies have shown a reduction in muscle contraction in all patients, regardless of the location of the process. Changes were observed depending on the clinical course of the disease, the prevalence of the tumor and the volume of the muscles being incised. There was a tendency that patients who could not mix and form the food bolus were also unable to take a normal sip. These manipulations were accompanied by varying intensity of pain. Based on the obtained data, groups of patients by severity and their systematization were formed. Conclusions: The systematization of oral and oropharyngeal dysphagia on the basis of objective indicators is proposed (masticatory efficiency – masticatory test, ultrasound examination). To assess the first phase of swallowing, a set of studies with three methods is recommended: 1 – chewing test; 2 – visual-analog scale of pain; 3 – ultrasound examination. To assess the second phase of swallowing – two methods: 1 – visual-analog scale of pain; 2 – ultrasound examination. The transfer of the patient from the tube feeding to the usual was carried out on the basis of the obtained objective indicators, taking into account subjective data as auxiliary.

Patient-reported outcome measures for masticatory function in adults: a systematic review

Objective

The aim of this systematic review was to critically evaluate the Patient-Reported Outcome Measures (PROMs) for masticatory function in adults.

Methods

Five electronic databases (Medline, Embase, Web of Science Core Collection, CINAHL Plus and APA PsycINFO) were searched up to March 2021. Studies reporting development or validation of PROMs for masticatory function on adults were identified. Methodological quality of the included studies was evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) risk of bias checklist. Psychometric properties of the PROM in each included study were rated against the criteria for good measurement properties based on the COSMIN guideline.

Results

Twenty-three studies investigating 19 PROMs were included. Methodological qualities of these studies were diverse. Four types of PROMs were identified: questions using food items to assess masticatory function (13 PROMs), questions on chewing problems (3 PROMs), questions using both food items and chewing problems (2 PROMs) and a global question (1 PROM). Only a few of these PROMs, namely chewing function questionnaire-Chinese, Croatian or Albanian, food intake questionnaire-Japanese, new food intake questionnaire-Japanese, screening for masticatory disorders in older adults and perceived difficulty of chewing-Tanzania demonstrated high or moderate level of evidence in several psychometric properties.

Conclusions

Currently, there is no PROM for masticatory function in adults with high-level evidence for all psychometric properties. There are variations in the psychometric properties among the different reported PROMs.

Trial Registration PROSPERO (CRD42020171591).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01949-7.

Comparing Masticatory Performance of Maxillary Mini Dental Implant Overdentures, Complete Removable Dentures and Dentate Subjects

Background: Mini dental implant (MDI) overdenture rehabilitation for the edentulous maxilla is a valuable, less invasive and affordable treatment alternative for complete removable dentures (CRD). However, comparative quantification of masticatory performance in different oral conditions are scarce. Purpose: This study compares objective masticatory performance of dentate groups, maxillary CRD and MDI overdentures and subjective masticatory performance in maxillary CRD and MDI overdentures. Materials and Methods: Four groups were defined, age 20+ dentate dental students (DS), age 50+ complete dentate subjects (DP), age 50+ maxillary CRD or MDI overdentures/dentate mandible. Objective masticatory performance was evaluated by measuring circular Variance of Hue (VOH) or the mixture degree of two-color chewing gum (Hue-check View Gum^® Test). Additionally, subjective masticatory comparison was investigated in the CRD and MDI groups, with a visual analogue scale (VAS) for different food consistencies and the Oral Health Related Quality of Life (OHRQL) OHIP-14 questionnaire. Results: The mean VOH was 0.11 (SD 0.50, range 0.05–0.27) for the dentate dental 20+ students, 0.13 (SD 0.08, range 0.03–0.31) for the 50+ dentate group (p = 0.774), 0.41 (SD 0.41, range 0.14–0.76) for the CRD group and 0.39 (SD 0.18, range 0.07–0.76) for the MDI group (p = 0.725). Based on the VAS scores, no improvement was found between the CRD and the MDI overdenture group (p > 0.050). The mean OHIP-14 total score was 12.10 (SD 15.87, range 0–56) for CRD, while the MDI group (p = 0.039) saw a significant improvement to 2.85 (SD 2.85, range 0–15). Conclusion: Comparable results in objective masticatory performance were registered in dentate 20+ and 50+ subjects with a remarkable inferior outcome for the CRD and MDI group. Compared to CRD, MDI overdentures revealed no substantial improvement in subjective and objective masticatory performance. However, for MDI a significant increase in OHRQL was apparent.

Reliability and validity of a new colour-changing test food with an acid-base reaction for the clinical assessment of masticatory performance

The aim of this study was to determine the reliability and validity of a new test food for the clinical assessment of masticatory performance. The test food had two overlapping acidic/basic halves. Ten dentate subjects chewed one unit for 10-100 cycles. One subject chewed ten units for the same number of cycles. Differences in the L*, a* and b* colour axes were determined before and after chewing by ANOVA. Colour guides were created based on the values of these axes and matched with the number of cycles. The reliability of the guides was evaluated using 30 images, where three examiners indicated the number of cycles in which the colour closest to that of a chewed material was found. The data were contrasted with the real values of the guides to determine the validity (Kappa coefficients). The equivalence of the guides with the median particle size (X₅₀) was determined using equidimensional curves. The test food progressively changed from green to pink during chewing. As the number of cycles increased, the a* values increased and the b* values decreased (p < 0.05). Overall, the guides showed a Kappa value >0.8 for the intra-examiner and inter-examiner reliability and the validity comparisons. The a* and X₅₀ values were inversely proportional to each other, and the b* values showed a direct relationship with the X₅₀ values. The L* values did not show correspondence. The new test food showed high reliability and validity for the assessment of masticatory performance through clinical colour guides matched with the number of cycles and X₅₀.

Masticatory Ability for a Single Implant Mandibular Overdenture Retained by Two Different Attachments: A Randomized Controlled Trial

Objective

The aim of this randomized clinical trial was to compare the masticatory ability subjectively between ball and Cendres+Métaux Locator (CM-LOC) attachment for a single implant retained mandibular overdenture throughout a 24-month follow-up period.

Materials and Methods

Eighty completely edentulous patients were recruited. All patients received new complete dentures, and masticatory ability was recorded using a questionnaire (baseline record). All patients received a single implant in the midline of the completely edentulous mandible. After 3-month healing period, patients were randomized using sealed envelopes into two groups: ball or CM-LOC attachment. The same masticatory ability questionnaire was used to record masticatory ability for both groups after 2 weeks of pickup and 3-, 6-, 9-, 12-, and 24-month follow-up. Comparison between the study groups was done using Mann–Whitney U test for independent samples. Two-sided P values less than 0.05 were considered statistically significant.

Results

The mean masticatory scores improved for both attachments, with no statistically significant difference between them throughout the 24-month follow-up. The CM-LOC attachment group showed a greater improvement change in masticatory ability after 6- and 12-month follow-up (−12.47 ± 12.006, −11.46 ± 14.625; P=0.826), while the ball attachment group showed a slight improvement after the 24-month follow-up (−11.72 ± 12.368, −10.88 ± 11.963; P=0.778).

Conclusion

Single implant retained mandibular overdenture improved masticatory ability subjectively with no significant difference between both attachments used although the ball attachment showed better masticatory ability scores after 24-month follow-up.

Factors associated with edentulous patients' willingness about implant-supported complete denture: a multivariate analysis

OBJECTIVE

The aim of this study was to evaluate the factors influencing edentulous patients' willingness about mandibular implant-supported complete denture.

MATERIALS AND METHODS

A cross-sectional study was carried out with 117 bimaxillary edentulous patients wearing removable complete dentures (CDs). Patients were assessed concerning denture-related items (number of previous mandibular CDs, previous denture wearing period, dentures maker professional, and regular wearing of previous mandibular dentures) and individual-related aspects, such as mandibular edentulousness period, mandibular bone height, and willingness to the use of mandibular implant-supported complete denture. Masticatory performance was evaluated by the median particle diameter. Mandibular bone height and satisfaction were assessed using a validated method. The Chi-square test was used for data analysis and prevalence ratios were adjusted by using multivariate Poisson regression, both with 95% confidence interval.

RESULTS

A total of 78 participants (66.7%) were interested in mandibular implant-supported overdenture (mean age 65.33 ± 9.49). Masticatory performance was not influenced by choosing mandibular implant-supported complete denture. The preference about mandibular implant-supported complete denture was correlated with longer mandibular complete denture experience (p = 0.021) and it was significantly associated with dissatisfaction about retention (p = 0.005).

CONCLUSION

Previous experience with mandibular complete dentures and dissatisfaction about retention influence the willingness about mandibular implant-supported overdenture.

CLINICAL RELEVANCE

Many factors are associated with rehabilitation preferences for edentulous patients and mandibular implant-supported complete denture is one of the available alternatives. Therefore, this study has demonstrated the factors influencing the decision to replace a mandibular conventional complete denture by dental implant treatment based on patient's outcomes. Such finding may be considered as a relevant aspect towards shared decision-making for prosthodontic rehabilitation of edentulous patients.

Mastication, swallowing, and salivary flow in patients with head and neck cancer: objective tests versus patient-reported outcomes

Purpose

Before and after treatment for head and neck cancer (HNC), many patients have problems with mastication, swallowing, and salivary flow. The aim of this study was to investigate the association between objective test outcomes of mastication, swallowing, and salivary flow versus patient-reported outcomes (PROs) measuring mastication-, swallowing-, and salivary flow–related quality of life.

Methods

Data of the prospective cohort “Netherlands Quality of Life and Biomedical Cohort Study” was used as collected before treatment, and 3 and 6 months after treatment. Spearman’s rho was used to test the association between objective test outcomes of the mixing ability test (MAT) for masticatory performance, the water-swallowing test (WST) for swallowing performance, and the salivary flow test versus PROs (subscales of the EORTC QLQ-H&N35, Swallow Quality of Life questionnaire (SWAL-QoL-NL) and Groningen Radiation-Induced Xerostomia (GRIX)).

Results

Data of 142 patients were used, and in total, 285 measurements were performed. No significant correlations were found between the MAT or WST and subscales of the EORTC QLQ-H&N35. Significant but weak correlations were found between the MAT or WST and 4 subscales of the SWAL-QoL-NL. Weak to moderate correlations were found between the salivary flow test and GRIX at 3 and 6 months after treatment, with the highest correlation between salivary flow and xerostomia during the day (Spearman’s rho =  − 0.441, p = 0.001).

Conclusion

The association between objective test outcomes and PROs is weak, indicating that these outcome measures provide different information about masticatory performance, swallowing, and salivary flow in patients with HNC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-021-06368-6.

A High Masticatory Muscle Tone Predicts the Risk of Malnutrition and Frailty in Inpatient Older Adults: A Cross-Sectional Study

INTRODUCTION

The prevalence of malnutrition among inpatient older adults is as high as 20∼50%. Masticatory performance is known to affect the nutritional status of individuals. However, an objective measurement to reflect the real status of masticatory muscle performance is lacking at the bedside.

METHODS

This pilot study analyzed the masticatory performance using surface electromyography (sEMG) of masticatory muscles that measures both muscle strength and muscle tone at the bedside. The nutritional status was measured using the Mini Nutritional Assessment tool. The handgrip strength was measured using a hand dynamometer. The statistical data were analyzed using SPSS 25 software.

RESULTS

The data revealed that female inpatient older adults more frequently had substandard handgrip strength (p = 0.028), an at-risk and poor nutritional status (p = 0.005), and a higher masseter muscle tone (p = 0.024). Inpatient older adults with an at-risk and poor nutritional status had an older age (p = 0.016), lower handgrip strength (p = 0.001), and higher average masseter muscle tone (p = 0.01). A high masseter muscle tone predicted the risk of having an at-risk and poor nutritional status. The at-risk or poor nutritional status predicted having a substandard handgrip strength by 5-fold.

CONCLUSIONS

A high masticatory muscle tone predicts malnutrition and frailty. Medical professionals should combat masticatory dysfunction-induced malnutrition by detecting masticatory muscle performance using sEMG and referring patients to dental professionals. Additionally, encouraging inpatient older adults to perform oral motor exercise is recommended.

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.

A new masticatory performance scale to integrate food biting, comminution and mixing ability in removable partial denture wearers

BACKGROUND

The existing masticatory performance (MP) tests cannot comprehensively evaluate objective masticatory function.

OBJECTIVES

We aimed to examine the construct validity and responsiveness and determine the clinically minimum important difference (MID) and related factors of a newly developed MP scale to integrate food biting, comminution and mixing ability in patients with removable partial dentures (RPDs).

METHODS

Masticatory performance tests using gummy jelly, peanuts and colour-changeable gum were performed before and 3 months after RPD treatment in 248 partially dentate patients. A 10-point ordinal subscale was created for each MP test based on the distributions of MP values, and the three subscales were integrated into a single scale (iMP scale). We analysed the correlations between MP values and iMP scores and determined the effect size for RPD treatments and the MID on the basis of patient perception of chewing ability.

RESULTS

iMP scores exhibited moderate correlations with the three MP values (|ρ| = 0.73-0.79, p < .001) and with the change scores (|ρ| =0.61-0.64, p < .001). The mean iMP score significantly increased after RPD treatment (p < .001), and the effect size was 0.35. Of the 248 patients, 55 (22%) reported a slight improvement in chewing ability with a mean iMP score change of 2.1 points. Sex and the number of missing teeth were significantly associated with iMP scores (p < .05).

CONCLUSIONS

The iMP scale comprehensively evaluated objective masticatory function, including food biting, comminution and mixing ability in RPD wearers, and an increase of two points on the iMP scale was considered to be the MID in RPD treatments.

Responsiveness of methods to evaluate objective masticatory function in removable partial denture treatments

PURPOSE

The aim of this study was to examine the responsiveness of chewing tests after removable partial denture (RPD) treatment in this prospective cohort study.

METHODS

Pre- and post-RPD treatment, objective masticatory function was evaluated in 248 patients via chewing tests involving peanuts, a gummy jelly, and a color-changeable gum. A statistical comparison was performed between the pre- and post-treatment scores, and the standardized response mean (SRM) was determined as the treatment effect size (ES).

RESULTS

After RPD treatment, the median particle size in the sieving method using peanuts significantly decreased, and the glucose concentration in the gummy jelly method significantly increased (P < 0.001). The ESs of the sieving and gummy jelly methods were larger (|SRM| = 0.3-0.4) than that of the gum method (|SRM| = 0.1). In the subgroup analysis, the sieving and gummy jelly methods resulted in a broader effective range (|SRM| ≥ 0.3) than the gum method. In patients without pre-treatment dentures, the ES was medium in the sieving method (|SRM| = 0.6) and weak in the gummy jelly and gum methods (|SRM| = 0.3-0.4). The pre-treatment level of masticatory function was significantly correlated with ES (ρ = 0.93, P < 0.001).

CONCLUSIONS

These results suggest that the sieving and gummy jelly methods are more responsive than the gum method for RPD treatment and that the pre-treatment scores affect the responsiveness.

Responsiveness of methods to evaluate chewing ability after removable partial denture treatments

BACKGROUND

The ability of an instrument to detect a clinically important change in patient-reported outcomes following prosthetic treatment is critical for its use in clinical practice and research settings.

OBJECTIVES

This study aimed to examine the responsiveness of instruments in evaluating patient perception of chewing ability after removable partial denture (RPD) treatment in a prospective cohort.

METHODS

A single 100-mm visual analogue scale (VAS), 20-item food intake questionnaire (FIQ) and 6-point chewing difficulty scale (CDS) were administered to 248 partially edentulous patients to evaluate chewing ability pre- and post-RPD treatment. We conducted a statistical comparison between the pre- and post-treatment scores and determined the effect size (r) of RPD treatment for the instruments.

RESULTS

A significant improvement in chewing ability after RPD treatment was identified by VAS and CDS (P < .05), but not by FIQ (P = .16), which identified an improvement after controlling for sex, age, the number of missing teeth and presence/absence of existing removable dentures. The effect size was medium for VAS (r = .54), weak for CDS (r = .14-.17) and absent for FIQ (r = -.09). The increase in r was significantly associated with impaired chewing ability before treatment (ρ = -0.87, P < .001).

CONCLUSIONS

These results suggest that the 100-mm VAS, followed by CDS, is the most responsive instrument to detect an improvement in chewing ability after RPD treatment. Pre-treatment impairment of chewing ability was associated with better responsiveness of the instruments.

Masticatory performance of denture wearers with the use of denture adhesives: A systematic review

STATEMENT OF PROBLEM

Denture adhesives are products used by wearers of removable dental prosthesis; however, systematic reviews on their influence on masticatory performance are lacking.

PURPOSE

The purpose of this systematic review was to evaluate the efficiency of denture adhesives in improving the masticatory performance of users of complete dentures (CD).

MATERIAL AND METHODS

This systematic review was organized from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, and the methods were registered on the international prospective register of systematic reviews (PROSPERO-CRD42020187385). The focus question was as follows: "Does the use of denture adhesives improve the masticatory performance of patients with removable dental prostheses?" The databases PubMed/MEDLINE, Scopus, Web of Science, and Cochrane Library were used to extract information.

RESULTS

The search yielded 1338 articles, of which 6 met the inclusion criteria and were selected. All included studies were crossover randomized controlled trials including bimaxillary edentulous individuals. Masticatory performance was evaluated by using a comminution and sieve method.

CONCLUSIONS

Denture adhesives significantly increased the masticatory performance of CD users.

Masticatory ability in older individuals: A qualitative interview study

Aim

To explore older individuals’ experienced masticatory ability and the impact of masticatory ability in daily life.

Material and methods

This study applied an open‐ended exploratory approach using inductive reasoning. The design was inspired by the qualitative method grounded theory. The final sample consisted of twelve older participants. Seven were men, and five were women. The interviews were audio‐recorded and transcribed verbatim. The interviewer successively read the transcribed data and analysed the material in cooperation with the authors.

Results

Three categories developed from the data; Deteriorating oral health and functional loss, Eating habits, Prosthetic rehabilitation and function. A core category named Adaptation emerged. Adaptation describes how individuals successfully could adapt to a decreased function and in spite of this develop a positive view of their masticatory ability.

Discussion

The participants described an experience of gradually deteriorating oral function that had affected their masticatory ability. By adapting to this functional degradation, some of the participants overcame the functional deficiencies. Most participants perceived their masticatory ability to be good, even though their ability to process some food types was described as inadequate.

Conclusion

The participants had experienced deteriorating oral health and function throughout life, and they overcame this through adaptation by adjusting their eating habits. Even though prosthetic treatment might be considered successful by the participant, this does not necessarily improve dietary habits. Future research should therefore focus on how dental treatment can be combined with other interventions, such as dietary counselling and physiotherapy to recover physiological function.

Reliability of the mixing ability test testing masticatory performance in patients with head and neck cancer and healthy controls

Background

Treatment of patients with head and neck cancer can result in disrupted mastication. To measure masticatory performance in people with compromised mastication, the mixing ability test (MAT) was developed.

Objective

In this study, the reliability of the MAT was evaluated in patients with head and neck cancer and healthy controls.

Methods

Thirty‐four patients with head and neck cancer and 42 healthy controls performed the MAT twice on the same day. To assess reliability, the intra‐class correlation coefficient (ICC_2,1), standard error of measurement (SEM), smallest detectable change (SDC) and limits of agreement (LoA) were calculated.

Results

A good (ICC = 0.886) and moderate correlation (ICC = 0.525) were found for patients and healthy controls, respectively. Patients had a worse mixing ability (mean = 19.12, SD = 4.56) in comparison with healthy controls (mean = 16.42, SD = 2.04). The SEM was 0.76 in patients and 1.45 in healthy controls, with a SDC of 2.12 and 4.02, respectively. The LoA was −4.46 to 4.42 in patients and −3.65 to 4.59 in healthy controls.

Conclusion

The MAT has a good reliability in patients with head and neck cancer and a moderate reliability in healthy controls.

Supplied Food Consistency and Oral Functions of Institutionalized Elderly

Background

Maintaining good oral function is one of the goals of dental treatment. The Japanese national insurance system newly introduced the concept of management of oral function according to the life stage. For the application of management of oral functions of the elderly, seven kinds of examination is a must for the diagnosis: xerostomia, oral hygiene status, maximum occlusal pressure, tongue and labium function, tongue pressure, chewing ability, and swallowing function. We analyzed the relationship between oral functions and supplied food consistency.

Methods

Oral functions and supplied food consistency of sixty-nine institutionalized elderly were investigated. There were 13 men and 56 women, and their mean age was 86.23 ± 7.02. Oral functions were measured and evaluated according to the Japanese insurance system. Data were analyzed by item response theory analysis, ROC analysis, and decision analysis.

Results

By the item response theory analysis, tongue pressure and swallowing functions had high discrimination ability. The subjects who had malfunction of the tongue and labium all had processed food. The subjects with difficulty in swallowing, even without malfunction of the tongue and labium, all had processed food.

Conclusion

Supplied food consistency may depend on the oral functions. However, as oral function has some dimension, a systematic evaluation system is necessary to decide the supplied food consistency.

Chewing ability and oral health-related quality of life in frail elders after new complete dentures insertion: A paired controlled clinical trial

AIMS

To compare the effect of new complete dentures (CDs) on self-perceived masticatory ability (MA) and oral health-related quality of life (OHRQoL) in frail and nonfrail elders.

METHODS AND RESULTS

Twenty completely edentulous elders were assigned to two groups: frail and nonfrail (n = 10/each). MA was evaluated using a visual analogue scale. OHRQoL was assessed with the Oral Health Impact Profile (OHIP-Edent). Variables were evaluated with volunteers wearing their old and unsatisfactory CDs. Then, a new set of CDs was manufactured and all outcomes were reassessed 2 months after the insertion. Data were analyzed by repeated measures' analyses of variance and Tukey tests. MA for lettuce and peanuts was improved (P < .05) for the frail group after new CD insertion. Psychological discomfort and handicap OHIP-Edent domain improved (P < .05) for both groups after prosthetic treatment. Before treatment, controls reported greater psychological discomfort than the frail group. Meanwhile, the handicap domain score of frail patients improved to a level similar to that of the nonfrail group after treatment. Regardless of frailty, elders showed better MA scores for most food types after treatment and decreased OHIP-Edent domain values.

CONCLUSION

Self-reported MA and OHRQoL of frail elderly people were greatly improved after new CD use.

Reproducibility and construct validity of the utrecht mixing ability Test to obtain masticatory performance outcome in patients with condylar mandibular fractures

OBJECTIVE

This study assessed the test-retest reproducibility of the Utrecht mixing ability test (MAT) and the construct validity of the MAT in relation to the Mandibular Function Impairment Questionnaire (MFIQ) in patients with mandibular condylar fractures.

MATERIAL AND METHODS

Twenty-six patients treated for a mandibular condylar fracture participated in this clinimetric study; all patients performed the MAT twice. Simultaneously the MFIQ was conducted. Test-retest reliability and construct validity were assessed using the intra-class correlation coefficient (ICC) and Spearman correlation, respectively.

RESULTS

The ICC of the MAT was 0.906 (95% CI: 0.801-0.957), which indicates an excellent reliability. A weak correlation of 0.386 (P = .052) between the first MAT and the overall outcome of the MFIQ was found. A significant moderate correlation of 0.401 (P = .042) was found between the retest of the MAT and the overall outcome of the MFIQ. One question on the MFIQ (about yawning) showed a moderate positive correlation of 0.569 (P = .002) and 0.416 (P = .034) for the MAT test and retest, respectively.

CONCLUSION

The MAT is an easy test to use in follow-up of patients. The test-retest reliability of this test is excellent in condylar trauma patients. As the validity of the MAT and the MFIQ could not be confirmed, the MFIQ may be an addition to patient's feedback about the rehabilitation process of their mandibular functioning.