A novel colourimetric technique to assess chewing function using two-coloured specimens: Validation and application

Changes in masticatory performance and bite force after treatment with mandibular overdentures retained by four titanium-zirconium mini implants: One-year randomised clinical trial

OBJECTIVE

This prospective study is part of a randomised clinical trial and reports the changes in masticatory performance (MP) and bite force, and explores their influential factors, 1 year after the provision of mandibular overdentures retained by four titanium-zirconium mini implants.

METHODS

Edentulous patients received conventional complete dentures, followed by placement of four mini implants (Straumann® Mini Implant System) in the anterior mandible and converting the conventional prosthesis into a mandibular overdenture. Treatment protocols were randomised using a 2×2 factorial design combining different surgical (flapped vs. flapless) and loading (immediate vs. delayed) protocols. MP was assessed using a two-colour mixing ability test and a colorimetric analysis to measure the level of colour mixing (Variance of Hue-VoH). Maximum voluntary bite force (MBF) was measured by a digital gnathodynamometer in the posterior and anterior regions. Sex, age, surgical and loading protocols and ridge morphology were tested as independent variables. MP and MBF tests were performed at baseline (pre-treatment) and the 3-, 6- and 12-month after implant loading. Descriptive statistics, independent t-test, and linear mixed-effect model (LMM) regression were used for data analysis.

RESULTS

Seventy-four participants were assessed and 73 completed the 1-year follow-up. Statistically significant improvements in functional parameters were observed in all follow-up periods compared to baseline (p < .001). The flapless protocol was associated with higher improvement in MP at the 3-month follow-up (p = .004), while less resorbed ridges were associated with better MP (p = .038) and higher MBF (p < .001).

CONCLUSION

The mandibular overdenture protocol using four titanium-zirconium mini implants was effective in improving MP and MBF of edentulous patients, compared to pre-treatment values. The findings also suggest that improvements in chewing function and bite force are impacted by clinical factors since better outcomes were observed for flapless surgeries and less resorbed edentulous ridges.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.Gov ID NCT04760457.

Craniosynostosis: orofacial and oral health perspectives with masticatory insights

BACKGROUND

Craniosynostosis (CS), premature fusion of one or more cranial sutures, leads to abnormal skull development, impacting both facial esthetics and oral function. This study aimed to evaluate the specific orofacial and oral health characteristics, including masticatory performance, in Thai patients with CS.

METHODS

A comparative study was conducted with Thai CS patients aged 6-17 years and a control group of healthy individuals with similar age distribution. Assessments included craniofacial morphology, oral health status, and masticatory performance. Intergroup comparisons utilized appropriate statistical tests.

RESULTS

The study included 24 CS patients with a mean age of 10.11 ± 2.98 years and 30 controls. CS patients exhibited a significantly higher prevalence of various oral conditions compared to controls: cleft palate (20.8%), anterior open bite (41.7%), anterior crossbite (54.2%), posterior crossbite (50%), combined anterior-posterior crossbite (45.8%), dental crowding in both maxilla and mandible (50% and 45.8% respectively), congenitally missing teeth (50%), supernumerary teeth (12.5%), and eruption failure (54.2%). Furthermore, CS patients exhibited significantly higher caries prevalence and susceptibility, alongside poorer oral hygiene, compared to controls. Regarding jaw relationships, CS patients exhibited a significantly higher proportion of Angle's Class III malocclusion (50%) compared to the control group, where Class I malocclusion was predominant (50%). Masticatory performance, assessed using the two-color gum mixing ability test, showed significantly higher hue variance in CS patients (0.12 ± 0.07) compared to the control group, indicating reduced chewing performance.

CONCLUSION

This study underscores the significant orofacial and oral health challenges faced by children with CS, including a high prevalence of malocclusions, dental anomalies, elevated caries experience, and compromised masticatory function. These findings emphasize the importance of tailored interventions and comprehensive oral healthcare strategies to address the unique needs of this population and improve their overall quality of life.

[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.

Exploring botulinum toxin's impact on masseter hypertrophy: a randomized, triple-blinded clinical trial

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

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).

The potential causal path between periodontitis stage diagnosis and vegetable consumption is mediated by loss of posterior functional tooth units and masticatory function

AIM

Emerging evidence points to a two-way relationship between periodontitis and dietary choices and, thus, nutrition. This study aimed to assess the potential cause-effect relationship between the periodontitis stage, loss of functional tooth units (FTUs), masticatory function, and intake of different food groups using path analysis.

MATERIALS AND METHODS

A single calibrated examiner determined the periodontitis stage of a consecutive sample of 241 Chinese subjects reporting for tooth replacement. Their masticatory function was quantified by the mixing ability of a two-colour chewing gum. Validated food frequency questionnaires were used to calculate the intake of 33 food group items by an experienced calibrated rater. After verification of assumptions, visual structural equation modeling was performed with Amos 23. The consistency of results and the potential modifying effect of age were assessed in 9043 subjects from the NHANES database.

RESULTS

Highly significant models were constructed using periodontitis stage and age as exogenous factors. Periodontitis stage diagnosis significantly affected the number of posterior FTUs and oral health-related quality of life (OHRQoL, path coefficient [PC] = -0.55 and -0.20, p < .05, respectively). In the model, FTUs also had an independent effect on OHRQoL (PC = 0.23, p < .05). FTUs determined the level of masticatory function (PC = -0.38, p < .05), which in turn affected vegetable intake but not fruit or meat intake (PC = -0.18, p < .0.5, PC = 0.06, NS and PC = 0.11, NS, respectively). The effect of age was significant for vegetable and meat intake and was also correlated with periodontitis stage diagnosis. Analysis of the NHANES database confirmed the negative impact of periodontitis on the number of occluding pairs and vegetable consumption for the 18-44, 45-60 and >60 age groups.

CONCLUSIONS

Periodontitis showed a potential cause-effect pathway affecting vegetable intake across cultures and age groups. The size of the effect is potentially of clinical and public health significance. Additional studies, including intervention trials, are required to test this potential mechanism linking oral health to nutrition.

Influence of masticatory side switch frequency on masticatory mixing ability and sensory perception in adults with healthy dentitions: A randomized crossover trial

STATEMENT OF PROBLEM

The advantages and disadvantages of frequently changing sides while masticating remain unclear.

PURPOSE

The purpose of this clinical study was to determine the effect of varying the frequency of masticatory side switches on masticatory mixing ability and sensory perception in dentate adults.

MATERIAL AND METHODS

This nonblinded, randomized 12-period crossover study, conducted at Barcelona Dental School from January to March 2022, included 36 healthy adults with natural dentitions (median age, 23.5 years; 26 women). Participants were randomly allocated to 12 sequences and performed 12 masticatory assays masticating a 2-colored gum for 40 cycles each using the following masticatory styles as interventions: freestyle, unilateral right, unilateral left, and switching sides 5%, 15%, and 25%. The primary outcome was the mixing ability index (MAI), defined as the standard deviation of the red channel intensity of the masticated gum in the color-histogram plugin of the ImageJ software program. Participants also rated the perceived flavor intensity and salivary flow on a visual analog scale. Data were analyzed by repeated measures analysis of variance (α=.05).

RESULTS

The MAI was similar for all masticatory styles (P=.63). Participants perceived greater flavor intensity (mean difference: 8%, 95% CI: 1% to 15%) and salivary flow (mean difference: 11%, 95% CI: 0% to 21%) with 25% side switching compared with freestyle or unilateral mastication.

CONCLUSIONS

Frequently switching the masticatory side while masticating gum does not alter the mixing ability, but it appears to enhance salivary flow and flavor intensity.

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.

Very old age impacts masticatory performance: a study among sexagenarians to centenarians

OBJECTIVE

This cross-sectional pilot study evaluated the impact of age on masticatory performance among individuals aged 65 to 106 years, as part of the Heidelberg Dental Centenarian Study (HD-100Z) conducted in South-Western Germany.

MATERIALS AND METHODS

A total of 31 centenarians were recruited, alongside 31 individuals each from the age groups 75-99 and 65-74, matched based on sex, prosthetic status, and number of teeth. Masticatory performance was assessed using a two-colored chewing gum test and digital image processing. Multiple linear regression analysis was performed to assess the effect of age, sex, number of teeth, type of prosthesis on the masticatory performance.

RESULTS

Masticatory performance, as measured by the standard deviation of hue in the chewing gum test, decreased significantly in centenarians compared to individuals aged 75-99 years (-0.112, p = 0.037) and those aged 65-74 years (-0.274, p < 0.001). The effects of sex, number of teeth, and type of prosthesis on masticatory performance were not significant associations (p ≥ 0.135).

CONCLUSION

The findings suggest that age may have a significant influence on masticatory performance in the studied age groups, challenging previous notions that aging itself has little impact on masticatory ability. The inclusion of centenarians in the study highlights the need for further investigation into masticatory function in age groups reaching up to 100 years or more.

CLINICAL RELEVANCE

This study contributes to the understanding of how ageing affects oral function, which may guide dental treatment approaches for older individuals, and set the stage for more in-depth investigations in this field in the future.

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.

Chewing efficiency and contact area discrepancies in Angle's class I and II malocclusion: A comparative study

Objective

The study aimed to assess and compare both the chewing efficiency and the contact area between class I and class II of Angle's malocclusions.

Material and methods

A total of 120 individuals aged between 19 and 30 years were examined and were divided into two groups according to Angle's class (Class I and class II). The chewing efficiency was quantified using the ViewGum software and two-colored chewing gum. The contact area was quantified using modeling wax and MATLAB software. All data were collected, then, analyzed using SPSS software 21. Data normality was checked through kurtosis test. Descriptive results were calculated. Matched sample t-tests were used to compare chewing efficiency measurements between right and left sides. Independent t-tests were used to compare chewing efficiency and the contact area between class I and class II of Angle's malocclusions. Linear regression and Pearson correlation were used to assess the correlation between chewing efficiency and the contact area. The significance level was fixed at p = 0.05.

Results

For group 1, the mean hue value on both sides was 0.086 ± 0.058. For group 2, it was 0.095 ± 0.055. The difference between both groups was statistically significant (p = 0.03). For group 1, the mean contact area was 49.91 ± 21.47 mm2. For group 2, it was 51.42 ± 19.76 mm2. The difference was statistically not significant (p = 0.4). The correlation between the contact area and the chewing efficiency in both groups was statistically significant and it was negative (in class I p = 0 and R = -0.616; in class II p = 0.01 and R = -0.408).

Conclusion

The Chewing is better for patients with Angle's Class I malocclusion. The contact area is higher. Larger occlusal contact area leads to higher masticatory efficiency. Further studies should be conducted.

Chewing Function with Efficiency Tests in Subjects Wearing Clear Aligners

This study assessed the masticatory function of participants wearing clear aligners in order to determine whether these devices can be worn even when eating and therefore worn to extend treatment time and boost treatment effectiveness. An intercontrol test was conducted on 20 patients who received Invisalign® treatment. Each participant was instructed to chew two pieces of Hue-Check Gum® chewing gum (one pink and the other blue) in 5, 10, and 20 cycles both with and without aligners. After being removed from the oral cavity, the gum was dried and pressed using a 1 × 50 × 50 mm model that was 3D printed with a transparent layer in between. After being scanned on both sides with a flatbed scanner at 600 dpi, the samples were saved as jpg files and subjected to an optoelectronic examination using ViewGum software. To validate the procedure, a control group from a different institution (University of Bern) was used. A statistical analysis of the data was carried out. The Shapiro-Wilk test was used to confirm the normality of the samples. A one-way ANOVA test, a homogeneity of variance test, and a t-test did not reveal statistically significant differences between the two control groups, thus validating the methodology employed. In summary, clear aligners do not radically change the masticatory function while they are worn. As a result, clinicians can exploit the aligners for chewing to obtain a better fit of the plastic material to the dental surface and to attachments. Treatment times for patients could also be shorter.

Implant-supported prostheses in patients with special needs: A systematic literature review of protocols and outcomes

STATEMENT OF PROBLEM

Implant-supported prostheses for individuals with special needs have been considered high-risk because of the prevalence of poor oral hygiene and parafunction in this population; however, systematic evidence on protocols and outcomes is scarce.

PURPOSE

The purpose of this systematic review was to summarize implant procedures and outcomes for the special needs population.

MATERIAL AND METHODS

A systematic literature review was conducted using PubMed, Embase, and Scopus databases in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodological framework. Data collected included patient information, location and number of implants, surgical and prosthetic procedures, behavior support techniques, postoperative follow-up, complications, and criteria for outcome assessment. Survival rates were pooled for quantitative analysis, and a separate analysis pooling data from groups of special needs patients that present similar risks was undertaken.

RESULTS

The qualitative analysis included 79 studies involving 759 patients and 2269 implants. The quantitative analysis included 65 studies concerning 666 patients with special needs and 1886 implants. The overall weighted implant survival rate was 95.4%, with a mean follow-up duration of 40.7 ±29.5 months.

CONCLUSIONS

In individuals with special needs considered suitable for implant-supported prostheses by their clinician, implant survival rates were similar to those reported in the general population. (J Prosthet Dent xxxx;xxx:xxx-xxx).

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.

Measuring oral health-How can the International Classification of Functioning help?

There is a need for a theoretically informed, contextualized approach to measuring oral health from a multidisciplinary perspective that goes beyond the commonly used clinical indices and sociodental measures. This commentary aims to discuss the potential for the WHO's International Classification of Functioning, Disability and Health (ICF) to provide a model for the development of indicators for oral health. It is suggested that the ICF might provide both a theoretical model and an operational classification for indicators of oral health. The ICF model states that human experience of physical, cognitive and social functioning is universal and, thus, can be described and qualified. Human function is given social and environmental context within the model at both an individual and population level. The ICF can not only capture data regarding oral health and function at the physiological level (e.g. chewing) but also at the social level (e.g. sharing meals). It is able not only to capture aspects of preventive behaviour (e.g. caring for teeth) but also aspects of social facilitation (e.g. economic self-sufficiency) or ability to fulfil a social role (e.g. remunerative employment). It also includes aspects of social environment, such as healthcare services or political, economic and legal systems. Case studies are given as examples of the potential use of the ICF in the oral health domain. Examples are also given of the first steps that have been made towards operationalization of the ICF in data collection and oral health research. The challenges of encompassing such a comprehensive model into a practical oral health measure are discussed.

Subjective and objective evaluation of masticatory function in patients with bimaxillary implant-supported prostheses

BACKGROUND

People perform poorly in masticatory function tests despite well-functioning prostheses. However, it is unclear whether there is an agreement between subjective and objective measures of mastication.

OBJECTIVES

To investigate the association between subjective and objective measures of masticatory function in patients with bimaxillary implant-supported prostheses.

MATERIALS AND METHODS

An experimental group (n = 25, age = 70.6 ± 7.5 years, eight women) with bimaxillary implant-supported fixed prostheses and a control group (n = 25, age = 69.0 ± 5.3, 13 women) with natural dentition were recruited. The participants in the experimental group were included if they had been using the prosthesis for at least a year and had no obvious complaints with their prostheses. The control group was people with natural dentition and without any prostheses or complaints related to the masticatory system. The masticatory function was evaluated objectively with food comminution and mixing ability tests, and subjectively with jaw function limitation scale (JLFS) and oral health impact profile (OHIP).

RESULTS

The experimental group performed poorly in both objective tests (p < .001). However, there was no significant differences between the two groups in total JFLS (p = .114) and OHIP (p = .312) scores. Though, there were certain positive correlations between the food comminution test and JFLS subdomains in the control group, and a positive correlation between food comminution test and specific subdomains of OHIP in the experimental group indicating poor correlation between the subjective and objective measures.

CONCLUSION

Although patients with implant prostheses show poor masticatory performance, there is no agreement in the objective and subjective measures of mastication.

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.

Use of handgrip strength measurement as an alternative for assessing chewing function in people with dementia

Background

Chewing ability and handgrip strength can be independent explanatory factors of physical fitness. The usability of measurement procedures for assessing chewing function in people with dementia seems to be limited. This study aimed to show an association between handgrip strength and chewing function to enable the use of handgrip strength measurement as an alternative for determining chewing parameters in people with dementia. 

Methods

The data analysed here are part of the OrBiD (Oral Health, Bite Force and Dementia) pilot study. A total of 120 participants were assigned to five evaluation groups based on their cognitive abilities using the Mini-Mental State Examination (MMSE). The MMSE groups in this data analysis were “no dementia” (noDem, MMSE 28–30), “mild cognitive impairment” (mCI, MMSE 25–27), and “mild dementia” (mDem, MMSE 18–24). Handgrip strength, maximum occlusal force, and chewing efficiency were measured. 

Results

The Mini-Mental State Examination scores among all participants (n = 71) resulted in a median of 27 and a range of 18–30. An association between maximum handgrip strength and the cognitive impairment of the participants was shown. Nevertheless, the use of handgrip strength measurement as an alternative for determining chewing function was not verified in this study.

Conclusions

The feasibility and reliability of chewing function measurements in people with dementia should be investigated. Existing measurement procedures may need to be adapted or new assessments may need to be developed to be usable in people with dementia.

Trial registration

ClinicalTrials.gov NCT03775772.

Assessment of masticatory efficiency based on glucose concentration in orthodontic patients - a methodological study

INTRODUCTION

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.

OBJECTIVE

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.

DESIGN

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.

Within-patient evaluation of chewing efficiency and maximum bite force of conventional dentures, fixed prostheses, and milled bar overdentures used for All-on-4 implant rehabilitation of atrophied mandibular ridges: A short-term randomized trial

PURPOSE

This crossover study aimed to evaluate chewing efficiency and maximum bite force (BF) of conventional dentures, fixed prostheses, and milled bar overdentures (MO) used for All-on-4 implant rehabilitation of atrophied mandibular ridges.

METHODS

Sixteen edentulous participants with resorbed mandibular ridges received new conventional dentures (CD, control). Four implants were inserted after 3 months in the mandible using the All-on-4 protocol and loaded immediately with acrylic prosthesis. In a crossover manner, each patient had either fixed restoration (FR, 12 occlusal units) or MO (14 occlusal units) randomly in a crossover study design. Chewing efficiency was evaluated using the mixing ability test. The hue deviation (HD) of two-colored gum was calculated after being chewed for 5, 10, 20, 30, and 50 masticatory cycles. Maximum BF was evaluated using a BF device. HD and BF were measured after using CD, FR, and MO prostheses.

RESULTS

For all groups, the highest HD (i.e., the lowest chewing efficiency) was noted with 5 strokes, followed by 10, 20, 30 strokes, and the lowest HD (i.e., the highest chewing efficiency) was noted with 50 strokes. For all number of chewing strokes, CD showed the highest HD, then FR, and MO recorded the lowest HD. The highest BF was observed with MO, then FR, and the lowest BF was noted with CD.

CONCLUSION

Within the limitations of this short-term investigation, both FR and MO used for All-on-4 implant rehabilitation of patients with resorbed mandibular ridges improve masticatory efficiency and maximum BFs compared to CD. However, MO was associated with significantly higher chewing efficiency and maximum BFs than fixed prosthesis.

The Effect of a Masticatory Muscle Training Program on Chewing Efficiency and Bite Force in People with Dementia

Until now, no study has investigated the effects of masticatory muscle training on chewing function in people with dementia. This study aimed to investigate whether physiotherapeutic exercises for the masticatory muscles have an influence on chewing efficiency and bite force in people with dementia. In a clinical trial with stratified randomization subjects were assigned to three groups based on the Mini Mental State Examination (MMSE: group 1—28–30, group 2—25–27, group 3—18–24). Each group was divided into an experimental (ExpG, intervention) and control group (ConG, no intervention). As intervention a Masticatory Muscle Training (MaMuT) (part 1: three physiotherapeutic treatments and daily home exercises, part 2: daily home exercises only) was carried out. Chewing efficiency and bite force were recorded. The MaMuT influenced the masticatory performance regardless of the cognitive state. Bite force increased in ExpG 1 and 2. Without further training, however, the effect disappeared. Chewing efficiency increased in all ExpG. After completion of the training, the ExpG 2 and 3 showed a decrease to initial values. Subjects of ExpG 1 showed a training effect at the final examination, but a tendency toward the initial values was observed. ExpG 3 seemed to benefit most from the physiotherapeutic exercises in terms of improving chewing efficiency by the end of the intervention phase. ExpG 1 showed the greatest gain in bite force. The MaMuT program is a potential method of improving masticatory performance in people with cognitive impairment or dementia when used on a daily basis.

The OrBiD (Oral Health, Bite Force and Dementia) Pilot Study: A Study Protocol for New Approaches to Masticatory Muscle Training and Efficient Recruitment for Longitudinal Studies in People with Dementia

Research with people with dementia is a great challenge in terms of recruitment, study participation and adherence to interventions resulting in less research activity and higher financial, organizational and personnel efforts. As dementia progresses, there is a deterioration in general and oral health and chewing function. Oral treatment options often focus on healthy patients. Interventions for people with dementia are needed. The aims of the paper were to describe the study protocol of the OrBiD (Oral Health, Bite Force and Dementia) pilot study as well as the description of two new methodological approaches. These are (A) an efficient recruitment process of people with dementia, simultaneous double study participation and (B) a novel approach to train the masticatory muscles by using physiotherapy. A novel methodology for the recruitment process (A) and, in particular, for the assignment of subjects to the experimental and control groups was developed and successfully tested. Additionally, a physiotherapy program (B) to train strength and coordination of the masticatory muscles was newly developed with the challenge to ensure that this training could also be carried out with people with cognitive impairments and dementia, if necessary, in cooperation with their relatives or caregivers. This was also successfully implemented. Recommendations for a feasibility assessment of a study involving people with dementia were made considering the organizational effort, the required personnel, structural and financial resources, the required number of subjects and the type of study design. When planning crossed studies, it must be ensured that the content, the interventions or their possible results of the study arms do not influence each other. The overall aim of this paper is to demonstrate the sustainable and efficient feasibility of studies with people with dementia.

Assessment of masticatory function in the differential diagnosis of stage IV periodontitis: A pilot diagnostic accuracy study

BACKGROUND

After diagnosis of periodontitis is made, detection of stage IV cases is critical for appropriate management that may call for interdisciplinary care. This study aims to identify and assess the accuracy of a simple screening approach for practice and surveillance of stage IV periodontitis.

METHODS

Masticatory function assessments by both validated self-reported masticatory dysfunction questionnaire and dual-color chewing gum mixing ability test (index test) were conducted in 214 consecutive patients, followed by a full-mouth periodontal examination. Periodontal diagnosis was based on the 2017 World Workshop classification of periodontal diseases (reference standard). Multivariate logistic regression and area under the receiver operating characteristic curve (AUROC) analyses were performed.

RESULTS

Overall, the individual patient-reported masticatory dysfunction questions showed low to moderate accuracy for predicting Stage IV periodontitis. The objective measures of masticatory function by calculating the variance of hue from the chewing gum test performed better with an AUROC of 0.840. A diagnostic approach based on age, self-report of altered food type intake, and chewing gum test result exhibited excellent performance for predicting Stage IV periodontitis (sensitivity: 89.7%; specificity:76.3%; AUROC:0.912).

CONCLUSIONS

Once the presence of periodontitis has been established, a simple diagnostic approach that does not require specialized workforce, complex or lengthy assessment allows identification of Stage IV periodontitis patients. This is important as these patients require specific case work up and interdisciplinary care pathways. Additional studies are required to validate the findings in multiple populations. This article is protected by copyright. All rights reserved.

Food Intake, Masticatory Function, Tooth Mobility, Loss of Posterior Support and Diminished Quality of Life Are Associated with More Advanced Periodontitis Stage Diagnosis

AIMS

To describe periodontal and functional characteristics of subjects diagnosed with different stages of periodontitis and to associate measures of masticatory function and quality of life with periodontitis stage.

METHODS

This was a cross-sectional study on a convenience sample of 214 subjects with periodontitis seeking oral care in a hospital setting. They received a full mouth intraoral examination including dental and periodontal charting by a single calibrated examiner who also established the periodontitis stage diagnosis. Subjects were assessed using the OHIP-14, a validated masticatory dysfunction questionnaire and a quantitative test based on the ability to mix a dual color chewing gum. Mixing was quantified based on variance of hue (VOH) with a colorimetric software. Descriptive, univariate and multivariate analyses were performed.

RESULTS

Subjects with stage IV periodontitis reported greater impairment of oral health related quality of life, reduced food intake or altered food type intake attributed to difficulties in chewing, objective measures of masticatory dysfunction, tooth loss as well as more advanced periodontal breakdown compared with subjects with stage I-III diagnosis. Quantitative assessment of masticatory function was associated in a multivariate analysis with: i) loss of functional tooth units in the premolar/molar region, presence of hypermobile teeth and severity of periodontal attachment loss; and ii) age, body mass index and periodontitis stage IV and grade C diagnosis.

CONCLUSIONS

Stage IV periodontitis subjects are characterized by a specific set of signs and symptoms of advanced periodontal breakdown and functional impairment which impact on quality of life and masticatory function/food intake choices. Stage IV periodontitis captures a clinical entity with distinct features and treatment needs. This article is protected by copyright. All rights reserved.

Obturator Prosthesis Rehabilitation after Maxillectomy: Functional and Aesthetical Analysis in 25 Patients

The number of patients undergoing a surgical resection of the maxilla for oncological reasons is constantly increasing, the most common complication of which remains the communication between oral and nasal cavities. On the basis of data arising from the literature regarding the treatment options of maxillary oncological post-surgical defects, obturator prosthesis remains the most used worldwide. We studied 25 patients (with at least 1-year follow up) rehabilitated by obturator prosthesis after maxillary resection leading to oro-nasal communication, providing data on the objective/subjective evaluation of such rehabilitation and mastication performance measured by a two-color chewing gum test. The type of defect was classified according to the classification system proposed by Aramany. Among the patients in our study, 72% rated a higher score for either stability and retention than for aesthetic appearance, as confirmed by the Kapur score rated by clinicians. The two-color chewing gum test shows similar results as only one patient had insufficient chewing function. Interestingly, we found no correlation between the masticatory function and residual denture, confirming that the maxillary obturator remains a predictable solution in such patients regardless of the anatomical alterations following surgery.

Masticatory function before and after masticatory muscle-related temporomandibular disorder treatment: An observational study

BACKGROUND

Muscle-related temporomandibular disorders (TMD) may affect the masticatory function. Chewing function can be assessed objectively using bolus-kneading tests, such as two-colour chewing-gum mixing ability test.

OBJECTIVE

The aim was to compare the masticatory function with a two-colour chewing-gum test before and after treatment of the masticatory muscle-related temporomandibular disorder.

METHODS

Twenty-one patients with masticatory muscle disorder according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were recruited as an experimental group, and further twenty-one participants without any TMD were included as controls. Pain intensity (scored on a visual-analogue scale) and maximum mouth opening (MMO) were recorded. Jaw Functional Limitation Scale-8 (JFLS-8) was conducted on all patients. Before and after treatment, masticatory function was evaluated with a validated bolus-kneading test, using two-colour chewing gum.

RESULTS

There was no statistically significant difference in chewing function before and after treatment in the experimental group (p = .715). When these values were compared with the control group, there were no statistically significant differences (p = .489, p = .890). There was no correlation between masticatory function and VAS, MMO, JFLS-8 before and after treatment in the experimental group.

CONCLUSION

The two-colour chewing-gum test is not sensitive when the masticatory performance is not severely impaired.

The Influence of Age and Oral Health on Taste Perception in Older Adults: A Case-Control Study

Declining gustatory function, nutrition, and oral health are important elements of health in older adults that can affect the aging process. The aim of the present work was to investigate the effect of age and oral status on taste discrimination in two different groups of elderly subjects living either in an Italian residential institution (TG) or in the community (CG). A total of 90 subjects were enrolled in the study (58 CG vs. 32 TG). Masticatory performance (MP) was assessed using the two-color mixing ability test. Taste function was evaluated using cotton pads soaked with six taste stimuli (salty, acid, sweet, bitter, fat and water). A positive correlation between age and missing teeth (r = 0.51, C.I. [0.33; 0.65], p < 0.0001), and a negative correlation between age and MP (r = −0.39, C.I. [−0.56; −0.20], p < 0.001) were found. Moreover, significant differences for salty taste, between TG and CG were detected (p < 0.05). Significant differences in bitter taste sensitivity between subjects wearing removable and non-removable prosthesis were also determined (p < 0.05). In addition, significant gender differences and between males in TG and CG were identified (p < 0.05). The best understanding of the relationship between MP, taste sensitivity, and nutritional factors is a necessary criterion for the development of new therapeutic strategies to address more effectively the problems associated with malnutrition in elderly subjects.

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.

CAD-CAM complete removable dental prostheses: A double-blind, randomized, crossover clinical trial evaluating milled and 3D-printed dentures

OBJECTIVE

This double-blind, randomized, crossover, clinical trial aimed to evaluate and compare the differences between milled and 3D-printed complete removable dental prostheses (CRDPs).

METHODS

Fifteen edentulous patients (men: n = 10, women: n = 5; age: 66.7 ± 8.0 years) rehabilitated with conventional CRDPs were recruited for this trial. Participants were randomized to first receiving either the milled or 3D-printed CAD-CAM manufactured CRDPs and then after 6-weeks cross over to the other set. Both, clinicians and participants were blinded to the group allocation. Outcomes included patient's denture satisfaction (PDS), oral-health related quality of life (OHIP-EDENT), willingness-to-pay analysis, final choice (FC) of CRDPs, clinician's denture quality evaluation (CDQE), chewing efficiency (CE), maximum-voluntary-bite-force (MBF), and prosthodontic maintenance needs. The outcomes were measured at baseline (with old CRDPs), at 1 and 6 weeks after new CRDP insertion; following crossover with the second set of CRDPs, an identical protocol was followed. Generalized linear regression for repeated measures was used for statistical analysis with α=0.05.

RESULTS

All participants completed the trial. 3D-printed CRDPs required more maintenance visits, adjustment time (p = 0.0003), and adjustment costs (p = 0.021). Patients were willing-to-pay an average of 606.67 Swiss Francs more than the actual cost for the milled CRDPs. There were no differences in the PDS, OHIP, FC, CDQE, CE, and MBF between the two CRDPs groups.

CONCLUSIONS

The findings of this double-blind randomized crossover clinical trial confirm that both milled and 3D-printed CRDPs are valid treatment modalities for edentulous patients, with the latter performing inferiorly with regard to the time and costs involved with the prosthodontic aftercare, as well as the patients' willingness-to-pay.

CLINICAL RELEVANCE

The findings of this trial provide evidence to help the clinician in choosing the appropriate CAD-CAM manufacturing process for fabricating the CRDPs.

Assessment of masticatory function in older individuals with bimaxillary implant-supported fixed prostheses or with a natural dentition: A case-control study

STATEMENT OF PROBLEM

A clinical assessment of the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses is lacking.

PURPOSE

The purpose of this case-control study was to compare the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses to that of those with a natural dentition by using a simplified comminution test with hard viscoelastic test food and a mixing ability test.

MATERIAL AND METHODS

Thirty-six participants were recruited and divided into 2 equal groups (n=18) based on their dental status. The experimental group (7 women, mean ±standard deviation age=69.8 ±7.5 years) had bimaxillary implant-supported fixed prostheses, and the control group (9 women, mean ±standard deviation age=68.3 ±5.6 years) had a natural dentition. A hard viscoelastic food comminution test and a mixing ability test with 2-colored chewing gum were performed in both groups. The number and total area of the particles during the comminution test and the variance of hue during the mixing ability test were measured. The data were analyzed with the parametric (paired t test) and nonparametric (Mann-Whitney U) tests to assess differences between the groups (α=.05).

RESULTS

The experimental group exhibited significantly fewer pieces in the food comminution test than the control group (P=.001). The experimental group also showed significantly higher variance of hue values than the control group (P<.001).

CONCLUSIONS

Patients treated with bimaxillary implant-supported prostheses had reduced masticatory performance in comparison to those with a natural dentition, despite having been provided with satisfactory and well-functioning prostheses.

Chewing function and related parameters as a function of the degree of dementia: Is there a link between the brain and the mouth?

Background

To date, no study has investigated the association between chewing function and related parameters as a function of the degree of dementia using a finer subdivision of the values of the Mini‐Mental State Examination (MMSE).

Objective

This study aimed to investigate the differences in chewing function and related parameters as a function of the degree of dementia.

Methods

An analysis of cross‐sectional data obtained from the OrBiD (Oral Health, Bite Force, and Dementia) pilot study was performed. The participants were stratified into five groups based on the outcomes of the MMSE (no dementia, MMSE 28–30; mild cognitive impairment, MMSE 25–27; mild dementia, MMSE 18–24; moderate dementia, MMSE 10–17; severe dementia, MMSE <10). The chewing efficiency, maximum occlusal force and related parameters (number of supporting zones, number of teeth, Eichner index, tooth/denture status, denture quality, and dental treatment needs) were recorded.

Results

The MMSE groups showed significantly different chewing efficiencies (p = .003, Jonckheere‐Terpstra test) and maximum occlusal forces (p = .003, Jonckheere‐Terpstra test), but the number of supporting zones (p = .055, chi‐square test) and the number of natural teeth (p = .126, chi‐square test) were not different. The Eichner index, tooth/denture status, denture quality and dental treatment need showed no significant associations with the degree of dementia.

Conclusion

An improvement in the usability of the measurement methods for assessing chewing function in people with dementia is needed. Research involving people with dementia is necessary because the nutritional situation often deteriorates rapidly within a multifactorial system, which includes chewing ability and oral health.

Oral function in amyotrophic lateral sclerosis patients: A matched case-control study

BACKGROUND & AIMS

Patients with amyotrophic lateral sclerosis (ALS) develop swallowing difficulties with the progression of the disease. The present study aimed at comparing oral function and body composition between ALS patients and healthy controls, and at evaluating which parameters are the most discriminant between both groups.

METHODS

We included ALS patients at the start of their multidisciplinary follow-up at the Geneva University Hospitals and healthy age-, gender-, and dental status-matched adults. We assessed the severity of the disease through the ALS Functional Rating Scale and the swallowing difficulties through the EAT-10 score. We performed an intraoral examination of the dental status, and measured chewing performance, bite, lip and tongue force, saliva weight, and body composition. Group comparisons were performed with t-tests or Mann-Whitney tests as appropriate. Linear discriminant analysis was used to determine the most discriminant parameters between groups.

RESULTS

Twenty-six ALS patients (bulbar onset: n = 7, median (IQR) ALS Functional Rating Scale: 37 (11)) were included. The ALS patients had a significantly lower chewing performance (p < 0.001), lip force (p < 0.001), tongue force (p = 0.002), saliva weight (p < 0.004) and fat-free mass index (p < 0.001) as compared to the healthy individuals, and a higher EAT-10 score (p < 0.001). In ALS patients, a low chewing performance was correlated with a low bite (r = -0.45, p < 0.05)) and tongue force (r = -0.59, p < 0.05). The most discriminant parameters between both groups, by order of importance, were chewing performance, fat-free mass index and saliva weight and allowed the calculation of a discriminant function.

CONCLUSION

Compared to healthy controls, ALS patients have significant alterations of oral function and body composition. The most discriminant parameters between both groups were chewing performance, fat-free mass index and saliva volume. It remains to be demonstrated whether oral parameters predict outcome. CLINICAL TRIAL REGISTRY: clinicaltrials.gov, identifier: NCT01772888.

Cognitive changes and neural correlates after oral rehabilitation procedures in older adults: a protocol for an interventional study

BACKGROUND

Epidemiological studies show an association between masticatory function and cognitive impairment. This has further strengthened the notion that tooth loss and impaired masticatory function may be risk factors for dementia and cognitive decline. Animal experiments have indicated a causal relationship and several possible mechanisms have been discussed. This evidence is, however, lacking in humans. Therefore, in the current interventional study, we aim to investigate the effect of rehabilitation of masticatory function on cognition in older adults.

METHODS

Eighty patients indicated for prosthodontic rehabilitation will be randomly assigned to an experimental or a control group. Participants will conduct neuropsychological assessments, masticatory performance tests, saliva tests, optional magnetic resonance imaging, and answer questionnaires on oral health impact profiles and hospital anxiety and depression scale before, 3 months, and 1 year after oral rehabilitation. The difference between the two groups is that the control group will be tested an additional time, (at an interval of about 3 months) before the onset of the oral rehabilitation procedure. The primary outcome is a change in measures of episodic memory performance.

DISCUSSION

Although tooth loss and masticatory function are widespread in older people, it is still an underexplored modifiable risk factor potentially contributing to the development of cognitive impairment. If rehabilitation of masticatory function shows positive effects on the neurocognitive function, this will have great implications on future health care for patients with impaired masticatory status. The present project may provide a new avenue for the prevention of cognitive decline in older individuals.

TRIAL REGISTRATION

The protocol for the study was retrospectively registered in ClinicalTrials.gov Identifier: NCT04458207, dated 02-07-2020.

How Do Changes in Oral Health and Chewing Efficiency Affect the Changes of Oral-Health-Related Quality of Life of Nursing-Home Residents in the Short Term?

Objective

To evaluate how changes in oral health and chewing efficiency affect the changes in oral-health-related quality of life (OHRQoL) of nursing-home residents over six months.

Methods

The study was conducted in nine nursing homes. Sociodemographic and general data were collected for all eligible individuals (n = 150). Of these, 114 participants (mean age 82.0 [± 9.5] years, 77.2% women) were available for the following tests at baseline and six months later: a comprehensive examination of dental and general health, a two-colour mixing-ability test (to assess chewing efficiency), the Geriatric Oral Health Assessment Index (GOHAI; to evaluate the OHRQoL), and the Mini Mental State Examination (MMSE; to diagnose the presence and severity of dementia). Univariate and multivariate linear regression models were compiled to analyse possible factors affecting OHRQoL.

Results

For the final analysis, 108 participants were available. For the study cohort as a whole, a decrease in the number of functional occluding pairs (C: 0.195; p = 0.034) and an increase in dental-treatment needs (C: −1.968; p = 0.056) had the greatest negative effects on OHRQoL as expressed by the GOHAI score. For denture wearers, a deterioration of denture condition (C: −2.946; p = 0.003) was the most important predictor for a decline in OHRQoL.

Conclusion

A short-term decline in oral health and function affects the OHRQoL of nursing-home residents. The most important dental variables in this regard are the number of functional occluding pairs and dental and denture-related treatment needs.

The use of digital texture image analysis in determining the masticatory efficiency outcome

The mixture level of gum samples consisting of two colours can be assessed visually, using the electronic colorimetric method, employing digital image processing techniques and specially designed software. The study investigates the possibility of an alternative method called "digital texture image analysis" (DTIA) to assess improvement of masticatory efficiency in denture wearers. The objectives were i) to evaluate whether DTIA discriminates changes in the colour mixing ability within a group over time; ii) to determine whether DTIA can be used to detect improvement in chewing ability; iii) to select the most appropriate DTIA feature that sufficiently describes masticatory efficiency in CDs wearers. The study was designed as an intra-individual evaluation of masticatory efficiency, which was assessed in participants with new dentures in three follow-up times. A set of four texture features was used in the current study. Uniformity, Contrast, Homogeneity and Entropy of the obtained chewing-gum samples were correlated to the degree of gum comminution. A statistically significant difference in masticatory efficiency was observed based on the values of the analysed DTIA variables of gum samples-Uniformity, Contrast, Homogeneity, and Entropy-have changed in the participants during the observation period. The improvement of the masticatory function in relation to the mixing ability of two-coloured chewing gum could be traced by monitoring changes in the values of DTIA variables. The most increasement of masticatory efficiency was observed by monitoring DTIA parameters such as contrast, and homogeneity.

Impact of rehabilitation with removable complete or partial dentures on masticatory efficiency and quality of life: A cross-sectional mapping study

STATEMENT OF PROBLEM

Tooth loss directly affects mastication, cognitive function, and oral health-related quality of life (OHRQoL). Complete dentures (CDs) and removable partial dentures (RPDs) represent a common oral rehabilitation approach. However, studies addressing the impact of removable dentures on replacing missing teeth are lacking.

PURPOSE

The purpose of this clinical study was to evaluate whether the OHRQoL, the jaw function limitation (JFL), and the masticatory efficiency of CD and RPD wearers are similar to those of patients with natural teeth and to evaluate whether wearing removable dentures can predict an effect on the OHRQoL, JFL, and masticatory efficiency of their wearers.

MATERIAL AND METHODS

The Oral Health Impact Profile (OHIP-14) questionnaire and the JFL scale were used to measure OHRQoL and JFL. Masticatory efficiency was analyzed by using a subjective color-mixing index for the chewing gum bolus and shape index and an objective colorimetric analysis by using a software program ViewGum. Data were analyzed with Kruskal-Wallis and post hoc Dunn tests, followed by multiple linear regression (α=.05).

RESULTS

The results from OHIP-14 evidenced that both denture groups presented a low impact on OHRQoL. JFL was higher for all denture wearers. For the subjective color-mixing analysis, the control and RPD groups presented better masticatory efficiency than CD wearers. Colorimetric analysis evidenced better masticatory efficiency for the control group, who differed from the CD and RPD groups. Wearing RPDs was a predictor of impaired JFL and OHRQoL, and the use of CDs was a predictor of impaired JFL and masticatory efficiency.

CONCLUSIONS

Despite being rehabilitated, CD and RPD wearers still had impaired OHRQoL, JFL, and masticatory efficiency. Also, the use of these prostheses can predict a negative effect on these 3 variables.

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.

Mandibular residual ridge morphology in relation to complete dentures and implant overdentures-Part II: Predictors for effectiveness of implant overdenture therapy

BACKGROUND

The significance of mandibular residual ridge height and satisfaction with conventional complete dentures (CCD) as predictors for the added value of implant-overdenture (IOD) therapy is unknown.

PURPOSE

To investigate the predictive value of thresholds for (1) residual ridge height at premolar location (PRH), and (2) satisfaction with CCD-stability for the added value of two intraforaminal implants supporting the mandibular CCD.

METHODS

Thirty CCD wearing patients (67.9 ± 7.0 years) for whom a new CCD was advised, received a new CCD. Mandibular gypsum models were digitally measured. After 3 months free of complaints (T1), perceived CCD-stability was evaluated, and participants received two intraforaminal implants. At T1 and T2 (3 months free of complaints after IOD therapy) participants completed OHIP14-CN, and denture satisfaction (VAS) questionnaires, and performed mixing ability tests. Participants were grouped according to PRH of ≥6.15 mm versus < 6.15 mm, and perceived CCD-stability satisfied vs. dissatisfied. Scores at T2 were compared to T1 (paired t-tests). Predictive values of PRH and CCD-stability were analyzed with logistic multivariate regression models.

RESULTS

At T2, only participants with PRH of <6.15 mm or dissatisfied with CCD-stability had significant lower OHIP-total and domain scores for 'physical pain' and 'physical disability' and significantly higher VAS scores for perceived chewing function, denture retention and oral comfort. Regression analyses showed that participants with PRH of <6.15 mm, or dissatisfied with CCD-stability had significantly higher chance for lower OHIP-total and domain scores 'physical pain' and 'physical disability', and for higher VAS scores for perceived chewing function, denture retention and oral comfort at T2. Masticatory performance improved significantly after IOD therapy, but independent of PRH and CCD-stability.

CONCLUSION

PRH and satisfaction with CCD-stability were adequate prognostic indicators for improvement of oral health-related quality of life and denture satisfaction by mandibular IOD therapy.

Rationale and Methodology of The PopulatION HEalth and Eye Disease PRofile in Elderly Singaporeans Study [PIONEER]

To describe the rationale, design and methodology of a geographically-representative and population-based study investigating the epidemiology, impact, personal and economic burden of age-related eye diseases, declining visual and other sensory systems in Asians aged >60 years in Singapore.PIONEER (The PopulatION HEalth and Eye Disease PRofilE in Elderly Singaporeans Study) is currently a cross-sectional study targeting 3152 Chinese, Malay and Indian adults who are Singapore citizens or permanent residents aged 60 years and older living across Singapore. The study is intended to be longitudinal, with several waves of data planned to be collected in the future. The sampling frame consisted of 7000 names derived from age, gender and ethnicity-stratified random sampling of individuals >60 years. Selected individuals were invited via letters, home visits, and telephone calls for a clinical assessment at the Singapore Eye Research Institute. Individuals with limited mobility were examined in a custom-designed mobile eye clinic. Questionnaires were subsequently administered at participants' homes by trained interviewers in their preferred language. A total of 3,299 participants (from East, West, North and South Singapore) were approached from December 2017 to November 2019. Of these, 953 (28.5%) were deemed ineligible. Out of 2,346 eligible participants, 904 (38.5%) refused, and 1,442 (61.5%) attended our clinical testing protocol, giving an initial response rate of 61.5%. Of these, 1,170 (81%) were cognitively able to complete the questionnaire assessment. The mean age±SD of our participants was 73.8±8.6 years; n=798 (55.3%) were female; and 828 (57.4%) were of Chinese ethnicity. The findings from this study will allow a deeper understanding of the risk factors and impact of aging in Asian populations, particularly in relation to the visual function and other functional system.

The Effects of Dental Status and Chewing Efficiency on the Oral-Health-Related Quality of Life of Nursing-Home Residents

Objective

The aim of this study was to evaluate the effects of dental status and chewing efficiency on the oral-health-related quality of life (OHRQoL) of nursing-home residents.

Materials and Methods

The study was conducted in nine nursing homes. All eligible participants were included, and general and medical data, information about nutritional status and their dental and prosthetic status were collected. Chewing efficiency was assessed by means of a two-colour mixing-ability test. The simple count version of the Geriatric Oral Health Assessment Index (SC-GOHAI) was used to evaluate participants’ OHRQoL, and the Mini-Mental State Examination to classify the presence of cognitive impairment. Univariate and multivariate regression models were used to analyse data.

Results

The mean age of the participants was 82.1 (± 9.8) years and most participants suffered from at least very mild cognitive impairment. OHRQoL for all participants (n = 143) and denture wearers only (n = 105) was substantially associated with the type of prosthesis, the presence of natural teeth, the number of functional occluding pairs and dental and denture-related (if applicable) treatment needs. Furthermore, in both model’s univariate analysis showed that chewing efficiency also affected OHRQoL. In contrast, multivariate analysis of all participants revealed that only a higher number of functional occluding pairs (C: 0.250; p < 0.001), fewer dental treatment needs (C: −1.733; p = 0.019) and a better nutritional status (C: −1.298; p = 0.048) were relevant for better OHRQoL. For denture wearers, a higher number of functional occluding pairs (C: 0.192; p = 0.011), a better denture condition (C: −2.194; p= 0.003) and a higher body mass index (BMI) (C: 0.145; p = 0.006) were the main variables associated with better OHRQoL among participants.

Conclusion

Good oral health and oral function, including chewing efficiency, are associated with a high OHRQoL of nursing-home residents. However, few dental treatment needs, well-fitting dentures without treatment needs and a high number of functional occluding pairs seem to be the principal variables for an acceptable OHRQoL of nursing-home residents.

Development and validation of a chewing function questionnaire for Chinese older adults

OBJECTIVES

To develop and validate a questionnaire for assessing chewing function of Chinese older adults.

METHODS

The chewing function questionnaire was validated on older adults recruited from a dental hospital, an elderly home and three community centers in Hong Kong. The participants were asked to indicate their ability to chew on each of the 20 selected food items and to self-rate their overall chewing ability. Chewing function was objectively assessed by asking the participant to chew a color-changeable gum for 90 s. The color of the chewed gum was assessed using a colorimeter. Participant's maximum bite force was also measured by an electronic detector.

RESULTS

A total of 211 elders participated in this study. Ten out of the 20 food items were selected to create the final unidimensional chewing function questionnaire (CFQ). The overall Cronbach's alpha value for the CFQ was 0.912. The weighted kappa value of each food item ranged from 0.6 to 1. In general, participants with larger color change of the chewed gum had significantly higher median rank of the CFQ total score and of the score of each food item (p < 0.01). The CFQ total score was correlated with the color change of the chewed gum as measured by colorimeter (p < 0.001), the maximum bite force (p < 0.001) and self-rated chewing ability (p < 0.001).

CONCLUSION

The new unidimensional chewing function questionnaire is a valid and reliable questionnaire for assessing self-rated chewing ability of Chinese older adults.

CLINICAL SIGNIFICANCE

The newly developed self-reported questionnaire can be used to assess the chewing function of Chinese older adults and dentists can use the information obtained to discuss with their patients regarding the need for oral function rehabilitation, such as the treatment need for fixed or removable dental prosthesis.

Comparison of smartphone-camera and conventional flatbed scanner images for analytical evaluation of chewing function

BACKGROUND

The two-colour mixing test is a quick method to assess chewing function (CF). The use of smartphone cameras for acquiring images may help in further simplifying the process.

OBJECTIVE

This study evaluated the reliability of smartphone-camera images of chewing gums to assess CF.

METHODS

Five test samples of a bicoloured chewing gum were produced by a single fully dentate adult volunteer. The specimens were flattened to 1-mm thick wafers. The two sides of the wafers were digitised with a conventional flatbed scanner (control) and were photographed 20 times using 8 different smartphones. The images were assessed optoelectronically to obtain the variance of hue (VoH) and subjectively by visual assessment (SA) using a categorical scale (SA1-SA5). Spearman's correlation and regression models were used for statistical analyses.

RESULTS

The intra-group variability for SA1-SA3 was <1% for all smartphones, but significantly higher than controls for SA4 and SA5 (smartphone: SA4 = 5.57%; SA5 = 8.76%; control: SA4 = 2.5%; SA5 = 0.79%). VoH was progressively lower from SA1 to SA5 for all imaging devices (r > -.97; P < .001). VoH comparisons between control and smartphone images revealed significant differences for the individual SA categories, and however, the magnitude of differences was small and non-significant when the full range of SA levels were considered. The linear mixed model regression showed significant effects for all the smartphones (P < .001) and SA levels (P < .001) in relation to the flatbed scanner values.

CONCLUSIONS

Smartphone cameras may be used to evaluate colour mixture for a bolus-kneading test, however, the precision is lower with higher degrees of colour mixing.

Clinical Oral Disorders in Adults Screening Protocol (CODA-SP) from the 2019 Vancouver IADR Consensus Symposium

BACKGROUND

The Clinical Oral Disorder in Elders (CODE) index was proposed in 1999 to assess the oral health status and treatment needs of older people who typically were edentate or had few natural teeth. Since then, more people are retaining natural teeth into old age and have oral disorders similar to younger adults. In addition, there has been further guidance on screening for disease that includes changes to the clinical indicators of several oral disorders and greater sensitivity to people's concerns about their oral health and care needs.

METHODS

Experts in dental geriatrics assembled at a satellite symposium of the International Association of Dental Research in June 2019 to revise the objectives and content of the CODE index. Before the symposium, 139 registrants were asked for comments on the CODE index, and 11 content experts summarised current evidence and assembled reference lists of relevant information on each indicator. The reference lists provided the base for a narrative review of relevant evidence supplemented by reference tracking and direct searches of selected literature for additional evidence.

RESULTS

Analysis of the evidence by consensus of the experts produced the Clinical Oral Disorders in Adults Screening Protocol (CODA-SP).

CONCLUSIONS

The CODA-SP encompasses multiple domains of physical and subjective indicators with weighted severity scores. Field tests are required now to validate its effectiveness and utility in oral healthcare services, outcomes and infrastructure.

Mandibular two-implant overdentures with CAD-CAM milled bars with distal extensions or retentive anchors: A randomized controlled trial

OBJECTIVE

This randomized controlled trial (RCT) aimed to demonstrate the non-inferiority of mandibular 2-implant overdentures (IODs) on a CAD-CAM milled bar with long distal extensions (MBDE) against IODs on retentive anchors (RA).

METHODS

Forty edentulous participants rehabilitated with a maxillary conventional denture and a mandibular 2-IOD participated in this trial. They were randomized into two groups [Control group (CG): RA + gold matrices; Experimental group (EG): MBDE + gold clip]. The outcomes included implant survival rate (ISR), chewing efficiency [quantitative (VoH) and subjective (SA) assessments], peri-implant marginal bone levels (PI-MBL), maximum bite force (MBF), and patient-reported outcomes [oral health impact profile (OHIP-EDENT), and denture satisfaction index (DSI)]. Outcomes were recorded at baseline (BL), two weeks (T₀ ), 6 months (T₁ ), and at 1 year (T₂ ) after the intervention. Intra- and inter-group analyses were performed using regression models with ⍺=0.05.

RESULTS

38 participants completed the T₂ visit (CG: n = 19, age = 74.7 ± 7.8 years; EG: n = 19, age = 70.3 ± 10.7 years). At T₂ , there was no implant loss in either of the groups (ISR = 100%). There were no significant differences between the groups for the PI-MBL changes (p = .754). Improvements occurred faster in the EG than in the CG, but over the observation time, there were no differences between the trial groups for VoH, MBF, OHIP-EDENT, and the DSI, except for SA being significantly better in the EG group (p = .022).

CONCLUSIONS

The results of this RCT confirm that mandibular 2-IODs with a CAD-CAM milled bar with long distal extensions are not an inferior treatment to the conventional IODs on retentive anchors in the short term (1 year).

A novel method for assessing oral mixing ability based on the spatial clusters quantified by variogram

BACKGROUND

The two-colour chewing test (TCCT) has been widely used for assessing oral mixing ability, a critical component of masticatory performance. Most studies focused on quantifying the evenness of colour distribution. It remained unknown if the variation of colour clustering was a valid index of oral mixing ability.

OBJECTIVE

The study aims to investigate the oral mixing ability based on the spatial clusters quantified by variogram.

METHODS

Fifty older people (15 male/35 female, age: 66.0 ± 7.8 years) were assessed for the TCCT and the colour-changeable chewing gum test (CCGT). For the CCGT, we quantified the degree of colour change (ΔE). For the TCCT, the highest peak in colour histogram (HP), the standard deviation of colour values (SDC) and the range of variogram from colour spatial distribution (VARG) were quantified. The participants were grouped according to the contacts of posterior teeth, as assessed by Eichner Index (EI).

RESULTS

Highest peak, SDC and VARG showed statistically significant differences between the EI groups (two-tailed independent t test P < .05). Higher VARG (ie a lower degree of clustering) was significantly negatively correlated with ΔE (r = -.36, one-tailed P < .01). The binary logistic regression revealed that among the spatial indices (HP, SDC and VARG), only VARG achieved statistical significance in prediction to the EI group. Eliminating other indices was insignificant to the model performance.

CONCLUSIONS

Our results show that the averaged cluster sizes, quantified by variogram, are a valid index for quantifying the TCCT. Compared with other spatial indices, it had the best predictability to the condition of posterior contact.

Reliability and comparability of methods for assessing oral function: Chewing, tongue pressure and lip force

BACKGROUND

Quantitative clinical assessment tests for oral function have become popular in patient assessment; however, their comparability remains unclear.

OBJECTIVE

To assess the reliability and comparability of pairs of different instruments for measuring maximum tongue pressure (MTP), chewing function (CF) and maximum lip force (MLF), and to analyse the influence of subjects' characteristics on the applied instruments.

METHODS

Each pair of instruments, as well as a single device measuring the maximum voluntary bite force (MBF), was assessed across 26 healthy volunteers. The respective pairs of devices were compared using Bland-Altman plots and linear regression analysis. Furthermore, the influence of age, occlusal support zones, number of functional occlusal units, MBF, MTP and MLF were investigated as predictors on CF using a generalised estimating equation model.

RESULTS

Neither the two assessments of CF, nor of MLF were correlated to each other, but there was a significant correlation between the assessments of MTP. Hue-Check Gum was able to demonstrate a significantly higher CF in younger compared to older individuals (P = .004) and individuals with high numbers compared to low numbers of occlusal units (P < .001). Those differences could not be demonstrated with the Vivident chewing gum.

CONCLUSION

The absolute values of MTP assessed by the two applied devices cannot directly be compared, although normalised values may be directly comparable. Moreover, our observations suggest that the Hue-Check Gum was able to discriminate the effects of age and the number of occlusal units on CF. Our observations suggest that the two gums cannot be used interchangeably.

Masticatory Adaptation to Occlusal Changes

This review deals with the frequent wide variability of masticatory capacity/incapacity. Neither researchers nor clinicians have taken sufficient account of this variability despite its implications for nutrition. Mastication in normal healthy oral conditions is first described, followed by a short presentation of the mechanisms of masticatory adaptation in the nervous system. Capacity, incapacity, and successful compensatory adaptation of mastication are then defined, along with the different methods used for their evaluation. Examples of adaptation needs are given, such as those concomitant with dental wear or occlusal changes. Finally, given its vital importance for deeply impaired mastication/deglutition function, the impact of masticatory adaptation processes on nutrition is examined.

Impact of Elderly Masticatory Performance on Nutritional Status: An Observational Study

Background and Objectives: Masticatory limitations on the dietary habits of edentulous subjects restrict their access to adequate nutrition, exposing them to a greater risk of protein energy malnutrition. The aim of this study is to verify the existence of an association between Masticatory Performance (MP) and nutritional changes in the elderly. Materials and Methods: 76 participants were enrolled. MP testing was performed using the two-color chewing gum mixing test. The system used reveals the extent to which the two differently colored chewing gums mix, and allows discrimination between different MPs. The assessment of the participants' nutritional statuses was carried out through a food interview. Anthropometric parameters were collected, and bioimpedance analysis was performed. Results: Mean MP was 0.448 ± 0.188. No statistically significant differences were detected between male and female subjects (p > 0.05). According to the Body Mass Index (BMI), obese patients had a lower MP than overweight and normal weight subjects (0.408 ± 0.225, 0.453 ± 0.169 and 0.486 ± 0.181, respectively). MP values were lower both in male and female subjects with a waist circumference above the threshold than those below it (0.455 ± 0.205 vs. 0.476 ± 0.110, respectively, in males and 0.447 ± 0.171 vs. 0.501 ± 0.138, respectively, in females). No relationship was noticed between MP and bioimpedance parameters (p > 0.05). Conclusions: A statistically significant relation was observed between MP and the number of missing teeth. A reduced MP could worsen nutritional parameters. A reduced MP did not seem to negatively affect bioimpedance parameters.

Orofacial Functions and Chewing Effiency in Elderly Patients with Parkinson’s Disease Rehabilitated with Removable Prostheses

Background:

Parkinson’s Disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. It is one of the movement disorders that can affect oro-facial conditions. It is more common in the elderly, having an average age of onset of around 60 years.

Objective:

The aim was to study orofacial functions in patients suffering from PD with partial or total edentulism, wearing removable prostheses.

Methods:

Forty-eight (48) elders, rehabilitated with removable dentures, were included: 24 patients suffering from Parkinson's disease constitute the Study Group (SG), and 24 subjects not suffering from Parkinson's disease or neurological degenerative diseases represent the Control Group (CG).

In SG, the severity of Parkinson's disease was assessed according to the Unified Parkinson's Disease Rating objective motor scale III, and oro-facial dysfunctions were evaluated using Nordic Orofacial Test-Screening (NOT-S). The duration of the use of dental prostheses expressed in years has been reported. In both the groups, the subjective chewing index for the analysis of masticatory ability and the two-color chewing gum test for the analysis of masticatory efficiency were conducted .

Results:

There was a statistically significant difference between the SG and CG compared to the NOT-S (P = 0.001).

Analyzing the study group, a statistically significant correlation was found between the masticatory efficiency and prosthetic years of use (rs = 0.436; P <0.05); instead, no statistically significant correlation was found between the masticatory efficiency and the severity of Parkinson's disease.

Conclusion:

In our study, we did not find differences between SG and CG in terms of the degree of masticatory efficiency; therefore, only a correlation between the duration of use of dental prostheses and the degree of masticatory efficiency was found.