Novel software for quantitative evaluation and graphical representation of masticatory efficiency

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.

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.

Mandibular overdenture with a single implant in the canine region (c-SIMO): a feasibility study

OBJECTIVES

The aim of this multi-center pilot study was to assess the viability and feasibility of a novel treatment concept - the canine-positioned single implant mandibular overdenture (c-SIMO), with the single implant placed on the patient's preferred chewing side instead of the midline.

MATERIALS AND METHODS

Participants received a single implant in the canine region of their preferred chewing side, based on an Asymmetry Index observed during mastication. The pre-existing mandibular denture was transformed into a c-SIMO on a spherical attachment. The primary outcome was oral health-related quality of life (OHRQoL), measured with GOHAI and OHIP-EDENT. Secondary outcomes included denture satisfaction index (DSI), chewing efficiency (CE), maximum bite force (MBF), implant survival and success, and prosthetic maintenance. Data analysis included descriptive statistics and bivariate comparison tests.

RESULTS

Fifteen participants received the c-SIMO treatment (mean age: 69.9 ± 7.0). Implant success and survival rates were 100% at 1 year. Patient-reported outcome measures improved significantly compared to pre-treatment values (OHIP-EDENT: p = 0.001; DSI: p = 0.001; GOHAI: p = 0.002). Masticatory outcomes also improved significantly (CE: p = 0.001; overall MBF: p = 0.005). Post-implant, MBF was significantly higher in the ipsilateral side compared to the contralateral side at 2 weeks (p = 0.019) and 3 months (p = 0.015), but no longer at T3 (p = 0.730). Common prosthodontic events included denture base adjustments (n = 17) and matrix activation (n = 9).

CONCLUSIONS

This pilot study concludes that c-SIMO is a promising treatment option, and a potential alternative to the single midline implant overdenture.

CLINICAL RELEVANCE

The novel treatment concept of a canine-positioned single implant mandibular overdenture could be a viable treatment alternative to the midline positioning.

Accuracy of newly developed color determination application for masticatory performance: Evaluating color-changeable chewing gum

PURPOSE

Color-changeable chewing gums are used to evaluate masticatory performance, as measured by a colorimeter or visually based on a color scale. Although anyone can use a color scale, the evaluation accuracy depends on the evaluator. We develop an application that can determine the degree of color change in chewing gum using smartphone images, making color evaluation accurate and easy to measure.

METHODS

For the application, 60 chewed gum samples were prepared. Two shots were captured using two smartphone models. To create the application algorithm, a formula was developed to approximately map the color value from the smartphone images to the true value using a colorimeter. A basic validation was performed on 60 new samples covering a range of colors, followed by a field validation on 100 healthy dentate participants aged 20-39 years.

RESULTS

The intraclass correlation coefficient for two repeated shots had a high value ≥ 0.97 in the basic and field validations, confirming reliability. No significant differences were observed in the paired t-test and Wilcoxon signed-rank test, and a significant and strong correlation (correlation coefficient ≥ 0.92) was observed between the evaluation values using the colorimeter and the basic and field validations. Bland-Altman plots further confirmed the validity of the application.

CONCLUSIONS

A software application was developed to enable easy, quick, and accurate determination of the masticatory performance of a chewing gum from images taken using a smartphone with highly reliable and validated results.

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.

DIGITAL DENTISTRY AND ITS IMPACT ON ORAL HEALTH-RELATED QUALITY OF LIFE

Over the past 50 years, digitization has gradually taken root in dentistry, starting with computer tomography in the 1970s. The most disruptive events in digital dentistry were the introduction of digital workflow and computer-aided manufacturing, which made new procedures and materials available for dental use. While the conventional lab-based workflow requires light or chemical curing under inconsistent and suboptimal conditions, computer-aided manufacturing allows for industrial-grade material, ensuring consistently high material quality. In addition, many other innovative, less disruptive, but relevant approaches have been developed in digital dentistry. These will have or already impact prevention, diagnosis, and therapy, thus impacting patients' oral health and, consequently, their oral health-related quality of life. Both software and hardware approaches attempt to maintain, restore, or optimize a patient's perceived oral health. This article outlines innovations in dentistry and their potential impact on patients' oral health-related quality of life in prevention and therapy. Furthermore, possible future developments and their potential implications are characterized.

Digital oral health biomarkers for early detection of cognitive decline

BACKGROUND

Oral health could influence cognitive function by stimulating brain activity and blood flow. The quantified oral status from oral inflammation, frailty and masticatory performance were rarely applied to the cognitive function screening. We aimed to adopt non-invasive digital biomarkers to quantify oral health and employ machine learning algorithms to detect cognitive decline in the community.

METHODS

We conducted a prospective case-control study to recruit 196 participants between 50 and 80 years old from Puzi Hospital (Chiayi County, Taiwan) between December 01, 2021, and December 31, 2022, including 163 with normal cognitive function and 33 with cognitive decline. Demographics, daily interactions, electronically stored medical records, masticatory ability, plaque index, oral diadochokinesis (ODK), periodontal status, and digital oral health indicators were collected. Cognitive function was classified, and confirmed mild cognitive impairment diagnoses were used for sensitivity analysis.

RESULTS

The cognitive decline group significantly differed in ODK rate (P = 0.003) and acidity from SILL-Ha (P = 0.04). Younger age, increased social interactions, fewer cariogenic bacteria, high leukocytes, and high buffering capacity led to lower risk of cognitive decline. Patients with slow ODK, high plaque index, variance of hue (VOH) from bicolor chewing gum, and acidity had increased risk of cognitive decline. The prediction model area under the curve was 0.86 and was 0.99 for the sensitivity analysis.

CONCLUSIONS

A digital oral health biomarker approach is feasible for tracing cognitive function. When maintaining oral hygiene and oral health, cognitive status can be assessed simultaneously and early monitoring of cognitive status can prevent disease burden in the future.

The combined orthodontic and restorative treatment for patients with malocclusion and dentition defects: A randomized controlled trial

BACKGROUND

To explore the effects of a combined orthodontic and restorative approach on chewing, swallowing, and language function in patients with malocclusion and dental defects.

METHODS

A total of 112 patients with malocclusion and dentition defects admitted to the Lianyungang Hospital of Traditional Chinese Medicine from June 2019 to June 2022 were prospectively selected. The patients were divided into study and control groups using a simple random number table method, with 56 patients in each group. The control group received routine restoration, whereas the study group received a combination of orthodontic and restorative treatments. The chewing function, swallowing and language function, and gingival periodontal condition before and after treatment in both groups were compared using t-test or Wilcoxon test, while treatment satisfaction were compared using chi-square test or Fisher exact test.

RESULTS

After treatment, maximum area frame bite force/max movie force in both groups increased compared to before treatment, while occlusion time, bite force distrbution balance, and standard deviation hue decreased compared to before treatment. Moreover, maximum area frame bite force/max movie force in the study group was higher than that in the control group, whereas occlusion time, bite force distrbution balance, and standard deviation hue were lower than those in the control group (P < .05). The swallowing and language function scores of the study group were higher than those of the control group (P < .05). After treatment, the bleeding index, plaque index, and probing depth of both groups decreased compared to before treatment, and the study group was lower than the control group (P < .05). The treatment satisfaction of the study group (94.64%) was higher than that of the control group (82.14%) (P < .05).

CONCLUSION

Adopting a combined orthodontic and restorative approach to intervene in patients with malocclusion and dentition defects is beneficial for improving their periodontal condition, effectively restoring chewing, swallowing, and language functions, and achieving high patient satisfaction.

Assessment and Improvement of Masticatory Performance in Frail Older People: A Narrative Review

According to the World Health Organization (WHO), the estimated number of older adults is around 962 million and is projected to increase to 2.1 billion by 2050. The oral frailty concept is associated with gradual oral function loss in relation to aging. There is a need to emphasize the improvement of oral function based on an evaluation of masticatory performance in patients with various oral conditions or systemic diseases and especially in the frail elderly. The present narrative review presents an overview of the current state of the assessment and improvement of masticatory performance in frail older people. To fully encompass oral frailty, oro-facial hypofunction, or oro-facial fitness, dental Patient Reported Outcomes (dPROs) should be included; nevertheless, there are limited evidence-based rehabilitation approaches. The concept of oral frailty, oro-facial hypofunction, or oro-facial fitness should involve dental Patient Reported Outcomes (dPROs), and in this sense, there are only a few evidence-based rehabilitation procedures to improve oro-facial hypofunction besides prosthodontics. It must be considered that reduced neuroplastic capacity in old individuals might preclude a positive outcome of these strategies that might need to be accompanied by functional training and nutritional counseling.

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.

Clinical evaluation of complete denture fabricated using two different final impression techniques on masticatory efficiency and oral health-related quality of life

Aim

To compare the effect of complete denture fabricated using selective pressure impression and functional impression technique on masticatory efficiency and oral health-related quality of life (OHRQoL) in patients with resorbed ridges.

Settings and Design

A randomized two arm, parallel group study.

Materials and Methods

Forty-eight participants with set inclusion and exclusion criteria were randomly allocated into two groups. Complete denture was fabricated in Group A and Group B using selective pressure and functional impression technique, respectively. The follow-up was done at 3 months. Masticatory efficiency was measured by color-changing chewing gum, and OHRQoL was assessed using the Geriatric Oral Health Assessment Index (GOHAI) Hindi Version.

Statistical Analysis Used

The Wilcoxon signed-rank test was applied to check the intergroup analysis for the GOHAI scores of both impression techniques. The Mann-Whitney U test was applied to compare intragroup analysis for masticatory efficiency and the GOHAI scores of both the techniques.

Results

A total of 45 participants completed the follow-up. The mean age of the total participants was 62.7 ± 3.8. No statistically significant difference (P > 0.05) was observed between the masticatory efficiency and post-GOHAI scores of both the impression techniques.

Conclusion

Selective pressure and functional impression techniques may be successfully used to fabricate complete dentures for patients with resorbed ridges.

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.

Assessing masticatory performance with a colour-mixing ability test using smartphone camera images

Background

Colour‐mixing ability tests are frequently used to assess masticatory performance, but the image acquisition process may be cumbersome and technique sensitive.

Objectives

To evaluate the reliability of smartphone camera images in assessing masticatory performance using a colour‐mixing ability test.

Methods

Participants were recruited into three groups of dental state (n = 20 each): fully dentate, removable partial denture wearers and complete denture wearers. After performing a colour‐mixing ability test, images of the gum specimens (Hue‐Check Gum©) were captured with two smartphones and compared with the images obtained from a flatbed scanner by two examiners. The images were analysed with a subjective‐ (SA) and an opto‐electronical assessment (VoH). Inter‐ and intra‐rater reliability were tested. ANOVA models with repeated measures were used for statistical analysis (⍺ = .05).

Results

All three image acquisition techniques were able to distinguish masticatory performance between different dental states. For SA, inter‐rater reliability was fair to substantial and intra‐rater reliability was substantial to almost perfect. For VoH, inter‐rater reliability with the smartphones was at times different between two examiners, but the intra‐rater assessment was reliable. The opto‐electronic analysis with smartphone images underestimated the masticatory performance significantly when compared to the flatbed scanner analysis. Seven‐day ageing of the specimens did not significantly affect the results.

Conclusions

The assessment of masticatory performance with the Hue‐Check Gum© is a reliable method. The use of smartphones may occasionally underestimate masticatory performance; image acquisition with a flatbed scanner remains the gold standard. A centralised analysis of the photographed wafer may foster the reliability of the diagnosis.

Children and adolescents with speech sound disorders are more likely to have orofacial dysfunction and malocclusion

Background

Children with speech sound disorders (SSD) form a heterogeneous group that differs in terms of underlying cause and severity of speech difficulties. Orofacial dysfunction and malocclusions have been reported in children with SSD. However, the association is not fully explored.

Objectives

Our aims were to describe differences in orofacial function and malocclusion between a group of children and adolescents with compared to without SSD and to explore associations between those parameters among the group with SSD.

Methods

A total of 105 participants were included, 61 children with SSD (6.0–16.7 years, mean age 8.5 ± 2.8, 14 girls and 47 boys) and 44 children with typical speech development (TSD) (6.0–12.2 years, mean age 8.8 ± 1.6, 19 girls and 25 boys). Assessments of orofacial function included an orofacial screening test and assessment of bite force, jaw stability, chewing efficiency, and intraoral sensory‐motor function. Possible malocclusions were also assessed.

Result

Children with SSD had both poorer orofacial function and a greater prevalence of malocclusion than children with TSD. Furthermore, children with SSD and poorer orofacial function had a greater risk of malocclusion.

Conclusion

Our result suggests that children with SSD are more prone to having poorer orofacial function and malocclusion than children with TSD. This illustrates the importance of assessing coexisting orofacial characteristics in children with SSD, especially since orofacial dysfunction may be linked to an increased risk of malocclusion. This result highlights the need for a multiprofessional approach.

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.

Oral factors and adherence to Mediterranean diet in an older Greek population

PURPOSE

The aim of this study was to investigate the effect of oral factors on adherence to the Mediterranean diet in an older population METHODS: 130 persons over 60 years visiting Open Care Community Centers for Older People participated in this study. Oral interviews recorded demographic and sociomedical information, subjective oral complaints, and dental habits. Adherence to Mediterranean diet was assessed using the MDI_BNC4H index (range: 0-14). An oral examination was performed, and evaluation of the masticatory performance was carried out using a two-color chewing gum that was digitally analysed.

RESULTS

The mean age of the study participants was 73.9 ± 8.5 years. The score of adherence to the Mediterranean diet ranged from 3 to 9 (5.6 ± 1.4). 58 participants used removable prostheses, while 20 used a pair of complete dentures. Univariate analyses revealed that the parameters that negatively significantly, or marginally significantly, affected the level of adherence to the Mediterranean diet were lower masticatory performance (p = 0.050), larger number of drugs per day (p = 0.056), higher BMI (p = 0.043) and smoking (p = 0.053). The multivariable analysis revealed that lower adherence to the Mediterranean diet was significantly associated with higher BMI (p = 0.047) and lower masticatory performance (p = 0.050).

CONCLUSIONS

Increased masticatory performance was an independent predictor of better adherence to the Mediterranean diet in an older population.

Sociomedical and oral factors affecting masticatory performance in an older population

OBJECTIVES

To assess the sociomedical and oral factors affecting masticatory performance in a community-dwelling older population.

MATERIALS AND METHODS

Community-dwelling persons over 60 years were investigated using medical and dental oral interviews, oral and denture examination (natural teeth, tooth mobility, number of occluding tooth pairs, and removable dentures' prevalence and quality), and evaluation of masticatory performance using a mixing ability test.

RESULTS

A total of 130 participants with a mean age of 73.9±8.5 years were recorded. Fifty-eight (44.6%) used various types of removable prostheses. Twenty were edentulous and used a pair of complete dentures. Univariate analyses revealed statistically significant associations (p≤0.05) between masticatory performance and aging, marital status, subjective chewing ability, use of removable dentures, use of various combinations of complete dentures, pain caused by maxillary denture, number of teeth, tooth mobility, posterior chewing pairs, all chewing contacts natural or prosthetic, retention of mandibular partial dentures, and dentures' occlusion. The multivariable quantile regression analysis revealed that fewer natural teeth (95% CI: -0.02-0.01, p<0.001), being edentulous and using a pair of complete dentures (95% CI: 0.09-0.35, p=0.001), and larger percentage of severely mobile teeth (95% CI: 0.07-0.82, p=0.020) were associated with lower masticatory performance.

CONCLUSIONS

Poor masticatory performance in older adults was associated with fewer teeth, being edentulous and using a pair of complete dentures, and increased prevalence of severe tooth mobility.

CLINICAL RELEVANCE

Retaining the natural dentition and preventing and treating periodontal disease are important measures to maintain masticatory performance in older adults.

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.

Oral diadochokinesis and associated oro-facial function in young and old German mother-tongue speakers: A cross-sectional study

Objectives

The aims of this study were to compare oral diadochokinesis and to test associations with oro‐facial functional parameters in healthy young and old German speakers.

Background

Oral diadochokinesis is a key component in the concept of oro‐facial hypofunction and relates to tongue and lip motor function but may depend on the linguistic background.

Materials and methods

Healthy German speakers with a minimum of 20 teeth were recruited to form a young (<60 years) and an older group (≥60 years). Oral diadochokinesis was assessed as the number of repetitions/s for the monosyllables /pa/, /ta/ and /ka/ to evaluate movement capacity of the lip, the anterior region of the tongue and the posterior region of the tongue, respectively. Maximum voluntary lip force, maximum voluntary bite force, masticatory performance, maximum voluntary tongue pressure, xerostomia and swallowing function were assessed with validated instruments. Results are presented as median (IQR).

Results

Sixty participants formed the younger group (n = 35, 30.0 years [24.0‐49.0]) and the older group (n = 25, 64.0 years [62.0‐72.0]). Counts/s of /ta/ were different between age groups (younger group: 6.0 vs older group: 5.4) but not for syllables /pa/ (younger group: 6.0 vs older group: 5.8) and /ka/ (younger group: 5.6 vs older group: 5.0). The oral diadochokinesis with /pa/ was overall associated with maximum voluntary lip force; oral diadochokinesis performed with /ta/ was associated with tongue pressure, and oral diadochokinesis with /ka/ with swallowing function. Masticatory performance was not associated with oral diadochokinesis but with maximum voluntary bite force, xerostomia and with maximum voluntary tongue pressure.

Conclusions

The published thresholds for oral diadochokinesis should be reconsidered in non‐Japanese mother‐tongue speakers. However, they still play an important role in the overall concept of oro‐facial functional assessment.

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.

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.

Patient satisfaction and masticatory performance of zirconia bar compared to cobalt chromium bar retaining mandibular implant overdenture: A crossover study

OBJECTIVES

The aim of this crossover clinical study was the evaluation and comparison of patient satisfaction and masticatory performance for patients rehabilitated with mandibular two implant overdentures retained with two different bar attachments: zirconia bar and cobalt chromium bar.

MATERIAL AND METHODS

Twenty completely edentulous patients were divided into two equal groups: Group I (ZrO2), each patient received mandibular implant overdenture retained with CAD/CAM zirconia bar on two implants in the canine region, and Group II (Co-Cr), each patient received mandibular overdenture retained with conventional casted cobalt chromium metal bar. Patient satisfaction was measured with a survey questionnaire (PSQ-18), and masticatory performance was also evaluated with the two-colour mixing ability test after 3 months of overdenture insertion; then, each patient received a bar attachment from the other type and evaluations were repeated.

RESULTS

Significant differences were observed regarding psychological acceptance (appearance), time, hygiene, undergo procedures, recommend procedures and the overall experience. In contrast, insignificant difference was observed regarding speech, chewing capacity, restorative procedures, complications and information prior to treatment. No significant difference was reported when comparing chewing performance between the two types of bar attachment.

CONCLUSION

Within this clinical study limitations, patient satisfaction with zirconia bar was higher than Co-Cr bar in terms of appearance, time, hygiene, undergo procedures, recommend procedures and the overall experience. Zirconia can become a suitable alternative to cobalt chromium alloys as a bar attachment. Combining the advantages of implant supported overdenture, CAD/CAM zirconia bar as an attachment, a satisfactory non-metal prosthesis could be provided.

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.

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.

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.

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.

Masticatory performance analysis using photographic image of gummy jelly

PURPOSE

Masticatory performance can be measured through elution of glucose or beta-carotene from comminuted gummy jelly. However, these methods require special devices. Additionally, occasional/unintentional swallowing or inadequate collection of comminuted particles of gummy jelly in the oral cavity may cause measurement errors. Therefore, we devised a new photographic method to estimate the increase in surface area and weight of comminuted gummy jelly. This study aimed to verify the accuracy of this method.

METHODS

Initially, fifty images depicting the comminuted pieces in a special box were prepared. Then, the increase in surface area was measured using a fully-automated method, and the weight was measured. The size and angle of each image were adjusted based on markers located at the four corners of the box. From these photographic images, the area, perimeter, color average, color deviation, side area, and amount of surface roughness for each particle was calculated, and multiple regression analysis was performed to estimate the surface area and weight. The relationship between the estimated values and the values measured with the fully-automated device and by weight were analyzed.

RESULTS

The intra-class correlation coefficient between the estimated value and the value from the fully-automated method was r = 0.956. This high correlation was also obtained under different photographic conditions. Furthermore, for determining whether 80% or less gummy jelly was collected, the sensitivity was 100% and the specificity was 91%.

CONCLUSIONS

The newly developed photographic method is valuable because it is accessible and may assist in achieving reliable evaluation of masticatory performance.

The influence of habitual consumption of chewing gums in the outcome of masticatory performance tests using two-coloured chewing gums

The aim of this study is to assess the influence of regular consumption of chewing-gums on the Masticatory Performance (MP); and to determine if increasing the consumption improves the MP of non-regular consumers. We recorded the chewing-gums consumption rate (CGC) and measured the MP of 265 participants (µ = 47.09, σ = 22.49 years) using the Variance of the Histogram of the Hue (VhH) image processing method. Then, participants were instructed to increase the consumption, and the MP was measured again (SESSION) two and four days after. Normality of MP was verified with Kolmogorov-Smirnov and Shapiro-Wilk tests. The association between the age and the consumption rate was measured with GEE and the eta-squared statistic. Finally, a 3 × 3 mixed ANOVA with SESSION as the within-subject factor and CGC as the between-subjects factor was run. Session-wise and group-wise comparison were performed with post hoc Bonferroni. No systematic error was detected for VhH (p = 1.00). Kolmogorov-Smirnov and Shapiro-Wilk tests confirmed the normality of the distribution of MP (p > 0.05). There was a significant effect of SESSION on MP, F(1.746, 457.328) = 59.075, p < 0.001; furthermore, there were significant differences in MP between SESSIONs. Additionally, there was a significant effect of CGC on MP, with F (2, 356.53) = 564.73, p < 0.001. In conclusion, the chewing-gum consumption habits influence the two-coloured chewing gum mixing test. The apparent MP of non-regular consumers can be improved by prescribing a controlled increase in the consumption of chewing-gums for a few days.

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

The objectives of this study is to identify methods for objectively assessing masticatory performance (MP) and to evaluate their measurement properties. A secondary objective was to identify any reported adverse events associated with the methods to assess MP. Bibliographic databases were searched, including MEDLINE, Embase, Web of Science Core Collection, Cochrane, and Cinahl databases. Eligible papers that satisfied predefined inclusion and exclusion criteria were appraised independently by two investigators. Four other investigators independently appraised any measurement properties of the assessment method according to the consensus-based standards for the selection of health measurement instruments checklist. The qualities of the measurement properties were evaluated using predefined criteria. The level of evidence was rated by using data synthesis for each MP assessment method, where the rating was a product of methodological quality and measurement properties quality. All studies were quality assessed separately, initially, and subsequently for each method. Studies that described the use of identical assessment method received an individual score, and the pooled sum score resulted in an overall evidence synthesis. The level of evidence was synthesized across studies with an overall conclusion, that is, unknown, conflicting, limited, moderate, or strong evidence. Forty-six out of 9,908 articles were appraised, and the assessment methods were categorized as comminution (n = 21), mixing ability (n = 23), or other methods (n = 2). Different measurement properties were identified, in decreasing order construct validity (n = 30), reliability (n = 22), measurement error (n = 9), criterion validity (n = 6), and responsiveness (n = 4). No adverse events associated with any assessment methods were reported. In a clinical setting or as a diagnostic method, there are no gold standard methods for assessing MP with a strong level of evidence for all measurement properties. All available assessment methods with variable level of evidence require lab-intensive equipment, such as sieves or digital image software. Clinical trials with sufficient sample size, to infer trueness and precision, are needed for evaluating diagnostic values of available methods for assessing masticatory performance.

Characterization of oral tactile sensitivity and masticatory performance across adulthood

Texture perception is one of the most important factors in food acceptance, yet population-wide differences in texture sensations are not well understood. The variation in texture perception across populations is thought to depend on oral tactile sensitivity and masticatory performance. To address this hypothesis, we aimed to measure tactile acuity with a battery of tests and quantitate the relationship to masticatory performance. The study was performed on 98 participants, in three age groups (20-25, 35-45, or over 62). Two main measures of oral sensitivity were performed: to assess bite force, subjects were asked to discriminate between foam samples of varying hardness. Second, to assess lingual sensitivity the subjects were asked to identify 3D printed shapes using their tongue, as well as identify confectionary letters. Additionally, masticatory performance was measured through assessing each participants ability to mix two-colored chewing gum. In general, we found that sensitivity and masticatory performance in the younger age groups was superior to that of older adults. We also found a positive linear trend between bite force sensitivity and masticatory performance with younger participants, a trend not found in older participants. We found no significant relationship between age groups for bite force sensitivity and masticatory performance, suggesting that age-related declines in bite force sensitivity are not a significant cause of altered masticatory performance. This study represents a valuable first step in showing that bite force sensitivity does not depend on age, and the minimal influence of factors such as oral sensitivity on masticatory performance. PRACTICAL APPLICATIONS: In a society that is rapidly aging, it is important to understand the subtle changes in physiology and eating behavior that are associated with aging. This study used a variety of tests oral sensitivity to better understand which aspects of oral physiology are integral for effective chewing. The information gained helps shed light on to the factors that create an effective chewing cycle. Besides moving knowledge forward, this study may help in designing food and rehabilitation programs for those with trouble chewing and swallowing, increasing their overall quality of life.

Validation of a purpose-built chewing gum and smartphone application to evaluate chewing efficiency

OBJECTIVES

To validate a purpose-built two-coloured chewing gum (Hue-Check Gum^® ), and to test the accuracy of a custom-built smartphone application for a colour-mixing ability test to assess chewing function.

METHODS

Fully dentate participants (28D-group) and edentulous participants with implant overdentures (IOD-group) were recruited. They chewed a Hue-Check Gum^® for 5, 10, 20, 30 and 50 chewing cycles, respectively. Maximum voluntary bite force (MBF) was assessed with a digital gauge. The specimens were analysed according to their colour mixture (variance of hue, VOH) with a validated software (VOH_scan) and a newly developed smartphone application (VOH_app).

RESULTS

Participants segregated by dental state were significantly different regarding the number of occluding pairs of teeth, age and MBF. VOH_scan showed a negative logarithmic association with the number of chewing cycles, and VOH could be predicted from chewing cycles, MBF and gender. The clearest discrimination between the IOD and the 28D groups was observed for n = 20 chewing cycles; at this point, VOH was distinguishably different with a P-value < 0.0001. The VOH_app was a very good predictor for VOH_scan with 0.80 < pseudo-R²  < 0.83, depending on light exposure and measuring distance. There was, however, a systematic error in the accuracy of the app for inadequately chewed specimens.

CONCLUSIONS

The use of the two-coloured chewing gum would provide a fast, simple and inexpensive method for the assessment of masticatory performance, which could be used in geriatric wards or in private practices without the requirement of specialised equipment or trained staff.

Masticatory efficiency of implant-supported removable partial dental prostheses in patients with free fibula flap reconstructed mandibles: A split-mouth, observational study

OBJECTIVES

The aim of this split-mouth study was to evaluate the masticatory efficiency in patients with segmentally reconstructed mandibles using free fibula flaps, with and without stabilizing osteosynthesis material in-situ during implant placement for rehabilitation with implant-supported removable partial dental prostheses (ISRPDPs).

METHODS

Ten participants (n = 10; ♀ = 2, ♂ = 8; mean age = 38.1 years) consented to participate in this study. The participants' normal side (Side N) of the mandible served as the control side, for comparing the masticatory efficiency of the segmentally reconstructed and rehabilitated side (Side R). Masticatory efficiency was evaluated using the two-colored chewing gum test, measured as subjective assessment (SA) and electronically evaluated variance of hue (VOH). Data were checked for normal distribution and statistically analyzed with the level of significance set to p < 0.05.

RESULTS

Thirty-four tissue-level implants were placed in reconstructed mandibles of 10 participants. There was no significant difference observed in the masticatory efficiencies between Side N and Side R, in both subjective and electronic assessments. No implant loss was observed after a post-rehabilitated mean follow-up period of 42.7 months, revealing an implant survival rate of 100%.

CONCLUSIONS

In patients with surgically reconstructed mandibles, a normal masticatory function can be successfully achieved with a rehabilitation of the reconstructed side with implant-supported removable partial dental prostheses. Implant-supported prostheses should be actively advocated in patients with reconstructive surgeries to restore their masticatory function, extend their food choices, and improve their overall oral health-related quality of life.

Reliability of a two-colour chewing gum test to assess masticatory performance in complete denture wearers

The aim of this study was to test the reliability of a method to measure the masticatory performance of complete denture wearers employing a colour-mixing ability test and assessment by visual and electronic colourimetric analysis. A sample of 75 subjects was selected from patients who received new conventional complete dentures. Masticatory tests were performed using a two-colour chewing gum that was masticated for 5, 10, 20, 30 and 50 chewing cycles, performed in a random order. The mixing level of the two colours of the chewed gum was assessed visually by two independent raters based on a 5-point ordinal scale. The specimens were flattened into a 1-mm-width wafer, scanned and saved as a two-sided digital image. Each pair of images was submitted to an electronic colourimetric analysis to assess the level of colour mixture, measured by the circular variance of hue (VOH). Overall inter- and intra-rater agreements in visual analysis were 64% and 68%, respectively (almost 99% of scores ranged within ±1 point), whilst overall weighted kappa was >0.80. A proportional increase in the level of mixture occurred with increased number of chewing cycles (P < .001). Similarly, VOH and the visual analysis were highly correlated (r = -.89; P < .001). Bland-Altman plots revealed excellent agreement and extremely low systematic error between duplicated VOH measures. It was concluded that the two-colour chewing gum test is a reliable method to assess the masticatory performance in complete denture wearers using both visual and electronic colourimetric analyses.

A novel expert system for objective masticatory efficiency assessment

Most of the tools and diagnosis models of Masticatory Efficiency (ME) are not well documented or severely limited to simple image processing approaches. This study presents a novel expert system for ME assessment based on automatic recognition of mixture patterns of masticated two-coloured chewing gums using a combination of computational intelligence and image processing techniques. The hypotheses tested were that the proposed system could accurately relate specimens to the number of chewing cycles, and that it could identify differences between the mixture patterns of edentulous individuals prior and after complete denture treatment. This study enrolled 80 fully-dentate adults (41 females and 39 males, 25 ± 5 years of age) as the reference population; and 40 edentulous adults (21 females and 19 males, 72 ± 8.9 years of age) for the testing group. The system was calibrated using the features extracted from 400 samples covering 0, 10, 15, and 20 chewing cycles. The calibrated system was used to automatically analyse and classify a set of 160 specimens retrieved from individuals in the testing group in two appointments. The ME was then computed as the predicted number of chewing strokes that a healthy reference individual would need to achieve a similar degree of mixture measured against the real number of cycles applied to the specimen. The trained classifier obtained a Mathews Correlation Coefficient score of 0.97. ME measurements showed almost perfect agreement considering pre- and post-treatment appointments separately (κ ≥ 0.95). Wilcoxon signed-rank test showed that a complete denture treatment for edentulous patients elicited a statistically significant increase in the ME measurements (Z = -2.31, p < 0.01). We conclude that the proposed expert system proved able and reliable to accurately identify patterns in mixture and provided useful ME measurements.

Oral tactile sensitivity and masticatory performance are impaired in stroke patients

Oro-facial impairment following stroke frequently involves reduced chewing performance, that is oral phase dysphagia. The aim was to investigate the sensitivity of oral tissues following stroke and its potential impact on masticatory function. Therefore, hospitalised post-stroke patients were recruited and compared to healthy controls. Outcome measures comprised masticatory performance employing a colour-mixing ability, that is a bolus-kneading test, maximum lip- and bite force and the one-point and two-point tactile thresholds. Food hoarding and prevalence of dry mouth were evaluated with ordinal scales. Twenty-seven stroke patients (age 64·3 ± 14·1 years) and 27 healthy controls (age 60·8 ± 14·3 years, P = 0·254) participated in this study. The groups had similar numbers of occluding units. Stroke patients reported more frequently dry mouth sensations and food hoarding. The intra-oral tactile sensitivity on the contra-lesional side was significantly lower in stroke patients compared to controls (0·0001 < P < 0·0002), and significant intra-group side differences were found only in the stroke group (0·0001 < P < 0·0010). For the lip, both sides were less sensitive in the stroke group compared with controls. The experiments confirmed lower masticatory performance and lip force in the stroke group, but the bite force was similar compared to healthy controls. Oral sensitivity was correlated with masticatory performance when a global correlation model was applied. A stroke may affect the sensitivity of the intra-oral tissues contra-lesionally, thus potentially affecting chewing function. Rehabilitation should therefore not only focus on motor impairment, but equally stimulate the sensitivity of the oral tissues, employing dry ice application or similar specific treatments.

Immediate versus delayed loading of strategic mini dental implants for the stabilization of partial removable dental prostheses: a patient cluster randomized, parallel-group 3-year trial

Background

Acceptable short-term survival rates (>90 %) of mini-implants (diameter < 3.0 mm) are only documented for mandibular overdentures. Sound data for mini-implants as strategic abutments for a better retention of partial removable dental prosthesis (PRDP) are not available.

Methods/design

The purpose of this study is to test the hypothesis that immediately loaded mini-implants show more bone loss and less success than strategic mini-implants with delayed loading. In this four-center (one university hospital, three dental practices in Germany), parallel-group, controlled clinical trial, which is cluster randomized on patient level, a total of 80 partially edentulous patients with unfavourable number and distribution of remaining abutment teeth in at least one jaw will receive supplementary min-implants to stabilize their PRDP. The mini-implant are either immediately loaded after implant placement (test group) or delayed after four months (control group). Follow-up of the patients will be performed for 36 months. The primary outcome is the radiographic bone level changes at implants. The secondary outcome is the implant success as a composite variable. Tertiary outcomes include clinical, subjective (quality of life, satisfaction, chewing ability) and dental or technical complications.

Discussion

Strategic implants under an existing PRDP are only documented for standard-diameter implants. Mini-implants could be a minimal invasive and low cost solution for this treatment modality.

Trial registration

The trial is registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00007589 (www.germanctr.de) on January 13^th, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-016-0259-z) contains supplementary material, which is available to authorized users.

Assessment of masticatory performance by means of a color-changeable chewing gum

PURPOSE

Previous research determined the relevance of masticatory performance with regard to nutritional status, cognitive functions, or stress management. In addition, the measurement of masticatory efficiency contributes to the evaluation of therapeutic successes within the stomatognathic system. However, the question remains unanswered as to what extent modern techniques are able to reproduce the subtle differences in masticatory efficiency within various patient groups. The purpose of this review is to provide an extensive summary of the evaluation of masticatory performance by means of a color-changeable chewing gum with regard to its clinical relevance and applicability.

STUDY SELECTION

A general overview describing the various methods available for this task has already been published. This review focuses in depth on the research findings available on the technique of measuring masticatory performance by means of color-changeable chewing gum. Described are the mechanism and the differentiability of the color change and methods to evaluate the color changes. Subsequently, research on masticatory performance is conducted with regard to patient age groups, the impact of general diseases and the effect of prosthetic and surgical treatment.

RESULTS

The studies indicate that color-changeable chewing gum is a valid and reliable method for the evaluation of masticatory function.

CONCLUSION

Apart from other methods, in clinical practice this technique can enhance dental diagnostics as well as the assessment of therapy outcomes.