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.

Determination of the occlusal vertical dimension in edentulous patients using lateral cephalograms.

The determination of the occlusal vertical dimension (OVD) in edentulous patients is based on clinical assessment with high variability. This study tested the hypothesis: The average OVD in edentulous patients with conventional dentures is too low compared to orthodontic norms, when only clinical parameters are used for the determination of the OVD. Edentulous patients with conventional full dentures were enrolled. Clinical parameters were judged by two senior prosthodontists. Digital lateral cephalograms were taken and served to calculate the OVD according to the lower face height angle (ANS-Xi-D) taking tooth-independent facial growth patterns into account. The ANS-Xi-D angle was compared with reference values by applying one-sample mean comparison tests. Thirty-six participants (17 female, 19 male; mean age 65.3 ± 10.6 years) were enrolled in this study. Clinically, the OVD of four dentures was judged too low, in one case too high, and in the other 31 cases as correct. The mean ANS-Xi-D angle was 48.28°±4.86 and statistically not different to the norm value of 49°±4 (n.s.). There was a tendency that the ANS-Xi-D angle was different between participants with different tooth-independent facial growth patterns (ANOVA, P = .0548). Predominantly, clinically sufficient prostheses show adequate ANS-Xi-D angles. Short-face type denture patients are often restored to comply with mesiofacial norms. The determination of the OVD based on lateral cephalography is not recommendable to be a standard diagnostic parameter. Orthodontic norms are derived from dentate cohorts and might not take the continuing facial growth and other confounding factors of edentulous subjects into account.

Oro-facial impairment in stroke patients.

Stroke is considered one of the leading causes of death and acquired disability with a peak prevalence over the age of 80 years. Stroke may cause debilitating neurological deficiencies that frequently result in sensory deficits, motor impairment, muscular atrophy, cognitive deficits and psychosocial impairment. Oro-facial impairment may occur due to the frequent involvement of the cranial nerves' cortical representation areas, central nervous system pathways or motoneuron pools. The aim of this narrative, non-systematic review was to discuss the implications of stroke on oro-facial functions and oral health-related quality of life (OHRQoL). Stroke patients demonstrate an impaired masticatory performance, possibly due to reduced tongue forces and disturbed oral sensitivity. Furthermore, facial asymmetry is common, but mostly discrete and lip restraining forces are reduced. Bite force is not different between the ipsi- and contra-lesional side. In contrast, the contra-lesional handgrip strength and tongue-palate contact during swallowing are significantly impaired. OHRQoL is significantly reduced mainly because of the functional impairment. It can be concluded that impaired chewing efficiency, dysphagia, facial asymmetry, reduced lip force and OHRQoL are quantifiable symptoms of oro-facial impairment following a stroke. In the absence of functional rehabilitation, these symptoms seem not to improve. Furthermore, stroke affects the upper limb and the masseter muscle differently, both, at a functional and a morphological level. The rehabilitation of stroke survivors should, therefore, also seek to improve the strength and co-ordination of the oro-facial musculature. This would in turn help improve OHRQoL and the masticatory function, subsequently preventing weight loss and malnutrition.

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.

Palatal morphology changes in post-stroke patients measured by geometric morphometrics.

This study aimed to describe longitudinal palatal shape changes in post-stroke patients when compared to a sample of healthy subjects through linear measurements and geometric morphometrics. The 3D palatal scanned models of seven stroke patients having a 1-year post-stroke follow-up were matched with seven control subjects of the same age group (range 50-87 years). Intercanine, intermolar distances and palatal height were measured. 3D images were also analysed through geometric morphometrics to assess changes in the shape of the palate from T0 to T1 (1 year after the stroke). Principal component analysis was used to describe shape morphology changes, and visual colour maps were used to qualitatively assess differences between T0 and T1. No changes were detected nor in linear measures neither in palatal shape in healthy subjects from T0 to T1. The palates of stroke patients showed no linear differences either. However, when visualising shape changes through colour maps, the lateral aspects of the palatal vault were slightly narrower in T1, with respect to T0 in stroke patients. This may be attributed to altered tongue function following the stroke.

Impact of lingual plates on the interocclusal free way space: a pilot study.

Palatal augmentation prostheses are commonly used in the treatment for dysphagia. By lowering the palatal contours, the tongue contact is increased and thus the bolus propulsion facilitated. However, the unfavourable weight of such appliances may be avoided when using lingual plates. Hence, the aim of this study is to investigate the effect of two different types of lingual plates on the vertical dimension in rest position. Eleven healthy dentate subjects with an average age of 35.5 years (26-60 years) volunteered in this pilot study. The vertical overbites were measured on plaster models. Two different designs of the experimental lingual plates were tested in this pilot study (P-type & D-type). The inter-occlusal freeway space was measured using the electromagnetic K7 jaw-tracking system (Myotronics, U.S.A.), while the subjects were seated in an upright position. They were asked to close from rest position into maximum intercuspation for about 2 s. Recordings were performed without the plates and subsequently with each of the two plate designs in situ. All recordings were performed three times and the second closing movement of each recording was used for the analysis. After averaging the repetitions without experimental lingual plates, with P-type and D-type plates, the differences were analysed using a Kruskall-Wallis test. The results showed no significantly increased freeway space while using both types of lingual plates. Hence, it can be concluded that any altered tongue pressure during swallowing with lingual plates is not related to an increase in vertical dimension.

The effect of food bolus location on jaw movement smoothness and masticatory efficiency.

Masticatory efficiency in individuals with extensive tooth loss has been widely discussed. However, little is known about jaw movement smoothness during chewing and the effect of differences in food bolus location on movement smoothness and masticatory efficiency. The aim of this study was to determine whether experimental differences in food bolus location (anterior versus posterior) had an effect on masticatory efficiency and jaw movement smoothness. Jaw movement smoothness was evaluated by measuring jerk-cost (calculated from acceleration) with an accelerometer that was attached to the skin of the mentum of 10 asymptomatic subjects, and acceleration was recorded during chewing on two-colour chewing gum, which was used to assessed masticatory efficiency. Chewing was performed under two conditions: posterior chewing (chewing on molars and premolars only) and anterior chewing (chewing on canine and first premolar teeth only). Jerk-cost and masticatory efficiency (calculated as the ratio of unmixed azure colour to the total area of gum, the unmixed fraction) were compared between anterior and posterior chewing with the Wilcoxon signed rank test (two-tailed). Subjects chewed significantly less efficiently during anterior chewing than during posterior chewing (P = 0·0051). There was no significant difference in jerk-cost between anterior and posterior conditions in the opening phase (P = 0·25), or closing phase (P = 0·42). This is the first characterisation of the effect of food bolus location on jaw movement smoothness at the same time as recording masticatory efficiency. The data suggest that anterior chewing decreases masticatory efficiency, but does not influence jerk-cost.

Clinical outcomes of different implant types in mandibular bar-retained overdentures: a retrospective analysis with up to 20 years follow-up.

PURPOSE: To determine the clinical and radiological outcomes of hybrid-design- (HD) and bone-level (BL) implants for bar-retained mandibular implant-overdentures (IODs). METHODS: For this retrospective study, edentulous patients who had received maxillary complete dentures and mandibular bar-retained IODs were invited for a follow-up assessment. Implant survival, implant success and health of peri-implant tissues were assessed on an implant level-based analysis. Patient-based parameters served to identify risk factors for peri-implant bone loss, presence of peri-implantitis and success. RESULTS: Eighty patients (median age 72.72 [67.03; 78.81] years, 46 females) with 180 implants (median follow-up 12.01 [10.82; 21.04] years) were assessed. There was no difference concerning the rate of implant failure (p = 0.26), or peri-implantitis (p = 0.97) between HD and BL implants. Solely in one study group, there was the presence of peri-implant pus. Implant success was higher in BL implants with one group being notably higher than the comparing groups (p = 0.045). For bone loss, a width of keratinized mucosa (KM) ≤ 1 mm (p = 0.0006) and the presence of xerostomia (p = 0.09) were identified as risk factors. Smoking (p = 0.013) and a higher body mass index (BMI) (p = 0.03) were a risk factor for peri-implantitis. As risk factors for reduced implant success, a small width of KM (p = 0.003) and the presence of xerostomia (p = 0.007) were identified. CONCLUSIONS: For mandibular bar-retained IODs, both BL and HD implants are mostly successful. A minimum of 1 mm KM around implants and normal salivary flow are relevant factors for implant success and stable peri-implant bone levels. Smoking and a high BMI are potential risk factors for peri-implantitis.

Global prevalence of edentulism and dental caries in middle-aged and elderly persons: A systematic review and meta-analysis.

OBJECTIVE: The aim of the study was to analyze data collected from studies worldwide on the prevalence of edentulism and dental caries, in community-dwellers aged ≥ 45 years. DATA: Inclusion criteria; participants aged ≥ 45 years, community-dwellers. Exclusion criteria; participants aged < 45 years, in nursing homes, data obtained from dental clinics or pre-2005. The quality assessment tool by The National Heart, Lung and Blood Institute for Observational Cohort and Cross-sectional studies was used. Meta-analysis using the random-effects model (95% confidence interval) was done with data on participants who were edentulous and/or had active dental caries and stratified by regions of the world, age and Gross National Income per capita. Limitations in the data arose from several factors such as design of the studies included differences in socioeconomic status and access to health care among different countries. SOURCES: Embase, MEDLINE via Pubmed and Scopus, manual searches, from January 2016, restricted to English. Experts from different countries were contacted to identify National oral health surveys (NOHS) conducted from 2010 onwards. STUDY SELECTION: Eighty-six papers and seventeen NOHS were selected for data extraction. Majority of the studies (n = 69) were cross-sectional and of fair quality. 1.1%-70%, 4.9% - 98% prevalence of edentulism and dental caries, respectively. 22%, 45% estimated random-effects pooled prevalence of edentulism and dental caries, respectively. CONCLUSIONS: Within the limitations of this study, the findings indicate that untreated dental caries and tooth loss are prevalent on a global level with wide variations among different countries, age groups and socioeconomic status. CLINICAL SIGNIFICANCE: The findings demonstrate the reality of the new cohort of older adults, with higher tooth retention implying more dental caries incidence and the need for different care strategies to ensure better oral health. Large variations and difficulty in making comparisons among different countries highlight the need for more standardized, regular research.

Masseter muscle thickness in hospitalised stroke patients.

The aim of the study was to investigate the thickness of the masseter muscles in stroke patients when compared to a control group (CG). Hospitalised stroke patients (18 men, 13 women; age 69.0 +/- 12.7 years) were compared to a CG (13 men, 11 women; age 68.8 +/- 10.8 years) composed to correspond to in age, gender and dental state. The thickness of the masseter muscle was recorded by means of a real-time ultrasound scanner on both sides, twice under contraction and twice in relaxed condition. In the stroke patients, the thickness of the masseter muscle of the affected side (aff) was smaller than the one of the non-affected side (non-aff) both, under contraction (aff 13.1 +/- 2.4 mm; non-aff 13.8 +/- 2.3 mm, P

A comparative study of 2 fluoride-based mouthrinses.

OBJECTIVE: The purpose of this study was to compare the effectiveness of 2 mouthrinses (conventional Meridol and alcohol-free Meridol). METHOD AND MATERIALS: A controlled, single-blind clinical study of 3 weeks' duration was conducted on 80 adult subjects in good general health and without severe periodontitis (probing depths no deeper than 4 mm). The mouthrinses supplemented regular measures of oral hygiene for the reduction of plaque and gingivitis. In preliminary examinations to determine general conditions of oral health, especially the level of plaque, gingivitis, and periodontal findings, the approximal plaque index, sulcular bleeding index, and gingival index were established for each subject. Afterward the subjects were provided with a professional toothcleaning, as required. Each subject was randomly provided with 1 of the 2 mouthrinses, to be used 3 times daily in addition to routine oral health measures. The 3 indexes were reevaluated after 3 weeks; in addition, an optional stain index was employed. RESULTS: In both subject groups, a statistically significant reduction in plaque accumulation, as well as a reduction in inflammation and the tendency to bleeding, was observed. Reversible staining of the teeth and tongue was observed in fewer than one third of the subjects in both groups. CONCLUSION: Comparison of the 2 Meridol mouthrinses revealed no difference in effectiveness related to the alcohol content.

Implant-supported mandibular overdentures in very old adults: a randomized controlled trial.

The purpose of this study was (1) to investigate denture satisfaction following the conversion of existing mandibular complete dentures to implant overdentures (IOD) in very old edentulous patients who depend on help for activities of daily living and (2) to evaluate secondary end points, such as functional, structural, nutritional, and patient-centered aspects. For this randomized clinical trial, 2 interforaminal short implants were placed in the intervention group (n = 16, 85.0 ± 6.19 yrs) to retain mandibular IODs; the control group (n = 18, 84.1 ± 5.55 yrs) received conventional relines. During the first year, no implant was lost; however, 2 patients died. IODs proved more stable, and participants in the intervention group demonstrated significantly higher denture satisfaction as well as an increased oral health-related quality of life compared to the control group. Maximum voluntary bite force improved significantly with IODs, yet the chewing efficiency was not different between groups. Masseter muscle thickness increased with IODs, mainly on the preferred chewing side. Body mass index decreased in both groups, but the decline tended to be smaller in the intervention group; blood markers and the Mini Nutritional Assessment did not confirm this tendency. These results indicate that edentulous patients who depend on help for activities of daily living may benefit from IODs even late in life.

Masticatory function and bite force in stroke patients.

Orofacial functions are frequently affected by stroke, but little is known on the nature and extent of the impairment of mastication, which is investigated in this observational study. Thirty-one stroke patients, aged 69.0 ± 12.7 yrs, presenting with a hemi-syndrome with facial palsy, were recruited. Chewing efficiency, maximum bite and restraining lip forces were tested. Stroke severity (National Institutes of Health Stroke Scale) and dental state were recorded. The control group was similar in age, gender, and dental state (n = 24). The chewing efficiency was significantly lower in the stroke group (p ≤ 0.0001) and was related to both the dental state and the lip forces measured with small and medium-sized labial plates. The maximum bite force proved to be not significantly different between sides or groups (n.s.), whereas lip force was significantly lower in the stroke group (p ≤ 0.05). Chewing efficiency is severely affected by stroke; thus, rehabilitation protocols should aim to restore the strength and co-ordination of the orofacial muscles.

Carotid artery calcification in ischemic stroke patients detected in standard dental panoramic radiographs - a preliminary study.

PURPOSE: Examine the prevalence of carotid artery calcifications in standard dental panoramic radiographs (OPT), their association to gender, medical history and oral status. Assess the predictive value of a dental OPT in early diagnosis of carotid artery calcifications. MATERIAL AND METHODS: Fourteen patients admitted to Geneva University Hospital for recent ischemic stroke and stenosis of the carotid artery confirmed by Duplex sonography. All OPTs were digitised and subsequently assessed independently by two operators. RESULTS: From 21 carotid artery calcifications detected with Doppler sonography 15 were visible on the corresponding OPT, most of them on the right side (n=11). No correlation was found between the side of calcification and cerebral lesion. Hypertension and periodontal disease were the most prevalent cardiovascular risk factors. CONCLUSIONS: Dentists who either detect carotid artery calcifications in OPTs or see patients with severe periodontitis should consider a prophylactic specialist examination.

A two-colour chewing gum test for masticatory efficiency: development of different assessment methods.

OBJECTIVE: The aim of this study was to investigate different assessment methods of a two-colour chewing gum test for masticatory efficiency to determine its validity for research and clinical purposes. MATERIALS AND METHODS: Twenty adult volunteers, eleven women and nine men (mean age of 27.5 years), participated in this study. All participants perceived their masticatory efficiency as normal. The task was to chew five samples of a two-colour chewing gum for 5, 10, 20, 30 and 50 cycles respectively. Maximum bite force was measured. All samples were assessed twice by two independent operators both, as 'bolus' and after flattening to 1 mm thick 'wafers'. The latter were scanned and the unmixed pixels counted using Adobe Photoshop Elements to calculate the ratio of unmixed colour to the total surface. RESULTS: Digital image processing confirmed a significant correlation between colour mixing and chewing duration (P < 0.001). Subjective assessment proved less accurate with fair to substantial intra-examiner agreement for 'bolus' (0.20 < kappa < 0.63) and substantial to almost perfect agreement for 'wafer' (0.60 < kappa < 0.88). Inter-examiner agreement was consistently moderate or substantial only for specimen chewed 20 cycles or longer. No significant correlation was found between the colour mixture and the maximum bite force. CONCLUSION: Digital image processing of the two-colour chewing gum test specimen provides reliable quantitative data for chewing efficiency. Visual assessments were less reliable but might still be useful in screening for chewing deficiencies in a clinical setting. In this context, the test should be performed with a flattened specimen chewed, probably for 20 cycles.