Efficacy of a stannous fluoride dentifrice for relieving dentinal hypersensitivity in Chinese population: an 8-week randomized clinical trial.

OBJECTIVES: To compare the effectiveness of using a 0.454% stannous fluoride-containing dentifrice twice daily in relieving dentinal hypersensitivity (DH) in a Chinese population. MATERIALS AND METHODS: This was a single-centre, randomized, controlled, examiner-blind, three-treatment-arm, parallel-group study in participants with clinically diagnosed DH. Subjects who met inclusion criteria (n = 197) were randomly allocated into 3 groups: test group (n = 66)-using a 0.454% stannous fluoride-containing dentifrice twice daily; positive control group (n = 64)-using a 5.0% calcium sodium phosphosilicate-containing dentifrice twice daily; negative control group (n = 67)-using a 1150 ppm of NaF dentifrice twice daily. Status of DH was assessed at week 4 and week 8 by the same independent examiner. Changes from baseline in Schiff sensitivity score, tactile threshold and Dentine Hypersensitivity Experience Questionnaire (DHEQ) score were analysed using analysis of covariance models. The DHEQ evaluated subject-perceived oral health-related quality of life (OHRQoL). RESULTS: Statistically significant improvements in mean Schiff scores (p < 0.0001 for all products at Weeks 4 and 8), tactile threshold (p < 0.0001 for test and negative control at Weeks 4 and 8: Week 4 p = 0.0040 and Week 8 p < 0.0001 for positive control) and all DHEQ scores (p < 0.01 for all groups) were observed. No statistically significant differences were observed in the adjusted mean between all dentifrices at both timepoints, potentially driven by a placebo effect. Forty-two treatment-emergent adverse events (TEAEs) were reported (n = 32 subjects), with 2 serious AEs (n = 1) in the test group. TEAEs were not considered treatment-related. CONCLUSIONS: All groups demonstrated statistically significant improvements in Schiff score, tactile threshold and OHRQoL. However, due to a possible placebo effect in the negative control, there were no statistically significant differences between the dentifrices. CLINICAL RELEVANCE: This study adds to the growing research exploring why the placebo effect is a common phenomenon in DH studies. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04950465.

A Randomized Clinical Study to Evaluate the Efficacy of an 8% (w/w) Strontium Acetate Dentifrice in Providing Relief from Dentinal Hypersensitivity.

OBJECTIVES: To evaluate the clinical efficacy of a dentifrice containing 8% strontium acetate in the relief of dentinal hypersensitivity (DH), compared with that of a standard fluoride dentifrice, in a Chinese population. METHODS: This was an eight-week, single-center, randomized, controlled, examiner-blind, parallel-group study in healthy adult volunteers with DH. After an initial acclimatization period, subjects were randomized to receive either a test dentifrice containing 8% strontium acetate with 1040 ppm fluoride as sodium fluoride, or a commercially available regular fluoride dentifrice containing 1400 ppm fluoride as sodium monofluorophosphate with no known anti-sensitivity activity (negative control). The subjects were instructed to brush twice daily with their allocated dentifrice for the next eight weeks. DH was assessed at baseline and following four and eight weeks of dentifrice use by response to a tactile stimulus (tactile threshold) and evaporative (air) stimulus (Schiff Sensitivity Scale). RESULTS: A total of 135 subjects were randomized to study treatment and 133 completed the study. Both the test and negative control dentifrices were associated with statistically significant reductions in sensitivity from baseline after four and eight weeks' treatment, as assessed by the Schiff sensitivity score (all p ≤ 0.0002) and tactile threshold (all p < 0.0001). The reductions in Schiff sensitivity scores were statistically significantly greater in the test dentifrice group compared with the negative control group, with mean between-treatment differences of 40.1% and 55.8% after four and eight weeks, respectively (both p < 0.0001). Although increases in the tactile threshold were greater in the test dentifrice group after four and eight weeks' treatment compared with the negative control group (mean difference of 13.7% and 14.2%, respectively), the two groups were not statistically significantly different. Both study dentifrices were generally well tolerated. CONCLUSIONS: In this study in a Chinese population, both the 8% strontium acetate dentifrice and the negative control dentifrice were associated with statistically significant reductions in DH from baseline after four and eight weeks of twice-daily brushing. A statistically significant difference was observed between the test dentifrice and the negative control in evaporative (air) sensitivity (Schiff sensitivity score) after four and eight weeks, favoring the test dentifrice.

Tactile sensitivity on the hands skin in rheumatic patients.

INTRODUCTION: Clinical symptoms of rheumatic diseases can cause changes in the level of skin tactile sensitivity. AIM: To determine the tactile threshold of the hands in female patients with rheumatic diseases. It also attempted to determine correlations between rheumatic patients' tactile sensitivity and the degree of articular movement limitations, the Barthel Index (BI) and Edinburgh Handedness Inventory (EHI) results, the level of disability of the right hand and the left hand as well as age, education and eyesight. MATERIAL AND METHODS: Ninety-nine female rheumatic patients aged 19-87 years took part in the study. The control group comprised 45 healthy women aged 23-80 years. The measurement of the tactile threshold was performed using the Touch-Test™ Sensory Evaluators (Semmes-Weinstein Monofilaments Test). The tactile threshold was measured at three sites on the hand: the little finger, the index finger and the metacarpus. RESULTS: The patients' tactile sensitivity ranges were classified as normal, diminished light touch and diminished protective touch. The degree of their disability was correlated with tactile sensitivity. The patients' tactile sensitivity worsens with age, but it is not correlated with the level of education. The lateralization was similar to that of the control group and was not correlated with tactile sensitivity. The worsening eyesight, independent of rheumatic disease, corresponds, however, with decreasing tactile sensitivity. CONCLUSIONS: The patients represented a group with a medium level of functional disability and lower tactile sensitivity.

Effect of cross-cultural differences on thickness, firmness and sweetness sensitivity.

Sensitivity of the somatosensory system may be influenced by multiple physiological parameters. Variations in oral physiology can arise from cross-cultural differences which may potentially affect sensory sensitivity. The aim of this case study was to quantify texture and taste sensitivity in Dutch (Caucasian) and Chinese (Asian) adults living in the Netherlands. Eighty-five healthy subjects were recruited including 44 Dutch (Caucasian) adults (29 females, 22.8 ± 2.3 yrs) and 41 Chinese (Asian) adults (30 females, 24.5 ± 2.1 yrs) living in the Netherlands for less than 1 year. Three sets of stimuli were used to quantify sensitivity of thickness (maltodextrin solutions differing in viscosity), firmness (agar gels differing in fracture stress) and sweetness (sucrose solutions differing in concentration). The 2-Alternative Forced Choice (2-AFC) ascending staircase method was used to determine texture and taste sensitivity. Unstimulated and stimulated saliva flow rate, fungiform papillae density (FPD), lingual tactile threshold and PROP taster status were determined and are referred to as physiological and sensory consumer characteristics. No significant differences were observed between Chinese and Dutch adults for thickness (Dutch 2.60 mPas, Chinese 2.19 mPas), firmness (Dutch 10.5 kPa, Chinese 10.3 kPa) and sweetness sensitivity (Dutch 0.012 g/mL, Chinese 0.017 g/mL). No significant differences were observed between Chinese and Dutch adults for saliva flow rate, lingual tactile threshold and PROP taster status. The relationships between the three sensory sensitivities (thickness, firmness, sweetness) and five physiological and sensory consumer characteristics (unstimulated and stimulated saliva flow rate, FPD, lingual tactile threshold, PROP taster status) were analyzed. Only one out of 15 relationships, firmness sensitivity and FPD, was significantly and weakly related suggesting that inter-individual variation in these consumer characteristics is almost unrelated to sensory sensitivity. We conclude that in this case study thickness, firmness and sweetness sensitivities do not differ between Dutch and Chinese adults living in the Netherlands. Saliva flow rate, fungiform papillae density, lingual tactile threshold and PROP taster status do not explain inter-individual variation in sensory sensitivity between these consumers.

Cathodal tDCS on the motor area decreases the tactile threshold of the distal pulp of the hallux.

Transcranial direct current stimulation (tDCS) has been reported to modulate cortical excitability. Most studies on this topic addressed the modulation effects of tDCS on the upper extremities. Foot-sole tactile sensation is essential to gait, but little is known about the effect of tDCS on sensory function in the foot area. Here we administered tDCS to 10 healthy adults, and we observed that the modulation effects of cathodal tDCS on the left motor area led to a decrease in the tactile threshold of the left center of the distal pulp of the hallux. This effect was not observed in the sham condition. In addition, the subjects' vigilance levels were not changed between before and after the tDCS. These results suggest that sensation on the sole of the left foot could be modulated by cathodal tDCS on the left motor area.

The Repetitive Mechanical Tactile Stimulus Intervention Effects Depend on Input Methods.

Elderly and stroke patients often have low spatial two-point discrimination function. The intervention effect of repetitive mechanical tactile stimulation has been shown to improve the spatial two-point discrimination function. The methods of tactile input are classified as either Active Touch or Passive Touch. In Passive Touch, the tactile stimulus is passively applied on the skin without voluntary movement, whereas in Active Touch, it is applied with voluntary movement. Based on the method of tactile input, tactile stimulation activate different cerebral cortex areas. A previous study reported that the tactile stimulation with Active Touch activate posterior parietal cortex, activated during a spatial two-point discrimination task. Therefore, the present study aimed to investigate the effects of two mechanical tactile stimulation intervention methods on two-point discrimination: tactile stimulation with voluntary movement (Active Touch) and without voluntary movement (Passive Touch). We recruited 15 healthy volunteers aged 20-23 years and applied tactile stimuli on their right index finger for 10 min. The mechanical tactile stimulator comprised 24 tiny plastic pins driven by piezoelectric actuators. In the Active Touch intervention, the pin was rubbed by voluntary movement of the right index finger (abduction 0°-10°) after the appearance of 12 pins. The Passive Touch intervention stimulated the index finger with the 12 pins setting at the centre of index finger. Tactile thresholds were measured using a two-point discrimination measurement device. Two-point discrimination threshold showed significant reduction after Active Touch intervention compared with those pre-intervention (Pre). Two-point discrimination threshold were not significantly modulated after Passive Touch intervention; however, significant negative correlation was observed between the intervention effect on two-point discrimination threshold and the performance Pre. This study suggesting that the effects of repetitive mechanical tactile stimulation depend on the method of tactile input. An effective intervention for improving two-point discrimination threshold is the application of Active Touch condition for 10 min.

Tactile recovery assessment with shortened Semmes-Weinstein monofilaments in patients with buccinator myomucosal flap oral cavity reconstructions.

BACKGROUND: The sensitive restoration is a primary aim of oral reconstructive surgery. The Semmes-Weinstein monofilament test is the "Gold Standard" to assess the threshold of tactile sensitivity on the skin but its use in the oral cavity is limited due to the size of the tools. We adopted half-cut Semmes-Weinstein monofilaments to evaluate the threshold of tactile sensitivity in oral reconstructions with buccinator myomucosal flaps. MATERIALS AND METHODS: Monofilaments were half-cut and recalibrated. Fifty-seven oral reconstructions were considered at 4-year minimum follow-up. Test was conducted both on the reconstructive flap and on the non-operated contralateral side. RESULTS: All of the considered flaps (100%) showed a recovery of tactile sensitivity. The overall average tactile threshold value assessed on this sample was 0.76 ± 1.58 g/mm2 overall. CONCLUSIONS: Shortened monofilaments allow easily assessment of tactile sensitivity in all the oral cavity areas, even in operated patients which often present lockjaw or microstomia.

Pain sensitivity and tactile spatial acuity are altered in healthy musicians as in chronic pain patients.

Extensive training of repetitive and highly skilled movements, as it occurs in professional classical musicians, may lead to changes in tactile sensitivity and corresponding cortical reorganization of somatosensory cortices. It is also known that professional musicians frequently experience musculoskeletal pain and pain-related symptoms during their careers. The present study aimed at understanding the complex interaction between chronic pain and music training with respect to somatosensory processing. For this purpose, tactile thresholds (mechanical detection, grating orientation, two-point discrimination) and subjective ratings to thermal and pressure pain stimuli were assessed in 17 professional musicians with chronic pain, 30 pain-free musicians, 20 non-musicians with chronic pain, and 18 pain-free non-musicians. We found that pain-free musicians displayed greater touch sensitivity (i.e., lower mechanical detection thresholds), lower tactile spatial acuity (i.e., higher grating orientation thresholds) and increased pain sensitivity to pressure and heat compared to pain-free non-musicians. Moreover, we also found that musicians and non-musicians with chronic pain presented lower tactile spatial acuity and increased pain sensitivity to pressure and heat compared to pain-free non-musicians. The significant increment of pain sensitivity together with decreased spatial discrimination in pain-free musicians and the similarity of results found in chronic pain patients, suggests that the extensive training of repetitive and highly skilled movements in classical musicians could be considered as a risk factor for developing chronic pain, probably due to use-dependent plastic changes elicited in somatosensory pathways.