BACKGROUND: This study aimed to evaluate the efficacy and safety of dentin hypersensitivity (DH) treatment using a newly developed device based on a powder jet deposition (PJD) technique that creates a hydroxyapatite (HAP) layer on the dentin surface, thereby alleviating the hypersensitivity. The effect of the PJD treatment was compared with that of conventional treatment using Teethmate Desensitizer (TMD; calcium-phosphate containing material with TTCP (Ca4(PO4)2O) and DCPA (CaHPO4)), which has been used clinically in Japan with well-confirmed effectiveness. MATERIALS AND METHODS: A randomized controlled trial was conducted including 35 patients who had symptoms of DH in two or more quadrants. Two test teeth were selected per patient (70 teeth in total) and randomly assigned to PJD or TMD treatment. The efficacy was evaluated using the improvement rate for air and scratch pain according to the scores obtained via visual analog scale 12 weeks after treatment. The safety assessment was performed focusing on gingival index (GI) and spontaneous pain. The t-test was used to analyze the non-inferiority of PJD treatment compared to TMD treatment. RESULTS: The improvement rate of air pain was 69.0% for PJD and 69.7% for TMD. The improvement rate of scratch pain was 80.8% for PJD and 81.7% for TMD. Non-inferiority with a margin of 10% was not observed for both air and scratch pain. No change was observed in GI from baseline and the improvement rate of spontaneous pain for PJD was higher than that for TMD. CONCLUSION: Non-inferiority of PJD to TMD treatment was not observed in this study; however, it was not statistically demonstrated, and the results were thus interpreted as inconclusive. PJD did improve the DH symptoms, as did TMD. PJD's therapeutic effect was most likely attributable to the deposition of a HAP layer on the tooth surface, which would alleviate hypersensitivity for at least 12 weeks without causing severe adverse events. TRIAL REGISTRATION: UMIN-CTR. ID: UMIN000025022. date: 02/12/2016.

Background Cleft lip is the most common congenital anomaly worldwide. Nevertheless, lip somatosensory characteristics of patients with cleft lip after cheiloplasty have not yet been determined. The present study used magnetoencephalography to objectively evaluate the lip sensation in patients with unilateral cleft lip to establish a new objective evaluation method. Methods Participants were 15 patients with unilateral cleft lip after cheiloplasty (UCL group), and 30 healthy young subjects (control group). Five points of the upper and lower lips were stimulated electrically to measure somatosensory evoked magnetic fields (SEFs). The sources of the magnetic fields were modeled as single equivalent current dipoles (ECDs). ECDs located on the central sulcus by superimposition on magnetic resonance images were analyzed. Latency and intensity at 50–75 ms (cP60m) observed in the UCL group were compared with those in the control group. Thresholds of tactile stimuli in both groups were obtained using Semmes–Weinstein monofilaments for subjective sensory evaluation. Results No significant difference was found in the intensity of the cP60m or subjective evaluation between the groups. However, the latency of the cP60m was significantly longer in the upper lip of the UCL group than in the control group. Conclusions SEFs showed a difference in lip sensation between the UCL group and the control group, suggesting that longer latency might be caused by the effects of surgical scarring on the neurotransmission pathway. These results suggest SEFs as useful for the objective evaluation of lip sensations. This study might improve future surgical procedures and lip functions of patients with cleft lip.

This study evaluates the effectiveness and safety of a microscale mist unit (MSM-UNIT) that sprays high-speed fine water droplets to remove dental plaque adhering to the oral mucosa (tongue and palate) and tooth surface. Fifteen patients who had difficulty self-managing sufficient oral care were included in this study. Effectiveness was evaluated for at least five patients' tongues, palate mucosas, and tooth surfaces, and safety evaluation was conducted at all three sites for all patients. Effectiveness was evaluated using the rate of degree of dental plaque removal. Safety was evaluated using a numerical rating scale (NRS) for pain and symptoms of inflammation. An operator who performed treatment and an evaluator who evaluated effectiveness and safety were designated. In addition, an image judgment committee judged effectiveness. Although evaluation of the tongue varied between the evaluators and the image judgment committee, the rates of degree for all plaque removal increased in all regions. In addition, low pain NRS results and minimal symptoms of inflammation were observed and within an acceptable range. The MSM-UNIT can be used effectively and safely for removing oral plaque not only from teeth, but also from the oral mucosa.

The periodontal ligaments are very important sensory organ for our daily life such as perception of food size or hardness, determination of jaw position, and adjustment of masticatory strength. The sensory properties of the periodontal ligament, especially those of the maxillary and mandibular molars, have not yet been fully investigated. Somatosensory evoked magnetic fields (SEFs) can be measured and evaluated for latency and intensity to determine the sensory transmission characteristics of each body parts. However, previous reports on SEFs in the oral region have only reported differences in upper and lower gingival and lip sensations. In this study, the aim was to clarify these sensory characteristics by measuring SEFs during mechanical stimulation of the periodontal ligament in the maxillary and mandibular first molars. Somatosensory evoked magnetic fields were measured in the contralateral hemispheres of 33 healthy volunteers. Mechanical stimulation of the maxillary and mandibular right first molars, and the left wrist was performed with a specific handmade tool. The first peak latency for the mandibular first molars was 41.7 ± 5.70 ms (mean ± SD), significantly shorter than that for the maxillary first molars at 47.7 ± 7.36 ms. The peak intensity for the mandibular first molars was 13.9 ± 6.06 nAm, significantly larger than that for the maxillary first molars at 7.63 ± 3.55 nAm. The locations in the contralateral hemispheres showed no significant difference between the maxillary first molars and mandibular first molars. These locations were more anteroinferior and exterior than that of the wrist, as suggested by the brain homunculus. Neural signals from the mandibular periodontal ligaments pass faster and more intensely to the central nervous system than those from the maxillary periodontal ligaments, and may preferentially participate in adjustment of the occlusal force and the occlusal position.

BACKGROUND: Removal of oral biofilm from the oral mucosa is essential for preventing risk of respiratory and gastrointestinal infection in elderly people. Currently, no device is available which can remove oral biofilm from oral mucosa effectively and safely. Therefore, the effectiveness and safety of the Micro Scale Mist UNIT (MSM-UNIT), a newly developed dental plaque removal device utilizing high speed sprays of fine water droplets, were evaluated for biofilm removal, including the rate and surface roughness for simulated tooth surface and mucous membrane. METHODS: Simulated tooth and oral mucosa coated with an artificial biofilm of Streptococcus mutans were used for evaluation of effectiveness, with uncoated substrates as the controls. The MSM-UNIT and a conventional air ablation device were operated under recommended instructions. The effectiveness was evaluated from the rate of removal of the biofilm, and the safety was evaluated from the damage observed by scanning electron microscope and surface roughness. RESULTS: The biofilm removal rate of the MSM-UNIT was significantly higher than that of AIRFLOW. Little damage was observed in the area treated by the MSM-UNIT. The surface roughness of the MSM-UNIT treated area on simulated tooth surface and oral mucosa showed no significant difference to the control area. In contrast, cracks and powder were observed in the area treated by AIRFLOW. In particular, the surface roughness of the AIRFLOW treated area for Toughsilon was significantly larger than that of the control. CONCLUSIONS: The MSM-UNIT could be used safely and effectively for removing biofilm not only on simulated tooth surfaces but also simulated mucous membrane. The MSM-UNIT has no harmful effect on teeth or oral mucosa, and may be used for comprehensive oral care for patients during nursing care and the perioperative period.

To evaluate the localization of responses to stimulation of the periodontal mechanoreceptors in the primary somatosensory cortex, somatosensory evoked fields (SEFs) were measured for stimulation of the left mandibular canine and first molar using magnetoencephalography in 25 healthy subjects. Tactile stimulation used a handmade stimulus device which recorded the trigger at the moment of touching the teeth.SEFs for the canine and first molar were detected in 20 and 19 subjects, respectively. Both responses were detected in the bilateral hemispheres. The latency for the canine was 62.1 ± 12.9 ms in the ipsilateral hemisphere and 65.9 ± 14.8 ms in the contralateral hemisphere. The latency for the first molar was 47.4 ± 6.6 ms in the ipsilateral hemisphere and 47.8 ± 9.1 ms in the contralateral hemisphere. The latency for the first molar was significantly shorter than that for the canine. The equivalent current dipoles were estimated in the central sulcus and localized anteroinferiorly compared to the locations for the SEFs for the median nerve. No significant differences in three-dimensional coordinates were found between the canine and first molar. These findings demonstrate the precise location of the teeth within the orofacial representation area in the primary somatosensory cortex.

Somatosensory evoked fields (SEFs) to electrical stimulation on the right and left sides of the lower lip were measured using magnetoencephalography and compared in the bilateral hemispheres of 31 healthy normal young and 29 healthy normal elderly subjects to evaluate age-related change in lip somatosensation. The initial peak of the response around 13 ms, designated as N13m, and the second peak of the response, designated as P21m, were investigated. The N13m response, which was detected in 22 of 62 hemispheres in young adults and 37 of 58 hemispheres in elderly adults, showed significantly prolonged latency and increased equivalent current dipole (ECD) moment in the elderly adults. The P21m response, which was detected in 56 of 62 hemispheres in young adults and in 52 of 58 hemispheres in elderly adults, showed longer peak latency in the elderly adults. No significant difference was found in the ECD moment for P21m, which suggests that aging affected the SEFs of the lip somatosensation, but the effects of aging on N13m and P21m differed. Prolonged latency and increased ECD moment of N13m might result from decreased peripheral conduction and increased cortical excitation system associated with aging. Therefore, the initial response component might be an objective parameter for investigating change in lip function with age.