Clinical Effect of Virtual Reality to Relieve Anxiety During Impacted Mandibular Third Molar Extraction Under Local Anesthesia.

PURPOSE: Many patients undergoing dental treatment have experienced pain associated with the treatment and become anxious and/or fearful of treatment. Anxiety and fear have conventionally been managed with the use of inhalation anesthesia or tranquilizers. However, their physical effects must also be considered, and they will not be suitable for all patients. The purpose of the present study was to assess the clinical effect of virtual reality (VR) to relieve anxiety during impacted mandibular third molar extraction under local anesthesia. MATERIALS AND METHODS: We used VR to alleviate anxiety concerning surgical treatment for 51 patients undergoing impacted mandibular third molar extraction under local anesthesia. Fear and anxiety before and after treatment were evaluated by a questionnaire that included a visual analog scale (VAS). The post-treatment questionnaire asked patients to evaluate their satisfaction on a 5-level Likert scale. Heart rate variability (HRV) was also analyzed in the VR group using acceleration plethysmography. RESULTS: Anxiety had decreased among the patients who had used VR (VR group), with a difference of -13.3 ± 28.7 mm in anxiety measured using a VAS before and during treatment. In contrast, it had increased by 4.0 ± 22.3 mm in the 49 patients who had not used VR. Furthermore, the post-treatment questionnaire administered to the VR group revealed that 92% had reported that their anxiety had decreased. Objective evaluation by HRV measurement also showed a sympathetic nerve-predominant state before treatment. However, with VR use during treatment, parasympathetic nervous activity was predominant, with a stable balance between the 2. No patient showed symptoms suggestive of cybersickness. CONCLUSIONS: These results have shown that the use of VR could be valuable during dental treatment, especially extractions and surgical treatment.

Clinical evaluation of steroid ointment for the treatment of mucoceles.

OBJECTIVE: We examined whether steroid ointment (0.1% dexamethasone) is an effective treatment for mucoceles. STUDY DESIGN: Using a retrospective cohort study design, a statistical study was conducted of 91 patients diagnosed with mucoceles at the Department of Dental and Oral Surgery, Saga University Hospital, Saga, Japan, between January 2006 and December 2016. The patients' age and sex; shape, size, and site of the lesion; duration; and treatment response rate were evaluated. RESULTS: The most frequent site of mucoceles was the lower labial mucosa, and several were <10 mm in size. The age of onset was often <20 years, with no sex-based differences. The treatment response rate was 65.8% for steroid ointment and 100% for surgical removal. In the subgroup analysis according to each clinical factor, some subgroups showed statistically nonsignificant differences compared with the surgery group. Among them, the older age and short disease duration subgroups showed small risk differences, suggesting that application of ointment may lead to a response in these subgroups. CONCLUSIONS: Although its response rate was lower than that of surgical removal, topical steroid application is a noninvasive and useful treatment method that can be used for patients in whom surgical treatment is infeasible.

TRPV2 expression in rat oral mucosa.

The oral mucosa is a highly specialised, stratified epithelium that confers protection from infection and physical, chemical and thermal stimuli. The non-keratinised junctional epithelium surrounds each tooth like a collar and is easily attacked by foreign substances from the oral sulcus. We found that TRPV2, a temperature-gated channel, is highly expressed in junctional epithelial cells, but not in oral sulcular epithelial cells or oral epithelial cells. Dual or triple immunolabelling with immunocompetent cell markers also revealed TRPV2 expression in Langerhans cells and in dendritic cells and macrophages. Electron microscopy disclosed TRPV2 immunoreactivity in the unmyelinated and thinly myelinated axons within the connective tissue underlying the epithelium. TRPV2 labelling was also observed in venule endothelial cells. The electron-dense immunoreaction in junctional epithelial cells, macrophages and neural axons occurred on the plasma membrane, on invaginations of the plasma membrane and in vesicular structures. Because TRPV2 has been shown to respond to temperature, hypotonicity and mechanical stimuli, gingival cells expressing TRPV2 may act as sensor cells, detecting changes in the physical and chemical environment, and may play a role in subsequent defence mechanisms.

Distribution of substance P and neurokinin-1 receptors in the peri-implant epithelium around titanium dental implants in rats.

We examined the distribution of substance P and neurokinin-1 (NK1) receptors and substance-P-containing nerve fibers in the peri-implant mucosa around titanium dental implants in rats. Immunohistochemistry and immunocytochemistry revealed that substance-P-immunoreactive nerve fibers abundantly innervated the peri-implant epithelium (PIE) compared with other epithelia of the peri-implant mucosa. NK1 receptor mRNA and protein expression in the peri-implant mucosa were confirmed by reverse transcription with the polymerase chain reaction and immunoblotting. Immunoelectron microscopy revealed that NK1 receptor immunoreactivity was preferentially localized in peri-implant epithelial cells. NK1-receptor-positive products were found on the plasma membrane and in vesicles and granules in PIE cells. Neutrophils and intraepithelial nerve axons in the PIE were positive for the NK1 receptor. NK1 receptor immunoreactivity was also detected in endothelial cells, fibroblasts, and nerve fibers in the connective tissue beneath the PIE. These findings suggest that peri-implant tissue receives sensory information through regenerated nerves expressing substance P and the NK1 receptor. In the peri-implant mucosa, the substance P/NK1 receptor system may play a role in pain transmission, the endocytosis of neutrophils, the extravasation of crevicular fluid, and the migration of macrophages and neutrophils in response to neurogenic inflammation, as in healthy gingiva.

Cystatin C stimulates the differentiation of mouse osteoblastic cells and bone formation.

Cystatin C (CysC) is a natural cysteine proteinase inhibitor that suppresses the differentiation and bone-resorptive function of osteoclasts. By contrast, the effect of CysC on the differentiation and bone-formative function of osteoblasts has not been elucidated thoroughly. We examined the effects of CysC on mouse osteoblastic cells using in vitro cultures from bone marrow and calvaria and ex vivo calvarial cultures. CysC-stimulated cells showed increased alkaline phosphatase (ALP) activity, mineralization of the new bone matrix, and calvarial bone formation. The cells treated with CysC immunodepleted by anti-CysC antibody (iCysC) and a chemical papain-like cysteine proteinase inhibitor, E-64, did not induce mineralization. Elevated mRNA levels of bone morphogenetic protein (BMP)-2, the differentiation marker osteocalcin, and a master osteogenic transcription factor, Runx2, were observed in CysC-treated cells. These results suggest that CysC affects the BMP signaling cascades in osteoblastic cells and then promotes osteoblast differentiation, mineralization, and bone formation.