To better understand the clinical features of mass lesions of the tongue, we retrospectively evaluated frequency, recurrence rate, and complications in 296 patients who had undergone surgery for such lesions. The diagnoses were fibroma (43.6%), mucous cyst (14.2%), papilloma (11.8%), hemangioma (7.8%), granuloma (6.4%), lipoma (1.4%), schwannoma (1.0%), ectopic tonsil (0.7%), and other (13.2%). Recurrence was noted in two patients (0.7%). Twenty-two patients (7.4%) developed surgical complications, including lingual nerve paralysis (6.4%), glossodynia (0.6%), and postoperative infection (0.3%). Lingual nerve paralysis was observed in the ventral portion (42.1%) of the tongue, apex (36.8%), lateral border (10.5%), and dorsum (10.5%). When all sites were considered together, there was no significant difference in the number of patients presenting with lingual nerve paralysis (P = 0.075). However, there were significant differences in lingual nerve paralysis at the lateral border (P < 0.05), apex (P < 0.05), and dorsum (P < 0.001) but not at the ventral portion (P > 0.05) in the size of the patients with versus without it which suggests that the risk of lingual nerve paralysis is higher at the ventral tongue, regardless of tumor size. These results shed light on the clinical features of mass lesions of the tongue.

Mannan (mannosylated glycoproteins) in the outermost layer of the Candida cell wall may be the first molecules that interact with host dendritic cells (DCs) and activate immune responses that determine disease outcomes. However, little is known about how different mannan structures of common oral Candida species affect DC activation. The effects of heat-inactivated (HI) yeast cells and soluble mannan of Candida albicans, Candida parapsilosis, and Candida dubliniensis on bone marrow-derived DC (BMDC) responses were compared. HI Candida and the mannan exhibited different effects on BMDC activation and functions, which could be due to other carbohydrate compositions in the yeast cell wall. Among Candida mannan, the C. albicans mannan was the weakest stimulus and induced only interferon (IFN)-γ production. This suggests the possibility that C. albicans mannan may skew T helper (Th) responses from protective Th17 toward Th1. In contrast, C. parapsilosis mannan caused strong BMDC activation and high production of several proinflammatory cytokines which possibly promote hyperinflammation. Meanwhile, C. dubliniensis mannan induced moderate BMDC responses, which may correlate with its lower pathogenicity. Therefore, mannan of each Candida species play distinct roles in DC responses and may be involved in the immunopathogenesis and disease severity of oral candidiasis as well as other Candida infection.

It has been reported that Forkhead box transcription factor class O3a (Foxo3a) is expressed in rheumatoid arthritis, a chronic inflammatory condition accompanied by bone resorption, and plays a role in its pathology. However, it has remained unclear whether Foxo3a is involved in the pathogenesis of periapical granulomas. The present study was performed to compare the expression of Foxo3a in periapical granulomas and healthy gingival tissues. Samples were obtained surgically from patients, and subjected to hematoxylin-eosin staining for histopathologic diagnosis. Two-color immunofluorescence staining was also performed using antibodies against Foxo3a and markers for three types of inflammatory cells: neutrophils, T lymphocytes, and B lymphocytes. This revealed that Foxo3a was expressed in all three cell types in periapical granulomas but not in healthy gingival tissues. Foxo3a was expressed in 82.1%, 78.3%, and 77.5% of neutrophils, T lymphocytes, and B lymphocytes, respectively, and statistical analysis using the Kruskal-Wallis test followed by the Steel-Dwass test showed no significant difference of Foxo3a expression among the three cell types. Our results suggest that Foxo3a transcription factors may be involved in the pathogenesis of periapical granulomas.

In this interventional study, a randomized controlled trial was used to evaluate the short-term effects of xylitol-containing chewing gum on the salivary microbiota. In total, 70 healthy adult men recruited from the Japan Ground Self Defense Force participated in the study during a 2-day training at Yamaguchi camp, Yamaguchi Prefecture, Japan. The men were randomly divided into two groups: one group chewed two pieces of xylitol-containing chewing gum 7 times/day for 2 days (n = 34) and the other did not (n = 36). Baseline and follow-up stimulated saliva samples were collected and the salivary microbial composition was assessed using the 16S rRNA gene next-generation sequencing analysis. The total salivary bacterial count was quantified using a quantitative real-time PCR system. No statistically significant difference was found between the two groups regarding any parameter analyzed in the baseline samples; however, the follow-up samples of the test group showed significantly lower total salivary bacterial count than those of the control group. Conversely, no significant difference was observed in the overall composition of the salivary microbiota between the baseline and follow-up samples of the two groups. These results indicate that xylitol-containing chewing gum inhibits the increase in total salivary bacteria over a short time during which the salivary microbial composition is not affected.

This study investigated the stability of mini-screws placed in the median palate. The study included 25 patients (7 males, 18 females; mean age, 23.4 ± 5.6 years; age range, 15.0-34.5 years) who had mini-screws placed during orthodontic treatment at Nihon University School of Dentistry Dental Hospital. Mini-screws (diameter, 2.0 mm; length, 9.0 mm) were placed in the median palatal region; the first screw was inserted mesiodistally at the distal contact of the maxillary first molar, and the second screw was placed 6-9 mm mesial to the first screw. Immediately after placement, the placement sites were carefully examined with cone-beam computed tomography and a Periotest device. Screw stability was not related to perforation of the nasal cavity, patient age, or patient sex. The success rate was significantly higher in patients with screw-suture distances of 1.5-2.7 mm than in those with distances of 0-1.4 mm. Moreover, mini-screws could be stabilized when palatal cortical bone thickness was ≥1.5 mm. The success rate was significantly higher in the group with insertion depths of ≥4.5 mm. These results indicate that primary stability of mini-screws requires sufficient cortical bone thickness, insertion depth, and screw-suture distance.

The present study was designed to compare the bone augmentation ability of absorbable collagen sponge (ACS) with that of hydroxyapatite/collagen composite (HAP/Col) using a rat calvaria defect model. Bone defects were created artificially on the surface of the calvariae of 10-week-old male Fisher rats, and then cylindral plastic caps filled with ACS or HAP/Col were placed on the defects. This area was designated as the region of interest (ROI) and new bone formation was observed at 0, 4, 8, and 12 weeks after surgery using micro-CT. Histological examinations were performed using sections obtained from 12-week-old rats. Prominent new bone formation was observed in the HAP/Col group relative to the ACS group; onset of new bone augmentation was evident from 4 weeks after surgery in the HAP/Col group and from 8 weeks in the ACS group. Histological examination revealed that the entire area of the cap was filled with newly formed bone intermingled with the HAP/Col composite. Bone mineral density in the HAP/Col group was double that in the ACS group. These results indicate that the use of HAP/Col contributes significantly to new bone augmentation.

The need for domiciliary dental care (DDC) for people requiring long-term nursing care is increasing as the super-aged society of Japan grows still older. Dysphagia diagnosis and rehabilitation are becoming more important in DDC; thus, the need for prostheses used for dysphasia rehabilitation is presumed to be increasing. To identify DDC trends in Japan, as well as the need for prostheses and dental technicians for DDC, we sent a self-administered questionnaire to dentists providing DDC and analyzed responses from 138 dentists (valid response rate, 39.8%). The results showed that 37.7% of respondents reported treating ≥50 patients per month. The most frequently performed procedures were removable prosthetic treatment and oral care, followed by dysphagia rehabilitation. Use of palatal augmentation prostheses was experienced by 54.3% of respondents, and most indicated that the prostheses were effective for improvement of oropharyngeal function. The rates of cooperation with primary care doctors and nursing care professionals were 76.8% and 85.5%, respectively. Only 6.5% of respondents reported accompanying dental technicians to DDC. The present analysis of trends in DDC indicates that oral care and dysphagia rehabilitation have become more frequent and that cooperation with healthcare professionals other than dental technicians has increased in recent DDC.

Using a controlled pre/post study design, we investigated the effects of professional mechanical cleaning of the oral cavity with benzethonium chloride, interdental brushes, and hydrogen peroxide on the number of oral bacteria and postoperative complications among esophageal cancer patients in an intensive care unit. Before surgery, 44 patients with esophageal cancer were recruited at Okayama Hospital from January through August 2015. The control group (n = 23) received routine oral hygiene care in the intensive care unit. The intervention group (n = 21) received intensive interdental cleaning with benzethonium chloride solution and tongue cleaning with hydrogen peroxide. The number of oral bacteria on the tongue surface and plaque index were significantly lower in the intervention group than in the control group on postoperative days 1 and 2 (P < 0.05). Additionally, the number of days with elevated fever during a 1-week period was significantly lower in the intervention group than in the control group (P = 0.037). As compared with routine oral hygiene, a new oral hygiene regimen comprising benzethonium chloride, interdental brushes, and hydrogen peroxide significantly reduced the number of oral bacteria and days with elevated fever in patients with esophageal cancer.

To evaluate the occlusion accuracy of a novel impression technique, excessively high occlusion and the occlusal contact area during lateral movements were compared between metal restorations (restorations) and removable partial dentures (RPDs) fabricated using conventional and novel techniques. Both restorations and RPDs were fabricated on the simulation model with the precise displacement of the remaining teeth and soft tissue. For the novel technique, functionally generated path (FGP) recording and impression under occlusal force were simultaneously performed using a custom tray with an FGP table. For the two conventional techniques, definitive casts were mounted on an average value articulator and a semi-adjustable articulator in the typical manner. Prostheses were placed on the simulation models, and excessively high occlusion in the intercuspal position and occlusal contact areas during lateral movements were measured. Statistical analyses were performed using Kruskal-Wallis and Steel-Dwass tests (α = 0.05). For both prostheses, conventional techniques showed significantly higher occlusion in the intercuspal position than the novel technique. Moreover, the new technique demonstrated better guidance contact during lateral movements than conventional techniques. This novel technique can be recommended for the fabrication of highly accurate prostheses with appropriate occlusal contact without corrections at delivery.

Brain and muscle Arnt-like protein-1 (BMAL1) knockout mice exhibit accelerated aging, abnormal glucose metabolism, and impaired adipocyte differentiation, among other phenotypes, which are effects associated with the BMAL1 gene. No study has investigated temporal changes in the deformation of the mandibular condyle and the presence of calcification in areas surrounding the mandibular condyle. In a study of 12 C57/BL strain mice under inhalation anesthesia, we collected images of the mandibular condyle at 6 weeks after birth and then every 5 weeks from 10 to 25 weeks after birth. At 25 weeks, deformation of the mandibular condyle was seen in 8 of 12 joints in BMAL1 knockout mice and in 2 of 12 joints in wild-type mice. At 20 and 25 weeks, deformation in areas surrounding the mandibular condyle, which are known to undergo calcification, was seen in 2 of 12 joints in BMAL1 knockout mice and in 0 of 12 joints in wild-type mice. BMAL1 knockout mice exhibited premature aging of the mandibular condyle, which suggests that circadian rhythms affect mandibular condyle morphology.

In oral lichen planus, extracellular matrix and basal cells are damaged by T-lymphocytes. As a consequence, changes in expression of collagen fibers within the connective tissue and cytoskeletons of the epithelial tissue can be observed. With the goal of examining the characteristic changes undergone by basal cells as a consequence of T-lymphocytes damage in oral lichen planus, we investigated protein expression in the epithelial-connective junction. We selected 20 cases of oral lichen planus and 5 control samples of buccal mucosa. Subsequently, we divided the oral lichen planus cases into thin and thick parts based on the mean values of epithelial thickness from the control samples, and counted the positive rate of collagen IV, keratin 19, desmoglein 1, and Ki-67. Collagen IV immune-reactivity partially disappeared or thickened in oral lichen planus. The keratin 19 positive rate in oral lichen planus cases was significantly lower than in the controls. Desmoglein 1 positive rate of the thick part was significantly higher compared to the thin part of oral lichen planus. Thus, modifications in basal cells with both reduced keratin 19 expression and alterations of desmoglein 1 expression suggest that in oral lichen planus, as a consequence of cell injury or regeneration in the interface area, there is a disappearance of the “true basal cell nature”.

This study investigated differences in periodontal health variables between buccally impacted maxillary canines (BIMC) and palatally impacted maxillary canines (PIMC) after surgical-orthodontic treatment with open technique. Nineteen patients were enrolled: 10 with unilateral BIMC (5 men, 5 women; mean age 18.50 ± 1.96 years) and 9 with unilateral PIMC (4 men, 5 women; mean age 19.44 ± 2.40 years). Probing depth and keratinized tissue were recorded 12 months after surgical-orthodontic treatment, and the differences between the 2 sides were analyzed as primary outcomes. In addition, data for BIMC and PIMC were directly compared. In the BIMC group, probing depths were significantly higher for lateral incisors than for the untreated side (P = 0.044), and keratinized tissue values were significantly lower for canines than for the untreated side (P = 0.006). No significant differences were observed in the PIMC group. In BIMC, surgical-orthodontic treatment with open technique resulted in loss of periodontal keratinized tissue in the treated tooth and periodontal attachment loss in adjacent lateral incisors. However, the periodontal status of PIMC was not affected by surgical-orthodontic treatment with open technique.

Once a tooth develops deep caries and the dental pulp tissue is irreversibly infected, the infected dental pulp tissue should be removed, and filling material should be placed in the root canal. Endodontically treated teeth are prone to root fracture or periapical periodontitis; however, dental pulp tissue has the potential to prevent root fracture or periapical periodontitis. Therefore, dental pulp regeneration after pulpectomy may help prolong tooth life. In this study, a new method of dental pulp regeneration was developed. Vascular endothelial growth factor-adsorbed collagen gel was injected into the root canal of a prepared root canal model, placed into the dorsum of a rat, and cultured for 3 weeks. After retrieving the implant, histological analysis was performed. It was found that rat somatic cells were recruited into the root apex of the transplanted root canal model. These findings suggest a new potential technique for engineering dental pulp tissue.