Early identification of leukoplakic oral squamous cell carcinoma (OSCC) is difficult. The purpose of this study was to determine whether it was possible to detect change from normal epithelium to leukoplakic OSCC using a fluorescence visualization (FV) device in a 4-nitroquinoline 1-oxide (4NQO) -induced rat tongue cancer model. If successful, this would facilitate early detection of OSCC. The rats (3 groups of 5) were administered 50 ppm 4NQO in their drinking water over a period of 10, 15, or 20 weeks. Five non-treated rats were used as a control group. Images of their tongues obtained by FV were analyzed for change in fluorescence intensity (FI) using image analysis software. Immunoreaction for anti-CK13, anti-CK17, and anti-E-cadherin antibodies was also histopathologically evaluated. Receiver operating characteristic (ROC) analysis was used to calculate the cut-off values, sensitivity, specificity, and area under the curve. The most marked change in FI was found between the control and 10-week groups, with an increase observed in its average value and range in the latter. These findings differed from those characteristic of leukoplakia. No significant difference was observed in the positive cell rate for immunoreaction for anti-CK13 or anti-CK17 antibodies between the control and 10-week groups. A significant decrease was observed in the positive pixel ratio of immunoreaction for anti-E-cadherin antibody in the 10-week group in comparison with in the control group (p <0.05). These results showed that disruption of intercellular adhesion could be observed at 10 weeks. In the ROC analysis, the FI cut-off value in the 10-week and control groups was 51.9, sensitivity 95.5%, and specificity 96.9%. This indicated that normal epithelium could be accurately distinguished from low-grade dysplasia with high probability. These results demonstrate that analysis of change in FI as measured by FV could facilitate early detection of leukoplakic OSCC.

Chronic periodontitis is an infectious disease caused by periodontopathic bacteria in subgingival plaque. One major pathogen of this disease, Treponema denticola, has several virulence factors, including a major surface protein (Msp) and the surface protease dentilisin. The cytopathic effects of periodontopathic bacteria on epithelial cells disrupt the integrity of the barrier junction, resulting in the inflammation of periodontal tissue. The aim of this study was to investigate the effect of T. denticola virulence factors dentilisin and Msp on epithelial cells. The effects of T. denticola wild-type, Msp-mutant, and dentilisin-mutant strains on the contact junction in Madin-Darby canine kidney epithelial cells was evaluated based on ohmic values. Cultured oral carcinoma epithelial cells were scratched and exposed to the selected T. denticola strains and cell migration determined. Subsequent degradation of adherence proteins and proteins in the contact junctions was evaluated. Dissociation of cell contact junctions was detected in cells infected with wild-type T. denticola approximately 30 min after infection, but not in those exposed to the mutants. Inhibition of migration was observed in the wild-type and Msp-deficient mutants. The adherent proteins focal adhesion kinase, ZO-1, and paxillin were hydrolyzed by infection with the wild-type and Msp mutants. These results indicate that T. denticola disrupts the function of epithelial cells by hydrolyzing proteins at the intercellular junction and inhibiting healing of epithelial cells via hydrolyzed proteins associated with focal adhesion; Msp was also associated with these effects.

This report describes long-term implant treatment in a patient with chronic periodontitis. The patient was a 59-year-old man who attended our facility requesting a dental implant. An initial examination revealed generalized gingival inflammation and subgingival calculus. Clinical examination revealed 55.3% of sites with a probing depth (PD) of >4 mm and 41.3% of sites with bleeding on probing. Radiographic examination revealed vertical bone resorption in #23, #33, #33, #35, and #47. Initial periodontal therapy consisting of plaque control, scaling and root planing, and tooth extraction was subsequently performed based on a clinical diagnosis of severe chronic periodontitis. Open flap debridement was performed for teeth with a PD >5 mm (#21, #22, #23, 333, #34, #35 and #47). After confirming the stability of the periodontal tissue, 3 implants were first placed in the maxilla (#25, #26, and #27). Final prostheses comprising a screw retaining-type implant superstructure were then placed (#25, #26, and 327). Following reevaluation, the patient was placed on supportive periodontal therapy. At 15 years after the first visit, the periodontal and implant conditions have remained stable. These results indicate that periodontal treatment before implantation and subsequent maintenance yield a clinically favorable and long-lasting outcome.

This report describes a case of chronic periodontitis requiring treatment including smoking cessation care and periodontal surgery in an elderly patient with a long-term smoking habit. The patient, a 79-year-old man, presented with the chief complaint of halitosis. He had a 56-year history of smoking cigarettes. An initial examination revealed that 34.5% of sites had a probing depth (PD) of ≥4 mm, with 24.1% of sites showing bleeding on probing (BOP). Open bite and loss of appropriate anterior and lateral guidance were also found. Radiographic examination revealed extensive horizontal bone resorption in the maxillary and mandibular molars. Based on a clinical diagnosis of severe generalized chronic periodontitis, initial periodontal therapy consisting of plaque control, smoking cessation care, scaling and root planing, and caries treatment of #47 was performed. Prosthetic treatment with a removable partial denture was planned for #26, which was missing. The patient quit smoking at the end of initial periodontal therapy. Subsequently, surgical periodontal therapy including open flap debridement was performed on #16, #17, #18, and #27. Following reevaluation, a full metal crown (#47) and removal partial denture (#26) were placed. The patient was then placed on supportive periodontal therapy (SPT). Periodontal treatment including surgical therapy resulted in an improvement in PD and a reduction in the number of sites with BOP. The patient has not started smoking again since initial treatment. Improvement has been adequately maintained over a 4-year period. The present results suggest that even when a patient has been exposed to a risk factor for a long time, periodontal treatment and control of that risk factor can contribute to stabilization of periodontal conditions. Some problems with occlusion have persisted, however. Additional care is necessary to retain stable periodontal conditions during SPT.

In Japan, domiciliary care fees are only covered by the public health insurance system if the clinic concerned is located within 16 km of the patient’s residence. This nationwide rule does not take local conditions into account and therefore may not be appropriate. The goal of the present study was to assess the current state of domiciliary dental care nationwide in view of this restriction to clarify the current situation and any inherent problems. Six dental institutions providing domiciliary dental care were selected by location (urban or mountainous area) and size. Travel time from clinics to the 16 km points and the longest time required for the journey from clinics were investigated. Two of the dental clinics were located in depopulated areas with few dental institutions. These clinics had to provide domiciliary dental care not only in the 16-km area around the clinic, but also in areas over 16 km away. Travel time to the 16-km points was between 52 and 90 min. On the other hand, the longest time for actual visiting was between 30 and 60 min. In some areas, no domiciliary dental care was available within the 16 km limit. This indicates that the 16-km area is too wide to be covered by one dental institution alone and that it poses a problem in areas with few dental institutions. This suggests that it would be preferable to consider time required to visit rather than geographical distance in forming policy. The 16-km limit often spans multiple residential areas, indicating that greater coordination is needed between the Community-based Integrated Care System and dental offices.