Purpose: An amniotic membrane (AM) with anti-inflammatory and anti-infective effects is attracting attention for its usefulness and effectiveness as a culture substrate and graft material, and is currently used in a number of surgical procedures. We previously prepared various cell sheets cultured with AM as the substrate, and demonstrated that some sheets may be effectively used in clinical settings for regenerative medicine. In recent studies, cultured cell sheets derived from the periosteum were transplanted in order to regenerate periodontal tissues. In the present study, periosteal-derived cells (PDCs) were cultured on AM to generate novel periosteal cell sheets, and the kinetics of the cell sheets were immunohistochemically investigated in vivo.

 Methods: AM was removed from the placenta during cesarean section, and periosteal tissues on alveolar bones were collected upon the creation of a mucoperiosteal flap during oral surgery. Periosteal tissues were primarily cultured, followed by three to four passages to obtain PDCs. These cells were seeded on AM, and the epithelial cells that developed were scraped off and then cultured for three weeks. The resulting culture sheets were transplanted under the renal capsules of nude mice, and were removed after 4 weeks for H-E staining and immunostaining.

 Results: PDCs showed a layered structure on AM. Immunostaining images revealed the expression of Ki-67 (a cell proliferation marker), vimentin (a mesenchymal cell marker), and osteocalcin (an osteoblast marker). Desmoplakin (a desmosome marker) and ZO-1 (a tight junction marker) were also expressed with cell sheet formation. Vimentin and osteocalcin were expressed even after transplantation, and the properties of the cell sheets were maintained.

 Conclusion: PDCs proliferated on AM, forming single cell sheets, which demonstrates that AM is suitable as a culture substrate. The periosteum contains cells that have the ability to differentiate into osteoblasts and osteocytes. The cell sheets expressed osteoblast proteins, which were maintained even in an in vivo environment. Thus, PDC sheets may be prepared with AM. A long-term transplantation study will be conducted in the future.

 Purpose: The purpose of this study was to determine the influence of professional mechanical tooth cleaning (PMTC) pastes on the surface roughness of enamel and restoratives, and to assess the plaque removal effectiveness.

 Methods: Five different PMTC pastes, Clinpro Cleaning Paste for PMTC (CP), Concool Cleaning Jell (CJ), Merssage Regular (MR), Merssage Fine (MF), and Merssage Plus (MP), were used. The subject materials used were stainless steel as a substitute proxy for enamel, resin composite, and gold-silver-palladium alloy. A flat surface of each specimen was prepared and polished with a sequence of SiC papers to 2,000-grit. The PMTC procedure was conducted using a bristle brush at 2,000 rpm for 15 sec. The surface roughness was measured with a laser scanning microscope and analyzed using the built-in software. For the assessment of plaque removal efficacy, artificial plaque was applied to the sample surface, and then subjected to PMTC in the same manner as described above. Plaque removal rate was determined using commercial computer software.

 Results: The surface roughness of the specimens tended to increase with the use of PMTC paste. Among the PMTC pastes, MR showed a significantly higher surface roughness. The plaque removal rates were dependent on the PMTC pastes employed.

 Conclusion: Surface roughness and plaque removal effectiveness were material-dependent regardless of the kind of restorative.

 Purpose: The prevention of root caries for older people is an important issue. In light of the current acceptance of bleaching for people of a wide range of ages, in this study we investigated the antimicrobial effects and inhibition of dentin demineralization by home bleaching agents having carbamide peroxide (CP) as their main ingredient, on multispecies biofilms which form on dentin.

 Methods: Frozen simulated saliva from a single donor was diluted 50-fold with an unbuffered McBain semidefined medium containing 0.2 ppmF and 0.2% sucrose, and biofilms were grown on bovine dentin discs (diameter: 6 mm, thickness: 1.5 mm) in it. The medium was refreshed twice daily, after 10 and 14 hours. After the biofilm formation for 24 hours, the biofilms were treated with 0.5% CP solution (0.5CP) or 20-fold dilutions of HiLite Shade Up (0.5HS) or deionized water (Cont) for 30 minutes (n=6). The pH value of each medium was measured at 10, 24 (before treatment), 34 and 48 hours after the inoculation. Specimens were recovered immediately after treatment and at 24 hours after treatment. The number of colony forming units (CFU/ml) was measured. Transverse microradiography (TMR) was used to assess mineral content profiles and integrated mineral loss (IML: vol%×μm) at 24 hours after treatment.

 Results: 0.5HS and 0.5CP showed significantly higher pH values at 10 hours after treatment. 0.5HS and 0.5CP showed significantly less CFU/ml than Cont at both immediately after treatment and at 24 hours after treatment. At those points, 0.5CP showed significantly less IML than Cont.

 Conclusion: It is concluded that carbamide peroxide, as a main ingredient of home bleaching agents, has the effects of decreasing CFU and inhibiting demineralization in a dentin polymicrobial biofilm model.

 Purpose: The influence of a sleeve as a fiber post-reinforcing material on the strength of constructs prepared using a fiber post core construction system was compared with those of constructs prepared using other fiber post systems under two conditions: normal size and narrow root canals, employing two-point bending strength and repeated impact tests.

 Methods: Seven types of fiber post with different diameters and shapes and one type of sleeve were tested. The measured bending strength and number of impacts until fracture were subjected to significance analysis using ANOVA and Tukey tests, setting the significance level at 5%.

 Results: An increase in the fiber post diameter increased the two-point bending strength, but it was not associated with the durability evaluated by the repeated impact test. In the repeated impact test, the durability of the fiber post (φ1.1 mm) with sleeve was markedly higher than that of the other constructs.

 Conclusion: Use of the sleeve markedly improved durability, suggesting that it effectively reinforces constructs.

 Purpose: In the super-aging society, bone fractures in patients with osteoporosis are a serious problem. In dentistry, it is impossible to place an implant in an area without bone of sufficient thickness and strength to support the implant. Therefore, research and development on bone regenerative agents is needed. Biomaterials derived from bovine and porcine sources with zoonosis such as bovine spongiform encephalopathy (BSE) or foot-and-mouth disease can be substituted by collagen peptides derived from skin and bone of fish (FCP). The aim of this study was to investigate the efficiency of FCP for bone regenerative agents using an in vivo rat model.

 Methods: Two cylindrical bone cavities were prepared below the external oblique protuberance (near the posteroinferior portion of the mental foramen) on each side of the rat mandible using a round bar after intraperitoneal anesthesia. After the cavities were washed with sterile physiological saline for hemostasis, FCP was compactly filled into one cavity on each side, then the periosteal flap was repositioned and sutured. The other two cavities remained without filling as a control. At 1, 4, 8, and 12 weeks postoperatively, 48 rats were perfused with a fixative under anesthesia. The specimens were dehydrated in increasing concentrations of ethanol, and then embedded in epoxy resin. Sections were stained with toluidine blue for light microscopic observation.

 Results: At 1 week, in the FCP group, cellular components including osteoblasts proliferated in the bone cavity; the proliferation of cellular components was not detected in the control group. At 4 weeks, in the FCP group, newly formed island-like bone tissues were observed at the entrance of the cavity. Although the cellular components proliferated within the bone cavity, newly formed island-like bone tissues were not observed, and part of the cavity entrance had been already sealed at postoperative 4 weeks by bone-like tissue. In the FCP group, bone regeneration at the periphery of the bone cavity together with the entrance of the cavity progressed at 8 weeks. The cavity entrance was completely closed with osseous tissue at 12 weeks. On the other hand, in the control group, the sealing of the cavity entrance with newly formed bone tissue was incomplete even at 12 weeks.

 Conclusion: The present findings suggest that FCP may be an excellent candidate for clinical application as a bone regenerative agent.

 Purpose: This cross-sectional study aimed to investigate the association between dental conditions, clinical markers of periodontal disease and ischemic stroke or coronary heart disease and to assess the potential influence of occlusal condition or inflammatory response on the observed associations.

 Methods: Ninety-three subjects, including a series of 8 cases with ischemic stroke and 16 with coronary heart disease, were recruited in the study at the Health Sciences University of Hokkaido Hospital. The results of clinical dental examination (number of remaining teeth, number of teeth with probing pocket depth ≥4 mm and 6 mm, percentage and number of teeth with bleeding on probing sites, mean probing pocket depth, periodontal inflamed surface area, Eichner’s classification) and medical or biological parameters (sex, age, alcohol intake, smoking, diabetes mellitus, hypertension, dyslipidemia, pharmacotherapy of these three diseases, hs-CRP, fasting blood glucose, BMI, blood pressure, total cholesterol, HDL, non HDL, LDL, VLDL, triglycerides) were collected. Pearson’s chi-square test, Fisher’s exact test or Mann-Whitney test and multivariable analyses were performed to identify factors associated with ischemic stroke and coronary heart disease.

 Results: The prevalence of Eichner’s C was significantly higher, and that of Eichner’s A, total cholesterol and HDL were significantly lower in ischemic stroke patients. In the results of binary logistic regression analysis, the odds ratios for ischemic stroke were higher in the group of patients with Eichner’s C (OR=17.381, p=0.013, 95% CI=1.848-163.489) and with lower HDL cholesterol (OR=0.894, p=0.020, 95% CI=0.813-0.982). However, total cholesterol (OR=0.968, p=0.083, 95% CI=0.934-1.004) and hs-CRP (OR=1.604, p=0.090, 95% CI=0.929-2.771) were not statistically significantly different. Every possible predictor that was taken into account was not associated with coronary heart disease.

 Conclusion: This study demonstrates that Eichner’s C is independently associated with ischemic stroke.

 Purpose: Apical periodontitis can originate from pulpitis, root fracture, or dental trauma, and an odontogenic cutaneous sinus tract may secondarily develop after the occurrence of apical periodontitis. This apical periodontitis is associated with the development of skin lesions, which means that the affected teeth are non-vital. Here, we report that a cheek erythematous lesion not accompanied by an odontogenic cutaneous sinus tract-like lesion was improved by pulpectomy.

 Case: The patient had a cheek erythematous lesion which occurred after the extraction of a completely impacted third molar. An odontogenic cutaneous sinus tract-like lesion was confirmed using magnetic resonance imaging (MRI). Pulpectomy and conventional root canal treatment for mandibular left first and second molars improved the cheek erythema.

 Conclusions: MRI is considered to be an excellent tool for diagnosing the path of least resistance, where the purulent byproducts due to infection can travel through the bone and soft tissue. Although this case was not a typical odontogenic cutaneous sinus tract-like lesion, because the causal teeth were vital and there was no fistula, pulpectomy and root canal treatment were effective for healing the cheek erythema.