Diabetes is a disease that develops due to an abnormal metabolism and is characterized by various complications, such as retinopathy, kidney disease, and neurological impairment, due to pathologically high concentrations of glucose in the blood. There have been many reports so far on the oral changes due to diabetes, such as the onset or exacerbation of dry mouth and periodontal disease caused by a decrease in the volume of saliva secretion. When treating patients with diabetes, it is believed that delayed wound healing occurs in conjunction with a weakening of the patient's resistance to the invasion associated with the treatment due to microvascular disease, acidosis, and abnormal glucose and/or protein metabolism. Therefore, the aim of the present study was to histologically and biochemically examine the effects of diabetes on peripheral vasculature in gingival tissue by determining immunohistochemically the distribution of substance P receptors (NK1R) in rat palatal gingiva and vasoactive intestinal peptide (VIP) receptor 1 (VIPR1), as well as the amount of protein produced in the gingiva. We found that the staining of NK1R and VIPR1 in the gingiva of type 2 diabetes rats was strong around the capillaries. We also observed both receptors in localized areas in connective tissue that was confirmed to have subepithelial inflammatory cells. Finally, VIPR1 was decreased significantly in diabetes.

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We studied the possibility of tissue regeneration using Human Umbilical Cord PeriVascular cells (HUCPVCs). HUCPVCs were harvested from human umbilical cords and were cultured with α-MEM in the presence of 15% FBS. In this study, we examined the growth profiles and the expression of cell surface markers (CD44, STRO-1 and CD34) in vitro. Furthermore, to clarify the osteogenic potential, we investigate the gene expression of the osteoblast phenotype markers osteocalcin (OC), bone sialoprotein (BSP) and Type I collagen (COL I) using reverse transcription-polymerase chain reaction. HUCPVCs were cultured with 50μg/ml ascorbic acid (AA), 10mmol/l β-glycerophosphate (β-GP), 10^-8mol/l dexamethazone (Dex). All three strains stopped proliferation by mean of population doubling (PD) of 12-15. Flow cytometry revealed the prospective evaluation that most of the cells were CD44 positive, CD34 negative, whereas most cells were STRO-1 negative. Following AA, β-GP and Dex treatment, HUCPVCs failed to fuse and transdifferantiated along an osteogenic path-way expressing OC, BSP and COL I. These results show that HUCPVCs pluripotent stem cells are capable of differentiation along osteogenic lineages. HUCPVCs may have possibilities for the development of new tissue regenerative medicine. This study was approved by Tsurumi University Ethics Committee.

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Intentional tooth replantation is considered as a treatment option for preserving the natural dentition. The indications for performing intentional tooth replantation include refractory apical periodontitis, avulsion and teeth with procedural accidents such as root perforation. We followed up changes in symptoms for three patients based on information obtained by 3DX® Multi-Image micro Computed Tomography (3DX), who were diagnosed with chronic apical periodontitis and received intentional tooth replantation. We removed the affected tooth, resected the root apex, and sealed the resected root end surface and perforation sites with 4-META/MMA-TBB resin. The three patients, who complained of occlusal pain, percussion pain and apical discomfort before the treatment, were clinically asymptomatic with normal occlusal function after the intentional tooth replantation. In addition, the teeth showed no radiographic evidence of root resorption or ankylosis. These findings suggested that intentional replantation may be a useful treatment for teeth in cases where other procedures are likely to fail.

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A micro-focus X-ray CT device can be used to examine the inside of a root canal without damaging the specimen, so it is suitable for evaluating morphological changes in prepared root canals or for assessing the sealing property of teeth treated by root canal obturation. The primary aim of the present study was to evaluate the preparing conditions and sealing property of root canals by performing root canal obturation based on the lateral condensation method after preparing 40 mesiobuccal root canals in maxillary first molars by using an engine-driven RT file for curved canals. Based on the findings obtained by the micro-focus X-ray CT device, the conditions of root canals were judged. Further, the conditions of root canal preparation and obturation were assessed, and the following conclusions were obtained from the calculated gutta-percha obturation ratio. From X-ray findings and cross-sectional images, root canals were classified as follows: in the main mesiobuccal canals, there were 20 abruptly curved canals, 20 gradually curved canals, 14 excessively compressed canals, and 26 moderately compressed canals. Further, based on the combination of these two types of findings, canals were divided into: 7 abruptly curved and excessively compressed canals, 13 abruptly curved and moderately compressed canals, 7 gradually curved and excessively compressed canals, and 13 gradually curved and moderately compressed canals. From cross-sectional images taken by the micro-focus X-ray CT device, the preparing conditions and sealing of root canals were examined, and overall images of root canals were clearly identified from three-dimensional CT images. The gutta-percha obturation ratio was: 96.3% in the moderately compressed canal group, 93.3% in the gradually curved canal group, 89.1% in the abruptly curved canal group, and 81.9% in the excessively compressed root canal group. Furthermore, it was 96.4% in the gradually curved and moderately compressed canal group, 96.1% in the abruptly curved and moderately compressed canal group, 87.7% in the gradually curved and excessive compressed root canal group, and 76.0% in the abruptly curved and excessively compressed canal group. Statistical analysis showed that the gutta-percha obturation ratio was significantly influenced by the degree of root curvature and the degree of canal compression, and that the effect of such influence was higher in the degree of compression than in the degree of curvature. These results suggest that the degree of root curvature only slightly influences the condensation of gutta-percha point, while excessive compression of the root canal causes insufficient condensation. Therefore, utmost attention is required at the time of condensation.

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Root canal treatment sometimes fails because of anatomical complexity of the root canal system and/or difficulties of the root canal treatment. To prevent these failures, many disinfectants are used for root canal treatment. However, the anti-microbial efficacies of the disinfectants against the microbes that often remain in the root canal system have not been determined. The aim of this study was to examine the anti-microbial efficacies of disinfectants for root canal treatment against the microbes that remain in the root canals with persistent apical periodontitis using an in vitro model. An experimental periapical lesion model was made from a transparent plastic root canal model. Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis were used as the tested microbes in this study, because many reports suggested that those microbes remained in the periapical lesions even after multiple root canal treatments. An aliquot of 30μl of sterilized Tryptic-Soy (TS) agar, an aliquot of 30μl of sheep blood agar containing approximately 10⁶ CFU of each bacterial cell, and an aliquot of 70μl of TS agar were layered one over another in the hemi-spherical cavity of the sterilized model. Each experiment was conducted using a separate model. For five different root canal treatments, Formocresol (FC); Phenol with camphor (CC); Calcium hydroxide paste (Ca (OH)₂); Dilute iodine tincture (J); and, Minocycline-Ciprofloxacin-Metronidazole mixed paste (3Mix) were tested. After each medicine applications, they were incubated at 37℃ for a fixed period of time (1hr, 1 day, 3 days, 7 days), the agars were taken from the cavity, homogenized, and serially diluted to 10^-3〜^-5. An aliquot of 100μl of each dilution was plated onto the following TS agar, only C. albicans was maintained on the Sabouraud's dextrose agar. The number of microbial cells was expressed as log cfu/ml. Each experiment was conducted five times and the mean and standard error was calculated. The results of this study showed that FC eliminated all microbes completely for a period of 7 days. On the other hand, Ca(OH)₂ pastes could not eliminate C. albicans and S. aureus, furthermore CC and antibiotics (3Mix) could not eliminate most of the microbes. This study suggested that FC was the most effective to eliminate microbes such as C. albicans, P. aeruginosa and S. aureus, E. faecalis that often remain in the root canals of teeth with refractory apical periodontitis.

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The purpose of this study was to evaluate the prognosis of periapical surgery using advanced dental technology with a cone beam computed tomography and a dental microscope. Sixty-nine roots from 51 patients who agreed to the advanced dental treatment were treated and followed-up radiographically for 6 months at the Dental Hospital of Tokyo Medical and Dental University. The treatment was done by specialists of conservative dentistry. The prognostic outcomes were categorized into 4 groups: complete, incomplete, uncertain and unsatisfactory healing. Complete and incomplete healings were regarded as success. The success rate and survival rate of the surgically treated teeth at 6 months postoperatively were 92.1% and 97.1%, respectively. Pain (73.9%) and sinus tract (47.8%) before the treatment were significantly decreased to 34.2% and 7.9%, respectively at 6 months postoperatively (p<0.05). The accurate case selection contributed to the subsequent higher success rate. This technology was effective for the improvement of both sinus tract and periapical lesion, but was ineffective for pain.

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The purpose of this study was to evaluate two kinds of commercial tooth-surface coating materials as anti-demineralizing agents. Cementum surfaces of extracted bovine incisors were used in this study. The samples consist of "coating" surfaces and "non-coating" surfaces. "Coating" cementum surfaces were treated with either "Pain-Free Desensitizer®" (Group P) or "G-Coat®" (Group G), while "non-coating" cementum surfaces were not treated at all. Samples were immersed in 0.1mol/l lactic acid solution (pH=4.8) for 36 hours. After immersion, they were observed with a light microscope, and the thicknesses of demineralized or remaining areas were measured. In both groups, 10 samples were evaluated. One-way analysis of variance (ANOVA) and Fisher's PLSD test were used to determine significant differences of the results. And the cementum-material interfaces were observed with a scanning electron microscope (SEM). The results were as follows: 1. Thickness of "non-coating" bovine cementum demonstrated a significant decrease compared with "coating" cementum. In group P, the thickness of "non-coating" cementum decreased 38.8% compared with "coating" cementum. In group G, it decreased 28.4%. There was no statistically significant difference between the groups. 2. SEM observation revealed no gap formations between tooth-surface coating materials and teeth surfaces in both experimental groups. These results suggested that root surface cementum treated with tooth-surface coating materials could have anti-demineralizing properties.

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