Purpose: Listerine mouthrinse has been reported to show a rapid membrane-damaging effect on biofilm bacteria. One drawback of Listerine, however, is that it may be irritative to oral mucosa due to the ethanol contained as a solvent. The aim of this study was to evaluate the penetration kinetics and antimicrobial effects of a new alcohol-free essential oil mouthwash (Listerine Zero), which has been developed to lower the irritative action of Listerine. Methods: Listerine Zero (Z), Listerine Fleshmint (F) and a chlorhexidine gluconate-containing mouthrinse (Peridex; P) were investigated as test mouthrinses, and a buffer was used as a negative control. Streptococcus mutans biofilms were grown on glass-based dishes for 24 h under anaerobic conditions. Penetration kinetics of the mouthrinses were analyzed with time-lapse confocal laser scanning microscopy where the fluorescence loss of calcein-AM-stained biofilms was monitored after exposure to mouthrinse. Antimicrobial effects of the mouthrinses were also compared using live/dead staining and plate counting. Results: The maximum biofilm thickness developed in this study was approximately 32 μm. The time required to reach 50 % of the initial fluorescence intensity (T50) and biofilm thickness exhibited a high correlation coefficient. P showed significantly smaller penetration velocity compared with the others, whereas there was no significant difference between Z and F. The live/dead staining analysis after 30 s exposure revealed that propidium iodide (a dead cell marker)-positive percentage was 99.8±0.1 % for Z and F and 41.4±5.9 % for P When viable cell counts after 30 s of mouthrinse exposure were determined by plate counting, all of the mouthrinses caused a significant reduction compared with the control. F and Z caused significantly smaller counts than P whereas there was no significant difference between Z and F Conclusion: Listerine Zero was as effective as Listerine Fleshmint in penetration property and antimicrobial effect against S. mutans biofilms of less than 32 μm thick. Both of these mouthrinses also showed significantly superior penetration property and antimicrobial effect than the chlorhexidine gluconate-containing mouthrinse.

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Purpose: The removal of cast posts is difficult and involves risks (root fracture), and it is necessary to remove cast posts "speedily", "surely" and "safely" (3S). Therefore, this study was developed from the past papers, and clinically investigated the methods of removing cast posts which might attain the 3S readily by comparing two kinds of post and core remover (PR, YDM). Methods: The subjects were 39 teeth (out of 35 patients who visited Ouki Dental Clinic) which were cemented metal post and core (cast post), and the group in which cast posts were removed by standard-type PR was defined as Group RC, and the group in which cast posts were removed by improved-type PR was defined as Group RSC. Their cast posts were removed by one of the following methods. The tooth was grooved at two locations, one on the buccal side and the other on the lingual side, on the metal core margin by a carbide bar #1970 for FG, then the two tips of the PR were inserted into these locations and the cast post was slowly removed by the gentle clasping force of the PR. We evaluated the time taken to remove cast posts, the length of the post portion, the existence of a root fracture line by the coloring matter flooding test, probing pocket depth and so on. Results: Almost all cast posts were removed within 5 minutes [Group RC: 18/18, Group RSC: 21/21 (unit : piece)]. The average time taken to remove cast posts was 103±77 (Group RC), 99±69 (Group RSC) (unit : second); the removal time in Group RSC was a little shorter than that in Group RC, and the removal time classified by PR was not significantly different (Mann-Whitney U test, p≧0.05). The average length of the post portions was 5.9±1.8 mm (Group RC) and 5.7±1.6 mm (Group RSC); the post portions of removed cast posts were not significantly different (Mann-Whitney U test, p≧0.05). Using a #1970 narrow carbide bar for FG might decrease tooth matter the least. Furthermore, using the PR for removing cast posts is unlikely to cause root fracture, spontaneous pain, percussion pain, periodontal pocket deepening or tooth mobility after removal. In particular, percussion pain, periodontal pockets (probing pocket depth) and tooth mobility more than one month after removing cast posts were significantly more stable compared with before removal (Wilcoxon signed rank test, p<0.05). Conclusion: These results indicated that cast posts might be removed speedily, surely and safely (3S). In addition, the improved-type PR could remove cast posts a little faster than the standard-type PR.

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Purpose: Several clinical reports on MSC-based disease treatment have been published, evoking great excitement and therapeutic potential for a variety of diseases. There have been, however, no biosafety reports on clinical trials harnessing pulp stem cells. We must follow the principle of clinical trials using human stem cells to manufacture clinical-grade pulp stem cells. Thus, stringent controls in all the phases of cell manipulation using an isolator in a GMP-compliant facility were performed by the standard operating procedure (SOP) to determine the quality and safety of the pulp stem cells. Materials and Methods: Clinical-grade human pulp stem cells were isolated and expanded according to GMP conditions. Pulp stem cells were isolated based on their chemotactic response to a granulocyte-colony stimulating factor (G-CSF) gradient from pulp cells separated by an enzymatic digestion method. The cells were expanded until the 7th, 15th and 20th passage of culture and were frozen by a programming freezer. The safety tests for bacteria, fungus, virus, endotoxin, and mycoplasma were performed in transportation solution after use, the primary cell culture medium and finally frozen cells at the 7th passage. Expression rate of stem cell markers was analyzed by flow cytometry. Human pulp stem cells were injected into testes or subcutaneously in NOD/SCID mice and KSN nude mice for tumorigenicity assay. The metaphases of pulp stem cells were Q-banded and karyotyped at the 20th passage of culture. Results: The pulp stem cells were isolated, expanded until the 7th passage of culture and frozen in the isolator. The viability of the cells was over 80%, and the expression rate of cell surface markers CD29, CD44, CD73, CD90 and CD105 was over 95% and CD31 expression was negative, indicating their sternness. The pulp stem cells demonstrated negative results in all safety examinations including endotoxin (less than 1.0 pg/ml), no tumor formation and no abnormalities/aberrations in karyotype. Conclusion: The quality and safety of human pulp stem cells manufactured in the GMP-compliant facility and a stable manner using the SOP were demonstrated. In the near future, novel treatments of pulpitis will become routine once the first clinical trial is successfully performed to confirm safety and efficacy, paving the way for more advanced stem cell therapies in dentistry and endodontics.

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Purpose: Including mild cases, the incidence of dentin hypersensitivity during or immediately after bleaching is reported to be 55-75 %. One causal factor may be enamel lamellae or microcracks in the enamel. The purpose of this study was to observe the enamel microcrack sealing performance of a newly developed calcium phosphate based desensitizer applied according to the manufacturer's directions, and to investigate the effects of desensitizers on bleaching performance. Methods: The materials used in this experiment were Teethmate desensitizer ("TMD"; Kuraray Noritake Dental) for suppressing hypersensitivity and Shofu Hi-Lite (Shofu) and Shofu Hi-Lite Shade Up (Shofu) for bleaching vital teeth. In-office bleaching was performed using Shofu Hi-Lite on extracted human front teeth with cracks using the standard methods. Then, TMD was rubbed into the teeth for 30 seconds, and the crack sealing performance was observed under a stereomicroscope and scanning electron microscope. In another experiment, TMD was rubbed into only half of the front teeth with cracks to create a TMD coated surface and non-coated surface, and at-home bleaching trays were fabricated such that they covered each surface. Next, at-home bleaching was performed with Shofu Hi-Lite Shade Up for a total of 28 hours. Teeth were then observed with a spectral colorimeter (Spectro Color Meter SE-2000; Nippon Denshoku Industries). CIE L*a*b* values were calculated with a gray background of luminosity 5 and the color differences (ΔE*ab) were compared. The results of ΔE*ab were statistically analyzed using Tukey's multiple comparison method (α=0.05). Results: Observation by scanning electron microscopy revealed that TMD had filled the enamel microcracks. In addition, the color difference ΔE*ab between before and after bleaching the TMD-coated surface on a gray background was 11.59±2.75, while ΔE*ab of the control surface between before and after bleaching was 12.48±1.10. There were no differences in ΔE*ab between the TMD-coated and control surfaces. Conclusions: Calcium phosphate-based desensitizers can seal enamel microcracks and do not affect bleaching performance, indicating that they may be useful before or during bleaching.

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Purpose: Elimination of microorganisms from the root canal is necessary to resolve apical periodontitis. Antibacterial activity is required in the temporary filling to protect against entry of bacteria into the root canal. The present study was designed to investigate the antibacterial activity of temporary filling materials against oral bacteria. Methods: Zinc oxide eugenol cement, hydraulic cement, fluorine-containing hydraulic cement, polymeric filling material and photopolymerized material were used. The antibacterial activity of these materials against Porphyromonas gingivalis ATCC 33277, Fusobacterium nucleatum TDC 100, Parvimonas micra JCM 12970, Streptococcus mutans Ingbritt and Streptococcus sanguinis ATCC 10580 were investigated by the diffusion method. Data were analyzed using the Kruskal-Wallis test at a significance level of 5 %. Results: The antibacterial activity against P gingivalis of zinc oxide eugenol cement was significantly higher than those of hydraulic cement and photopolymerized material. Antibacterial activity against F nucleatum was also observed for zinc oxide eugenol cement, hydraulic cement, and fluorine-containing hydraulic cement. Against P micra, only zinc oxide eugenol cement showed antibacterial activity, and against S. mutans and S. sanguinis, antibacterial activity was observed for zinc oxide eugenol cement and fluorine-containing hydraulic cement. High antibacterial activities were observed for zinc oxide eugenol cement and fluorine-containing hydraulic cement, but none of the photopolymerized material specimens showed activity. Conclusion: Antibacterial activity differed between temporary filling materials, suggesting that the antimicrobial constituents of temporary filling materials influence antibacterial activity.

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Purpose: The purpose of this study was to investigate the efficiency of the newly-developed LED curing light unit, VL-10 (VL, Morita). The VL has two heads, one of which is for single wave (SW, 460 nm) and the other is for double wave (DW, 460 nm+405 nm). The efficiency of VL was evaluated by measuring the tensile bond strength (TBS) of a resin composite in comparison with Pen Cure (P, Morita), which is a commercially available LED curing light unit. Methods: The facial surface of bovine incisor was ground with wet SiC paper up to 600 grit to prepare the dentin surface. The prepared surface was conditioned by Primer of Clearfil Mega Bond (MB, Kuraray Noritake Dental), followed by the application of bonding of MB. The applied bonding was light-irradiated under the following conditions. (1) Control: Using P for 10 seconds (2) VL-SW1s: Using VL-SW high-power mode for 1 second (3) VL-SW2s: Using VL-SW high-power mode for 2 seconds (4) VL-SW3s: Using VL-SW high-power mode for 3 seconds (5) VL-SW10s: Using VL-SW normal-power mode for 10 seconds (6) VL-DW1s: Using VL-DW high-power mode for 1 second (7) VL-DW2s: Using VL-DW high-power mode for 2 seconds (8) VL-DW3s: Using VL-DW high-power mode for 3 seconds (9) VL-DW10s: Using VL-DW normal-power mode for 10 seconds A resin composite (Clearfil AP-X, shade A3, Kuraray Noritake Dental) was filled and cured by XL-3000 (3 M ESPE). TBS was determined after 24-hour storage in water at 37℃ (n=8). The obtained data was analyzed by oneway ANOVA and Tukey's test (α=5%). Results: The measured TBS (mean±SD, MPa) were as follows: Control: 17.9±3.3, VL-SW1s: 11.8±3.8, VL-SW2s: 16.0±3.1, VL-SW3s: 18.2±3.8, VL-SW10s: 20.5±4.7, VL-DW1s: 16.5±4.4, VL-DW2s: 18.4±3.5, VL-DW3s: 19.7±2.0, and VL-DW10s: 20.4±2.9. No significant difference was found for all conditions except VL-SW1s. TBS with VL-SW3s, VL-DW3s and VL-DW2s were equivalent to that of the control. Conclusion: The newly-developed VL with high-power mode was able to shorten the polymerization time of the bonding resin.

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Purpose: There are many reports of gingival swelling caused by endodontic-periodontal disease, but few reports concerning swelling of the lower eyelid in association with endodontic-periodontal disease. We report the efficacy of cone-beam computed tomography (CBCT) in the diagnosis and treatment of endodontic-periodontal disease followed by the expansion of periapical inflammation for the orbit. Case description: The patient was a 52-year-old male manifesting with gingival abscess and swelling of the lower eyelid. We diagnosed that the maxillary left lateral incisor was acute purulent apical periodontitis and endodontic-periodontal lesion on the basis of subjective and objective clinical symptoms and CT imaging. In addition, it was speculated that fenestration in the vicinity of the root apex might have been involved in the expansion of periapical inflammation for the orbit. We therefore performed infected root canal treatment of this tooth using 3D-images of CBCT. After 3 months, the patient was clinically asymptomatic, and a periapical radiolucent area was not observed. Conclusion: The use of CBCT was extremely effective in the diagnosis and treatment of endodontic-periodontal disease showing gingival abscess and extraoral swelling.

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