Purpose: Previous studies have reported that bone morphogenetic proteins (BMPs) induced ectopic bone formation when implanted with a carrier material in rats. Thermoreversible gelation polymer (TGP) is characterized by its temperature-dependent dynamic viscoelastic properties. The purpose of this study was to investigate ectopic bone formation upon implantation of recombinant human BMP-2 (rhBMP-2) using TGP as carrier in a rat subcutaneous assay model.
 Methods: Forty subcutaneous pockets were created on the backs of ten rats. The pockets were implanted with rhBMP-2/TGP (N=20) or TGP alone (N=20). The rats were sacrificed at 4 or 8 weeks for histological evaluation.
 Results: In the rhBMP-2/TGP group at 4 and 8 weeks after implantation, ectopic bone formation was found on the surface of the implanted carrier. In the TGP alone group at 4 and 8 weeks, ectopic bone formation was not observed and connective tissue was found on the surface of the implanted carrier. In each case, TGP became hydrogel under 22°C and could be easily removed from the implanted samples.
 Conclusions: The findings of this study suggest that TGP could maintain its thermoresponsive behavior even after it was implanted in vivo. Furthermore, rhBMP-2 in combination with TGP could induce ectopic bone formation around the implanted samples and the ectopic bone could be maintained until 8 weeks after being implanted.

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 Purpose: Bioactive glasses (BAG) raise the activity of osteoblasts in vitro, but it remains unclear whether they enhance the bone formation activity or not in defects of rat parietal bones which have poor bone marrow. Strontium (Sr) enhances the differentiation of preosteoblast to osteoblast and activates it, and also inhibits the differentiation of osteoclast and its activity, thus promoting bone formation. Therefore we created BAGs which contain Sr to enhance the osteogenic property of BAGs and tested their biocompatibility, bioactivity and promotion of bone formation in vivo.
 Materials and Methods: BAG (Sr0) containing 53 SiO₂-20 CaO-23 Na₂O-4 P₂O₅ (wt%) and BAG (Sr20) containing 53 SiO₂-16 CaO-4 SrO-23 Na₂O-4 P₂O₅ (wt%) were prepared using the melt-quench method. Some discs (1 mm thickness, 10 mm diameter) and powders (particle size 250-300 μm) were made. Discs of Sr0, Sr20 and hydroxyapatite were implanted subcutaneously in rats. One month after the operation, the animals were sacrificed and histological observations were performed. Calvarial defects of 8 mm diameter were made surgically in the rats. Powder of Sr0 or Sr20 was implanted into the defects. The rats were divided into three groups: Control: blood clot only, Sr0: defects were filled with Sr0 powder; Sr20: defects were filled with Sr20 powder. At 1, 3 and 6 months after the operation, rats were sacrificed and analyzed by optical microscopy. Formation of new bone and solubility of BAGs were evaluated histomorphometrically.
 Results: The histopathological reactions of Sr0 and Sr20 showed good biocompatibility similar to that of hydroxyapatite. No new bone formation was noted at the center of the calvarial defects of the Control group. At 6 months, Sr0 particles were surrounded by fibrous tissue, and new bone formation was not observed around the particles. Sr20 particles had dissolved markedly, and their cross-sectional area had decreased significantly in comparison to Sr0. At 6 months, new bone formation in the bone defects had increased in comparison to Sr0. It is suggested that Sr ions released from Sr20 promote new bone formation.
 Conclusion: The present study suggested that Sr-substituted BAG should have good biocompatibility and enhance osteogenic property.

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 Purpose: The purpose of this study was to determine the shaping ability of the reciprocating nickel-titanium (Ni-Ti) single-file system (Reciproc: VDW, Germany; WaveOne: Dentsply Maillefer, Switzerland) and rotary multiple system (ProTaper: Dentsply Maillefer) by measuring canal transportation.
 Methods: One hundred and twenty-six J-shaped canals in resin blocks were used in this experiment. The J-shaped canals had three different apical curvatures (10 (n=42), 20 (n=42), 30 (n=42) degrees) and were randomly classified into 6 groups: Reciproc R25, WaveOne Primary, ProTaper SX-S1-S2-F1-F2, Reciproc R40, WaveOne Large, and ProTaper SX-S1-S2-F1-F2-F3-F4. Each group consisted of a model of 10 (n=7), 20 (n=7), and 30 (n=7) degrees. Canal transportation was assessed by comparing pre-instrumentation and post-instrumentation images under an Olympus SZX16 with digital camera DP71, and the superimposed images were analyzed by WinRoof.
 Results: After adjusting for the level and canal wall side, the mean transportation was not significantly different between Reciproc R25, WaveOne Primary, and ProTaper SX-S1-S2-F1-F2 in the final preparation size of ISO#25. A significantly lower deviation was found with Reciproc R40 and WaveOne Large for 10 degrees curvature, by ProTaper SX-S1-S2-F1-F2-F3-F4 for 20 degrees, and by Reciproc R40 for 30 degrees in the final preparation size of ISO#40.
 Conclusions: These findings suggest that the reciprocating Ni-Ti single-file Reciproc and WaveOne are suitable systems for preparing curved canals, the same as the rotary multiple system ProTaper.

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 Purpose: Resin composites are widely used for the direct restoration of both anterior and posterior teeth because of the simple bonding procedure, esthetic demands by patients, and improved physical and mechanical properties of these materials. A smooth surface finish is clinically important, as it determines the esthetics and longevity of the composite restoration. The purpose of this study was to evaluate the surface roughness and surface glossiness of four commercial resin composites after polishing with four commercial one-step polishing systems.
 Methods: A total of 200 specimens (11 mm in diameter, 3 mm thick) were prepared in polyethylene molds using four resin composites: Clearfil Majesty ES-2 (CME; Kuraray Noritake Dental), Filtek Supreme Ultra (FSU; 3M Health Care), Premise (PRM; Kerr) and EsteliteΣ Quick (ESQ; Tokuyama Dental). Control specimens received no polishing treatment (NP group), and the remaining specimens were randomly polished using the CR Polisher PS (CP; Shofu), Opti One Step Polisher (OS; Kerr), PoGo (PG; Dentsply Sankin) or I-Pol (IP; Heraeus Kulzer Japan) system for 30 seconds after being wet-ground with 600-grid silicon carbide paper (#600 group). The average surface roughness (Ra) of each polished specimen was determined with a profilometer (Surfcom590A, Tokyo Seimitsu). The surface glossiness (GS60°) was also determined with a gloss meter (GM-268Plus, Konica Minolta). The data were analyzed using one-way ANOVA followed by Tukey's multiple comparison test. Pearson's correlation coefficient (α=0.05) was calculated to analyze the correlation between surface roughness and surface gloss.
 Results: In all specimens, the roughest surface was observed for the NP group of CME. On the other hand, the smoothest surface was obtained for the IP group of PRM. The highest glossiness value for all specimens was the OS group of FSU. Among all the one-step polishing systems tested, the OS and IP groups exhibited smoother surface and higher gloss for all resin composites. A moderate negative correlation between surface roughness and gloss was found from Pearson's correlation analysis.
 Conclusion: From these results, it was suggested that the effectiveness of the current one-step polishing systems differed depending on the kind of polished resin composites.

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 Purpose: In order to provide safe dental treatment, its systemic influence should be well understood. Accordingly, we developed a novel system for evaluating autonomic nervous activity during dental treatment. This study examined the variability of autonomic nervous activity during local anesthesia and ultrasonic scaling in healthy young volunteers.
 Methods: Blood pressure, heart rate and autonomic nervous activity were measured using the novel system in 10 subjects aged in their 20 s as follows: in both the sitting (2 min) and supine positions (2 min) before treatment; under local anesthesia (2 min); during ultrasonic scaling (5 min); and in the sitting position after treatment (2 min). R-R intervals obtained from electrocardiogram were divided into high-frequency (HF) and low-frequency (LF) components by power spectrum analysis in order to evaluate autonomic nervous activity. HF components reflect parasympathetic nervous activity while LF/HF reflects sympathetic nervous activity. Data were analyzed using the Steel-Dwass test.
 Results: Blood pressure and heart rate values did not differ significantly between treatments. Parasympathetic nervous activity values tended to increase under local anesthesia and during ultrasonic scaling. Conversely, sympathetic nervous activity values decreased significantly under local anesthesia and ultrasonic scaling compared with that in the sitting position before treatment. Our results suggest that emotional stress may influence autonomic nervous activity more than noxious stimuli during local anesthesia and ultrasonic scaling in healthy young adults.
 Conclusion: Sympathetic nervous activity decreases significantly during local anesthesia and ultrasonic scaling compared with that in the sitting position before treatment in healthy young adults.

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 Purpose: The aim of this study was to compare the ultrastructures of root-end cavity walls prepared with Er:YAG laser and an ultrasonic device, and to evaluate the sealing ability and bactericidal effect.
 Methods: Human premolars were used. After the crown was removed, the root canal was enlarged mechanically up to a size of #90. A 3-mm root-end resection was made perpendicular to the long axis of the root. The root-end cavity 3 mm deep from the resected surface was prepared using Er:YAG laser with a cone-shaped tip, and an ultrasonic device with a retrotip as control. Laser energy was set at 80 mJ, and the repetition rate was 20 pps, with water and air cooling. After preparation, the samples were sectioned longitudinally and examined using a scanning electron microscope. For the dye penetration test, after MTA filling, the samples were immersed in a solution containing fluorescent micro-particles for 24 h, and the dentin/material interface of longitudinally sectioned surfaces was observed with a confocal laser microscope (CLSM). In addition, to assess the antibacterial action of laser irradiation, Enterococcus faecalis was cultivated on cavity dentin for 7 days. The samples were then split longitudinally, stained with LIVE/DEAD staining and examined under CLSM.
 Results: Laser-prepared dentin showed a totally ablated cavity surface without smear layer, with open dentinal tubules. Ultrasonic preparation revealed a cavity wall containing superficial debris with occluded dentinal tubules. Leakage tests showed no leakage at the interface between dentin and MTA for both the laser and ultrasonic groups. LIVE/DEAD staining revealed deep penetration of viable bacteria into the cavity wall. After 20 s of laser irradiation, the superficial layer of the cavity wall (ca. 100 μm into dentinal tubules) showed dead bacteria.
 Conclusions: These results suggest that finishing preparation of the root-end cavity with Er:YAG laser irradiation might be feasible for creating excellent root-end cavity walls.

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 Purpose: Recently, some patients prescribed bisphosphonate have suffered from osteonecrosis of the jaw even if they did not receive dental surgical treatment. The aim of this study was to survey osteonecrosis of the jaw found in patients prescribed bisphosphonate at Toranomon Hospital.
 Methods: This survey was started on July 1, 2009. When the dentists found osteonecrosis of the jaw in patients prescribed bisphosphonate, they recorded the following items: 1) name/age/gender of the patient, 2) name of the disease (osteoporosis/malignant tumor), 3) name of the bisphosphonate, 4) term of the prescription, 5) relation to dental surgical treatment, 6) date when osteonecrosis was found, 7) location where osteonecrosis was found, 8) relation to denture, and 9) termination.
 Results: A total of 13 cases of osteonecrosis were found in 12 patients by the end of June 2014. Osteonecrosis appeared after extraction in 4 patients, and appeared without dental surgical treatment in the other 8 patients. Of these 8 patients, osteonecrosis appeared in the denture-bearing area in 3 patients.
 The terminations were as follows: 1 patient spontaneously recovered, 2 patients were cured by treatment by the dentists, the Department of Plastic Surgery, Toranomon Hospital was asked to treat 1 patient, another hospital was asked to treat 1 patient, 1 patient died of lung cancer, and continuous observation was required for 7 patients.
 Conclusion: This survey suggested that there is a risk of osteonecrosis of the jaw in patients prescribed bisphosphonate even if they do not receive dental surgical treatment.

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 Purpose: Matrix trioxide aggregate (MTA) has been used for direct pulp-capping as well as perforation repair due to its potent ability to induce hard tissue regeneration. Pulp exposure, usually caused by tooth fracture and carious tooth treatment, involves the physical damage of pulp extracellular matrix. Therefore, when cells invade the damaged space from surrounding tissue, the existence of an adhesive substrate to aid cell proliferation and differentiation of invading cells is the key factor influencing the prognosis of pulp-capping treatment. In this study, we examined the effects of MTA on the adhesion, proliferation and apoptosis of human dental pulp cells (hDPCs) by comparison with composite resin (CR) and glass ionomer cement (GIC).
 Materials and methods: Ninety-six-well plates were coated with MTA, CR, GIC and fibronectin. Cells were suspended in serum-free medium and then seeded onto coated wells. After 1.5-hr incubation at 37°C, the wells were rinsed to remove non-adherent cells. The number of adherent cells was quantified using the Cell Titer Glo Luminescent Cell Viability Assay Kit. For proliferation assay, these cells were seeded onto MTA, CR and GIC and attached cells were quantified. After 1.5-hr incubation, serum-free medium was replaced with 10% serum medium and cells were cultured onto these substrates for 72 hrs. The ability to induce apoptosis was evaluated by caspase 3/7 activity.
 Result: MTA facilitated the adhesion of hDPCs, while CR and GIC did not. However, the adhesive effect of MTA was much weaker than that of fibronectin. hDPCs could attach onto MTA but not CR or GIC, even 72 hrs after seeding, although the number of attached cells gradually decreased during the culture period. These observations suggest that MTA could be used as a substrate for the adhesion, but not a scaffold for the proliferation, of hDPCs. A drastic increase of caspase 3/7 activity was observed when hDPCs were cultured onto CR and GIC. In contrast, MTA did not induce it.
 Conclusions: Compared with CR and GIC, MTA is a good substrate for hDPC adhesion. These differential adhesive effects may be explained by the differential abilities for inducing pro-apoptotic signals in hDPCs. However, the effect of MTA as a cell adhesion substrate was much weaker than that of fibronectin. More importantly, MTA was unable to induce the proliferation of hDPCs on it. Thus, the co-addition of MTA with other adhesive and migratory proteins such as fibronectin may induce better wound healing and pulp tissue regeneration in vivo.

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 Purpose: The purpose of this study was to examine the effect of warm air-drying on the surface free energy and enamel bond strength of a HEMA-free single-step self-etch adhesive.
 Methods: As the HEMA-free self-etch adhesive system, BeautiBond Multi (Shofu) was employed. Bovine mandibular incisors were mounted in self-curing resin, and wet-ground with #600-grid SiC paper to expose the labial enamel. Adhesive was applied according to the manufacturer's instruction, followed by drying in a stream of warm air for 5 s at 37°C. Normal air-drying at 23°C served as a control. After light irradiation of the adhesive, the surface free energy was determined by measuring the contact angle of three test liquids placed on the cured adhesive. For the determination of enamel bond strength, the adhesive-applied surfaces were dried in a stream of warm air for 5, 10, and 15 s at 37°C, and normal air-drying at 23°C served as a control. Resin composites were condensed into a mold (ɸ4×2 mm) and polymerized. Ten samples per test group were stored in distilled water at 37°C for 24 h, and then shear-tested at a crosshead speed of 1.0 mm/min.
 Results: For all surfaces, the value of the estimated surface-energy component γ_S^LW was relatively constant within the range of 41.7-42.7 mN・m^－1. The enamel bond strengths varied according to the air-drying time, and ranged from 17.4-18.2 MPa. Maximum bond strengths were achieved at air-drying times of 5 s. No significant differences in bond strength were observed with different air-drying times.
 Conclusion: These data suggested that warm air-drying was not effective for increasing the enamel bond strength of the HEMA-free self-etch adhesive, although the Lewis base component decreased with warm air-drying.

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 Purpose: The aim of this study was to evaluate the hardening depth and sealing ability of light-curing MTA-like resin, TheraCal LC, when used as a root end filling material.
 Methods: Human single-rooted mandibular premolars with straight single canals were used. Sample teeth were decoronated and the root canals were enlarged mechanically up to a size of #90, followed by a 3-mm root-end resection perpendicular to the long axis of the root. TheraCal LC was filled in the root-end cavity and light-cured for 20 s. Hardening depth was measured under a microscope. For evaluating sealing ability, the root-end cavity was filled with TheraCal LC or MTA. Specimens were then immersed in an aqueous solution of fluorescent dye for 24 h, longitudinally sectioned, and observed using a confocal laser scanning microscope.
 Results: After 20-s light irradiation, TheraCal LC set to a depth of approximately 7.5 mm. CLSM analysis revealed no dye penetration at the interface between the material and dentin in both TheraCal LC and MTA samples.
 Conclusions: These results suggest that the light-curing MTA-like resin, TheraCal LC, might be feasible as a root-end filling material.

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 Purpose: Tooth bleaching is a common esthetic dental treatment. We evaluated the efficacy of fluoride containing home bleaching agents as caries prevention products in preventing enamel and dentin demineralization.
 Methods: Enamel (n=6) and dentin (n=6) specimens from bovine incisors, with 2×3 mm experimental surfaces made by acid resistant varnish, were divided into four treatment groups: 1. CONT (no treatment), 2. HSU (Shofu HiLite Shade up: 10% carbamide peroxide), 3. OER (Ultradent Opalescence Regular: 10% carbamide peroxide, 2.45 ppmF), 4. OPF (Ultradent Opalescence PF: 10% carbamide peroxide 1,220 ppmF, potassium nitrate). Over four days, a bleaching agent was applied and specimens stored under 100% humidity (37°C, 2 h) then rinsed with tap water (30 s) and a toothbrush followed with deionized water (30 s). Specimens were then immersed in demineralization solution (1.5 mmol/l CaCl₂, 0.9 mmol/l KH₂PO₄, 50 mmol/l acetic acid, 0.1 ppmF, pH 4.6 for enamel and 0.2 ppmF, pH 5.0 for dentin) at 37°C for 22 h and the cycle was repeated for 4 days. Finally, 150 μm-thick enamel sections and 300 μm-thick dentin sections were cut perpendicularly to the experimental surface from each specimen, and mineral profile, lesion depth (Ld) and integrated mineral loss (IML) were determined from radiographic images obtained by transversal microradiography. Elemental analysis (Ca and F) of the enamel lesions were performed with EPMA.
 Results: In enamel, CONT showed severely demineralized subsurface lesions, and HSU revealed subsurface demineralization. OER showed subsurface lesions with four distinct mineral peaks. IML of HSU and OER were significantly less than that of CONT (ANOVA, Tukey's, p<0.05). OPF showed slightly demineralized mineral profiles and IML was significantly less than for other treatments. In dentin, CONT, HSU, and OER showed similar mineral profiles. Also, four mineral peaks were observed in OER; however, they were not as distinct in the lesions of enamel specimens. In contrast, the profile of OPF differed to those of these three groups, with a mineral peak of about 50% of mineral volume. IML of OPF was significantly less than that of other treatment groups. No significant difference was found in Ld among enamel and dentin lesions between CONT and OPF. EPMA revealed Ca peaks were similar in all mineral profiles.
 Conclusion: Fluoride containing home bleaching agents can prevent enamel and dentin demineralization and may act as caries prevention products.

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 Purpose: We examined the effect of a fluoride-releasing coating material containing surface reaction-type prereacted glass-ionomer (S-PRG) filler on enamel demineralization using optical coherence tomography (OCT).
 Methods: Bovine incisors were cleaned and stored in physiological saline. The teeth were sliced, and enamel specimens were shaped into a rectangle (4×4×2 mm). Specimens (n=6) were treated with undersaturated 0.1 mol/l lactic acid buffer solution (pH 4.75) for 10 min, then placed in artificial saliva (pH 7.0; De Group). This treatment was repeated twice daily for 4 weeks, with specimens maintained in artificial saliva at 37°C between treatments. In the second group, a thin film of coating material was applied before demineralization (PRG Group). A third group (Control Group) was maintained in artificial saliva for 4 weeks. Using OCT at selected locations on the enamel surface, peak intensity (dB) and (μm) at 1/e² were measured, and integrated values were calculated. All data were subjected to one-way repeated-measures analysis of variance and the Tukey-Kramer test with a significance level of 0.05.
 Results: The changes in integrated values differed between groups, there was a slight but significant increase in that of the Control Group (1,855-2,425), and a slight but significant decrease in that of the De Group (1,521-1,990). In the PRG Group, the integrated values doubled 7 days after the start of the experiment, followed by a further slight increase (1,560-3,666).
 Conclusion: Fluoride-releasing coating material containing S-PRG fillers prevents enamel demineralization detected by OCT.

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 Purpose: Auto-transplantation of teeth is a viable treatment option for tooth loss because the transplanted tooth resembles a natural tooth histologically. Several studies have reported the advantages of this procedure. However, autotransplantation is often complicated by the size and shape of the donor tooth, thus necessitating careful consideration before implementation. Generally, donor teeth are single-rooted and almost straight, which makes transplantation and root canal treatment easier. However, in this report, we present the favorable results obtained after transplantation of a maxillary third molar with curved and hypertrophied roots in place of a maxillary second molar.
 Case report: A 37-year-old man presented at the Osaka University Dental Hospital with gingival swelling around the left maxillary molars. At presentation, both buccal and palatal gingivae of the left maxillary second molar were swollen and had a fistula. Removal of the full cast crown resulted in a fracture of the pulpal floor, necessitating tooth extraction. The patient opted for autogenous transplantation of the right maxillary third molar (donor tooth) into the socket of the left maxillary second molar. We chose to proceed with the transplantation even though cone-beam computed tomography (CBCT) revealed that the donor tooth had hypertrophic curved roots. Following extraction of both teeth, endodontic treatment was performed extraorally on the donor tooth by using Ni-Ti rotary file systems. The resin-wire splint used for fixation was removed 1 month postoperatively, the tooth was built up with core materials, and a temporary crown was placed. Successful periodontal reattachment of the donor tooth was seen and prosthetic treatment was performed 6 months postoperatively.
 Discussion: Hypercementosis and dilaceration of the roots make extraction of teeth difficult and increase the risk of periodontal ligament injury and rejection of the transplant by the recipient site, contributing to the low success rate of tooth transplantation. The shape of dilacerated teeth especially complicates root canal treatment. In general, the exposure time of the donor tooth to the extra-oral environment is correlated with the success rate; the prognosis is usually better when the exposure time is short. However, we opted to perform extraoral treatment taking into consideration the difficulty of root canal treatment in this case.
 Conclusion: A careful examination of the recipient site with CBCT is recommended and the operative procedure should be chosen depending on the case, even if the donor teeth are curved and hypertrophied, so as to increase the success rate of autotransplantation.

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