Purpose: In order to preserve the dental pulp, it is necessary to effectively promote the formation of hard tissue. In recent years, research has been carried out with the aim of developing an adjunct to pulp capping by using Ga-Al-As lasers on human dental pulp cells (hDPCs) to promote the formation of hard tissue. However, their effects on hDPCs have not yet been clarified. The present study investigated the effect of the wavelength of laser irradiation on the acceleration of calcification in hDPCs.

 Methods: This study was approved by the ethics committee of Nihon University School of Dentistry, Matsudo, Japan. hDPCs were harvested from third molars extracted under aseptic conditions from 20-year-old patients undergoing orthodontic treatments. hDPCs were cultured in alpha-minimal-essential medium supplemented with 10% fetal bovine serum for up to 30 days, and irradiated with a Ga-Al-As laser at a wavelength of 660 nm or 810 nm and an output of 300 mW, approximately 10 cm above the culture supernatant. Alkaline phosphatase (ALP) activity and bone morphogenetic protein (BMP)-2 production were evaluated and staining of calcified nodules was performed.

 Results: Increase in ALP activity was observed when using Ga-Al-As lasers of both wavelengths and increased dyeability of von Kossa staining was observed in both the groups. Moreover, the expression level of BMP-2 gene and protein in the 660-nm irradiation group was notably increased, but no significant difference in BMP-2 expression was observed in the 810-nm irradiation group.

 Conclusion: These findings suggest the prospective use of Ga-Al-As lasers to enhance the formation of hard tissue in hDPCs, but also indicate that the expression level of BMP-2 may differ when using lasers at different wavelengths.

 Purpose: Theaflavin, a polyphenol substance extracted from black tea, has several beneficial effects such as anti-cancer, anti-inflammatory, and anti-oxidant effects. However, the effect of theaflavin on the progression of periodontal disease is still unknown. The aim of this study was to examine the effect of theaflavin on chemokine production in IL-27-stimulated human oral epithelial cells. We focused on CXCR3 ligands, CXCL9, CXCL10, and CXCL11 production in TR146.

 Methods: Human oral epithelial cells, TR146 cells, were used in this study. We measured chemokine production in TR146 cells by ELISA. We used Western blot analysis to detect the phosphorylation levels of signal transduction molecules in TR146 cells.

 Results: Theaflavin-3,3’-digallate (TFDG) decreased CXCL9, CXCL10, and CXCL11 production in IL-27-stimulated TR146 cells. Western blot analysis showed TFDG inhibited Akt, ERK, STAT1, and STAT3 phosphorylation in IL-27-treated TR146 cells.

 Conclusion: TFDG suppressed chemokine production in IL-27-stimulated TR146 cells. These data suggest that theaflavin might have a beneficial effect against periodontitis.

 Purpose: In an animal experiment with enamel matrix derivative (EMD), which is commonly used as a material for periodontal tissue regeneration, a substance consistent with the partial sequence of amelogenin exon 5 was identified. Investigators synthesized a peptide with the same amino acid sequence, and examined its usefulness for periodontal tissue regeneration in vivo and in vitro. However, no in vivo experiment has compared the peptide with EMD.

 Materials and Methods: Periodontal tissue defects were artificially prepared in the maxillary molar region of rats, and a new synthetic peptide (new synthetic peptide group) or EMD (EMD group) was applied to the site of defect. Specimens at this site were prepared 3, 5, and 7 days after surgery, and histopathologically and immunohistochemically examined using anti-type III collagen antibody.

 Results: The histopathological findings 3 days after surgery were similar among the control, new synthetic peptide, and EMD groups. Five days after surgery, the disappearance of blood clots at the site of defect was confirmed in the new synthetic peptide and EMD groups, whereas blood clots remained in the control group. Silver impregnation 7 days after surgery showed an osteoid calcified body with reticular fibers at the periphery in both the new synthetic peptide and EMD groups. Immunohistochemically, in the two groups, type III collagen appeared and attenuated earlier than in the control group. In the two groups, the deep epithelial proliferation inhibition rates 5 or 7 days after surgery were significantly lower than in the control group.

 Conclusion: Like EMD, novel synthetic peptide promoted the early wound healing process in periodontal tissues compared to the control, suggesting that it has action to accelerate periodontal regeneration.

 Purpose: The purpose of this study was to evaluate by micro-computed tomography (micro-CT) the cutting efficiency using a nickel-titanium rotary file (NiTi-r), a stainless steel rotary file (SS-r), and a hand file (Hand) for preparation of a root canal in extracted human maxillary premolars placed on the left and right sides of a dental model on a phantom.

 Methods: Twenty-four extracted human maxillary premolars with a buccolingual canal diameter two or more times larger than the mesiodistal canal diameter at 5 mm from the root apex were used in this study. The teeth were placed in the left and right sides of a dental model attached to a training phantom. The operator worked on the phantom clinically in a 9-10 o’clock position. The teeth were divided into three groups of eight teeth each (left: four teeth, right: four teeth) the NiTi-r group (K3XF file), SS-r group (ERT file) and Hand group (K-file) according to the following preparation techniques. Root canal preparation was performed with a brushing stroke in the NiTi-r and SS-r groups, and with circumferential filing in the Hand group. The working time, cutting ratio, and volume increase ratio were calculated and evaluated between groups and the left and right sides by micro-CT.

 Results: Hand had a significantly larger cutting ratio than SS-r, but the working time of Hand was significantly longer. NiTi-r and Hand had similar cutting ratios, but the working time for NiTi-r was significantly shorter. There were no significant differences in the working time, cutting ratio, or volume increase ratio between NiTi-r and SS-r. SS-r and Hand had larger volume increase ratios than NiTi-r, but it was not significant. There were no significant differences in the working time, cutting ratio, or volume increase ratio between the left side tooth and the right side tooth.

 Conclusion: When preparing left and right maxillary premolars with oval-shaped canal on a phantom, NiTi-r can cut efficiently in a short time and with a reasonable shape, the same as Hand files.

 Purpose: The purpose of this study was to compare the total preparation time, the amount of canal transportation and the pushing and pulling forces of the following four files: the single Ni-Ti file system (RECIPROC: RE), multi Ni-Ti files system (Twisted File: TF and ProTaper: PT) and stainless steel multi-file system (K-file: SSK).

 Methods: Thirty-six transparent resin models which had curved root canals of 30 degrees were used (n=9, each). Photographs taken before and after preparation of the canal were superimposed. The amounts of canal transportation were measured at 1-mm intervals from the apical foramen to the 9 mm level. The total preparation time, and the forces required for push load and pull-out load during root canal preparation were measured. The data were analyzed by Games-Howell’s method after one-way ANOVA.

 Results: The total preparation time was short in the order of TF, RE, PT and SSK and significant differences were observed between each group. There was no significant difference in the amount of canal transportation between all groups at 0 and 1 mm from the apex. At 2 and 3 mm, significant differences were observed between RE and TF, PT, and also SSK and TF, PT. At 4 mm, significant differences were observed between RE and TF, PT, and also SSK and TF, PT, in addition to TF and PT. At 5 mm, significant differences were observed between RE and TF, PT. At 6 mm, significant differences were observed between RE and other groups, and also SSK and other groups. At 7 mm, significant differences were observed between SSK and other groups, and also TF and PT. At 8 and 9 mm, significant differences were observed between SSK and other groups. The pushing and pulling forces were greatest in SSK and were smaller in the order of RE, PT and TF. The pushing forces indicated significant differences between all groups, however, the pulling forces showed no significant difference between TF and PT.

 Conclusion: The single-file system using RECIPROC has higher shaping ability than the multi-file system, however, the inner side of the apical area was removed in the curved canals, suggesting that the prevention of strip perforation is needed when using RECIPROC.

 Objective: Clear evidence of the association between temporomandibular disorder and traumatic occlusion has not been obtained. However, when temporomandibular disorder and occlusal trauma occur ipsilaterally at the same time, some relationship is suspected. Here we report a case in which favorable results were obtained using comprehensive therapy for a patient with severe chronic periodontitis and temporomandibular joint disorder.

 Case: A 32-year-old female patient diagnosed with severe chronic periodontitis with traumatic occlusion and temporomandibular joint (TMJ) disorder on the right side. Manipulation and an occlusal splint were provided as TMJ treatment. After periodontal treatment, orthodontic treatment and occlusal reconstruction by a crown prosthesis were performed. Comprehensive therapy improved the periodontal tissue and occlusion. During the period of supportive periodontal therapy (SPT), relapse of TMJ disorder was recognized in the right side. By retreatment of the temporomandibular disorder, the periodontium was maintained in a stable state without destruction.

 Conclusion: Patients with periodontitis and TMJ disorders may suffer traumatic occlusion due to unstable mandibular movement. Such cases need careful examination and management of TMJ and occlusion.