Publications by authors named "Chiaki Kitamura"

54 Publications

Odontoblast differentiation is regulated by an interplay between primary cilia and the canonical Wnt pathway.

Bone 2021 May 8;150:116001. Epub 2021 May 8.

Department of Anatomy and Cell Biology, University of Yamanashi Faculty of Medicine, 1110, Shimo-Kateau, Chuo, Yamanashi 4093898, Japan. Electronic address:

Primary cilium is a protruding cellular organelle that has various physiological functions, especially in sensory reception. While an avalanche of reports on primary cilia have been published, the function of primary cilia in dental cells remains to be investigated. In this study, we focused on the function of primary cilia in dentin-producing odontoblasts. Odontoblasts, like most other cell types, possess primary cilia, which disappear upon the knockdown of intraflagellar transport protein 88. In cilia-depleted cells, the expression of dentin sialoprotein, an odontoblastic marker, was elevated, while the deposition of minerals was slowed. This was recapitulated by the activation of canonical Wnt pathway, also decreased the ratio of ciliated cells. In dental pulp cells, as they differentiated into odontoblasts, the ratio of ciliated cells was increased, whereas the canonical Wnt signaling activity was repressed. Our results collectively underscore the roles of primary cilia in regulating odontoblastic differentiation through canonical Wnt signaling. This study implies the existence of a feedback loop between primary cilia and the canonical Wnt pathway.
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http://dx.doi.org/10.1016/j.bone.2021.116001DOI Listing
May 2021

Effects of Both Fiber Post/Core Resin Construction System and Root Canal Sealer on the Material Interface in Deep Areas of Root Canal.

Materials (Basel) 2021 Feb 19;14(4). Epub 2021 Feb 19.

Division of Endodontics and Restorative Dentistry, Department of Oral Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan.

This study aimed to examine the resin polymerization of a fiber post/core resin construction system and the interface between resin and root canal sealers, which are important for root canal sealing. We used the i-TFC Luminus fiber post and i-TFC Luminus LC flow (i-TFC-L), the GC fiber post and Unifil Core EM (GCF), and the FiberKor post and Build-It FR (FKP) as core construction systems, and Nishika Canal Sealer BG (CS-BG), Metaseal Soft (META), and Nishika Canal Sealer EN (CS-EN) as sealers. The light transmission of fiber posts (n = 5), the polymerization of core resin (n = 5), and the adhesion between the sealer and core resin (n = 10) were evaluated. The i-TFC Luminus fiber post light transmission was significantly higher than that of other posts. Without shielding, i-TFC-L showed a significantly greater amount of polymerized resin than the other systems. With shielding, although i-TFC-L showed a significantly greater amount of polymerized resin immediately after light irradiation, polymerized resin was significantly greater in GCF and FKP after 10 min. All systems adhered to CS-BG and META but not to CS-EN. These results indicate that resin polymerization in the cavity differs among fiber post/core resin construction systems and that the adhesion of the resin and sealer depends on the property of the sealer.
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http://dx.doi.org/10.3390/ma14040982DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923224PMC
February 2021

Effect of Bioactive Glass-Based Root Canal Sealer on the Incidence of Postoperative Pain after Root Canal Obturation.

Int J Environ Res Public Health 2020 11 28;17(23). Epub 2020 Nov 28.

Division of Endodontics and Restorative Dentistry, Department of Oral Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan.

The purpose of this study is to evaluate the effect of a bioactive glass-based root canal sealer, Nishika Canal Sealer BG (CS-BG), on the incidence of postoperative pain (PP) after root canal obturation (RCO). Eleven dentists performed pulpectomy or infected root canal treatments for 555 teeth. During RCO, CS-BG was used. After RCO, the rate of PP and the factors affecting PP (pain during RCO and pain immediately after RCO) were analyzed. PP was observed in eight teeth (1.5%), and within 7 days after RCO, there were no teeth with pain. In these teeth with PP, there was a significant difference in the occurrence of pain during RCO, but not in the occurrence of pain immediately after RCO, when compared with pulpectomy and infected root canal treatment. These clinical results show that CS-BG has an excellent biocompatibility, and can suppress the distress of patients during RCO.
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http://dx.doi.org/10.3390/ijerph17238857DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7730492PMC
November 2020

A small nuclear acidic protein (MTI-II, Zn-binding protein, parathymosin) attenuates TNF-α inhibition of BMP-induced osteogenesis by enhancing accessibility of the Smad4-NF-κB p65 complex to Smad binding element.

Mol Cell Biochem 2020 Jun 18;469(1-2):133-142. Epub 2020 Apr 18.

Division of Endodontics and Restorative Dentistry, Department of Oral Function, Kyushu Dental University, Fukuoka, 803-8580, Japan.

Pro-inflammatory cytokines prevent bone regeneration in vivo and activation of nuclear factor-κB (NF-κB) signaling has been proposed to lead to suppression of bone morphogenetic protein (BMP)-induced osteogenesis via direct binding of p65 to Smad4 in vitro. Application of a small nuclear acidic protein (MTI-II) and its delivered peptide, MPAID (MTI-II peptide anti-inflammatory drug) has been described to elicit therapeutic potential via strong anti-inflammatory action following the physical association of MTI-II and MPAID with p65. However, it is unclear whether MTI-II attenuates tumor necrosis factor (TNF)-α inhibition of BMP-induced osteogenesis. Herein, we found that TNF-α-mediated suppression of responses associated with BMP4-induced osteogenesis, including expression of the osteocalcin encoding gene Ocn, Smad binding element (SBE)-dependent luciferase activity, alkaline phosphatase activity, and alizarin red S staining were largely restored by MTI-II and MPAID in MC3T3-E1 cells. Mechanistically, MTI-II and MPAID did not inhibit nuclear translocation of p65 or disassociate Smad4 from p65. Further, results from chromatin immunoprecipitation (ChIP) analyses revealed that Smad4 enrichment in cells over-expressing MTI-II and treated with TNF-α was equivalent to that in cells without TNF-α treatment. Alternatively, Smad4 enrichment was considerably decreased following TNF-α treatment in control cells. Moreover, p65 enrichment in the Id-1 promoter SBE was detected only when cells over-expressing MTI-II were stimulated with TNF-α. Overall, our study concludes that MTI-II restored TNF-α-inhibited suppression of BMP-Smad-induced osteogenic differentiation by enhancing accessibility of the Smad4-p65 complex to the SBE rather than by liberating Smad4 from p65.
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http://dx.doi.org/10.1007/s11010-020-03734-6DOI Listing
June 2020

A novel inhibitor of NF-κB-inducing kinase prevents bone loss by inhibiting osteoclastic bone resorption in ovariectomized mice.

Bone 2020 Jun 10;135:115316. Epub 2020 Mar 10.

Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Oral Health/Brain Health/Total Health Research Center, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address:

Musculoskeletal diseases and disorders, including osteoporosis and rheumatoid arthritis are diseases that threaten a healthy life expectancy, and in order to extend the healthy life expectancy of elderly people, it is important to prevent bone and joint diseases and disorders. We previously reported that alymphoplasia (aly/aly) mice, which have a loss-of-function mutation in the Nik gene involved in the processing of p100 to p52 in the alternative NF-κB pathway, show mild osteopetrosis with a decrease in the osteoclast number, suggesting that the alternative NF-κB pathway is a potential drug target for ameliorating bone diseases. Recently, the novel NF-κB-inducing kinase (NIK)-specific inhibitor compound 33 (Cpd33) was developed, and we examined its effect on osteoclastic bone resorption in vitro and in vivo. Cpd33 inhibited the receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis accompanied by a decrease in the expression of nfatc1, dc-stamp, and cathepsin K, markers of osteoclast differentiation, without affecting the cell viability, in a dose-dependent manner. Cdp33 specifically suppressed the RANKL-induced processing of p100 to p52 but not the phosphorylation of p65 or the degradation or resynthesis of IκBα in osteoclast precursors. Cpd33 also suppressed the bone-resorbing activity in mature osteoclasts. Furthermore, Cdp33 treatment prevented bone loss by suppressing the osteoclast formation without affecting the osteoblastic bone formation in ovariectomized mice. Taken together, NIK inhibitors may be a new option for patients with a reduced response to conventional pharmacotherapy or who have serious side effects.
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http://dx.doi.org/10.1016/j.bone.2020.115316DOI Listing
June 2020

Caffeic Acid Phenethyl Ester (CAPE) Induces VEGF Expression and Production in Rat Odontoblastic Cells.

Biomed Res Int 2019 20;2019:5390720. Epub 2019 Dec 20.

Department of Conservative Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan.

Caffeic acid phenethyl ester (CAPE), the main component of propolis, has various biological activities including anti-inflammatory effect and wound healing promotion. Odontoblasts located in the outermost layer of dental pulp play crucial roles such as production of growth factors and formation of hard tissue termed reparative dentin in host defense against dental caries. In this study, we investigated the effects of CAPE on the upregulation of vascular endothelial growth factor (VEGF) and calcification activities of odontoblasts, leading to development of novel therapy for dental pulp inflammation caused by dental caries. CAPE significantly induced mRNA expression and production of VEGF in rat clonal odontoblast-like KN-3 cells cultured in normal medium or osteogenic induction medium. CAPE treatment enhanced nuclear factor-kappa B (NF-B) transcription factor activation, and furthermore, the specific inhibitor of NF-B significantly reduced VEGF production. The expression of VEGF receptor- (VEGFR-) 2, not VEGFR-1, was up regulated in KN-3 cells treated with CAPE. In addition, VEGF significantly increased mineralization activity in KN-3 cells. These findings suggest that CAPE might be useful as a novel biological material for the dental pulp conservative therapy.
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http://dx.doi.org/10.1155/2019/5390720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6942799PMC
June 2020

Concordance study between regular face-to-face dental diagnosis and dental telediagnosis using fluorescence.

J Telemed Telecare 2020 Jan 5:1357633X19894111. Epub 2020 Jan 5.

Department of Oral Public Health, Montpellier University Hospital, France.

Background: Teledentistry consultations are an effective way to increase access to care. Whether it be for a screening, referral or even an adapted treatment plan for a certain number of patients whose access to care is complicated, demonstrating the reliability of remote consultations is essential in allowing the technique to become generalised.

Aim: This study aimed to determine if teledentistry consultations using fluorescence are of the same quality as regular consultations in the diagnosis of caries.

Methods: Patients were seen in consultation in the dental care centre at the Montpellier University Hospital (France) and in the centre at Kyushu Dental University Hospital (Japan). The protocol was broken down into three parts: the regular consultation, the recording of videos with the Soprocare camera and the remote consultation. The regular consultation and the remote consultation were blinded and carried out by two different dentists. The recording of videos was carried out by a third dentist. The carious diagnosis was based on the International Caries Detection and Assessment System: a clinical rating system for the detection and assessment of caries.

Results: One hundred and ninety-five patients met the predefined inclusion criteria. Most patients had at least one surface at stage 3 or higher (73%) with a higher proportion amongst French patients (81% compared to 66%). However, they had good dental hygiene, given that dental hygiene was only deemed unsatisfactory for 10.8% (19% for French patients and 2% for Japanese patients). The odontogram (presence/absence of each tooth) seemed to be correctly identified during the remote consultation (reinterpretation). Out of the 195 patients, 168 (86.2%) were identified without error.

Conclusions: Teledentistry consultations can represent acceptable diagnostic performance with regard to the detection of dental caries. The Soprocare camera enables an early diagnosis of carious lesions with optimal efficiency. Several areas still need to be improved, however, so that the use of the camera during remote consultations is as coherent and effective as possible, especially with regard to the organisational aspects of remote consultations.
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http://dx.doi.org/10.1177/1357633X19894111DOI Listing
January 2020

Bioactive Glass-Based Endodontic Sealer as a Promising Root Canal Filling Material without Semisolid Core Materials.

Materials (Basel) 2019 Nov 29;12(23). Epub 2019 Nov 29.

Division of Endodontics and Restorative Dentistry, Department of Oral Functions, Kyushu Dental University, Kitakyushu 803-8580, Japan.

Endodontic treatment for a tooth with damaged dental pulp aims to both prevent and cure apical periodontitis. If the tooth is re-infected as a result of a poorly obturated root canal, periapical periodontitis may set-in due to invading bacteria. To both avoid any re-infection and improve the success rate of endodontic retreatment, a treated root canal should be three-dimensionally obturated with a biocompatible filling material. Recently, bioactive glass, one of the bioceramics, is focused on the research area of biocompatible biomaterials for endodontics. Root canal sealers derived from bioactive glass-based have been developed and applied in clinical endodontic treatments. However, at present, there is little evidence about the patient outcomes, sealing mechanism, sealing ability, and removability of the sealers. Herein, we have developed a bioactive glass-based root canal sealer and provided evidence concerning its physicochemical properties, biocompatibility, sealing ability, and removability. We also review the classification of bioceramics and characteristics of bioactive glass. Additionally, we describe the application of bioactive glass to facilitate the development of a new root canal sealer. Furthermore, this review shows the potential application of bioactive glass-based cement as a root canal filling material in the absence of semisolid core material.
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http://dx.doi.org/10.3390/ma12233967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6926972PMC
November 2019

Adhesive bonding of alumina air-abraded Ag-Pd-Cu-Au alloy with 10-methacryloyloxydecyl dihydrogen phosphate.

Dent Mater J 2020 Mar 13;39(2):262-271. Epub 2019 Nov 13.

Division of Biomaterials, Department of Oral Functions, Kyushu Dental University.

The aim of this paper is to study changes in the Ag-Pd-Cu-Au alloy surfaces by alumina air-abrasion process and effect of those changes on the adhesive bonding characteristic. Surface roughness, surface composition and chemical state of the alumina air-abraded alloys were analyzed by a confocal laser scanning microscope, an energy dispersive X-ray spectroscopy and an X-ray photoelectron spectroscopy. The results showed that the alumina air-abrasion changed the alloy surface by mechanical roughening, alumina remain and copper oxidation. Effect of the changes in the alloy surface on the adhesive bonding characteristic was examined by using a methyl methacrylate/tri-n-butylborane derivative (MMA/TBB) resin cement with the 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer. The shear bond strength test results indicated that the surface oxidation by the abrasion is the main contributor that improved the adhesive bonding rather than other effects such as mechanical roughening or alumina remain.
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http://dx.doi.org/10.4012/dmj.2019-027DOI Listing
March 2020

Expression and function of dopamine in odontoblasts.

J Cell Physiol 2020 05 15;235(5):4376-4387. Epub 2019 Oct 15.

Department of Endodontology and Operative Dentistry, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.

Dopamine (DA) is produced from tyrosine by tyrosine hydroxylase (TH). A recent study has reported that DA promotes the mineralization of murine preosteoblasts. However, the role of DA in odontoblasts has not been examined. Therefore, in this investigation, we researched the expression of TH and DA in odontoblasts and the effects of DA on the differentiation of preodontoblasts (KN-3 cells). Immunostaining showed that TH and DA were intensely expressed in odontoblasts and preodontoblasts of rat incisors and molars. KN-3 cells expressed D1-like and D2-like receptors for DA. Furthermore, DA promoted odontoblastic differentiation of KN-3 cells, whereas an antagonist of D1-like receptors and a PKA signaling blocker, inhibited such differentiation. However, antagonists of D2-like receptors promoted differentiation. These results suggested that DA in preodontoblasts and odontoblasts might promote odontoblastic differentiation through D1-like receptors, but not D2-like receptors, and PKA signaling in an autocrine or paracrine manner and plays roles in dentinogenesis.
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http://dx.doi.org/10.1002/jcp.29314DOI Listing
May 2020

Chemical alteration of Ag-Pd-Cu-Au alloy surface by alumina air-abrasion and its effect on bonding to resin cement.

Dent Mater J 2019 Jul 9;38(4):630-637. Epub 2019 Apr 9.

Division of Biomaterials, Department of Oral Functions, Kyushu Dental University.

The goal of this study was to investigate the chemical alteration of a dental alloy surface by alumina air-abrasion and its effect on bonding to resin cement. Alumina air-abrasion was carried out on an Ag-Pd-Cu-Au alloy. The surface morphology and chemical state of the abraded alloy were characterized. The effect of the air-abrasion on the shear bond strength between the alloy and a methyl methacrylate/tri-n-butyl borane (MMA/TBB) resin cement with some primers was evaluated. The surface characterization revealed that the alumina air-abrasion mechanically roughened and chemically altered the surface. The chemical alterations had two effects: (1) abraded alumina particles remained on the alloy surface and (2) copper ions were oxidized in the alloy surface. As the result, the shear bond strength test indicated that 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer worked with the abraded alloy surface, whereas it did not work with the non-abraded alloy surface.
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http://dx.doi.org/10.4012/dmj.2018-276DOI Listing
July 2019

Current and future options for dental pulp therapy.

Jpn Dent Sci Rev 2019 Nov 29;55(1):5-11. Epub 2018 Sep 29.

Division of Endodontics and Restorative Dentistry, Department of Science of Oral Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.

Dental pulp is a connective tissue and has functions that include initiative, formative, protective, nutritive, and reparative activities. However, it has relatively low compliance, because it is enclosed in hard tissue. Its low compliance against damage, such as dental caries, results in the frequent removal of dental pulp during endodontic therapy. Loss of dental pulp frequently leads to fragility of the tooth, and eventually, a deterioration in the patient's quality of life. With the development of biomaterials such as bioceramics and advances in pulp biology such as the identification of dental pulp stem cells, novel ideas for the preservation of dental pulp, the regenerative therapy of dental pulp, and new biomaterials for direct pulp capping have now been proposed. Therapies for dental pulp are classified into three categories; direct pulp capping, vital pulp amputation, and treatment for non-vital teeth. In this review, we discuss current and future treatment options in these therapies.
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http://dx.doi.org/10.1016/j.jdsr.2018.09.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6354285PMC
November 2019

Preparation of gelatin hydrogel sponges incorporating bioactive glasses capable for the controlled release of fibroblast growth factor-2.

J Biomater Sci Polym Ed 2019 01 2;30(1):49-63. Epub 2019 Jan 2.

c Laboratory of Biomaterials, Department of Regeneration Science and Engineering , Institute for Frontier Life and Medical Sciences, Kyoto University , Kyoto , Japan.

Gelatin hydrogel sponges incorporating bioactive glasses (Gel-BG) were fabricated. We evaluated the characteristics of Gel-BG as scaffolds from the perspective of their mechanical properties and the formation of hydroxyapatite by the incorporation of bioactive glasses (BG). In addition, the Gel-BG degradation and the profile of fibroblast growth factor-2 (FGF-2) release from the Gel-BG were examined. Every Gel-BG showed an interconnected pore structure with the pore size range of 180-200 µm. The compression modulus of sponges incorporating BG increased. The time profiles of degradation for the 72-h crosslinked gelatin hydrogel sponges incorporating 10 wt% BG (Gel-BG(10)) and 50 wt% BG (Gel-BG(50)) were analogous to that of the 24-h crosslinked gelatin hydrogel sponge without BG (Gel-BG(0)). In measuring the release of FGF-2 from Gel-BG, the Gel-BG(10) and Gel-BG(50) showed almost analogous 100% cumulative release within 28 days in vivo. Additionally, a bioactivity evaluation showed that the presence of gelatin does not affect the in vitro bioactivity of Gel-BG. These sponges showed mechanical and chemical functionality as scaffolds, featuring both the controlled release of FGF-2 and the induction of hydroxyapatite crystallization.
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http://dx.doi.org/10.1080/09205063.2018.1544474DOI Listing
January 2019

In Vitro Evaluation of a Novel Root Canal Endoscope for Visualizing the Apex of Curved Root Canal Models and an Extracted Tooth.

J Endod 2018 Dec 1;44(12):1856-1861. Epub 2018 Nov 1.

Division of Endodontics and Restorative Dentistry, Department of Oral Functions, Kyushu Dental University, Kitakyushu, Fukuoka, Japan. Electronic address:

Introduction: In straight root canals, intraradicular structures around the root canal orifice and apical foramen can be visualized with a dental operating microscope and commercially available root canal endoscopes. However, the root apex area, including the apical foramen, in a curved root canal cannot be visualized using these devices. In the present study, the potential of a newly developed root canal endoscope implementing an image fiber was examined in 3 types of root canal models and extracted teeth.

Methods: A straight and 2 curved (10° and 30°) resin block models were prepared. A resolution chart was set at the outer surface of the apical foramen in each model. Using the microscope and the endoscope, the resolution chart was observed, and the captured images were analyzed quantitatively. Additionally, fracture lines in 20 extracted teeth were observed with both devices.

Results: With the dental operating microscope, a resolution chart line was clearly observed in the straight canal model with 18.0 line pairs/mm resolution and an observing capability of 0.16 at 40 × magnification but not in the curved root canal models. With the root canal endoscope, resolution charts in all types of root canal models were visualized, and the resolution and observing capability were 16.0 line pairs/mm and 0.053, respectively. Fracture lines and the apical foramen of the extracted teeth were observed more clearly with the endoscope than the microscope.

Conclusions: The newly developed root canal endoscope using an image fiber is useful for accurate visualization of the apex area of curved root canals.
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http://dx.doi.org/10.1016/j.joen.2018.08.014DOI Listing
December 2018

Endoscopic System Based on Intraoral Camera and Image Processing.

IEEE Trans Biomed Eng 2019 04 20;66(4):1026-1033. Epub 2018 Aug 20.

Objective: In dentistry, dentists perform many treatments with a few visually magnified information. About deep area of root canals, it commonly relies on exploration carried out with the fingers of the dentist, because the root canal entrance is very small to be observed. In clinical practice, the intraoral camera and endoscopic systems are separate devices, and there are no sensors to capture both pictures of the whole tooth and those inside the root canal. Objective of this research is to combine the intraoral camera and endoscopic system facilitating to use clinical practice.

Methods: We propose an endoscopic system based on the thin image fiber, SOPROLIFE intraoral camera as an image sensor, and a new adaptor to connect the two parts. We observed resolution charts with 50, 25, 10, and 5 line pairs (LP)/mm patterns. The acquired images are processed to both remove fixed-pattern noise using robust principal component analysis and enhance contrast.

Results: The acquired images containing all LP/mm patterns were clear and showed higher contrast after processing. Visibility of the processed images is 1.7, 1.6, 2.2, and 1.9 times higher than that of the raw images for 50, 25, 10, and 5 LP/mm patterns, respectively.

Conclusion: Our fabricated endoscopic system based on the SOPROLIFE intraoral camera could observe 50, 25, 10, and 5 LP/mm patterns. After image processing, the noise was reduced, and high-contrast images were obtained.

Significance: This system can be considered as a further step toward facilitating noninvasive and contactless systems in clinical practice.
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http://dx.doi.org/10.1109/TBME.2018.2866273DOI Listing
April 2019

A peptide that blocks the interaction of NF-κB p65 subunit with Smad4 enhances BMP2-induced osteogenesis.

J Cell Physiol 2018 09 16;233(9):7356-7366. Epub 2018 Apr 16.

Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan.

Bone morphogenetic protein (BMP) potentiates bone formation through the Smad signaling pathway in vitro and in vivo. The transcription factor nuclear factor κB (NF-κB) suppresses BMP-induced osteoblast differentiation. Recently, we identified that the transactivation (TA) 2 domain of p65, a main subunit of NF-κB, interacts with the mad homology (MH) 1 domain of Smad4 to inhibit BMP signaling. Therefore, we further attempted to identify the interacting regions of these two molecules at the amino acid level. We identified a region that we term the Smad4-binding domain (SBD), an amino-terminal region of TA2 that associates with the MH1 domain of Smad4. Cell-permeable SBD peptide blocked the association of p65 with Smad4 and enhanced BMP2-induced osteoblast differentiation and mineralization without affecting the phosphorylation of Smad1/5 or the activation of NF-κB signaling. SBD peptide enhanced the binding of the BMP2-inudced phosphorylated Smad1/5 on the promoter region of inhibitor of DNA binding 1 (Id-1) compared with control peptide. Although SBD peptide did not affect BMP2-induced chondrogenesis during ectopic bone formation, the peptide enhanced BMP2-induced ectopic bone formation in subcortical bone. Thus, the SBD peptide is useful for enabling BMP2-induced bone regeneration without inhibiting NF-κB activity.
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http://dx.doi.org/10.1002/jcp.26571DOI Listing
September 2018

In vitro and in vivo effects of a novel bioactive glass-based cement used as a direct pulp capping agent.

J Biomed Mater Res B Appl Biomater 2019 01 25;107(1):161-168. Epub 2018 Mar 25.

Division of Endodontics and Restorative Dentistry, Department of Science of Oral Functions, Kyushu Dental University, Fukuoka, Japan.

Direct pulp capping is an important procedure for preserving pulp viability. The pulp capping agent must possess several properties, including usability, biocompatibility, and the ability to induce reparative dentin formation. In this study, a novel bioactive glass-based cement was examined to determine whether the cement has the necessary properties to act as a direct pulp capping agent. Physicochemical properties of the bioactive glass-based cement and in vitro effects of the cement on odontoblast-like cells, as well as in vivo effects on the exposed dental pulp, were analyzed. The cement immersed in water stabilized at pH10, and hydroxyapatite-like precipitation was induced on the surface of the cement in simulate body fluid. There were no cytotoxic effects on the viability, alkaline phosphatase activity, or calcium deposition ability of odontoblast-like cells. In the in vivo rat study of an exposed dental pulp model, the cement induced a sufficient level of reparative dentin formation by odontoblast-like cells expressing odontoblastic markers at the exposed area of the dental pulp. These results suggest that the newly developed bioactive glass-based cement provides favorable biocompatibility with the dental pulp and may be useful as a direct pulp capping agent. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 161-168, 2019.
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http://dx.doi.org/10.1002/jbm.b.34107DOI Listing
January 2019

Celecoxib inhibits osteoblast differentiation independent of cyclooxygenase activity.

Clin Exp Pharmacol Physiol 2018 Jan 20;45(1):75-83. Epub 2017 Sep 20.

Division of Applied Pharmacology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Japan.

Non-steroidal anti-inflammatory drugs (NSAIDs) exert their effects primarily by inhibiting the activity of cyclooxygenase (COX), thus suppressing prostaglandin synthesis. Some NSAIDs are known to perform functions other than pain control, such as suppressing tumour cell growth, independent of their COX-inhibiting activity. To identify NSAIDs with COX-independent activity, we examined various NSAIDs for their ability to inhibit osteoblastic differentiation using the mouse pre-osteoblast cell line MC3T3-E1. Only celecoxib and valdecoxib strongly inhibited osteoblastic differentiation, and this effect was not correlated with COX-inhibiting activity. Moreover, 2,5-dimethyl (DM)-celecoxib, a celecoxib analogue that does not inhibit COX activity, also inhibited osteoblastic differentiation. Celecoxib and DM-celecoxib inhibited osteoblastic differentiation induced by bone morphogenetic protein (BMP)-2 in C2C12 mouse myoblast cell line. Although celecoxib suppresses the growth of some tumour cells, the viability and proliferation of MC3T3-E1 cells were not affected by celecoxib or DM-celecoxib. Instead, celecoxib and DM-celecoxib suppressed BMP-2-induced phosphorylation of Smad1/5, a major downstream target of BMP receptor. Although it is well known that COX plays important roles in osteoblastic differentiation, these results suggest that some NSAIDs, such as celecoxib, have targets other than COX and regulate phospho-dependent intracellular signalling, thereby modifying bone remodelling.
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http://dx.doi.org/10.1111/1440-1681.12846DOI Listing
January 2018

Ameloblastin Upregulates Inflammatory Response Through Induction of IL-1β in Human Macrophages.

J Cell Biochem 2017 10 3;118(10):3308-3317. Epub 2017 May 3.

Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu 803-8580, Japan.

Ameloblastin (AMBN) is an enamel matrix protein that has various biological functions such as healing dental pulp and repairing bone fractures. In the present study, we clarified the effect of AMBN on the expression of an inflammatory cytokine, interleukin-1β (IL-1β) in lipopolysaccharide (LPS)-treated human macrophages. Real-time RT-PCR analysis showed that LPS treatment upregulated expression of the IL-1β gene in U937 cells. Interestingly, AMBN significantly enhanced IL-1β gene expression in LPS-treated U937 cells as well as the secretion of mature IL-1β into culture supernatants by these cells. AMBN also activated caspase-1 p10 expression in LPS-treated U937 cells. Pretreatment with a caspase-1 inhibitor, Z-YVAD-FMK, downregulated the mature IL-1β expression enhanced by AMBN treatment in LPS-treated U937 cells. A co-immunoprecipitation assay showed that treatment with LPS and AMBN upregulated toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) interactions, but there was no significant difference compared with LPS treatment alone in U937 cells. In contrast, western blot analysis revealed that AMBN remarkably prolonged the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), a member of the mitogen-activated protein kinase (MAPK) family. An ERK1/2-selective inhibitor, U0126, suppressed expression of the IL-1β gene as well as its protein expression in U937 cells treated with LPS and AMBN. Taken together, these results indicate that AMBN enhances IL-1β production in LPS-treated U937 cells through ERK1/2 phosphorylation and caspase-1 activation, suggesting that AMBN upregulates the inflammatory response in human macrophages and plays an important role in innate immunity. J. Cell. Biochem. 118: 3308-3317, 2017. © 2017 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jcb.25983DOI Listing
October 2017

Functional Roles of NOD1 in Odontoblasts on Dental Pulp Innate Immunity.

Biomed Res Int 2016 25;2016:9325436. Epub 2016 Sep 25.

Department of Conservative Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan.

Caries-related pathogens are first recognized by odontoblasts and induce inflammatory events that develop to pulpitis. Generally, initial sensing of microbial pathogens is mediated by pattern recognition receptors, such as Toll-like receptor and nucleotide-binding oligomerization domain (NOD); however, little is known about NODs in odontoblasts. In this study, the levels of NODs expressed in rat odontoblastic cell line, KN-3, were assessed by flow cytometry and the levels of chemokines in NOD-specific ligand-stimulated KN-3 cells were analyzed by real-time PCR and ELISA. The signal transduction pathway activated with NOD-specific ligand was assessed by blocking assay with specific inhibitors and reporter assay. In KN-3 cells, the expression level of NOD1 was stronger than that of NOD2 and the production of chemokines, such as CINC-1, CINC-2, CCL20, and MCP-1, was upregulated by stimulation with NOD1-specific ligand, but not with NOD2-specific ligand. CINC-2 and CCL20 production by stimulation with NOD1-specific ligand was reduced by p38 MAPK and AP-1 signaling inhibitors. Furthermore, the reporter assay demonstrated AP-1 activation in NOD1-specific ligand-stimulated KN-3 cells. These findings indicated that NOD1 expressed in odontoblasts functions to upregulate the chemokines expression via p38-AP-1 signaling pathway and suggested that NOD1 may play important roles in the initiation and progression of pulpitis.
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http://dx.doi.org/10.1155/2016/9325436DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5055926PMC
February 2017

A Small Nuclear Acidic Protein (MTI-II, Zn Binding Protein, Parathymosin) That Inhibits Transcriptional Activity of NF-κB and Its Potential Application to Antiinflammatory Drugs.

Endocrinology 2016 Dec 14;157(12):4973-4986. Epub 2016 Oct 14.

Departments of Clinical Proteomics and Molecular Medicine (K.Ok., K.Om., T.S., M.A., N.S., T.K.) and Disease Biomarker Analysis and Molecular Regulation (M.S.K.), St Marianna University Graduate School of Medicine, Kawasaki, Kanagawa 216-8511, Japan; Department of Biological Endodontics (S.H.-T.), Institute of Biomedical and Health Science, Hiroshima University, Hiroshima 734-8553, Japan; and Division of Endodontics and Restorative Dentistry (C.K.), Kyushu Dental University, Kitakyushu, Fukuoka 803-8580, Japan.

Nuclear factor-κB (NF-κB) is the most potent proinflammatory transactivator, and an inhibitor of NF-κB is a good antiinflammatory drug. Glucocorticoids (GCs) are the strongest and the most frequently used antiinflammatory drugs. GC-bound glucocorticoid receptor (GR) inhibits the transcriptional activity of NF-κB and thereby suppresses a broad range of inflammatory processes. Concurrently, in whole body outside the inflammation area, the GR exerts a lot of hormone action, which results in severe side effects. There is a long-awaited need for a new NF-κB inhibitor. Previously we found a small nuclear acidic protein (named MTI-II, also known as Zn-binding protein or parathymosin), which worked as a coactivator of GR. Here we showed that overexpression of MTI-II inhibited a transcriptional activity of NF-κB independently of GCs and the GR. Vise versa, RNA interference suppression of inherent MTI-II enhanced the transcriptional activity of NF-κB. An immunoprecipitation analysis showed that MTI-II precipitated NF-κB after the stimulation of TNFα. Deletion mutants of MTI-II showed that central acidic region is essential for the inhibition of the transcriptional activity of NF-κB. These results suggest that MTI-II would be an inherent inhibitor that interacts with NF-κB. Next, we constructed MTI-II-based antiinflammatory drugs (three fusion proteins of MTI-II with a protein transduction domain and a fusion peptide of the central acidic region with protein transduction domain). These drugs had significant antiinflammatory effects on acute inflammation models and on animal models of human chronic inflammation diseases without an increase of the blood glucose level and repeated-dose toxicity. The MTI-II-based antiinflammatory drug will be a good alternative of GCs.
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http://dx.doi.org/10.1210/en.2016-1746DOI Listing
December 2016

Two-year clinical comparison of a flowable-type nano-hybrid composite and a paste-type composite in posterior restoration.

J Investig Clin Dent 2017 Aug 5;8(3). Epub 2016 Jul 5.

Department of Oral Functions, Division of Endodontics and Restorative Dentistry, Kyushu Dental University, Kitakyushu, Fukuoka, Japan.

Aim: The purpose of the present study was to compare the clinical efficacy between a flowable-type nano-hybrid composite and a paste-type composite for posterior restoration.

Methods: Of 62 posterior teeth in 33 patients (mean age: 34.1 years), 31 were filled with a paste-type composite (Heliomolar [HM] group), and another 31 with a flowable nano-hybrid composite (MI FIL [MI] group). Clinical efficacy was evaluated at 2 years after the restoration.

Results: There were no differences for retention, surface texture deterioration, anatomical form change, deterioration of marginal adaptation, and secondary caries, while a statistical difference was found for marginal discoloration, which was significantly greater in the HM group (P < 0.05). Furthermore, color matching in the MI group was superior to that in the HM group immediately after the restoration throughout the study period.

Conclusions: The present 2-year clinical evaluation of different composites showed that the flowable nano-hybrid composite could be an effective esthetic material for posterior restoration.
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http://dx.doi.org/10.1111/jicd.12227DOI Listing
August 2017

Effects of 4-META/MMA-TBB Resin at Different Curing Stages on Osteoblasts and Gingival Epithelial Cells.

J Adhes Dent 2016 ;18(2):111-8

Purpose: To assess the effects of different curing stages of 4-META/MMA-TBB resin on osteoblasts and gingival keratinocytes.

Materials And Methods: The MC3T3-E1 murine pre-osteoblastic cell line and GE-1 murine gingival epithelial cell line were cultured with mixtures of Super-Bond C&B at different curing stages, and the cell viability was assessed. The alkaline phosphatase (ALP) activity of the MC3T3-E1 cells was also assessed.

Results: The majority of the MC3T3-E1 cells died and showed no ALP activity when cultured with 4-META/MMA-TBB resin during the initial curing phase (1 min of curing). A later curing phase of the 4-META/MMA-TBB resin (7 min of curing) showed cytotoxicity at day 1, but the toxic effect was temporary and the proliferative capacity and ALP activity in the cells were similar to control cells at day 7. Completely cured 4-META/MMA-TBB resin (after 1 or 12 h of curing) did not affect the cell viability or ALP activity of the MC3T3-E1 cells. In contrast, 4-META/MMA-TBB resin showed no effect on the GE-1 cells at any stage of curing.

Conclusion: Although 4-META/MMA-TBB resin during the initial curing phase shows toxic effects on MC3T3-E1 cells, that cytotoxicity is minimal at later curing phases. In contrast, neither the uncured nor cured resins affected the GE-1 cells.
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http://dx.doi.org/10.3290/j.jad.a35839DOI Listing
July 2016

The Novel NF-κB Inhibitor, MTI-II Peptide Anti-Inflammatory Drug, Suppresses Inflammatory Responses in Odontoblast-Like Cells.

J Cell Biochem 2016 11 4;117(11):2552-8. Epub 2016 Apr 4.

Division of Endodontics and Restorative Dentistry, Department of Oral Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.

Regulation of inflammation is important for pulp wound healing, including protective responses by odontoblast-like cells. However, methods for directly regulating pulp inflammation have not yet been described. The inflammatory response is mediated by a transcription factor, nuclear factor-κB (NF-κB), which activates inflammatory cytokines including tumor necrosis factor (TNF)-α. Macromolecular translocation inhibitor II (MTI-II) was previously demonstrated as an enhancer of the transcriptional activity of glucocorticoid-bound glucocorticoid receptor. Recently, a MTI-II peptide anti-inflammatory drug (MPAID) was bioengineered from the structure of MTI-II as an inhibitor of NF-κB transactivation. Here, we examined the effects of MTI-II and MPAID on the inflammatory responses of odontoblast-like cells. TNF-α inhibited alkaline phosphatase (ALP) activity, a marker of odontoblast/osteogenic differentiation, and induced NF-κB transcriptional activity in KN-3 cells, which are odontoblast-like cells derived from dental papilla cells of rat incisors, without affecting their viability. Exogenous expression of MTI-II suppressed the NF-κB transcriptional activity induced by TNF-α or overexpression of p65 (a main subunit of NF-κB) in the cells, whereas it failed to inhibit degradation of IκBα and nuclear translocation of p65 after TNF-α treatment, suggesting that MTI-II inhibits NF-κB transcriptional activity by modulating the duration of DNA binding by p65. MPAID also inhibited TNF-α-induced NF-κB transcriptional activity, the mRNA expression of IL-6 and IL-8, and IL-6 production. Furthermore, pretreatment of the cells with MPAID restored the inhibitory effect of TNF-α on ALP activity. These results suggest that MPAID may be able to regulate the inflammatory response and maintain a protective response of dental pulp. J. Cell. Biochem. 117: 2552-2558, 2016. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jcb.25548DOI Listing
November 2016

Expression of Vesicular Nucleotide Transporter in Rat Odontoblasts.

Acta Histochem Cytochem 2016 Feb 10;49(1):21-8. Epub 2016 Feb 10.

Division of Orofacial Functions and Orthodontics, Kyushu Dental University.

Several theories have been proposed regarding pain transmission mechanisms in tooth. However, the exact signaling mechanism from odontoblasts to pulp nerves remains to be clarified. Recently, ATP-associated pain transmission has been reported, but it is unclear whether ATP is involved in tooth pain transmission. In the present study, we focused on the vesicular nucleotide transporter (VNUT), a transporter of ATP into vesicles, and examined whether VNUT was involved in ATP release from odontoblasts. We examined the expression of VNUT in rat pulp by RT-PCR and immunostaining. ATP release from cultured odontoblast-like cells with heat stimulation was evaluated using ATP luciferase methods. VNUT was expressed in pulp tissue, and the distribution of VNUT-immunopositive vesicles was confirmed in odontoblasts. In odontoblasts, some VNUT-immunopositive vesicles were colocalized with membrane fusion proteins. Additionally P2X3, an ATP receptor, immunopositive axons were distributed between odontoblasts. The ATP release by thermal stimulation from odontoblast-like cells was inhibited by the addition of siRNA for VNUT. These findings suggest that cytosolic ATP is transported by VNUT and that the ATP in the vesicles is then released from odontoblasts to ATP receptors on axons. ATP vesicle transport in odontoblasts seems to be a key mechanism for signal transduction from odontoblasts to axons in the pulp.
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http://dx.doi.org/10.1267/ahc.15022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4794551PMC
February 2016

Inhibition of BMP2-induced bone formation by the p65 subunit of NF-κB via an interaction with Smad4.

Mol Endocrinol 2014 Sep 16;28(9):1460-70. Epub 2014 Jul 16.

Department of Health Improvement (S.H.-T., G.S., C.N., S.K., H.T., E.J.) and Department of Oral Function (S.H.-T., T.M., C.K.), Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan; Department of Physiological Science and Molecular Biology (H.F.), Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan; Division of Pathophysiology (T.K., S.O., M.S.), Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka-shi, Saitama 350-1241, Japan; Section of Pharmacology (K.N., K.A., K.O.), Department of Bio-Matrix, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Technology and Development Team for BioSignal Program (T.D.), Subteam for BioSignal Integration, RIKEN BioResource Center, Tsukuba-shi, Ibaraki 305-0074, Japan; Laboratory of Molecular and Cellular Biochemistry (M.H.), Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; and Center for Oral Biological Research (C.K., E.J.), Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan.

Bone morphogenic proteins (BMPs) stimulate bone formation in vivo and osteoblast differentiation in vitro via a Smad signaling pathway. Recent findings revealed that the activation of nuclear factor-κB (NF-κB) inhibits BMP-induced osteoblast differentiation. Here, we show that NF-κB inhibits BMP signaling by directly targeting the Smad pathway. A selective inhibitor of the classic NF-κB pathway, BAY11-770682, enhanced BMP2-induced ectopic bone formation in vivo. In mouse embryonic fibroblasts (MEFs) prepared from mice deficient in p65, the main subunit of NF-κB, BMP2, induced osteoblastic differentiation via the Smad complex to a greater extent than that in wild-type MEFs. In p65(-/-) MEFs, the BMP2-activated Smad complex bound much more stably to the target element than that in wild-type MEFs without affecting the phosphorylation levels of Smad1/5/8. Overexpression of p65 inhibited BMP2 activity by decreasing the DNA binding of the Smad complex. The C-terminal region, including the TA2 domain, of p65 was essential for inhibiting the BMP-Smad pathway. The C-terminal TA2 domain of p65 associated with the MH1 domain of Smad4 but not Smad1. Taken together, our results suggest that p65 inhibits BMP signaling by blocking the DNA binding of the Smad complex via an interaction with Smad4. Our study also suggests that targeting the association between p65 and Smad4 may help to promote bone regeneration in the treatment of bone diseases.
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http://dx.doi.org/10.1210/me.2014-1094DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414795PMC
September 2014

Physicochemical properties of newly developed bioactive glass cement and its effects on various cells.

J Biomed Mater Res B Appl Biomater 2015 Feb 3;103(2):373-80. Epub 2014 Jun 3.

Division of Endodontics and Restorative Dentistry, Department of Science of Oral Functions, Kyushu Dental University, Japan.

Biomaterials used in dental treatments are expected to have favorable properties such as biocompatibility and an ability to induce tissue formation in dental pulp and periapical tissue, as well as sealing to block external stimuli. Bioactive glasses have been applied in bone engineering, but rarely applied in the field of dentistry. In the present study, bioactive glass cement for dental treatment was developed, and then its physicochemical properties and effects on cell responses were analyzed. To clarify the physicochemical attributes of the cement, field emission scanning electron microscopy, X-ray diffraction, and pH measurement were carried out. Cell attachment, morphology, and viability to the cement were also examined to clarify the effects of the cement on odontoblast-like cells (KN-3 cells), osteoblastic cells (MC3T3-E1 cells), human periodontal ligament stem/progenitor cells and neuro-differentiative cells (PC-12 cells). Hydroxyapatite-like precipitation was formed on the surface of the hardened cement and the pH level changed from pH10 to pH9, then stabilized in simulate body fluid. The cement had no cytotxic effects on these cells, and particulary induced process elongation of PC-12 cells. Our results suggest that the newly developed bioactive glass cement have capability of the application in dental procedures as bioactive cement.
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http://dx.doi.org/10.1002/jbm.b.33209DOI Listing
February 2015

Inhibitory effects of ameloblastin on epithelial cell proliferation.

Arch Oral Biol 2014 Aug 13;59(8):835-40. Epub 2014 May 13.

Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan.

Objective: Ameloblastin is an enamel matrix protein expressed in several tissues. Many potential mechanisms have been identified by which ameloblastin functions as an extracellular matrix protein. However, the biological effects of ameloblastin on gingival epithelial cells remain unclear. In the present study, we established a novel system to purify recombinant human ameloblastin and clarified its biological functions in epithelial cells in vitro.

Design: Recombinant human ameloblastin was isolated from COS-7 cells overexpressing HaloTag-fused human ameloblastin by the HaloTag system and then purified further by reverse-phase high-performance liquid chromatography. SCC-25 cells, derived from human oral squamous cell carcinoma, were treated with recombinant ameloblastin and then cell survival was assessed by a WST-1 assay. Cell cycle analysis was performed by flow cytometry.

Results: The novel purification system allowed effective recovery of the recombinant ameloblastin proteins at a high purity. Recombinant ameloblastin protein was found to suppress the proliferation of SCC-25 cells. Flow cytometric analysis showed that ameloblastin treatment induced cell cycle arrest G1 phase.

Conclusions: We developed a procedure for production of highly purified recombinant human ameloblastin. Biological analyses suggest that ameloblastin induces cell cycle arrest in epithelial cells and regulates the progression of periodontitis.
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http://dx.doi.org/10.1016/j.archoralbio.2014.05.010DOI Listing
August 2014

Continuous fever-range heat stress induces thermotolerance in odontoblast-lineage cells.

Arch Oral Biol 2014 Jul 18;59(7):741-8. Epub 2014 Apr 18.

Section of Operative Dentistry and Endodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan.

Objective: Heat shock during restorative procedures can trigger damage to the pulpodentin complex. While severe heat shock has toxic effects, fever-range heat stress exerts beneficial effects on several cells and tissues. In this study, we examined whether continuous fever-range heat stress (CFHS) has beneficial effects on thermotolerance in the rat clonal dental pulp cell line with odontoblastic properties, KN-3.

Methods: KN-3 cells were cultured at 41°C for various periods, and the expression level of several proteins was assessed by Western blot analysis. After pre-heat-treatment at 41°C for various periods, KN-3 cells were exposed to lethal severe heat shock (LSHS) at 49°C for 10min, and cell viability was examined using the MTS assay. Additionally, the expression level of odontoblast differentiation makers in surviving cells was examined by Western blot analysis.

Results: CFHS increased the expression levels of several heat shock proteins (HSPs) in KN-3 cells, and induced transient cell cycle arrest. KN-3 cells, not pre-heated or exposed to CFHS for 1 or 3h, died after exposure to LSHS. In contrast, KN-3 cells exposed to CFHS for 12h were transiently lower on day 1, but increased on day 3 after LSHS. The surviving cells expressed odontoblast differentiation markers, dentine sialoprotein and dentine matrix protein-1. These results suggest that CFHS for 12h improves tolerance to LSHS by inducing HSPs expression and cell cycle arrest in KN-3 cells.

Conclusions: The appropriate pretreatment with continuous fever-range heat stress can provide protection against lethal heat shock in KN-3 cells.
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http://dx.doi.org/10.1016/j.archoralbio.2014.03.014DOI Listing
July 2014

Reflection of ¹⁸F-FDG accumulation in the evaluation of the extent of periapical or periodontal inflammation.

Oral Surg Oral Med Oral Pathol Oral Radiol 2012 Dec 28;114(6):e62-9. Epub 2012 Sep 28.

Department of Oral Diagnostic Science, Kyushu Dental College, Kitakyushu, Japan.

Objectives: To elucidate whether fluorine-18-labeled ((18)F) fluoro-2-deoxy-d-glucose (FDG) accumulation can reflect the extent of periodontal inflammation, periapical inflammation, or dental caries.

Study Design: (18)F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) were retrospectively compared with the size of the bone resorption areas caused by periodontal inflammation, periapical inflammation, or dental caries on panoramic radiographs, CT, and magnetic resonance imaging (MRI) in 44 subjects.

Results: A significant correlation was found between the size of the bone resorption area caused by periodontal (r = 0.595, P < .01) or periapical (r = 0.560, P < .01) inflammation and the highest standardized uptake value (SUVmax) of (18)F-FDG accumulation. A significant correlation was found between the periodontal (r = 0.622, P < .01) or periapical (r = 0.394, P < .01) inflammatory findings on MRI and the SUVmax of (18)F-FDG accumulation. The SUVmax of (18)F-FDG around most teeth with caries was under 1.5.

Conclusions: (18)F-FDG accumulation reflects the extent of dental inflammation, not dental caries.
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http://dx.doi.org/10.1016/j.oooo.2012.05.027DOI Listing
December 2012