Polychromatic radiation is a method of measuring errors in hard tissue and is generally used for micro-CT. The study aims to estimate the age by non-destructive observation of hypercalcified dentin using monochromatic radiation x-ray micro-CT (MR-µCT) in synchrotron radiation facility (SPring 8 by RIKEN, Hyogo) eliminating the effects of beam hardening and scattered radiation. We confirmed the mineral density concordance ratio with MR-µCT and CMR. Using MR-µCT, we also investigated the relationship between hypercalcified dentin and age. The mineral density concordance rate in MR-µCT and CMR image was obtained in 44 human teeth by comparing the brightness values. The images of hypercalcified dentin were set for CMR and micro-CT after extracting from MR-µCT and the relationship between age and elapsed time years after root completion was investigated. Results showed a mineral density concordance rate of 90% or more in all samples. Hypercalcification of dentin positively correlated with age and also with elapsed time. However, the increase in values slowed down at over 40 years and after tooth eruption over 31 years. The results suggest that age estimation using hypercalcified dentin is possible through micro-CT.

Biphasic calcium phosphate (BCP) cement, consisting of an α-tricalcium phosphate-tetracalcium phosphate as the only solid phase and a calcium phosphate solution (Ca-P soln) as the liquid phase, was recently reported. The BCP cement provided sufficient handling and physical properties for clinical uses. Objective of this study was to evaluate the BCP cement when used for repairing artificially created bone defects in rat calvaria. The sample of BCP cement was prepared by mixing BCP powder with Ca-P soln at P/L of 3.0. A commercially available calcium phosphate cement, Biopex-R, was used as a positive control. Surgically created bone defects were filled with the BCP cement or the control cement. A defect with no filling material was used as a negative control. At 0 and 8 weeks after surgery, X-ray micro-CT image for each surgical site was taken. At 8 weeks after the surgery, the animals were sacrificed, and biopsies were obtained. Subsequently, the sections were subjected to HE and TRAP staining and examined under a microscope. After microscopic examination, computer-assisted histometric measurements of newly formed bone (NB) were performed using NIH image analysis. Defect closure (DC) was determined by measuring the distance between defect margin and new bone margin, and was expressed as a percentage of total defect width. The BCP cement kept original graft shape, and defects filled with the cement were mostly closed by NB. The control cement inadequately maintained original graft shape, and defects filled with the control cement were partially closed by NB. The negative control showed almost no bone formation in the defects. The DC rate of the BCP cement exhibited apparently larger than that of the control cement (p<0.05). These results were also confirmed by fluorescent labelling analysis and X-ray micro-CT observations. The results indicated that the BCP cement had osteoconductive potential for bone defects.

Maxillofacial injuries remain a serious clinical problem because of the maxilla’s anatomical significance, with important organs, including the beginning of the digestive and respiratory systems, located in this area. The purpose of this study was to assess the risk of maxillary fracture by classification of the mandibular inferior cortical shape using pantomography. This prospective study was approved by the Institutional Review Board (EC15-12-009-1). Three-hundred and sixty-four patients (190 males, 174 females; age 20 - 91 years, mean age 48.0 years) with suspected maxillary fractures who underwent both pantomography and multidetector row computed tomography (MDCT) from April 2011 to December 2016 were included in this study. The mandibular inferior cortical shape was evaluated by pantomography on both sides of the mandible, distal to the mental foramen by specialist of two oral and maxillofacial radiologists, and classified into three types as follows; Type l: normal cortex, Type 2: mildly to moderately eroded cortex and Type 3: severely eroded cortex. Moreover, the patients were divided into two groups; Group I: normal bone mineral density (Type 1) and Group II: low bone mineral density (Types 2 and 3). The presence of maxillary fractures and the classification of the mandibular inferior cortical shape were compared using pantomography. Of the 364 patients, fractures were seen in 219 patients (60.2%). Of the 219 patients with maxillary fractures, 51 patients were in Group I (23.3%) and 168 patients were in Group II (76.7%). Of the 145 patients without maxillary fractures, 120 patients were in Group I (82.8%) and 25 patients were in Group II (17.2%). There was a statistically significant difference between Groups I and II in the prevalence of maxillary fractures (p<0.05). Our results suggest that classification of the mandibular inferior cortical shape using pantomography may provide a risk assessment for maxillary fracture.

Laser irradiation is using to treat oral peri-implantitis instead of surgical curettage to removing bacteria and inflammatory granulation material adhered to the implant surface. However, there were few effects known about laser treatment for periodontal cell functions. Therefore, in this study, we investigated the effect of CO₂ laser irradiation on titanium surface and human periodontal ligament fibroblasts (HPdLF) with or without lipopolysaccharide (LPS) treatment. HPdLF cells were cultured on polished and roughed titanium plates, with or without LPS. CO₂ laser irradiated to the each culture of titanium surface. HPdLF proliferation, type I collagen, vascular endothelial growth factor (VEGF), and actin formation were evaluated. Actin was detected by phalloidin staining. Gene expression changes of type I collagen and VEGF in HPdLF were also analyzed by RT-PCR. CO₂ laser irradiation did not changes on both titanium surface. HPdLF proliferation was suppressed until the culture day 7 by LPS addition on both surfaces. However, HPdLF adhesion and proliferation increased after CO₂ laser irradiation on both titanium surfaces regardless of LPS treatment. Also, Type I collagen and VEGF productions of HPdLF increased after CO₂ laser irradiation on both titanium surfaces with or without LPS treatment. CO₂ laser irradiation of the titanium surface promoted growth and differentiation of HPdLF under LPS conditions, suggesting that induction of collagen production and angiogenesis for tissue regeneration can occur on irradiation-treated implant surfaces.

It is well-known that mesenchymal stem cells responsible for periodontal tissue regeneration exist in the periodontal ligament by differentiation into fibroblasts, cementoblasts, and osteoblasts. However, the detailed characteristics of stem cells have not been clarified. Recently, the presence of a novel stem cell called Muse cells has been reported. It was mentioned that Muse cells exist in all mesenchymal tissues, and which can be found in the bone marrow, skin and adipose tissues. Nevertheless, the existence of Muse cells in oral tissues has not yet been reported. This study investigated whether Muse cells are present in the periodontal ligament. Results showed that about 0.83% of Muse cells sorted out from periodontal ligament cells showed the ability for self-renewal as well as the expression of genes present in all three germ layers. When compared to Muse cells derived from the skin for calcification ability, Muse cells derived from periodontal ligament showed higher calcification ability both at gene and tissue levels. Although both cells were considered Muse cells, cells derived from the periodontal ligament have different characteristics compared to the Muse cells derived from the skin. The results suggest that stem cells derived from somatic cells are possible to maintaining the original phenotypes. Therefore, when using stem cells for regenerative medicine, we suggest that the stem cells should be sorted from the same tissue, which expects repair or regeneration of the tissue.

Carbon nanotubes have been explored as heat-delivery vehicles for thermal ablation of tumors. To use single-walled carbon nanotubes (SWNT) as a “molecular heater” for hyperthermic therapy in cancer treatment, stable dispersibility and smart-targeting potential are necessary. The current study reports the dispersibility and exothermic properties with near-infrared (NIR) exposure for SWNT coated with a copolymer of N-isopropylacrylamide and polyethyleneglycol methacrylate (SWNT/PNIPAM-PEG-hybrid). The SWNT/PNIPAM-PEG hybrid showed stable dispersibility in PBS solution and exothermic potential with NIR exposure. Raman spectroscopy results revealed a hybrid-derived Raman peak in mouse liver and spleen lysates for 7 days post-injection that disappeared by 14 days in all tissues (liver, spleen, heart, lung and kidney). These results suggested that the hybrid did not accumulate in mouse organ tissues in the long-term. The SWNT/PNIPAM-PEG hybrid decreased the cell viability (of mouse macrophages) with heat generation by NIR exposure. The results of this study demonstrate that the SWNT/PNIPAM-PEG hybrid is a useful platform for a “molecular heater” applicable to hyperthermic cancer therapy.

Nano-apatite could be prepared from a homogeneous solution of calcium (Ca)-aspartic acid (Asp) and Ca-glutamic acid (Glu) chelate complex with a high yield. Asp and Glu are components of non-collagenous proteins. Arginine is used to adjust pH to obtain precipitation from a Ca complex solution. Apatite from a Ca- ethylenediaminetetraacetic acid (EDTA) chelate complex was also prepared. These apatites are referred to as Asp-HA, Glu-HA, and EDTA-HA, respectively. Nano-apatite paste was obtained after mixing with water. Synthesized nano-apatite was characterized by X-ray diffraction and Fourier transform infrared measurements. It was revealed that Asp-HA and Glu-HA showed smaller crystal sizes with nano-scale, higher lattice distortion and greater degree of consistency as compared to EDTA-HA. The elution of Ca ion forms Asp-HA and Glu-HA were smaller than that of EDTA-HA. To investigate the influence of the different amino acid ligands for calcium on bone response, bone responses to each nano-apatite paste were evaluated after transplantation into the subperiosteal pocket of the rat calvarial skeleton. Asp-HA and Glu-HA showed greater amounts of new bone formation than EDTA-HA. New bone formation progressed at an especially early stage after implantation with Asp-HA. It is suggested that Asp-HA paste will be useful for bone regeneration.

Structural maintenance of chromosomes 4 (SMC4), a member of SMC protein family, was overexpressed in numerous human epithelial tumors, such as colorectal cancer, hepatocellular carcinoma and so on, suggesting an significant promotion role in tumor progression. However, the expression pattern and potential role of SMC4 in salivary gland tumors (SGTs) were not clear. The aim of this study was to detect the expression pattern of SMC4 in normal salivary glands and three SGTs in order to discuss the role of SMC4 and find a new therapeutic target. SMC4 expression patterns were examined immunohistochemically in 20 normal salivary glands and 94 SGTs. In normal salivary glands, SMC4 strongly expressed in cytoplasm of ductal epithelial cells, and hardly expressed in the abluminal (myoepithelial) cells and luminal (epithelial) cells of seromucous acini. In salivary adenoid cystic carcinoma (SACC), we detected that SMC4 showed positive expression on cytoplasm and no significant difference among tubular, cribriform and solid SACC tissues (5/15; 33.3%, 5/15; 33.3%, 8/20; 40%). SMC4 was negative or weakly expressed in cytoplasm of pleomorphic adenoma (PA) (2/26; 7.7%). The positive rate of SMC4 was 20% (1/5) in well-differentiated mucoepidermoid carcinoma (MEC) and up to 84.6% (11/13) of strong cytoplasmic and nuclear SMC4 expression in poor-differentiated MEC. The sites of SMC4 expressions in MEC tissues were intermediate cells and epidermoid cells. These findings confirmed that SMC4 was negative in benign SGT, but strongly expressed in malignant SGTs especially in MECs. SMC4 may play a key role in poor-differentiated MECs and a specific biomarker for the degree of MEC malignancy.

The aim of this in vitro study was to compare the effect of different protective agents on the surface microhardness and morphology on enamel eroded by a cola drink. Sixty sound anterior teeth were randomly divided into five groups. The baseline surface microhardness of the enamel was measured. For demineralization procedures, all teeth were immersed in cola for 8 minutes and surface microhardness was remeasured. The five groups for remineralization procedures were defined as: Group 1: Artificial saliva, Group 2: 1.23% Acidulated Phosphate Fluoride gel (APF), Group 3: 5% NaF varnish, Group 4: Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP), and Group 5: Probiotic yogurt. After each experimental procedure, a third microhardness measurement was repeated. Surface morphological changes were observed using SEM. All data were recorded for each group and statistically analyzed using two-way analysis of variance and one-way repeated-measures analysis of variance. All tests were performed at a significance level of p < 0.05. No significant differences for baseline microhardness values were found (P> 0.05). The mean surface microhardness in all groups decreased significantly after immersion in cola (P< 0.05). After remineralization, NaF varnish and APF gel significantly increased the surface microhardness values. There were no significant increases in the surface microhardness values of artificial saliva, CPP-ACP and probiotic yogurt. This study concludes that NaF varnish is more effective in re-hardening of eroded enamel.

The aim of the study was to investigate the clinical results and safety of oral propranolol combined with topical timolol maleate for the management of infantile hemangioma in parotid region. Between October 2014 and June 2017, 25 infants with parotid hemangiomas were treated with a combination of oral propranolol and topical timolol maleate. There were 10 males and 15 females, aged from 2 to 10 months with a mean age of 4.5 months. Propranolol was administrated at a dose of 1.0-1.5 mg/kg body weight, and the drug was taken once per day. All lesions were also administrated using topically timolol maleate in every 12 hours. The blood pressure, heart rate values, and adverse events were recorded during hospitalization. The electrocardiogram was reviewed one month after discharge. The therapeutic outcomes and safety were assessed by the changes of color, size of tumor, and adverse effects throughout the course of treatment. The mean therapy duration was 5.6 months ranged from 3 to 10 months. Of 25 the patients, 17 demonstrated excellent response, 8 showed good response. The heart rate, systolic blood pressure and diastolic blood pressure were all decreased to some extent in the children after administration, but the difference was not statistically significant (all P > 0.05), and also was not associated with any clinical symptoms. No serious adverse effects were encountered. Oral propranolol combined with topical timolol maleate was an effective treatment for infantile parotid hemangioma with minor side effects, and might be used as the first-line treatment selection.