In order to evaluate the biocompatibility and mineral repair capacity, mineral trioxide aggregate (MTA), portland cement normal setting (PCn) and fast setting (PCf) and calcium hydroxide-based paste (Calen) filled silicone tube were implanted into the dorsal subcutaneous connective tissues of 25 Wistar rats. Animals were euthanized at 24, 72 hours, 7, 15 and 30 days. Implants with surrounding tissues were fixed with 10% buffer formaldehyde and processed for histological routine techniques. Slides (5 µm serial cuts) were stained with H&E and Von Kossa stains for morphological, qualitative and quantitative analysis by light microscopy. Calen showed severe and moderate inflammatory response and granulomatous reaction with psammoma body-like formation. PCn and MTA have similar behavior, with mild inflammatory reaction from 8% and 4%, respectively. Even though, PCn and MTA demonstrated analogous biological reaction, MTA developing thick artificial mineral precipitation (p = 0,007). All sealers demonstrated a similar inflammatory response at all time periods studied (p = 0.678).
To clarify the chemical processes of dental caries in detail, and to clarify whether or not the caries processes are common through the whole part of various teeth, the micro-FTIR spectroscopic analysis was carried out using the human teeth sections soaking into a carbonated soft drink (Sprite®) for 1 and 7 days. After the twenty human teeth examined, the teeth were grouped into two; the lightly dissolved one and extremely heavily dissolved one on the basis of the macroscopical and microscopical features after the soaking experiment. In this study, one lightly dissolved sample (A) and one heavily dissolved sample (B) were picked up and described. The micro-FTIR spectroscopy showed the drastic changes in the P-O absorption bands of the outer layer enamel of both samples, while those of the inner layer enamel remained almost unalterably. This result indicated that the erosive processes mainly attacked the phosphate ion environments in the biological apatite crystal structure of tooth enamel. The second order differential curves of the micro-FTIR patterns firstly reported here showed the small but significant P-O band peak shifts among the all analyzing points except for 7 days of Sample B, suggesting the individual physicochemical characteristic of tooth enamel apatite. This study presented only two extreme cases, but clearly showed the variety of human tooth enamel characteristics among the individuals and parts of the tooth enamel. It was suggested that generally accepted caries protection methods might not be a common standard for every people and every teeth enamels.
Although titanium material is currently widely used in dental and orthopedic application, the bio-inertness of Ti impairs its further use. We previously reported the good bioactivity and biocompatibility of TiO2 nanotube layer fabricated by anodic oxidation technique using in vitro tests. In the present work, we further clarify the cell adhesion and osseointegration properties of anodized surface through both in vitro and in vivo tests. After anodic oxidation (AO), the structure of nanotubes was confirmed by scanning electron microscopy. The surface roughness and hydrophilic properties of the AO and pristine Ti surfaces were evaluated by atomic force microscopy and contact angle measurement test, respectively. It was found that the AO surface displayed moderately higher surface roughness and obviously increased wettability, compared to the original Ti surface. In vitro cellular activity tests demonstrated that osteoblast cells cultured on the AO surface exhibited a much well-spread cytoskeleton organization with more stretched actin filaments, compared to those cultured on the Ti surface. The adherent cell number was also higher on the AO surface than the pure Ti substrate. In addition, we explore the molecular basis of mechanism by analyzing gene expression levels of adhesion and osteogenesis-related genes in MC3T3-E1 cells cultured on different surfaces using quantitative real-time PCR. Increased mRNA levels of vinculin, collagen type 1, osteopontin and osteocalcin were found on the AO surface, compared with the control group. Furthermore, in vivo animal experiment using a rat model revealed that anodized implant surface promotes osseointegration and demonstrated higher bone bonding strength compared to the pure Ti substrate. Our study revealed the superior cell adhesion property, increased adherent and osteogenesis-related gene expressions and enhanced osseointegration by anodized surface, thus implying its enlarged application in future.
The nature of crime is changing day by day and the forensic scientists are always facing new problems in human identification. The practice of destroying human body by immersing in an acid is drawing a great deal of forensic interest these days. The present study aimed to identify the acid that is most likely used in such crimes and to determine if the morphological changes in teeth and different restorative materials could predict the approximate duration of time elapsed after immersion of a body in an acid. 240 teeth with and without different restorations were immersed separately in 3 different acids and were observed for morphological changes over a period of 30 days. Teeth dissolved completely in hydrochloric acid (HCl) and nitric acid (HNO3) by 48 hrs and 20 hrs respectively. Teeth showed precipitation in sulphuric acid (H2SO4) with only remnants of white precipitate by the end of 288 hrs. Amalgam restorations in HCl did not show any changes. They exhibited blackish discoloration on the surface when placed in H2SO4, but in HNO3, they settled as silver powder with the release of brown fumes. Composite restorations in HCl and HNO3 did not demonstrate considerable morphological changes. In H2SO4, they showed surface discoloration and softening. Glass ionomer cement (GIC) in HCl and HNO3 dissolved completely. In H2SO4 they settled as white precipitate. When a human body is destroyed using acids, teeth or restorative materials retrieved can serve as an effective tool in crime investigations and can help the investigator to deduce the time elapsed since the commitment of crime.
Objective: This study aims to analyse the cellular compatibility of the membrane made of poly (propylene carbonate) (PPC) and nanohydroxyapatite (nHAp) by solvent casting/particulate leaching. Experimental Methods: Observating the surface characters of different compositions nHAp/PPC membrane (0 wt%, 10 wt%, 20 wt%, 30 wt%, and 40 wt% nHAp), and evaluating its compatibility with MG63 cells. Results: Scanning electron microscopy showed that with the increased nHAp content, the roughness of the membrane surface increased. The results from our in vitro studies indicated that the MG63 cells cultured with nHAp/PPC membrane did not appear to have cytotoxic responses, and the nHAp/PPC membrane could improve the proliferation of MG63 cells when compared to controls (p < 0.05). Additionally, the cell activity, total protein, and alkaline phosphatase increased with the increased nHAp content.
Macrophages are involved at an early stage of the inflammatory reaction and have an important role in wound healing. Granulocyte-macrophage colony stimulating factor (GM-CSF) stimulates the proliferation and differentiation of macrophages. We investigated the secretion of tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4) from mouse macrophages (RAW264.7) activated by GM-CSF. RAW264.7 cells were cultured on titanium (Ti) discs. Secretion of TNF-α and IL-4 was evaluated using enzyme-linked immunosorbent assay (ELISA) at 24 h and 48 h. Cell morphologies were observed using SEM, and cell viability was accessed by an MTT assay.
GM-CSF caused rough and irregular surface morphology on the macrophages and resulted in a significant difference in cell viability after 48 h (p<0.05). TNF- α secretion significantly decreased after 48 h without GM-CSF compared with that at 24 h (p<0.05). GM-CSF significantly increased the secretion of TNF-α after 24 h and 48 h (p<0.05). IL-4 secretion was significantly different with or without GM-CSF stimulation at 24 h and 48 h (p<0.05). There was a significant increase in IL-4 secretion 24 h and 48 h after GM-CSF stimulation (p<0.05).
These results suggest that macrophage stimulated GM-CSF may promote secretion of anti-inflammatory and pro-inflammatory cytokines on Ti.
To clarify the phenotypic changes of basal cells of oral squamous epithelium during pathological regeneration, 40 cases diagnosed as mucous cyst and 10 cases including normal epithelium were used as experimental and control subjects. Antibodies against desmoglein 1 (DSG1), desmocollin 3 (DSC3), keratin 19 (K19) and Ki-67 nuclear antigen (Ki-67) were used for immunohistochemical examinations. Ki-67 index values and the combinations of DSG1, DSC3 and K19 reactivity were analyzed using hierarchical clustering and one-way ANOVA. In contrast to the controls, experimental specimens showed DSG1 positive, DSC3 negative and K19 negative, in 50%, 10% and 87.5% of the experiments, respectively. Cluster hierarchy analysis divided all samples including controls and experiments into three clusters mostly demonstrating DSG1+/DSC3+/K19-, DSG1-/DSC3+/K19+ and DSG1-/DSC3+/K19- as clusters 1, 2 and 3, respectively. Cluster 1 showed significantly higher values of Ki-67 than did cluster 3. The value of DSG1 positive was statistically significant compared with that of DSG1 negative. Our results show that the alteration from DSG1 negative to DSG1 positive could be crucial for cell proliferation, accompanied by K19-loss, which is consistent with the effects of regulatory molecules such as SIRT2 or EphA2 following EGFR-upregulation. We have to be aware that the loss of basal cell character with DSG1 and K19 alterations are basic phenomena in pathological regeneration, and abnormal DSC3-loss infrequently occurs in non-neoplastic conditions.
Osteoarthritis (OA) is a degenerative joint disease which is one of the most frequent and disabling diseases encountered in elderly individuals. Leptin was unregulated significantly in OA cartilage and was regarded as a metabolic link between obesity and OA. In this study, we evaluated the effect of 10 or 100 ng/ml leptin on the ATDC5 cells. Results revealed that 10 or 100 ng/ml of leptin significantly decrease the expression of aggrecan and type II collagen mRNA and protein levels compare to control (0 ng/ml). Interestingly, sex determining region Y-box 9 mRNA and protein was down-regulated by leptin. Collagen X is a specific marker of hypertrophic and calcified chondrocyte. It has been noted that both mRNA and protein of Collagen X was significantly upregulated with leptin treatment. Meanwhile, Alcian Blue staining indicated that leptin reduces the synthesis of proteoglycan. Alizarin red S staining and alkaline phosphatase activity detection demonstrated that leptin induced cartilage nodules formation and mineralization in a dose dependent manner. We conclude that leptin slightly inhibits the proliferation of ATDC5 cells and affects cartilage-specifically marked proteins and genes. In summary, it has been suggested that leptin stimulate hypertrophic differentiation of ATDC5 cells.
The study was to observe dental implant osseointegration at early stage and analysis the influencement of the ratio of calcium and phosphorus variation on osseointegration in hyperlipidemic rats. Wistar rats were randomly divided into control group with normal diet and experimental group with high fat diet. 8 weeks later, serum lipid levels was detected and titanium implants were placed into bilateral femurs. At day1, 3, 5 after implant, rats were sacrificed and 5 mm bone with implants was obtained. hard tissue slices and methylene blue-acid fuchsin staining were performed to observe the interface of bone-implant. And energy disperse X-ray spectrometer (EDS) was used to measure the percentage of oxygen and the ratio of calcium and phosphorus. All rats in experimental group were successfully induced into hyperlipidemic status. Histological results revealed less osteoblasts and trabecular bone, but more osteoclasts and trabecular space in experimental group than those in control group. Higher content of oxygen and lower ration of calcium and phosphorus were also observed in experimental group than those in control group (P<0.05). Hyperlipidemia could hinder implant osseointegration at early stage after implantation. This inhibition might be closely related to higher content of oxygen and lower ratio of calcium and phosphorus.
This study aimed to investigate the role of autophagic stages through the interplay of AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Beclin-1 signaling pathways in osteogenic differentiation of human periodontal ligament stem cells (HPLSCs) using a combination of pharmacological inhibition and genetic knockdown approaches. The activation or inactivation of these factors and autophagy was evaluated by western blot and immunocytochemical assays, while osteogenic differentiation was analyzed by alkaline phosphatase staining. Enhancement of osteogenic differentiation of HPLSCs was correlated with the increased expression of the autophagy markers Beclin-1 and microtubule-associated protein 1 light chain 3-II (LC3-II), and phosphorylation of AMPK, consistent with reduced expression of phosphorylated p70S6 kinase, mTOR substrate. The RNA interference-mediated silencing of AMPK and Beclin-1 (marker of early autophagy) and the pharmacological inhibitors of AMPK (compound C) and early autophagy (3-methyladenine) suppressed acceleration of osteogenic differentiation and autophagy. mTOR inhibition increased both osteogenic differentiation and autophagy. Inhibition of the late stage of autophagy by LC3 siRNA and chloroquine resulted in no changes in the osteogenic differentiation of HPLSCs. These findings suggest that the early stages of autophagy through the AMPK/mTOR/Beclin-1 signaling pathway may be required for the enhancement of osteogenic differentiation of HPLSCs.
Efforts to improve the bone-implant interface to accelerate and improve the quality of osseointegration have generally focused on chemically improving the interface by incorporating inorganic phases on or into the titanium oxide layer or physically improving it by increasing the level of roughness. However, some types of rough-surfaced implants, such as those coated with hydroxyapatite (HA), may result in a higher incidence of complications. Once peri-implantitis occurs, the factors promoting bone integration can turn into risk factors, exacerbating inflammation around the implant fixture. Thus, it is extremely important to study approaches for accelerating bone formation around the machined surface dental implants. Peri-implant bone formation may be enhanced by systemic approaches, such as the use of osteoporosis supplements, to promote bone metabolism. The present study aimed to investigate if peri-implant bone mineral density (BMD) was improved after oral synthetic bone mineral (SBM) intake, which facilitates improved secondary stability of the machined surface dental implants and shortens the healing period. Twenty-four 7-week-old female Wistar rats were randomly assigned to receive a standardized diet with or without SBM (diet with SBM group and diet without SBM group, respectively; n = 12 for both). The rats underwent implant surgery at 9 weeks of age under general anesthesia. The main outcome measures BMD, pull-out strength, real-time PCR and Fluorescence microscopy observations of the implant from the femur were compared at 2 and 4 weeks after implantation using the Mann-Whitney U test. At 2 and 4 weeks after implantation, BMD, pull-out strength, real-time PCR and fluorescence microscopy observations were both significantly greater in the diet with SBM group than in the diet without SBM group. This study demonstrated that SBM could be effective in accelerating peri-implant bone formation for machined surface implants during the healing period after implantation.
Pneumomediastinum and/or cervicofacial subcutaneous emphysema are extremely rare but severe complications in third molar surgery. The most common cause is compressed air exhaust from an air-driven high-speed handpiece. To prevent these complications, treatment with an electric handpiece that does not use the drive air is generally recommended; however, its safety has not been fully verified. In this study, we investigated electric handpiece-related emphysema during third molar surgery. We evaluated patients who visited our hospital in relation to third molar surgery between January 2008 and December 2017. Of the 2938 patients examined, 2 patients were complicated with electric handpiece-related pneumomediastinum and cervicofacial subcutaneous emphysema during sectioning the mandibular third molar. In these cases, a straight motor handpiece and a 1:5 speed increasing contra-angle motor handpiece were used, respectively. Both patients received antibiotics and follow-up examination under hospitalization. Although the air flow and pressure of an electric handpiece are lower than those for air-driven high-speed handpieces, the air expelled from electric handpieces could cause cervicofacial emphysema and/or pneumomediastinum. It should be noted that electric handpieces do not use the drive air; however, most of these handpieces have air/water nozzles and use tip air. Before treatment, an informed consent to patients about the risk of emphysema is mandatory. With regard to the surgical technique, elevation of the mucoperiosteal flap should be minimal. Attention should be also paid to the possibility that the air inflow route is made through removal or perforation of the cortical bone. To prevent emphysema, an electric surgical handpiece with an external water spray may be preferable for removing the bone and cutting the tooth, because this type of surgical handpiece has a separate water drip for cooling instead of combined water and air spray, and it does not use the flux of air.
This study investigated the gender disparity, side disparity and relationship of mandible size to mandibular canal location using CBCT scans in a Saudi Arabian subpopulation. 856 CBCT scans of Saudi Arabian subpopulation were selected from the radiology archive. Linear measurements were calculated from horizontal lines drawn from the inferior border of the mandibular canal (D1), the distance from superior border of the mandibular canal to the apical root apex of the mesial root of the mandibular 2nd molar (D2), the distance from the alveolar crest in between mandibular 1st and 2nd molar to superior border of the mandibular canal (D3), the distance, from the superior border of the mandibular canal to apical root apex of the mandibular 2nd premolar (D4), height of the mandibular canal under the mandibular 1st molar (D5) and the distance from inferior border of the mandibular canal in between mandibular 1st and 2nd molar to inferior border of mandible (D6). Mandible size was calculated and grouped as Group I- Average mandible (D7 length ranging from 72.5 (±2 SD) Group II- Large mandible (D7>74.5) Group III- Small mandible (D7<70.5). The mean difference of measured variables in gender comparison and side disparity was statistically insignificant (p<0.05). No severe asymmetry was revealed. There was no statistically significant difference between the mandible size groups. The mandibular canal in Saudi Arabian subpopulation has no gender disparities, almost symmetrical position with no side disparity and location of mandibular canal is independent of mandible size.
The panoramic radiography taken for the dental treatment sometimes shows carotid artery calcification and it is known that the carotid artery calcification is associated with the onset of vascular disorder. In this regard, this study focused on the right/left difference in the carotid artery calcification showed by panoramic radiography and CT. The subjects of this study were 119 patients in the 5th to the 10th decade whose carotid artery calcification was confirmed by panoramic radiography and CT from August 2004 to June 2018 at Matsumoto Dental University Hospital. We investigated whether carotid artery calcification between the third and fourth cervical vertebrae can be detected using panoramic imaging. At the same time, the presence or absence of calcification image around the third and fourth cervical vertebrae was also investigated on the basis of axial CT image. The results indicated the following. As to the gender difference, the males demonstrated a slightly higher ratio of calcification in comparison with the females (10:9). As to the age distribution, a tendency of increase in calcification was noted in the 7th decade and over and the ratio was the highest in the 8th decade (42 cases). As to the right/left difference in the 119 patients, there were 67 patients with bilateral calcification and 52 patients with unilateral calcification (24 on the left side and 28 on the right side), indicating hardly any right/left difference. Regarding to the right/left prevalence, in the 7th decade and over had bilateral calcification accounted for 50% and over. On the other hand, calcification was more frequently observed on the right side in the 6th decade in the males as well as in the females. These results suggest that there is the different of unilateral (right/left difference) or bilateral carotid artery calcification by generation.