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Chiang YC, Lin HP, Chang HH, Cheng YW, Tang HY, Yen WC, Lin PY, Chang KW, Lin CP. A mesoporous silica biomaterial for dental biomimetic crystallization. ACS NANO 2014; 8:12502-12513. [PMID: 25482513 DOI: 10.1021/nn5053487] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The loss of overlying enamel or cementum exposes dentinal tubules and increases the risk of several dental diseases, such as dentin hypersensitivity (causing sharp pain and anxiety), caries, and pulp inflammation. This paper presents a fast-reacting, more reliable and biocompatible biomaterial that effectively occludes exposed dentinal tubules by forming a biomimetic crystalline dentin barrier. To generate this biomaterial, a gelatin-templated mesoporous silica biomaterial (CaCO3@mesoporous silica, CCMS) containing nanosized calcium carbonate particles is mixed with 30% H3PO4 at a 1/1 molar ratio of Ca/P (denoted as CCMS-HP), which enables Ca2+ and PO4(3-)/HPO4(2-) ions to permeate the dentinal tubules and form dicalcium phosphate dihydrate (DCPD), tricalcium phosphate (TCP) or hydroxyapatite (HAp) crystals at a depth of approximately 40 μm (sub-μ-CT and nano-SEM/EDS examinations). In vitro biocompatibility tests (WST-1 and lactate dehydrogenase) and ALP assays show high cell viability and mineralization ability in a transwell dentin disc model treated with CCMS-HP (p<0.05). The in vivo efficacy and biocompatibility analyses of the biomaterial in an animal model reveal significant crystal growth (DCPD, TCP or HAp-like) and no pulp irritation after 70 days (p<0.05). The developed CCMS-HP holds great promise for treating exposed dentin by growing biomimetic crystals within dentinal tubules. These findings demonstrate that the mesoporous silica biomaterials presented here have great potential for serving as both a catalyst and carrier in the repair or regeneration of dental hard tissue.
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Lee MS, Chen YL, Huang PH, Chiang YC, Chang HH, Wu J, Lin CP. Effects of ultrasonic and high-speed air-driven devices on pulp–dentin reactions: An animal study. J Dent Sci 2014. [DOI: 10.1016/j.jds.2013.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Cher TL, Lin CP, Huang CS. Clinical dental care in hospital dental departments in Taiwan: Results from the 2008 national survey. J Dent Sci 2014. [DOI: 10.1016/j.jds.2013.02.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Chang CC, Chang KC, Tsai SJ, Chang HH, Lin CP. Neurogenic differentiation of dental pulp stem cells to neuron-like cells in dopaminergic and motor neuronal inductive media. J Formos Med Assoc 2014; 113:956-65. [PMID: 25438878 DOI: 10.1016/j.jfma.2014.09.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 08/20/2014] [Accepted: 09/03/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND/PURPOSE Dental pulp stem cells (DPSCs) have been proposed as a promising source of stem cells in nerve regeneration due to their close embryonic origin and ease of harvest. The aim of this study was to evaluate the efficacy of dopaminergic and motor neuronal inductive media on transdifferentiation of human DPSCs (hDPSCs) into neuron-like cells. METHODS Isolation, cultivation, and identification of hDPSCs were performed with morphological analyses and flow cytometry. The proliferation potential of DPSCs was evaluated with an XTT [(2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide)] assay. Media for the induction of dopaminergic and spinal motor neuronal differentiation were prepared. The efficacy of neural induction was evaluated by detecting the expression of neuron cell-specific cell markers in DPSCs by immunocytochemistry and quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). RESULTS In the XTT assay, there was a 2.6- or 2-fold decrease in DPSCs cultured in dopaminergic or motor neuronal inductive media, respectively. The proportions of βIII-tubulin (βIII-tub), glial fibrillary acidic protein (GFAP), and oligodendrocyte (O1)-positive cells were significantly higher in DPSCs cultured in both neuronal inductive media compared with those cultured in control media. Furthermore, hDPSC-derived dopaminergic and spinal motor neuron cells after induction expressed a higher density of neuron cell markers than those before induction. CONCLUSION These findings suggest that in response to the neuronal inductive stimuli, a greater proportion of DPSCs stop proliferation and acquire a phenotype resembling mature neurons. Such neural crest-derived adult DPSCs may provide an alternative stem cell source for therapy-based treatments of neuronal disorders and injury.
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Chang KC, Chang CC, Chen WT, Hsu CK, Lin FH, Lin CP. Development of calcium phosphate/sulfate biphasic cement for vital pulp therapy. Dent Mater 2014; 30:e362-70. [PMID: 25189109 DOI: 10.1016/j.dental.2014.08.368] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 07/28/2014] [Accepted: 08/08/2014] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Bioactive calcium phosphate cement (CPC) has been used widely to repair bone defects because of its excellent biocompatibility and bioactivity. However, the poor handling properties, low initial mechanical strength, and long setting time of CPC limit its application in vital pulp therapy (VPT). The aim of this study was to synthesize biphasic calcium phosphate/sulfate cements and evaluate the feasibility of applying these cements in VPT. METHODS The physical, chemical, and mechanical properties of CPC were improved by mixing the cement with various amounts of α-calcium sulfate hemihydrate (CSH). The hydration products and crystalline phases of the materials were characterized using scanning electron microscopy and X-ray diffraction analysis. In addition, the physical properties, such as the setting time, compressive strength, viscosity, and pH were determined. Water-soluble tetrazolium salt-1 and lactase dehydrogenase were used to evaluate cell viability and cytotoxicity. RESULTS The developed CPC (CPC/CSH cement), which contains 50wt% CSH cement, exhibited no obvious temperature increase or pH change during setting when it was used as a paste. The initial setting time of the CPC/CSH biphasic cement was substantially shorter than that of CPC, and the initial mechanical strength was 23.7±5.6MPa. The CPC/CSH cement exhibited higher viscosity than CPC and, thus, featured acceptable handling properties. X-ray diffraction analysis revealed that the relative peak intensity for hydroxyapatite increased, and the intensity for calcium sulfate dehydrate decreased as the amount of CPC was increased. The cell viability and cytotoxicity test results indicated that the CPC/CSH cement did not harm dental pulp cells. SIGNIFICANCE The developed CPC/CSH biphasic cement exhibits substantial potential for application in VPT.
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Cheng YA, Huang SH, Hsien HC, Chiang YC, Lin CP. Influence of cyclic heating on physical property and biocompatibility of α- and β-form gutta-percha. J Formos Med Assoc 2014; 113:498-505. [PMID: 25037756 DOI: 10.1016/j.jfma.2012.07.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND/PURPOSE Thermoplasticized techniques with high temperature and repetitive heating in root canal filling may cause degeneration of gutta-percha, producing cytotoxic byproducts and interfering sealing quality. This study was conducted to investigate the influence of cyclic heating on the physical property and biocompatibility of α- and β-form gutta-perchas. METHODS Both α- and β-form gutta-perchas were submitted to two heating processes: continuous heating and cyclic heating. Continuous heating was carried out by heating the samples up to 300°C and 400°C. The samples were then analyzed by differential scanning calorimetry, differential thermal analysis (DTA), and thermogravimetry. For cyclic heating process, samples were heated from 30°C to 200°C for seven cycles and analyzed with DTA and thermogravimetry. For cell adhesion assay, samples were treated (30°C to 200°C, one and seven cycles), submitted to cell culture and examined by scanning electron microscope. RESULTS Differential scanning calorimetry and DTA indicated that α-form gutta-percha presented a major endothermic peak at 50-57°C, while β-form gutta-percha showed two major endothermic peaks at 46-50°C and 60-63°C. Total weight loss of β-form gutta-percha was about 2-fold greater than that of α-form gutta-percha after continuous heating up to 300°C, or cyclic heating for seven times. Scanning electron microscopy showed no obvious difference of cell adhesion on α- and β-form samples, even with seven cyclic heating or one heating cycle. However, the attachment of the cells to the culture plate (the control) is better than to the gutta-percha samples. CONCLUSION The increase of heating cycles for α- and β-form gutta-percha exerts no adverse influence on their biocompatibility. Because the physical property of β-form gutta-percha becomes unstable when it is heated at over 300°C or subjected to cyclic heating, β-form gutta-percha may not be recommended for use in thermoplasticized gutta-percha techniques.
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Wang YL, Chang CC, Chi CW, Chang HH, Chiang YC, Chuang YC, Chang HH, Huang GF, Liao YS, Lin CP. Erosive potential of soft drinks on human enamel: an in vitro study. J Formos Med Assoc 2014; 113:850-6. [PMID: 25001324 DOI: 10.1016/j.jfma.2014.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 05/30/2014] [Accepted: 06/03/2014] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND/PURPOSE Most soft drinks are acidic in nature. Regular consumption of these drinks may result in dental erosion. The aim of this in vitro study was to evaluate the erosive potential of different soft drinks in Taiwan by a novel multiple erosive method. METHODS Four commercially available soft drinks in Taiwan were selected for this study. The properties of each product were analyzed to measure their pH, titratable acidity, and ion contents. The erosive potential of the soft drinks was measured based on the amount of loss of human enamel surface following its exposure to the soft drinks tested for different periods (20 minutes, 60 minutes, and 180 minutes). The enamel loss was measured using a confocal laser scanning microscope. RESULTS The pH values of the soft drinks were below the critical pH value (5.5) for enamel demineralization, and ranged from 2.42 to 3.46. The drink with ingredients of citric acid and ascorbic acid had the highest titratable acidity (33.96 mmol OH(-)/L to pH 5.5 and 71.9 mmol OH(-)/L to pH 7). Exposure to all the soft drinks resulted in loss of human enamel surface (7.28-34.07 μm for 180-minute exposure). The beverage with the highest calcium content had the lowest erosive potential. CONCLUSION All tested soft drinks were found to be erosive. Soft drinks with high calcium contents have significantly lower erosive potential. Low pH value and high citrate content may cause more surface enamel loss. As the erosive time increased, the titratable acidity to pH 7 may be a predictor of the erosive potential for acidic soft drinks. The erosive potential of the soft drinks may be predicted based on the types of acid content, pH value, titratable acidity, and ion concentration.
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Cher TL, Huang CS, Shih CL, Lin CP. The quality of teaching and training in hospital dental departments in Taiwan: Results from the 2008 national survey. J Dent Sci 2014. [DOI: 10.1016/j.jds.2013.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Jan YD, Lee BS, Lin CP, Tseng WY. Biocompatibility and cytotoxicity of two novel low-shrinkage dental resin matrices. J Formos Med Assoc 2014; 113:349-55. [DOI: 10.1016/j.jfma.2012.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 06/11/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022] Open
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Jan YD, Lee BS, Lin CP, Tseng WY. Conjugation of diisocyanate side chains to dimethacrylate reduces polymerization shrinkage and increases the hardness of composite resins. J Formos Med Assoc 2014; 113:242-8. [PMID: 24685300 DOI: 10.1016/j.jfma.2012.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/20/2012] [Accepted: 07/06/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND/PURPOSE Polymerization shrinkage is one of the main causes of dental restoration failure. This study tried to conjugate two diisocyanate side chains to dimethacrylate resins in order to reduce polymerization shrinkage and increase the hardness of composite resins. METHODS Diisocyanate, 2-hydroxyethyl methacrylate, and bisphenol A dimethacrylate were reacted in different ratios to form urethane-modified new resin matrices, and then mixed with 50 wt.% silica fillers. The viscosities of matrices, polymerization shrinkage, surface hardness, and degrees of conversion of experimental composite resins were then evaluated and compared with a non-modified control group. RESULTS The viscosities of resin matrices increased with increasing diisocyanate side chain density. Polymerization shrinkage and degree of conversion, however, decreased with increasing diisocyanate side chain density. The surface hardness of all diisocyanate-modified groups was equal to or significantly higher than that of the control group. CONCLUSION Conjugation of diisocyanate side chains to dimethacrylate represents an effective means of reducing polymerization shrinkage and increasing the surface hardness of dental composite resins.
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Lee JJ, Kok SH, Cheng SJ, Lin LD, Lin CP. Needlestick and sharps injuries among dental healthcare workers at a university hospital. J Formos Med Assoc 2014; 113:227-33. [DOI: 10.1016/j.jfma.2012.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 05/17/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022] Open
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Chang HH, Wang YL, Chiang YC, Chen YL, Chuang YH, Tsai SJ, Heish KH, Lin FH, Lin CP. A novel chitosan-γPGA polyelectrolyte complex hydrogel promotes early new bone formation in the alveolar socket following tooth extraction. PLoS One 2014; 9:e92362. [PMID: 24658174 PMCID: PMC3962413 DOI: 10.1371/journal.pone.0092362] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 02/20/2014] [Indexed: 11/18/2022] Open
Abstract
A novel chitosan-γPGA polyelectrolyte complex hydrogel (C-PGA) has been developed and proven to be an effective dressing for wound healing. The purpose of this study was to evaluate if C-PGA could promote new bone formation in the alveolar socket following tooth extraction. An animal model was proposed using radiography and histomorphology simultaneously to analyze the symmetrical sections of Wistar rats. The upper incisors of Wistar rats were extracted and the extraction sockets were randomly treated with gelatin sponge, neat chitosan, C-PGA, or received no treatment. The extraction sockets of selected rats from each group were evaluated at 1, 2, 4, or 6 wk post-extraction. The results of radiography and histopathology indicated that the extraction sockets treated with C-PGA exhibited lamellar bone formation (6.5%) as early as 2 wk after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P < 0.05) in the extraction sockets treated with C-PGA at 6 wk post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model involving symmetrical sections and simultaneous radiography and histomorphology evaluation is feasible. We also conclude that the novel C-PGA has great potential for new bone formation in the alveolar socket following tooth extraction.
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Liao YS, Lin TC, Lai CY, Chen YL, Chang HH, Lin CP. Cutting performance of diamond-like carbon coated tips in ultrasonic osteotomy. J Dent Sci 2014. [DOI: 10.1016/j.jds.2013.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Chen MH, Chang JZC, Kok SH, Chen YJ, Huang YD, Cheng KY, Lin CP. Intraobserver reliability of landmark identification in cone-beam computed tomography-synthesized two-dimensional cephalograms versus conventional cephalometric radiography: A preliminary study. J Dent Sci 2014. [DOI: 10.1016/j.jds.2013.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Cheng YA, Jee J, Hsu G, Huang Y, Chen C, Lin CP. A markerless protocol for genetic analysis of Aggregatibacter actinomycetemcomitans. J Formos Med Assoc 2014; 113:114-23. [PMID: 24530245 DOI: 10.1016/j.jfma.2012.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/09/2012] [Accepted: 05/15/2012] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND/PURPOSE The genomes of different Aggregatibacter actinomycetemcomitans (A actinomycetemcomitans) strains contain many strain-specific genes and genomic islands (defined as DNA found in some but not all strains) of unknown functions. Genetic analysis for the functions of these islands will be constrained by the limited availability of genetic markers and vectors for A actinomycetemcomitans. In this study, we tested a novel genetic approach of gene deletion and restoration in a naturally competent A actinomycetemcomitans strain D7S-1. METHODS Specific genes' deletion mutants and mutants restored with the deleted genes were constructed by a markerless loxP/Cre system. In mutants with sequential deletion of multiple genes loxP with different spacer regions were used to avoid unwanted recombinations between loxP sites. RESULTS Eight single-gene deletion mutants, four multiple-gene deletion mutants, and two mutants with restored genes were constructed. No unintended non-specific deletion mutants were generated by this protocol. The protocol did not negatively affect the growth and biofilm formation of A actinomycetemcomitans. CONCLUSION The protocol described in this study is efficient and specific for genetic manipulation of A actinomycetemcomitans, and will be amenable for functional analysis of multiple genes in A actinomycetemcomitans.
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Shin CS, Huang YH, Chi CW, Lin CP. Fatigue life enhancement of NiTi rotary endodontic instruments by progressive reciprocating operation. Int Endod J 2014; 47:882-8. [PMID: 24355085 DOI: 10.1111/iej.12233] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 12/16/2013] [Indexed: 01/29/2023]
Abstract
AIM To evaluate the effect of reciprocating amplitude and progressive angular increment on fatigue life enhancement of NiTi rotary endodontic instruments. METHODOLOGY ProTaper F2 instruments were operated in steel artificial canals with both stationary reciprocating (SR) and progressive reciprocating (PR) motions. The SR motions involved symmetric to and fro reciprocation of ± 180(o) , ± 135(o) , ± 90(o) , ± 60(o) and ± 45(o) . The PR motions were ± 45(o) stationary motion superimposed with angular increments of 7(o) , 11(o) , 22.5(o) or 31(o) whenever an instrument completed 1, 10 or 30 reciprocating cycles (rc). The fatigue lives were compared with those under continuous rotation (CR) and a reciprocating operation with a forward 144(o) and backward 72(o) motion proposed by Yared (2008). The statistical significance of these operating modes on fatigue life was examined using one way anova and post hoc Tukey's tests at P = 0.05. Fractographic analysis was also applied to probe the fracture mechanisms of different rotation motions. RESULTS Fatigue life increased with decreasing reciprocating amplitude. Operating in the SR increased fatigue life by 355% over that in the CR. Except for the 22.5(o) increment, all PR motions yielded longer fatigue lives than the SR motion. A progressive reciprocating operation with a ± 45(o) reciprocating amplitude and a + 7(o) progressive angular increment every 10 reciprocating cycles (± 45(o) /10rc/+7(o) ) increased fatigue life by 990% over that in the CR motion. In terms of life enhancement over the CR motion, the larger the curvature the less are the differences between different movements. Single crack initiation sites were found in the CR and SR motions, while three crack initiation sites were typical in the ± 45(o) /10rc/+7(o) motion. CONCLUSIONS Fatigue life increased with decreasing reciprocating amplitude in stationary reciprocation. A progressive reciprocating operation with ± 45(o) /10rc/+7(o) motion led to significant fatigue life enhancement and multiple fatigue crack initiation in NiTi endodontic instruments.
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Chen YY, Chen WP, Chang HH, Huang SH, Lin CP. A novel dental implant abutment with micro-motion capability—Development and biomechanical evaluations. Dent Mater 2014; 30:131-7. [DOI: 10.1016/j.dental.2013.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 10/18/2013] [Accepted: 10/18/2013] [Indexed: 11/28/2022]
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Yao Y, Lu WL, Xu B, Li CB, Lin CP, Waxman D, Feng JF. The increase of the functional entropy of the human brain with age. Sci Rep 2013; 3:2853. [PMID: 24103922 PMCID: PMC3793229 DOI: 10.1038/srep02853] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/10/2013] [Indexed: 11/09/2022] Open
Abstract
We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy.
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Huang CS, Cher TL, Lin CP, Wu KM. Projection of the dental workforce from 2011 to 2020, based on the actual workload of 6762 dentists in 2010 in Taiwan. J Formos Med Assoc 2013; 112:527-36. [PMID: 23910070 DOI: 10.1016/j.jfma.2013.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/06/2013] [Accepted: 06/10/2013] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND/PURPOSE Planning of the dental workforce, especially the number of dentists, requires the data of actual dental workloads. This study attempts to make projections of the dental workforce from 2011 to 2020, based on a survey of the actual workload of 6762 dentists in 2010. METHODS In 2010, a database of 11,449 current dentists was retrieved from the file of Department of Health, Executive Yuan, Taipei, Taiwan. Questionnaires with the information of each dentist and 10 questions regarding the actual workload were sent to each dentist with a return envelope. The actual workload of the dentists who returned the questionnaires was analyzed. A projection of dental workforce from 2011 to 2020 was calculated, based on the actual workload. RESULTS An analysis of the actual dental workload was conducted on 6762 (59.1%) returned questionnaires. The dentist-to-population ratio (defined as the number of dentists per 10,000 people) was 5.0 in 2010. The supply of 400 dentists per year remained constant from 2006 to 2010, and is expected to be sustained for the next 10 years. Because the population of Taiwan will begin to decrease within the next 10 years, we estimate that the dentist-to-population ratio will increase to 6.0 by the year 2020 or earlier. After adjusting for working hours, working days, and gender differences, surplus dentists will number approximately 1069 in 2020. CONCLUSION An oversupply of dentists and a decrease in population will result in a surplus of dentists. To make better projections of the dental workforce, surplus dentists can be arranged to care for the aged, disabled people, and underserved people.
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Chen YL, Chang HH, Chiang YC, Lin CP. Application and development of ultrasonics in dentistry. J Formos Med Assoc 2013; 112:659-65. [PMID: 23810702 DOI: 10.1016/j.jfma.2013.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/07/2013] [Accepted: 05/11/2013] [Indexed: 12/16/2022] Open
Abstract
Since the 1950s, dentistry's ultrasonic instruments have developed rapidly. Because of better visualization, operative convenience, and precise cutting ability, ultrasonic instruments are widely and efficiently applied in the dental field. This article describes the development and improvement of ultrasonic instruments in several dental fields. Although some issues still need clarification, the results of previous studies indicate that ultrasonic instruments have a high potential to become convenient and efficient dental tools and deserve further development.
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Chen WP, Chen YY, Huang SH, Lin CP. Limitations of Push-out Test in Bond Strength Measurement. J Endod 2013; 39:283-7. [DOI: 10.1016/j.joen.2012.11.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/02/2012] [Accepted: 11/06/2012] [Indexed: 11/29/2022]
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Cher TL, Lai EHH, Wang CY, Huang CS, Lin CP. Administrative management of dental departments in hospitals in Taiwan: A field survey. J Dent Sci 2012. [DOI: 10.1016/j.jds.2012.01.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Lin PY, Cheng YW, Chu CY, Chien KL, Lin CP, Tu YK. In-office treatment for dentin hypersensitivity: a systematic review and network meta-analysis. J Clin Periodontol 2012; 40:53-64. [DOI: 10.1111/jcpe.12011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2012] [Indexed: 11/30/2022]
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Sadhasivam S, Chen JC, Savitha S, Hsu MX, Hsu CK, Lin CP, Lin FH. Synthesis of partial stabilized cement-gypsum as new dental retrograde filling material. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012; 32:1859-1867. [PMID: 34062667 DOI: 10.1016/j.msec.2012.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 02/01/2012] [Accepted: 05/04/2012] [Indexed: 10/28/2022]
Abstract
The study describes the sol-gel synthesis of a new dental retrograde filling material partial stabilized cement (PSC)-gypsum by adding different weight percentage of gypsum (25% PSC+75% gypsum, 50% PSC+50% gypsum and 75% PSC+25% gypsum) to the PSC. The crystalline phase and hydration products of PSC-gypsum were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The handling properties such as setting time, viscosity, tensile strength, porosity and pH, were also studied. The XRD and microstructure analysis demonstrated the formation of hydroxyapatite and removal of calcium dihydrate during its immersion in simulated body fluid (SBF) on day 10 for 75% PSC+25% gypsum. The developed PSC-gypsum not only improved the setting time but also greatly reduced the viscosity, which is very essential for endodontic surgery. The cytotoxic and cell proliferation studies indicated that the synthesized material is highly biocompatible. The increased alkaline pH of the PSC-gypsum also had a remarkable antibacterial activity.
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Tsai SJ, Chen YL, Chang HH, Shyu YC, Lin CP. Effect of piezoelectric instruments on healing propensity of alveolar sockets following mandibular third molar extraction. J Dent Sci 2012. [DOI: 10.1016/j.jds.2012.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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