Min-Huey Chen

National Taiwan University, T’ai-pei, Taipei, Taiwan

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Publications (36)87.34 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Traditional dental care, which includes long-term oral hygiene maintenance and scheduled dental appointments, requires effective communication between dentists and patients. In this study, a new system was designed to provide a platform for direct communication between dentists and patients. A new mobile app, Dental Calendar, combined with cloud services specific for dental care was created by a team constituted by dentists, computer scientists, and service scientists. This new system would remind patients about every scheduled appointment, and help them take pictures of their own oral cavity parts that require dental treatment and send them to dentists along with a symptom description. Dentists, by contrast, could confirm or change appointments easily and provide professional advice to their patients immediately. In this study, 26 dentists and 32 patients were evaluated by a questionnaire containing eight dental-service items prior to and after using this system. Paired sample t test was used for statistical analysis. After using the Dental Calendar combined with cloud services, dentists were able to improve appointment arrangements significantly, taking care of the patients with sudden worse prosthesis (p < 0.05). Patients also achieved significant improvement in appointment reminder systems, rearrangement of appointments in case of sudden worse prosthesis, and establishment of a direct relationship with dentists (p < 0.05). Our new mobile app, Dental Calendar, in combination with cloud services, provides efficient service to both dentists and patients, and helps establish a better relationship between them. It also helps dentists to arrange appointments for patients with sudden worsening of prosthesis function.
    Journal of the Formosan Medical Association 05/2014; · 1.00 Impact Factor
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    ABSTRACT: Traditionally, tooth germ is observed by histological investigation with hematoxylin and eosin stain and information may loss during the process. The purpose of this study is to use multiphoton laser fluorescence microscopy to observe the developing tooth germs of mice for building up the database of the images of tooth germs and compare with those from conventional histological analysis. Tooth germs were isolated from embryonic and newborn mice with age of Embryonic Day 14.5 and Postnatal Days 1, 3, 5, and 7. Comparison of the images of tooth germ sections in multiphoton microscopy with the images of histology was performed for investigating the molar tooth germs. It was found that various signals arose from different structures of tooth germs. Pre-dentin and dentin have strong second-harmonic generation signals, while ameloblasts and enamel tissues were shown with strong autofluorescence signals. In this study, a novel multiphoton microscopy database of images from developing tooth germs in mice was set up. We confirmed that multiphoton laser microscopy is a powerful tool for investigating the development of tooth germ and is worthy for further application in the study of tooth regeneration.
    Journal of the Formosan Medical Association 01/2014; 113(1):42-9. · 1.00 Impact Factor
  • Tai-Ting Lai, Min-Huey Chen
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    ABSTRACT: Background/purpose The purpose of this retrospective study was to evaluate the factors affecting the clinical success of orthodontic anchorage by using temporary anchorage devices (TADs). Materials and methods One hundred and twenty nine consecutive patients (54 males, 75 females; mean age, 20.2 years old) with a total of 266 TADs of three different types were examined. The variables related to TAD success were assessed through five categories: implant-related (type 1, type 2, and type 3 with different diameters and lengths), patient-related (sex, age, and type of malocclusion), location-related (jaw, site, side, bone quality, and the type of soft tissue), orthodontic-related (the timing of force application), and implant-maintenance factors (local inflammation around a TAD: mild, moderate, and severe). Results The overall success rates were 97%. The clinical variables of all implant-related factors (diameter and length), all patient-related factors (sex, age, and type of malocclusion), and one of location-related factors (side) did not show any statistically significant difference in success rates. The clinical variables of most location-related factors [jaw (mandible), site (lingual), bone quality (Q4), and the type of soft tissue around TADs (mucosa)], orthodontic-related factors [timing of force application equal to 2 weeks)], and implant-maintenance factors [local inflammation (mild–moderate and moderate–severe)] showed less success with statistically significant differences. Conclusion In order to improve the success rates, local inflammation should be monitored and controlled, force application should be 4 weeks after insertion, and the location for placement of TADs should be good quality bone with keratinized mucosa.
    Journal of Dental Sciences. 01/2014; 9(1):49–55.
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    ABSTRACT: Background/Purpose Novel liquid crystalline epoxy nanocomposites, which exhibit reduced polymerization shrinkage and effectively bond to tooth structures, can be applied in esthetic dentistry, including core and post systems, direct and indirect restorations, and dental brackets. The purposes of this study were to investigate the properties of liquid crystalline epoxy nanocomposites including biocompatibility, microhardness, and frictional forces of bracket-like blocks with different filler contents for further clinical applications. Methods In this study, we evaluated liquid crystalline epoxy nanocomposite materials that exhibited various filler contents, by assessing their cell activity performance using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and their microhardness with or without thermocycling. We also evaluated the frictional force between bracket-like duplicates and commercially available esthetic bracket systems using Instron 5566. Results The liquid crystalline epoxy nanocomposite materials showed good biocompatibility. The materials having high filler content demonstrated greater microhardness compared with commercially available bracket materials, before and after the thermocycling treatment. Thus, manufacturing processes are important to reduce frictional force experienced by orthodontic brackets. Conclusion The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment.
    Journal of the Formosan Medical Association 01/2014; · 1.00 Impact Factor
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    ABSTRACT: Background/Purpose Traditional dental care, which includes long-term oral hygiene maintenance and scheduled dental appointments, requires effective communication between dentists and patients. In this study, a new system was designed to provide a platform for direct communication between dentists and patients. Methods A new mobile app, Dental Calendar, combined with cloud services specific for dental care was created by a team constituted by dentists, computer scientists, and service scientists. This new system would remind patients about every scheduled appointment, and help them take pictures of their own oral cavity parts that require dental treatment and send them to dentists along with a symptom description. Dentists, by contrast, could confirm or change appointments easily and provide professional advice to their patients immediately. In this study, 26 dentists and 32 patients were evaluated by a questionnaire containing eight dental-service items prior to and after using this system. Paired sample t test was used for statistical analysis. Results After using the Dental Calendar combined with cloud services, dentists were able to improve appointment arrangements significantly, taking care of the patients with sudden worse prosthesis (p < 0.05). Patients also achieved significant improvement in appointment reminder systems, rearrangement of appointments in case of sudden worse prosthesis, and establishment of a direct relationship with dentists (p < 0.05). Conclusion Our new mobile app, Dental Calendar, in combination with cloud services, provides efficient service to both dentists and patients, and helps establish a better relationship between them. It also helps dentists to arrange appointments for patients with sudden worsening of prosthesis function.
    Journal of the Formosan Medical Association. 01/2014;
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    ABSTRACT: Our previous work has demonstrated that rat bone marrow stem cells (BMSCs) can transdifferentiate into α-amylase-producing cells after coculture with rat submandibular gland acinar cells. These transdifferentiated cells may be used for regeneration of damaged salivary gland. The purpose of this study was to investigate the global gene expression of rat BMSCs cocultured with rat submandibular gland acinar cells and the factors inducing this transdifferentiation. Rat BMSCs were indirectly cocultured with rat submandibular gland acinar cells by using the double chamber system for 5 and 10 days. The global gene expression of BMSCs during transdifferentiation into acinar cells was investigated by microarray analysis. A total of 45,018 probes were used and 41,012 genes were detected. After coculture for 5 days, 1409 genes were upregulated more than twofold and 1417 genes were downregulated more than twofold (p<0.005). Moreover, after coculture for 10 days, 1356 genes were upregulated more than twofold and 1231 genes were downregulated more than twofold (p<0.005). Bone morphogenetic protein (BMP)-6 was one of the top-ranked upregulated genes. The hub genes were interleukin-6 and CCAAT/enhancer-binding protein β (CEBPB) in the early and late response gene groups, respectively. This is believed to be the first study on the global gene expression of rat BMSCs cocultured with rat acinar cells. Many genes related to the function of salivary acinar cells such as those responsible for the production of α-amylase protein were upregulated and many genes related to the differentiation of BMSCs into adipocytes and osteoblasts were downregulated. In addition, BMP-6 gene was found to be highly upregulated. We proposed that three target genes, BMP-6, interleukin-6 and CEBPB, play important roles in the transdifferentiation of BMSCs into acinar cells, and are worthy of further investigation.
    Journal of the Formosan Medical Association 11/2013; 112(11):713-20. · 1.00 Impact Factor
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    ABSTRACT: This research was designed to investigate the effects of low pressure radio-frequency (RF) oxygen plasma treatment (OPT) on the surface of commercially pure titanium (CP-Ti) and Ti6Al4V. Surface topography, elemental composition, water contact angle, cell viability, and cell morphology were surveyed to evaluate the biocompatibility of titanium samples with different lengths of OP treating time. CP-Ti and Ti6Al4V discs were both classified into 4 groups: untreated, treated with OP generated by using oxygen (99.98%) for 5, 10, and 30 min, respectively. After OPT on CP-Ti and Ti6Al4V samples, scanning probe microscopy, X-ray photoelectron spectrometry (XPS), and contact angle tests were conducted to determine the surface topography, elemental composition and hydrophilicity, respectively. The change of surface morphology was further studied using sputtered titanium on silicon wafers. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and F-actin immunofluorescence stain were performed to investigate the viability and spreading behavior of cultivated MG-63 cells on the samples. The surface roughness was most prominent after 5 min OPT in both CP-Ti and Ti6Al4V, and the surface morphology of sputtered Ti sharpened after the 5 min treatment. From the XPS results, the intensity of Ti(°), Ti(2+), and Ti(3+) of the samples' surface decreased indicating the oxidation of titanium after OPT. The water contact angles of both CP-Ti and Ti6Al4V were increased after 5 min OPT. The results of MTT assay demonstrated MG-63 cells proliferated best on the 5 min OP treated titanium sample. The F-actin immunofluorescence stain revealed the cultivated cell number of 5 min treated CP-Ti/Ti6Al4V was greater than other groups and most of the cultivated cells were spindle-shaped. Low pressure RF oxygen plasma modified both the composition and the morphology of titanium samples' surface. The CP-Ti/Ti6Al4V treated with 5 min OPT displayed the roughest surface, sharpest surface profile and best biocompatibility.
    PLoS ONE 01/2013; 8(12):e84898. · 3.73 Impact Factor
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    ABSTRACT: BACKGROUND: Epithelial invagination is important for initiation of ectodermal organogenesis. Although many factors regulate ectodermal organogenesis, there is not any report about their functions in real-time study. Electric cell-substrate impedance sensing (ECIS), a non-invasive, real-time surveillance system, had been used to detect changes in organ cell layer thickness through quantitative monitoring of the impedance of a cell-to-microelectrode interface over time. It was shown to be a good method for identifying significant real-time changes of cells. The purpose of this study is to establish a combined bioengineered organ-ECIS model for investigating the real time effects of fibroblast growth factor-9 (FGF-9) on epithelial invagination in bioengineered ectodermal organs. We dissected epithelial and mesenchymal cells from stage E14.5 murine molar tooth germs and identified the real-time effects of FGF-9 on epithelial-mesenchymal interactions using this combined bioengineered organ-ECIS model. RESULTS: Measurement of bioengineered ectodermal organ thickness showed that Fibroblast growth factor-9 (FGF-9) accelerates epithelial invagination in reaggregated mesenchymal cell layer within 3 days. Gene expression analysis revealed that FGF-9 stimulates and sustains early Ameloblastin and Amelogenin expression during odontogenesis. CONCLUSIONS: This is the first real-time study to show that, FGF-9 plays an important role in epithelial invagination and initiates ectodermal organogenesis. Based on these findings, we suggest FGF-9 can be applied for further study in ectodermal organ regeneration, and we also proposed that the 'FGF-BMP balancing system' is important for manipulating the morphogenesis of ectodermal organs. The combined bioengineered organ-ECIS model is a promising method for ectodermal organ engineering and regeneration research.
    Cell Communication and Signaling 11/2012; 10(1):34. · 5.09 Impact Factor
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    ABSTRACT: Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility, comparable to commercialized composites. The results indicate that this novel LC nanocomposite is worthy of development and has potential for further applications in clinical dentistry.
    Acta biomaterialia 07/2012; 8(11):4151-61. · 5.09 Impact Factor
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    ABSTRACT: Previous studies have shown that zinc chloride (ZnCl(2)) can induce metallthionein (MT) in the liver and kidney to protect tissues against toxicants and shows a better corneal wound healing than conventional drugs do. We hypothesized that ZnCl(2) can promote odontogenesis of dental pulp stem cells (DPSCs) via MT. The purpose of this study was to investigate the effects of ZnCl(2) on human DPSCs and the expression of MT. DPSCs were isolated by flow cytometry with selective surface marker CD146 and STRO-1. After they grew into confluence, DPSCs were induced into odontoblasts with or without ZnCl(2) supplemented in the culture medium for 21 days. The effect of ZnCl(2) on DPSCs differentiation was examined followed by alkaline phosphatase staining/activity and quantitative real-time polymerase chain reaction analysis. By treating DPSCs with ZnCl(2), the duration of mineralization was shortened and expressions of differentiation markers into odontoblasts were more significant than those without ZnCl(2) stimulation. Besides, the MT gene expression was increased with the increasing expressions of odontoblasts' markers after treated with ZnCl(2). This was the first report that ZnCl(2) could promote odontoblastic differentiation of DPSCs through the up-regulation of gene MT.
    Journal of endodontics 02/2011; 37(2):211-6. · 2.95 Impact Factor
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    ABSTRACT: Growth factors and morphogens secreted by bone marrow mesenchymal stem cells (BMSCs) of bone marrow fluid may promote tooth regeneration. Accordingly, a tissue engineering approach was utilized to develop an economical strategy for obtaining the growth factors and morphogens from BMSCs. Unerupted second molar tooth buds harvested from miniature pigs were cultured in vitro to obtain dental bud cells (DBCs). Bone marrow fluid, which contains BMSCs, was collected from the porcine mandible before operation. DBCs suspended in bone marrow fluid were seeded into a gelatin/chondoitin-6-sulfate/hyaluronan tri-copolymer scaffold (GCHT scaffold). The DBCs/bone marrow fluid/GCHT scaffold was autografted into the original alveolar sockets of the pigs. Radiographic and histological examinations were applied to identify the structure of regenerated tooth at 40 weeks postimplantation. The present results showed that one pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessel, and periodontal ligament in indiscriminate shape. Three animals had an unerupted tooth that expressed dentin matrix protein-1, vascular endothelial growth factor, and osteopontin; and two other pigs also had dental-like structure with dentin tubules. This study reveals that DBCs adding bone marrow fluid and a suitable scaffold can promote the tooth regeneration in autogenic cell transplantation.
    Artificial Organs 11/2010; 35(2):113-21. · 1.96 Impact Factor
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    ABSTRACT: Human mesenchymal stem cells (hMSCs) are characterized by their abilities to differentiate into different lineages, including osteoblasts. Besides soluble factors, mechanical strain and extracellular matrix (ECM) proteins play important roles in osteogenic differentiation of hMSCs. However, interactions between them are still not fully understood. The purpose of this study was to investigate the combined effects of insoluble chemical and mechanical factors (ECM proteins vs. cyclic stretching) in driving hMSCs into osteogenic differentiation. To avoid the influence from osteogenic supplements, hMSCs were cultured in regular medium and subjected to cyclic mechanical stretching using a Flexcell Tension system (3% elongation at 0.1 Hz) when they were grown on substrates coated with various ECM proteins (collagen I (Col I), vitronectin (VN), fibronectin (FN), and laminin (LN)). Using alkaline phosphatase (ALP) activity and mineralized matrix deposition as respective indicators of the early and late stages of osteogenesis, we report herein that all of the ECM proteins tested supported hMSC differentiation into osteogenic phenotypes in the absence of osteogenic supplements. Moreover, cyclic mechanical stretching activated the phosphorylation of focal adhesion kinase (FAK), upregulated the transcription and phosphorylation of core-binding factor alpha-1 (Cbfa1), and subsequently increased ALP activity and mineralized matrix deposition. Among the ECM proteins tested, FN and LN exhibited greater effects of supporting stretching-induced osteogenic differentiation than did Col I and VN. The ability of ECM proteins and mechanical stretching to regulate osteogenesis in hMSCs can be exploited in bone tissue engineering via approximate matrix design or application of mechanical stimulation.
    Journal of Cellular Biochemistry 09/2009; 108(6):1263-73. · 3.06 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the behaviors of rat tooth germ (TG) cells cultured on poly(vinyl alcohol) (PVA). It was found that TG cells suspended and aggregated to form three-dimensional spheroids on PVA. Compared with traditional monolayered cells on tissue culture polystyrene, TG cell spheroids on PVA obviously increased the alkaline phosphatase activity, the degree of mineralization, and upregulated both osteopontin and dentin matrix protein 1 genes, regardless of the seeding density. Surprisingly, PVA appears to activate the alkaline phosphatase activity and mineralization effects on TG cell spheroids in the absence of a differentiation medium. Furthermore, the present study indicates that integrins may play an important role in the mineralization on TG cell spheroids by adding Arg-Gly-Asp (RGD) peptides. Therefore, the information presented here should help to clarify the role of PVA in the regulation of the mineralization, differentiation and integrin-mediation of TG cells.
    Acta biomaterialia 01/2009; 5(4):1064-74. · 5.09 Impact Factor
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    Rung-Shu Chen, Min-Huey Chen, Tai-Horng Young
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    ABSTRACT: Poly(vinyl alcohol) (PVA) has been widely used in the field of biomedical applications because of its hydrophilic properties for desired functions. Nonetheless, the role of PVA in tooth germ (TG) cell differentiation and mineralization has seldom been explored. To test the capacity of PVA in regulating TG cell differentiation and mineralization, TG cells obtained from 4-day-old Wistar rats were cultured on the PVA substrate. It was found that PVA was able to promote TG cell exhibiting high levels of alkaline phosphatase (ALP) activity, mineralization, and mRNA expression of osteocalcin (OCN), osteopontin (OPN), dentin matrix protein 1 (DMP1) and enamelin. Even when the additives routinely administrated in the differentiation medium such as dexamethasone, beta-glycerophosphate and ascorbic acid were removed from the culture system, PVA itself still stimulated TG cells with the differentiation and mineralization ability. By showing the direct suppression of extracellular signaling-regulated kinase1/2 (ERK1/2) of TG cells treated with U0126, known to suppress the activation of ERK1/2, and significant synergistic effects between PVA and U0126, we demonstrated the suppression of ERK1/2 pathway is one of the effects of PVA-promoted TG cell differentiation and mineralization. Taken together, this study demonstrated a novel role of PVA in promoting the differentiation and mineralization of TG cells through ERK1/2 acting as a negative regulator.
    Biomaterials 12/2008; 30(4):541-7. · 8.31 Impact Factor
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    ABSTRACT: Tissue engineering of salivary glands offers the potential for future use in the treatment of patients with salivary hypofunction. Biocompatible materials that promote acinar cell aggregation and function in vitro are an essential part of salivary gland tissue engineering. In this study, rat parotid acinar cells assembled into three-dimensional aggregates above the polyvinyl alcohol (PVA)-coated surface. These aggregates developed compact acinar cell spheroids resembling in vivo physiological condition, which were different from the traditional monolayered morphology in vitro. Cells remained viable and with better functional activity in response to acetylcholine in the spheroids and could form monolayered acinar cells when they were reinoculated on tissue culture polystyrene wells. To interpret the phenomenon further, we proposed that the formation of acinar cell spheroids on the PVA is mediated by a balance between two competing forces: the interactions of cell-PVA and cell-cell. This study demonstrated the formation of functional cell spheroids above a PVA-coated surface may provide an in vitro system for investigating cell behaviors for tissue engineering of artificial salivary gland.
    Journal of Biomedical Materials Research Part A 08/2008; 90(4):1066-72. · 2.83 Impact Factor
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    ABSTRACT: The purpose of this study was to explore the influences of cyclic mechanical stretching on the mRNA expressions of tendon/ligament-related and osteoblast-specific marker genes in human MSCs seeded onto a collagen type I-coated surface. The stretch-induced mRNA expressions of mesenchymal stem cell protein (MSCP), matrix metalloproteinase-3 (MMP-3), and marker genes related to tendon/ligament cells (type I collagen, type III collagen, and tenascin-C) and those typical of osteoblasts (core binding factor alpha 1 (Cbfa1), alkaline phosphatase (ALP), and osteocalcin (OCN)) were analyzed by quantitative real-time PCR. The results revealed significant downregulation of MSCP and upregulation of MMP-3 genes in MSCs subjected to mechanical loading, regardless of the magnitude of the stretching (high or low). Moreover, the typical marker genes of the osteoblast lineage were upregulated by low-magnitude stretching, whereas tendon/ligament-related genes were upregulated by high-magnitude stretching for a long period. Cbfa1 and ALP were upregulated starting as early at 8 hr, followed by a downward trend and no significant change in expression at the other time points. The mRNA expressions of type I collagen, type III collagen, and tenascin-C significantly increased in MSCs subjected to 10% stretching for 48 hr, and this effect still existed after the stretched cells had rested for 48 hr. This study demonstrated the effect of cyclic mechanical stretching on differential transcription of marker genes related to different cell lineages. Low-magnitude stretching increased mRNA expressions of Cbfa1 and ALP and was possibly involved in the early osteoblastic differentiation of MSCs, whereas high-magnitude stretching upregulated the mRNA expressions of tendon/ligament-related genes.
    Connective tissue research 02/2008; 49(1):7-14. · 1.55 Impact Factor
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    ABSTRACT: The purpose of this study is to use a tissue engineering approach for tooth regeneration. The swine dental bud cells (DBCs) were isolated from the developing mandibular teeth, expanded in vitro, and cultured onto cylinder scaffold gelatin-chrondroitin-hyaluronan-tri-copolymer (GCHT). After culturing in vitro, the DBCs/GCHT scaffold was autografted back into the original alveolar socket. Hematoxylin and eosin (H&E) staining combined with immunohistochemical staining were applied for identification of regenerated tooth structure. After 36-week post-transplantation, tooth-like structures, including well-organized dentin-pulp complex, cementum, and periodontal ligament, were evident in situ in two of six experimental animals. The size of the tooth structure (1 x 0.5 x 0.5 cm(3) and 0.5 x 0.5 x 0.5 cm(3) size) appeared to be dictated by the size of the GCHT scaffold (1 x 1 x 1.5 cm(3)). The third swine was demonstrated with irregular dentin-bony like calcified tissue about 1 cm in diameter without organized tooth or periodontal ligament formation. The other three swine in the experimental group showed normal bone formation and no tooth regeneration in the transplantation sites. The successful rate of tooth regeneration from DBCs/GCHT scaffolds' was about 33.3%. In the control group, three swine's molar teeth buds were removed without DBCs/GCHT implantation, the other three swine received GCHT scaffold implants without DBCs. After evaluation, no regenerated tooth was found in the transplantation site of the control group. The current results using DBSs/GCHT scaffold autotransplantation suggest a technical breakthrough for tooth regeneration.
    Journal of Biomedical Materials Research Part A 12/2007; 86(4):1062-8. · 2.83 Impact Factor
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    ABSTRACT: The aim of the study was to compare the monomer conversion and cytotoxicity of two resin composites, Tetric Ceram (TC) and Heliomolar (HM), irradiated with a halogen light-curing unit (Optilux 501) using a number of curing modes, boost (OB), ramp (OR), and conventional (OC), as well as a light-emitting diode (LED) curing unit (LEDemetron; LEDe). The effects of irradiation times (10, 20, 30, and 40 s) were also investigated. The monomer conversion of resin composites was measured using Fourier transform infrared (FTIR) analysis. Resin samples were preimmersed in Dulbeco's modified engles medium (DMEM) for 24 h, and the periodontal ligament cells (PDL) were cultured with aged medium for 72 h to evaluate the cytotoxic effects of resin samples using the microtiter-tetrazolium (MTT) method. The spectral outputs of the curing units were also compared. After irradiation using the same curing mode, the TC monomer conversion was higher than the HM analog. The TC conversion value was lower after OC and LEDemetron irradiation for 10 s compared to exposures of 30 and 40 s. The HM conversion value was lowest for the 10-s OC irradiation, and highest for the 40-s OC exposure. In cytotoxicity tests, the negative control group was without irradiation. The succinate dehydrogenase (SDH) activities of the OB and OR-irradiated TC samples were significantly lower than analogs irradiated with LEDemetron for 40 s; however, no significant differences were demonstrated between OB, OR, and control groups. Further, no significant differences in SDH activity were demonstrated for OB, OR, and control groups of the HM.
    Journal of Biomedical Materials Research Part B Applied Biomaterials 11/2007; 83(1):85-90. · 2.31 Impact Factor
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    ABSTRACT: This is the first study to explore the effect of biomaterial on tooth germ cell adhesion and proliferation in vitro. The purpose of this study is to evaluate the effects of cell-surface interactions of tooth germ cells on biomaterials with various surface hydrophilicities. The biomaterials used in this study included polyvinyl alcohol (PVA), poly(lactic-co-glycolic acid) (PLGA), poly(ethylene-co-vinyl alcohol; EVAL), and polyvinylidene fluoride (PVDF). Cell morphology was observed by photomicroscopy. Cell growth was assayed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction activity and the characteristic expression of amelogenin and collagen type I in tooth germ cells was investigated using immunocytochemistry. The results indicated that adhesion and proliferation of tooth germ cells to biomaterials with moderate hydrophilicity/hydrophobicity was superior compared to most hydrophobic material PVDF or mosthydrophilic material PVA in this study. Cellular adhesion and proliferation was evident on all tested biomaterials except PVA. The cell spheroids on PVA appeared not to be proliferated and remained as well as reattachable to tissue culture plates. In conclusion, biomaterials with moderate hydrophilicity are suitable for adhesion and proliferation of tooth germ cells. The material PVA may be a good biomaterial for maintaining tooth germ cells in three-dimensional biological restoration.
    Journal of Biomedical Materials Research Part A 11/2007; 83(1):241-8. · 2.83 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the tensile bond strength of composite inlays to human dentin with two different cavity preparation tools (bur versus Er, Cr: YSGG laser) and with two different bonding procedures (total-etch: Variolink II versus self-etch: Maxcem). The specimens were divided into four groups: bur-cut/Variolink II, bur-cut/Maxcem, laser-ablated/Variolink II, and laser-ablated/Maxcem. The following characteristics were then investigated: morphological change, dentin-resin cement interface, surface roughness, and tensile bond strength. Results demonstrated that the tensile bond strengths of the four groups were 19.11 +/- 5.88 MPa, 8.54 +/- 2.38 MPa, 13.72 +/- 3.43 MPa, and 12.11 +/- 3.71 MPa, respectively. We concluded that Variolink II provided higher tensile bond strength to composite inlays than Maxcem. On the other hand, the bond strength of Variolink II with dentin cavity prepared by Er, Cr: YSGG laser was statistically lower than that prepared by bur.
    Dental Materials Journal 10/2007; 26(5):746-55. · 0.81 Impact Factor

Publication Stats

337 Citations
87.34 Total Impact Points

Institutions

  • 2004–2014
    • National Taiwan University
      • • Department of Dentistry
      • • Graduate Institute of Clinical Dentistry
      • • Institute of Biomedical Engineering
      • • Department and Graduate Institute of Veterinary Medicine
      T’ai-pei, Taipei, Taiwan
  • 2003–2009
    • National Taiwan University Hospital
      • • School of Dentistry
      • • Department of Internal Medicine
      T’ai-pei, Taipei, Taiwan
  • 2005
    • Taipei Veterans General Hospital
      T’ai-pei, Taipei, Taiwan