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Introduction Although the therapeutic potential of human dental pulp stem cells (hDPSCs) has been studied for bone regeneration, the therapeutic efficiency needs further consideration and examinations for clinical applications. Thus, the aims of this study were to evaluate the effect of 2,3,5,4’-tetrahydroxystilbene-2-O-β-D-glucoside (THSG) on the osteogenic differentiation of hDPSCs and to examine the therapeutic efficiency of the THSG-enhanced osseous potential of hDPSCs in alveolar bony defects of rats. Methods Expressions of osteogenic messenger RNAs (including ALP, RUNX2, BGLAP, and AMBN) were examined by quantitative real-time polymerase chain reaction. Alizarin red S staining was conducted to analyze THSG-induced mineralization of hDPSCs. To investigate the regenerative effects of THSG-treated hDPSCs on dental alveolar bone, bony defects were created in male Sprague-Dawley rats. Defects were treated with Matrigel (Corning Inc, Corning, NY), hDPSCs, or hDPSCs + THSG. After 2 weeks, defect healing was evaluated by micro–computed tomographic and histologic analyses. Results In the cell model, THSG induced osteogenesis-associated genes (ALP, RUNX2, and BGLAP) and an enamel-related gene (AMBN), resulting in mineralization as detected by alizarin red S staining after 2 weeks of treatment. In the animal model, THSG increased all parameters of bone formation (the relative bone volume, trabecular thickness, trabecular number, and trabecular separation) in alveolar bony defects of rats. THSG not only improved the quality of newly formed bone but also the quantity of new bone. Conclusions These results showed important findings in revealing the THSG-enhanced osteogenic differentiation of hDPSCs and THSG-facilitated bone regeneration, which may provide an alternative option for cell-based regenerative therapy.

Introduction Transforming growth factor β1 (TGF-β1) plays an important role in cell proliferation, matrix formation, and odontogenesis. This study investigated the effects of TGF-β1 on stem cells from apical papilla (SCAPs) and its signaling by MEK/ERK and Smad2. Methods SCAPs were exposed to TGF-β1 with/without pretreatment and coincubation by SB431542 (an ALK5/Smad 2/3 inhibitor) or U0126 (a MEK/ERK inhibitor). Cell growth was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay or direct counting of viable cells. Collagen content was determined by using the Sircol collagen assay (Biocolor Ltd, Newtownabbey, Northern Ireland). Cell differentiation was evaluated by measuring alkaline phosphatase (ALP) activity. Smad2 and ERK1/2 phosphorylation was analyzed by Western blotting or PathScan phospho–enzyme-linked immunosorbent assay (Cell Signaling Technology Inc, Danvers, MA). Results TGF-β1 stimulated the growth and collagen content of cultured SCAPs. TGF-β1 stimulated ERK1/2 and Smad2 phosphorylation within 60 minutes of exposure. Pretreatment by U0126 and SB431542 effectively prevented the TGF-β1–induced cell growth and collagen content in SCAPs. TGF-β1 stimulated ALP activity at lower concentrations (0.1–1 ng/mL) but down-regulated ALP at higher concentrations (>5 ng/mL). U0126 prevented 0.5 ng/mL TGF-β1–induced ALP activity but showed little effect on 10 ng/mL TGF-β1–induced decline of ALP in SCAPs. Interestingly, SB431542 attenuated both the stimulatory and inhibitory effects on ALP by TGF-β1. Conclusions TGF-β1 may affect the proliferation, collagen turnover, and differentiation of SCAPs via differential activation of ALK5/Smad2 and MEK/ERK signaling. These results highlight the future use of TGF-β1 and SCAP for engineering of pulpal regeneration and apexogenesis.

Introduction Human dental pulp stem cells (DPSCs) have been reported to be useful material for future regenerative medicine. Clinically, cryopreservation of intact teeth can successfully preserve the periodontal ligament for future autotransplantation; however, the effects of cryopreservation procedure on the properties of DPSCs are still unclear. The aim of this study was to test whether DPSCs isolated from cryopreserved teeth can express stem cell–specific markers. Methods In this study, a novel programmable freezer coupled to a magnetic field was used to perform the cryopreservation experiments. The tested DPSCs were isolated from magnetically cryopreserved and non-cryopreserved fresh teeth with an enzyme digestion procedure. The success rate of isolation, growth curves, morphology, stem cell–specific markers, and the differentiation capacity of the isolated cells were evaluated and compared. Results The isolation rate of dental pulp cells from magnetically cryopreserved teeth was 73%. After culture for 5 generations, there was no significant difference in cell viability between cells isolated from magnetically cryopreserved teeth and those isolated from fresh teeth. There were also no visible differences between the 2 groups of dental pulp cells in morphology, expression of stem cell markers, or osteogenic and adipogenic differentiations. Conclusions The results suggest that cryopreserved whole teeth can be used for autotransplantation and provide a viable source of DPSCs.

Introduction This study evaluates the radiopacity and cytotoxicity of Portland cements containing a radiopacifier of bismuth oxide (Bi 2 O 3 ) with yttria-stabilized zirconia (YSZ) dopant. Methods Various radiopacifier powders of Bi 2 O 3 with 0%, 15%, 30%, and 100% YSZ dopant were prepared by solid-state reaction at 700°C for 12 hours and characterized by x-ray diffraction. Portland cement/radiopacifier/calcium sulfate (75/20/5) were mixed and set by deionized water. Changes in radiopacity and in vitro cell viability of the hydrated cements were assessed. An average of 6 measured equivalent thickness of aluminum (N = 6) capable of producing similar radiographic density was recorded. The cytotoxicity of each material was determined in MC3T3 E1 cell-based methyl-thiazol-tetrazolium assay. Results The x-ray diffraction patterns of YSZ doped Bi 2 O 3 are different from those of pure Bi 2 O 3 and YSZ. The cement-containing radiopacifier of Bi 2 O 3 /YSZ (85/15) presented significantly greater radiopacity ( P 2 O 3 . The mouse osteoblastic cell (MC3T3-E1) viabilities of these 2 groups were statistically similar ( P Conclusions The radiopacifier of Bi 2 O 3 /YSZ (85/15) reveals higher radiopacity but similar cell viability when compared with pure Bi 2 O 3 . It shows potential use as an alternative radiopacifier in root-end filling materials.

The objective of this study was to investigate the antibacterial, biocompatibility, and mechanical properties of mineral trioxide aggregate (MTA) set using a calcium lactate gluconate (CLG) solution.ProRoot white MTA (WMTA) (Dentsply Tulsa Dental, Tulsa, OK) was used as the control group; MTA-like cement was prepared by mixing Portland cement/bismuth oxide/calcium sulfate (75/20/5) as the experiment group. A solution of 23.1 wt% CLG was used as a hydration accelerant and was compared with deionized water (DDW). Changes in pH values, antibacterial properties, in vitro cell viability, and diametral tensile strength (DTS) of the hydrated cements were assessed.Like WMTA, pH values for the MTA-like cement set using DDW and the CLG solution showed minor but statistically significant differences (P.05). The antibacterial effects of hydrated specimens set by DDW and CLG against Streptococcus mutans assessed with an in vitro tube dilution test showed a significant difference in the early hydration time but no significant difference after 60 minutes (P.05). A mouse osteoblastic cell (MC3T3-E1)-based MTT assay revealed that WMTA set using CLG had significantly higher cell viability than that set using DDW (P.05). The DTS test for hydrated MTA-like cement with different liquids showed a significant difference on day 1 but no statistical difference on day 21.The results suggest that using a CLG solution as the hydration accelerant may enhance the biocompatibility but not compromise WMTA's antibacterial and mechanical properties.

Introduction Mineral trioxide aggregate (MTA) fulfills many of the ideal properties of a root end filling material and repair material for furcal perforation. However, its low cohesive property often makes it difficult to handle. To improve the handling properties of MTA root canal filling materials, MTA-like cement was made, and calcium lactate gluconate (CLG) aqueous solution was used to shorten the setting time and enhance the paste viscosity. Methods CLG solution was prepared by mixing lactic acid, glucono delta lactone, and calcium oxide by wet process. The crystalline property of the CLG powder was characterized by x-ray diffraction. The MTA-like cements were prepared by mixing Portland cement/bismuth oxide/gypsum (75/20/5); ProRoot white MTA (Dentsply Tulsa Dental, Tulsa, OK) was used as a control group. The influence of various liquid phases on initial setting time, handling properties, and pH value were investigated by a Vicat needle, questionnaire of operational hand feel, and pH meter, respectively. Results By using 23.1wt% CLG solutions as a liquid phase, the setting time of white MTA was significantly decreased from 155.5 ± 5.0 to 12.3 ± 2.5 minutes. The pH values for hydrated white MTA with deionized water and 23.1 wt% CLG solutions were 12.29 ± 0.02 and 11.81 ± 0.04 at 72 hours. Conclusions The results suggest that the addition of amorphous CLG-based liquid phase provides improvement in sealing ability as well as clinical manageability of dental filling materials.

The aim of this study was to investigate fracture patterns occurring when a human upper central incisor is subjected to impact loadings at various angles. A two-dimensional finite element (FE) model of the maxillary incisor and surrounding tissues was established. The structural damping factor for the tooth was then calculated and assigned to the model. Dynamic FE analysis was performed to stimulate the associated impacts. Time-dependent traumatic forces at 0 degrees, 45 degrees, and 90 degrees labially to the long axis of the tooth were applied to the model. Von Mises's equivalent stress contours within the FE models were calculated. Our results indicated that tooth damping lagged behind peak stress by 0.05 ms. In addition, we found that impact direction played an important role in terms of outcome for the fractured incisor. These results can, in part, explain the mechanisms underlying the alternative outcomes when upper incisors are subjected to impact.