Search

The aim of this study was to investigate the effects of the incorporation of elastin-like polypeptide (ELP) on the adhesion maturation of mineral trioxide aggregates (MTA). Two types of ELPs (V125 and V125E8) were genetically synthesized. V125 consisted of 125 repeating pentapeptides (Val-Pro-Gly-Xaa-Gly) and V125E8 was functionalized with octaglutamic acid in the C-terminus of V125; both were diluted to 10 wt% in solution. Three 1.5 mm diameter holes in dentin discs were filled with MTA mixed with either a solution of ELP or deionized water. Push-out bond strength tests were performed following storage in simulated body fluid (SBF) for 1, 2, 4, and 8 weeks (n = 12). The interface between dentin and MTA was observed via scanning electron microscopy (SEM). The maturation of MTA was evaluated with a stereoscopic microscope and SEM. The incorporation of a specific ELP (V125E8) significantly increased the bond strength of MTA to dentin with regard to every maturation period (p < 0.05). The bond strength of MTA also significantly increased with a longer maturation time irrespective of ELP incorporation (p < 0.05). V125E8-incorporated MTA exhibited a more intimate interface with dentin compared to the other groups. More spindle-shaped crystal structures and thicker crystals were observed in all MTA mixtures as the storage duration increased even though V125E8 exhibited fewer crystal structures on the surface. Within the limitations of this study, the incorporation of V125E8 increased the adhesive properties of MTA and the maturation of MTA occurred regardless of ELP incorporation.

In this study, the effect of saliva contamination and cleaning procedures on the bond strength of lithium disilicate (LS2) ceramics was investigated at different timings of silane treatment...

Three-dimensionally (3D) cultured dental pulp stem cells (DPSCs) reportedly exhibit superior multi-lineage differentiation capacities and have a higher expression in regeneration-related gene categories compared to conventionally cultured DPSCs. This study aimed to evaluate the effects of various mineral trioxide aggregates (MTAs) on DPSCs cultured in 3D, assessing their cell viability and tissue mineralization properties. We examined the morphology, cell viability, alkaline phosphate (ALP) activity and qualitative alizarin red S staining assay of the DPSCs that reacted with various MTAs, which included ProRoot (PRM), Biodentine (BIO), and Well-Root PT (WRP), in two different culture plates, an ultra-low attachment plate (ULA) and a conventional monolayer plate (2D). As a control, MTA-free and IRM samples were prepared. None of the MTA groups affected the microsphere-forming characteristics of DPSCs that had been cultured in ULA. The DPSCs that were cultured in ULA showed high cell viability in all MTA groups compared to IRM. The mineralization potential was favorable in all MTA groups, with a significantly higher ALP activity among the DPSCs that were cultured in ULA. Among MTAs, the PRM group showed substantially higher ALP activity than the other MTA groups. In conclusion, our results indicate that 3D-cultured DPSCs with various MTAs showed comparable viability and mineralization capacity similar to those cultured without reacting with MTA cement.

Background The addition of bioactive glass (BG), a highly bioactive material with remineralization potential, might improve the drawback of weakening property of mineral trioxide aggregates (MTA) when it encounters with body fluid. This study aims to evaluate the effect of BG addition on physical properties of MTA. Methods ProRoot (MTA), and MTA with various concentrations of BG (1, 2, 5 and 10% BG/MTA) were prepared. Simulated body fluid (SBF) was used to investigate the effect of the storage solution on dentin remineralization. Prepared specimens were examined as following; the push-out bond strength to dentin, compressive strength, setting time solubility and X-ray diffraction (XRD) analysis. Results The 2% BG/MTA showed higher push-out bond strengths than control group after 7 days of SBF storage. The 2% BG/MTA exhibited the highest compressive strength. Setting times were reduced in the 1 and 2% BG/MTA groups, and solubility of all experimental groups were clinically acceptable. In all groups, precipitates were observed in dentinal tubules via SEM. XRD showed the increased hydroxyapatite peaks in the 2, 5 and 10% BG/MTA groups. Conclusion It was verified that the BG-added MTA increased dentin push-out bond strength and compressive strength under SBF storage. The addition of BG did not negatively affect the MTA maturation reaction; it increased the amount of hydroxyapatite during SBF maturation.

SUMMARY Two cases of complicated crown fracture of the maxillary incisors were restored using the fragment reattachment technique. Root canal treatment was performed, and the fractured fragment was bonded to the tooth structure using a dentin adhesive system and a flowable composite resin, followed by the insertion of a fiber post using dual-cured resin cement. Reattached fragments have shown reliable prognosis without inflammatory signs around bonded junctions after long-term follow-up.

The effects of the incorporation of sodium-free bioactive glass into glass ionomer cement (GIC) on the demineralized dentin are studied. Four experimental groups with various amounts of BAG in GIC were considered: BG0 group: 0 wt% (control); BG5 group: 5 wt%; BG10 group: 10 wt%; BG20 group: 20 wt%. The GIC surface and GIC-approximated demineralized dentin surfaces were evaluated using field emission scanning electron microscopy (FE–SEM). X-ray diffraction (XRD) analysis was performed to evaluate the chemical changes in the GIC-approximated dentin surface. In addition, a shear bond strength test was performed to evaluate the effects of BAG incorporation on the bond strength of GIC. FE–SEM analysis indicated that BAG-incorporated GICs formed distinct precipitates on their surface. Precipitates were also formed on the GIC-approximated demineralized dentin surface. It was more obvious when the amount of BAG increased. In the XRD analysis, fluorapatitie (FAP) peaks were detected in the BG5, BG10, and BG20 groups. There was no significant difference in the shear bond strength among all experimental groups. BAG-incorporated GIC precipitated FAP crystals underlying demineralized dentin surface without affecting bond strength. This study suggests the possibility of BAG as a beneficial additive in GIC.

Various three-dimensional (3D) culture methods have been introduced to overcome the limitations of in vitro culture and mimic in vivo conditions. This study aimed to evaluate two microsphere-forming culture methods and a monolayer culture method. We evaluated cell morphology, viability, osteo-, adipo-, and chondrogenic differentiation potential of dental pulp stem cells (DPSCs) cultured in 3D culture plates: ultra-low attachment (ULA) and U-bottomed StemFit 3D (SF) plates, and a two-dimensional (2D) monolayer plate. RNA sequencing (RNA-seq) revealed differentially expressed gene (DEG) profiles of the DPSCs. In contrast to an increasing pattern in the 2D group, cell viability in 3D groups (ULA and SF) showed a decreasing pattern, however, high multilineage differentiation was observed in both the 3D groups. RNA-seq showed significantly overexpressed gene ontology categories including angiogenesis, cell migration, differentiation, and proliferation in the 3D groups. Hierarchical clustering analysis revealed a similar DEG regulation pattern between the 3D groups, however, a comparatively different DEG was observed between the 2D and 3D groups. Taken together, this study shows that DPSCs cultured in microsphere-forming plates present superior multilineage differentiation capacities and demonstrate higher DEG expression in regeneration-related gene categories compared to that in DPSCs cultured in a conventional monolayer plate.

Background/purpose: Matrix metalloproteinases (MMPs) play a crucial role in the pathogenesis of dental caries, collapse of adhesive interface, and chemical erosion of teeth. The objective of this study was to investigate the inhibitory effect of zinc on collagen degradation. Materials and methods: Human dentin was ground and demineralized by citric acid (pH 2.0). The demineralized ground dentin was incubated in six different media: artificial saliva (AS); 5 mg/ml doxycycline in AS; 3.33, 6.82, 13.63, and 27.26 mg/ml of zinc chloride (Zn) in AS. Each group was divided into two subgroups, and active MMP-2 was incorporated into one subgroup. Specimens were incubated for 24 h, 1 week, and 2 weeks. Collagen degradation product was assessed using ELISA. The results were analyzed using repeated measured ANOVA and Duncan's post hoc analysis (α = 0.05). Results: The amount of collagen degradation was the lowest in Doxy group. Zn groups showed a significant inhibitory effect in collagen degradation for all concentrations (P

Objectives This randomized double-blinded clinical trial evaluated the bleaching efficacy and incidence of contact hypersensitivity of three kinds of bleaching toothpaste. Methods Forty-nine participants above A2 shade on the maxillary central incisor (#11) and canine (#13) were randomized into three groups: TW group (n = 15), 0.75 % HP-containing toothpaste (Toothwhole white); VL group (n = 15), 0.75 % HP-containing toothpaste (Vussen 7); and VH group (n = 17), 2.8 % of HP-containing toothpaste (Vussen 28). Participants were instructed to manually brush their teeth for 3 min, 3 times per day for 12 weeks. They were followed-up after 4 and 12 weeks. Shade measurements were performed using a spectrophotometer (SP), and data were calculated with CIELab ( Δ E a b * ) and CIEDE2000 ( Δ E 00 ) formula. Additionally, visual inspection (VI) using the Vitapan classical shade guide was also performed, and the correlation between the two measurements was analyzed by comparing the CIELab ( Δ E a b * ) values. The incidence of contact hypersensitivity at each follow-up was recorded. A mixed-effect model was performed to assess shade changes and chi-square tests for the incidence of contact hypersensitivity, respectively. Results At 12 week follow-up, all groups showed Δ E a b * above 3.46, and Δ E 00 above 2.25 for tooth #11. For tooth #13, the Δ E a b * and Δ E 00 of VH and TW groups only were above those thresholds. Shade change varied according to toothpaste and follow-up points. SP and VI showed a moderate positive correlation for L*, a*, and b*, respectively (P 0.05). Conclusions Bleaching toothpaste with higher HP yields a better shade change than other toothpaste after 12 weeks. Clinical significance The use of bleaching toothpaste with a higher HP concentration results in a better shade improvement.

Introduction The purpose of this study was to investigate the role of protein interacting with never in mitosis A-1 (PIN1) in the neuronal or glial differentiation of human dental pulp stem cells (hDPSCs) and whether PIN1 can regulate determination of neuronal sub-phenotype. Methods After magnetic-activated cell sorting to separate CD34+/c-kit+/STRO-1+ hDPSCs, cells were cultured in neurogenic medium. Differentiation was measured as Nissl staining and marker protein or mRNA expression by reverse transcriptase polymerase chain reaction, immunofluorescence, and flow cytometric analysis. Results PIN1 mRNA levels were upregulated in a time-dependent fashion during neurogenic differentiation. The PIN1 inhibitor juglone suppressed neuronal differentiation but promoted glial differentiation as assessed by the number of Nissl-positive cells and mRNA expression of neuronal markers (nestin, βIII-tubulin, and NeuN) and a glial marker (glial fibrillary acidic protein). Conversely, overexpression of PIN1 by infection with adenovirus-PIN1 increased neuronal differentiation but decreased glial differentiation. Moreover, PIN1 overexpression increased the percentage of glutamatergic and GABAergic cells but decreased that of dopaminergic cells among total NeuN-positive hDPSCs. Conclusions This is the first study to demonstrate that PIN1 overexpression induced glutamatergic and GABAergic neuronal differentiation but suppressed glial differentiation of hDPSCs, suggesting that enhancing PIN expression is important to obtain human glutamatergic and GABAergic neurons from hDPSCs.

This study evaluates the effects of various agitation methods on the adhesive layer formation of a new HEMA-free universal dentin adhesive. The µTBS of the universal adhesive, G-Premio BOND in the self-etch mode was evaluated using three agitation methods [passive agitation (PA), active agitation (AA), ultrasonic agitation (UA)], with and without aging treatment. Two-way analysis of variance revealed that aging treatment was not a statistically significant factor. Tukey's HSD test showed significant differences based on the application method, UA>AA>PA. TEM images of the PA group revealed multiple water blisters in the adhesive layers; AA and UA groups presented significantly less or no blisters within the adhesive layers; thus, AA and UA groups exhibited better bonding performance for the HEMA-free universal adhesive. It is assumed that the entrap ped blisters can be reduced with the active application of dentin adhesive, and thus improving the bonding performance.

This case report describes an innovative virtual simulation method using a computer-aided rapid prototyping (CARP) model and a computer-aided design (CAD) program for autotransplantation of an immature third molar.A compromised left mandibular second molar (#18) was extracted and replaced by autotransplantation using an immature left mandibular third molar (#17). In order to minimize the surgical time and injury to the donor tooth, a virtual 3-dimensional (3D) rehearsal surgery was planned. Cone-beam computed tomographic images were taken to fabricate the 3D printing CARP model of the donor tooth and tentative extraction socket. Subsequently, both CARP models were scanned with an intraoral scanner (CEREC Omnicam; Dentsply Sirona, Bensheim, Germany) followed by superimposition and virtual simulation of osteotomy preparation of the recipient alveolus using the CAD analysis program. During the surgery, the extraction socket was precisely prepared according to the predetermined location and dimensions via virtual simulation rehearsal surgery using CAD analysis. The donor tooth was atraumatically transplanted into the prepared socket. The follow-up examination revealed that the root developed with a normal periodontal ligament and lamina dura.Virtual simulation using a 3D printing CARP model and a CAD program could be clinically useful in autotransplantation of an immature third molar by ensuring an atraumatic and predictable surgery.

Objectives The purpose of this study was to evaluate the effect of bioactive glass (BAG)-containing composite on dentin remineralization. Methods Sixty-six dentin disks with 3 mm thickness were prepared from thirty-three bovine incisors. The following six experimental groups were prepared according to type of composite (control and experimental) and storage solutions (simulated body fluid [SBF] and phosphate-buffered saline [PBS]): 1 (undemineralized); 2 (demineralized); 3 (demineralized with control composite in SBF); 4 (demineralized with control composite in PBS); 5 (demineralized with experimental composite in SBF); and 6 (demineralized with experimental composite in PBS). BAG65S (65% Si, 31% Ca, and 4% P) was prepared via the sol-gel method. The control composite was made with a 50:50 Bis-GMA:TEGDMA resin matrix, 57 wt% strontium glass, and 15 wt% aerosol silica. The experimental composite had the same resin and filler, but with 15 wt% BAG65S replacing the aerosol silica. For groups 3–6, composite disks (20 × 10 × 2 mm) were prepared and approximated to the dentin disks and stored in PBS or SBF for 2 weeks. Micro-hardness test, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and field-emission scanning electron microscopy (FE-SEM) was investigated. Results The BAG-containing composite significantly increased the micro-hardness of the adjacent demineralized dentin. ATR-FTIR revealed calcium phosphate peaks on the surface of the groups which used BAG-containing composite. FE-SEM revealed surface deposits partially occluding the dentin surface. No significant difference was found between SBF and PBS storage. Clinical Significance Bioactive glass is a potentially useful material for remineralization of tooth structure. When incorporated into a resin composite, it may aid in remineralizing the adjacent demineralized dentin, thus preventing further destruction of the tooth. Conclusion BAG-containing composites placed in close proximity can partially remineralize adjacent demineralized dentin.

Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: https://www.nature.com/articles/s41598-018-23939-6 Restoration of hard tissue in conjunction with adhesive is a globally challenging issue in medicine and dentistry. Common clinical therapies involving application of adhesive and substitute material for functional or anatomical recovery are still suboptimal. Biomaterials with bioactivity and inhibitory effects of enzyme-mediated adhesive degradation can render a solution to this. Here, we designed a novel copper-doped bioactive glass nanoparticles (CuBGn) to offer multifunction: metalloproteinases (MMP) deactivation and remineralization and incorporated the CuBGn in resin-dentin adhesive systems, which showed most common failure of MMP mediated adhesive degradation among hard tissue adhesives, to evaluate proposed therapeutic effects. A sol-gel derived bioactive glass nanoparticles doping 10 wt% of Cu (Cu-BGn) for releasing Cu ions, which were well-known MMP deactivator, were successfully created and included in light-curing dental adhesive (DA), a filler-free co-monomer resin blend, at different concentrations (up to 2 wt%). These therapeutic adhesives (CuBGn-DA) showed enhanced (a)cellular bioactivity, cytocompatibility, microtensile bond strength and MMP deactivationability. In conclusion, the incorporation of Cu ions releasing nano-bioactive glass demonstrated multifunctional properties at the resin-dentin interface; MMP deactivation and remineralization, representing a suitable strategy to extend the longevity of adhesive-hard tissue (i.e. resin-dentin) interfaces.

All-trans retinoic acid (ATRA) inhibits matrix metalloproteinase (MMP)-2 and MMP-9 in synovial fibroblasts, skin fibroblasts, bronchoalveolar lavage cells and cancer cells, but activates MMP-9 in neuroblast and leukemia cells. Very little is known regarding whether ATRA can activate or inhibit MMPs in human dental pulp cells (HDPCs). The purpose of this study was to determine the effects of ATRA on the production and secretion of MMP-2 and -9 in HDPCs. The productions and messenger RNA (mRNA) expressions of MMP-2 and -9 were accessed by gelatin zymography and real-time polymerase chain reaction (PCR), respectively. ATRA was found to decrease MMP-2 level in a dose-dependent manner. Significant reduction in MMP-2 mRNA expression was also observed in HDPCs treated with 25 µmol⋅L−1 ATRA. However, HDPCs treated with ATRA had no effect on the pattern of MMP-9 produced or secreted in either cell extracts or conditioned medium fractions. Taken together, ATRA had an inhibitory effect on MMP-2 expression in HDPCs, which suggests that ATRA could be a candidate as a medicament which could control the inflammation of pulp tissue in vital pulp therapy and regenerative endodontics. A strategy for suppressing enzymes involved in inflammation could improve patient response to endodontic repair of damaged pulp tissue, report dental researchers in Korea. Direct pulp capping can preserve the health of an infected tooth, although tissue inflammation can undermine the efficacy of this intervention. Proteins known as matrix metalloproteinases (MMPs) contribute to inflammation in numerous different cell types including dental pulp. Sun-Young Kim and colleagues at Kyung Hee University identified a molecule that may limit MMPs’ effects. They found that all-trans retinoic acid (ATRA), a derivative of vitamin A, can reduce production of MMP-2 at non-toxic doses in cultured human dental pulp cells. Although ATRA did not inhibit production of MMP-9, another enzyme involved in pulp cell inflammation, follow-up experiments using inflamed as well as healthy pulp cells should help clarify ATRA’s anti-inflammatory effects.

Aim To determine whether chemokines such as SDF-1 and monocyte chemoattractant protein-1 (MCP-1) are responsible for hydrogen peroxide (H2O2)-induced extracellular matrix (ECM) degradation and to identify the underlying mechanism in human dental pulp cells (HDPCs). Method Human dental pulp cells were exposed to 0.4 mmol H2O2 for 48 h. mRNA expression and protein expression were examined by RT-PCR and Western blot analysis, respectively. The mRNA expression of chemokine (SDF-1 and MCP-1), their receptors (CXCR4 and CXCR2) and extracellular matrix proteins was evaluated by reverse transcriptase-polymerase chain reaction. The production of SDF-1, MCP-1, CXCR4 and CCR2 in the culture medium was determined by enzyme-linked immunosorbent assay. Signal transduction pathway was examined by Western blotting. Results Hydrogen peroxide provoked the activation of MCP-1 and SDF-1 mRNA and their respective receptors, CXCR4 and CXCR2. H2O2treatment concomitantly downregulated the expression of ECM molecules, such as type I collagen, elastin and fibronectin, and upregulated the mRNA expression of matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-8 and MMP-9. Hydrogen peroxide-induced ECM degradation and MMP upregulation were blocked by neutralizing antibodies and siRNAs directed against SDF-1 and MCP-1. Inhibition of SDF-1 and MCP-1 blocked the H2O2-induced activation of Akt, p38, ERK and NF-kB. Conclusion Inhibition of SDF and MCP-1 is a potent component of reducing release reactive oxygen species-induced ECM degradation in HDPCs and may play an important role in pulpal and periapical inflammation.

This study compared the dentin bond strength of a new universal adhesive with that of contemporary multi-step dentin adhesives. Six experimental groups were prepared according to the adhesives used and their application modes: Optibond FL (OB), Adper Single Bond Plus (SB), One-Step Plus (OS), Clearfil SE Bond (CS), All-Bond Universal using etch-and-rinse mode (ABE), and AllBond Universal using self-etch mode (ABS). Micro-tensile bond strength (µTBS) and failure mode were evaluated for each group. The bonded interface was analyzed using transmission electron microscopy (TEM). As a result, µTBS of 6 experimental groups was followed as: OB=ABE=SE=ABS>SB>OS group. TEM micrographs of ABE and ABS groups revealed a homogenous adhesive layer formation. In conclusion, a new universal adhesive can make reliable bond to dentin, regardless of the application mode.

The purpose of this study was to evaluate the effects of a GENESIS-BCP™ scaffold composed of hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) on bone formation. The relative ratio of components forming GENESIS-BCPTM was investigated by confirming the molar ratio of Ca/P through energy dispersive spectrometer (EDS) analysis. The results being that the scaffold is comprised of 60% HAp and 40% β-TCP. Moreover, scanning electron microscopy (SEM) images showed a unique surface morphology similar to a soccer ball. X-ray diffraction (XRD) analysis showed that the porosity, crystallinity, and Ca/P ratio were 65.5%, 84.9%, and 1.61%, respectively. In vitro tests including cytotoxicity and cell proliferation showed a good biocompatibility of GENESIS-BCP™. In vivo tests, including mouse skull test, and hematoxylin and eosin stains of GENESIS-BCP™ implanted in rabbit and human subjects showed that the bone graft is effective to accelerate new bone formation. It was concluded that GENESIS-BCP™ can be used as an effective alloplast bone graft.

Coenzyme Q10 (CoQ10), selenium, and curcumin are known to be powerful antioxidants. Osteoclasts are capable of resorbing mineralized bone and excessive bone resorption by osteoclasts causes bone loss-related diseases. During osteoclast differentiation, the reactive oxygen species (ROS) acts as a secondary messenger on signal pathways. In this study, we investigated whether antioxidants can inhibit RANKL-induced osteoclastogenesis through suppression of ROS generation and compared the relative inhibitory activities of CoQ10, sodium selenite, and curcumin on osteoclast differentiation. We found that antioxidants markedly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells in both bone marrow-derived monocytes (BMMs) and RAW 264.7 cells. Antioxidants scavenged intracellular ROS generation within osteoclast precursors during RANKL-stimulated osteoclastogenesis. These also acted to significantly suppress the gene expression of NFATc1, TRAP, and osteoclast-associated immunoglobulin-like receptor (OSCAR), which are genetic markers of osteoclast differentiation in a dose-dependent manner. These antioxidants also suppressed ROS-induced IκBα signaling pathways for osteoclastogenesis. Specially, curcumin displayed the highest inhibitory effect on osteoclast differentiation when concentrations were held constant. Together, CoQ10, selenite, and curcumin act as inhibitors of RANKL-induced NFATc1 which is a downstream event of NF-κB signal pathway through suppression of ROS generation, thereby suggesting their potential usefulness for the treatment of bone disease associated with excessive bone resorption.

Summary The purpose of this study was to compare the surface morphology and surface hardness of five materials 24 h after filling, in conditions of 100% humidity, and fetal bovine serum. The five materials were ProRoot Mineral Trioxide Aggregate (MTA), Super-EBA, Intermediate Restorative Materials (IRM), Zinc Oxide Eugenol (ZOE), and Amalgam. The microhardness of these materials was evaluated by Vickers microhardness test, and their morphologies were compared by using scanning electron microscopy (SEM). To evaluate the microhardness, the mixed five materials were measured with Vickers microhardness test. Differences between the experimental groups were analyzed by two-way ANOVA and Duncan's multiple comparison tests. All analyses were performed using the Statistical Package for the Social Sciences (SPSS Inc., Chicago, IL). For the microstructural morphological evaluation, the cross cut and root-end cavity prepared surfaces followed by retrograde filling with five different materials were observed under a Scanning Electron Microscope (Steroscan 440; Leica, Cambridge, England) at ×500. To summarize, Super EBA was less influenced by storage medium than the other materials, especially MTA. However, further long-term studies considering other factors, such as biocompatibility (i.e. cellular toxicity) and retention, are needed to be collaborated with these findings in the clinical context. SCANNING 34: 207-214, 2012. © 2011 Wiley Periodicals, Inc.

The management of complicated crown-root fractures is a challenge. Intentional replantation with 180° rotation may be a useful procedure to overcome this problem. In Case 1, a 23-year-old woman with complicated crown-root fractured teeth #11, #21, and #22 was referred for treatment. All fractured teeth were extracted, rotated 180°, and replanted in a slightly extruded position. After 3 months, root canal treatment was completed and the final restorations fabricated. At the 18-month follow up, the patient was asymptomatic, the tooth was functional, and no root resorption was observed radiographically. At the 90-month follow up, slight cervical root resorption of tooth #11 was noted. In Case 2, a 27-year-old woman with a crown-root fractured tooth #21 was referred for treatment. Despite immediate repositioning of the coronal fragment and a 2-week stabilization with a wire splint, the coronal fragment remained separated from the apical tooth segment. The apical segment was extracted, rotated 180°, and replanted in a slightly extruded position. After 1 and 4 weeks, the root canal treatment was completed and the final restoration fabricated, respectively. At the 24-month follow up, the patient was asymptomatic and apical healing was completed.

Chlorhexidine (CHX) has been reported to reduce self-degradation of collagen fibrils by inhibiting host-derived protease activity in demineralized dentin. Theoretically, if the collagen fibril scaffold of demineralized dentin maintains its original crosslinkage pattern on treatment with CHX and appropriate supplementation with necessary mineral sources, dentin remineralization may occur in demineralized lesions. In this study, we provide direct mechanical and micromorphological evidence for the ability of CHX to promote remineralization of demineralized dentin. Specifically, with respect to demineralized dentin blocks treated with different concentrations of CHX (0.02–2%) and stored in simulated body fluid, we have observed a significant increase in the elastic modulus of dentin treated with relatively high concentrations of CHX (0.2 and 2%) as storage time increased, whereas the elastic modulus of the non-CHX treated control group decreased. We have also observed a dense mineral deposition along collagen fibrils in the dentin group treated with 0.2 and 2% CHX via field emission scanning electron microscopy. SCANNING 34: 151–158, 2012. © 2011 Wiley Periodicals, Inc.

Objectives: The aim of this study was to evaluate the optical characteristics such as color and translucency changes before and after light curing, to quantify the CQ and to measure refractive indices of body and opaque shade of resin composites materials. Materials and Methods: Resin composites used in this study were A2 body and A2 opaque shade of EsthetX, Filtek supreme, Gradia Direct, Clearfil Majesty and BeautifilⅡ. Color and translucency changes before and after light curing were evaluated by colorimeter, the CQ was quantified by GC-MS and refractive index changes were measured by spectroscopic ellipsometer. Results: Translucency parameter (TP) was significantly increased after curing. The CQ content of body shades are higher than that of opaque shades in all resin composites. Refractive index increased after polymerization in all materials and significant difference in Δrefractive index was found between body and opaque shade (significance level 0.05). Conclusions: For an accurate shade match, direct shade matching of resin composite should be performed by using the cured material. [J Kor Acad Cons Dent 2011;36(3):219-230.]

The effect of the ethylenediaminetetraacetic acid (EDTA) treatment on the hybrid layer durability of total-etch dentin adhesives was investigated. A flat dentin surface was exposed and treated with 37% phosphoric acid or 0.1 M EDTA. Dentin adhesive was applied and a 4 mm thick composite resin was built-up. Twenty 0.9×0.9 mm(2) resin-dentin beams were fabricated in each experimental group. Artificial aging with 10% NaClO was performed in half of the experimental groups for 1 hour. A micro-tensile bond strength (µTBS) test was performed and the bonded interface was analyzed with transmission electron microscopy (TEM). The 37% phosphoric acid-treated group showed a lower µTBS after artificial aging, whereas the 0.1 M EDTA-treated group did not. TEM analysis revealed collagen fibrils dissolved in the 37% phosphoric acid-treated group but not in the 0.1M EDTA-treated group. Undissolved minerals were observed in the 0.1 M EDTA-treated group. In conclusion, a dentin treatment with 0.1M EDTA is effective in improving the hybrid layer durability.

Purpose: This study investigated the effect of accumulated dose on radiophotoluminescent glass dosimeter in megavoltage photon. Methods: 45 commercially-available radio-photoluminescence glass dosimeters (RPLGD; GD-302M, Asahi Techno Glass Co., Shizuoka, JAPAN) were irradiated to 10 × 10 cm2 open-field with 6, 10 and 15 MV photon beams at 100 cm of source to surface distance and dose maximum depths. Each energy has consists of five groups which is consists of three detectors. A group #1 and #2 was irradiated about 1 Gy to 100 Gy, and estimated the integral dose response with and without annealing procedure. A group #3 was read the dose after irradiated 10 Gy of dose by 10 times repeatedly to estimate the fading effect of RPLGD. A group #4 and #5 was produced same ways with different irradiation dose such as 50 Gy for group #4 and 100 Gy for group #5. Results: From the results of group #1 and #2, an annealed detector shows linear response to integral dose but other detectors without the annealing process, has supra linearity for integral dose especially close to 100 Gy dose. For group #3, #4 and #5, the dose response of repeated irradiation, the dose response was decreased about 15%, 12% and 7% for 6 MV, 10 MV and 15MV. Conclusion: It was found that RPLGD response to accumulated dose was supra linear and this respond was altered with amount of accumulated dose to the RPLGD. In addition, the fading effect need to be concern with RPLGD.

Aim To evaluate the anti-inflammatory effects of glutamine and the underlying signal pathway mechanisms in lipopolysaccharide (LPS)-stimulated human dental pulp cells (HDPCs). Methods Human dental pulp cells were exposed to 10 μg mL−1 LPS and various concentrations of glutamine for 24 h. The production of PGE2 and nitric oxide was determined by enzyme-linked immunosorbent assay (ELISA) and Griess reagent kit, respectively. Cytokines were examined by ELISA, reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR. iNOS and COX protein expression as well as signal pathways were accessed by Western blot. The data were analysed by anova with Bonferroni's test (α = 0.05). Results Glutamine reduced LPS-induced iNOS and COX-2 protein expression as well as production of NO and PGE2 in a dose-dependent fashion. Additionally, glutamine suppressed the production and mRNA expression of inflammatory cytokines including interleukin-1β (IL-1β), TNF-α, and IL-8. Furthermore, glutamine attenuated phosphorylation of extracellular signal-regulated kinase (ERK), p38, c-Jun N-terminal kinase (JNK) and IκB-α, and nuclear translocation of NF-kB p65, but enhanced mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in LPS-treated HDPCs. Conclusion Glutamine exerted an anti-inflammatory effect via activation of MKP-1 and inhibition of the NF-kB and MAPK pathways in LPS-treated HDPCs.

Introduction Although glutamine (Gln) is mitogenic in various cell types, little is known about its role in human dental pulp cells (HDPCs). This study investigated the effects of Gln on proliferation, migration, and odontoblastic differentiation of HDPCs and the underlying signal pathway mechanisms. Methods Growth and migration were assessed by cell counting and colorimetric cell migration kits. Differentiation was measured as alkaline phosphatase activity, calcified nodule formation by alizarin red staining, and marker mRNA expression by reverse transcriptase–polymerase chain reaction (RT-PCR). Chemokine expression was also evaluated by RT-PCR. Signal transduction pathways were examined by RT-PCR and Western blot analysis. Results Gln dose-dependently increased proliferation, migration, alkaline phosphatase activity, mineralized nodule formation, and odontoblast-marker mRNA of HDPCs. Gln also up-regulated expression of interleukin-6, interleukin-8, MCP-1, MIP-3α, CCL2, CCL20, and CXCL1. Gln increased BMP-2 and BMP-4 mRNA, phosphorylation of Smad 1/5/8, β-catenin, and key proteins of the Wnt signaling pathway. Furthermore, Gln resulted in up-regulation of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase. In addition, noggin, DKK1, inhibitors of p38, ERK, and JNK significantly attenuatted Gln-induced growth, migration, and odontoblastic differentiation. Conclusions Collectively, this study demonstrated that Gln promoted growth, migration, and differentiation in HDPCs through the BMP-2, Wnt, and MAPK pathways, leading to improved pulp repair and regeneration.

Aim To examine the role of stromal cell–derived factor 1 (SDF-1) signalling during odontogenic differentiation in human dental pulp cells (HDPCs). Methodology Human dental pulp cells were treated with differentiation medium, recombinant human SDF-1, neutralizing antibody for SDF-1 or CXCR4, pertussis toxin (PTX) and AMD3100. The expression of SDF-1 and its receptor chemokine receptor type 4 (CXCR4) was measured by reverse transcription–polymerase chain reaction (RT-PCR) and Western blotting. Odontoblastic differentiation was determined using alkaline phosphatase (ALP) activity assay, mineralized nodule formation and marker mRNAs by RT-PCR. Results Marked upregulation of SDF-1 and CXCR4 mRNA and protein was observed in cells grown 7 days in osteogenic induction medium. The addition of recombinant human SDF-1 to HDPCs significantly (P

With conventional fixed dental prostheses, the interim restoration is a valuable diagnostic tool in the evaluation of esthetics and function. To achieve predictable definitive esthetic results, information about the subgingival and the supragingival contour of a properly designed restoration should be communicated to the dental laboratory technician. The technique described enables the accurate transfer of the soft tissue morphology developed with an interim prosthesis to the definitive cast. This modified definitive cast allows the dental laboratory technician to fabricate a restoration with an emergence profile identical to that of the interim prosthesis.

Aluminum/Copper clad sheet has been fabricated using asymmetric extrusion method, which caused severe shear deformation between Al and Cu plate to easily bond to each other. Interfacial microstructure and mechanical properties of Al/Cu clad were studied by scanning electron microscope equipped with energy dispersive X-ray detector, micro-hardness, and tension tests. The asymmetric extrusion bonding was very effective to provide a good interface for atoms diffusion during subsequent annealing. The strength of bonding was higher with the increasing extrusion ratio., {"references":["H. D. Manesh, and A. K. Taheri, J. Alloys Compd., vol. 361, pp. 138-143,\n2003.","K. Y. Rhee, W.Y. Han, H. J. Park, and S. S. Kim, Mater. Sci. Eng. A, vol.\n384, pp. 70-76, 2004.","R.Jamaati, and M. R. Toroghinejad,Mater.Des.,vol. 31, pp. 4508-4513,\n2010.","L. Li, N. Nagaiand F. X. Yin,Sci. Tech. Adv. Mater.,vol. 9, pp. 1-11,\n2008.","N. Bay, C. Clemensen, O. Juelstorp and T. Wanheim,CIRP Ann. Manuf.\nTech., vol. 34, pp. 221-224, 1985.","D. L. Sponseller, G. A. Timmons, and W. T. Bakker, J. Mater. Eng., vol. 7,\np. 227, 1998.","J. D. Dobis, and B. Chakravarti,Mater. Perform.,vol. 36, p. 29, 1997.","T. Ieda, and Y. Tanaka,J. Jpn. Soc. Tech. Plasticity, vol. 23, p. 965, 1982.","W. Zhang, and N. Bay, Weld. J., vol. 76, pp. s326-s330, 1997.\n[10] M. Eizadjou, H. D. Manesh, and K. Janghorban, Mater. Des., vol. 30, pp.\n4156-4161, 2009.\n[11] G. P. Zhang, H. S. Liu, and B. Zhang, Scr. Mater., vol. 64, pp. 13-16,\n2011."]}

We recently reported that overexpression of thymosin beta-4 (Tβ4) in transgenic mice promotes abnormal hair growth and tooth development, but the role of Tβ4 in dental pulp regeneration was not completely understood. The aim of this study was to investigate the role of Tβ4 on odontoblastic differentiation and the underlying mechanism regulating pulp regeneration in human dental pulp cells (HDPCs). Our results demonstrate that mRNA and protein expression of Tβ4 is upregulated during odontogenic differentiation in HDPCs. Transfection with Tβ4 siRNA decreases OM-induced odontoblastic differentiation by decreasing alkaline phosphatase (ALP) activity, mRNA expression of differentiation markers, and calcium nodule formation. In contrast, Tβ4 activation with a Tβ4 peptide promotes these processes by enhancing the phosphorylation of p38, JNK, and ERK mitogen-activated protein kinases (MAPKs), bone morphogenetic protein (BMP) 2, BMP4, phosphorylation of Smad1/5/8 and Smad2/3, and expression of transcriptional factors such as Runx2 and Osterix, which were blocked by the BMP inhibitor noggin. The expression of integrin receptors α1, α2, α3, and β1 and downstream signaling molecules including phosphorylated focal adhesion kinase (p-FAK), p-paxillin, and integrin-linked kinase (ILK) were increased by Tβ4 peptide in HDPCs. ILK siRNA blocked Tβ4-induced odontoblastic differentiation and activation of the BMP and MAPK transcription factor pathways in HDPCs. In conclusion, this study demonstrates for the first time that Tβ4 plays a key role in odontoblastic differentiation of HDPCs and activation of Tβ4 could provide a novel mechanism for regenerative endodontics.

Purpose: To evaluate the reliability of RPN (Risk Priority Number) decided by expert group and to provide preliminary data for adapting FMEA in Korea. Methods: 1163 Incidents reported in ROSIS for 11 years were used as a real data to be compared with, and were categorized into 146 items. The questionnaire was composed of the 146 items and respondents had to valuate ‘occurrence (O)’, ‘severity (S)’, ‘detectability (D)’ of each item on a scale from 1 to 10 according to the proposed AAPM TG-100 rating scales. 19 medical physicists from 19 different organizations in Korea had participated in the survey. Because the number of ROSIS items was not evenly spread enough to be classified into 10 grades, 1–5 scale was chosen instead of 1–10 and survey result was also fit to 5 grades to compare. Results: The average O,S,D were 1.77, 3.50, 2.13, respectively and the item which had the highest RPN(32) was ‘patient movement during treatment’ in the survey. When comparing items ranked in the top 10 of each survey(O) and ROSIS database, two items were duplicated and ‘Simulation’ and 'Treatment’ were the most frequently ranked RT process in top 10 of survey and ROSIS each. The Chronbach α of each RT process were ranged from 0.74 to 0.99 and p-value was

Purpose: Confirming the dose delivered to a patient is important to make sure the treatment quality and safety of the radiotherapy. Measuring a transit dose of the patient during the radiotherapy could be an interesting way to confirm the patient dose. In this study, we evaluated the feasibility of the transit dosimetry with a glass dosimeter in brachytherapy. Methods: We made a phantom that inserted the glass dosimeters and placed under patient lying on a couch for cervix cancer brachytherapy. The 18 glass dosimeters were placed in the phantom arranged 6 per row. A point putting 1cm vertically from the source was prescribed as 500.00 cGy. Solid phantoms of 0, 2, 4, 6, 8, 10 cm were placed between the source and the glass dosimeter. The transit dose was measured each thickness using the glass dosimeters and compared with a treatment planning system (TPS). Results: When the transit dose was smaller than 10 cGy, the average of the differences between measured values and calculated values by TPS was 0.50 cGy and the standard deviation was 0.69 cGy. If the transit dose was smaller than 100 cGy, the average of the error was 1.67 ± 4.01 cGy. The error to a point near the prescription point was −14.02 cGy per 500.00 cGy of the prescription dose. Conclusion: The distances from the sources to skin of the patient generally are within 10 cm for cervix cancer cases in brachytherapy. The results of this preliminary study showed the probability of the glass dosimeter as the transit dosimeter in brachytherapy.