A comparison of osteogenic effect of newly manufactured calcium silicate-based sealers in vitro.

This study aimed to assess the effect of different calcium silicate-based root canal sealers (CSRS) on osteogenic effect in human periodontal ligament cells (hPDLCs). hPDLCs were cultured in a medium containing extract of 5 types of CSRS. The specimens were assessed by the cell cytotoxicity test, alkaline phosphatase staining, alizarin red S staining, quantitative real-time PCR, Western blot analysis, and enzyme-linked immunosorbent assay. The diluted concentrations of extracted solutions had no significant effect on the viability of hPDLCs. There was a statistically significant difference in the mRNA expression level of bone sialoprotein (BSP), osteocalcin (OCN), and runt-related transcription factor 2 (RUNX2) among some groups. The protein expressions of BSP, OCN, and RUNX2 were significantly higher in some groups compared to the control group. The CSRS did not interfere with the osteogenic differentiation of hPDLCs, compared to the control group. CSRS are shown to have biocompatibility and osteogenic differentiation effect on hPDLCs.

Effect of Leptin on Odontoblastic Differentiation and Angiogenesis: An In Vivo Study.

INTRODUCTION: Leptin is secreted as a peptide hormone from adipose tissues. The aim of this study was to evaluate the effects of leptin on reparative dentin formation and angiogenesis in the pulp tissue of teeth in vivo. METHODS: Twenty-four 7-week-old male rats were anesthetized. Cavities were prepared in maxillary first molars. Pulp cappings were performed with collagen scaffold (Col) with a phosphate-buffered saline (PBS) vehicle (Col + PBS), leptin 1 µmol/L with Col (L1 + Col), or leptin 10 µmol/L with Col (L10 + Col). For the negative control group (no pulp capping), pulp capping was not performed. All cavities were sealed with resin-modified glass ionomer followed by a micro-computed tomographic scan, histologic examination, and immunohistochemical analysis. RESULTS: The volume of newly formed mineralized tissue in the leptin group was significantly (P < .01) higher than that in the control group based on micro-computed tomographic analysis. In histologic examination, hard tissue formation was rarely shown in the no pulp capping and Col + PBS groups. However, significantly (P < .01) larger amounts of newly mineralized tissue deposition were observed in the leptin groups. In immunohistochemical analysis, reparative dentin and new vessels formed in the pulp cavity of the leptin groups. Vascular endothelial growth factor, dentin sialoprotein, and dentin sialophosphoprotein were expressed around the newly formed mineralized tissue area. CONCLUSIONS: Leptin showed the ability to induce angiogenesis, odontogenic differentiation, and mineralization in exposed rat pulps. Leptin also exhibited favorable inflammatory responses in the pulp tissue. Not only osteodentin but also tubular dentin and new vessels were observed in the pulp cavity.

Oral manifestation and root canal therapy of the patient with mucopolysaccharidosis.

Mucopolysaccharidosis (MPS) is an inherited metabolic disorder caused by a deficiency in enzymes that participate in the degradation of glycosaminoglycans (GAGs) such as heparin sulfate and dermatan sulfate. Left untreated, patients show progressive mental and physical deterioration due to deposition of GAGs in organs. Death often occurs due to cardiac or respiratory failure before patients reach their early twenties. MPS has several oral and dental manifestations. An enlarged head, short neck, and open mouth associated with a large tongue are major characteristics of MPS patients. Dental complications can be severe, including unerupted dentition, dentigerous cyst-like follicles, malocclusions, condylar defects, and gingival hyperplasia. A 21-year-old female patient with MPS was described in this article, with special emphasis on oral manifestations and dental treatment.

Anti-inflammatory and Osteogenic Effects of Calcium Silicate-based Root Canal Sealers.

INTRODUCTION: An ideal root canal sealer creates a bacteria-resistant seal and exhibits antimicrobial activity, biocompatibility, and osteoconductivity. The aim of this study was to assess the effects of 3 root canal sealers on cell viability, inflammatory response, and osteogenic potential in MC3T3-E1 cells. METHODS: AH Plus (Dentsply Caulk, Milford, DE), MTA Fillapex (Angelus Solucxoes Odontologicas, Londrina, Brazil), and EndoSequence BC (Brasseler, Savannah, GA) were mixed according to the manufacturer's instructions, and samples were prepared as extraction media (final dilution: 1/10). Lipopolysaccharide (LPS) (100 ng/mL) treatment was used to induce an inflammatory response in this study. Cell viability was evaluated using the Water soluble tetrazolium-1 (WST-1) assay. The levels of inflammatory mediators (interleukin 6 and tumor necrosis factor alpha) and osteogenic marker genes (ALP and OCN) were measured by reverse-transcription polymerase chain reaction and real-time polymerase chain reaction. Osteogenic potential was evaluated by alkaline phosphatase staining and alizarin red staining. RESULTS: Calcium silicate-based sealers such as MTA Fillapex and EndoSequence BC showed strong cell viability compared with AH Plus. AH Plus, MTA Fillapex, and EndoSequence BC decreased the levels of LPS-induced inflammatory mediators (P < .05). The expression of osteogenic marker genes, alkaline phosphatase activity, and mineralized nodule formation decreased with LPS treatment. However, AH Plus and calcium silicate-based sealers increased the osteogenic potential reduced by LPS treatment (P < .05). CONCLUSIONS: Calcium silicate-based sealers exhibit anti-inflammatory effects and induce osteogenic differentiation in MC3T3-E1 cells.

Anti-inflammatory and Mineralization Effects of ProRoot MTA and Endocem MTA in Studies of Human and Rat Dental Pulps In Vitro and In Vivo.

INTRODUCTION: Few studies have reported direct pulp capping in inflamed pulp conditions. The purpose of this study was to investigate the in vitro and in vivo responses of dental pulp during direct pulp capping using various pulp capping materials in inflamed conditions. METHODS: Human dental pulp cells were treated with lipopolysaccharide (LPS) and cultured with Dycal (Dentsply Caulk, Milford, DE), ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland), and Endocem MTA (Maruchi, Wonju, South Korea). The expressions of interleukin (IL)-1ß, IL-6, dentin matrix protein 1, and dentin sialophosphoprotein were analyzed through real-time polymerase chain reaction. The maxillary molars of Sprague-Dawley rats were exposed for 2 days. The exposed pulps were capped with Dycal, ProRoot MTA, and Endocem MTA and sealed with resin-modified glass ionomer followed by histologic and immunohistochemical analyses. RESULTS: The expression of IL-1ß and IL-6 was increased with LPS and decreased by Dycal, ProRoot MTA, and Endocem MTA. Dentin matrix protein 1 and dentin sialophosphoprotein levels were decreased with LPS and increased after treatment with pulp capping materials.In the in vivo study, inflammation associated with Dycal was higher than that associated with ProRoot MTA and Endocem MTA at week 1, without any significant difference between the 2. At 4 weeks, inflammation was decreased, and mineralization was increased compared with week 1 in all 3 of the materials. At week 1, IL-6 immunoreactivity was strongly expressed. Dycal exhibited stronger immunoreactivity than ProRoot MTA and Endocem MTA. However, the immunoreactivity was decreased in all groups at week 4. CONCLUSIONS: Successful direct pulp capping requires more effective pulp capping materials for the treatment of inflamed pulps.

Physical properties and biological effects of mineral trioxide aggregate mixed with methylcellulose and calcium chloride

Abstract Objectives: Methylcellulose (MC) is a chemical compound derived from cellulose. MTA mixed with MC reduces setting time and increases plasticity. This study assessed the influence of MC as an anti-washout ingredient and CaCl2 as a setting time accelerator on the physical and biological properties of MTA. Material and Methods: Test materials were divided into 3 groups; Group 1(control): distilled water; Group 2: 1% MC/CaCl2; Group 3: 2% MC/CaCl2. Compressive strength, pH, flowability and cell viability were tested. The gene expression of bone sialoprotein (BSP) was detected by RT-PCR and real­ time PCR. The expression of alkaline phosphatase (ALP) and mineralization behavior were evaluated using an ALP staining and an alizarin red staining. Results: Compressive strength, pH, and cell viability of MTA mixed with MC/CaCl2 were not significantly different compared to the control group. The flowability of MTA with MC/CaCI2 has decreased significantly when compared to the control (p<.05). The mRNA level of BSP has increased significantly in MTA with MC/CaCl2 compared to the control (p<.05). This study revealed higher expression of ALP and mineralization in cells exposed to MTA mixed with water and MTA mixed with MC/CaCl2 compared to the control (p<.05). Conclusions: MC decreased the flowability of MTA and did not interrupt the physical and biological effect of MTA. It suggests that these cements may be useful as a root-end filling material.

Effects of 3 endodontic bioactive cements on osteogenic differentiation in mesenchymal stem cells.

INTRODUCTION: Because a root-end filling material comes into contact with the surrounding cells or tissues, understanding the cell-material interfacial activity is important. Thus, the purpose of this study was to assess the biocompatibility of 3 endodontic bioactive cements (MTA [Dentsply, Tulsa, OK], Bioaggregate [BA; Innovative Bioceramix, Vancouver, BC, Canada], and Biodentine [BD; Septodont, St Maur des Fosses, France]) and to investigate the effect of cements on the differentiation of mesenchymal stem cells. METHODS: Cell viability, mineralization, and differentiation were evaluated using an 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) assay and alkaline phosphatase (ALP) staining. The expressions of ALP, osteocalcin, and bone sialoprotein at the gene level were detected by reverse-transcription polymerase chain reaction and real-time polymerase chain reaction. RESULTS: Cell viability of BD in concentrations of 1, 1/2, and 1/4 was significantly lower than MTA and BA (P < .05). There was no statistically significant difference in cell viability between materials in concentrations of 1/10 and 1/50 (P < .05). The messenger RNA level of osteogenic genes increased significantly in the MTA and BA groups compared with controls (P < .05). However, although the messenger RNA level of osteogenic genes increased in the BD group, there was no statistically significant difference compared with controls. MTA, BA, and BD led to an increase in ALP staining compared with controls. CONCLUSIONS: In conclusion, MTA, BA, and BD have effects on osteoblast differentiation in mesenchymal stem cells, suggesting that these cements may be useful for root-end filling material.

Glycol chitin-based thermoresponsive hydrogel scaffold supplemented with enamel matrix derivative promotes odontogenic differentiation of human dental pulp cells.

INTRODUCTION: Hydrogels have been widely studied as tissue engineering scaffolds over the past 2 decades because of their favorable biological properties. Recently, a new biodegradable glycol chitin-based thermoresponsive hydrogel scaffold (GC-TRS) was developed that can be easily applied as a mild viscous solution at room temperature but quickly transforms into a durable hydrogel under physiological conditions. The aim of this study was to investigate the effects of GC-TRS on the proliferation and odontogenic differentiation of colony-forming human dental pulp cells (hDPCs) in the presence of enamel matrix derivative. METHODS: Glycol chitin was synthesized by N-acetylation of glycol chitosan. The morphology of the thermoresponsive hydrogel scaffold was observed by using scanning electron microscopy. The sol gel phase transition of the aqueous solution of glycol chitin was investigated by using the tilting method and rheometer studies. hDPCs were isolated based on their ability to generate clonogenic adherent cell clusters. The effect of GC-TRS and collagen on cell viability was examined by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of markers for odontogenic/osteogenic differentiation (ie, dentin sialophosphoprotein, dentin matrix protein-1, osteonectin, and osteopontin) was analyzed by performing real-time polymerase chain reaction. RESULTS: GC-TRS exhibited a highly macroporous and well-interconnected porous structure. The polymer solution existed in a mildly viscous sol state, but it transitioned to a gel state and did not flow above approximately 37°C. Rheometer studies showed that the glycol chitin solution exhibited a fast sol gel transition approximately at body temperature. GC-TRS and collagen did not inhibit cell viability until 7 days. Dentin sialophosphoprotein and dentin matrix protein-1 were expressed by cells cultured in GC-TRS at a higher level than that in cells cultured in collagen (P < .05). In both the scaffold groups, dentin sialophosphoprotein, dentin matrix protein-1, and osteopontin messenger RNA was up-regulated significantly in EMD-treated hDPCs when compared with the nontreated cells (P < .05). CONCLUSIONS: GC-TRS allowed the proliferation and odontogenic differentiation of hDPCs. Furthermore, the differentiation was facilitated by EMD. These results suggest that GC-TRS has the potential to be used in tissue engineering techniques for dentin regeneration.

Thermal analysis of bulk filled composite resin polymerization using various light curing modes according to the curing depth and approximation to the cavity wall

OBJECTIVE: The purpose of this study was to investigate the polymerization temperature of a bulk filled composite resin light-activated with various light curing modes using infrared thermography according to the curing depth and approximation to the cavity wall. MATERIAL AND METHODS: Composite resin (AeliteFlo, Bisco, Schaumburg, IL, USA) was inserted into a Class II cavity prepared in the Teflon blocks and was cured with a LED light curing unit (Dr's Light, GoodDoctors Co., Seoul, Korea) using various light curing modes for 20 s. Polymerization temperature was measured with an infrared thermographic camera (Thermovision 900 SW/TE, Agema Infra-red Systems AB, Danderyd, Sweden) for 40 s at measurement spots adjacent to the cavity wall and in the middle of the cavity from the surface to a 4 mm depth. Data were analyzed according to the light curing modes with one-way ANOVA, and according to curing depth and approximation to the cavity wall with two-way ANOVA. RESULTS: The peak polymerization temperature of the composite resin was not affected by the light curing modes. According to the curing depth, the peak polymerization temperature at the depth of 1 mm to 3 mm was significantly higher than that at the depth of 4 mm, and on the surface. The peak polymerization temperature of the spots in the middle of the cavity was higher than that measured in spots adjacent to the cavity wall. CONCLUSION: In the photopolymerization of the composite resin, the temperature was higher in the middle of the cavity compared to the outer surface or at the internal walls of the prepared cavity. .

Cytotoxicity of newly developed ortho MTA root-end filling materials.

INTRODUCTION: Various materials have been advocated for use as root-end filling materials. The purpose of the present in vitro study was to compare the cytotoxicity of 4 root-end filling materials: glass ionomer cement (GIC; Fuji II, GC Corp, Tokyo, Japan), reinforced zinc oxide-eugenol cement (IRM; Dentsply Tulsa Dental, Tulsa, OK), and 2 types of mineral trioxide aggregate. METHODS: This study used MG-63 cells derived from a human osteosarcoma. To quantitatively evaluate the cytotoxicity of test materials, the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay was used. The cells were exposed to the extracts and incubated. Cell viability was recorded by measuring the optical density of each test well in reference to controls. Each specimen was examined by scanning electron microscopy for the observation of cell morphology. RESULTS: The XTT assay showed that the cell viability of ProRoot MTA (Dentsply Tulsa Dental) was higher than that of GIC and Ortho MTA (BioMTA, Seoul, Republic of Korea) at all time points. IRM showed significantly lower cell viability than the other groups. The scanning electron microscopic analysis revealed that elongated, dense, and almost confluent cells were observed in the cultures of GIC, Ortho MTA, and ProRoot MTA specimens. In contrast, cells on the surface of IRM were rounded in shape, and the numbers and the density of the cells were smaller than that in the other groups. CONCLUSIONS: ProRoot MTA and GIC showed good biocompatibility in this study. However, Ortho MTA showed lower biocompatibility compared with ProRoot MTA and GIC.

Effect of a multi-layer infection control barrier on the micro-hardness of a composite resin

OBJECTIVE: The aim of this study was to evaluate the effect of multiple layers of an infection control barrier on the micro-hardness of a composite resin. MATERIAL AND METHODS: One, two, four, and eight layers of an infection control barrier were used to cover the light guides of a high-power light emitting diode (LeD) light curing unit (LCU) and a low-power halogen LCU. The composite specimens were photopolymerized with the LCUs and the barriers, and the micro-hardness of the upper and lower surfaces was measured (n=10). The hardness ratio was calculated by dividing the bottom surface hardness of the experimental groups by the irradiated surface hardness of the control groups. The data was analyzed by two-way ANOVA and Tukey's HSD test. RESULTS: The micro-hardness of the composite specimens photopolymerized with the LED LCU decreased significantly in the four- and eight-layer groups of the upper surface and in the two-, four-, and eight-layer groups of the lower surface. The hardness ratio of the composite specimens was <80% in the eight-layer group. The micro-hardness of the composite specimens photopolymerized with the halogen LCU decreased significantly in the eight-layer group of the upper surface and in the two-, four-, and eight-layer groups of the lower surface. However, the hardness ratios of all the composite specimens photopolymerized with barriers were <80%. CONCLUSIONS: The two-layer infection control barrier could be used on high-power LCUs without decreasing the surface hardness of the composite resin. However, when using an infection control barrier on the low-power LCUs, attention should be paid so as not to sacrifice the polymerization efficiency.

Effect of laser irradiation on crystalline structure of enamel surface during whitening treatment with hydrogen peroxide.

OBJECTIVE: This study is to evaluate the effect of laser activation on the whitening and crystalline structure of enamel surface during whitening treatment with hydrogen peroxide. METHODS: Bovine teeth were treated with whitening gel containing 35% hydrogen peroxide. A whitening gel was applied on the enamel surface for a period of 5 min, and then irradiated using a diode laser (740 nm) during whitening treatment for 0, 30, 60, 120 and 180s for the GL0-W, GL30-W, GL60-W, GL120-W and GL180-W groups, respectively. The total whitening application time was 30 min for all groups. RESULTS: Laser-irradiated enamel groups showed a similar lightness compared to the GL0-W group. The thickness of porous layer observed on the enamel surface of GL0-W group was decreased by increasing the laser irradiation time. While the Ca and P contents of the GL0-W group were lower than those of the non-whitening treated group (GL0-C), the Ca and P contents of the GL180-W group were similar to those of the GL180-C group. The enamel crystallinity was dramatically decreased by whitening treatment without laser irradiation. However, the decrease of crystallinity was protected by laser irradiation during whitening treatment. Raman measurement verified that laser irradiation could prevent the loss of mineral compositions on enamel and maintain its crystalline structure. SIGNIFICANCE: The professional whitening treatment with hydrogen peroxide and diode laser activation improves not only the whitening effect but also protects the change of enamel structure compared to the treatment with only gel.

Chemical constitution, physical properties, and biocompatibility of experimentally manufactured Portland cement.

INTRODUCTION: An experimental Portland cement was manufactured with pure raw materials under controlled laboratory conditions. The aim of this study was to compare the chemical constitution, physical properties, and biocompatibility of experimentally manufactured Portland cement with those of mineral trioxide aggregate (MTA) and Portland cement. METHODS: The composition of the cements was determined by scanning electron microscopy (SEM) and energy-dispersive x-ray analysis (EDAX). The setting time and compressive strength were tested. The biocompatibility was evaluated by using SEM and XTT assay. RESULTS: SEM and EDAX revealed the experimental Portland cement to have a similar composition to Portland cement. The setting time of the experimental Portland cement was significantly shorter than that of MTA and Portland cement. The compressive strength of the experimental Portland cement was lower than that of MTA and Portland cement. The experimental Portland cement showed a similar biocompatibility to MTA. CONCLUSIONS: The experimental Portland cement might be considered as a possible substitute for MTA in clinical usage after further testing.

Chemical composition, radiopacity, and biocompatibility of Portland cement with bismuth oxide.

OBJECTIVE: This study compared the chemical constitution, radiopacity, and biocompatibility of Portland cement containing bismuth oxide (experimental cement) with those of Portland cement and mineral trioxide aggregate (MTA). STUDY DESIGN: The chemical constitution of materials was determined by scanning electron microscopy and energy-dispersive X-ray analysis. The radiopacity of the materials was determined using the ISO/6876 method. The biocompatibility of the materials was tested by MTT assay and tissue reaction. RESULTS: The constitution of all materials was similar. However, the Portland cement and experimental cement were more irregular and had a larger particle size than MTA. The radiopacity of the experimental cement was similar to MTA. The MTT assay revealed MTA to have slightly higher cell viability than the other materials. However, there were no statistically significant differences between the materials, with the exception of MTA at 24 h. There was no significant difference in the tissue reaction between the experimental groups. CONCLUSIONS: These results suggest that the experimental cement may be used as a substitute for MTA.