Saving an Integrating Implant Involved with Endodontic Implant Pathology Using Surgical Treatment.

Endodontic implant pathology (EIP) refers to cases in which endodontic infections cause infections in adjacent implants, and vice versa. This case report demonstrates the successful resolution of two types of EIPs, implant endodontitis and endodontic implantitis, by endodontic intervention with surgical treatment. In case 1, the patient complained of tooth discomfort after implant placement in the adjacent tooth. The tooth was sensitive to percussion and showed slight mobility with a negative reaction to an electric pulp test. The symptoms persisted despite conventional root canal treatment, and surgical treatment of the symptomatic tooth and implant lesion was performed. In case 2, the patient suffered from repeated infection around a newly installed implant. The adjacent devitalized tooth exhibited a periapical lesion that was contiguous with the implant. Conventional root canal treatment and retreatment did not successfully resolve the symptoms. Surgical root canal therapy was then performed with regenerative biomaterials as needed. Neither case showed radiographic or clinical evidence of failure after 4 and 5 years of follow-up, respectively, after the surgery and the adjacent implants were successfully osseointegrated. Endodontic intervention combined with surgical treatment resolved both types of EIPs and led to tooth preservation and successful osseointegration of adjacent implants.

Comparison of the rheological properties of four root canal sealers.

The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method (ISO 6876), and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer (Capseal) and three commercial root canal sealers (AH Plus, Sealapex and Pulp Canal Sealer EWT) were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method (n=5) and their viscosities were measured using a strain-controlled rheometer (n=5). The correlation between these two values was statistically analysed using Spearman's correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated (ρ=-0.8618). The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order: AH Plus

Mechanical properties and microstructure analysis of mineral trioxide aggregate mixed with hydrophilic synthetic polymer.

INTRODUCTION: In dentistry, mineral trioxide aggregate (MTA) has been widely used for root perforation, retrograde filling, pulp capping and regenerative endodontics. Despite its superior sealing ability and biocompatibility, MTA has critical drawbacks regarding handling property such as sandy property, lacking cohesive properties and wash-out tendency. So, it is necessary to improve the fluidity of MTA in order to improve its handling properties. In this study, we applied modified liquid to improve handling properties of MTA. METHODS: Polyvinyl alcohol (PVA; 3 and 5 wt %) aqueous solutions were prepared and the samples were divided into three groups: DW group (MTA mixed with distilled water), P3 group (MTA mixed with 3% PVA), and P5 group (MTA mixed with 5% PVA). Handling property, initial setting time, and compressive strength were evaluated. The microstructures were observed by Field emission scanning electron microscope (FE-SEM) and X-ray diffractometer (XRD) phase analyses were performed. RESULTS: PVA modified group showed similar behavior of IRM compared to DW group. The initial setting time of P3 or P5 group was significantly longer than that of DW group (p < 0.05). The compressive strength of DW group was higher than that of P3 or P5 groups (p < 0.05). Experimental groups (P3 and P5) showed no microstructural differences compared with DW group when the fractured surfaces were observed by FE-SEM with XRD patterns after 3 and 14 days. CONCLUSIONS: Polyvinyl alcohol, a modified liquid for MTA, improved the handling properties of the material without violating its microstructure.

Shaping ability of the conventional nickel-titanium and reciprocating nickel-titanium file systems: a comparative study using micro-computed tomography.

INTRODUCTION: This study used micro-computed tomographic imaging to compare the shaping ability of Mtwo (VDW, Munich, Germany), a conventional nickel-titanium file system, and Reciproc (VDW), a reciprocating file system morphologically similar to Mtwo. METHODS: Root canal shaping was performed on the mesiobuccal and distobuccal canals of extracted maxillary molars. In the RR group (n = 15), Reciproc was used in a reciprocating motion (150° counterclockwise/30° clockwise, 300 rpm); in the MR group, Mtwo was used in a reciprocating motion (150° clockwise/30° counterclockwise, 300 rpm); and in the MC group, Mtwo was used in a continuous rotating motion (300 rpm). Micro-computed tomographic images taken before and after canal shaping were used to analyze canal volume change and the degree of transportation at the cervical, middle, and apical levels. The time required for canal shaping was recorded. Afterward, each file was analyzed using scanning electron microscopy. RESULTS: No statistically significant differences were found among the 3 groups in the time for canal shaping or canal volume change (P > .05). Transportation values of the RR and MR groups were not significantly different at any level. However, the transportation value of the MC group was significantly higher than both the RR and MR groups at the cervical and apical levels (P < .05). In the scanning electron microscopic analysis, file deformation was observed for 1 file in group RR (1/15), 3 files in group MR (3/15), and 5 files in group MC (5/15). CONCLUSIONS: In terms of shaping ability, Mtwo used in a reciprocating motion was not significantly different from the Reciproc system.

Antibacterial efficacy of a human ß-defensin-3 peptide on multispecies biofilms.

INTRODUCTION: The aggregation of mixed bacterial flora into sessile biofilms on root canal surfaces can be one of the causes of persistent apical periodontitis. The aim of this study was to evaluate the antibacterial efficacy of human ß-defensin-3 (HBD3) peptide on multispecies biofilms by using confocal laser scanning microscopy. METHODS: Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans, and Enterococcus faecalis were cultured in a peptone-yeast-glucose broth, and their culture suspensions were combined in equal proportions. The mixed bacteria were inoculated on sterile coverslips placed into the wells of tissue culture plates to permit the formation of mixed species biofilm. After incubation for 3 weeks, the samples were treated for 24 hours with saline (control), saturated calcium hydroxide solution (CH), 2% chlorhexidine solution (CHX), and 50 µg/mL HBD3 solution. A commercial biofilm/viability assay kit was used to assess cell viability and analyze the 3-dimensional architecture of biofilms. The percentage of dead cells was determined from the ratio of biovolumes for the red subpopulation and the total biofilm. RESULTS: Three medication groups showed a significant reduction of biovolume within the biofilms compared with the control group (P < .001). The HBD3-treated biofilms had a higher percentage of dead cells than the other medication groups (P < .05). The CH and CHX groups showed higher levels of bactericidal activity than saline (P < .05), and there was no significant difference between the 2 groups (P > .05). CONCLUSIONS: HBD3 peptide exhibited more antibacterial activity against mature multispecies biofilms in vitro than either CH or CHX.

Analysis of six heavy metals in Ortho mineral trioxide aggregate and ProRoot mineral trioxide aggregate by inductively coupled plasma-optical emission spectrometry.

Ortho mineral trioxide aggregate (MTA) is a mineral aggregate newly developed for perforation repair, root end filling and pulp capping. The aim of this study was to investigate the levels of cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn) in Ortho MTA and ProRoot MTA. A total of 0.2 g of each MTA was digested using a mixture of hydrochloric and nitric acids and filtered. Six heavy metals in the resulting filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (n = 5). The results were statistically analyzed using the Mann-Whitney U-test. The concentrations of Cd, Cu, Fe, Mn, Ni and Zn in Ortho MTA were 0.10, 7.73, 49.51, 2.58, 0.82 and 10.09 p.p.m., respectively. The concentrations of Cd, Cu, Fe, Mn, Ni and Zn in ProRoot MTA were 0.16, 9.38, 1438.11, 74.51, 18.98 and 4.05 p.p.m., respectively. In conclusion, Ortho MTA had lower levels of Cd, Cu, Fe, Mn and Ni than ProRoot MTA.

Effect of heat treatment on cyclic fatigue resistance, thermal behavior and microstructures of K3 NiTi rotary instruments.

OBJECTIVE: The aim of this study was to investigate the effect of heat treatment on the cyclic fatigue resistance, thermal behavior and microstructural changes of K3 NiTi rotary instruments. MATERIALS AND METHODS: Twelve control (as-received) and 12 experimental (heat-treated) K3 NiTi rotary instruments were compared in this study. Those experimental K3 instruments were heated in a furnace for 30 min at 450°C and then quenched in water. The cyclic fatigue resistance was measured with a fatigue tester. The thermal characteristic and the microstructures of both instruments were investigated by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM), respectively. RESULTS: There was a significant increase in the cyclic fatigue resistance between the heat-treated instruments and the as-received instruments (T-test, p < 0.05). DSC showed that the as-received and heat-treated samples were different, with an increased Af (austenite-finish temperature) for the latter. TEM analysis revealed that both as-received and heat-treated instruments were composed mainly of an austenite phase. However, the heat-treated samples had an increased appearance of larger grains, twinning martensite, TiO2 surface layer and a Ni-rich inner layer. CONCLUSIONS: Heat treatment increased the cyclic fatigue resistance of NiTi files and changed the thermal behavior of the instruments without marked changes in the constituting phases of NiTi alloy.

Effects of calcium phosphate endodontic sealers on the behavior of human periodontal ligament fibroblasts and MG63 osteoblast-like cells.

In regard to biological properties of endodontic sealers, there are many characteristics that should be considered. The aim of this study was to examine the biological effects of new calcium phosphate-based root canal sealers, CAPSEAL I and CAPSEAL II (CPS), on human periodontal fibroblast cells by examining the expression levels of inflammatory mediators and to compare the effects of CPS on the viability and osteogenic potential of human osteoblast MG63 cells compared to those of other commercially available calcium phosphate sealers [Apatite Root Sealer type I (ARS I) and Apatite Root Sealer III (ARS III); Sankin Kogyo, Tokyo, Japan] and a zinc oxide eugenol-based sealer (Pulp Canal Sealer EWT [PCS EWT]; Kerr, Detroit, MI). The levels of IL-6 in the new CPS group (CAPSEAL I, II) were higher than those in the control and all experimental groups at all time points after 2 h. TGF-ß1 and FGF-1 levels decreased at 72 h compared to the levels in the control, in cells treated with every sealers except ARS I. The new CPS sealers showed low cytotoxicity. Reverse transcription polymerase chain reaction showed that CAPSEAL I, II, and Apatite Root Sealer type III induced expression of early stage markers of differentiation (alkaline phosphatase and osteopontin) at 7 days. Also, new CPS showed higher mineralized nodule formation at 28 days. These results suggest that CAPSEAL I and II facilitate the periapical dentoalveolar and alveolar healing by controlling cellular mediators from PDL cells and osteoblast differentiation of precursor cells.

Effect of laser-activated irrigation of 1320-nanometer Nd:YAG laser on sealer penetration in curved root canals.

INTRODUCTION: The purpose of this study was to investigate the efficacy of laser-activated irrigation (LAI) of 1320-nm neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) laser on sealer penetration into dentinal tubules in the presence of 5.25% sodium hypochlorite (NaOCl) or 17% ethylenediaminetetraacetic acid (EDTA). METHODS: The curved root canals (>20°) from 63 extracted human molars (negative control, n = 3) were prepared to size #30.06 with NaOCl irrigation. Teeth were divided into 4 groups (n = 15) as follows: group N, NaOCl irrigation without LAI; group E, EDTA irrigation without LAI; group NL, LAI with NaOCl; group EL, LAI with EDTA. In all groups, the laser fiber was inserted and withdrawn 4 times for 5 seconds each. Teeth were obturated with gutta-percha and fluorescent-labeled sealer. Transverse sections at 2 and 5 mm from root apex were examined with confocal laser scanning microscopy, and the percentage of sealer penetration into dentinal tubules was measured. RESULTS: Groups E, NL, and EL showed higher percentage of sealer penetration than group N (P < .05). With NaOCl as irrigant, LAI (group NL) resulted in significantly higher amount of sealer penetration than nonactivated group (group N) in both levels (P < .05). However, with EDTA, no significant differences in sealer penetration were observed between the laser-activated group (group EL) and its nonactivated counterpart (group E) in both levels (P > .05). CONCLUSIONS: The 1320-nm Nd:YAG laser activation with either NaOCl or EDTA was much better than NaOCl irrigation alone and as effective as EDTA final flush for sealer penetration into dentinal tubules. Additional use of laser with EDTA did not improve the quality of obturation in the curved canals.

Evaluation of the safety and efficiency of novel metallic ultrasonic scaler tip on titanium surfaces.

AIM: To evaluate the safety and efficiency of novel ultrasonic scaler tips, conventional stainless-steel tips, and plastic tips on titanium surfaces. MATERIAL AND METHODS: Mechanical instrumentation was carried out using conventional ultrasonic scalers (EMS, Nyon, Switzerland) with novel metallic implant tip (BS), a plastic-headed tip (ES), a plastic tip (PS) and a conventional stainless-steel tip (CS) on 10 polished commercially pure titanium disks (Grade II) per group. Arithmetic mean roughness (R(a) ) and maximum height roughness (R(y) ) of titanium samples were measured and dissipated power of the scaler tip in the tip-surface junction was estimated to investigate the scaling efficiency. The instrumented surface morphology of samples was viewed with a scanning electron microscope (SEM) and surface profile of the each sample was investigated using contact mode with a commercial atomic force microscope (AFM). RESULTS: There were no significant differences in surface roughness (R(a) and R(y) ) among BS, ES, and PS group. However, CS group showed significant higher surface roughness (R(a) and R(y) ). The efficiency of CS tip is twice as much higher than that of BS tip, the efficiency of BS tip is 20 times higher than that of PS tip, and the efficiency of BS tip is 90 times higher than that of ES tip. CONCLUSION: Novel metallic copper alloy ultrasonic scaler tips may minimally influence the titanium surface, similar to plastic tip. Therefore, they can be a suitable instrument for implant maintenance therapy.

Chemical interaction of alexidine and sodium hypochlorite.

INTRODUCTION: Recent studies have reported the color change and formation of precipitates containing para-chloroaniline (PCA) after a reaction of sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Alexidine (ALX), a biguanide disinfectant similar to CHX, has greater affinity for bacterial virulence factors than CHX. This study determined by electrospray ionization mass spectrometry (ESI-MS) and scanning electron microscopy (SEM) whether the chemical interaction between ALX and NaOCl results in PCA or precipitates. METHODS: ESI-MS was performed on 4 different concentrations of ALX (1%, 0.5%, 0.25%, and 0.125%) with 4% NaOCl to detect the presence of PCA. As control groups, 1% ALX, 0.5% PCA, and a mixture of 2% CHX and 4% NaOCl were analyzed. The formation of precipitates on the dentinal surfaces of premolar root canals treated with the solutions of ALX and NaOCl (AN) or CHX and NaOCl (CN) was observed by SEM and the color change in the reaction solutions was also analyzed. RESULTS: ESI-MS showed that the peak (mass/charge ratio = 128.026) in the PCA spectrum was not detected in any of the 4 AN solutions, whereas the peak was found in the CN solution. SEM revealed precipitates covering dentinal surfaces in the CN solution. The AN solutions produced no precipitate. The AN solutions changed in color from light yellow to transparent with decreasing ALX concentration, whereas peach-brown discoloration was observed in the CN solution. CONCLUSIONS: The interaction of ALX and NaOCl did not produce PCA or precipitates, and the color of the reacted solution changed transparent with decreasing ALX concentration.

Heavy metal analysis of ortho MTA and ProRoot MTA.

INTRODUCTION: Recently, several kinds of mineral trioxide aggregate (MTA)-based products have been introduced in endodontics. Ortho MTA (BioMTA, Seoul, Republic of Korea) is one of those products, which was developed for retrograde filling, perforation repair, orthograde root canal obturation, and direct pulp capping. The inclusion of heavy metals in MTA-based materials is of concern because they come into direct contact with hard and soft tissues. The aim of this study was to investigate and compare the levels of arsenic (As), chromium (Cr), hexavalent chromium (Cr(6+)), and lead (Pb) in Ortho MTA and ProRoot MTA. METHODS: One gram of each MTA was digested using a mixture of hydrochloric and nitric acids and filtered. The As, Cr, and Pb in the resulting filtrates were analyzed by inductively coupled plasma-optical emission spectrometry. The level of Cr(6+) was measured by the methods suggested in the Korean Standard L 5221. The results were statistically analyzed using the Mann-Whitney U test. RESULTS: The concentration of As in ProRoot MTA was 1.16 ppm, but As was not detected in Ortho MTA. Cr(6+) and Pb were not detected in either MTA. Ortho MTA contained significantly less Cr than ProRoot MTA (P < .05). CONCLUSIONS: Ortho MTA and ProRoot MTA meet the ISO specification 9917-1 regarding the safety limits of As and Pb and are safe biomaterials when the purity of As, Cr(6+), and Pb is considered.

Matrix metalloproteinase-8 and substance P levels in gingival crevicular fluid during endodontic treatment of painful, nonvital teeth.

OBJECTIVE: The aim of this study was to investigate levels of matrix metalloproteinase-8 (MMP-8) and substance P (SP) in gingival crevicular fluid (GCF) during root canal treatment (RCT) of nonvital teeth. STUDY DESIGN: Patients scheduled for nonsurgical RCT were prospectively selected; all patients provided informed consent. GCF samples were collected from teeth scheduled for RCT and their contralateral teeth across 3 different time periods. MMP-8 and SP levels were measured using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using a mixed model analysis and the Pearson correlation analysis. RESULTS: Patients' subjective pain levels were significantly related to both MMP-8 and SP levels. MMP-8 and SP levels in GCF were decreased during RCT, and they showed a positive correlation with each other (P < .05). CONCLUSIONS: This study demonstrated that periradicular inflammation of endodontic origin can elevate SP and MMP-8 levels in GCF.

Shaping ability of reciprocating motion in curved root canals: a comparative study with micro-computed tomography.

INTRODUCTION: Recently, root canal shaping with reciprocating motion has been postulated to reduce the possibility of unexpected file fractures. However, there has been little information on the shaping capability of this reciprocating motion preparation technique. Therefore, the purpose of this study was to evaluate the shaping ability of reciprocating motion when compared with continuous rotation motion in curved root canals. METHODS: The mesiobuccal and distobuccal canals of 20 extracted maxillary molars with curvatures of 20-45 degrees were instrumented with a series of ProTaper rotary files. The canals in the continuous rotation motion (CM) group (n = 20) were prepared by using continuous rotation with pecking motion, whereas the canals in the reciprocating motion (RM) group (n = 20) were prepared with reciprocating motion (clockwise 140 degrees and counterclockwise 45 degrees). Basic geometric parameters such as curvature, root canal volume, surface area, and structure model index (SMI) before and after canal shaping were evaluated by using micro-computed tomography. The degrees and directions of transportation were also measured, and statistical analysis was carried out with one-way analysis of variance and Tukey post hoc tests. RESULTS: There were no significant differences between the 2 groups in canal curvature, volume, surface area, and SMI categories measured before preparation (P > .05). Changes in curvature, root canal volume, surface area, and SMI were not affected by the instrumentation technique used (P > .05). There were no significant differences in the degrees and directions of transportation between CM and RM groups (P > .05). CONCLUSIONS: The application of reciprocating motion during instrumentation did not result in increased apical transportation when compared with continuous rotation motion, even in the apical part of curved canals. Reciprocating motion might be an attractive alternative method to prevent procedural errors during root canal shaping.

Evaluation of pH and calcium ion release in capseal I and II and in two other root canal sealers.

OBJECTIVE: The aim of this study was to compare the pHs and calcium ion releases of newly developed, calcium phosphate-based root canal sealers (Capseal I and II) with those of Sealapex (SA) and Sankin Apatite Root Sealer III (SARS III). STUDY DESIGN: Each material (n = 10) was mixed, inserted into polyvinyl chloride (PVC) tubes, and immersed in a vial containing deionized water. The control group consisted of empty PVC tubes (n = 10). The pHs and calcium ion releases were measured by pH meter and ICP-AES (inductively coupled plasma atomic emission spectrometer) at 24 hours and 96 hours, and at 7, 15, and 28 days. The results were analyzed with the Kruskal-Wallis test. RESULTS: Capseal I and II produced pHs and calcium ion releases higher than or equal to those of SA and SARS III (P < .05). CONCLUSIONS: Capseal I and II resulted in higher alkalinity and higher calcium ion releases than SA and SARS III.

Mesiobuccal root canal anatomy of Korean maxillary first and second molars by cone-beam computed tomography.

OBJECTIVE: The aim of this study was to investigate the types of canal configurations and the incidence of a second mesiobuccal (MB2) canal in Korean maxillary molar mesiobuccal (MB) roots by analyzing cone-beam computed tomographic (CBCT) images. STUDY DESIGN: Three-dimensional CBCT images of 458 maxillary first molars and 467 second molars from 276 Korean patients were analyzed to determine the incidence of an MB2 canal, the types of canal configurations, and the correlations between the incidence of an MB2 canal and age, gender, and tooth position. RESULTS: The incidence of 2-canaled MB roots was 71.8% in first molars and 42.2% in second molars, with the most common configurations being Weine types III and II. The frequency of an MB2 canal decreased with age in both molars (P < .05). CONCLUSIONS: Types III and II canal configurations were the most prevalent in the 2-canaled MB roots of Korean maxillary molars.

Lifespan of one nickel-titanium rotary file with reciprocating motion in curved root canals.

INTRODUCTION: The purpose of this study was to examine the lifespan of one nickel-titanium (NiTi) rotary file when used in reciprocating motion and to compare the time required for its preparation of a curved root canal using both reciprocating and continuous motion. METHODS: One hundred twenty curved canals from 60 extracted maxillary and mandibular molars were selected for measuring the mean number of uses. Each canal was prepared with reciprocating motion until the ProTaper F2 single file (Dentsply Maillefer, Ballaigues, Switzerland) reached the working length. One file was used until it was fractured. Another 60 canals were divided into two groups. 30 canals in the continuous rotation motion (CM) group were prepared using continuous rotation following the sequence of ProTaper files, whereas the canals in the reciprocating motion (RM) group (n = 30) were prepared with reciprocating motion with the sole use of the ProTaper F2. The total root canal preparation time was measured until the F2 file finally reached the working length in both groups. RESULTS: A total of 11 files were used in the preparation of 120 curved root canals. The average lifespan of one F2 file was 10.60 ± 4.35 canals with the longest lifespan of 21 canals. The total time for canal preparation was 46.42 ± 18.12 seconds and 21.15 ± 6.70 seconds in the CM and RM groups, respectively. There was a statistically significant difference between the groups (p < 0.01). CONCLUSION: Within the limitation of this study, one F2 file can be safely used to the working length of curved canals at least six times under reciprocating motion. Reciprocating preparation with only one F2 file was much faster than root canal instrumentation with continuous rotation.

Effects of root canal irrigants on the push-out strength and hydration behavior of accelerated mineral trioxide aggregate in its early setting phase.

INTRODUCTION: The purpose of this study was to evaluate the effects of endodontic irrigants on the push-out strength and hydration behavior of accelerated mineral trioxide aggregate (MTA) in its early setting phase. METHODS: In an in vitro perforation model, MTA with or without 10% CaCl(2) was condensed and allowed to initial set for 10 minutes. The samples were divided into four groups (n = 10) to be immersed into either 3.5% sodium hypochlorite (NaOCl) or 2% chlorhexidine gluconate (CHX) for 30 minutes and then allowed to set for 48 hours. In the control group, a wet cotton pellet was placed over MTA. The maximum force applied to the set MTA mixture before dislodgement was recorded. Irrigant-treated surfaces were examined using a scanning electron microscope (SEM). Chemical elements of these surfaces were also analyzed by energy dispersive x-ray spectroscope (EDS). RESULTS: The push-out strength of group A1 (NaOCl-treated accelerated MTA) was the highest of all groups. When compared with nonaccelerated MTA, CaCl(2)-accelerated MTA showed significantly higher push-out strength (p < 0.05). NaOCl-treated groups showed significantly higher push-out strength than CHX-treated groups (p < 0.05). Scanning electron microscopic examination and EDS analysis showed that the formation of calcium hydroxide crystals on accelerated MTA exposed to NaOCl was increased compared with those of the control group. CONCLUSION: These findings imply that the use of accelerated MTA under the NaOCl irrigation was effective in perforation repair without altering its hydration behavior even in the early setting phase.

Gene expression profiling concerning mineralization in human dental pulp cells treated with mineral trioxide aggregate.

INTRODUCTION: This study investigated changes in gene expressions related to mineralization when mineral trioxide aggregate (MTA) is applied in vitro to human dental pulp cells (HDPCs). METHODS: MTA in a Teflon tube (diameter 10 mm, height 2 mm) was applied to HDPCs. Empty tube-applied HDPCs were used as negative control. Total RNA was extracted at 6, 24, and 72 hours after MTA application for microarray analysis. The results were confirmed selectively by performing reverse transcriptase-polymerase chain reaction for genes that showed changes of more than 2-fold or less than half. RESULTS: Of the 24,546 genes, 109 genes were up-regulated more than 2-fold (eg, THBS1, VCAN, BHLHB2, FN1, COL10A1, TUFT1, and HMOX1), and 69 genes were down-regulated below 50% (eg, DCN, SOCS2, and IL8). CONCLUSIONS: These results suggest that rather than being a bio-inert material, MTA affects pulp cells in various ways. MTA appears to affect mineralization and induces slight inflammation and protective role against slight inflammation.

Human periodontal ligament cell response to a newly developed calcium phosphate-based root canal sealer.

OBJECTIVES: The aim of this study was to investigate the cellular effects of newly developed calcium phosphate-based sealers (CAPSEAL I and II) using cultured human periodontal ligament cells (HPDLCs) compared with epoxy resin sealer (AH26; Dentsply, DeTrey, Konstanz, Germany), zinc oxide eugenol [ZOE] sealer (extended working time [EWT]; Kerr Corporation, Orange, CA), and CPC sealer (Sankin apatite sealer; Sankin-kogyo, Tokyo, Japan). METHODS: Cell viability by -(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide assay, cell attachment by scanning electron microscopy, osteoblastic differentiation and inflammatory mediators by reverse-transcriptase polymerase chain reaction, Western blotting, and alizarin red staining were evaluated. RESULTS: The cytotoxicities of CAPSEAL I and II were less than those of AH 26 and EWT after 1 and 14 days. Cells on CAPSEAL I and II were spread better as compared with those on other sealers. Mineralization after 14 days and the expression of osteoblastic differentiation markers such as alkaline phosphate and osteonectin messenger RNA increased in CAPSEAL I- and II-exposed HPDLCs after 1 and 3 days, whereas the production of inflammatory mediators, including cyclooxygenase-2, inducible nitric oxide synthetase, and reactive oxygen species (ROS), were lower than in other sealers. CONCLUSIONS: These results suggest that both CAPSEAL I and II show less cytotoxicity and inflammatory mediators compared with other sealers and have the potential to promote bone regeneration as root canal sealers.