Postendodontic Pain after Pulpotomy or Root Canal Treatment in Mature Teeth with Carious Pulp Exposure: A Multicenter Randomized Controlled Trial.

This equivalence, randomized, clinical trial aimed to compare the postoperative pain of root canal therapy (RCT) with pulpotomy with mineral trioxide aggregate (PMTA) or calcium-enriched mixture (PCEM) in permanent mature teeth. In seven academic centers, 550 cariously exposed pulps were included and randomly allocated into PMTA (n = 188), PCEM (n = 194), or RCT (n = 168) arms. Preoperative "Pain Intensity" (PI) on Numerical Rating Scale and postoperative PIs until day 7 were recorded. Patients' demographic and pre-/intra-/postoperative factors/conditions were recorded/analysed. The arms were homogeneous in terms of demographics. The mean preoperative PIs were similar (P=0.998), the mean sum PIs recorded during 10 postoperative intervals were comparable (P=0.939), and the trend/changes in pain relief were parallel (P=0.821) in all study arms. The incidences of preoperative moderate-severe pain in RCT, PMTA, and PCEM arms were 56.5%, 55.7%, and 56.7%, which after 24 hours considerably decreased to 13.1%, 10.6%, and 12.9%, respectively (P=0.578). The time span of endodontic procedures was statistically different; RCT = 69.73, PMTA = 35.37, and PCEM = 33.62 minutes (P < 0.001). Patients with greater preoperative pain, symptomatic apical periodontitis, or presence of PDL widening suffered more pain (P=0.002, 0.035, and 0.023, resp.); however, other pre-/intra-/postoperative factors/conditions were comparable. Pulpotomy with MTA/CEM and RCT demonstrate comparable and effective postoperative pain relief.

Comparing the Efficacy of Toluidine Blue, Methylene Blue and Curcumin in Photodynamic Therapy Against Enterococcus faecalis.

Introduction: Antimicrobial photodynamic therapy (aPDT) as a supplement to the conventional root canal preparation has shown promising results. Previous studies have adopted various combinations of light sources and photosensitizers, which makes it difficult to compare the disinfection efficacy of different PDT protocols. The aim of the present study was to compare the efficacy of three photosensitizers (toluidine blue, methylene blue, and curcumin) in PDT using LED against Enterococcus faecalis in root canal disinfection. Methods: Root canals of 54 single-rooted extracted teeth were prepared using the ProTaper Gold rotary system and were incubated with E. faecalis for three weeks. They were then randomly divided into five experimental groups and a control group: (1) Irrigation with 2.5% NaOCl for 30 seconds, (2) NaOCl irrigation followed by TB-PDT, (3) NaOCl irrigation followed by MB-PDT, (4) NaOCL irrigation followed by curcumin-PDT, (5) Curcumin solvent (1% ethanol+1% BSA), (6) Control (irrigation with normal saline). Sampling was done by collecting dentin shavings from the root canals, and colony-forming units were determined for each treatment group. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. The significance level was set at P<0.05. Results: In all treatment groups, the mean values of colony forming unit (CFU) decreased by 99% compared to the control group. The lowest mean values of CFU were observed in groups 2 and 4, followed groups 3, 1, and 5 respectively. The mean CFU count in group 2 was significantly lower than that of group 1 (P value=0.011), while there were no significant differences among groups 1, 3, and 4 (P value >0.05). Conclusion: The adjunction of toluidine blue-mediated PDT by means of a light-emitting diode to NaOCl irrigation increased its antibacterial efficacy against E. faecalis and could be an effective complementary method in root canal disinfection.

Setting Time and Surface Microhardness of Mineral Trioxide Aggregate and 1% and 5% Fluoride-Doped Mineral Trioxide Aggregate Mixed with Water and Gel-like Polymer.

Introduction: Mineral trioxide aggregate (MTA) is extensively used in endodontics. However, it has limitations such as long setting time, low compressive strength and poor handling properties. Our study aimed to compare the setting time and surface microhardness of MTA and fluoride-doped MTA (FMTA) using gel-like polymer (GLP) or distilled water (DW) as liquid. Methods and Materials: An MTA-like cement was prepared by mixing Portland cement, bismuth oxide and gypsum (75%, 20% and 5%, respectively). FMTA (1% and 5%) was made by substituting 1% and 5% of MTA powder with fluoride. GLP, composed of methyl cellulose (MC) and propylene glycol (PG), was used as the hydrating liquid and compared with distilled water. Six experimental groups (n=10) were examined for each test. The samples were subjected to Vickers surface microhardness test after 4 and 28 days. Setting time was measured using ANSI/ADA standards. Data was analyzed using two-way and repeated measured ANOVA and the Tukey HSD tests. Results: The MTA-like cement hydrated with GLP showed a significantly reduced setting time (P<0.05); 1% FMTA, mixed with GLP, had the shortest initial and final setting times. The microhardness values of all samples increased at different rates during 28 days (P<0.00001). The microhardness significantly decreased by addition of fluoride to MTA (P<0.001). Conclusions: The results of the present in vitro study suggested that using GLP as the hydrating liquid enhances the setting time with no adverse effect on the surface microhardness. However, adding fluoride can negatively affect the microhardness of MTA.

Subcutaneous Reaction of Rat Tissues to Nanosilver Coated Gutta-Percha.

INTRODUCTION: Gutta-percha (GP), is a neutral and non-toxic material. The aim of this animal study was to compare the biocompatibility of nanosilver coated GP (NS-GP) with conventional GP in subcutaneous tissues in a rat model. METHODS AND MATERIALS: Conventional GP and NS-GP were subcutaneously implanted in the backs of 20 male Wistar rats (n=10). A control animal was assigned for each trial period. Ten animals were sacrificed after 7 and 30 days and light microscopic evaluation of tissue reaction to NS-GP (n=20) and conventional GP (n=20) was accomplished. The Mann-Whitney U, Wilcoxon Signed Ranks, Fisher Exact, and McNemar tests were used for statistical analysis of the data. RESULTS: After 7 days, inflammation was moderate and mild for NS-GP and conventional GP, respectively (P<0.001). After 30 days, no inflammation was discernible in conventional GP. However, mild inflammation was reported for NS-GP (P<0.001). Regarding inflammatory cell type, there was a significant difference between two experimental groups at both times (P<0.001). CONCLUSION: Inflammation decreased over time in both groups. Fibrous connective tissue, a representative of healing and control of inflammatory process, surrounded both test materials. NS-GP was biocompatible and might be a reasonable endodontic obturation material.

Comparison of Antifungal Activity of 2% Chlorhexidine, Calcium Hydroxide, and Nanosilver gels against Candida Albicans.

OBJECTIVES: Residual microorganisms in the root canal system (RCS) after endodontic therapy such as Candida albicans are a major cause of endodontic failure. Calcium hydroxide (CH) and chlorhexidine (CHX) have suitable antimicrobial activity against bacteria and can be used as intracanal medicaments. Nanosilver has also shown antimicrobial activity against microorganisms. This study aimed to compare the antifungal effect of calcium hydroxide, 2% chlorhexidine and nanosilver gels on Candida albicans. MATERIALS AND METHODS: Eighty-one single-rooted teeth were selected. After root canal preparation, the teeth were contaminated. After culture, the teeth were randomly divided into 4 groups. In experimental groups, 24 teeth were selected and completely filled with CH, 2% CHX and nanosilver gels in each group. Nine teeth were selected in the control group and filled with saline solution. After 1, 3, and 7 days, samples were obtained by #30 sterile paper points, and #2 and #4 Gates Glidden drills and cultured on solid Sabouraud agar. RESULTS: The results demonstrated that CH and 2% CHX had equal antifungal effects on samples taken by paper point and #2 Gates Glidden drill at all time points. Both CH and 2% CHX were more effective than nanosilver at all time periods. There was no statistically significant difference between medicaments in samples taken by #4 Gates Glidden drill. CONCLUSION: CH and 2% CHX gels have significantly higher antifungal activity than nanosilver gel. Also, CH and 2% CHX gels are equally effective against Candida albicans.

Toxicity of calcium hydroxide nanoparticles on murine fibroblast cell line.

INTRODUCTION: One of the major contributing factors, which may cause failure of endodontic treatment, is the presence of residual microorganisms in the root canal system. For years, most dentists have been using calcium hydroxide (CH) as the intracanal medicament between treatment sessions to eliminate remnant microorganisms. Reducing the size of CH particles into nanoparticles enhances the penetration of this medicament into dentinal tubules and increases their antimicrobial efficacy. This in vitro study aimed to compare the cytotoxicity of CH nanoparticles and conventional CH on fibroblast cell line using the Mosmann's Tetrazolium Toxicity (MTT) assay. METHODS AND MATERIALS: This study was conducted on L929 murine fibroblast cell line by cell culture and evaluation of the direct effect of materials on the cultured cells. Materials were evaluated in two groups of 10 samples each at 24, 48 and 72 h. At each time point, 10 samples along with 5 positive and 5 negative controls were evaluated. The samples were transferred into tubes and exposed to fibroblast cells. The viability of cells was then evaluated. The Two-way ANOVA was used for statistical analysis and the level of significance was set at 0.05. RESULTS: Cytotoxicity of both materials decreased over time and for conventional CH was lower than that of nanoparticles. However, this difference was not statistically significant (P>0.05). CONCLUSION: The cytotoxicity of CH nanoparticles was similar to that of conventional CH.

Antimicrobial effects of four intracanal medicaments on enterococcus faecalis: an in vitro study.

INTRODUCTION: The aim of this in vitro study was to evaluate the antimicrobial activity of four intracanal medicaments on Enterococcus Faecalis (E. Faecalis). METHODS AND MATERIALS: Fifty extracted single-rooted human teeth were prepared with standard method. After contaminating the canals with E. Faecalis, the samples were divided into one control and four experimental groups (n=10). The teeth in each group were treated with one of the experimental medicaments, including calcium hydroxide (CH), 2% chlorhexidine gel (CHX), triple antibiotic paste (TAP) and nanosilver (NS). In control group, canals were filled with a neutral gel. Microbial samples were obtained from the roots after 7 days and optical density of the cultures was determined after 24 h of incubation. Optical density values were analyzed with one-way analysis of variance and Tukey's post hoc tests. RESULTS: CHX gel and TAP were significantly more effective against E. Faecalis than CH, which was also significantly more efficient than NS and normal saline. In the paper cone samples, CHX gel was more effective than TAP; however, samples obtained with sizes 2 and 4 Gate Glidden drills, indicated that TAP was much more efficient than CHX. Normal saline and NS had similar effects on E. Faecalis. CONCLUSION: NS gel was not efficient enough against E. Faecalis; however, TAP and CHX gel showed better antibacterial efficacy than CH and can be used as an alternative intracanal medicaments in root canal therapies.

Evaluation of push-out bond strength of AH26 sealer using MTAD and combination of NaOCl and EDTA as final irrigation.

BACKGROUND: During endodontic procedures, the smear layer is formed as a result of mechanical instrumentation of the canal. Combination of ethylenediamine tetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) is widely used for removal of the smear layer. Application of Mixture of tetracycline, acid, and detergent (MTAD) as final irrigant subsequent to initial irrigation of 1.35% NaOCl has been proposed to increase clinical efficiency, biocompatibility and prolonged intra-canal antibacterial activity. Considering the importance of adhesion of endodontic sealers to the dentin walls of a prepared root canal, the present study evaluated push-out bond strength of AH26 sealer using final irrigation of MTAD and EDTA + NaOCl. MATERIALS AND METHODS: Sixty five single-rooted teeth were prepared endodontically with the same chemomechanical technique and were randomly divided into three groups based on their final irrigation regimen: 17% EDTA + 5.25% NaOCl group (n =30), MTAD group (n =30) and control group (n =5). Obturation of the canals was performed with gutta-percha and AH26 sealer. All teeth were sectioned in order that two specimens of 1 mm thickness were obtained from the coronal and the middle one third of each root resulting in 60 specimens for each experimental group and 10 specimens for control group. For push-out test, universal-testing machine was used to exert a constant compressive apico-coronal load at a speed of 0.5 mm/min. Minimum amount of compressive load caused dislodgement was measured and converted into megapascal (MPa) scale. One-way analysis of variance and the post hoc Tukey test were used for statistical analysis of the data (α = 0.05). RESULTS: In MTAD group, mean micro-push-out bond strength of AH26 sealer to dentin walls was obtained 2.23 MPa compared to 2.0 MPa for EDTA + NaOCl group. The mean bond strength of AH26 sealer to dentin walls was significantly greater using MTAD compared with combination of EDTA and NaOCl or saline. CONCLUSION: MTAD final rinse significantly increased micro-push-out bond strength of AH26 sealer to canal dentin walls compared with EDTA + NaOCl.

Cytotoxicity evaluation of three resin-based sealers on an L929 cell line.

BACKGROUND: Endodontic sealers usually come in contact with adjacent tissues and their biocompatibility is key in a successful treatment. The purpose of this study was to assess the cytotoxicity of three resin-based sealers, namely AH Plus, EndoREZ, and Epiphany in set and fresh states on an L929 cell line. MATERIALS AND METHODS: In this in vitro experimental study, the materials were mixed according to the manufacturers' instructions, and were divided into two groups, fresh and set. The elutes of materials were prepared separately and were incubated with L929 fibroblasts for 1 hour, 24 hours, and 72 hours. Pulp Canal Sealer and Dulbecco's Modified Eagle Medium (DMEM) served as positive and negative controls respectively. Cell viability was evaluated by MTT assay ([3-4,5-dimethyl thiazol-2-yl]-2,5-diphenyltetrazolium bromide succinate), after 1 hour, 24 hours, and 72 hours. The data were analyzed by analysis of variance (ANOVA), and Tukey multiple comparison test. RESULTS: After 1 hour, fresh Epiphany and fresh AH Plus were significantly more cytotoxic than their set samples. No significant difference was perceived between cytotoxicity of fresh state of sealers and positive control, or between set state and negative control. After 24 hours, both fresh and set samples of all materials were significantly more cytotoxic than the negative control group, and were less cytotoxic than the positive control group. After 72 hours, the fresh and set samples of all materials were as cytotoxic as the positive control group. At each time point, no significant difference was perceived among different materials in terms of cell viability. CONCLUSION: The observed differences among the cytotoxicity of AH Plus, EndoREZ, and Epiphany did not reach a significant level at comparable time points after exposure.

A Survey on NiTi Rotary Instruments Usage by Endodontists and General Dentist in Tehran.

INTRODUCTION: The aim of this study was to assess the extent of adoption, application and the associated issues with the nickel-titanium (NiTi) rotary instruments and techniques amongst endodontists and general dentists in Tehran. MATERIALS AND METHODS: A total of 33 questions classified in six categories of demographics, frequency rate of NiTi rotary instrumentation and information. The sample size comprised of 100 endodontists and 100 general dental practitioners in Tehran. RESULTS: The overall response rate was 73.5%. NiTi rotary instruments were used by 98.4% and 50.6% of endodontists and general dentists, respectively. The main mentioned reason for not using rotary NiTi instruments was "lack of education". Among all procedural faults with NiTi, the most prevalent was "intra-canal file fracture" (88.5%) followed by "apical transportation" (71.2%) and "ledging" (68.3%). The main factors associated with the first procedural accident were "over-use" and "excessive pressure". CONCLUSION: Dentists need more training and more comprehensive education regarding NiTi rotary instruments and techniques.

Substance P and CGRP expression in dental pulps with irreversible pulpitis.

The purpose of this study was to compare substance P (SP) and calcitonin gene-related peptide (CGRP) expression in pulp tissue with clinically diagnosed symptomatic and asymptomatic irreversible pulpitis. Healthy pulps acted as controls. Five normal pulps and 40 with irreversible pulpitis (20 symptomatic and 20 asymptomatic) were obtained from 45 different patients. SP and CGRP expression was determined by competition binding assays using enzyme immunoassay. anova and Mann-Whitney tests were used to ascertain if there were statistically significant differences between the groups. The results showed that neuropeptides were found in all pulp samples. The highest and the lowest expressions for SP and CGRP were found in symptomatic irreversible pulpitis and healthy pulps groups, respectively. The differences between healthy pulps and the groups of pulps having irreversible pulpitis were significant (P < 0.001). Although Mann-Whitney's post-hoc tests showed statistically significant differences in CGRP expression between two pulpitis groups (P < 0.05), differences in SP expression between symptomatic and asymptomatic irreversible pulpitis groups were not significant. This study demonstrated that the expression of CGRP and SP is significantly higher in pulps with irreversible pulpitis compared with healthy pulps.

Effect of 17% EDTA and MTAD on intracanal smear layer removal: a scanning electron microscopic study.

The purpose of this study was to determine the effectiveness of MTAD as the final irrigant to remove the smear layer, compared with that of 17% EDTA, both following root canal irrigation with 5.25% sodium hypochlorite (NaOCl). Fifty-five extracted maxillary and mandibular single-rooted human teeth were prepared by a crown-down technique using rotary 0.04 and 0.06 taper nickel-titanium files. 5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions as final rinse: 5.25% sodium hypochlorite, 17% EDTA or MTAD. The presence or absence of smear layer in the coronal, middle and apical portion of each canal was examined with a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 17% EDTA was used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals.

Cytotoxicity of Cold Ceramic Compared with MTA and IRM.

INTRODUCTION: Biocompatibility is a desirable feature for root-end filling materials. In this study we aimed to compare a new material called cold ceramic (CC) with intermediate restorative material (IRM) and mineral trioxide aggregate (MTA) using Methyl-tetrazolium bromide (MTT) assay. MATERIALS AND METHODS: The materials were tested in fresh and set states: (n=108). The cytotoxicity was compared using L929 fibroblasts as an indicator; tested materials were eluted with culture medium according to ISO: 109935 standard. Distilled water and culture medium served as positive and negative controls, respectively (n=36). The results were evaluated at 1, 24 hours and 7 days. Data were statistically analyzed by one-way ANOVA for each time interval and material status and t-tests. RESULTS: The cytotoxicity of the tested materials were statistically different at the various time intervals (P<0.001). IRM was the most cytotoxic root-end filling material (P<0.001), MTA demonstrated the least cytotoxicity followed by CC. CONCLUSION: Despite displaying the greatest cytotoxicity, IRM is approved by the American Food and Drug Administration (FDA). Cold ceramic had significantly lower cytotoxicity compared to IRM, in all but one subgroup. Further investigations are required to assess the clinical applicability of this novel material.

The efficacy comparison of ibuprofen, acetaminophen-codeine, and placebo premedication therapy on the depth of anesthesia during treatment of inflamed teeth.

The purpose of this study was to elucidate whether premedication therapy with acetaminophen-codeine or ibuprofen is able to increase the depth of anesthesia in inflamed teeth. Sixty patients with the diagnosis of irreversible pulpitis in 1 mandibular tooth requiring root canal therapy (RCT) were selected. Two other teeth in the same quadrant were selected as controls. An electric pulp tester (EPT) was used to evaluate pulp sensitivity at the baseline and after drug administration and anesthesia injection. The subjects were divided into 3 groups randomly, and in each group 1 of the 3 drugs including acetaminophen-codeine, ibuprofen, and placebo were administered 1 hour before anesthesia delivery. After 1 hour, anesthesia was injected and after a waiting period, the EPT measurement was recorded. The reversed EPT scale was used to evaluate the depth of anesthesia achieved during RCT. Data were analyzed to statistically compare the results before and after intervention in cases and controls of each group and among different groups. Significanly lower tooth sensitivity levels (TSLs) were observed after intervention in acetaminophen-codeine and ibuprofen groups, which was more significant in the ibuprofen group. The comparison of inflamed teeth TSLs in the acetaminophen-codeine group and the placebo group after anesthesia and drug administration showed significant differences (P = .001). This comparison between ibuprofen and placebo groups also showed significant differences (P approximately 0). Also, significantly lower TSL of inflamed teeth was observed in the ibuprofen group in comparison with the acetaminophen-codeine group (P = .002). This study reflected preoperative administration of ibuprofen, if not contraindicated, as a drug of choice 1 hour before local anesthesia injection as an effective method for achieving a deep anesthesia during RCT of teeth with irreversible pulpitis.

Clinical and Radiographic Evaluation of Procedural Accidents and Errors during Root Canal Therapy.

INTRODUCTION: Root canal therapy (RCT)_like other dental practices_ can be accompanied with some accidents or unpredictable conditions that are called "procedural accidents". Having the knowledge about these accidents and their etiology is essential to have RCT completion and to prevent the repeat of these accidents. This study was designed to evaluate accidents occurring during RCT in patients referred to endodontic department of Shaheed Beheshti dental school during 2002. MATERIALS AND METHODS: This study was conducted via descriptive method. Data were collected from observation, clinical examination and oral radiographs, and were recorded in questionnaires, 150 cases from the patients referred to endodontic department were selected randomly and different observed RCT errors were analyzed by SPSS software. The Chi-square and Fisher exact tests were used for analysis. RESULTS: The study showed that 101 patients (67.3%) had one type of RCT errors, and remaining (32.7%) were error free. From the errors studied the most prevalent were "void" which was observed in 41 patients (27.3%), and "ledge" in 39 patients (26%) respectively. The prevalence of other accidents were underfilling in 35 patients (23.3%), poor shaping in 30 patients (20%), overfilling in 23 patients (15.3%), transportation in 13 patients (8.7%), zipping in 3 patients (2%), gouging in 1 patients (0.7%), and strip perforation in 1 patients (0.7%), while no case of broken instruments, vertical fracture, furcation and cervical perforation was observed. CONCLUSION: The most prevalent errors were found in instrumentation and obturation steps, therefore more care and attention must be paid to instructor observation and the education of these stages.