Systematic Review

Effect of Corticosteroids on Pain Relief Following Root Canal Treatment: A Systematic Review

Foad Iranmanesh, Masoud Parirokh, Ali Akbar Haghdoost, Paul V. Abbott

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 123-130

Introduction: Post-operative pain and flare-up may occur in up to 58% of patients following root canal treatment. The aim was to conduct a systematic review and a possible meta-analysis to determine the effect of glucocorticosteroid (GCS) on pain following root canal treatment. Methods and Materials: Scopus, MEDLINE and CENTRAL databases were searched up to 30th January 2017 with broad key words. In addition, the reference lists in eligible papers and text books were hand-searched. Assessment of the eligibility of papers and data extraction were performed by two independent reviewers. Results: Of 9891 articles, 18 were recruited as eligible papers. Most of these papers showed pain reducing effect of GCS on post-endodontic pain. Because of wide heterogeneity among the recruited papers, it was not possible to perform meta-analysis. Conclusion: Based on the results of this systematic review, there is a vast heterogeneity amongst articles regarding the use of GCS and their effect on post-operative pain after endodontic treatment. Further investigations with similar methods and materials are needed before meta-analysis on the effect of GCS on post-operative pain following root canal treatment can be performed

Keywords: Corticosteroid; Endodontics; Flare-Up; Meta-Analysis; Post-Operative Pain; Systematic Review


Review Article

Root Canal Irrigants and Dentin Bonding: An Update

Zahed Mohammadi, Shapour Yaripour, Sousan Shalavi, Flavio Palazzi, Saeed Asgary

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 131-136

The purpose of the review was to assess the effect of root canal irrigants on dentin bonding. A PubMed-based search was conducted on the articles published from 1980 to 2016. A brief overview and reviewing the effect on dentin bonding of common root canal irrigation solutions such as sodium hypochlorite (NaOCl), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA), mixture of a tetracycline, acid and a detergent (MTAD) and ozone was conducted. Findings showed that, depending on the type of dentin bonding, using NaOCl may decrease, increase or not affect the bond strength. In addition, due to its broad-spectrum matrix metalloproteinase-inhibitoryeffect, CHX as well as MTAD can significantly improve the resin-dentin bondstability. However, the effect of ozone therapy on bond strength was controversial.

Keywords: Bond Strength; Chlorhexidine; EDTA; MTAD; Ozone; Sodium Hypochlorite

Original Article

Cytotoxicity of Selected Nanoparticles on Human Dental Pulp Stem Cells

Kasra Tabari, Sepanta Hosseinpour, Peter Parashos, Parisa Kardouni Khozestani, Hossein Mohammad Rahimi

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 137-142

Introduction: Nanoparticles are being increasingly applied in dentistry due to their antimicrobial and mechanical properties. This in vitro study aimed to assess and compare the cytotoxicity of four metal oxide nanoparticles (TiO2, SiO2, ZnO, and Al2O3) on human dental pulp stem cells. Methods and Materials: Four suspension with different concentrations (25, 50, 75, 100 µg/mL) of each nanoparticle were prepared and placed into cavities of three 96-well plates (containing 1×104 cells per well that were seeded 24 earlier). All specimens were incubated in a humidified incubator with 5% CO2 at 37°C. Mosmann’s Tetrazolium Toxicity (MTT) assay was used to determine in vitro cytotoxicity of test materials on pulpal stem cells. Cell viability was determined at 24, 48, and 72 h after exposure. Data comparisons were performed using a general linear model for repeated measures and Tukey's post hoc test. The level of significance was set at 0.05. Results: The tested nanoparticles showed variable levels of cytotoxicity and were dose and time dependant. The minimum cell viability was observed in ZnO followed by TiO2, SiO2 and Al2O3. Conclusion: The results demonstrated that cell viability and morphological modifications occurred at the concentration range of 25 to 100 µg/mL and in all nanoparticles. The higher concentration and longer duration of exposure increased cellular death. Our results highlight the need for a more discrete use of nanoparticles for biomedical applications.

Keywords: Cytotoxicity; Dental Pulp Stem Cells; Metal Oxide Nanoparticle 

Root and Canal Morphology of Mandibular Molars in a Selected Iranian Population Using Cone-Beam Computed Tomography

Zahra Sadat Madani, Nika Mehraban, Ehsan Moudi, Ali Bijani

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 143-148

Introduction: The aim of this study was to evaluate the root canal morphology of mandibular first and second molars using cone-beam computed tomography (CBCT) in northern Iranian population and also to indicate the thinnest area around root canals. Methods and Materials: We evaluated CBCT images of 154 first molars and 147 second molars. By evaluating three axial, sagittal and coronal planes of each tooth we determined the number of root canals, prevalence of C-shaped Melton types, and prevalence of Vertucci configuration and inter orifice distance. Also the minimum wall thickness of root canals was determined by measuring buccal, lingual, distal and mesial wall thicknesses of each canal in levels with 2 mm intervals from apex to orifice. Results: Amongst 154 first mandibular molars, 149 (96.7%) had two roots, 3 (1.9%) had three roots and 2 (1.2%) had C-shaped root configuration. Of 147 second mandibular molars, 120 (81.6%) had two roots, 1 (0.6%) had three roots and 26 (17.6%) had C-shaped roots. There was no significant difference in the prevalence of Vertucci’s type between two genders. The most common configuration in mesial roots of first and second molars were type IV (57%-42.9%) and type II (31.5%-28%). Mesial and distal walls had the most frequency as the thinnest wall in all levels of root canals with mostly less than 1 mm thickness. In second molars the DB-DL inter orifice distance and in first molars the MB-ML distance were the minimum. MB-D in first molars had the maximum distance while ML-DL, MB-DB and ML-D had the same and maximum distance in second molars. Conclusion: Vertucci’s type IV and type I were the most prevalent configurations in mesial and distal roots of first and second mandibular molars and the thickness of thinnest area around the canals should be considered during endodontic treatments.

Keywords: Cone-Beam Computed Tomography; C-Shaped Root Canals; Mandibular First Molar; Mandibular Second Molar; Root Canal Anatomy; Root Canal Morphology

Physical Properties and Chemical Characterization of Two Experimental Epoxy Resin Root Canal Sealers

Hengameh Ashraf, Farhood Najafi, Soolmaz Heidari, Manijeh Mohammadian, Saeede Zadsirjan

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 149-156

Introduction: The aim of this in vitro study was to evaluate the setting time, flow, film thickness, solubility, radiopacity and characterization analysis of three epoxy resin based sealers including two experimental sealers and AH-26. Methods and Materials: Five samples of each material were evaluated for setting time, flow, film thickness, solubility and radiopacity according to ISO 6876 Standard. Characterization of sealers was performed under the scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Statistical evaluation was performed using the Kruskal-Wallis test. Results: In this study, AH-26 showed more radiopacity and flow compared to two other experimental sealers (P<0.05). However, both sealers had lower setting time than AH-26 (P<0.05). No statistical differences were found regarding film thickness, solubility and radiopacity (P>0.05). The characterization analysis exhibited relatively similar microstructure of AH-26 sealer to the experimental root canal sealers. Conclusion: According to the result of this study, all tested root canal sealers had acceptable properties based on ISO 6876 standard criteria.

Keywords: Epoxy Resin; Fourier Transform Infrared; Root Canal Sealer; Scanning Electron Microscopy; X-Ray Energy Dispersive Spectroscopy


Subcutaneous Reaction of Rat Tissues to Nanosilver Coated Gutta-Percha

Mohammad Ali Mozayeni, Omid Dianat, Shahin Tahvildari, Maryam Mozayani, Payam Paymanpour

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 157-161

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.

Keywords: Gutta-Percha; Inflammation; Nanosilver Coated Gutta-Percha; Subcutaneous Connective Tissues

In vitro Cytotoxicity Comparison of MTA Fillapex, AH-26 and Apatite Root Canal Sealer at Different Setting Times

Farnaz Jafari, Marzieh Aghazadeh, Sanaz Jafari, Faraz Khaki, Fahimeh Kabiri

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 162-167

Introduction: This study aimed to compare the cytotoxicity of MTA Fillapex, AH-26 and Apatite root canal sealers at different times after mixing. Methods and Materials: In this in vitro study, MTA Fillapex, AH-26 and Apatite root canal sealer were spilled uniformly by 40 µm mesh in a 96-well plate. Then, human fetal foreskin fibroblast cell line (HFFF2) were added to each sealer cell culture medium. Cytotoxicity was measured using MTT assay after 24, 48 and 72 h and seven days. Multiple comparisons were done using analysis of variances (ANOVA) and Scheffe’s post hoc test. Results: All studied sealers exhibited severe cytotoxicity (more than 70%) except for Apatite sealer (95%) at 48 h after mixing. Cytotoxicity of MTA Fillapex and AH-26 were similar (P>0.05) at 24, 48 and 72 h and 7 days after mixing of sealers. Cytotoxicity of MTA Fillapex and Apatite root canal sealer, at 24 and 48 h, were significantly different (P=0.003 and P=0.000, respectively); MTA Fillapex was more cytotoxic. However in 72 h and 7 days after mixing, the difference was not significant (P>0.05). At 24 and 48 h after mixing, AH-26 was more cytotoxic (P=0.002 and P=0.000, respectively). Same as above at 72 h and 7 days after mixing, their cytotoxicity were similar (P>0.05). Conclusion: Overall cytotoxicity of all studied materials were severe. However, it was observed that the cytotoxicity of MTA Fillapex, AH-26 and Apatite root canal sealer decreased over time. Apatite root canal sealer exhibited the least cytotoxicity. Cytotoxicity of MTA Fillapex and AH-26 were similar at different time intervals.

Keywords: Cytotoxicity; MTT Assay; Root Canal Sealer

Effect of Intra-Canal Calcium Hydroxide Remnants on the Push-Out Bond Strength of Two Endodontic Sealers

Sholeh Ghabraei, Behnam Bolhari, Fatemeh Yaghoobnejad, Naghmeh Meraji

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 168-172

Introduction: The aim of this study was to evaluate the effect of intra-canal calcium hydroxide (CH) remnants after ultrasonic irrigation and hand file removal on the push out bond strength of AH-26 and EndoSequence Bioceramic sealer (BC Sealer). Methods and Materials: A total of 102 single-rooted extracted human teeth were used in this study. After root canal preparation up to 35/0.04 Mtwo rotary file, all the specimens received CH dressing except for 34 specimens in the control group. After 1 week, the specimens with CH were divided into 2 groups (n=34) based on the CH removal technique; i.e. either with ultrasonic or with #35 hand file. Then specimens were divided into two subgroups according to the sealer used for root canal obturation: AH-26 or BC Sealer. After 7 days, 1 mm-thick disks were prepared from the middle portion of the specimens. The push out bond strength and failure mode were evaluated. Data were analyzed by the two-way ANOVA and Tukey’s post hoc tests. Results: The push out bond strength of both sealers was lower in specimens receiving CH. These values were significantly higher when CH was removed by ultrasonic (P<0.05). The dominant mode of failure in all subgroups was of mixed type except for the BC Sealer specimens undergoing CH removal with hand file which dominantly exhibited adhesive mode of failure. Conclusion: CH remnants had a negative effect on the push out bond strength of AH-26 and BC Sealer. Ultrasonic irrigation was more effective in removing CH.

Keywords: AH-26; Calcium Hydroxide; Endosequence BC Sealer; Push-Out Bond Strength

Influence of Root Canal Curvature on the Accuracy of Root ZX Electronic Foramen Locator: An In Vitro Study

Masoud Saatchi, Shiva Iravani, Mehrdad Akhavan Khaleghi, Amin Mortaheb

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 173-178

Introduction: The aim of this in vitro study was to evaluate the correlation between accuracy of Root ZX electronic foramen locator and root canal curvature. Methods and Materials: One hundred and ten extracted mandibular molars were selected. Access cavity was prepared and coronal enlargement of mesiobuccal canal was performed. A #10 Flexofile was inserted into the mesiobuccal canal, and a radiography was taken to measure the degree of curvature by Schneider's method. The actual working length (AWL) was defined by inserting the file until its tip could be observed at a place tangential to the major apical foramen and then 0.5 mm was subtracted from this measurement. For the electronic working length (EWL) measurement, the apical 3 or 4 mm of the root was embedded in alginate as the electrolyte material. The file was inserted into the root canal to the major foramen, until the APEX reading was shown on the electronic device and then pulled back until the visual display showed the 0.5-mm mark. The AWL was subtracted from the EWL to define the distance between the file tip and the point 0.5 mm coronal to the major apical foramen. Data were analyzed using the Pearson’s correlation coefficient. Results: The accuracy of Root ZX within ±0.1 mm and ±0.5 mm was 38.2% and 94.6%, respectively. There was no correlation between the distance from the EWL to the AWL and the degree of root canal curvature (r=0.097, P=0.317). Conclusion: Root canal curvature did not influence the accuracy of Root ZX foramen locator.

Keywords: Accuracy; Curved Root Canals; Electronic Apex Locator; Working Length

Effect of Field Of View on Detection of External Root Resorption in Cone-Beam Computed Tomography

Yaser Safi, Sahar Ghaedsharaf, Alireza Aziz, Sepanta Hosseinpour, Hamed Mortazavi

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 179-184

Introduction: Conventional methods for diagnosis of external root resorption (ERR) are based on clinical findings and x-ray observations which are not appropriate for early diagnosis. The present study assessed the effect of different sizes and field of views (FOVs) in the diagnosis of simulated external root resorption by cone-beam computed tomography (CBCT). Methods and Materials: In this diagnostic in vitro trial, 100 human extracted mandibular central incisors were collected and marked in 3 apical, middle and coronal areas. Cavities with different sizes were created in buccal and lingual surfaces of each area. Following this procedure, CBCT images were taken in 2 different 6 × 6 cm and 12 × 8 cm FOVs with the same voxel size of 0.2 mm. Absence or presence of cavities in CBCT images were assigned by 3 radiologists and compared with gold standard results which were obtained by measurement of the size of cavities using a digital caliper. Sensitivity and specificity values, positive predictive value (PPV) and negative predictive value (NPV), AZ value and Kappa values were calculated and reported. Results: Amounts of sensitivity in 6 × 6 cm FOV with voxel size of 0.2 mm for small, medium and large cavities were 95.93%, 96.03% and 97.1%, respectively. Amounts of sensitivity in 12 × 8cm FOV with the same voxel size for small, medium and large cavities were noted as 94.4%, 96.03% and 98.5%, respectively. However, specificity in FOV of 6 × 6 cm and FOV of 12 × 8 cm was calculated as 93.03% and 90.83%, respectively. Conclusion: Both used FOVs show nearly same performances in the case of detection of ERR; therefore, smaller FOV should be preferably used for detection of ERR in order to decrease the amount of imposed radiation dose given to patients.

Keywords: Cone-Beam Computed Tomography; External Root Resorption; Field of View

Efficacy of Different Root Canal Irrigants on Smear Layer Removal after Post Space Preparation: A Scanning Electron Microscopy Evaluation

Rahele Mirseifinejad, Mehdi Tabrizizadeh, Abdolrahim Davari, Fateme Mehravar

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 185-190

Introduction: Effective durable adhesion between post material and dentine using resin cements is essential for longevity of restoration. The aim of this in vitro study was to compare the effect of different irrigants on smear layer removal after post space preparation. Methods and Materials: A total of 75 extracted anterior human teeth were selected. The canals were instrumented by rotary system and then were filled. After preparing the post space, teeth were divided into 5 groups according to irrigants: 17% EDTA; 17% EDTA+2% CHX; 5.25% NaOCl; 17% EDTA+5.25% NaOCl; and saline. The canals were irrigated with 5 cc of each irrigants for 1 min. Specimens were examined with scanning electron microscopy (SEM). Hulsmann’s score was used for marking of smear layer removal at coronal, middle and apical thirds of post space. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. Results: The results revealed that subsequent use of 17% EDTA+5.25% NaOCl was more effective than the other groups in smear layer removal. No statistical difference was found among different levels of root canal within each group. Conclusion: It can be concluded that 17% EDTA+5.25% NaOCl could be an effective irrigant for smear layer removal after post space preparation.

Keywords: Post Space; Root Canal Irrigant; Scanning Electron Microscopy; Smear Layer

Scanning Electron Microscopy and Energy-Dispersive X-Ray Microanalysis of Set CEM Cement after Application of Different Bleaching Agents

Mohammad Samiei, Maryam Janani, Amin Vahdati, Yalda Alemzadeh, Mahmoud Bahari

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 191-195

Introduction: The present study evaluated the element distribution in completely set calcium-enriched mixture (CEM) cement after application of 35% carbamide peroxide, 40% hydrogen peroxide and sodium perborate as commercial bleaching agents using an energy-dispersive x-ray microanalysis (EDX) system. The surface structure was also observed using the scanning electron microscope (SEM). Methods and Materials: Twenty completely set CEM cement samples, measuring 4×4 mm2, were prepared in the present in vitro study and randomly divided into 4 groups based on the preparation technique as follows: the control group; 35% carbamide peroxide group in contact for 30-60 min for 4 times; 40% hydrogen peroxide group with contact time of 15-20 min for 3 times; and sodium perborate group, where the powder and liquid were mixed and placed on CEM cement surface 4 times. Data were analyzed at a significance level of 0.05 through the one Way ANOVA and Tukey’s post hoc tests. Results: EDX showed similar element distribution of oxygen, sodium, calcium and carbon in CEM cement with the use of carbamide peroxide and hydroxide peroxide; however, the distribution of silicon was different (P<0.05). In addition, these bleaching agents resulted in significantly higher levels of oxygen and carbon (P<0.05) and a lower level of calcium (P<0.05) compared to the control group. SEM of the control group showed plate-like and globular structure. Sodium perborate was similar to control group due to its weak oxidizing properties. Globular structures and numerous woodpecker holes were observed on the even surface on the carbamide peroxide group. Conclusion: The mean elemental distribution of completely set CEM cement was different when exposed to sodium perborate, carbamide peroxide and hydrogen peroxide.

Keywords: Bleaching Agents; Calcium-Enriched Mixture; Energy-Dispersive X-Ray Microanalysis; Scanning Electron Microscopy

Effect of Blood Exposure on Push-Out Bond Strength of Four Calcium Silicate Based Cements

Kazem Ashofteh Yazdi, Behnam Bolhari, Tohid Sabetmoghaddam, Naghmeh Meraji, Mohammad Javad Kharazifard

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 196-200

Introduction: The purpose of this study was to compare the push-out bond strength of white ProRoot Mineral Trioxide Aggregate (MTA), Biodentine, calcium-enriched mixture (CEM) cement and Endosequence Root Repair Material (ERRM) putty after exposure to blood. Methods and Materials: A total of 96 root dentin slices with a standardized thickness of 1.00±0.05 mm and standardized canal spaces were randomly divided into 4 main experimental groups (n=24) according to the calcium silicate based cement (CSC) used: white ProRoot MTA, CEM Cement, ERRM Putty and Biodentine. Specimens were exposed to whole fresh human blood and then subdivided into two subgroups depending on the exposure time (24 or 72 h). Push-out bond strength was measured using a universal testing machine. Failure modes were examined under a light microscope under ×10 magnification. Data were analyzed using the two-way ANOVA test. Results: Biodentine exhibited the highest values regardless of the exposure time. The lowest push-out strength values were seen in white ProRoot MTA and CEM cement in both post exposure times. After exposure to blood, the push-out bond strength of all materials increased over time. This increase was only statistically significant in white ProRoot MTA and ERRM specimens. The dominant failure mode in all CSCs was the adhesive mode. Conclusion: Biodentine showed the highest values of push-out bond strength and may be better options for situations encountering higher dislocation forces in a short time after cement application.

Keywords: Biodentine; Blood; Calcium-Enriched Mixture Cement; Endosequence Root Repair Material; Mineral Trioxide Aggregate

Students’ Knowledge Comprehension after Implementation of Live Conventional Demonstration, Video Teaching and Video-Assisted Instruction Methods in Endodontic Practice

Nahid Mohammadzadeh Akhlaghi, Zohreh Khalilak, Mehdi Vatanpour, Amirabbas Moshari, Saman Ghaffari, Mohammad Sadegh Namazikhah

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 201-204

Introduction: Video-assisted clinical instruction (VACID) has been found to be a beneficial teaching tool for various fields in dentistry. The aim of this interventional study was to compare the efficacy of live conventional demonstration (CD), video teaching, and VACID (video with explanation) methods in teaching of root canal treatment to undergraduate dental students. Methods and Materials: Forty-two undergraduate senior dental students participated in this study. The students experienced this course for the first time and were randomly divided into three groups (n=14). Group A attended live CD on a patient; group B watched a professionally produced demonstration video without any verbal explanation during 1 h; and finally group C watched the same video alongside live explanation by a mentor during the 1.5 h (VACID). The whole process was performed by an experienced endodontist on maxillary central incisors. All of The students carried out a multiple choice question exam to evaluate their comprehension. The mean score of the experimental groups were compared using ANOVA test and multiple comparisons were carried out with Tamhane test. The level of significance was set at 0.05. Results: There was significant difference among three groups according to the ANOVA test (P<0.05). Group VACID had the highest mean scores. There was significant difference between the groups VACID and VT (P=0.011); no significant differences were found in other inter-group comparisons. Conclusion: According to the results, VACID may improve the quality of endodontic training in undergraduate dental students.

Keywords: Conventional Education; Endodontic Treatment; Knowledge; Performance; Video-Assisted Clinical Instruction

Comparative Antimicrobial Efficacy of Eucalyptus Galbie and Myrtus Communis L. Extracts, Chlorhexidine and Sodium Hypochlorite against Enterococcus Faecalis

Mahdieh Nourzadeh, Arezu Amini, Farzaneh Fakoor, Maryam Raoof, Fariba Sharififar

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 205-210

Introduction: The aim of this study was to evaluate the antimicrobial effect of Eucalyptus galbie and Myrtus communis L. methanolic extracts, chlorhexidine (CHX) and sodium hypochlorite (NaOCl) on Enterococcus faecalis (E. faecalis) as the predominant species isolated from infected root canals. Methods and Materials: One hundred twenty mandibular premolars were randomly divided into 8 groups: Eucalyptus galbie (E. galbie) 12.5 mg/mL, Myrtus communis L. (M. communis L.) 6.25 mg/mL, 0.2% CHX, %2 CHX, 2.5% NaOCl, 5.25% NaOCl, positive and negative control group. Sampling was performed using paper points (from the root canal space lumen) and Gates-Glidden drills (from the dentinal tubules); then colony forming units (CFU) were counted and analyzed using the Kruskal-Wallis test, followed by Mann Whitney U test. The level of significance was set at 0.05. Results: All irrigants reduced more than 99% of bacteria in root canal. In the presence of M. communis L. and E. galbie, the bacterial count in dentin were significantly more than CHX and NaOCl groups (P<0.05) except 0.2% CHX in 200 µm and 400 µm depths (P>0.05). Conclusion: Although 5.25% NaOCl was the most effective irrigant, all agents exerted acceptable antimicrobial activity against E. faecalis.

Keywords: Antibacterial Agent; Eucalyptus; Myrtus; Root Canal Therapy

In Vitro Microleakage of Mineral Trioxide Aggregate, Calcium-Enriched Mixture Cement and Biodentine Intra-Orifice Barriers

Fatemeh Ramezanali, Sasan Aryanezhad, Fatemeh Mohammadian, Fatemeh Dibaji, Mohammad Javad Kharazifard

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 211-215

Introduction: This in vitro study compared the coronal microleakage of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement and Biodentine as intra-orifice barriers. Methods and Materials: The study was conducted on 76 extracted single-canal human teeth. Their root canals were prepared using ProTaper rotary files and filled with gutta percha and AH-26 sealer using lateral condensation technique. Coronal 3 mm of the gutta percha was removed from the root canals and replaced randomly with MTA, CEM cement or Biodentine in the three experimental groups (n=22). A positive and a negative control group were also included (n=5). The entire root surfaces of all teeth were covered with two layers of nail varnish in such a way that only the access openings were not coated. In the negative control group, the access opening was also coated with nail varnish. All teeth were immersed in India ink and after clearing, the samples were evaluated under a stereomicroscope under ×10 magnification to assess the degree of dye penetration. The data were analyzed using the Kruskal-Wallis test. The level of significance was set at 0.05. Results: The negative control group showed no leakage while the positive control group showed significantly higher microleakage than the test groups (P>0.05). CEM cement had the lowest (0.175±0.068 mm) and MTA showed the highest dye penetration (0.238±0.159 mm) among the experimental groups; although these differences were not statistically significant (P=0.313). Conclusion: CEM cement exhibited the least microleakage as an intra-orifice barrier in endodontically treated teeth.

Keywords: Biodentine; Calcium-Enriched Mixture; Intra-Orifice Barrier; Microleakage; Mineral Trioxide Aggregate

Effect of Deep Cryogenic Treatment on Cyclic Fatigue of Endodontic Rotary Nickel Titanium Instruments

Mohammad Yazdizadeh, Masoumeh Skini, Seyyed Mohsen Hoseini Goosheh, Mansour Jafarzadeh, Milad Shamohammadi, Vahid Rakhshan

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 216-219

Introduction: Cyclic fatigue is the common reason for breakage of rotary instruments. This study was conducted to evaluate the effect of cryogenic treatment (CT) in improving the resistance to cyclic fatigue of endodontic rotary instruments. Methods and Materials: In this in vitro study, 20 RaCe and 20 Mtwo files were randomly divided into two groups of negative control and CT. CT files were stored in liquid nitrogen at -196°C for 24 h, and then were gradually warmed to the room temperature. All files were used (at torques and speeds recommended by their manufacturers) in a simulated canal with a 45° curvature until breakage. The time to fail (TF) was recorded and used to calculate the number of cycle to fail (NCF). Groups were compared using independent-samples t-test. Results: Mean NCFs were 1248.2±68.1, 1281.6±78.6, 4126.0±179.2, and 4175.4±190.1 cycles, for the Mtwo-control, Mtwo-CT, RaCe-control, and RaCe-CT, respectively. The difference between the controls and their respective CT groups were not significant (P>0.3). The difference between the systems was significant. Conclusion: Deep CT did not improve resistance to cyclic fatigue of the evaluated rotary files.

Keywords: Cryogenic Treatment; Cyclic Fatigue; Instrument Fracture; Rotary Nickel Titanium Files

In Vitro Cytotoxicity of a New Nano Root Canal Sealer on Human Gingival Fibroblasts

Maryam Javidi, Parisa Dastmalchi, Mina Zarei, Maryam Shayani Rad, Ahmad Ghorbani

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 220-225

Introduction: The aim of this in vitro study was to evaluate the cytotoxicity of a new nano zinc-oxide eugenol (NZOE) sealer on human gingival fibroblasts (HGFs) compared with Pulpdent (micro-sized ZOE sealer) and AH-26 (resin-based sealer). Methods and Materials: The Pulpdent, AH-26, and NZOE sealers were prepared and exposed to cell culture media immediately after setting, and 24 h and one week after setting. Then, the primary cultured HGFs were incubated for 24 h with different dilutions (1:1 to 1:32) of each sealer extract. Cell viability was evaluated by methyl thiazolyl diphenyl tetrazolium bromide (MTT) assay. The results were compared using two-way analysis of variance followed by Tukey’s post hoc test. The level of significance was set at 0.05. Results: All sealer extracts, up to 32 times dilutions, showed cytotoxicity when exposed to HGF immediately after setting. The extracts obtained 24 h or one week after setting showed lower cytotoxicity than extracts obtained immediately after setting. At all setting times, NZOE showed lower cytotoxicity than Pulpdent and AH-26. While one-week extracts of NZOE had no significant effect on the viability of HGF at dilutions 1:4 to 1:32, both Pulpdent and AH-26 decreased the cell viability at dilutions of 1:4 and 1:8. Conclusion: NZOE exhibited lower cytotoxicity compared to Pulpdent and AH-26 on HGF and has the potential to be considered as a new root canal filling material.

Keywords: Cytotoxicity; Human Gingival Fibroblast; MTT assay; Nano; Sealer

Pulp Response following Direct Pulp Capping with Dentin Adhesives and Mineral Trioxide Aggregate; An Animal Study

Ali Akhavan, Farahnaz Arbabzadeh, Majid Bouzari, Sayed Mohammad Razavi, Amin Davoudi

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 226-230

Introduction: Pulp vitality and its continuous dentin prodution are essential for long-term success of direct pulp capping (DPC). The aim of present study was to evaluate the histopathological response of the canine pulp following DPC using either different dentin adhesive resins (DAR), calcium hydroxide (CH) or mineral trioxide aggregate (MTA). Methods and Materials: DPC was done on 72 dog’s teeth using 6 types of dental materials (n=12) (4 types of DAR, white MTA and CH). Therefore, six healthy dogs were anesthetized and 2 teeth from each dog were allocated to either type of mentioned DPC agents. The dental pulps were exposed mechanically by drilling in the center of class V cavities. The different types of capping materials included DARS (Clearfil S3 Bond, Optibond FL, Single Bond and Clearfil SE Bond), white MTA and CH. After 7, 21 and 63 days, two dogs were euthanized in each interval. Microscopic evaluations were done according to following criteria: intensity of inflammation, presence of necrosis and formation of hard tissue. The recorded data were analyzed by the Kruskal-Wallis, Friedman, Cochran’s and Fisher’s exact tests using SPSS software version 12 at significant level of 0.05. Results: No significant differences were found regarding necrosis among DPC materials (P>0.05). However, MTA caused higher amount of hard tissue formation after 63 days in comparison with 21 days. Conclusion: MTA provided the highest degree of hard tissue formation after 63 days. However, further studies should be performed for administering a definitive material.

Keywords: Dentin Adhesive Systems; Direct Pulp Capping; Mineral Trioxide Aggregate

In Vitro Sealing Properties of Calcium-Enriched Mixture and Mineral Trioxide Aggregate Orifice Barriers during Intra-Coronal Bleaching

Negar Moghadam, Amir Ardalan Abdollahi, Hoda Aghabalayi Fakhim, Zahra Borna

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 231-235

Introduction: This study aimed at evaluating the sealing properties of calcium-enriched mixture (CEM) compared to mineral trioxide aggregate (MTA) as a cervical barriers in intra-coronal bleaching. Methods and Materials: In this in vitro study, endodontic treatment was performed on 60 extracted human incisors and canines without canal calcification, caries, restorations, resorption or cracks. The teeth were then randomly divided into two experimental groups and two control groups (n=15). Then, CEM cement and MTA were applied as 3-mm intra-orifice barriers in the test groups; a mixture of sodium perborate and 30% hydrogen peroxide bleaching agents were placed within the pulp chamber for one week. Dye penetration method was used to evaluate the sealing ability of agents. Statistical analysis was performed using SPSS software. The Kendall coefficient was used to evaluate inter-observer agreement. The chi-squared test was used for statistical analysis. Results: The results showed that the penetration rates of CEM and MTA were the same as positive control group, with no significant differences (P=0.673 and P=0.408, respectively). However, there was a significant difference between the negative control group and CEM and MTA groups (P=0.001 for both groups). In addition, the sealing ability of MTA and CEM cement were not significantly different (P=0.682). Conclusion: During intra-coronal bleaching procedures CEM cement can be used as a cervical barrier with sealing properties comparable to that of MTA.

Keywords: Calcium-Enriched Mixture Cement; Cervical Barrier; Intra-Coronal Bleaching; Mineral Trioxide Aggregate

Radiographic Quality of Root Canal Obturation Performed By Fifth Year Students of Hamadan Dental School

Amir Eskandarloo, Hamed Karkehabadi, Seyedeh Zeinab Hoseini Hashemi, Masoumeh Ahmadi, Seyedeh Sareh Hendi

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 236-241

Introduction: The aim of this study was to assess the radiographic technical quality of root canal therapy performed by fifth year students of Dental School of Hamadan University of Medical Sciences from 2015 to 2016. Methods and Materials: Four hundred and seventy records of root canal therapies were evaluated. Records with graphies taken as initial, master apical file (MAF), master apical cone (MAC) and final radiographs were included in the study and records of patient younger than 16 years and older than 68 years were excluded from further investigations. Lastly, 432 teeth were selected. Obturation length, canal tapering, quality and density of filling material were the variables investigated in the present study. Two independent investigators examined the radiographies using a magnifying lens (×2) and x-ray viewer. Data were analyzed using chi-square test. Results: The technical quality of root filling performed by undergraduate dental students was classified as acceptable in 10.4% of cases. Moreover, 70.8% of teeth had adequate filling, 17.1% were underfilled and 12% were overfilled. The three groups were significantly different in terms of working length and taper quality. One hundred ninety four (44.9%) records had adequate taper and 109 (25%) records had adequate density. There was a significant association between teeth location and the length of obturation so that the probability of a successful treatment was higher in maxillary teeth. Furthermore, the rate of a proper length of obturation was higher among incisors than that of premolars and molars. Conclusion: The technical quality of root canal therapy performed by dental students in Hamadan University of medical sciences is not as acceptable as it should be. One of the most important factors in this regard is a high student/professor ratio.

Keywords: Dental Students; Quality Control; Root Canal Obturation; Root Canal Therapy

Introduction: Gutta-percha must be removed from the root canal space during retreatment to ensure a more favorable outcome. The aim of this study was to compare the efficacy of hand instruments, RaCe and RaCe plus XP-endo finisher instruments in removal of gutta-percha from root canal walls during retreatment. Methods and Materials: Thirty single-rooted premolars were prepared, obturated, and divided into three groups according to retreatment method; in group 1, retreatment was carried out by hand instruments, while in groups 2 and 3 retreatment was done using RaCe rotary files alone or accompanied by XP-endo finisher instruments, respectively. After retreatment, teeth were sectioned longitudinally and photographic images were taken. The amount of remaining gutta-percha in coronal, middle and apical thirds was quantified using Image J software. The two-way ANOVA and post hoc Tukey’s tests were used to analyze data. The level of significance was set at 0.05. Results: RaCe cleaned the apical third significantly better than hand instrumentation. In the coronal third, RaCe+XP-endo finisher was more effective than RaCe. RaCe+XP-endo finisher was more effective than hand instrumentation in the entire root canal. The amount of remaining gutta-percha was the least in the apical part and increased toward the coronal part with the use of XP-endo finisher (P<0.05). Conclusion: Rotary instrumentation was more effective in removing gutta-percha from the canal walls. Furthermore, use of XP-endo finisher file resulted in cleaner canal walls and was more effective in removing gutta-percha from the coronal toward the apical part of the canal.

Keywords: Gutta-Percha Removal; RaCe; Root Canal Retreatment; XP-endo Finisher

Case Report

Endodontic Management of Open Apex Teeth Using Lyophilized Collagen Sponge and MTA Cement: Report of Two Cases

Miriam Graziele Magro, Milton Carlos Kuga, Weber Adad Ricci, Kátia Cristina Keine, Mateus Rodrigues Tonetto, Suellen Linares Lima, Alvaro Henrique Borges, Lauriê Garcia Belizário, Matheus Coelho Bandeca

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 248-252

Teeth with open apices, such as in immature teeth or those with apical root resorption are clinical cases with difficult immediate resolution. With the use of mineral trioxide aggregate (MTA) in dentistry, it was possible to optimize the treatment time of these cases by immediate placement of apical plug and the root canal filling. However, some negative effects can occur if MTA is extruded beyond the apex. To avoid this accident, it has been recommended to use of an apical matrix prior to placement of MTA. This study reports two clinical cases of apical plug placement in teeth with pulp necrosis and open apices. One case had an immature apex due to dental trauma and the other case had apical resorption due to the presence of endodontic infection in the root canal. MTA apical plug with approximately 4 mm thickness, was placed in the apical zone of the root and immediately the canal was obturated with gutta-percha and endodontic sealer. Follow-up evaluations showed clinical and radiographic evidence of success.

Keywords: Apex; Collagen; Endodontics; Mineral Trioxide Aggregate

Nonsurgical Management of a Large Periapical Lesion: A Case Report

Sajedeh Ghorbanzadeh, Hengameh Ashraf, Sepanta Hosseinpour, Fatemeh Ghorbanzadeh

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 253-256

This case report describes the non-surgical management of a large cyst-like periapical lesion in the mandible of a 16-year-old female with the chief complaint of periodic swelling and pus drainage from the mandibular anterior region gingivae with no history of pain and traumatic accident in this area. Both mandibular central incisors had extensive caries. Root canals of both mandibular central incisors were filled with calcium hydroxide. After 10 days, endodontic therapy was carried out on both teeth. Clinical and radiographic re-evaluations at 3 and 12 months revealed progressing bone healing. This case report shows that appropriate diagnosis in combination with root canal treatment as a conservative non-surgical approach can lead to complete healing of large lesions without invasive treatments.

Keywords: Mandibular Incisor; Nonsurgical Endodontic Therapy; Radicular Cyst

Management of Perforating Idiopathic Internal Root Resorption

Dalia Abdullah, Farah Eziana Hussein, Huwaina Abd Ghani

Iranian Endodontic Journal, Vol. 12 No. 2 (2017), 28 March 2017 , Page 257-260

This case report describes the endodontic treatment of an idiopathic perforated internal root resorption. A 24-year-old male Malay patient presented with internal root resorption of two of his anterior teeth. The medical history was non-contributory and he had no history of traumatic injury or orthodontic treatment. Cone-beam computed tomography (CBCT) determined the nature, location and severity of the resorptive lesion. Non-surgical root canal treatment of tooth #22 and combined non-surgical and surgical approach for tooth #11 were carried out using mineral trioxide aggregate (MTA) as the filling material. The clinical and radiographic examination three years after completion of treatment revealed evidences of periapical healing. The appropriate diagnosis and the treatment of internal root resorption allowed good healing of these lesions and maintained the tooth in function for as long as possible.

Keywords: Cone-Beam Computed Tomography; Idiopathic; Internal Root Resorption; Mineral Trioxide Aggregate

Root canal therapy (RCT) is a common and successful treatment for irreversible pulpitis due to carious pulp exposure in mature permanent teeth. However, it is often an expensive procedure, may require multiple appointments, and requires a high level of training and clinical skill, specifically in molars. Uninsured patients, low-income patients, and patients with limited access to specialist care often elect for extraction of restorable teeth with irreversible pulpitis. There is a need for an alternative affordable treatment option to preserve their teeth and maintain chewing function. A case of pulpotomy using calcium-enriched mixture (CEM) cement in two maxillary molars (#14 and 15) in a healthy 36-year-old patient is presented. Both teeth were diagnosed with symptomatic hyperplastic/irreversible pulpitis. Patient did not have dental insurance, was unable to afford RCT, and refused to extract the teeth. CEM pulpotomy and amalgam build-ups were done as an alternative to extraction. At 2-year recall, both teeth were functional with no signs/symptoms of inflammation/infection. Periapical radiographs and 3D images showed normal PDL around all roots. Pulpotomy with CEM biomaterial might be a viable alternative to tooth extraction for mature permanent teeth with hyperplastic/irreversible pulpitis, and can result in long-term tooth retention and improved oral health.

Keywords: Calcium-Enriched Mixture; Hyperplastic Pulpitis; Irreversible Pulpitis; Mineral Trioxide Aggregate; Permanent Teeth; Pulp Polyp; Pulpotomy; Vital Pulp Therapy

Letter to the Editor