Iranian Endodontic Journal

Introduction: The aim of this study was to evaluate the clinical and histological status of the pulp in sound human premolars after direct pulp capping (DPC) with four different DPC methods/materials. Methods and Materials: This study was conducted on eight volunteers who had to extract four first premolars due to orthodontic treatment. Subsequent to tooth isolation, standardized class I occlusal cavities were prepared and the buccal pulp horns were exposed. Then four different protocols of DPC were applied randomly: group A (control); calcium hydroxide lining paste (Dycal), group B; ProRoot MTA (standard double-visit method), group C; ProRoot MTA (single-visit method) and group D; calcium hydroxide injectable paste (Multi-Cal). The cavities were then restored and the patients were put on a six-week clinical follow-up and by the end of this period the teeth were extracted for histological evaluation. Data were analyzed with the Kruskal Wallis test and the level of significance was set at 0.05. Results: In terms of clinical symptoms and formation of hard tissue bridge (HTB), no significant differences were found between groups A, B and C (P>0.05); however, group D’s results were significantly different as they exhibited minimal HTB formation and excessive sensitivity (P<0.05). Inflammation was significantly lower in group B (P>0.05). Conclusion: Application of MTA during a single-visit protocol of DPC was clinically and histologically as successful as the standard double-visit method but the routine use of Multi-Cal as pulp capping material is questionable and should be reconsidered.

Introduction: Assessment of cellular cytotoxicity is a regular method for evaluating the biocompatibility of novel materials. In a recent study, 5% fluoride varnish (Duraflur) has shown reasonable sealing ability and coverage of root canal walls when used as a sealer. The aim of the present study was to compare cytotoxicity of Duraflur varnish with two popular commonly used root canal sealers (AH-Plus and AH-26) on human gingival fibroblasts (HGF). Methods and Materials: The HGFs were incubated with different concentrations (1/2, 1/4, and 1/8) of AH-plus, AH-26, and Duraflur varnish for 24 h. The percentage of cell viability was assessed with methyl-thiazol-tetrazolium (MTT) assay. The data was analyzed using the one-way ANOVA followed by Student-Newman-Keuls test. The level of significance was set at 0.001. Results: MTT assay showed that higher concentrations of the tested materials resulted in lower viability of HGFs. AH-Plus showed significantly greater cell viability compared to AH-26 at all dilutions (P<0.001); however, no significant difference was found between Duraflur and AH-Plus in terms of cell viability at 1/8 dilution (P>0.001). Duraflur showed significantly higher cell viability compared to AH-26 except at 1/2 dilution (P<0.001). Conclusion: Although Duraflur varnish had better biocompatibility compared to AH-26, it should still be evaluated with further biocompatibility tests such as intraosseous and subcutaneous implantation.

Introduction: The aim of this study was to evaluate the retreatability of root canals obturated with gutta-percha (GP) and three different endodontic sealers [iRoot SP (bioceramic sealer), MTA Fillapex (MTA-based sealer) and AH-26 (epoxy resin-based sealer)] using the ProTaper Universal Retreatment (PTR) system. Methods and Materials: Forty extracted single-rooted human teeth were prepared with universal ProTaper files up to F4 (40/0.06). Specimens were randomly divided into four groups according to obturation technique/material: single-cone GP/AH-26, lateral compaction of GP/AH-26, single-cone GP/iRoot SP, and single-cone GP/MTA Fillapex. Root fillings were removed with PTR. The time taken to reach the working-length (TWL) was recorded. Roots were longitudinally sectioned and each half was evaluated using a stereomicroscope. Three observers scored each third of all specimen. Obtained data were analyzed using the Kruskal-Wallis, Mann-Whitney U, Welch and Games-Howell tests. The level of significance was set at 0.05. Results: In single-cone GP/MTA Fillapex group the TWL was significantly shorter. The remnant of filling material in the apical and middle thirds of groups was similar and higher than the coronal thirds. Conclusion: None of the tested sealers were completely removed from the root canal system

Introduction: This study compared the apical sealing ability of a bioceramic based root canalrepair filling material (iRoot FS) with mineral trioxide aggregate (MTA). Methods and materials: Forty single-canal teeth were prepared and randomly divided into two experimental groups (n=18) and two control groups (n=2). Teeth in experimental groups were retrofilled with either MTA or iRoot FS. After setting of the retrofillings, all roots were exposed to 0.2% Rhodamine B solution for 48 h and were then washed for 12 h before longitudinal sectioning. The extent of dye penetration was measured under fluorescence microscope. Results: The mean leakage values in MTA and iRoot FS samples were 35.63 and 35.15 µm, respectively. There was no significant differences between the two materials in this regard (P=0.584). Conclusion: According to dye leakage results, iRoot FS had similar apical sealing ability to MTA and might be considered as a promising root-end filling material.

Introduction: The aim of this experimental laboratory study was to evaluate the effect of different mixing and placement techniques on compressive strength (CS) of calcium-enriched mixture (CEM) cement. Methods and Materials: CEM powder was mixed with its liquid either by hand mixing or amalgamator mixing. The mixture was loaded to cylindrical acrylic molds with 6.0±0.1 mm height and 4.0±1 mm diameter. Half of the specimens in each group were selected randomly and ultrasonic energy was applied to them for 30 sec. All samples were incubated for 7 days at 37^°C. The CS test was performed by means of a universal testing machine. The data were analyzed by the two-way analysis of variance (ANOVA) and Tukey’s post hoc tests. The level of significance was set at 0.05. Results: The maximum CS was seen in the amalgamator-mixed samples that did not receive ultrasonic agitation. The CS value of amalgamator-mixed samples was significantly higher than manually-mixed ones (P=0.003). Ultrasonic vibration did not change the CS of specimens. Conclusion: According to the results, mixing with amalgamator increases the CS of CEM cement, while ultrasonic vibration had no positive effect

Introduction: Nano-hydroxyapatite (NHA) has been used for regeneration of osseous defects. Calcium-enriched mixture (CEM) cement is also used for various dental treatments. This trial compared the efficacy of NHA and CEM cement for direct pulp capping (DPC) of sound primary teeth. Methods and Materials: In this randomized clinical trial with split-mouth design, after attaining informed consent, 20 sound primary canines scheduled for orthodontic extraction, were selected. After mechanical pulp exposure, the exposed site was capped with either NHA or CEM cement and then immediately restored with glass-ionomer and resin composite. The teeth were extracted after two months and examined histologically. Parameters of hard tissue bridge (HTB) formation, its type and quality as well as pulpal inflammation scores were compared between the two experimental groups. The data were analyzed using the Mann Whitney U and Fisher’s exact test. The level of significance was set at 0.001. Results: All CEM specimens showed inflammation score of 0 (less than 10%). However, in NHA group, inflammation scores of 0 (less than 10%), 1 (10%-30%) and 2 (30%-50%) were observed in 2 (20%), 4 (40%) and 4 (40%) specimens, respectively (P<0.001). HTB was formed in all CEM specimens while it was developed in 2 specimens of NHA (20%; P<0.001). All CEM specimens showed normal pulp; only two cases in NHA group (20%) demonstrated uninflamed normal pulp. Conclusion: CEM cement was superior to NHA as a DPC agent in terms of HTB formation and pulp inflammation scores. It is a suitable material for the DPC of primary teeth.

Introduction: The aim of this study was to gather information on the materials and methods employed in root canal treatment (RCT) by general dental practitioners (GDPs) in Iran. Methods and Materials: A questionnaire was distributed among 450 dentists who attended the 53^th Iranian Dental Association congress. Participants were asked to consider demographic variables and answer the questions regarding the materials and methods commonly used in RCT. Descriptive statistics were given as absolute frequencies and valid percentages. The chi-square test was used to investigate the influence of gender and the years of professional activity for the employed materials and techniques. Results: The response rate was 84.88%. The results showed that 61.5% of the participants did not perform pulp sensitivity tests prior to RCT. Less than half of the general dental practitioners (47.4%) said that they would trace a sinus tract before starting the treatment. Nearly 16% of practitioners preferred the rubber dam isolation method. Over 36% of the practitioners reported using formocresol for pulpotomy. The combined approach of working length (WL) radiographs and electronic apex locators was used by 35.2% of the practitioners. Most of the respondents used K-file hand instruments for canal preparation and the technique of choice was step-back (43.5%), while 40.1% of respondents used NiTi rotary files, mostly ProTaper and RaCe. The most widely used irrigant was normal saline (61.8%). Calcium hydroxide was the most commonly used inter appointment medicament (84.6%). The most popular obturation technique was cold lateral condensation (81.7%) with 51% using zinc oxide eugenol-based sealers. Conclusions: The majority of Iranian GDPs who participated in the present survey do not comply with quality guidelines of endodontic treatment.

Introduction: Mental foramen (MF) is an important anatomic landmark in dentistry and knowledge about its variable locations (L) and type of emergence (TE), has an effect on the sufficiency of local anesthesia and safety of surgical procedures. The aim of this study was to evaluate the L and TE of this radiographic landmark as well as the presence of accessory MF, by means of cone-beam computed tomography (CBCT). Methods and Materials: In this cross sectional study, a total of 156 CBCT images were retrieved from the archive of a private radiology clinic and were then evaluated for the position of MF and its TE and the existence of accessory foramina in the body of mandible. The extracted information was compared in both genders, in both sides of mandible and among three different age groups (20-29, 30-44 and 45-59 years). The Pearson chi-square and Fisher’s Exact tests were used for statistical analysis. The level of significance was set at 0.05. Results: Second premolar was the most common anterolateral L of MF; in general, 48.7% of right and 51.9% of left MFs were located at the apex of second premolar. Anterior and straight ET were more common in right and left side, respectively. Accessory MF was present in only 8 (5.1%) of cases. Conclusion: The possible presence of accessory MF should not be overlooked for avoiding the occurrence of a neurosensory disturbance during surgery and implant insertion

Introduction: Vertical root fracture (VRF) is the longitudinal fracture of the root in endodontically treated teeth. Considering the limitations of two-dimensional radiographic images in detection of VRF and introduction of cone-beam computed tomography (CBCT), this study was designed to find the sensitivity, specificity and accuracy of CBCT and periapical (PA) radiography in detection of VRFs. Methods and Materials: This was a cross-sectional in vitro study on 80 extracted human single canal teeth including 40 maxillary and 40 mandibular teeth. After standardized endodontic treatment of the roots, VRF was induced in half of the teeth in each group, and other half were left without fracture. Teeth were inserted in dry maxillary and mandibular alveoli. PA radiographs and CBCT images were taken from the specimens. Data were analyzed with SPSS software. The McNemar test was used to evaluate the sensitivity, specificity and accuracy of images, and kappa coefficient was used to assess the degree of agreement between the observers. The level of significance was set at 0.05. Results: Sensitivity and specificity values of CBCT were 97.5% and 95%, respectively. However, for PA radiography the sensitivity and specificity were 67.5% and 92.5%, in order of appearance. Accuracy of CBCT (96.25%) and PA radiography (80%) in both jaws were significantly different (P=0.022). Two methods were not significantly different when testing specificity (P=0.298). Conclusion: This study showed that the sensitivity and accuracy of CBCT in detection of vertical root fracture are higher than periapical radiography. CBCT can be recommended to be used in detection of vertical root fractures.

Introduction: The purpose of this study was to evaluate the radiographic quality of root canal fillings by fourth-, fifth-, and sixth-year undergraduate students at Tabriz Faculty of Dentistry between 2006 and 2012. Methods and Materials: A total of 1183 root canal fillings in 620 teeth were evaluated by two investigators (and in case of disagreement by a third investigator) regarding the presence or absence of under-fillings, over-fillings and perforations. For each tooth, preoperative, working and postoperative radiographs were checked. The Pearson’s chi-square test was used for statistical evaluation of the data. Inter-examiner agreement was measured by Cohen’s kappa (k) values. The level of significance was set at 0.05. Results: Total frequencies of over-filling, under-filling and perforation were 5.6%, 20.4% and 1.9%, respectively. There were significant differences between frequencies of over- and under-fillings (P<0.05). Unacceptable quality, under- and over-fillings were detected in 27.9% of 1183 evaluated canals. Conclusion: The technical quality of root canal therapies performed by undergraduate dental students using step-back preparation and lateral compaction techniques was unacceptable in almost one-fourth of the cases.

Introduction: Microleakage can result in failure of endodontic treatment. An important characteristic of endodontic sealer is sealing ability. The aim of this experimental study was to compare the apical leakage of teeth obturated with gutta-percha and three different sealers (resin- and zinc oxide eugenol-based) with/without smear layer (SL). Materials and Methods: In this study, 100 single-rooted teeth were used after cutting off their crowns. Cleaning and shaping was carried out with step-back technique and the samples were randomly divided into three groups (n=30) which were then divided into two subgroups (n=15) according to the presence/absence of SL. Two negative and positive control groups (n=5) were also prepared. In the various groups, the canals were obturated with gutta-percha and either of the test sealers (AH-26, Adseal or Endofill). The samples were submerged in India ink for 72 h. Then they were longitudinally sectioned and observed under a stereomicroscope at 20× magnification. Data were analyzed with descriptive statistical methods and one-way ANOVA. The significance level was set at 0.05. Results: The mean penetration length of dye in AH-26, Adseal and Endofill samples were 2.53, 2.76 and 3.03 mm, respectively. The differences between three groups were not significant (P>0.05); also, the mean dye penetration in AH-26, Adseal and Endofill samples in presence or absence of the SL was not significantly different. Conclusion: AH-26, Adseal and Endofill were similarly effective in prevention of apical microleakage. Differences in the mean dye penetration between the groups with/without the SL were not statistically significant.

Introduction: The aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. Methods and Materials: Mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25^° and 35^° and radii of curvature from 5 to 9 mm, were divided into three groups (n=40). In each group the canals were instrumented with either WaveOne (W), Reciproc(R) or ProTaper (P). The time required for canal shaping and the frequency of broken instruments were recorded. The standardized pre and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analyzed using the one-way analysis of variance (ANOVA) and post-hoc Tukey’s test. The level of significance was set at 0.05. Results: Both single-instrument systems reduced the canal preparation time by approximately 50% (P<0.05). No incidence of broken instruments from single-file systems was reported; however, two F2 instruments in the P group were broken (P<0.05). Reduction in WL and straightening of canal curvature was observed in all three systems with the highest scores belonging to P system (P<0.05). No case of blockage or perforation was found during shaping in any group. Conclusion: Single-file systems shaped curved canals with substantial saving in time and a significant decrease in incidence of instrument separation, change in WL, and straightening of canal curvature.

Introduction: The aim of this study was to evaluate the effect of different mixing techniques on the pH and solubility of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM). Methods and Materials: Five samples were prepared from each biomaterial with different mixing techniques including hand-, amalgamator- or ultrasonic-mixing and were then placed in pre-weighted plastic tubes to determine their pH values. Each tube was then incubated in 10 mL deionized distilled water for 1 h at 37^ºC. An electrode was placed in the fluid in each flask at 24^ºC and the pH was recorded. In the next stage, six samples from each mixing technique/material were separately placed in glass bottles containing 50 mL of distilled water at 37^ºC for 1 h and were let dry for 1 h at 37^ºC. The samples’ weights were measured and recorded twice. The procedure was repeated at 1-, 7- and 21-day intervals. Data were analyzed with the repeated measures ANOVA (for solubility) and two-way ANOVA (for pH) and then the post-hoc Tukey’s test was done. Results: The pH of the materials was not significantly affected by mixing methods (P=0.8 for CEM and P=0.1 for MTA). The solubility of all test groups was within the acceptable range (≤3%). However, the solubility of CEM at 1- and 21-day intervals was significantly different (P=0.03 for 1 day and P=0.001 for 21 days). Different mixing techniques had significant effects on the solubility of MTA at the three time points (P=0.004, 0.003 and 0.002 for 1-, 7- and 21-day intervals, respectively). Conclusion: The pH of biomaterials was not influenced by the mixing technique and their solubility was within the acceptable range.

Introduction: The purpose of this in vitro study was to assess the antifungal activity of final canal rinse with either three concentrations of sodium hypochlorite (NaOCl) (0.5, 2.6 and 6%), two concentrations of chlorhexidine (CHX) (2% and 0.2%), MTAD, Tetraclean, Hypoclean and Chlor-Xtra on Candida albicans (C. albicans) in a human tooth model. Methods and Materials: Two hundred and thirty five extracted human maxillary central and lateral incisors were used in this study. Teeth were randomly divided into nine test groups (n=25) and positive and a negative control groups (n=5). After cleaning and shaping, teeth were contaminated with C. albicans and incubated for 72 h. The irrigation solution in nine experimental groups included: 6% NaOCl, 2.6% NaOCl, 0.5% NaOCl, 2% CHX, 0.2% CHX, MTAD, Tetraclean, Hypoclean and Chlor-Xtra. After culturing on Sabouraud 4% dextrose agar, colony-forming units (CFU) were counted. Results: 6% NaOCl, 2% CHX and Chlor-Xtra were equally effective (P>0.05) and significantly superior to MTAD and Tetraclean (P<0.05). In addition, the effectiveness of Tetraclean and MTAD was significantly less than Hypoclean, NaOCl at all concentrations (6% 2.6% and 0.5%), MTAD and 0.2% CHX (P<0.05). Furthermore, Tetraclean was significantly more effective than MTAD (P<0.05). Conclusion: Antifungal activity of 6% NaOCl, Chlor-Xtra and 2% CHX was significantly greater than 2.6% NaOCl, 0.5% NaOCl, MTAD, 0.2% CHX and Tetraclean

Severe traumatic injuries to immature teeth often cause damage to periodontal ligament as well as dental pulp; pulp necrosis, root resorption and subsequent apical lesion are common consequences. This article reports the surgical management of an infected immature maxillary central incisor associated with a gigantic periradicular lesion and severe root resorption. The tooth had a history of trauma and the patient suffered from purulent sinus tract and tooth mobility. After unsuccessful multi-session disinfection with calcium hydroxide, root end surgery was planned. During flap surgery and lesion enucleation, the root end was cleaned and filled with calcium-enriched mixture (CEM) cement. After one year, the radiographic examination revealed that the lesion was almost completely replaced with newly formed bone. In addition, clinical examination showed favorable outcomes; the tooth was symptom-free and in function. Due to chemical, physical and biological properties of CEM cement, this biomaterial might be considered as the root-end filling material of choice.