Iranian Endodontic Journal
Year:2018 | Volume:13 | Issue:1|Papers Count:25

As the root canal system shows different and complicated anatomies, mechanical instrumentation alone has not the ability to provide a bacteria-free environment in root canals. On the other aspect, necrotic tissue remaining can decrease the effects of root canal irrigants and medicaments and also interfere with the adaptation of root canal fillings to dentin. As a result, certain disinfection and irrigation procedures are required to remove the remaining tissues from the root canal area thoroughly and also be able to eliminate the microorganisms. Triple antibiotic paste (TAP) containing metronidazole, ciprofloxacin and minocycline has been proposed as a root canal medicament due to its antimicrobial effects in endodontic regenerative procedures. The purposes of this review were to determine the properties of TAP drugs and to evaluate the efficiency of TAP on the root canal disinfection, in primary and permanent teeth, along with its affection in regeneration/revascularization procedures. The biocompatibility and disadvantages of this medicament were also discussed.

Introduction: This trial was designed to evaluate the clinical and radiographic success rates of calcium-enriched mixture (CEM) cement with and without low level laser therapy (LLLT) and compare them to that of formocresol (FC) and ferric sulfate (FS) in primary molar pulpotomies. Methods and Materials: This randomized clinical trial was conducted on a total of 160 teeth selected from 40 patients aged 3-9 years. Patients with at least four primary molars needing pulpotomy, were included in order to have each tooth assigned randomly in one of the four following groups; FC, FS, CEM, and LLLT/CEM. Six-and twelve-month follow-up periods were conducted in order to enable a clinical and radiographic evaluation of the treated teeth. Collected data were analyzed using Cochran Q Tests. Results: The 12-month clinical success rate for each technique was: FC=100%, FS=95%, CEM=97. 5% and LLLT/CEM=100% with no significant differences (P>0. 05). Furthermore, 12-month radiographic success rate for each technique was: FC=100%, FS=92. 5%, CEM=95% and LLLT/CEM=100% with no significant differences (P>0. 05). Conclusion: Favorable outcomes of four treatment techniques in pulpotomy of primary molar teeth were comparable. CEM with/without LLLT may be considered as a safe and successful pulpotomy treatment modality compared to current conventional methods.

Introduction: The aim of this study was to compare post-operative pain following one-visit pulpectomy and placing stainless steel crown (SSC), with two-visit treatment (performing pulpectomy at the first visit followed by placing SSC at the next visit one week later) in vital pulp of primary molars with carious involvement. Methods and Materials: In this randomized clinical trial, 100 children aged 6-12 years with a carious primary molar tooth in need of pulpectomy were randomly divided into two groups of 50 each. In one-visit group, pulpectomy and placement of SSC were carried out at the same appointment. In two-visit group, pulpectomy of root canals was carried out at the first visit and placement of SSC was performed at the second visit one week after the first appointment. Post-operative pain was recorded using visual analogue scale (VAS) during one week after each treatment visit. Results: No significant difference was found in the mean age and gender distribution between the two groups (P˃ 0. 05 for both comparisons). Findings revealed that in the two-visit (pulpectomy) group during first three days and 4-7 days after the first treatment appointment, pain felt by the children was significantly lower than that felt by the one-visit group at the same time period (P˂ 0. 0001 for both comparisons). Moreover, children in two-visit (pulpectomy) group consumed significantly lower amount of analgesics than those in the one-visit group (P<0. 0001). Conclusion: No significant difference was found between pain felt by children during the first three days following one-visit pulpectomy and placement of SSC at the same appointment. Therefore, one-visit treatment of vital primary tooth is recommended.

Introduction: The purpose of this study was to examine the microhardness and modulus of elasticity (MOE) of White ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK) after setting in moist or dry intracanal conditions. Methods and Materials: To simulate root canal system, 14 polyethylen molds with internal diameter of 1 mm and height of 12 mm were used. These molds were filled with 9-mm thick layers of White ProRoot Mineral Trioxide Aggregate (MTA; Dentsply Tulsa Dental, Tulsa, OK). The experimental group (n=7) had a damp cotton pellet with 1. 5 mm height and a 1. 5 mm layer of resin composite placed on it. In control group (n=7) the whole 3 mm above MTA were filled with resin composite. The specimens were kept in 37° C and relative humidity of 80% for 4 days in order to simulate physiological conditions. Specimens were longitudinally sectioned and nanoindentation tests were carried out using Berkovich indenter at loading rate of 2 mN/s at 4×5 matrices of indents which were located in the coronal, middle and apical thirds of the specimen’ s cross section, to evaluate the microhardness and modulus of elasticity of the specimen to appraise the progression of the setting process. Differences were assessed using nonparametric generalized Friedman rank sum and Wilcoxon Rank-Sum tests. Results: Statistical analysis showed that there was a significant difference in microhardness and MOE between control and experimental groups at coronal (P<0. 001), middle (P<0. 001) and apical (P<0. 001) thirds of the simulated rod from simulated apical foramen. Kruskal-Wallis test showed no significant effect of depth on microhardness of material in experimental or control groups. Conclusion: Within limitations of this in vitro study, it seems that moist intracanal environment improves setting of MTA in various depths.

Introduction: Endodontic therapy is challenging in open apex teeth. One of these problems is the residue of medicaments on root canal walls. The aim of this study was to evaluate the amount of residual materials on canal walls after the use as medicaments within natural open apex teeth. Methods and Materials: A total of 45 human extracted single-rooted premolars with open apices were selected. After cutting off the crowns, root canals were gently instrumented using #40 files and irrigated with 0. 5% sodium hypochlorite. The samples were randomly divided into three groups: calcium hydroxide (CH), triple antibiotic paste (TAP) and propolis (PP). In these groups, CH, TAP, or PP were placed into the canals, respectively. The samples were then restored with temporary fillings. After one week, instrumentation was again performed as mentioned above. The samples were longitudinally cut and scanned and the remaining material in both halves was evaluated using computer software. One-way ANOVA was used to compare the average paste level remaining on the canal walls. Results: The residual amount of CH on the canal walls was significantly higher than that of PP (P=0. 001). The residual amount of CH was higher than TAP but this difference was not significant (P=0. 144); the residual amount of TAP was higher than PP but this difference was not significant, either (P=0. 094). Conclusion: PP is superior to CH and TAP in terms of removability from the root canal system within open apex teeth.

Introduction: The root canal preparation is an important stage in the undergraduate teaching and must be handled with care. Iatrogenic mishaps may occur during this procedure which might compromise the success of endodontic treatment. The aim of this study was to determine, the frequency of iatrogenic errors in endodontic treatments provided by undergraduate dental students at the School of Dentistry of Federal University of Espí rito Santo (UFES), Brazil. Methods and Materials: Radiographic records of 511 anterior teeth and pre-molars with endodontic treatment performed by undergraduate students, between 2012 and 2014 were randomly chosen. The final sample consisted of radiographic records of 397 teeth endodontically treated and were evaluated by using the projection of radiographic images. Iatrogenic errors that were detected in root filled teeth included: apical perforation, root perforation, furcation perforation, strip perforation, presence of fractured instruments, ledge and zip. Then they were classified, according to the absence or presence of iatrogenic errors, as adequate or inadequate. Results: According to the results, 7. 3% of the teeth were inadequate, and there was no statistically significant difference among the groups of anterior teeth, incisors, or canines (P>0. 05). A ledge was present in 6. 54% of root canals, a zip in 0. 75% of root canals, and only one root canal presented a fractured instrument. In teeth with moderate curvature, the root curvature was a factor that possibly influenced the occurrence of the ledge (P<0. 05). Conclusion: The majority of root canal preparations showed a low occurrence of iatrogenic errors.

Introduction: The aim of the present in vitro study was to evaluate the genotoxicity of mineral trioxide aggregate (MTA) after adding different concentrations of disodium hydrogen phosphate and silver nanoparticles using the Ames test. Methods and Materials: TA100 strain of Salmonella typhimurium was used to evaluate mutagenicity of experimental materials with and without S9 mix fraction. The materials tested in this study consisted of MTA, MTA/disodium hydrogen phosphate and MTA/silver nanoparticles at 0. 1, 0. 01, 0. 001 and 0. 0001 concentrations. Negative and positive control groups consisted of 1% dimethyl sulfoxide and sodium azide with 2-aminoanthracene, respectively. The number of colonies per plate was determined. If the ratio of the number of histidine-revertant colonies to spontaneous revertants of the negative control colonies was *2, the material was regarded a mutagenic agent. Results: In all the concentrations of the three tested materials, the Ames test failed to detect mutations. Conclusion: Under the limitations of the present study, MTA/disodium hydrogen phosphate and MTA/silver nanoparticles were biocompatible in relation to mutagenicity.

Introduction: The objective of this animal study was to promote East Java propolis as a potential natural intracanal medicament for periapical chronic apical periodontitis bone resorption through evaluating the expression of osteoprotegrin (OPG) and osteoclast level. Methods and Materials: Propolis extract was produced using a maceration procedure. Thirty Wistar rats were divided into three groups. In group I, the control group, the first upper right molar constituted a healthy tooth. In group II, containing rodents with experimentally chronic apical periodontitis, infection with Enterococcus faecalis ATCC29212 106 CFU was performed. In group III, the treatment group, after being injected with E faecalis, 10 μ L propolis was applied. It required 21 days to induce post-pulp chronic apical periodontitis infection. The rats were euthanised for immunohistochemical examination in order to measure the expression of OPG and to count histologically the number of osteoclast. Result: The expression of OPG and osteoclast constituted 17. 5± 1. 58 and 6. 4± 0. 96 in group I, 10± 2 and 16. 2± 1. 31 in group II and 17± 1. 69 and 7. 5± 1. 08 in group III. Group I presented the highest level of OPG expression but the lowest level of osteoclast expression. There were significant differences between groups II and III and group I regarding OPG and osteoclast expression (P<0. 05). Conclusion: East Java Propolis was a potential intracanal medicament promoting an increase in osteoprotegerin expression and a decrease in the number of osteoclasts thereby inhibiting osteoclastogenesis.

Introduction: The purpose of this study was to evaluate the efficacy of cone-beam computed tomography CBCT in the diagnosis of RF in the presence of an intracanal posts with and without applying “ metal artifact reduction” (MAR) mode. Methods and Materials: This in vitro study included 60 single-canal endodontically treated premolars. Post spaces were created in all roots. RFs were simulated in 30 of the 60 teeth. Dentatus posts were cemented in 15 of 30 roots with and without RFs. Teeth were arranged randomly in 6 artificial dental arches. Images were taken using a Vatech CBCT machine with and without MAR (MAR and WMAR, respectively). A radiologist and an endodontist evaluated the CBCT images for the presence of RFs. Sensitivity, Specificity, positive and negative predictive values were determined for each mode. MC Nemar’ s and Kappa tests were used for data analysis. Results: The percentage of correct diagnosis using the WMAR mode in both the post space and pin groups in the presence of root fracture was 46. 6%; with MAR, it increased to 86. 6% and 66. 6%, respectively. There was no significant difference between two modes in post space (P=0. 503) and metal pin groups (0. 549). The overall sensitivity of VRF diagnosis in WMAR mode was 46. 67%; in MAR mode, sensitivity was 76. 67%. The specificity of WMAR and MAR modes were 60% and 53. 33%. The levels of agreement between two modes and real findings were less than 0. 45. Conclusions: There were no significant differences between the efficacies of imaging modes. The sensitivity of the MAR mode for diagnosis of VRF in both the pin and post space groups was higher than the WMAR mode. The specificity of MAR in comparison with WMAR was less or equal in dental groups. The agreement between CBCT and real findings was poor.

Eugenol-based root canal sealers (RCS) have been widely used by clinicians; however, their effect on resinous materials is still questionable. The objective of this study was to evaluate the influence of RCS at 1 week and 6 months’ post obturation on the bond strength (BS) of glass fiber posts (GFP) to root dentin, using conventional and self-adhesive cementation systems (CS). The roots of 56 extracted human canines, were divided in eight groups (n=7) according to the combination of the following factors: RCS (with or without eugenol-Endofill and Sealer 26, respectively), storage period post obturation and prior GFP cementation (1 week and 6 months) and cementation systems (Variolink II-conventional resin cement or RelyX U200-self-adhesive resin cement). After one week, the specimens were transversely sectioned into six 1-mm-thick disks and were subjected to the push out BS test. The data were subjected to 3-way ANOVA and Tukey’ s tests (
=0. 05). The BS were not affected by the RCS, neither the CS (P>0. 05). Just the period post obturation showed statistically significant differences (P≤ 0. 05), where the GFP cemented 6 months after the endodontic treatment showed higher values than those cemented 1 week after it.

Introduction: This study aimed to evaluate the cyclic fatigue resistance of two single file engine-driven instruments, Reciproc and NeoNiTi, in simulated root canals. Methods and Materials: Two groups of 15 NiTi endodontic instruments with an identical tip size of 0. 25 mm were tested: Reciproc R25 (group A) and NeoNiTi A1 (group B). Cyclic fatigue testing was performed in a stainless steel artificial canal. The simulated canals had a 60° angle and 5-mm radius curvature. The Reciproc instruments were operated using the preset program on torque control electric motor specific for the Reciproc instruments, while the NeoNiTi instruments were operated using the manufacturer recommendation. All instruments were rotated until fracture occurred, and the number of cycles to fracture (NCF) and the length of the fractured tip were recorded and registered. Means and standard deviations of NCF and fragment length were calculated for each system and data were subjected to Student’ s t test (P<0. 05). Results: A statistically significant difference (P<0. 05) was noted between Reciproc and NeoNiTi instruments. NeoNiTi A1 instruments were associated with a significantly higher mean NCF as compared to Reciproc R25 instruments (833± 176 vs. 318± 87 NCF). There was no significant difference (P>0. 05) in the mean length of the fractured fragments between the instruments. Conclusion: NeoNiTi instruments were associated with a significantly higher cyclic fatigue resistance than Reciproc instruments.

Introduction: Endodontic files which are used to clean and shape the root canal space differ from each other regarding technical specifications. Recently, K-type files are repeatedly studied on their cutting efficiency. This study aims to evaluate the tip design and cutting efficiency of 5 brands of K-files, available in Iran dental market (naming Dentsply, Thomas, Mani, Perfect and Larmrose). Methods and Materials: In this descriptive study, topographic features of file tips were investigated by the scanning electron microscope (SEM). Those features included tip symmetry, tip design, tip angle, and the distance from the tip to the lowest flute. SEM images (×250 magnification) of files were prepared. Statistical tests (Fisher's exact test, Chi-square, ANOVA, and t test) were used and P<0. 05 was considered as significant. Results: Dentsply files had the most number of morphologically pyramidal sharp tips and the greatest tip angles. However, Larmrose files were the most frequent files having cutting sharp tips. Symmetrical tips existed among 100% of Dentsply and Mani brands. No significant differences were found with respect to distance from the file tip to the lowermost flute between different file brands of this study (P=0. 2, One way ANOVA). Conclusion: Dentsply and Mani files possessed the most symmetrical tips and greatest tip angles. With respect to tip length, all 5 brands were satisfactory. However, neither of 5 brands evaluated topographically were outstanding in every aspect.

Introduction: The second canal of the mesiobuccal root (MB2) of the maxillary first molars (MFM) is difficult to detect in conventional radiographs and can be a major cause of failure in endodontic treatments. The aim of this study was to investigate the prevalence and anatomy of the MB2 by using high-resolution cone-beam computed tomography (CBCT). Methods and Materials: Three radiologists examined 414 high-resolution CBCTs. Of these, the CBCTs of 287 patients (mean age 49. 43± 16. 76) who had at least one MFM were selected, making a total of 362 teeth. Prevalence and its relation with gender and age of the patients, side of the tooth, and Vertucci’ s classification were analyzed. Data were statistically analyzed (P<0. 05). Results: A total of 68. 23% of the teeth exhibited the MB2. The presence of the MB2 was equivalent in both genders and significantly higher in younger patients. There was no correlation between the presence of the MB2 in relation to both the sides of the MFM and the FOV size. Smaller FOV recognized higher Vertucci’ s grades. Conclusions: It was concluded that the prevalence of the MB2 canal in maxillary first molars in this Brazilian population examined with high-resolution CBTCs is 68. 23%, being more prevalent in young patients. Gender and the side examined are no factors for determining the presence of MB2. Although the both FOVs of the high-resolution CBTCs (FOV 8 and 5) detect the MB2 canal, smaller FOV (FOV 5) is more accurate in the analysis of the internal anatomy of such root canals, according to the Vertucci´ s classification.

Introduction: A successful endodontic treatment depends on a comprehensive knowledge of the morphology of canal and its variations, an appropriate access cavity, proper cleaning and shaping and adequate root canal filling. The present study was carried out to evaluate the root canal morphology of permanent maxillary first molars in an Iranian population. Methods and Materials: In this in vitro study, 80 extracted permanent maxillary first molars from a population in Rafsanjan, Iran were collected. Root canal morphology was evaluated by clearing technique under stereomicroscope under 40× magnification. A combination of Vertucci’ s and Sert and Bayirli’ s classifications were used to determine the root canal types. Data were analyzed by SPSS 18 software using descriptive statistics. Results: All palatal roots and almost all distobuccal roots had type I configuration. Ten different types of root canal system were found in mesiobuccal roots, among which type I was the most common (38. 75%), followed by type II, IV, V, VI, IX, XV, XVI=XIX and VII, respectively. Conclusion: The mesiobuccal roots of permanent maxillary first molar had the most complex root configuration.

Introduction: This study was designed to determine the effect of Osteon II mineralized bone powder on the surface microhardness of two retrofilling materials: Mineral trioxide aggregate (MTA) and Biodentine (BD). Methods and Materials: Each retrograde material was mixed and carried into 30 sterile custom-made plastic cylinders. Half of the samples in each group were exposed to Osteon II. All cylinders were submerged in simulated tissue fluid and incubated at 37° C and 100% relative humidity for 7 days. Surface microhardness values of each study group was attained using Vicker’ s microhardness test. The data were analyzed statistically using two-way ANOVA and independent t test at a significance level of 0. 05. Results: In all the setting conditions, BD had significantly greater surface microhardness than MTA (P<0. 001). Surface microhardness of both materials was significantly reduced in the presence of osteon II (P=0. 006 for BD and P<0. 001 for MTA). Conclusion: Mineralized bone graft materials negatively affect surface microhardness of both MTA and BD. In presence of osteon II, BD had the highest surface microhardness.

Introduction: The aim of the present study was to evaluate the radiographic quality of RCTs performed by undergraduate clinical students of Dental School of Isfahan University of Medical Sciences. Methods and Materials: In this cross sectional study, records and periapical radiographs of 1200 root filled teeth were randomly selected from the records of patients who had received RCTs in Dental School of Isfahan University of Medical Sciences from 2013 to 2015. After excluding 416 records, the final sample consisted of 784 root-treated teeth (1674 root canals). Two variables including the length and the density of the root fillings were examined. Moreover, the presence of ledge, foramen perforation, root perforation and fractured instruments were also evaluated as procedural errors. Descriptive statistics were used for expressing the frequencies of criteria and chi square test was used for comparing tooth types, tooth locations and academic level of students (P<0. 05). Results: The frequency of root canals with acceptable filling was 54. 1%. Overfilling was found in 11% of root canals, underfilling in 8. 3% and inadequate density in 34. 6%. No significant difference was found between the frequency of acceptable root fillings in the maxilla and mandible (P=0. 072). More acceptable fillings were found in the root canals of premolars (61. 3%) than molars (51. 3%) (P=0. 001). The frequency of procedural errors was 18. 6%. Ledge was found in 12. 5% of root canals, foramen perforation in 2%, root perforation in 2. 4% and fractured instrument in 2%. Procedural errors were more frequent in the root canals of molars (22. 5%) than the anterior teeth (12. 3%) (P=0. 003) and the premolars (9. 5%) (P<0. 001). Conclusion: Technical quality of RCTs performed by clinical students was not satisfactory and incidence of procedural errors was considerable.

Introduction: This study assessed the effect of mineral trioxide aggregate (MTA) and calciumenriched mixture (CEM) cement on odontogenic differentiation and mineralization of stem cells. Methods and Materials: After confirmation of stemness and homogeneity of stem cells derived from apical papilla (SCAPs) using flow cytometry, the cells were exposed for 3 weeks to either osteogenic medium (OS) or CEM extract+OS (CEM+OS) or MTA extract in OS (MTA+OS) or DMEM based regular culture media (negative control). Relative expression of alkaline phosphatase (ALP), dentine sialophosphoprotein (DSPP), osteocalcin (OSC), and osterix (SP7) were measured at days 14 and 21 using RT-qPCR method. At the same time points Alizarin Red staining method was used to assess mineralization potential of SCAPS. Gene expression changes analysis were made automatically using REST® software and a P<0. 05 was considered significant. Results: After 2 weeks of exposure, expression of all genes were between 3 and 52 times the expression of GADPH (all were upregulated except SP7 in the control, P<0. 05). After 3 weeks, relative expressions of the genes: ALP, SP7, DSPP, and OSC were respectively 275. 9, 528. 3, 98. 4, and 603. 7 times the expression of GADPH in the control group (OS). These were respectively 17. 405, 29. 2, 11. 8, and 6. 5 in CEM+OS group, and 163. 8, 119. 7, 102. 5, and 723. 9 in MTA+OS group. All of these were confirmed as upregulated (P<0. 05) except for ALP and OSC of DM+CEM group. After 2 weeks, alizarin red staining showed similar mineralized nodules in OS, MTA+OS, and CEM+OS. In third week, larger nodules were seen in MTA+OS and OS, but not in CEM+OS. Conclusion: After 2 weeks, gene expressions were almost comparable in OS, CEM+OS, and MTA+OS. After 3 weeks, OS and MTA+OS upregulated genes much greater than in 2nd week. However, upregulation in CEM+OS might not increase in 3rd week compared to those in 2nd week.

Introduction: The aim of this study was to evaluate the ability of pressurized water irrigation technique (AquaPick Device) as an intra-canal irrigation technique and compare it with sonic irrigation device (Endoactivator) for their ability to remove smear layer from canals. Methods and Materials: Total number of 80 single rooted teeth (premolars) were prepared, divided into eight main groups, Group 1: Aquapick with apically vented needle/18 mm depth, Group 2: Aquapick with apically vented needle/15 mm depth, Group 3: Endoactivator device/18 mm depth, Group 4: Endoactivator device/15 mm depth, Group5: Aquapick with 2 side vented needle/18 mm depth, Group 6: Aquapick with 2 side vented needle/15 mm depth and two control groups. Then all samples were tested by SEM in 3, 6 and 9-mm distances from the apical foramen. The data were statistically analyzed using Kruskal Wallis and Mann-Whitney U tests. Results: There was a high significant difference among the tested groups with the best removal of smear layer by the use of pressurized water irrigation device with apical vented needle especially at the 3 mm area. Conclusion: Pressurized water irrigation technique could be used as intra-canal irrigation technique with good results.

Introduction: This in vitro study aimed at comparing the effect of agitating the final irrigant solutions of root canal by ultrasonic or using 808 nm Diode laser on the apical seal of canal. Methods and Materials: A total of 90 extracted human maxillary central incisors were prepared up to size #45 and were randomly assigned to 4 experimental groups (n=20) and two control groups (n=5) respectively, as follows: I): 3 mL of 5. 25% NaOCl was agitated as final irrigant solution with ultrasonic for 30 sec. The ultrasonic tip was 1 mm shorter than the working length, II): 3 mL of 5. 25% NaOCl was agitated as final irrigant with 808 nm Diode laser for 30 sec. Fiber tip, placed in 1 mm shorter from working length was spirally moved coronally, III): 3 mL of 17% EDTA was agitated as final irrigant with 808 nm Diode laser for 30 sec and was applied similar to group II, IV): 3 mL of 17% EDTA was stimulated as final irrigant with ultrasonic for 30 sec and was applied similar to I. Apical seal was assessed by Dual Chamber technique using Bovine Serum Albumin protein. Kruskal-Wallis and Mann Whitney tests were used with significance level lower than 0. 05% for statistical analysis. Results: The average leakage in the negative control, positive control, and groups I, II, III, IV were: 0. 00, 13. 5± 5. 1, 1. 72± 2. 9, 5. 12± 5. 6, 3. 36± 3. 7, 2. 4± 4. 2, respectively. Statistical analysis showed significant difference between groups (P<0. 05). There was a significant difference between groups 1 and 2 in terms of protein leakage. Conclusion: Agitating 5. 25% sodium hypochlorite solution as the final irrigant with ultrasonic is more effective in apical leakage reduction compared to other groups.

Introduction: The objective of this in vitro study was to evaluate whether cervical preparation with Mtwo files in a crown-down technique influences instrumentation time and the cyclic fatigue resistance of these instruments. Methods and Materials: Two instrumentation techniques were evaluated (manufacturer and crown-down). Each group consisted of 10 kits containing four Mtwo instruments (10/0. 04, 15/0. 05, 20/0. 06, and 25/0. 06), which were used to prepare three standard simulated curved resin canals. The mean instrumentation time and the corresponding number of cycles for each instrumentation (NCI) were recorded. The instruments were rotated at a constant speed of 300 rpm in a stainless-steel canal (diameter of 1. 5 mm) at a 90° angle of curvature and 5-mm radius. The center of the curvature was 5 mm from the tip of the instrument. The cyclic fatigue resistance of the files was determined by counting the number of cycles to failure (NCF). Data were analyzed by the Mann-Whitney test. Results: The mean instrumentation time and NCI of files 10/0. 04 and 15/0. 05 were significantly lower (P<0. 05) when the crowndown technique was used compared to the manufacturer’ s method for the same tip size/taper file. There was no significant difference in the mean NCF between the two techniques. Conclusion: The crown-down technique did not interfere with resistance to cyclic fatigue. However, the shorter instrumentation time of files 10/0. 04 and 15/0. 05 could reduce the fracture risk in the case of reuse of these instruments.

Introduction: The aim of this retrospective study was to analyze the frequency of C-shaped root canal configuration and characterize mandibular root canal morphology using cone-beam computed tomography (CBCT) with 3D images in an Iranian population. Methods and Materials: This study consisted of retrospective evaluation of CBCT images from 231 adult patients (153 with bilateral second mandibular molars). Two endodontists examined 384 mandibular second molars of a population in Tabriz, Iran to determine the presence of C-shaped canals and their anatomical characteristics. Root canal configurations were categorized at three different levels. Bilateral or unilateral occurrence of C-shaped canals and their relationship to gender, age and tooth position were examined and statistically analyzed using chi squared test and Fisher’ s exact test in SPSS 17. The significance level was set at 0. 05. Results: Of 384 mandibular second molars examined, 82 (21. 4%) molars from 58 patients had a C-shaped root canal configuration. The prevalence of bilateral C-shaped canals was 15. 6% amongst 153 patients with bilateral mandibular second molars. There were no significant differences in the distribution of C-shaped canals with respect to gender or age (P=0. 06 and P=0. 86, respectively). Only 4 teeth (4. 9%) had the same root canal configuration from the orifice to the apex. In the remainder of the teeth, the cross-sectional root canal configuration changed at different levels of the root. Conclusion: There were significant variations in the number of roots and canal morphology in mandibular second molars, which should be considered during debridement and obturation of the root canal system.

Introduction: The present study was set to investigate the training quality and its association with the quality of root canal therapy performed by fifth year dentistry students. Methods and Materials: A total number of 432 records of endodontic treatment performed by fifth year dentistry students were qualified to be further investigated. Radiographs were assessed by two independent endodontists. Apical transportation, apical perforation, gouging, ledge formation, and the quality of temporary restoration were error types investigated in the present study. Results: the prevalence of apical transportation, ledge formation, and apical perforation errors were significantly higher in molars in comparison with other types of teeth. The most prevalent type of error was the apical transportation, which was significantly higher in mandibular teeth. There was no significant differences among teeth in terms of other types of errors. Conclusion: The quality of training provided for dentistry students should be improved and endodontic curriculum should be modified.

This is a clinical report of a case of Oehlers type II dens invagination in left maxillary lateral incisor. A 12-year-old female patient was referred to endodontic department of Islamic Azad University. She reported history of pain and swelling on left anterior maxilla. Due to the insufficient information from conventional radiography, cone-beam computed tomography (CBCT) was ordered. CBCT revealed apical lucency and two separate canals. Conventional root canal therapy was done using warm vertical technique for invaginated canal. One year follow-up radiographies showed periapical repair and absence of symptoms.

Actinomycosis is a rare lesion of the jaws and may present as periapical pathosis; therefore, it is essential to be correctly diagnosed and managed. This case presentation describes management of a tooth with a symptomatic apical periodontitis caused by Actinomyces species supplemented with medicine prescription. A woman was referred for endodontic management of tooth #19. The tooth had a history of previous nonsurgical endodontic retreatment. Clinically, the tooth was very sensitive to percussion. Radiographic evaluation showed a large periapical lesion. Intentional replantation (IR) was planned. The tooth was atraumatically extracted. Without any curettage, through the blood flow coming out of the socket, a small yellowish granule was detected and sent for examination. After root-end preparations, the cavities were filled with calcium-enriched mixture cement and the tooth was carefully replanted. Histopathological assessment proved actinomycosis sulfur granule. According to infectious disease specialist recommendation, low-dose and long-term penicillin V was prescribed. Interestingly, at 2-month follow-up, remarkable bone healing was observed. In the cases of apical actinomycosis, IR in combination with antibiotic therapy, even without the curettage of the lesion, may be successfully employed.

Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year followup, both procedures were successful in relieving patient’ s symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development.