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OBJECTIVE: The use of calcium silicate-based cements has greatly increased in the past decade. This study compared coronal discolouration caused by white mineral trioxide aggregate (MTA), TheraCal (TC), calcium enriched mixture (CEM), and Biodentine (BD) on bovine enamel-dentin block. METHODS: In this in vitro, experimental study, enamel-dentin blocks (7x7x3.5 mm) were cut out of 60 extracted sound bovine central incisors. A cavity (2.5 mm diameter and 1 mm depth) was created at the center of each block with 1 mm distance from the labial surface. The blocks were randomly divided into four experimental groups (n=12) of MTA, CEM, BD, and TC and two groups of positive (blood) and negative (empty) controls. After filling cavities with experimental materials, the surfaces of the materials were covered with composite resin. The colour parameters were measured using a spectrophotometer, before (T0) and 1 week (T1), 1 month (T2), and 6 months (T3) after the application of the materials. The data was analysed using repeated measures ANOVA and the Kruskal-Wallis test. RESULTS: At 1 week and 1 month, a significant difference in ∆E was noted in the control groups compared to the experimental groups (P<0.001). The difference among the four cements was not significant (P=0.06) at 1 week but it was significant at 1 month. TC showed greater ∆E whereas BD showed lower ∆E in the six-month period (P<0.001). Colour change was significant over time in the MTA and TC groups (P<0.05). CONCLUSION: TheraCal caused greater discolouration in the bovine tooth blocks after 6 months, which may make it inappropriate for application in the aesthetic zone.

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Introduction: Bacterial leakage plays a considerable role in endodontic related failures. The aim of this study was to compare the bacterial leakage of bioceramic (including Well Root ST and MTA Fillapex) and resin-based root canal sealers (naming AH-Plus and AdSeal). Methods and Materials: Sixty-eight maxillary central incisors were included in this experimental study. These were randomly allocated into four experimental groups, which were obturated with gutta-percha and four different sealers (n=15), and the two control groups (positive, n=4 and negative, n=4). A dual-chamber technique was carried out using fresh human saliva and traced for 90 days. The Chi-square and Long Rank tests were performed for data analysis. Results: Bacterial leakage was observed in 33.3% of the samples in Well Root ST, 40% in AH-Plus group, 53.3% in AdSeal group, and 66.6% in MTA Fillapex group. The difference between the Well Root ST and MTA Fillapex groups was significant (P=0.02). The mean leakage time between the Well Root ST (85.6 days) and MTA Fillapex groups (71.2 days) was also significant (P=0.037). Conclusion: The results of this in vitro study revealed bacterial leakage in all experimental groups. The Well Root ST and the MTA Fillapex groups showed the lowest and highest bacterial leakages, respectively. Then it seems that the Well Root ST is a good substitute for MTA Fillapex in clinical applications.

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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.

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INTRODUCTION: The aim of this study was to evaluate root canal anatomy of mandibular first molars (MFM) in a selected Iranian Population using clearing technique. METHODS AND MATERIALS: A total of 150 extracted MFMs were cleared. The root canal morphology (including the root numbers and root length) and the anatomy of the root canal system (including is the number and type of canals based on Vertucci's classification, canal curvature according to Schneider's method and the presence of isthmus) was evaluated using the buccolingual and mesiodistal parallel x-rays and stereomicroscope. The data were analyzed using the chi-square test. RESULTS: Two and three roots were present in 96.7% and 33% of the teeth, respectively (P=0.0001). All the teeth (100%) had two canals in the mesial root, while 61.3% of the samples had one distal root canal (P=0.006). The root canal configuration in the mesial canal included type IV (55.3%) and type II (41.3%) (P=0.0001). In doubled-canalled distal roots, 68.8% and 24.3% were type II and type IV, respectively (P=0.0001). Isthmii were observed in 44.6% of mesial and 27.3% of distal roots (P=0.0001). CONCLUSION: The notable prevalence of type IV configuration in both roots of mandibular first molars, presence of isthmus and root curvature, necessitates the careful negotiation and cleaning of all accessible canal spaces.

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Autogenous tooth transplantation (ATT) is a simple and reasonable choice for replacing the missing teeth when a proper donor tooth is available. This report presents a case of successful ATT of a maxillary right third molar for replacement of mandibular right second molar with a concomitant endodontic-periodontal disease. The mandibular second molar was believed to be hopeless due to a severe damage to coronal tooth structure, inappropriate root canal treatment and apical radiolucency. After extraction of mandibular second molar and maxillary third molar (the donor), the tooth was re-implanted into the extracted socket of second molar site. Root canal therapy was then performed. After 3 years, clinical and radiographic examinations revealed satisfying results, with no signs and symptoms. The patient is asymptomatic and the transplanted tooth is still functional with no signs of marginal periodontal pathosis. Radiographies showed bone regeneration in the site of previous extensive periapical lesion, normal periodontal ligament with no signs of root resorption.

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INTRODUCTION: The purpose of this prospective, randomized, double-blind, placebo-controlled study was to determine whether ketorolac buccal infiltrations (BIs) helped to improve the success of inferior alveolar nerve blocks (IANBs) in patients with acute irreversible pulpitis (AIP). METHODS: Forty adult volunteers with AIP in a mandibular molar were included in this study. Patients were instructed to evaluate their pain by using a Heft-Parker visual analog scale. They were randomly divided into 2 groups (n = 20). All patients received standard IANB injection and after that a BI of 4% articaine with 1:100,000 epinephrine. After 5 minutes, 20 patients received a BI of 30 mg/mL ketorolac, and the other received a BI of normal saline (control group). Endodontic access cavity preparation (ACP) was initiated 15 minutes after the IANB when the patient reported lip numbness and had 2 electric pulp tests with no responses. The patient's pain during caries and dentin removal, ACP, and canal length measurements (CLM) was recorded by using Heft-Parker visual analog scale. Successful anesthesia was defined as no or mild pain during any of these steps, without the need for additional injection. Data were statistically analyzed by using Mann-Whitney U and χ(2) tests. RESULTS: Successful anesthesia after an IANB plus BI of articaine was obtained in 15% of patients in the control group at the end of CLM. Adding BI of ketorolac significantly increased the success rate to 40% (P < .05). Patient's pain during ACP and CLM was significantly lower in the ketorolac group (P < .05). CONCLUSIONS: Ketorolac BI can increase the success rate of anesthesia after IANB and BI with articaine in patients with AIP.

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INTRODUCTION: There are numerous factors that can lead to tooth discoloration after endodontic treatment, such as penetration of endodontic materials into the dentinal tubules during root canal treatment. The aim of this in vitro study was to compare discoloration induced by tooth colored mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement in extracted human teeth. METHODS AND MATERIALS: Thirty two dentin-enamel cuboid blocks (7×7×2 mm) were prepared from extracted maxillary central incisors. Standardized cavities were prepared in the middle of each cube, leaving 1 mm of enamel and dentin on the labial surface. The specimens were randomly divided into two study groups (n=12) and two positive and negative control groups (n=4). In either study groups the cavities were filled with MTA or CEM cement. The positive and negative control groups were filled with blood or left empty, respectively. The cavities were sealed with composite resin and stored in normal saline. Color measurement was carried out by spectrophotometry at different time intervals including before (T0), and 1 week (T1), 1 month (T2) and 6 months (T3) after placement of materials. Repeated-measures ANOVA was used to compare the discoloration between the groups; the material type was considered as the inter-subject factor. The level of significance was set at 0.05. RESULTS: No significant differences were detected between the groups in all time intervals (P>0.05). CONCLUSION: Tooth discoloration was similarly detectable with both of the two experimental materials.

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OBJECTIVE: The aim of this study was to evaluate the minimum residual root thickness (MRRT) of the danger zone after preflaring of the mesio-buccal (MB) canal of mandibular first molars using ProTaper, RaCe and Gates-Glidden (GG) drills as coronal shapers by cone beam computerized tomography (CBCT). MATERIALS AND METHODS: In this experimental study, the initial CBCT scans of 75 MB canals of mandibular first molars were provided within 1, 2, 3 and 4 mm of the furcation level. The samples were divided into three groups. The samples of ProTaper and RaCe groups were prepared up to F2 and #25.04 as the master apical file (MAF), respectively. The coronal preparation of the samples in the GG group was done using GG drills #2, #3 and #4 and canals were prepared till MAF # 25. After obtaining the postinstrumentation images, the MRRT and the amount of removed dentin were analyzed by t-test and ANOVA statistical analyses. RESULTS: The GG drills removed significantly more dentin than RaCe at all the sections (P < 0.05) and more than ProTaper at 3 mm from the furcation. Statistically there was no significant difference between ProTaper and RaCe groups (P > 0.05). There was no significant difference in MRRT between the groups (P > 0.05). The mean MRRT was not < 0.75 mm at all sections. CONCLUSION: Based on the results of this study, when an appropriate root thickness is initially present, all of the instruments that were investigated may safely be used as coronal shapers in MB canals of mandibular first molars.

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BACKGROUND AND AIM: The aim of this in vitro study was to compare Er, Cr: YSGG laser with ultrasonic preparation on the seal of retrograde cavities. MATERIALS AND METHODS: Twenty-eight maxillary anterior teeth were used in this study. After removing the crowns, the canals were prepared with the step-back technique and filled with guttapercha. Three millimeters below the apex; each root was cut with a fissure diamond bur. The root surfaces were then covered with nail polish and three millimeters deep retrograde class I cavities were prepared, using Er, Cr: YSGG laser (group L=12 roots) or ultrasonic retro-tip (group U=12 roots). Four roots were arranged for negative and positive control groups. Retrograde cavities were then filled with mineral trioxide aggregate (MTA) and teeth were placed in 2% methylene blue dye for 72 hours. The amount of dye penetration in sagittal sections of each tooth was measured with a stereomicroscope. An independent sample t-test was used for statistical analysis. RESULTS: Cavities prepared with the Er, Cr: YSGG laser (1.61 + 0.81) showed significantly less micro-leakage than those prepared with the ultrasound (2.55+ 1.84) (P value =0.02). CONCLUSIONS: Under the conditions of this research, the use of Er, Cr: YSGG laser for retrograde cavity preparation causes significantly less apical leakage and may increase the success rate of endodontic surgeries.

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Background and aims. Early diagnosis of external root resorption is important for accurate treatment. The purpose of this study was to compare the efficacy of a charge-coupled device (CCD) sensor and a photostimulable phosphor (PSP) plate receptor in the diagnosis of artificial external root resorption. Materials and methods. In this diagnostic in-vitro study, 40 maxillary incisors were mounted in a segment of dry bone and preliminary radiographs were obtained using CCD and PSP sensors. Artificial resorption cavities were produced on the middle-third in half of the samples and on the cervical-third in the other half on the buccal root surfaces. Radiographs were repeated and images were evaluated. Data were statistically analyzed using chi-square and diagnostic tests. Results. There were no significant differences between the two sensors in the sensitivity (p=0.08 and 0.06) and specificity (p=0.13) for the diagnosis of resorption in both root areas. The overall accuracy of CCD was higher than PSP sensor; however, the difference was not statistically significance (p>0.05). Conclusion. CCD and PSP sensors chosen for the present study produced similar results in diagnosing simulated external root resorption.

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INTRODUCTION: Removal of root filling materials is one of the key steps in success of root canal retreatment. The purpose of this study was to evaluate the efficacy of H-File and ProTaper with or without chloroform in the removal of gutta-percha during retreatment of mandibular premolars. MATERIALS AND METHODS: Sixty mandibular premolars with one canal, and curvatures less than 30 degrees were used in this experimental study. They were instrumented with K-files and laterally obturated with condensed gutta-percha using AH26 as the sealer and were stored in 100% humidity at 37°C for 2 weeks. The teeth were randomly divided into four groups of 15 teeth each. Removal of gutta-percha was performed with H-File and ProTaper. All techniques were used with or without chloroform. The teeth were split longitudinally and the area of remaining gutta-percha/sealer on the root canal wall was explored under stereomicroscope. Retreatment time duration was also recorded for each sample. Data were analyzed statistically by Two-way ANOVA, t-test and Tukey's. RESULTS: In all groups, no significant difference was found in remaining gutta-percha and sealer with or without using chloroform, but chloroform shortened the time of retreatment. ProTaper left significantly less remaining filling materials than H-File (P<0.05). Retreatment time was significantly different between the studied groups (P<0.001). CONCLUSION: ProTaper Ni-Ti instruments proved to be more efficient and time-saving devices for removal of gutta-percha compared to H-File in canals with no or slight curvature.

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INTRODUCTION: Mineral trioxide aggregate (MTA) has been suggested as an effective material for apical barrier, forming an effective seal against bacterial leakage in teeth with open apices. MTA needs moisture for setting; which can come from the apical region or a moist cotton pellet. This study was intended to compare bacterial leakage in one- and two-step MTA apical barrier technique in open apices with different diameters. MATERIALS AND METHODS: The root canals of 52 extracted human maxillary incisors were prepared and open apices in two different diameters of 1 and 1.4 mm were created. The samples put in experimental groups randomly. A 4-mm thickness of MTA was placed as apical barrier for both one- and two-step methods. In one-step groups (1.4 mm diameter; n=12 and 1 mm diameter; n=12), the samples were obturated immediately after placing MTA plug. For two-step groups (1.4 mm diameter; n=12 and 1 mm diameter; n=12), a moist cotton pellet was placed over the MTA plug for 3 days before root canal obturation. Four samples served as positive/negative control groups. After one week, microleakage was evaluated using bacterial penetration technique and results were statistically analyzed utilizing SPSS software and Chi-square test. RESULTS: In one-step technique 13 and in two-step technique 12 samples showed bacterial leakage. There was no statistically significant differences between two techniques (Chi square, P=1). The difference between the results related to 1 and 1.4 mm apical foramens was also not significant (P=1). Also 12 and 13 samples showed bacterial contamination in teeth with 1 mm and 1.4 mm apical foramens, respectively (P=1). CONCLUSION: It seems that leakage of MTA apical plug using one- and two-step technique is comparable; however, in vivo investigations are highly recommended for more accurate results.

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The purpose of this study was to compare the effects of ultrasonication with ethylenediaminetetraacetic acid (EDTA) and a mixture of tetracycline isomer, an acid, and a detergent (MTAD) as final canal irrigants on the smear layer, debris and erosion scores. Fifty-eight extracted single-rooted human teeth were instrumented with ProTaper rotary files up to size F3. According to the final irrigation regimen, the samples were distributed into the following groups: EDTA, MTAD, EDTA ultrasonicated for 1 min, and MTAD ultrasonicated for 1 min. The smear layer, debris and erosion scores were recorded at the apical, middle, and coronal third of each canal using a scanning electron microscope. Data were subjected to statistical evaluation using the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). There were no significant differences in smear layer or debris removal between the experimental groups. EDTA caused significantly more erosion at the middle level than MTAD. Also EDTA resulted in more erosion at the coronal level than MTAD when subjected to ultrasonication. Ultrasonic activation of EDTA significantly increased its erosive effects at the middle and coronal levels. Based on the present findings, MTAD appears to cause less dentinal erosion while allowing proper removal of the smear layer and debris.

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INTRODUCTION: The aim of this in vitro study was to compare the efficacy of two retreatment rotary systems in removal of gutta-percha (GP) and sealer from the root canal walls with and without use of solvent. MATERIALS AND METHODS: Sixty single-canalled distal roots of mandibular molars were prepared and root filled with gutta-percha and AH26. Each canal was randomly allocated to receive one of the retreatment techniques, Mtwo R or ProTaper. The groups were further divided into two subgroups: with or without the use of solvent. The cleanliness of canal walls was determined by stereomicroscope and scanning electron microscopy. RESULTS: The results showed that Mtwo R without the use of solvent was more efficient in material removal compared to ProTaper D (P<0.05). Most remnants were found in the apical third of the canals (P<0.05). CONCLUSION: Mtwo R seems to be an efficient rotary system for endodontic retreatment of root canal with GP.

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UNLABELLED:   INTRODUCTION: Blood contamination of the canal during preparation can be a major problem in endodontics; this may result in apical microleakage. The aim of this in vitro study was to evaluate the effect of blood on apical microleakage of a resin-based root canal sealer (AH26) and a polymer-based root canal sealer (Epiphany). MATERIALS AND METHODS: In this experimental study, 50 decoronated central incisors and canine teeth were prepared by RaCe rotary system and randomly divided into 4 groups (n=10). Groups A1 and A2 were obturated by Epiphany/Resilon and AH26/Gutta-percha, respectively. The obturations were performed with a single cone technique after drying root canals. In B1 and B2 groups, the test groups, 0.02cc citrated human blood was injected into dried root canals and they were obturated in the same manner. Ten specimens were served as positive and negative controls (n=5).The apical leakage was measured by means of a computerized fluid filtration method after 1 day and 3 weeks. The data was analyzed by One-Sample Kolmogorov-Smirnov, Independent Sample t-test and univariate analysis. Statistical significances were preset at α=0.05. RESULTS: There was no significant difference in apical microleakage of the two sealers after 1 day and 3 weeks in dry and blood environment (P>0.05). Sealer and environment had no interaction (P>0.05). CONCLUSION: Blood contamination has no significant effect on the apical microleakage of Epiphny and AH26.

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The purpose of this in vitro study was to compare the sealing ability of the lateral condensation technique and the BeeFill system after canal preparation by the Mtwo rotary system. Forty extracted single-rooted teeth were prepared by using the Mtwo rotary system. The teeth were then divided into 2 experimental groups (n = 15 each) and 2 control groups (n = 5 each). The specimens in groups 1 and 2 were obturated using the lateral condensation technique and the BeeFill system, respectively. The teeth in the negative control group were also obturated with the lateral condensation technique, and the specimens in the positive control group were not root-filled. The specimens were then immersed in an aqueous solution of 2% China ink for 1 week, after which the roots were cleared and the linear extent of dye penetration was measured with a stereomicroscope by 2 endodontists. The data collected were then analyzed by using the 1-sample Kolmogorov-Smirnov test and independent t test, with a significance level of P < or = 0.05. Although the mean (+/- standard deviation) dye leakage in the BeeFill thermoplasticized injection group was less than that in the lateral condensation group (1.497 +/- 0.7 vs. 2.521 +/- 1.733), there was no significant difference between the experimental groups on the parametric independent t-test (P = 0.209).

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OBJECTIVE: To compare the canal-centring ability of M two , ProFile and RaCe rotary files, in simulated curved canals. MATERIALS AND METHODS: About 30 simulated canals were prepared by M two , ProFile and RaCe rotary files. Pre and post-operative pictures were super-imposed and transportations recorded. Measurements were carried out at five different points: Canal orifice (O); half-way to the orifice in the straight section (HO); the beginning of the curve (BC); the apex of the curve (AC); the end point (EP). Intra- and inter-group comparisons were carried out by Wilcoxon;s signed ranks test and Kruskal-Wallis test respectively, using SPSS 14.0 software. RESULTS: ProFile did not change canal centricity in any point. RaCe kept centricity at HO, BC, AC and EP. M two changed canal centricity in points BC, AC and EP. M two group kept the centricity significantly less than the other two groups at BC (P = 0.004), AC (P = 0.015) and EP (P = 0.01). There was no significant difference between these three rotary files at HO. However, the difference between RaCe, M two and ProFile was significant at O (P = 0.015). CONCLUSION: ProFile and RaCe rotary files remained better centred than M two rotary files.

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The maxillary first premolar may present large number of anatomic variations. The clinician should be aware of the configuration of the pulp system. Maxillary first premolars usually have two canals. The incidence of three canals in these teeth is quite rare. This case report presents the diagnosis and clinical management of a maxillary first premolar with two distinct canals in the apical third of buccal root (type IV), drawing particular attention to tactile examination of all the canal walls.

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INTRODUCTION: We aimed to compare apical canal transportation of extracted teeth and two types of simulated resin blocks. MATERIALS AND METHODS: Mesiobuccal root of extracted maxillary molars, high hardness simulated resin blocks (Knoop hardness=40) and low hardness simulated resin blocks (Knoop hardness=22) were prepared with K-files using step-back technique (n=15 canals in each group). Double exposure radiographic technique was used for extracted teeth. Simulated resin blocks were stabilized and scanned before and after preparation. Pre and post-preparation pictures were superimposed and apical transportation was measured. The data were analyzed statistically using ANOVA and Tukey HSD tests. RESULTS: There was no significant difference in apical canal transportation between extracted teeth and high hardness resin blocks (P>0.05). Low hardness resin blocks showed more apical transportation than the other groups (P<0.05). CONCLUSION: Under the conditions of this study, apical canal transportation for extracted teeth and high hardness simulated resin blocks were similar.

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Avulsion is a serious injury which causes damage to dental and supportive tissues, ranging from 1-16 % among dental injuries and it mostly occurs in maxillary incisors. This report presents a case of replantation of a traumatically avulsed central incisor. The left central incisor of an 8 year-old boy with open apex was avulsed and was left in unclean and dry conditions. Tooth was replaced after 270 min and splinted. After 24 hours, tooth was treated endodontically. The calcium hydroxide paste was applied as intracanal medicament. After one year the calcium hydroxide was not replaced and was maintained in the canal, permanently. The tooth followed for 5 years. During follow up, the tooth kept stable. However, the resulted dent alveolar ankylosis prevented growth of the alveolar process. Spite of the fact that in children, replacement resorption leads to the loss of ankylosed teeth within 1-5 years; this tooth has remained in a stable, infra-position for 5 year and in functional position after coronal restoration. However, in such cases other treatments such as decoronation should be considered.