In vitro evaluation of Kedo-S and RaCe rotary files compared to hand files in preparing the root canals of primary molar teeth.

BACKGROUND AND AIMS: Considering the advantages of rotary files in instrumenting the root canals of permanent teeth and a lack of adequate data on the use of these systems in primary teeth, the present study aimed to evaluate two rotary files and compare them with hand files in the cleaning efficacy of the root canals of primary molar teeth. MATERIALS AND METHODS: In the present study, three groups of teeth were prepared with Kedo-S paediatric rotary file system, RaCe (reamer with alternating cutting edges), and hand files (n = 40). The groups were evaluated under a stereomicroscope concerning the cleaning efficacy of the files after cleaning the teeth in the apical, middle, and coronal thirds. The data were analyzed with SPSS 24 (IBM Corporation, USA, 2016) using Fisher's exact test and chi-squared test; statistical significance was set at p < 0.05. RESULTS: There were no significant differences in the apical and middle thirds between the different study groups. However, there were significant differences in the coronal third between the hand file and Kedo-S (p = 0.016) and RaCe and Kedo-S (p = 0.001) groups. CONCLUSIONS: The present study showed that Kedo-S files were more effective than RaCe and hand files in the coronal area than the hand and RaCe files.

Comparison of the Efficacy of NeoNiTi, ProTaper, and Reciproc Files in the Retreatment of Curved Root Canals: a CBCT Assessment.

Objective: Effective tools and methods are applied during root canal retreatment to eliminate root canal obturation materials and preserve the initial root canal anatomy. The present study compared the efficacy of Reciproc, Neoniti, ProTaper, and Hedstrom files in the retreatment of curved root canals. Material and methods: In the present in vitro study, 100 root canals with 25‒45º curvatures were used. After the samples were initially prepared and examined by CBCT, the root canals were obturated with gutta-percha and randomly assigned to four groups (n=25). A retreatment was carried out in each group with NeoNiTi, ProTaper, Reciproc, and Hedstrom files. CBCT examinations were carried out again under the same conditions. The samples were evaluated at 3-, 6-, and 9-mm distances from the apex on the first and the second CBCT image for root canal transportation and remaining gutta-percha in the root canals. The time required for retreating each canal in each sample was recorded. One-way ANOVA and corresponding non-parametric tests were applied for data analysis. Results: The root canal transportation in the NeoNiTi group was lower than that in the other groups and significantly different from the ProTaper group (P<0.05). There was a remaining gutta-percha after retreatments in all the four groups, which was not statistically significant (P>0.05). Conclusion: Despite the fact that the NeoNiTi file produced less transportation than other file systems evaluated in the retreatment of curved root canals, all the files were very effective at the clinically acceptable levels.

Comparison of Microleakage of Mineral Trioxide Aggregate Apical Plug Applied by the Manual Technique and Indirect Use of Ultrasonic with Different Powers.

STATEMENT OF THE PROBLEM: A mineral trioxide aggregate (MTA) apical plug is commonly applied prior to endodontic treatment of open-apex teeth. However, difficult application and condensation of MTA in the apical region is a drawback of this technique. PURPOSE: This study aimed to compare the microleakage of MTA apical plug applied by the manual technique and indirect use of ultrasonic with different powers. MATERIALS AND METHOD: In this in vitro, experimental study, divergent open apices were created in 48 single-rooted, single-canal teeth using ProFile. The teeth were randomly divided into four experimental groups (n=10). All groups received 5-mm thick MTA apical plug at the apical region using one of the following methods. In group 1, MTA was manually condensed while in groups 2-4, indirect ultrasonic energy with minimum, medium, and maximum power levels was used for MTA plug condensation. After setting of MTA, the apical microleakage of the MTA plug was quantified using the fluid filtration method. Data were analyzed using the Mann-Whitney and Kruskal-Wallis tests (p< 0.05). RESULTS: Significant differences were noted in microleakage of MTA plug between the manual group and ultrasonic groups with medium (p= 0.043) and maximum (p= 0.029) power levels. No significant difference was noted in microleakage of other groups (p> 0.05). CONCLUSION: Considering the current results, it seems that application of MTA with indirect ultrasonic energy at medium or high power level would decrease the microleakage of MTA plug in open-apex root canals.

Endodontic management of a rare case of the geminated maxillary second molar tooth using CBCT.

This report illustrates a rare case of a geminated maxillary right second molar tooth using CBCT in a 23-year-old man with severe pain. Nonsurgical endodontic treatment was performed, which gave rise to an asymptomatic tooth at the 12-month follow-up.

In Vitro Transportation of Curved Canals Following Glide Path Preparation by Path File and Scout RaCe Rotary Systems versus Manual Instrumentation Using Cone-Beam Computed Tomography.

Objectives: This study aimed to assess root canal transportation of curved canals following glide path preparation by PathFile and Scout RaCe rotary systems compared with manual instrumentation with stainless steel (SS) hand files using cone-beam computed tomography (CBCT). Materials and Methods: This in-vitro experimental study was conducted on extracted human mandibular first and second molars (n=51) with 25-45° canal curvature in their mesiobuccal root. All teeth underwent CBCT and were randomly divided into three groups (n=17). In group 1, a glide path in the mesiobuccal canal was created using SS hand files to the working length. In groups 2 and 3, after canal negotiation with a #8 SS hand file, a glide path was created with PathFile and Scout RaCe systems, respectively. The teeth underwent CBCT. Pre- and postoperative CBCT scans were compared to calculate the magnitude of canal transportation at 3, 6, and 9 mm from the apex. The results were analyzed using the Kruskal-Wallis and Freedman tests (P<0.05). Results: Manual instrumentation caused significantly higher canal transportation at 3 and 9 mm from the apex compared with rotary systems (P<0.05). PathFile and Scout RaCe were not significantly different at 3 (P=0.39) or 9 mm (P=0.99). No significant difference was noted in canal transportation among the three groups at 6 mm (P=0.15). Conclusion: Scout RaCe and PathFile cause less canal transportation than manual instrumentation with SS files when used for glide path preparation in curved canals, especially in the apical third.

The Effect of Root Canal Irrigation with Combination of Sodium Hypo-chlorite and Chlorhexidine Gluconate on the Sealing Ability of Obturation Materials.

OBJECTIVES: The aim of this study was to evaluate the effect of the precipitate that was formed by combining Sodium Hypochlorite (NaOCl) and Chlorhexidine Gluconate (CHX) on the sealing ability of root canal obturation materials. MATERIALS AND METHODS: The fluid filtration method was conducted on a total of 100 roots. Samples were randomly divided into two control (n=5) and three experimental groups (n=30). The samples in group 1 were irrigated with 1.5 mL of 2.5% NaOCl, and then the smear layers of the teeth were removed by 17% EDTA, while the specimens of group 2 were irrigated by 1.5 mL of 2.5% NaOCl and 1.5 mL of 2% CHX; after the smear layer removal, a final flush with 1.5 mL of 2.5% NaOCl was performed. The samples of group 3 were irrigated the same as group 1 but after the smear layer removal canals were irrigated again with 1.5 mL of 2.5% NaOCl and then a final flush with 1.5 mL of 2% CHX was performed. Teeth were obturated with gutta-percha and AH26 sealer and after seven days, microleakage was evaluated by the fluid filtration technique. The results were analyzed by the ANOVA and Tukey's test. RESULTS: The samples in group 3 had significantly greater microleakage compared to teeth in group 1, 2 (p<0.05), and the specimens in group 1 showed significantly less amount of microleakage than samples in group 2, 3 (p<0.05). CONCLUSION: The presence of the precipitate that is formed due to interaction between NaOCl and CHX has negative effect on the sealing ability of gutta-percha and AH26 sealer.

Effect of prior calcium hydroxide intracanal placement on sealing ability of MTA plugs.

This study sought to investigate how pretreatment intracanal placement of calcium hydroxide (Ca(OH)2) affected the sealing ability of mineral trioxide aggregate (MTA) plugs in simulated open apices. Maxillary central incisor teeth were cleaned and shaped in an identical manner. After root-end resection, samples were divided randomly into 2 control (n = 5) and 2 experimental groups (n = 35). The specimens in Group 1 were pretreated using a Ca(OH)2 medicament, while the samples of Group 2 received no medicament. One week later, a 5 mm apical plug of MTA was applied into the canals. The remaining portions of the canals were obturated with gutta percha. Group 1 had a significantly higher frequency of apical leakage than Group 2 (P < 0.05).

Continued root formation after delayed replantation of an avulsed immature permanent tooth.

Introduction. Tooth avulsion in the young permanent dentition is a frequent finding, and its prognosis depends on the treatment of the avulsed tooth before replantation, the extra-alveolar time, the storage medium, and the patient's general health. The present report describes management of an immature avulsed lower central incisor 90 minutes after the accident. Methods. A right lower central incisor of a 7-year-old girl was avulsed, and it was soaked in a glass of milk. 90 minutes after avulsion, replantation was performed, and the tooth was splinted; but after two weeks the replanted tooth's pulp was necrotic. Thus, endodontic treatment was performed and root canal was filled using a calcium hydroxide and iodoform paste (Metapex). Three months later, the intracanal medication was washed out and the canal was sealed using an apical plug of calcium enriched mixture (CEM) cement. Results. 20 months after replantation the tooth was completely asymptomatic, with physiologic mobility. Also, continued root formation including an apical segment beyond the artificial apical plug was observed. Conclusion. Creation of an appropriate apical barrier following the disinfection of root canal system promoted continued root-end growth in a replanted immature permanent tooth.

Digital radiography with computerized conventional monitors compared to medical monitors in vertical root fracture diagnosis.

INTRODUCTION: Vertical root fracture (VRF) is a complication which is chiefly diagnosed radiographically. Recently, film-based radiography has been substituted with digital radiography. At the moment, there is a wide range of monitors available in the market for viewing digital images. The present study aims to compare the diagnostic accuracy, sensitivity and specificity of medical and conventional monitors in detection of vertical root fractures. MATERIAL AND METHODS: In this in vitro study 228 extracted single-rooted human teeth were endodontically treated. Vertical root fractures were induced in 114 samples. The teeth were imaged by a digital charge-coupled device radiography using parallel technique. The images were evaluated by a radiologist and an endodontist on two medical and conventional liquid-crystal display (LCD) monitors twice. Z-test was used to analyze the sensitivity, accuracy and specificity of each monitor. Significance level was set at 0.05. Inter and intra observer agreements were calculated by Cohen's kappa. RESULTS: Accuracy, specificity and sensitivity for conventional monitor were calculated as 67.5%, 72%, 62.5% respectively; and data for medical grade monitor were 67.5%, 66.5% and 68% respectively. Statistical analysis showed no significant differences in detecting VRF between the two techniques. Inter-observer agreement for conventional and medical monitor was 0.47 and 0.55 respectively (moderate). Intra-observer agreement was 0.78 for medical monitor and 0.87 for conventional one (substantial). CONCLUSION: The type of monitor does not influence diagnosis of vertical root fractures.

Comparison of endodontic biomaterials as apical barriers in simulated open apices.

Objectives. To evaluate the effect of apical foramen diameter and apical barrier thickness on the sealing ability of mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) plugs in open apices. Materials and Methods. The fluid filtration method was conducted on a total of 136 roots. Samples were randomly divided into two control (n = 8) and four experimental groups (n = 30). Apical foramen diameters measuring 1.1 and 1.7 mm were shaped for groups "1 and 3" and "2 and 4", respectively. In groups 1 and 2 MTA plug and in groups 3 and 4 CEM plug was inserted. The groups were further divided into subgroups according to the thickness of the apical plugs (3- or 5-mm). Microleakage was measured at 1, 7, and 30 days. Results. Mixed ANOVA test showed that the microleakage in groups 1 and 3 as well as all 5-mm plug subgroups were significantly less than groups 2 and 4 (P < 0.05) and 3-mm subgroups (P < 0.05), respectively. Microleakage was significantly lower at 30th day (P < 0.05). Conclusions. Reducing canal diameter or increasing apical plug thickness and the time interval increases the sealing ability of apical barriers. Furthermore, in comparison to MTA, CEM plugs demonstrated superior sealing ability.

Effect of calcium hydroxide on the apical leakage of Resilon-filled root canals: An in vitro study.

Calcium hydroxide is used as an intracanal medication for root canal disinfection and to enhance periapical lesion healing. However, calcium hydroxide remnants can negatively affect the final apical seal of obturated canals. The current study investigated apical leakage in root canals filled with Resilon after calcium hydroxide treatment. Seventy human maxillary central incisors were instrumented to a master apical file size of 40. Teeth were randomly divided into two experimental groups (A and B; n = 30) and two control groups (n = 5). Root canals in group A received a calcium hydroxide dressing, while those in group B received no intracanal medication. One week after treatment, all root canals were obturated with Resilon/Epiphany using lateral compaction. Groups A and B were randomly divided into subgroups A1, A2, B1, and B2 (n = 15). All subgroups were stored in an incubator at 37 degrees C and 100% humidity; subgroups A1 and B1 were stored for one week, while subgroups A2 and B2 were stored for eight weeks. Dye penetration and clearing techniques were used to evaluate apical leakage. Data were analyzed using a Student t-test, with significance set at P < 0.05. Observed apical leakage was significantly higher in subgroup A1 than in subgroups A2 and B1 and in subgroup A2 than in subgroup B2; no statistically significant difference was found between subgroups B1 and B2. When used as an intracanal medication, calcium hydroxide increases the apical leakage of root canals filled with Resilon/Epiphany.

Detection of vertical root fractures using digitally enhanced images: reverse-contrast and colorization.

Root fracture diagnosis is a clinical difficulty that in most cases can only be detected through radiography. The objective of this study was to compare the diagnostic accuracy of two types of digitally enhanced images (reverse-contrast and colorization) with original digital radiographies in detecting experimental root fractures. Two hundred extracted single-rooted human teeth were endodontically instrumented and then divided in two groups, one control group and one test group, including fractured teeth. Vertical root fractures were experimentally made in the fractured group. The digital image of each tooth was taken, using the paralleling technique. There were three groups of images: (i) original, (ii) reverse contrast, and (iii) colorized. Three experienced dental specialists examined the images with no prior knowledge of the distribution of the root fractures. Two-way analysis of variance was used to assess the differences in accuracy, sensitivity, and specificity of each technique in detecting root fractures. Cohen's kappa coefficients were calculated to investigate the degree of interobserver agreement. The accuracy, sensitivity, and specificity of original images were 67.4%, 66.7%, and 68%, respectively; these amounts were 61.5%, 61%, and 65.5% in reverse contrast images and 66.4%, 70.7%, and 62% in colorized digital radiography. The original images had the best inter observer kappa coefficients (between 0.45 and 0.55). The results showed that the accuracy of original images is better than reverse contrast and colorized images. Use of reverse-contrast and colorization digital images in root fracture detection should be regarded as an adjunct to other diagnostic methods not as a highly critical diagnostic aid.

Endodontic management of a maxillary first molar with two palatal canals and a single buccal canal: a case report.

Thorough knowledge of root canal morphology is essential for the endodontic therapy. There are rare variations in canal number and configuration in maxillary molars, which could affect treatment outcome. This paper presents the endodontic management of a maxillary first molar with two palatal canals in one root (Vertucci type IV) and a single buccal canal. In this paper cone-beam computed tomography was made to asses this morphology. This paper is intended to reinforce clinician's awareness of the rare morphology of root canals.