[ in vitro evaluation of the accuracy of two electronic apex locators Foramatron V and Ipex in determining working length]

Accurate determination of working length in root canal therapy is very important for success of the process. Different methods such as electronic apex locators have been introduced for determination of working length. The aim of this in vitro study was comparison of the accuracy of two electronic apex locators, Foramatron V and Ipex, in determination of working length in human single root teeth. In this in vitro study, 100 human single root, single canal maxillary incisors with developed apex without curve were used. The teeth were cleaned after extraction and stored in normal salin. After preparing access cavity, the actual length of each canal was determined by an anatomic method placing a k-file into the canal so that the file tip touched the apical foramen. After preparing the experimental environment, the teeth were placed in the model at the level of CEJ and the length of the teeth were determind with Ipex and Formatron V according to their code. The acceptable limitation was +/- 0.5 millimeter to the actual working length. After collection of data, Mac Nemar and Paired t-test were used for statistical analysis. According to the results of this study, the accuracy of length determination was 64% and 63% for Foramatron V and ipex, respectively in the range of canal length +/- 0.5 mm. There was no significant statistical difference between these two devices. There was no significant difference between Ipex and Foramatron V. Therefore, Foramatron V may be used for working length determination

[ maxillary second molar with two palatal roots: Case report]

The knowledge about the anatomic variation pulp cavity, specially in multi-rooted teeth, is an important factor for diagnosis and successful endodontic treatment. Root canal treatment of 4-rooted maxillary second molars has been described in only a limited number of case reports. The purpose of this case report was to illustrate and describe the endodontic treatment of a 4-rooted maxillary second molar. A 20-year-old female with no history of systemic disease was referred for treatment of her upper left second molar tooth. The diagnostic radiographies revealed root anomalies. After access cavity preparation, presence of four orifices in the pulp chamber was confirmed; each of them related to a distinct root. Root canal therapy was performed completely in all four roots. This case report indicates that the clinicians must be aware of anatomic variations during the diagnostic and treatment phases of maxillary molars, and proper root canal treatment should be performed respecting the presence of challenges in pulp space anatomy

Radiographic and clinical evaluation of repair of furcal mechanical perforations in premolar teeth of dog using dark MTA, white MTA and Portland cement

One of the problems affecting the prognosis of the treatment is perforation which requires immediate and proper intervention. Dark MTA is applied as material of choice to repair perforations. The purpose of this study was to evaluate the repair of mechanical furcal perforations radiographically and clinically using white MTA and Portland cement and comparing them with dark MTA. In this experimental study, second to fourth mandibular and maxillary premolar teeth of five dogs received endodontic treatment following radiographic and clinical examinations. Then, the furcation area of the teeth was perforated and repaired with dark MTA in group 1, white MTA in group 2, Portland cement in group 3 and cotton pellet in group 4 [control]. Animals were controlled for 4 months and sacrificed using an overdose of Sodium thiopental intravenous injection after radiographic and clinical examinations. Chi-square test was used to compare groups for gingival attachment and presence of radiolucency. To compare these items between each two groups, Fisher's exact test was used. There was no statistically significant difference between dark MTA, white MTA and Portland cement groups in presence of radiolucency and gingival attachment. However, all the three groups were significantly different in radiolucency and gingival attachment from control group. Both white MTA and Portland cement revealed favourable results in repair of perforations and can be used as an alternative to dark MTA to repair perforations in the areas where esthetics is important and not important, respectively

Clinical evaluation of various medication methods on the incidence of post-treatment endodontic pain in necrotic teeth

The pain after root canal treatment is one of the main problems for patient and dentist. Various drugs were studied for alleviating the pain after treatment. The purpose of this study was evaluation of various medication methods on the incidence of posttreatment endodontic pain in necrotic teeth. In this controlled double blind clinical trial, 120 patients with single canal teeth and necrotic pulps were selected. The patients were divided into six groups and randomly received drugs in one of the following ways: Group A, 2gr Amoxicillin one hour before treatment. Group B, 2gr Amoxicillin plus 4mg Betamethasone one hour before treatment. In group C, 2gr placebo [control group] one hour before treatment. Group D, 500 mg Amoxicillin immediately after treatment and continued every 8 hours for 4 days. Group E, the same treatment as group D was performed expect that, 4mg Betamethasone was added to Amoxicillin. Group F, the same treatment as group D was performed, but placebo were used instead of Amoxicillin. Root canal therapy was accomplished with step back technique and lateral condensation method. Evaluation of incidence of pain was recorded 6, 12, 24, 48 and 72 hours after treatment. Data were analyzed by Kruskall-wallis and Mann-whitney tests. The results of this study in various intervals showed that there was no significant difference in the incidence of posttreatment endodontic pain between those patients who received Amoxicillin or Betamethasone [A, B, D, E, F] and those who used placebo [control group C, F]. Most of patients that had severe pain received placebo [C and F groups]. Oral administration of corticosteroids plus antibiotic in cases with necrotic pulp did not significantly reduce posttreatment endodontic pain

[Effect of obturation techniques on obturation quality of molar C-shaped canals]

Due to the anatomic complextieis of C-shaped canals, using an obturation technique capable of filling the irregular isthmus in the root canal system seems to be necessary. The aim of this study was to compare the efficacy of three different root canal obturation techniques used for filling the irregular root canal system in C-shaped teeth. The study was perfomed on 30 human extracted molar teeth which were radiographically and anatomically recognized as having C-shaped canals. All root canals were prepared in the same way and the samples were divided into 3 groups, each of 10 teeth. The root canals in group I were filled by cold lateral condensation technique [CL]. Teeth in group II were filled by means of warm lateral condensation technique [WL] and those in group III were filled by means of warm vertical condensation technique [WV]. All teeth were demineralized and then cleared with methylsalicilate. Images were taken from both longitudinal and cross-sectional feature of the cleared teeth by a digital camera connected to a stereomicroscope. The filling quality of the main canals and the isthmus between them was evaluated by three independent endodontists. The data were statistically analyzed by chisquare, one way and two way ANOVA and t-test. In longitudinal photographs, the highest percentage of good filling quality [80%] was observed in the WV group and was significantly more acceptable than WL group [p<0.05]. The lowest percentage of good filling quality was observed in the isthmus area of the canals [46.7%] which was significantly less than other areas [p<0.05]. Cross- sectional photographs demonstrated no significant difference between the percentage of isthmuses filled with the filling material and the two areas of the canals in the three obturation techniques [p>0.05]. The results indicated that none of the suggested techniques could successfully fill the root canal space, but the warm vertical and cold lateral condensation techniques were more acceptable than warm lateral condensation technique

[Comparison of air driven handpiece and electromotor on distortion or fracture rate of nickel titanium rotary instruments]

One of the affecting factors in adverse prognosis of root canal therapy is procedural accidents as broken files, facing with difficulty in removing. Many manufacturers have designed and marketed various electromotors with the ability of controlling rotational speed and torque. On the other hand, these expensive motors have encouraged other manufacturers to marketing different air driven handpieces. Despite of presenting various vast instruments for this purpose, only limited comparative studies have been carried out between electromotor and air driven handpiece. The purpose of this study was to evaluate the effect of air driven handpiece versus electromotor on distortion or fracture rate of NiTi rotary files. This in vitro randomized controlled trial was carried out on 160 canals of human's matured molars with mild curvature [15-33°]. After initial preparation of samples and considering the inclusion criteria, in the first group, preparation was carried out with air driven handpiece and in groups 2 Endo IT [VDW, Germany] was used as electromotor. In both groups M two files with crown down technique were used for canal preparations. Data on file distortion or fracture were collected and analyzed using Mann Whitney, Mantel Cox, Kaplanmeiere and T tests. No significant differences on distortion or fracture rate of files between the two groups were found [p>0.05]. Based on survival analysis safety probability of files after preparation of 9 canals was%64.1 in group 1 and%69.9 in group 2. There was no significant differences between this safety probability in the two groups [P=0.272]. These findings showed that both electromotor and air driven handpiece has nearly similar effect on fracture rate or distortion of NiTi rotatory instruments

[ incidence of change in canal centring of the root canal following canal preparation with hand and rotary reciprocal techniques by stainless steel and nickel titanium files]

Cleaning and shaping of the root canal system is an important objective of root canal therapy. Many automatic devices have been produced to simplify the preparation, and to decrease instrumentation time. One of these automatic devices with the general name of Endogripper is the new reciprocal handpiece called TEP-E10R. The purpose of this study was to compare hand and rotary reciprocal techniques in incidence of change in canal centring of the root canal. In this invitro study, 60 extracted mesial roots [120 canals] of human mandibular first and second molars were selected. The mesial roots were mounted in a metallic muffle. Sixty specimens were divided into four groups, [each group consisted of 30 canals]. Each root was sectioned in two horizontal directions, the first cut was made five mm from the apical and the latter cut was made in the middle area of the root. The sections were photographed before instrumentation and then were reassembled in the metallic muffle and instrumented. In group one the preparations were made by NiTi files with hand instrumentation. In group two the preparations were made by stainless steel files with hand instrumentation, while in group three the preparations were made by Ni Ti files with use of TEP-E10R reciprocal handpiece, and in group four the preparations were made by stainless steel files and use of the same handpiece as in group three. After instrumentation, the metallic muffle was disassembled and the sections were photographed for the second time after preparation. The pre and post instrumentation photographs were superimposed using Adobe Photoshop and the canal center displacement in each section was measured. The collected data were analyzed with ANOVA and Tukey statistical tests. All specimens in the four groups showed canal center displacement. Group two had the most mean of canal center displacement in coronal sections which was significantly different from group one [p=0.008]. In the middle sections, the highest mean of canal center 2 displacement was seen in group four and it was significantly different from group one [p=0.001]. In the apical sections, group two had the highest mean of canal center displacement which was significantly different from other three groups [p<0.001]. Canal preparation with reciprocal handpiece [TEP-E10R] was similar to hand preparation technique with Ni Ti files in shaping of the root canal system

influence of instrument application frequency on apical extrusion of debris in three instrumentation techniques

Various kinds of hand-held or rotary techniques are used for mechanical preparation of the canal. The purpose of this study was to assess the influence of the number of applications on apical extrusion of debris in conventional and two rotary instrumentation techniques [Profile, Flex Master]. In this in vitro study, 75 extracted single-rooted human mandibular premolars with curvature between 0-10 degrees were selected and divided into three groups of 25 teeth each. All teeth were shortened to length of 15 mm by cutting the crown. Group H was prepared by hand step back technique, group P was prepared by profile system and group F was prepared by Flex Master system. The number of applications was according to manufacturer recommendation. For collection of debris, vials of distilled water were used that were weighed before preparation by 0.0001 weighing machine. At the end of canal preparation, vials were completely dried and weighed again. The difference between the weights of vials in two stages was the weight of debris extruded from apical foramen. The mean weight of debris in various numbers of applications within each system was compared by one-way variance analysis. Comparing the various numbers of applications in each system, it was noted that only in profile group, with increasing the number of applications, the quantity of debris extrusion was reduced. Unused profile instruments induce more extrusion of debris from apical foramen, rather than used ones

[Evaluation of apical microleakage in cavity preparation with different dimension for retrograde filling]

Several materials are recommended for retrofilling. One of the best materials that have ever been suggested is MTA [Mineral Tioxide Aggregate]. Many studies have confirmed the biocompatibility, proper marginal adaptation and sealability of this agent. The purpose of this study was the evaluation of apical evaluation of apical microleakge in cavity preparation with different dimension for retrograde. In this study, we examined the influence of cavity dimension on sealability of MTA. We selected sixty roots with a single canal. After cleaning and shaping, the canals were obturated with guta-percha and canal sealer by lateral condensation technique. Samples were divided into 5 groups: two positive and negative control groups and three experimental groups. Cavity preparation was performed for all experimental groups with the following methods: A: 1.5mm depth and 0.6mm width B: 3mm depth and 0.6mm width C: 3mm depth and 1.5mm width After cavity preparation, MTA powder was placed in each cavity and wet cotton adjacent to them for 24 hours. Then the samples were placed in Incubator [37 degree C and 100% wet] for 72 hours. Subsequently dye penetration examination was performed; dye leakage was measured by stereomicroscope. We used T-test for statistical analysis. After statistical analysis these results were achived: 1. Increase depth from 1.5mm to 3mm reduce the amount of leakage. 2. No significant difference between leakage of cavities with different width was found [P-value>0.05]. It's better to prepare cavities for retrograde filling with more depth and less width

[Comparison of root canal transportation during canal preparation with hand instrumentation and reciprocal automatic device]

Cleaning and shaping of the root canal system is an important objective of root canal therapy. Many automatic devices have been produced to simplify the preparation and to decrease instrumentation time. One of these automatic devices is the new reciprocal handpiece [TEP-E10R] known as general name "Endogripper". The purpose of this study was to compare canal transportation with hand instrumentation technique and reciprocal instrumentation technique with TEP-E10R handpiece. In this invitro study 60 human mandibular first and second molars were selected and divided into four groups. Radiographs with initial file inserted to working length were taken in all specimens with constant conditions. In group one, the preparations were made by Ni-Ti files and hand instrumentation technique. In group two, the preparation were made by stainless steel files and the same technique in group one, in group three preparation were made by Ni-Ti files and TEP-E10R reciprocal handpiece and in group four, the preparation were made by stainless steel files and the same handpiece in group three. Instrumentation technique in all four groups was crown down preparation. After finishing of the instrumentation in latter four groups, additional radiographs were taken while the master apical files [MAF] were inserted in the canals with the same constant conditions recorded for intial file radiographs. The MAF radiographs were compared with initial file radiographs for canal trans portation. The amount of dentin removal was also calculated by measuring instrumented surface in the final radiographs. Data were collected by SPSS10. One way ANOVA analysis was used to compare four groups and tukey test was used to compare couple groups. All of specimens showed degrees of transportation. Group two had the most mean degree of transportation that was significantly different from group one [P=0.001]. None of the groups had statistically significant difference between amount of dentin removed from canal walls [P=0.83]. Reciprocal handpices with NiTi files had acceptable results for canal preparation

Histopathological study of periapical inflammation following preparation of the root canal with conventional and profile rotary instrumentation in teeth of cats

Various factors are involved in causing inflammation following root canal treatment. Controlling these factors may relieve the related pain. One of these factors is extrusion of debris beyond the apex. Although debris extrusion happens in all instrumentation techniques, researchers have declared that in coronal flaring technique, there is minimum debris extrusion. The purpose of this study was to evaluate and compare the inflammation of periapical area following root canal therapy, using conventional and profile rotary instrumentation in cats' teeth, from a histopathological point of view. This experimental study conducted on thirty Persian one year old cats. Three groups of samples were chosen and treated with different methods. First group were prepared by step-back instrumentation technique using stainless steel K-type files. Second group were prepared by crown down technique using Ni-Ti files. Third group were prepared using profile GT rotary system at 150-rpm speed. Animals were subjected to vital perfusion at 8, 24 and 48 hour intervals after instrumentation. The canine teeth were separated from the jaw along with some of the supporting structures. Then decalcification and laboratory processing were carried out and samples were evaluated histologically. Collected data were analyzed using Kruskal-Wallis test. The results showed that in vital teeth with no evidence of periapical pathosis, the inflammation following various instrumentation methods was not statistically different. In vital teeth, the periapical inflammation following various methods of instrumentation is not statistically different

[Endodontic treatment of maxillary second molar with two palatal roots: a case report]

One of the major factors in a successful root canal therapy is the knowledge of anatomy and root canal morphology. The presence of4-rooted maxillary second molars has been described in only a limited number of case reports. The purpose of this report was to show presence of two palatal roots in maxillary second molar in one patient. A 43-year-old female patient was referred for root canal therapy of maxillary right second molar due to invasive caries. The diagnostic radiograph revealed presence of anomaly in roots. After access cavity preparation presence of four orifices in pulp chamber was confirmed and all of the steps of root canal therapy was performed. Knowledge of the most common anatomic characteristics and their possible variations of root canal morphology is fundamental. Report of uncommon cases can motivate the dentist to consider the rarities during root canal therapy