فهرست مطالب mohsen aminsobhani

This study compared the antimicrobial effect of electrophoresis with calcium hydroxide and electrophoresis with cupral paste in the apical area blocked by the separated instrument.

A total of 72 single-rooted human teeth were involved in the study, each decoronated to a length of 15 mm. Following the determination of the working length and root canal preparation, the teeth were autoclaved and subsequently infected with Enterococcus faecalis. Intentional fracture of a rotary instrument occurred 3mm above the apical terminus of the canal. The samples were then randomly assigned to six groups: Groups G1 and G2 received Cupral paste (Hu-manchemie GmbH, Germany) and calcium hydroxide paste (Humanchemie GmbH, Germany), respectively, with the application of electric current. In G3, sterile normal saline was used with electrophoresis. For G4 and G5, Cu-pral and calcium hydroxide pastes were applied to the root canal without electrical current, respectively. G6 was used as the positive control. Following all in-terventions, the 3mm apical segment of the specimens was removed, and the antimicrobial effect was assessed by counting colony-forming units (CFUs) in this ca-nal area.

Cupral paste, Cupral paste with electrophoresis, and calcium hydroxide with electrophoresis demonstrated a significant reduction in bacteria beyond the separated instrument (p<0.05). However, calcium hydroxide and electrophoresis alone did not exhibit statistically significant antimicrobial activity (p> 0.05). There was no statisti-cal difference observed between Cupral paste activated by electrophoresis and calcium hydroxide activated by electrophoresis (p> 0.05).

Electrophoresis enhanced medicament penetration and antimicrobial ef-ficiency in the canal blocked by the separated instrument. Cupral paste activated by electrophoresis demonstrated superior performance in all interventions.

The aim of this study was to examine the cyclic fatigue resistances #16 ProGlider, #15.02 Scout RaCe, #15.03 NeoNiti, One G and Path-File NiTi glide path files in S-shaped artificial canals.

Twenty files from each group were tested. An artificial groove simulating double (S-shaped) curved canal measuring 1.5 mm in width at the top level decreasing towards the apical reaching 0.3 mm at the tip having a 0.06 taper, 18 mm in length, and 1.5 in depth machined in a stainless steel block was used in this study. Resistance to cyclic fatigue was determined by counting the numbers of cycles to failure (NCF). Furthermore, the fragment length of the fractured tips and angle and radius of curvature formed by each file in each trajectory were evaluated. The data were analyzed using the one-way analysis of variance and Tukey’s HSD test and the level of significance was set at 5%.

NeoNiti GPS and Scout RaCe glide path files showed significantly higher NCF values compared to other evaluated glide path files (P<0.001) but no significant difference when compared with each other (P=0.67).

Based on this in vitro study NeoNiti GPS and Scout RaCe glide path files had the highest cyclic fatigue resistance in simulated double (S-shaped) curved artificial canals among the evaluated path finding files. Therefore, it seems that they can be used with more confidence in endodontic treatment of S-shaped canals clinically.

Large radicular lesions should be treated initially by orthograde root canal therapy. When the signs and symptoms of the infection (e.g. persistent purulent drainage) do not resolve after this treatment, then surgical approaches should be considered. In the cases of large radicular cysts, total enucleation of the cyst can endanger adjacent structures and teeth. Therefore, decompression or marsupialization techniques are recommended in order to decrease the size of the lesion. In this case report, a 55-year-old woman with previously initiated therapy was referred to endodontic department for management of a sinus tract associated with tooth #7. Root canal treatment was performed and intracanal irrigant (5.25% sodium hypochlorite) activated using passive ultrasonic application, various intracanal medicament (calcium hydroxide, double antibiotic paste) was used in multiple sessions, but intracanal purulent drainage was not resolved. After this, decompression was performed using needle cap to maintain the opening of the cyst and remained for three months. During this period the cavity was kept clean and rinsed by the patient with 0.2% chlorhexidine mouthwash. After three-year follow-up, radiographic examination revealed substantial osseous repair of the defect and clinical signs and symptoms were absent.

Extraoral sinus tracts of odontogenic origin often develop as the result of misdiagnosis of persistent dental infections due to trauma, caries, or periodontal disease. Due to these lesions' imitation from cutaneous lesions, misdiagnosis, and mismanagement, which we frequently encounter, this article aims to describe four cases with manifestations in different parts of the face and the neck. Patients were referred to an endodontist with a history of several surgical procedures and/or antibiotic therapy due to misdiagnosis. After comprehensive examinations, root canal treatment was performed. The resolution of signs and symptoms during the follow-up period confirmed the correct diagnosis. Dermatologists and other physicians should be aware of the possibility of the relationship of extraoral sinus tracts with dental infections. Precise examination and taking a comprehensive history can aid to prevent unnecessary and incorrect therapeutic and/or pharmaceutical interventions. Elimination of dental infection leads to complete recovery in such patients.

Cervicofacial subcutaneous emphysema (CFSE) is a rare complication. CFSE may happen following some dental procedures including root canal therapy and is caused by unintentional entry of air into potential spaces of head and neck. In the current report, a case of extensive bilateral subcutaneous emphysema -following the root perforation of a maxillary anterior tooth- is presented. A 26-year-old woman was referred for further consultation concerning her right maxillary lateral incisor; for which a poor prognosis was considered following an endodontic treatment. There was a history of sudden facial swelling during root canal therapy. With the exacerbation of the problem and experiencing other symptoms, she was hospitalised. CT scan showed bilateral extension and penetration of air into submandibular, peri-orbital and parapharyngeal spaces. Clinical and radiographic evaluations of the maxillary lateral incisor revealed mid-root perforation on its buccal side, which was sealed by MTA. Eventually, the tooth was successfully restored.

Transmission of infection by the hands of dentists and staff of dentistry centers is a major source of pathogens for patients that may cause clinical infections and can be prevented by proper hygiene. Considering the prevalence of dentistry services in the country, the present paper aims at determining the predictors of hand hygiene among the dentistry centers staff based on the health belief model.

128 dentistry staff in Tehran with more than 40 dentistry units were selected in a cross-sectional study through multi-stage probability sampling. Data were collected by an author-made questionnaire the validity and reliability of which were measured. The questionnaire included demographic variables, awareness variables, health belief model and behavioral constructs. Data were analyzed using SPSS v.16 using descriptive statistics, Pearson correlation coefficient and multiple regression test.

The obtained scores were in the medium range for the awareness and behavior and good for health belief model. Multiple regression test showed that awareness and health belief model constructs predicted a total of 27.7% of compliance with hand hygiene rules. Among the studied constructs, the perceived barrier construct (P <0.001, β = 0.432) and knowledge variable (P = 0.008, β = 0.205) were significantly predictive of hand hygiene

Emphasis should be made on the perceived barrier variables and awareness as the most important predictors of hand hygiene in the staff of dentistry centers in planning and designing educational interventions and developing educational content based on health belief model

After treating the tooth root canal, pain is one of the problems that many patients are facing. In order to reduce pain, and regarding the advice of treating necrotic teeth during several sessions, intra-canal medicaments can be used between sessions. The purpose of this study is to compare pain relieving effect of calcium hydroxide combined with three solutions of normal saline, chlorhexidine 2% and dexamethasone. This triple blind randomized clinical trial was performed on 90 necrotic molars and premolars. The patients were classified in three medicaments' groups including mixture of calcium hydroxide and normal saline (G1), chlorhexidine 2% (G2) or dexamethasone (G3) that were placed in the canal during the first treatment session. The patients were provided with a Heft-Parker Visual Analog Scale form to record their pain in different intervals of 4, 24, 48, 72 and 96 h after cleaning and shaping the root canal. Data analysis was carried out using the Chi-Square, one-way ANOVA and Repeated Measure tests. No significant difference was observed in the mean pain of the groups after 4 h (P>0.05). However, a significant difference was found between G1 and G3 in the mean pain from day 1 to 72 h after treatment. The mean pain was less in dexamethasone (G3) group (P<0.05), but the difference was not statistically significant at 96 h after treatment (P>0.05). No significant difference was found between "G2-G1" and "G2-G3" groups at different time intervals (P>0.05). The mixture of calcium hydroxide and dexamethasone compared to calcium hydroxide and normal saline in short and medium time had a significant effect on reducing pain after cleaning and shaping the root canal. It seems that the mixture of calcium hydroxide and dexamethasone can be considered as an effective medicament on reducing pain during root canal treatment sessions.

Achieving appropriate anesthesia in patients with symptomatic irreversible pulpitis in mandibular molars during endodontic treatment is always one of the most challenging aspects. Photobiomodulation (PBM) has been used in dentistry due to its anti-inflammatory properties and regenerative effects. This study evaluates the effects of PBM in the depth of anesthesia in inferior alveolar nerve block.
In this randomized clinical trial, 44 patients requiring endodontic treatment in lower molar, left or right were selected, half of them were randomly treated with PBM therapy. Laser irradiation by 980 nm diode laser with a single dose (15 J/cm2, for 20 seconds) before anesthesia was performed at the buccal aspect. Inferior alveolar nerve block was performed once. Success was defined as no or mild pain (no need for any supplemental injection), based on the visual analogue scale during access cavity preparation. Results were evaluated using SPSS software.
The results of this study showed that the necessity for supplemental injection was lower in the group receiving laser than in the group without laser (P = 0.033). The mean pain intensity during dentin cutting was lower in the group receiving laser than in the group without laser (P = 0.031). Also, the mean pain intensity during pulp dropping was lower in the group receiving laser, than the group without laser (P = 0.021).
Based on the results of this study, it seems that the application of PBM before anesthesia is effective on increasing depth of anesthesia.

The aim of this study was to compare several metallurgic properties of Neoniti instrument with four other commonly used endodontic rotary files.
Methods and Materials: Neoniti A1 (25/0.08), RaCe (25/0.06), Mtwo (25/0.06), Twisted file (25/0.06) and ProTaper Next X2 (25/0.06) were examined by differential scanning calorimetry (DSC) before and after heat treatment at 500°C. X-ray diffraction (XRD) was also performed on the specimens. Furthermore, scanning electron microscopy (SEM) and x-ray energy-dispersive spectrometric (EDS) analyses were carried out on randomly selected fractured files.
In SEM tests, dimpled ruptures, characteristic of ductile fracture, were seen in all evaluated cross sections of all files. The SEM results of all evaluated files were alike. EDS results revealed higher proportions of Nickel (Ni) rich intermetallic compounds in Neoniti; whereas, in all the other files the proportion of Titanium (Ti) rich precipitates was higher. DSC results indicated that the temperature present in the oral environment, the austenite phase existed in all files. Mtwo and RaCe files did not show austenite transformation in the temperature range evaluated in this study. Only Neoniti revealed rhombohedal phase (R-phase) transformation. After heat treatment. No significant difference was seen in the transformation temperatures of all evaluated files. XRD evaluations revealed that Neoniti contained both Ni-rich and Ti-rich precipitates. The amount of the martensite phase was higher in ProTaper Next.
The metallurgic properties of Neoniti files were different from other evaluated rotary files. This file contained higher proportions of Ni-rich precipitates.

Knowledge about the morphology of the root canal system is a pre-requisite for achieving a successful outcome in root canal treatment. In this report, a patient with a maxillary lateral incisor which had previously undergone orthograde endodontic retreatment for two times is discussed. The tooth had been misdiagnosed with a palatal groove or a root fracture, its prognosis had been determined to be poor and extraction was advised by a practitioner. During our evaluation, an unrecognized supernumerary root and root canal were detected and the tooth was maintained successfully with orthograde endodontic retreatment. The use of cone beam computed tomography (CBCT) and magnification were of significance in the treatment process of this case.

The penetration depth of irrigating solutions in dentinal tubules is limited; consequently, bacteria can remain inside dentinal tubules after the cleaning and shaping of the root canal system. Therefore, new irrigation systems are required to increase the penetration depth of irrigating solutions in dentinal tubules.
A comparative study regarding the penetration depth of sodium hypochlorite (NaOCl) solution in dentinal tubules using four methods, (1) conventional irrigation (CI), (2) smear layer removal plus conventional irrigation (gold standard), (3) passive ultrasonic agitation (PUA) and (4) Nd:YAG laser activated irrigation (LAI), took place on 144 extracted mandibular teeth with a single root canal. After decoronation with a diamond disc and working length determination, the apical foramen was sealed with wax. The canals were prepared up to #35 Mtwo rotary file and 5.25% NaOCl was used for irrigation during preparation. To study the penetration depth of NaOCl, smear layer was eliminated in all samples. Dentinal tubules were stained with crystal violet and after longitudinal sectioning of teeth, the two halves were reassembled and root canal preparation was performed up to #40 Mtwo rotary file. Then the samples were distributed into four experimental groups. Depth of the bleached zone was evaluated by stereomicroscope (20X). Data were analyzed by Kruskal-Wallis test.
The highest and lowest average for NaOCl penetration depth in all three coronal, middle and apical sections belonged to CI smear layer removal and CI. A statistically significant difference was seen when comparing the penetration depth of CI smear layer removal group to CI and PUA groups in coronal and middle third, in which the average NaOCl penetration depth of the gold standard group was higher (P The standard protocol for smear layer removal led to more effective smear layer elimination and deeper penetration depth of irrigation solutions. PUA and LAI groups exhibited less smear layer elimination and penetration depth of irrigation solutions. Therefore, CI뉧 layer removal should still be considered as the gold standard.

The purpose of this study was to evaluate the resistance to fatigue failure of five different nickel-titanium rotary files in three different curved trajectories.
A total of 150 Neoniti A1, RaCe 25.06, Mtwo 25.06, Twisted file 25.06 and ProTaper Next X2 files with the tip size of 25 were tested (n=30 for each group). Three groove types simulating curved canals were used differing in radius, arc length and position of the arc, each measuring 1.5 mm in width, 20 mm in total length and 2.5 in depth. Resistance to cyclic fatigue was determined by counting the numbers of cycles to failure. Furthermore, the fragment length of the fractured tips and angle and radius of curvature formed by each file in each trajectory were evaluated. The data were analyzed by t-test, one way ANOVA and Tukey’s HSD test.
Neoniti showed the highest and RaCe showed the lowest number of cycles to fracture (NCF) values (P The fatigue resistance of the evaluated rotary files was lower in more coronally located curvatures. Neoniti exhibited the highest and RaCe exhibited the lowest fatigue resistance compared to other evaluated files.

Musculoskeletal disorders (MSDs) have been reported as the most importantreason for early retirement among dentists. The aim of this study was to assess the prevalence of musculoskeletal disorders and body discomfort among dentists. This cross sectional and descriptive-analytical study carried out on all dentists(150 subjects) of one of universities in Tehran province. We useda visual analog scale (in order to determine the severity of body discomfort) and also a body mapquestionnaire (in order to assess musculoskeletal disorders prevalence). Data analysis was performed using the Mann-Whitney test, t-test and Kruskal-Wallis.Statistical analysis was conducted using SPSS version 22 software. According to the results of the body map questionnaire, the highest prevalence of musculoskeletal disorders was allocated to the neck (50%), shoulder/arm (45.3%) and low back (34.5%), respectively. Also results of the visual analog scaleindicated that the highest amount of discomfortwas related to low back (70.2), neck (55.4) and shoulder/arm (54.4), respectively. According to high prevalence of musculoskeletal disorders and also, high levels of body discomfort, dentists need to take corrective actions with the priorities of educational programs.

Cleaning and shaping of the root canal system is an important step in endodontic therapy. New instruments incorporate new preparation techniques that can improve the efficacy of cleaning and shaping. The aim of this study was to compare the efficacy of Mtwo and RaCe rotary file systems in straightening the canal curvature using only one file or the conventional method. Sixty mesial roots of extracted human mandibular molars were prepared by RaCe and Mtwo nickel-titanium (NiTi) rotary files using the conventional and only one rotary file methods. The working length was 18 mm and the curvatures of the root canals were between 15-45°. By superimposing x-ray images before and after the instrumentation, deviation of the canals was assessed using Adobe Photoshop CS3 software. Preparation time was recorded. Data were analyzed using three-way ANOVA and Tukey’s post hoc test. There were no significant differences between RaCe and Mtwo or between the two root canal preparation methods in root canal deviation in buccolingual and mesiodistal radiographs (P>0.05). Changes of root canal curvature in >35° subgroups were significantly more than in other subgroups with smaller canal curvatures. Preparation time was shorter in one file only technique. According to the results, the two rotary systems and the two root canal preparation methods had equal efficacy in straightening the canals; but the preparation time was shorter in one file only group.

The aim of this study was to assess the cytotoxic effects and osteogenic activity of recombinant human bone morphogenetic protein (rhBMP2) and nano-hydroxyapatite (n-HA) adjacent to MG-63 cell line. To assess cytotoxicity, the 4,5-dimethyl thiazolyl-2,5-diphenyl tetrazolium bromide (MTT) assay was used. Alkaline phosphatase (ALP) activity and osteogenic activity were evaluated using Alizarin red and the von Kossa staining and analyzed by one-way ANOVA followed by Tukey’s post hoc test. The n-HA/CS mixture significantly promoted cell growth in comparison to pure calcium sulfate (CS). Moreover, addition of rhBMP2 to CS (P=0.02) and also mixing CS with n-HA led to further increase in extracellular calcium production and ALP activity (P=0.03). This in vitro study indicates that a scaffold material in combination with an osteoinductive material is effective for bone matrix formation.

The aim of this study was to introduce modified continuous wave compaction (MCWC) technique and compare its obturation quality with that of lateral compaction (LC), warm vertical compaction (WVC) and continuous wave compaction techniques (CWC). The obturation time was also compared among the four techniques. Sixty-four single-rooted teeth with 0-5° root canal curve and 64 artificially created root canals with 15° curves in acrylic blocks were evaluated. The teeth and acrylic specimens were each divided into four subgroups of 16 for testing the obturation quality of four techniques namely LC, WVC, CWC and MCWC. Canals were prepared using the Mtwo rotary system and filled with respect to their group allocation. Obturation time was recorded. On digital radiographs, the ratio of area of voids to the total area of filled canals was calculated using the Image J software. Adaptation of the filling materials to the canal walls was assessed at three cross-sections under a stereomicroscope (X30). Data were statistically analyzed using ANOVA, Tukey’s post hoc HSD test, the Kruskal Wallis test and t-test. No significant difference existed in adaptation of filling materials to canal walls among the four subgroups in teeth samples (P ≥ 0.139); but, in artificially created canals in acrylic blocks, the frequency of areas not adapted to the canal walls was significantly higher in LC technique compared to MCWC (P ≤ 0.02). The void areas were significantly more in the LC technique than in other techniques in teeth (P < 0.001). The longest obturation time belonged to WVC technique followed by LC, CW and MCWC techniques (P<0.05). The difference between the artificially created canals in blocks and teeth regarding the obturation time was not significant (P = 0.41). Within the limitations of this in vitro study, MCWC technique resulted in better adaptation of gutta-percha to canal walls than LC at all cross-sections with fewer voids and faster obturation time compared to other techniques.

The purpose of this in vitro study was to compare the antibacterial activity of Calcium Enriched Mixture (CEM) with ProRoot Mineral Trioxide Aggregate (MTA) against Enterococcus faecalis (E. faecalis) in the presence/absence of dentin powder. Two series of freshly mixed (10, 50, and 100 mg), set crushed powder (10, 50, and 100 mg), and pieces of uncrushed set (50, 100 mg) of CEM and MTA were prepared (n=32 groups). All samples were suspended in normal saline for direct exposure test against E. faecalis; in the second series, 50 mg of the dentin powder was also added to the solution. Dentin powder suspension and bacterial suspension served as negative and positive control groups, respectively (n=2). The suspensions were incubated at room temperature for 1, 60, and 240 min; each group was tested five times and survival of the bacteria in test solutions was assessed by 10-fold serial dilutions and cultured on Brain Heart Infusion (BHI) plates. The plates were incubated at 37ºC. The mean values of log10 CFU were calculated and compared in all tested groups. The total number of tests added up to 510 times. In presence of dentin powder, freshly mixed powder from set materials, and pieces of uncrushed set materials of both tested cements killed >95% of the bacterial cell in 1 min. Adding dentin powder caused an increase in antibacterial activity of freshly mixed powder from crushed set CEM and MTA but no acceleration in bacterial killing was observed, when dentin was mixed with set or uncrushed cements. Dentin powder alone reduced the number of viable bacteria in the 4-hour duration. There were no significant differences between different weights of freshly mixed, crushed set powder and uncrushed set of CEM cement and MTA at different times. Under the conditions of this in vitro study, CEM cement as well as MTA have antibacterial effects against E. faecalis. The addition of equal amounts of dentin powder to the suspension of CEM or MTA resulted in swifter elimination of bacteria.

To evaluate differences in the root and canal configurations of mandibular permanent anterior incisors and canines in an Iranian population by means of Cone Beam CT (CBCT) images.

Four hundred CBCT images of mandibular permanent incisors and canines that met the inclusion criteria were evaluated. The number of roots, number of root canals, root length, root curvature and canal type were evaluated. For the evaluation of the samples, Vertucci´s classification was taken as the main reference.

Totally 632 central incisors, 614 lateral incisors and 608 canines were evaluated. The average length of the mandibular central, lateral incisors and canines was 21.3±0.10, 21.9± 0.13 and 25.1± 0.11 mm, respectively. All of the mandibular central and lateral incisors had one root, but the incidence of single-rooted mandibular canines and two-rooted mandibular canines was 96.3% and 4.7%, respectively. The majority of mandibular central, lateral incisors and canines had one canal (72.7%, 70.6% and 71.8%, respectively). Five types of Vertucci canal configurations were seen in the evaluated teeth. Type 1 Vertucci configuration was the most prevalent configuration (72.3%, 70.6% and 71.8% for the central, lateral incisors and canines, respectively), and type 5 Vertucci canal configuration was the least prevalent type seen (3.3%, 3.2% and 2.3% for the central, lateral incisors and canines, respectively). The most frequent root curvatures in these teeth were distally and buccally. No significant difference was seen between male and female patients regarding any of the parameters evaluated in this study (p>0.05).

More attention should be given to the detection of additional canals and the recognition of canal curvature in Iranian patients.

Chemo mechanical debridement is an important part of endodontic treatment. Elimination of pulpal tissue, microbiota and their by-products, organic and inorganic debris removal by using instruments and intracanal irrigants are objectives of this important phase of treatment. The aim of this study was to ex-vivo evaluation of smear layer removal in conventional clinical methods, Passive Ultrasonic Irrigation, Laser Activated Irrigation. 54 anterior mandibular teeth was used in this study. After preparation of samples, they were divided in to 3 groups of Conventional Irrigation +Smear layer removal, Passive Ultrasonic Irrigation, Laser Activated Irrigation. Then, the samples were cut longitudinally in mesiodistal direction for examination by SEM (1500X) for assessing smear layer removal. In coronal, middle and apical one third, the best result was obtained from Conventional Irrigation + Smear layer removal group for smear layer removal. According to better smear layer removal in Conventional Irrigation + Smear layer, it is considered as gold standard protocol and other groups cannot be a suitable substitution for this method.

The purpose of this study was to determine the effects of citrus aurantifolia (CA) extract on smear layer removal in different parts of root canals. Thirty-nine single-rooted human teeth were randomly divided into three experimental (n=12) and one control (n=3) groups. Teeth were instrumented using MTwo rotary instruments. Root canals were irrigated with NaOCl during instrumentation. The canals in each group were irrigated with one of the following: completed mixture of citrus aurantifolia extracts, 17% EDTA, and alcoholic extract of CA. Distilled water was used for the control group. The irrigants were left within the canal for 20 minutes, and then rinsed with normal saline solution. Teeth were subsequently split longitudinally into 2 halves, and the canals were examined by a scanning electron-microscope. Cleanliness was evaluated using a five point scoring system. Statistical significant difference was found between groups (P<0.05). The smear layer was more effectively removed with 17% EDTA compared to alcoholic CA extract. However, they were both able to remove the smear layer in the coronal segment. Completed CA extract removed more smear layer in coronal and middle parts compared with the alcoholic extract (P=0.001); however, there was no significant difference in the apical part. Both of the alcoholic and completed mixtures of citrus aurantifolia extracts were not able to effectively remove smear layer compared with 17% EDTA during root canal therapy.

Successful root canal treatment requires adequate knowledge regarding morphologic variations in root canal system of teeth. This report describes a six-canalled mandibular first molar with four mesial root canals requiring endodontic retreatment. The two additional canals in the mesial root were found during retreatment with the aid of illumination and magnification. In conclusion, the possibility of atypical morphology and additional canals should never be overlooked.

Root canal obturation seals the root canal system to prevent re-entry and/or growth of microorganisms. The provision of an appropriate restoration to coronally seal the access cavity affects the success of endodontic treatment. The purpose of this study was to evaluate the coronal microbial leakage in root canals that were either filled by lateral compaction, GuttaFlow or warm vertical compaction. In this ex vivo study, 80 single-rooted human extracted teeth were randomly divided into three experimental groups (n=20) and two positive and negative control groups (n=10). The teeth in experimental groups were obturated with cold lateral compaction, GuttaFlow system or warm vertical compaction techniques. After sterilization of the whole system with gamma-ray, saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank and Kaplan-Meier survival analysis tests. There were no significant differences in impeding saliva leakage between the three experimental groups (P>0.05). Under the conditions of this ex vivo study, it can be concluded that the sealing ability of cold lateral compaction, warm vertical compaction and GuttaFlow system was comparable.

Adequate cleaning, shaping and filling of the root canal system are mandatory for successful root canal treatment. Thorough knowledge of root canal morphology and unusual anatomy of the tooth is critical for the practitioner. The occurrence and location of the third mesial canal (Middle Mesial Canal) in mandibular first and second molars in relation to other two mesial canals that were treated in private practice were studied. In 27 clinical cases, the presence of a middle mesial canal was demonstrated. The third canal was located in the middle of the distance between the mesiobuccal and mesiolingual canals. This canal configuration was found in six second lower molars and twenty one first molars. Middle mesial canal in all of our cases joined to mesiobuccal or mesiolingual canals. None of the teeth consisted of three independent canals with three apical foramina. In conclusion, every attempt should be made to find and treat all root canals of a tooth.