Publications by authors named "Shahram Azimi"

9 Publications

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effect of XP-Endo finisher on the amount of residual debris and smear layer on the root canal walls.

Dent Res J (Isfahan) 2019 May-Jun;16(3):179-184

Assistant Professor, Department of Endodontics, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.

Background: A successful endodontic treatment depends on efficient cleaning and shaping and effective irrigation of root canals. The irrigating solution may not be effective in some areas in the canal. The manufacturer of XP-Endo finisher claims that it can effectively clean the root canals with complex morphology. This study aimed to assess the effect of XP-Endo finisher on the amount of residual debris and smear layer on the root canal walls of mandibular second premolars.

Materials And Methods: In this study Fifty extracted mandibular second premolars with a root curvature <20° were collected. Root canals were prepared using BioRaCe rotary system. The root canals were in contact with the file and different irrigating solutions for 1 min. The teeth were then randomly divided into four experimental ( = 10) and one positive control group as follows: (1) XPF + saline, (2) XPF + ethylenediaminetetraacetic acid (EDTA), (3) XPF + sodium hypochlorite (NaOCl), (4) XPF + EDTA + NaOCl and (control) EDTA + NaOCl. The teeth were longitudinally sectioned into two halves and the amount of debris and smear layer remaining in the coronal, middle, and apical thirds of the roots was quantified and scored under an electron microscope. The Kruskal-Wallis test was used to compare the groups, and < 0.05 was considered statistically significant.

Results: The highest mean amount of residual debris (2.9 ± 1.13) was noted in XPF + saline group ( < 0.05). XPF + saline and XPF + NaOCl (3.8 ± 0.60) had the lowest efficacy for smear layer removal ( < 0.05) with no significant within-group difference. No significant difference was noted between Groups 2, 3, and 4 with the positive control group regarding debris removal. Groups 2 and 4 had no significant difference with the positive control group regarding smear layer removal.

Conclusion: Use of XP-Endo finisher has no superiority to the standard protocol for the use of irrigating solutions (EDTA + NaOCl) for debris and smear layer removal, but in some cases, such as second appointment of regeneration treatment we cannot use NaOCl because of its destructive effects on stem cells; thus, we can benefit from the synergistic effects of XPF and EDTA for better smear layer removal.
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May 2019

Smear layer removal evaluation of different protocol of Bio Race file and XP- endo Finisher file in corporation with EDTA 17% and NaOCl.

J Clin Exp Dent 2017 Nov 1;9(11):e1310-e1314. Epub 2017 Nov 1.

Assistant Professor, Department of Endodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.

Background: The aim of the present study was to compare the amount of the smear layer remaining in prepared root canals with different protocols of Bio RaCe files and XP-endo Finisher file (XPF) in association with 17% EDTA and sodium hypochlorite solution.

Material And Methods: A total of 68 extracted single-rooted teeth were randomly divided into 4 experimental groups (n=14) and two control groups (n=6). The root canals were prepared with Bio RaCe files (FKG Dentaire, Switzerland) using the crown-down technique based on manufacturer's instructions and irrigated according to the following irrigation techniques: Group 1: XPF with 2 mL of 2.5% NaOCl for 1 minute. Group 2:, XPF with 1 mL of 17% EDTA for one minute. Group 3: XPF was used for 1 minute in association with normal saline solution. Group 4: XP-endo Finisher file for 30 seconds in association with 2.5% NaOCl and 17% EDTA for 30 seconds. The negative control group: NaOCl (2.5%) was used during root canal preparation, followed by irrigation with 17% EDTA at the end of root canal preparation. The positive control group: Normal saline solution was used for irrigation during root canal preparation. In all the groups, during preparation of the root canals with Bio RaCe file, 20 mL of 2.5% NaOCl was used for root canal irrigation and at the end of the procedural steps 20 mL of normal saline solution was used as a final irrigant. The samples were analyzed under SEM at ×1000‒2000 magnification and evaluated using Torabinejad scoring system. Data were analyzed with non-parametric Kruskal-Wallis test and post hoc Mann-Whitney U test, using SPSS. Statistical significant was defined at <0.05.

Results: The results of the study showed the least amount of the smear layer at coronal, middle and apical thirds of the root canals in groups 2, which was not significantly different from the negative control group (<0.5).

Conclusions: Under the limitations of the present study, use of a combination of NaOCl and EDTA in association with XPF exhibited the best efficacy for the removal of the smear layer. Smear layer, XP-endo Finisher file, EDTA, Sodium hypochlorite.
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November 2017

Comparing the Efficacy of Mtwo and D-RaCe Retreatment Systems in Removing Residual Gutta-Percha and Sealer in the Root Canal.

Iran Endod J 2012 1;7(3):122-6. Epub 2012 Aug 1.

Department of Endodontics, Dental Branch, Azad University of Medical Sciences, Tehran, Iran.

Introduction: Retreatment is performed in teeth with unsuccessful root canal therapy or persistent apical lesion. The most important factor for achieving successful retreatment is thorough cleaning and reshaping. NiTi files and rotary instruments are widely used for the removal of obturatants. This study compared the ability of Mtwo and D-RaCe retreatment systems to remove residual gutta-percha and sealer within the root canal after retreatment.

Materials And Methods: This in vitro experiment was performed on sixty extracted human teeth. The samples were cut at the CEJ level, manually prepared, filled with gutta-percha and AH26 and finally stored at 37ºC for two weeks. Samples were then randomly divided into two groups. Group 1 was retreated with Mtwo and Group 2 with D-RaCe. Both groups were then divided into two subgroups retreated either with or without solvent. Teeth were then vertically sectioned for evaluation of residual filling materials on the canal walls. A microscopic assessment at 16× magnification was performed. T-test statistical analysis was used to compare the data.

Results: Comparison between the Mtwo and D-RaCe rotary systems revealed no significant differences in residual gutta-percha or sealer on canal walls (P=0.2). The study revealed a negative effect of solvent on removal of gutta-percha and sealer in both the Mtwo and D-RaCe systems.

Conclusion: Mtwo and D-RaCe retreatment files removed residual gutta-percha and sealer similarly; there was no significant difference between them.
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October 2012

Effect of Synthetic Tissue Fluid on Microleakage of Grey and White Mineral Trioxide Aggregate as Root-End Filling Materials: An in vitro study.

Sultan Qaboos Univ Med J 2012 Aug 15;12(3):323-9. Epub 2012 Jul 15.

Research Center of Pharmaceutical Nano Technology, Tabriz University (Medical Sciences), Tabriz, Iran;

Objectives: The success of endodontic surgery has been shown to depend partly on the apical seal. Grey mineral trioxide aggregate (GMTA) produces hydroxyapatite twice as often as white mineral trioxide aggregate (WMTA) when suspended in a phosphate buffered saline (PBS) solution. The aim of this in vitro study was to compare the microleakage phenomenon of gray and white mineral trioxide aggregates as root-end filling materials after immersion in synthetic tissue fluid (STF).

Methods: 55 single-rooted extracted maxillary anterior human teeth were divided into two experimental groups of 20 teeth each, plus 3 groups of 5 teeth each as two negative and one positive control groups. The root canals were cleaned, shaped, and laterally compacted with gutta-percha. The root ends were resected and 3 mm deep cavities were prepared. The root-end preparations were filled with GMTA or WMTA in the experimental groups. Leakage was determined using a dye penetration method. Data were analysed using analysis of variance (ANOVA) at the 0.05 level of significance.

Results: The mean dye leakage was 0.40 ± 0.1 mm for GMTA and 0.50±0.1 mm for WMTA groups, respectively. There was no significant difference between the two experimental groups (P = 0.14).

Conclusion: Despite the different properties and behaviours of GMTA and WMTA in STF, there were no significant differences in microleakage when using GMTA or WMTA.
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August 2012

Comparative antibacterial efficacy of endemic satureja khuzistanica jamzad essential oil, sodium hypochlorite and chlorhexidine gluconate solutions as root canal irrigations.

Dent Res J (Isfahan) 2011 ;8(1):28-32

Assistant Professor, Department of Drug and Food Control, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.

Background: The aim of this study was to compare the antibacterial efficacy of endemic Satureja Khuzistanica Jamzad (SKJ) essential oil as root canal irrigation versus 2.5% sodium hypochlorite and 2% chlorhexidine gluconate.

Methods: In current in vitro experimental study, fifty four single-rooted teeth were randomly divided into 6 groups of 9 samples: 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate (CHX), 0.31 mg/ml SKJ, 0.62 mg/ml SKJ, positive and negative controls. Each tooth was instrumented, sealed and autoclaved. Then, test groups were inoculated with E. faecalis, treated with irrigation solution and viable bacterial counts in intracanal dentin chips were determined. Utilizing SPSS 18 software, collected data were analyzed by Kruskal-Wallis one way analysis of variance (P = 0.05).

Results: 99.94 % and 99.50% reduction in bacteria load after 5 min treatment with NaOCl and CHX were detected, respectively. Similarly, 99.97% and 99.96% reduction in bacterial counts were observed after 5 min application of 0.62 mg/ml and 0.31 mg/ml SKJ essential. No significant differences were detected among the four irrigation solutions (P = 0.755).

Conclusion: SKJ essential oil with the minimum inhibitory concentration (MIC) of 0.31 mg/ml could be an effective antibacterial irrigation solution.
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October 2012

Cyclic Fatigue Resistance and Fractographic Analysis of Race and Protaper Rotary NiTi Instruments.

Iran Endod J 2011 15;6(2):80-6. Epub 2011 May 15.

Department of Endodontics, Dental School, Islamic Azad University of Medical sciences, Tehran, Iran.

Introduction: This study investigated the fatigue and fracture modes of RaCe and ProTaper rotary instruments.

Materials And Methods: Fatigue resistance was evaluated by rotating the files 30° or 60° and with 2 or 5mm radius of curvature. RaCe taper 06 size 25 and ProTaper F1 files (n=40) were used. The number of rotations to failure was analyzed by two-way ANOVA and independent sample t-test. Fracture surfaces were examined under a scanning electron microscope.

Results: Both files exhibited significantly more resistance to fracture when angle severity was reduced and increase in curvature radius (P=0.000). ProTaper demonstrated higher number of cycle of failure (P=0.0029) in one group (r=5mm, 60º). SEM observation revealed fatigue mark/features in 17 specimens, shear characteristics in 37 samples, and tensile overload in 26 samples.

Conclusion: Radius of curvature was the main factor in torsional and fatigue failures.
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November 2012

Antibacterial activity of endemic Satureja Khuzistanica Jamzad essential oil against oral pathogens.

Iran Endod J 2009 7;4(1):5-9. Epub 2009 Jan 7.

General Dentist, Tehran, Iran.

Introduction: To assess the antibacterial effects of an Iranian endemic essential oil, Satureja Khuzistanica Jamzad (SKJ) when used as an intracanal antiseptic and interappointment medicament.

Materials And Methods: Antimicrobial activity and minimum inhibition concentrations (MICs) of SKJ essential oil with and without calcium hydroxide (CH) against eleven aerobic, microaerophilic and anaerobic bacteria were assessed. The evaluation was carried out by agar dilution and well diffusion methods. The results were measured and recorded by an independent observer. Data were analyzed statistically using student t-test.

Results: The MIC for eight species was recorded in 0.31 mg/mL of essential oil. Pseudomonas aeruginosa with a MIC value of 1.25 mg/mL appeared to be the most resistant bacterium; while only 0.16 mg/mL of essential oil was sufficient to inhibit the growth of Bacillus subtilis and Staphylococcus aureus. The inhibition zone of the antiseptic oil (at 0.31 mg/mL) with E. faecalis in the well diffusion method was 13 mm; this was comparable with 12.5 mm inhibition zone value of the tetracycline disc (30 µg). No synergistic effect was found in combination of essential oil and CH powder.

Conclusion: SKJ essential oil with the concentration of 0.31 mg/mL is effective against most of oral pathogens including E. faecalis.
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July 2013

SEM Study of Root Canal Walls Cleanliness after Ni-Ti Rotary and Hand Instrumentation.

Iran Endod J 2007 1;2(1):5-10. Epub 2007 Apr 1.

Department of Endodontics, Dental school, Islamic Azad University of Medical Sciences, Tehran, Iran.

Introduction: To compare the cleaning effectiveness of K3 and Race NiTi rotary systems with K-Flexo file instruments during the preparation of curved canals in extracted human teeth.

Materials And Methods: A total of 50 root canals of mandibular and maxillary molars with curvatures ranging between 25º and 35 º were divided in three groups of 15 each and 5 as negative control groups. Canals were prepared using a low torque control motor in two rotary groups according to manufacturer's instructions. Conventional Step back with S.S K files was the preparation technique in third group. The amount of debris and smear layer was quantified on the basis of a numerical evaluation scale. The data were statistically analyzed using Chi-Square and Likelihood Ratio tests.

Results: In general, no significant difference in terms of amount of debris were found among three groups, only in apical zones of Race and K-Flexo file groups a significant difference was detected (P=0.041). Race rotary system left significantly less smear layer than k-Flexo file in the middle (P=0.009) and apical thirds (P=0.012), respectively. K3 significantly achieved higher scores of cleanliness than K-Flexo file in apical third only (P=0.049). No significant difference between Race and K3 rotary groups for residual debris and formed smear layer was detected.

Conclusion: Obtaining higher scores of cleanliness in various regions of the canals, crown down technique and the use of rotary instrumentation seem to be superior to conventional hand instrumentation with step back technique .No significant difference between K3 with three radial lands and Race with three cutting edges in terms of debris and smear layer formation was detected.
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December 2013

Component analysis of four commercial brands of gutta-percha.

Iran Endod J 2006 ;1(2):49-52

Polymer Eng., Engineering Research Institute, Tehran, Iran.

Introduction: Gutta-Percha, the concrete milky juice of the Sapotaceae family tree, is the most commonly used material for obturation of prepared canal space. Natural 1-4 trans stereochemical structure of Gutta-Percha is taken to a heating- inclusion process of various organic and inorganic elements by manufacturers. The purpose of this study is to detect the presence and percentage of inorganic filler elements and organic phase of various commercial brands and if the locally manufactured brand confonns to standard range of components.

Materials And Methods: Sample cones, size # 35, from Roeko, Hygienic, DiaDent and AriaDent brands were randomly selected. After burning out in the furnace, organic and inorganic phase percentage and presence of trace elements in each sample were detected and recorded using apparatuses such as SEM, XRF, TGA, IR, NMR, and Ion Chromatography.

Results: With slight differences in polymer / filler ratio, 78% ± 2% for organic phase, no significant difference was recorded among these brands. SEM analysis detected Zinc, Barium, and Sulfur in Hygienic, DiaDent, and AriaDent in descending order; in the last two Silicones was also traced, while Zinc was the only element to be identified in Roeko.

Conclusion: No significant chemical and structural differences among four commercial brands were detected.
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January 2014