Step-back Technique Research Articles

Apical Sealing Ability of Mineral Trioxide Aggregate, Intermediate Restorative Material and Calcium Enriched Mixture Cement: A Bacterial Leakage Study.

Introduction:This in vitro study compared the apical sealing ability of three common root end filling materials namely mineral trioxide aggregate (MTA), intermediate restorative material (IRM) and calcium-enriched mixture (CEM) cement using a bacterial leakage model.Methods and Materials:The study was conducted on 83 single-rooted human teeth. Tooth crowns were cut and root canals were prepared using the step-back technique. Apical 3 mm of the roots were cut and a three-mm-deep cavity was prepared using an ultrasonic instrument. The samples were divided into three groups (n=25) according to the root-end filling material including MTA, IRM and CEM cement. The roots were inserted into cut-end microtubes. After sterilization with ethylene oxide, microtubes were placed in sterile vials containing 10 mL of Brain Heart Infusion (BHI) broth and incubated at 37°C and 0.1 mL of Enterococcus faecalis suspension compatible with 0.5 McFarland standard (1.5×108 cell/ ml), which was refreshed daily. This procedure was continued for 70 days. The data were analyzed using the chi-square, Kruskal-Wallis and log rank tests. The level of significance was set at 0.05. Results:No significant difference was found in bacterial microleakage among three groups; MTA showed slightly (but not significantly) less microleakage than IRM and CEM. However, the difference in the mean time of microleakage was significant among the groups (P<0.04) and in MTA samples leakage occurred in a longer time than CEM (P<0.012). Conclusion:The three tested root end filling materials had equal sealing efficacy for preventing bacterial leakage.

The effect of irrigating solutions on the apical sealing ability of MTA Fillapex and Adseal root canal sealers

Background. Maximum sealing ability or adhesion of endodontic sealers can be achieved after effective removal of the smear layer. Endodontic irrigants assist in adequate removal of the smear layer, improving the retention mechanism. The aim of this study was to evaluate the effect of two different root canal irrigation solutions (5.25% NaOCl followed by 17% EDTA and QMix) on the apical sealing ability of two different root canal sealers (MTA Fillapex and Adseal).Methods. Forty-six single-canal teeth were divided into 4 experimental groups of 10 teeth each and a positive and negative group of 3 teeth each. The root canals were prepared using step-back technique. The teeth in groups 1 and 2 were irrigated with 5.25% NaOCl followed by 17% EDTA and the teeth in groups 3 and 4 were irrigated with QMix. Finally all the teeth were flushed with sterile saline and dried using paper points. Obturation was accomplished by gutta-percha using lateral condensation technique. MTA Fillapex sealer was used in groups 1 and 3 whereas Adseal was used in groups 2 and 4. Dye penetration method was used to evaluate apical leakage. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests using SPSS 14. Statistical significance was set at P < 0.05.Results. Group 3 showed maximum amount of apical leakage (3.7±0.3 mm) whereas group 2 exhibited the least amount of apical leakage (2.1 ± 0.4 mm) among all the experimental groups. Significant differences were found in the amount of apical leakage between all the groups (P = 0.00001).Conclusion. Within the limitations of this study, 5.25% sodium hypochlorite followed by 17% EDTA and Adseal resulted in the best apical seal.

Effect of Different Endodontic Sealers on the Push-out Bond Strength of Fiber Posts.

Introduction:The aim of this in vitro study was to evaluate the effect of MTA-based sealer (MTA Fillapex), eugenol-based sealer (Dorifill) and an epoxy resin sealer (AH Plus) on the bond strength of fiber posts cemented with a self-etch adhesive. Materials and Methods:The root canals of 72 maxillary incisors were prepared using the step-back technique after removing/cutting off the crowns. The samples were randomly divided to 4 groups (n=18). In group 1 (the controls) gutta-percha was used without sealer. In groups 2, 3 and 4, the canals were filled with gutta-percha using AH Plus, Dorifill and MTA Fillapex sealers, respectively, by cold lateral compaction technique. After post space preparation, the fiber posts were cemented in the root canals using self-etch adhesive. Then 1-mm-thick disks were prepared from the coronal thirds of all the root canals and subjected to a push-out test. Data were analyzed using the one-way ANOVA and post hoc Tukey’s tests. Results:The maximum (4.45±0.09 MPa) and minimum (1.02±0.03 MPa) bond strength values were recorded in the control and Dorifill groups, respectively. The mean push-out bond strength values were similar for MTA Fillapex and AH Plus sealers (P>0.05). However these values were significantly higher than that of the Dorifill sealer (P<0.05). Conclusion:Sealer type affected the bond strength of the fiber posts and MTA Fillapex decreased the dislodgment resistant of the fiber post.

Comparative evaluation of efficacy of ethylenediaminetetraacetic acid, maleic acid, and dimercaptosuccinic acid against the combination of these with sodium hypochlorite for removal of smear layer: An in vitro scanning electron microscope study.

Context:The effect of dimercaptosuccinic acid (DMSA) and maleic acid (MA) when used alone on smear layer has been evaluated with mixed results, but their effect when combined with sodium hypochlorite (NaOCl) has not been studied.Aim:To compare the effectiveness of ethylenediaminetetraacetic acid, MA, and DMSA against the combination of these with NaOCl in the removal of smear layer.Settings and Design:n = 4pq/L2q = 1 − pp = Incident rateL = Allowable errorMethods:One hundred and forty extracted, anterior teeth were radiovisiographically assessed. Access preparation was done; apical patency was established. Cleaning and shaping was accomplished using step-back technique. The specimens were randomly allocated as per the final irrigation protocol. After final irrigation, teeth were prepared for scanning electron microscope analysis, and the middle and apical thirds of radicular dentin were evaluated at ×1000 for evaluation of severity of occlusion of dentinal tubules with smear layer.Statistical Analysis:The data were statistically analyzed using the Student's t-test and kappa test.Results:For combined irrigation, 10% DMSA + NaOCl was significantly better than all other groups both in the middle third and the apical third. It was more effective in the middle third than at apical third.Conclusion:Ten percent DMSA in combination with NaOCl removes the smear layer more effectively at both the middle and apical third.

A comparison of the sealing ability of various temporary restorative materials to seal the access cavity: An in vitro study.

Introduction:In multiple-appointment root canal treatment, a temporary filling material is used to seal the access cavity between visits. The primary function of this material is to prevent the contamination of the root canal system by fluids, organic debris, and bacteria from the oral cavity.Material and Methods:A total of fifty extracted noncarious unrestored human maxillaryanterior teeth with intact crowns and roots were selected The canals were instrumented using stepback technique and sodium hypochlorite (3%) and hydrogen peroxide (3%) were used as irrigants for each specimen alternatively. The coronal two-thirds of each canal were flared using Gates-Glidden drills up to no. 3 size and obturated with Gutta-percha using zinc oxide-eugenol (ZnOE) as sealer. The teeth were then randomly selected and divided into six groups out of which four were experimental groups and two control groups. The teeth were then immersed in 2% methylene blue dye solution for 3 days. All sealing materials and Gutta-percha were gently removed from the walls of the canal, and the entire circumference of the canal wall examined for dye penetration.Results:The lowest mean leakage was in the Fermit-N group followed by Cavit-W, ZnOE, intermediate restorative materials (IRM), and positive control.Conclusion:Fermit-N showed better sealing ability compared to cavit, ZnOE and IRM.

ASPECTE ALE TRATAMENTULUI BIOMECANIC DE CANAL – TEHNICA STEP-BACK. STUDIU IN VITRO

Evaluation of post-operative root canal shape have been performed using simulated root canals in resin blocks and magnification analysis (stereomicroscope) have been used for the study. The technique selected was stepback with conventional hand stainless steel instruments. The aim of studies on post-operative root canal shape is to evaluate the conicity, taper and flow and maintenance of original canal shape and to record the degree and frequency of straightening, apical transportation, ledging, zipping, teardrops, elbows. Ideal preparation forms for the root canals can be possible without any preparation errors with circular incorporation of the original canal cross section – if the technique starts with adequately precurved negotiating files. Preparation errors (zips, canal transportation, apical perforations, elbows, teardrops, etc) can occur mostly when stainless steel hand instruments (K-file) are used for moderate to severe curved of root canals, especially K-file with cutting tips and not prebent. Ideal preparation shape without any preparation errors could be a final shape and adequate shape even for conventional hand files and step-back technique. For the first area of step back technique, even for the begining, we can usually use various prebent stainless steel hand instruments for pathfinding. In many cases, conventional hand instruments produces adequate shapes for the root canals. For this final shape, is important to use adequately precurved negotiating files. Conventional stainless stell are rigid enough that thay should be precurved to match the curvature of the canal during instrumentation. Conventional hand instruments has two basic design, Kerr-file and Kerr-reamer. Kerr-file could be used to enlarge the canal with a longitudinal filing action. Kerr-reamer may used in a same fashion, but is much more flexible instrument than K-file. Noncutting tip follow the canal better than instruments with active tips – clinically usefull element.

A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques

IntroductionApical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape). MethodsForty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P < .05. ResultsAll the instrumentation techniques resulted in bacterial extrusion, with manual step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P < .05). ConclusionsThe engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion.

Effect of spreader size on microleakage of roots filled with cold lateral compaction technique.

Objectives:To evaluate the effect of spreader size on apical leakage of maxillary incisor teeth.Materials and Methods:A total of 75 permanent human teeth with no carious and no fracture or crack were used for this study. After removing the crown from the cementoenamel junction and the standardization of the root lengths, the specimens were randomly divided into five groups: Group 1 - Roots were not instrumented. Group 2 - Root canals were enlarged using the step-back technique to a #40 file and filled using cold lateral compaction (CLC) of gutta-percha (GP). Group 3 - During the filling procedure, the first spreader used was size 40. Group 4 - The first spreader used was size 35. Group 5 - The initial spreader used was size 25. The amount of leakage through the filled root canals was evaluated by computerized fluid filtration model. Statistical analyzes were done using Kruskal–Wallis test and Mann–Whitney test (P < 0.05).Results:There were statistically significant differences among the groups (P < 0.05). While the uninstrumented group (Group 1) had no leakage, instrumented but not filled roots (Group 2) demonstrated the highest leakage values. There were no differences between Group 3 and 4. Group 5 showed significantly less leakage than Group 3 and 4.Conclusion:Spreader size used during CLC of GP appeared to be a significant factor on apical leakage of roots. Using smaller size spreader during CLC may provide relatively less leakage.

Evaluation of Different Dentin Bonding Agents Accompanied with Composite Coronal Barrier

Introduction: The purpose of this study was to evaluate the sealing ability of dentin bonding agents in root canals obturated with gutta-percha and MTA. Methods: Forty-five single rooted human premolar teeth were decoronated so that remaining root portions were 12 mm in length. The samples were divided randomly into three experimental (n=13) and two control groups (n=3). All teeth were instrumented up to #40 K-file using step-back technique. The roots were obturated with gutta-percha/AH26 and MTA for 5 and 3 mm, respectively. Excite, Clearfil SE Bond, and iBond were applied for experimental groups and then 2mm was filled with composite Filtek Z250. The roots in the controls were merely instrumented and obturated. Two coats of nail varnish were applied on the surface of the teeth in the experimental and positive groups, except 2 mm around the apical foramen and coronal surfaces. In the negative control, the surfaces were completely covered by two layers of nail varnish. After thermocycling, the roots mounted in plastic caps of tubes containing BHI medium and inoculated coronally with Enterococcus faecalis. The data were statistically analyzed using Fisher's exact and Kaplan-Meier survival Analysis. Results: There were no statistically significant differences between three experimental groups regarding the leakage rate (P=0.738). Conclusion: Within the limitations of this study, it was observed that the adhesive systems in alliance with gutta-percha and MTA obturation could not entirely

Effect of various post materials and resin luting cements on microleakage in endodontically treated root canals

The effect of various post materials luted with different resin luting cements on microleakage in root canals was studied in the present study. Sixty carious and crack-free premolars were prepared using a step-back technique and obturated with gutta-percha. The roots were randomly divided into six groups (n = 10). Two different post types, glass fiber reinforced posts and zirconium posts (ZP), were cemented three different resin adhesive cements (Panavia F 2.0, Smartcem 2, and Variolink II) in the root canals. All specimens were thermal cycled and stored in the methylene blue solution for one week. The roots were sectioned horizontally into three sections: apical, middle, and coronal. The occlusal direction of each section was digitally photographed under a stereomicroscope. Dye penetration area was calculated as the methylene blue-infiltrated surface divided by total dentin area. After the two-way Anova test results, Tukey HSD and Bonferroni tests were used for multiple comparisons. According to the test results, ZP luted with Panavia F showed the best microleakage results and glass fiber posts luted with smartcem 2 showed the most unsuccessful microleakage results (p = 0.146).

An In Vitro Comparison of the Apical Seal Produced by Three Different Thermoplasticized Guttapercha Obturation Techniques in Oval Canals

AbstractThe aim of this study was to evaluate and compare the sealing ability to obturate oval canals with three thermoplasticizedguttaperchaobturation techniques taking lateral condensation technique as the control. Ninety-five freshly extracted teeth were decoronated at 2mm coronal to CEJ. Biomechanical preparation was done using step back technique. The teeth were divided into three experimental groups of 30 teeth each and one control group of 5 teeth. The group I (control group) was obturated with lateral condensation technique, group II obturated with injectable thermoplasticizedguttapercha technique, group III obturated with thermoplasticizedguttapercha with downpack and backfill technique andgroup IV obturated with core carrier thermoplasticizedguttapercha technique. The sealability of each technique was assessed by a dye penetration method. The roots were given two full layers of nail polish varnish except apical 2mm. Specimens were then immersed in India ink for 48 hours. Robertson’s technique was used to clear the specimens. The linear dye penetration was measured from anatomic apex to the deepest extent of dye penetration in a coronal direction using triocular stereomicroscope at 10 × magnification. The mean dye leakage of group I was 2.6700mm;group II 0.1713mm;group III 3.3977mm; group IV 2.3210mm. When the means of all the four groups were compared using Kruskal Wallis test the difference was found to be very highly significant with the value&lt;.001**, meaning there by that group II is significantly better than the other three groups as far as sealing ability is concerned.

Evaluation of apical leakage in root canals obturated with three different sealers in presence or absence of smear layer.

Microleakage can result in failure of endodontic treatment. An important characteristic of endodontic sealer is sealing ability. The aim of this experimental study was to compare the apical leakage of teeth obturated with gutta-percha and three different sealers (resin- and zinc oxide eugenol-based) with/without smear layer (SL). In this study, 100 single-rooted teeth were used after cutting off their crowns. Cleaning and shaping was carried out with step-back technique and the samples were randomly divided into three groups (n=30) which were then divided into two subgroups (n=15) according to the presence/absence of SL. Two negative and positive control groups (n=5) were also prepared. In the various groups, the canals were obturated with gutta-percha and either of the test sealers (AH-26, Adseal or Endofill). The samples were submerged in India ink for 72 h. Then they were longitudinally sectioned and observed under a stereomicroscope at 20× magnification. Data were analyzed with descriptive statistical methods and one-way ANOVA. The significance level was set at 0.05. The mean penetration length of dye in AH-26, Adseal and Endofill samples were 2.53, 2.76 and 3.03 mm, respectively. The differences between three groups were not significant (P>0.05); also, the mean dye penetration in AH-26, Adseal and Endofill samples in presence or absence of the SL was not significantly different. AH-26, Adseal and Endofill were similarly effective in prevention of apical microleakage. Differences in the mean dye penetration between the groups with/without the SL were not statistically significant.

Evaluation of Sealing Ability of AH Plus And TG Root Canal Sealers in the Presence and Absence of Smear Layer

Background:Smear layer is considered to be the main contributing factor in better sealing and adhesion of a sealer.Objective:The aim of this study is to determine the sealing ability of two root canal sealers (AH Plus and tg). In the presence and absence of smear layerMethodology:Extracted teeth from patients visiting Sardar Begum Dental College 60 in numbers were used in this study. Specimens were divided in to two main groups (group1 and group 2) both groups were instrumented using a step back technique. Irrigation was done during instrumentation with one ml of 5.25% NaOCl solution. In group2 a final flush with 10 ml of 17% EDTA solution followed by 10ml of 5.25% NaOCl was used for smear layer removal. Each group then further divided in to two sub groups (n=15). After obturation specimens were kept in separate containers with wet gauze to maintain 100% humidity. The specimens were coated with nail polish except for apical 2mm. Specimens were then suspended vertically in two % methylene blue dye for 7 days. Longitudinal sectioning was done to determine the extent of dye penetration using a stereo microscope at X30 magnification. Student t test was used for statistical analysis (p≤ 0.05).Results:The results showed that in the presence of smear layer, mean apical dye leakage of AH Plus was2.89 mm and tg was 4.02 mm. While in the absence of smear layer the mean dye leakage of AH Plus was 2.23 mm and tg was 3.28 mm. Student t test was more than p value indicating non significant result for both sealers.Conclusion:Apical sealing ability of AH Plus is better than tg root canal sealer in the presence and absence of smear layer.

Evaluation of the Effect of Sodium Hypochlorite Irrigant on Pull-out Bond Strength of FRC Posts Using Different Resin Cements

Introduction: To evaluate the effects of using sodium hypochlorite irrigant on pull-out bond strength of self-etch and self-adhesive resin cements to dentin. Methods: Sixty intact premolars were decoronated and the root canals were prepared by step-back technique. The teeth were divided into two groups according to the irrigant used during root canal treatment: 5.25% sodium hypochlorite and normal saline. The canals were obturated and after 48 hours storage, 8mm depth post space was prepared with application of normal saline as irrigant. Then, each group was divided into two subgroups depending on the type of the cements used for cementation of fiber reinforced composite (FRC) posts (Panavia F2or Embrace). The pull-out bond strength test was evaluated. Statistical analysis was performed by Two-way AONVA. Results: The type of cement had no statistically significant effect on the bond strength; however, the type of irrigant was statistically effective. There was no interaction between two independent variables. The application of sodium hypochlorite significantly decreased the pull-out bond strength in Embrace cement in comparison with the use of normal saline. Conclusion: The type of irrigants used in endodontic treatment may affect on bond strength of FRC posts cemented by self-adhesive cements.

FARKLI ADEZİV SİMANLAR İLE SİMANTE EDİLEN FARKLI FİBER POSTLARIN MİKROSIZINTILARININ KANTİTATİF OLARAK DEĞERLENDİRİLMESİ

Purpose: The aim of this in vitro study was to compare the microleakage of two fiber-reinforced post systems cemented with luting agents that utilize two currently available adhesive approaches in three segments of teeth. Materials and Methods: Forty two extracted human maxillary central incisor and canine teeth with straight root canals were prepared using a step-back technique and obturated with gutta-percha using lateral condensation. Following standardized post-space preparations, the roots were divided into 2 fiber-post groups (Carbopost, RelyX Fiber Post) and further divided into 3 subgroups of 7 specimens each for the adhesive approach (Panavia F, RelyX Unicem, Maxcem). All specimens were thermal cycled 2500 times between 5°C and 55°C and stored in methylene-blue solution for 24 hours. Bonded specimens were cut horizontally into three sections (Cervical, Medium, Apical) and each section was evaluated using a stereomicroscope at original magnification X12. For each image, dye penetration was estimated as the ratio of methylene-blue-infiltrated surface divided by total dentin surface. The data were statistically analyzed by using the Kruskal-Wallis test and Mann-Whithney U test (p<0.05). Results: Carbon fiber-reinforced posts demonstrated significantly higher microleakage in cervical root sections (p<0.05) than the glass fiber-reinforced posts. For the glass fiber-reinforced post groups, the least microleakage was observed for the Panavia F 2.0 in all root sections, while the highest microleakage was observed for the Maxcem (p<0.05). Regardless of the post types, Panavia F 2.0 demonstrated the highest sealing ability, while Maxcem exhibited higher microleakage in all root sections (p<0.05). Conclusion: In all root section glass fiber-reinforced posts cemented with Panavia F 2.0 had the least microleakage when assessed using a dye penetration technique

An In vitro comparative evaluation of a hand file and three rotary Nill Instruments for removing gutta percha during root canal re-treatmen

Objective: To evaluate the efficacy of NITI mechanical rotary instrumentation and Hedstrom file for gutta percha removal using dearing technique.Method: Forty extracted human single rooted premolar, each with a single canal were selected. The samples were decoronated to leave 17 mm root and Instrumented with K-flles upto MAF 30 using step back technique. Samples were obturated using cold lateral condensation of gutta-perdta and AH Plus sealer. The teeth were then randomly divided Into four groups of 10 specimens each. After 2 weeks all the canals were then retreated by either ProTaper re-treatment files, M--two re-treatment files, R-Endo re-treatment flies or Hedstrom flies. The amount of remaining filling materials after re-treatment procedures was assessed by stereomlcroscope. Also time required for reaching original working length and for removal of obturating material (in min) was measured. Statistical analysis was accomplished using one way Kruskal-Wallls ANOVA and Mann-Whitney U test.Result: M-two re-treatment flies showed least amount of gutta perdta/sealer followed by Pro Taper re-treatment files, R-Endo re-treatment flies and Hedstrom files.Conclusion: Under the experimental conditions, significant difference was observed between Pro Taper re-treatment flies&amp;... Hedstrom flies and Mtwo re-treatment flies&amp;... Hedstrom flies for gutta percha/sealer removal. Complete removal of materials did not occur with any of the instrument systems investigated.&#x0D;

Analysis of the effectiveness of calcium hydroxide removal with variation of technique and solvent vehicles.

Calcium hydroxide (Ca(OH)2) paste filling is largely used as intra-canal medication and can be combined with different vehicles. Removal of that paste should be preceded by obturation, to avoid the occurrence of apical microleakage. To evaluate the efficiency of removal of pulp Ca(OH)2, from using different vehicles (water, propylene glycol) and removal techniques (mechanical and ultrasonic). Twenty-four premolars and four human incisors were prepared with step-back technique and divided into six groups according to the removal techniques and vehicles used: Group distilled water/mechanical removal, Group distilled water/ultrasonic removal, Group propylene/mechanical removal, Group propylene/ultrasonic removal, negative control group, and positive control group. The differences between groups were analyzed. The teeth were prepared by step-back technique. The samples were evaluated by stereomicroscopy, using a scoring system for the evaluation of residues in the canal. Mann-Whitney test was used to a comparison between groups with the same vehicle. For comparison between groups, regardless of the vehicle, we used the Kruskal-Wallis test, considering P < 0.05 for both tests. Groups using distilled water or propylene glycol did not show statistically significant results. When the groups were compared, differences were detected between groups distilled water/propylene and mechanical removal/removal ultrasonic, with the first featuring superior performance. None of the removal techniques employed in this study was able to completely remove Ca(OH)2 from the root canal. However, the use of distilled water as a vehicle and ultrasonic removal presented the best performance.

Comparing the Coronal Seal of Different Thicknesses of MTA with Gutta-Percha after Post Space Preparation.

Introduction. The aim of this study was to compare the coronal seal of different thicknesses of MTA with gutta-percha after post space preparation. Materials and Methods. A total of 50 maxillary central incisors randomly divided into 5 experimental groups (n = 8). After preparation of the root canals with step back technique, in groups 1 and 2, post spaces were prepared and 4 or 5 mm gutta-percha remained in the apical, respectively. In groups 3, 4, and 5, there was 1-2 and 3 mm MTA in the apical, respectively. The ten teeth serve as control groups. The teeth were connected to a bacterial microleakage evaluation system. The study period was 120 days and the samples were evaluated on ten-day intervals; Meier-Kaplan technique was used for estimation of the mean time of microleakage to occur. Log-rank test was used for comparison of microleakage. Results. Number of samples exhibiting microleakage in MTA was less than those of gutta-percha at all intervals. Means of days with no microleakage were maximum and minimum with 3 mm MTA and 4 mm gutta-percha, respectively. Conclusion. Obturation of root canals using the MTA technique provides a proper seal with the minimum thickness of MTA in teeth requiring post space preparation.

Multidisciplinary Management of An Maxillary Right Lateral Incisor With Internal Root Resorption

The aim of the present case report was to present the treatment approach and three years outcome of the treatment of a maxillary right lateral incisor with internal root resorption. A 36-year-old male patient suffering from recurrent pain in the maxillary right lateral incisor was referred to our clinic. After clinical and radiographic examination, an internal resorption was observed in the maxillary right lateral incisor. Following access cavity preparation, the root canal was prepared with K-files using step back technique, and calcium hydroxide paste was placed in the root canal at the end of the appointment. After two weeks the patient was asymptomatic, and the root canal was obturated with gutta-percha and bioceramic-based root canal sealer using lateral compaction technique. At the 12 months follow-up examination, patient was suffering from mild pain around the related tooth and there was a sinus tract associated with the resorption area. Access to the resorption area was achieved by elevating a full thickness mucoperiostal flap and the granulation tissue was removed. Mineral trioxide aggregate was applied to the resorption area and was compacted into the defect. At the three years follow-up, the tooth was asymptomatic and significant healing of the periradicular lesion was observed radiographically.

A comparison of Er, Cr: YSGG laser with ultrasonic preparation on the seal of retrograde cavities.

The aim of this in vitro study was to compare Er, Cr: YSGG laser with ultrasonic preparation on the seal of retrograde cavities. 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. 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). 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.