Preparation Of Root Canal System Research Articles

Evaluation of Mechanical Versus Manual Root Canal Preparation in Primary Molars-A Comparative In Vitro Study.

The endodontic treatment of primary teeth is to maintain the function of the tooth free of symptoms until its physiological exfoliation. A critical factor for success is how quickly and effectively the root canal preparation can be performed. Therefore, the aim of this comparative in vitro study was to analyze the efficiency of two mechanical root canal preparation systems FM (FlexMaster) and HF (HyFlex EDM) to manual KF (K-file) on extracted primary molars. A total of 45 teeth were divided into three groups (n = 15): KF (#15-35), FM (04#30) and HF (25/~ OneFile). Root canal preparation was performed, and the preparation time was measured. All root canals were non-destructively analyzed by micro-computed tomography in the cervical, middle and apical thirds before and after preparation with regard to the parameters of canal transport (in μm) and centering ratio (0-1). Statistical analysis was performed at a 5% significance level using non-parametric tests. HF caused the lowest canal transport in the apical third (p = 0.008). The centering ratio value of HF was significantly higher in the middle third of the root canals than in the other two groups (p < 0.01). The mean instrumentation time was significantly higher for KF (6.67 min) than for FM (4.69 min) and HF (4.03 min, p < 0.01). HF can be recommended for primary molar root canal treatment.

Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Instrumented With K3XF Rotary Files Using Different Tapers.

To compare the effect of different tapers of the K3XF file system on the fracture resistance of endodontically treated mandibular premolars obturated with a three-dimensional (3-D) obturation system. For the study, 80 freshly extracted human mandibular premolars with single well-developed roots without any curvatures were taken and the tooth roots were wrapped in a single layer of aluminum foil, and they were placed vertically in a plastic mold filled with self-curing acrylic resin. The access was opened, and working lengths were determined. The canals were instrumented keeping an apical size of #30 by different taper rotary files: Group 1: un-instrumented (control group), Group 2: 30/.04, Group 3: 30/.06, Group 4: 30/.08 K3XF file system, and teeth were obturated using a 3-D obturation system, and access cavities were filled using composite. Both experimental and control groups were subjected to fracture load using a conical steel tip (0.5mm) attached to a universal testing machine to record force applied in newton until root fracture. Root canal instrumented groups showed lower fracture resistance than the uninstrumented group. Hence it could be concluded that endodontic instrumentation with increased taper rotary instruments caused a decrease in fracture resistance of the teeth, and biomechanical preparation of root canal system with rotary or reciprocating instruments caused a significant decrease in fracture resistance of endodontically treated teeth (ETT), thereby decreasing their prognosis and long-term survival.

Impacts of different Nickel-Titanium rotary and reciprocating root canal preparation systems on the amount of apically extruded debris.

This study aimed to evaluate the amount of apically extruded debris caused by different NiTi files. One hundred mandibular premolars were included in this study. The specimens were divided into five groups (n= 20): (i) TruNatomy, (ii) WaveOne Gold, (iii) 2Shape, (iv) ProTaper Next and (v) Reciproc Blue. The extruded debris was collected into preweighed Eppendorf tubes. These tubes were weighed again, and the net weight of debris was calculated. Data were statistically analysed, and the significance level was set at 5%. The least amount of extruded debris was observed in the TruNatomy group (p< 0.05). Statistically significant differences were not found among (iii), (iv) and (v) groups (p> 0.05). However, these groups resulted in significantly higher amounts of debris when compared to (i) and (ii) groups (p< 0.05). The results lead us to conclude that all instrumentation systems caused apical extrusion of debris at varying weights.

Comparison of five rotary systems regarding design, metallurgy, mechanical performance, and canal preparation-a multimethod research.

To compare the design, metallurgy, mechanical performance, and canal preparation of 5 rotary systems. A total of 735 25-mm NiTi instruments (sizes 0.17[0.18]/.02v, 0.20/.04v, 0.20/.07v, 0.25/.08v, 0.30/.09v) from ProTaper Gold, ProTaper Universal, Premium Taper Gold, Go-Taper Flex, and U-File systems were compared regarding overall geometry and surface finishing (stereomicroscopy and scanning electron microscopy), nickel and titanium ratio (energy-dispersive spectroscopy), phase transformation temperatures (differential scanning calorimetry), mechanical performance (torsional and bending tests), and unprepared canal surface (micro-CT). One-way ANOVA and Mood's median tests were used for statistical comparisons with a significance level set at 5%. Stereomicroscopic analysis showed more spirals and high helical angles in the Premium Taper Gold system. All sets of instruments had symmetrical spirals, no radial lands, no major defects, and an almost equiatomic ratio between nickel and titanium elements, while differences were observed in their tips' geometry and surface finishing. At room temperature (20°C), DSC test revealed martensitic characteristics for ProTaper Gold and Go-Taper Flex, and mixed austenite plus R-phase for the Premium Taper Gold, while ProTaper Universal and U-Files had full austenitic characteristics. Overall, larger instruments had higher torque resistance and bending load values than smaller ones, while a lack of consistency and mixed values were observed in the angle of rotation. The 0.25/.08v and 0.30/.09v instruments of ProTaper Universal and U-File had the highest maximum torques, the lowest angles of rotation, and the highest bending loads than other tested systems (P < .05). No significant difference was noted regarding the untouched root canal walls after preparation with the tested systems (P > .05). Although differences observed in the overall geometry and phase transformation temperatures have influenced the results of mechanical tests, unprepared canal surface areas were equivalent among systems. Root canal preparation systems with similar geometries might present different mechanical behaviors but equivalent shaping ability.

Remaining dentinal thickness after simulated post space preparation and the fit of prefabricated posts to root canal preparation shapes

BackgroundPost space preparation can increase the risk of experiencing perforation and root fracture. The authors assessed remaining dentin thickness after post space preparation and the fit of different prefabricated posts to root canal preparation systems in a theoretical model. MethodsTen datasets per type of tooth from cone-beam computed tomography were analyzed to determine the minimum root diameter from 5 through 13 mm from the apical foramen. The preparation shapes of 10 root canal preparation systems were calculated and compared with the root dimensions to determine the remaining dentin thickness. Eight post brands were compared with root dimensions to determine the areas where there was less than 1 mm dentin thickness. ResultsThe average root canal preparation shape produced canal diameters of 0.57 mm at 5 mm from the canal terminus and 0.94 mm at 13 mm from the canal terminus. The mean post size tip diameter was 1.03 mm, which is larger than the dimensions of the average canal preparation. Post preparation would result in less than 1 mm of dentin thickness remaining in premolars, smaller roots of molars, and mandibular incisors. The area with less than 1 mm of dentin thickness was around the post tip. ConclusionsEndosequence Fiber Post (Brasseler USA), RelyX Fiber Post 3D (3M), and Rebilda (VOCO) were the better fitting posts with the root canal preparation shapes. Practical ImplicationsMany posts would result in less than 1 mm dentin thickness. Clinicians should use posts that fit their root canal preparations to minimize dentin removal.

A Comparison of the Apical Extrusion of Debris during the Preparation of Root Canal with Medin, RaCe, and ProTaper Rotary Systems.

Statement of the Problem: The extrusion of intracanal debris is one of the challenging problems related to almost all root canal preparation systems, which may cause flare-ups and impairment in the healing process.Purpose: This study was conducted to evaluate the amount of apically-extruded debris during root canal preparation using Medin (MEDIN Co., Czech Republic) rotary system compared with two common rotary systems, including ProTaper (Dentsply Maillefer., Switzerland) and RaCe (FKG Dentaire, Switzerland).Materials and Method: In this in vitro study, Sixty mandibular premolars with single canal were randomly assigned to three groups (n=20). The root canals were prepared with Medin, ProTaper, and RaCe rotary instruments based on their manufacturers’ instructions. The debris were collected into pre-weighted Eppendorf tubes. The weight of the extruded debris was calculated by subtracting the pretreatment weight of the vials. Data were analyzed using the Kruskal-Wallis test at a 5% significance level.Results: Medin instrument caused significantly less debris extrusion in comparison with ProTaper and RaCe (p< 0.05). The differences between the ProTaper and RaCe rotary systems were not statistically significant (p= 0.752).Conclusion: Within the limitations of this in vitro study, Medin rotary system produced less apical extrusion than ProTaper and RaCe.

Evaluation of the Shaping Ability of Three Thermally Treated Nickel–Titanium Endodontic Instruments on Standardized 3D-printed Dental Replicas Using Cone-Beam Computed Tomography

Background and Objectives: The aim of the present study is to compare the efficacy of three root canal preparation systems in the shaping of 3D-printed root canal replicas of single rooted teeth. Materials and Methods: Sixty 3D-printed root canal replicas were produced and divided into three groups, each consisting of twenty samples. Each group was shaped with a different instrument: Reciproc Blue R25/08 (VDW GmbH, Munich, Gemany), WaveOne Gold Primary 25/07 (Dentsply Sirona, Ballaigues, Switzerland), and ProTaper Gold F2 25/08 (Denstply Sirona). To ensure the reproducibility of pre- and post-operative CBCT images of the root canals, the endodontic printed replicas were placed in a mould of silicon impression material. A cone-beam computed tomography (CBCT) software was used to compare pre- and post-instrumentation images collected at three levels of the root canal length: 3, 6, and 9 mm from the apical foramen. The amount of transportation, centring ability, and curvature angle after shaping were evaluated for each system. The results were statistically analysed and compared using one-way analysis of variance (ANOVA). Results: Regarding the transportation of the root canal after shaping, significant differences between groups at 3 mm (p = 0.010721) and 6 mm (p = 0.000046) were recorded in the mesio-distal direction, while in the bucco-lingual significant differences were only observed at 6 mm (p = 0.000554). Reciproc Blue removed more dentin from the mesial and buccal wall of the root canal. When evaluating the centring ability of the three systems, significant differences were observed between the groups at the level of 9 mm (p = 0.037258) in the mesio-distal direction, and at the level of 6 mm (p = 0.038197) in the bucco-lingual direction. Significant differences of the canal curvature angle after shaping were also observed between groups (p = 0.000001). Reciproc Blue straightened the curvature the most, while ProTaper Gold the least. Conclusions: All systems produced minor root canal transportation. No instrument was able to achieve a perfect centring preparation of the root canal. All systems produced a small degree of root canal straightening.

Pain assessment following endodontic treatment using two automated systems compared to manual treatment in primary molars.

Root canal treatment in primary teeth is quite difficult and time-consuming, especially canal preparation. Pain is the most common negative outcome following root canal treatment, occurring hours or days after treatment. It is an unpleasant experience for both the patient and the dentist. The objective of this study was to assess the severity and duration of pain following the endodontic treatment of primary molars with the use of rotary and reciprocating preparation systems compared to the traditional manual method. The research sample consisted of 157 asymptomatic primary lower second molars with non-vital pulp that were indicated for root canal treatment. The patients were randomly divided into 3 groups: in the 1st group, the molars (n = 52) were prepared using the manual method; in the 2nd group (n = 53), a reciprocating automated preparation system (WaveOne®) was used; and in the 3rd group (n = 52), a rotary preparation system (ProTaper Next®) was used. Pain assessment was carried out after 6, 12, 24, 48, and 72 h, and after 1 week, using a four-face facial pain scale. The manual method provided a higher pain score through 6, 12 and 24 h (p < 0.05) as compared to the 2 automated preparation systems. The intensity of pain did not vary between the 2 machine preparation systems after 6, 12 , 24, and 48 h (p > 0.05). There were no differences between the 3 methods after 72 h and after 1 week (p > 0.05). The manual method caused more pain than the other 2 preparation systems, but there was no difference between the 2 automated methods. Automated root canal preparation systems could be used to reduce the intensity of postoperative pain after the endodontic treatment of primary teeth.

Impact on Quality of Life of Patients Treated by Different File Systems for Root Canal Treatment

Abstract Introduction The outcomes of oral health conditions and therapy for those conditions are described by the term “oral health-related quality of life.” Oral health-related quality of life is recognized by the World Health Organization as an important part of the Global Oral Health Program. The study aims to compare the impact of three root canal preparation systems on patients’ quality of life and correlate postoperative pain with the impact on the quality of life. Materials and Methods A survey was performed in which 90 patients were randomly assigned to three groups based on the root canal preparation system: (1) ProTaper Gold (Dentsply, Tulsa Dental Specialties, Tulsa, Oklahoma, United States), (2) Neoendo flex (Neoendo, India), and (3) Hyflex EDM/CM (Coltene Whaledent) that included 30 participants in each group. Data collection included the implementation of a demographic data questionnaire, Oral Health Impact Profile 14 (quality of life), and visual analogue scale(pain). The questionnaire was given after root canal treatment in the first 24 hours. The data obtained were statistically analyzed. Results No significant differences were found in the quality of life among study groups. Group 1 demonstrated a highly significant difference in the postoperative pain with p value of 2.67. Conclusion Within the limitations of the present study, Protaper Gold showed a highly significant difference in postoperative pain when compared with other file systems. No significant differences were found in the quality of life among the study groups.

Development of apical root microcracks following different root canal preparation systems

Context: The most critical step in root canal therapy is cleaning and shaping of the root canal. A vast array of instruments both handheld and engine driven are available for root canal preparation. There are very few studies to compare the effect of different types of instruments on the development of apical root cracks. Hence, the aim of the study was to compare the development of apical root cracks following different root canal preparation techniques and instruments.Aims: The aim of this study is to compare the development of apical root cracks following different root canal preparation techniques and instruments.Settings and Design: This is an in vitro study.Subjects and Methods: Forty extracted mandibular premolar teeth were selected and mounted on resin blocks with simulated periodontal ligaments, after which the apex was exposed. All teeth were randomly divided into four groups; each group was earmarked for a specific technique and instrument used for root canal preparation. Digital images of external apical root surfaces of every tooth were taken before and after apical enlargement through optical microscope (×40). These images were compared, and the presence of cracks was evaluated.Statistical Analysis Used: Chi-square exact test was used to compare the four groups.Results: Overall P value was 0.167 which is not statistically significant and indicates that the proportion of teeth developing cracks was not statistically significant among the four groups.Conclusions: More cracks were developed with rotary system. However, the results were not statistically significant among the four groups.

Effects of a Novel NiTi Thermomechanical Treatment on the Geometric Features of the Prepared Root Canal System.

Objectives: This study aimed to compare the ex vivo performance of two rotary nickel–titanium (NiTi) systems with similar designs but manufactured from martensitic and austenitic alloys, the One Curve (OC) and One Shape (OS) rotary endodontic files, respectively. Methods: Forty separate mesial canals of 20 extracted mandibular molars were scanned using micro-computed tomography (CT), which were divided into 2 groups and instrumented with OC and OS, respectively. Post-instrumentation micro-CT scans were evaluated using validated computer algorithms to compare changes in canal thickness, surface area, structure model index (SMI) scores, volume of removed dentin, percentage of untreated canal surface, percentage of curvature straightening, and the amount of canal transportation. Results: Both files led to significant changes in the basic root canal geometry, with no preparation errors and no statistically significant differences. However, OC treatment resulted in significantly less curvature straightening (17.30%; 10.77%) (independent samples t test, p < 0.05) and less apical transportation (55.11 µm; 33.15 µm) (Mann–Whitney U, test p < 0.05) compared to OS treatment. Transportation values in the middle and coronal thirds were statistically similar (independent sample t-test, p > 0.05). OC treatment produced significantly less straightening and less apical transportation than OS.

The impact of minimally invasive root canal preparation strategies on the ability to shape root canals of mandibular molars

To evaluate the use of a reduced taper endodontic instrument system (Bassi Logic™ .03 taper) and expandable heat-treated system (XP-endo Shaper) on the ability to shape canals in mandibular molars, by means of microcomputed tomography (micro-CT) analysis. The Reciproc system was used as the reference for comparison. Twenty-four mandibular molars were scanned in a micro-CT, matched based on similar anatomical features and sorted into three groups (n=8 per group), according to root canal preparation system: Bassi Logic™ .03, XP-endo Shaper and Reciproc. The teeth were mounted onto a mannequin and the pulp chambers were accessed with traditional access cavities. In Bassi Logic™ .03 and Reciproc groups, mesial canals were prepared with size 25, .03 taper or R25 (size 25, .08v taper) instruments and the distal root canal with size 25, .03 taper and size 40, .03 taper or R25 and R40 (size 40, .06v taper), respectively. In XP-endo Shaper groups, all root canals were prepared with XP-endo Shaper (size 30, .04v taper). After root canal preparation, the teeth were rescanned. The percentage of untouched canal areas and the percentage of removed dentine were evaluated separately for mesial and distal root canals. The data were analysed using one-way anova and Tukey tests (P<0.05). The Bassi Logic™ .03 group was associated with a greater percentage of untouched canal areas when compared to XP-endo Shaper and Reciproc groups for mesial and distal root canals (P<0.05), but no differences were found between XP-endo Shaper and Reciproc groups (P>0.05). No significant difference was observed in the percentage of dentine removed amongst the groups for mesial and distal root canals (P>0.05). The use of a reduced taper system (Bassi Logic™ .03) during root canal preparation resulted in a greater percentage of untouched canal areas when compared to XP-endo Shaper and Reciproc instruments. No differences were observed amongst the systems regarding the percentage of dentine removed.

Micro-Computed Tomographic Evaluation of Canal Transportation and Centering Ability of 4 Heat-Treated Nickel-Titanium Systems

IntroductionThis study aimed to evaluate and compare canal transportation and centering ability of 4 different root canal preparation systems produced with thermal treatments by means of micro–computed tomographic imaging. MethodsEighty mesial canals of human extracted mandibular molars were selected based on similar morphologic parameters and were randomly assigned to 4 experimental groups (n = 20) according to the canal instrumentation technique: HyFlex CM (HCM [Coltène-Whaledent, Allstätten, Switzerland]), HyFlex EDM (HEDM [Coltène-Whaledent]), WaveOne Gold (WOG [Dentsply Sirona, Ballaigues, Switzerland]), and OneCurve (OC [Micro-Mega, Besancon, France]). The specimens were scanned before and after root canal preparation using X-ray micro-computed tomographic imaging at a resolution of 19.9 μm. Apical transportation and centering ability were then analyzed at 3 different levels: 3 mm, 5 mm, and 7 mm from the apex, representing the apical, midroot, and coronal thirds of the root, respectively. One-way analysis of variance and Kruskal-Wallis tests were used to statistically compare the groups. The significance level was set at 5%. ResultsHCM caused less canal transportation than WOG at the 3-mm level in both the buccal and lingual canals (P < .05). Also, HCM resulted in less canal transportation than WOG and OC at the 7-mm level regarding lingual canals. No statistically significant differences were recorded between the groups when the mean centering ratios were compared. ConclusionsThe 4 evaluated systems safely prepared root canals causing minimal canal transportation and producing relatively centered preparations. In terms of canal transportation, HCM performed better than WOG at the apical level and better than WOG and OC at the coronal level.

Compartive Evalution of A New Endodontic Irrigation Solution –apple Vinegar, Ginger Oil And Sodium Hypochlorite to Remove The Smera Layer by Scaning Electron Microscope Study

Introduction: A three dimensional seal is the one of main steps in the successful root canal treatment .The smear layer that has been created on the dentinal wall during root canal instrumentation should be removed by using irrigation solution . Irrigation solution should be always used with mechanical preparation of root canal system as an important part for successful endodontic treatment Aim: The aim of this in vitro study was to compare the efficacy of four irrigating solutions in removing the smear layer. Materials and Methods: A total of 40 single rooted teeth were selected and instrumented and then assigned in a random manner into 4 groups of 10 each. Each group treated with different solutions (Normal saline, Sodium hypochlorite, Apple vinegar and Ginger oil). Scanning Electron Microscope had been used to measure the effect of these materials (solutions) in removal of smear layer from three root sections (Apical, middle and coronal third of the root). Conclusion: According to the Torbinjad criteria; Apple vinegar showed the best result in smear layer removal for the whole root length and no single irrigant can accomplish all the tasks required by irrigation.

Evaluation Algorithm of Root Canal Shape Based on Steklov Spectrum Analysis.

In recent years, we have seen more and more interest in the field of medical images and shape comparison motivated by the latest advances in microcomputed tomography (μCT) acquisition, modelling, and visualization technologies. Usually, biologists need to evaluate the effect of different root canal preparation systems. Current root canal preparation evaluation methods are based on the volume difference, area difference, and transportation of two root canals before and after treatment. The purpose of root canal preparation is to minimize the volume difference and ensure the complete removal of the smear layer. Previous methods can reflect some general geometric differences, but they are not enough to evaluate the quality of root canal shape. To solve this problem, we proposed a novel root canal evaluation method based on spectrum and eigenfunctions of Steklov operators, which can be served as a better alternative to current methods in root canal preparation evaluation. Firstly, the ideal root canal model was simulated according to the root canal model before and after preparation. Secondly, the Steklov spectrum of the two models was calculated. Thirdly, based on the spectrum and the histogram of the Gaussian curvature on the surface, the weight of each eigenvalue was computed. Therefore, the Steklov spectrum distance (SSD), which measures shape difference between the root canals, was defined. Finally, the calculation method that quantifies the root canal preparation effect of root canals was obtained. Through experiments, our method manifested high robustness and accuracy compared with existing state-of-the-art approaches. It also demonstrates the significance of our algorithm's advantages on a variety of challenging root canals through result comparison with counterpart methods.

Shaping ability of different root canal preparation systems

Aim To evaluate centering ability, amount of removed dentin of hand NiTi Flex K-files, ProTaper Universal system, OneShape, and WaveOne system in curved root canals. Materials and methods Forty extracted human premolars with a range of canal curvature (21–39°) were used. Samples were randomly divided into four groups (n = 10). Group 1: NiTi Flex (control group), group 2: ProTaper, group 3: OneShape, and group 4: WaveOne Primary. Centering ability of each instrument was evaluated using superimposed standardized preinstrumentation and postinstrumentation cone-beam computed tomography images recorded at three root canal levels (3, 6, and 9 mm from the apex). Amount of removed dentin was calculated by differences between preinstrumentation and postinstrumentation root canal volumes. Results WaveOne system showed the highest mean centering ratios at all tested canal levels in both directions. Apical thirds of all groups showed the highest centering ratios while the coronal showed the lowest. ProTaper system group recorded significantly highest amount of root dentin removal compared to other groups. Conclusion Reciprocating WaveOne files had more centering ability than other tested instruments. ProTaper Universal system removed significantly high amount of dentin in comparison to other systems.

Impact of root canal preparation performed by ProTaper Next or Reciproc on the quality of life of patients: a randomized clinical trial.

To compare the impact of the two different root canal preparation systems on the quality of life of patients and correlate postoperative pain with the impact on quality of life. A randomized clinical trial was conducted with 58 patients allocated into two groups based on the root canal preparation system employed: ProTaper Next (PN) or Reciproc (R). Data collection involved the administration of a questionnaire addressing demographic and clinical characteristics, the OHIP-14 (quality of life) and a visual analog scale (pain). The latter two were the outcomes of interest and were administered in the first 24h after root canal treatment. The data were submitted to descriptive analysis, bivariate analysis, Poisson univariate and multiple regression, and Spearman's correlation test, with a 5% significance level. A greater frequency of impact after treatment was found for the items 'uncomfortable to eat food' and 'felt self-conscious'. No significant difference between groups was found regarding the severity of impact for total OHIP-14 score or any of the domain scores. The two root canal preparation systems exerted a similar impact on quality of life. Postoperative pain was correlated with impact on quality of life, affecting chewing function, self-consciousness and stress. Thus, it is important for dentists to provide care capable of preventing or treating the negative consequences of such therapy.

Micro Morphological Analysis of Prepared Root Canal System Treated with Malic Acid as a Chelating Agent: an In Vitro Study

Micro Morphological Analysis of Prepared Root Canal System Treated with Malic Acid as a Chelating Agent: an In Vitro Study

Anti-microbial Photo Dynamic Therapy (aPDT) in Endodontics: A Literature Review

Elimination of root canal pathogens is one of the main objectives for successful outcome of root canal treatment. Conventional chemo-mechanical debridement is not always successful in removing all bacteria. Adjunctive use of antimicrobial photodynamic therapy (aPDT) can be a used as a practical approach for successful elimination of all these bacteria. The aim of this review was to assess scientific literature that used various photosensitizers for bacterial reduction using aPDT methods. A search of the PubMed and Cochrane data bases using appropriate terms and keywords related to antimicrobial photodynamic therapy in endodontic disinfection was conducted. A hand search also was conducted in the preceding 5 years of several journals. Full texts of the selected articles were obtained and analyzed. A total of 177 articles published were identified at first stage of data extraction. After final screening, 41 articles were included in this review. This review summarizes the usage principles of aPDT and outlines the applications of aPDT in root canal disinfection procedures. It was concluded that aPDT should be used in conjunction with the conventional chemo mechanical debridement and disinfection of root canal system. It is critical to note that selection of photosensitizer dye, its correct delivery within the prepared root canal system, laser application with correct type of tips are predictors for successful outcome of this protocol of root canal disinfection.

A Novel Hybrid Hand Instrumentation Technique for Root Canal Preparation.

Preparation of root canal system necessitates both enlargement and shaping of the complex root canal space together with disinfection of the easily accessible and hidden areas. The present article introduces a new manual root canal preparation technique and compares it with passive step-back and step-back regarding some items such as shaping efficacy, maintenance of working length and occurrence of procedural accidents. This canal preparation technique (Bolourchi Hybrid Technique-BHT) was compared with passive step-back and step-back root through preparation of 30 extracted human mandibular and maxillary molars. Three experienced endodontists evaluated the final radiographies for following items: 1) difficulty of the case 2) shaping efficacy 3) maintenance of working length 4) time of preparation. Two-way ANOVA was used to analyze the data. Multiple comparisons were done using the Tukey's HSD. Regarding shaping efficacy and maintenance of working length, BHT group showed significantly higher scores and scores for step-back group were significantly the lowest. The difference between BHT group and passive step-back on these items was not significant. No significant differences were found between the techniques in other assessed criteria except for occurrence of procedural accidents which was significantly higher in step-back group. Considering the advantages of this novel technique as well as its comparability to the present routine techniques, it can be considered as an available root preparation technique for teaching in dental schools.