K-type Files Research Articles

Topography of root-end surface after freehand and three-dimensional-guided apicoectomy procedure: A scanning electron microscope study.

Dentinal microcracks formed during apical resection may lead to increased susceptibility to root fracture and improper sealing of apical preparation that may negatively influence the outcome of endodontic microsurgery. This study was performed to analyze the root-end surface for dentinal microcracks using a scanning electron microscope (SEM) after resection with high-speed bur and trephine drill. Thirty extracted single-rooted maxillary premolar teeth were selected and randomly distributed into two groups (n = 15). Working length was established using a #15 K-type file. Canals were prepared with a rotary Ni-Ti system to size 30/0.06 using endomotor, irrigated with 3% sodium hypochlorite, dried with paper points, and obturated with gutta-percha cones using a single-cone technique. All samples were mounted on preformed molds and poured using a mixture of sawdust and gypsum. In Group A; tungsten carbide bur was used to perform a freehand apicoectomy. In Group B; a trephine drill was used with a three-dimensional guide to perform 3 mm of root resection. Apicoectomy was performed in both groups under a dental operating microscope. Resected root ends were inspected for microcracks using SEM. The Shapiro-Wilk and Mann-Whitney U-test were used for statistical analysis. Microcracks were observed in all samples in both study groups. Trephine drill produced more microcracks on the resected root surface compared to the use of high-speed tungsten carbide bur with a statistically significant difference (P < 0.05). The trephine drill used during targeted endodontic microsurgery produced more microcracks on the resected root dentine surface compared to the high-speed tungsten carbide bur used during freehand apicoectomy.

Evaluation of the dentinal wall adaptation ability of Mineral Trioxide Aggregate Fillapex, EndoSequence BC, and AH Plus sealers using Scanning Electron Microscope: An in vitro study

ABSTRACT Introduction: The present study was conducted to evaluate the dentinal wall adaptation ability of different root canal sealers (mineral trioxide aggregate Fillapex [MTA], EndoSequence BC [ESBC] Sealer, and AH Plus) using a scanning electron microscope (SEM). Materials and Methods: Forty-five extracted single-rooted human maxillary incisor teeth were selected and divided into three equal groups (n = 15). Working length was established using a #15 K-type file. Canals were prepared with rotary Ni–Ti system to size 30/0.06 or 40/0.06 file using endomotor at 250 rpm, irrigated with 17% ethylenediaminetetraacetic acid, 3% NaOCl, and normal saline solution, and dried with paper points. Prepared canals were obturated with gutta-percha cones using the single-cone technique and appropriate sealers. Specimens were stored in saline solution at 37°C for 48 h and evaluated using a SEM. Statistical Analysis: Unpaired t-test, one-way analysis of variance, and post-hoc tests verified the differences between groups and were considered significant at alpha = 5%. Results: None of the specimens showed a gap-free interface. Gaps compared between MTAF and ESBC did not show any statistically significant differences (coronal [P = 0.9757], middle [P = 0.5464], and apical [P = 0.2136] thirds). However, gaps found at the interface of sealer and dentinal wall in root canals filled with AH Plus showed extremely statistically significant differences when compared with MTAF and ESBC (P &lt; 0.0001). Conclusion: Specimens obturated with MTAF and ESBC Sealer showed smaller gaps on SEM analysis than specimens filled with AH Plus.

How Does Intentional Apical Foraminal Enlargement Affect the Foramen and Root Canal Morphology?

IntroductionThis study assessed the effect of intentional foraminal enlargement on the foramen and the apical root canal morphology. MethodSixty mesial roots of mandibular molars were scanned by micro-computed tomography. Their apical foramina were photographed with a stereomicroscope before and after preparation. Three groups were formed (n = 20) according to the working length (WL). G-1: foramen - 1 mm; G0: foramen; and G+1: foramen + 1 mm. Each group originated 2 subgroups (n = 10): G-1: Buchanan's patency (size 10 K-type file) and foraminal debridement (sizes 20, 25 and 30 K-type files); G0 and G+1: rotary foraminal enlargement (ProDesign S size 25/.08) or reciprocating foraminal enlargement (R25). The area, perimeter, transportation, and noninstrumented walls of the foramen were evaluated. The root canal transportation and the centering index of preparation at 1, 3 and 5 mm from the foramen were also assessed. Data were compared statistically (α = 5%). ResultsThe instruments used at the foramen and 1 mm beyond promoted foraminal enlargement and transportation. Regarding NIW, there was no difference between mechanized foraminal enlargements performed at the foramen or 1 mm beyond, similar to the manual foraminal debridement group (P > .05). There was no difference in transportation and centralization at 1-, 3-, and 5-mm apical levels, regardless of the instrumentation systems. ConclusionMechanical preparation at the foramen, or 1 mm beyond, resulted in foraminal enlargement, transportation and were not able to touch all root canal walls that delimit the foramen.

Using manual versus mechanized glide path instruments and ProTaper Gold versus ProTaper Next systems in curved canals: micro-CT study.

The aim of this study was to evaluate the root canal shaping effect of ProTaper Gold (PTG) versus ProTaper Next (PTN) instrumentation systems, and of a manual #15 K-type file (K15) versus the ProGlider (PG) mechanized instrument for glide path creation, in severely curved mesial canals. Twenty-four mandibular molars with two separate mesial canals were anatomically matched using computed tomographic scanning, and then divided into two groups (n=12) according to the glide path instrument used, either K15 or PG. In all teeth, the PTG system was used to prepare the mesiobuccal canal, and the PTN, the mesiolingual canal. The teeth were scanned by computed microtomography, before and after root canal preparation, and the values of the initial volume, final volume, volumetric variation, untouched walls, and canal transportation variables were determined. The data were analyzed using the two-way ANOVA test, and the Tukey test for multiple comparisons. There was no significant difference among the study groups regarding volumetric variation or root canal transportation, either in the cervical, middle or apical thirds, or in the entire root canal (p>0.05). In the apical third, the percentage of untouched walls was significantly higher in groups using K15 than in those using PG (p<0.05), namely 33.144% and 23.285%, respectively, irrespective of the instrumentation system. In the other regions, there was no difference between K15 and PG regarding this variable. It was concluded that PG was associated with a lower rate of untouched walls in the apical region than K15.

Removing Fractured Endodontic Files with a Tube Technique-The Strength of the Glued Joint: Tube-Endodontic File Setup.

One recommended technique for removing broken root canal instruments is to glue the fragment into a cannula adapted to it (i.e., the tube technique). The aim of the study was to determine the influence of the adhesive kind and length of the joint on the breaking force. During the investigation, 120 files (60 H-files and 60 K-files) and 120 injection needles were used. Fragments of broken files were glued into the cannula using one of three materials: cyanoacrylate adhesive, composite prosthetic cement, or glass ionomer cement. The lengths of the glued joints were 2 and 4 mm. After the polymerization of adhesives, a tensile test was carried out to find a breaking force. The results were statistically analyzed (p < 0.05). For 4 mm lengths of glued joints, the breaking force was higher than for 2 mm for both file types (K and H). In the case of K-type files, the breaking force was higher for cyanoacrylate and composite adhesives than glass ionomer cement. For H-type files, no significant difference in joint strength was found between binders at 4 mm, while at 2 mm, a much better connection was obtained for cyanoacrylate glue than prosthetic cements.

Effectiveness of three different rotary systems in removing gutta percha from root canals

Background: The present study was conducted for comparing the effectiveness of three different Rotary systems in removing gutta percha from root canals. Materials &amp; methods: 30 single rooted freshly extracted, mandibular premolars were collected and stored in 10% formalin until further use. Crowns of selected teeth were decoronated using diamond disc to standardize the working length to 16 mm for each specimen. Access preparation was done on each tooth and a size 10 K-type file was inserted into the canal until it was visible at the apical foramen to ensure that the canal was patent. Afterwards, all the specimens were randomly divided into three study groups according to type of retreatment system. Group A: ProTaper Universal retreatment Ni–Ti rotary instrumentation system, Group B: Mtwo retreatment Ni–Ti rotary instrumentation system, and Group C: R-Endo Ni–Ti rotary instrumentation system. After tooth splitting, each half of every specimen was separately imaged. Digitized images of each third of the root canal of each half of every specimen were obtained and evaluated.

Micro-CT Study of the In Vivo Accuracy of a Wireless Electronic Apex Locator

IntroductionThis study aimed to compare the in vivo accuracy of Wirele-X and RootZX II electronic apex locators (EALs) in determining the position of the major foramen using micro–computed tomography (micro-CT) as the analytical tool. MethodsEleven vital teeth planned for extraction from 5 patients were used. After conventional access cavity preparation, root canals were flared and negotiated up to the apical third with sizes 08 and 10 K-files followed by irrigation with 2.5% NaOCl. K-type files were used to determine the working length of the selected canals using Root ZX II and Wirele-X apex locators until their numeric displays read “0.0.” After fixing the silicon stop to the file, teeth were extracted and imaged in a micro-CT device using a double-scan protocol. Image stacks, with and without the file in the root canal, were then co-registered and the measurement error calculated as the absolute difference between the tip of the file and the major foramen. Positive and negative values were recorded when the file tip was detected beyond or short of the major foramen, respectively. Accuracy was determined on stable measurements within ± 0.5 mm when the file tip did not extend beyond the major foramen. The χ2 test was applied to compare the ability of the EALs to detect the position of the major foramen, and the t test for dependent variables was used to verify differences in the 2 measurements obtained in each tooth. Significance level was set at 5%. ResultsWithin a tolerance level of ± 0.5 mm, no significant differences were observed between the tested EALs regarding the absolute distance values (P = .82) or in their ability to detect the position of the major foramen (χ2 = 0.2588; P = .6109). The accuracy of the Root ZX II and the Wirele-X apex locators within ± 0.5 mm were 81.8% and 90.9%, respectively. ConclusionsRoot ZX II and Wirele-X performed similarly regarding the in vivo detection of the major foramen. Using strict criteria, the accuracy of the Root ZX II and the Wirele-X apex locators were 81.8% and 90.9%, respectively.

FARKLI NİKEL-TİTANYUM DÖNER ALET SİSTEMLERİNİN FARKLI KİNEMATİKLERDE KULLANIMININ ENDODONTİK TEDAVİ GÖRMÜŞ KÖKLERİN KIRILMA DİRENCİNE OLAN ETKİSİNİN İNCELENMESİ

Amaç. Çalışmamızın amacı ProTaper Universal (PTU), ProTaper Gold (PTG), Twisted File Adaptive (TFA) ve WaveOne (WO) NiTi Döner Alet sistemlerini farklı kinematiklerde kullanarak yapılan kök kanal şekillendirilmesinin dişlerin kırılma dirençlerine olan etkisini araştırmaktır. Gereç ve Yöntem. Tek köklü ve tek kanallı 160 adet alt kesici dişler seçildi. Dişler mine-sement birleşim yerinden ayrıldıktan sonra örnekler 8 gruba bölündü (n=20). Grup 1 hariç diğer gruplarda 10 K-tipi eğe kök kanallarında ilerletildi ve bu boydan 1 mm çıkartılarak çalışma uzunluğu belirlendi. 15 K-tipi eğe ile kayma yolu oluşturuldu. Kontrol grubunda köklere hiçbir şekillendirme işlemi yapılmadı. WO eğeleri sadece resiprokasyon hareketinde kullanıldı. Diğer eğeler ise hem üretici talimatlarındaki hareketle hem de resiprokasyon hareketiyle kullanıldılar. Örneklere periodontal ligamentleri taklit etmesi amacıyla elastomerik ölçü maddesi kullanıldı. Daha sonra Universal test cihazında 1mm/ dakika hızla örneklere kuvvet uygulandı. Örneklerde kırılmaya neden olan maksimum kuvvet değerleri ( F-Max) belirlendi ve sonuçlar tek yönlü varyans analizi (ANOVA) ve post-hoc LSD testleri kullanılarak istatistiksel değerlendirilmeye tabi tutuldu. (P<0.05) Bulgular. Kontrol grubu en yüksek kırılma direncine sahipti ve PTU, PTU resiprokasyon ve PTG ve PTG resiprokasyon sistemleriyle arasında istatistiksel açıdan anlamlı fark vardı. (P<0.05). TFA, TFA resiprokasyon ve WO grupları ile kontrol grubu arasında köklerin kırılmaya karşı dirençleri açısından istatistiksel olarak anlamlı fark yoktu (P>0.05). Sonuç. Çalışmamızda rotasyon veya resiprokasyon hareketiyle kök kanalları genişletilmesinin dişlerin kırılma direncinde bir fark yaratmadığı görülmüştür fakat PTU ve PTG gruplarının dişlerin kırılma dirençlerini azalttığı sonucuna varılmıştır. Anahtar Kelimeler: ProTaper, Adaptive hareket, Rotasyon, Resiprokasyon Evaluation of the Effect of Different Nickel-Titanium Systems by Using Different Kinematics on the Fracture Resistance of Endodontically Treated Roots ABSTRACT Aim. The aim of our study is to investigate the effect of the preparation on the fracture resistance of teeth by using ProTaper Universal (PTU), ProTaper Gold (PTG), Twisted File Adaptive (TFA) and WaveOne (WO) NiTi rotary instrument systems in different kinematics. Material and methods. 160 mandibular incisor teeth with single root and single canal were chosen. After the teeth were separated from the cementoenamel junction, the roots were divided into eight groups (n=20). All groups except for group 1, the working length of the root canals were determined by inserting a size 10 K-type file into the root canal terminus and subtracting 1 mm from this measurement. A glide path was done via a size 15 K-type file. In the control group, the root canals were not prepared. WO files were used only in the reciprocating motion. Other files were used both with the movement in the manufacturer's instructions and with the reciprocating movement. The periodontal ligament was simulated by using elastomeric impression material. Vertical loading was carried out with a universal testing machine at 1 mm/min crosshead speed. The maximum force at fracture (F-max) was recorded for each root and the data were analyzed statistically by one way analysis of variance (ANOVA) and post-hoc LSD tests (P<0.05). Results. The control group presented the highest fracture resistance and differed significantly from PTU, PTU reciprocation, PTG and PTG reciprocation groups (P<0.05). There were no significant differences in the fracture resistance between control group, and TFA, TFA reciprocation and WO groups (P>0.05). Conclusion. In our study, it was observed that the root canal preparation did not make a difference in the fracture resistance of the teeth by rotation or reciprocation movement, but it was concluded that PTU and PTG groups reduced the fracture resistance of the teeth. Key Words: ProTaper, Adaptive motion, Rotation, Reciprocation

Analysis of microflora in dentinal tubule by denaturing gradient gel electrophoresis

This study was performed to apply denaturing gradient gel electrophoresis to microbiological examination of endodontic infections. The method was used to assess the bacterial communities in dentinal tubules. Samples were collected using #15, #35, and #60 K-type files from five infected root canals during treatment. Deoxyribonucleic acid(DNA) was extracted from the samples, and 16S ribosomal DNA was amplified by PCR using universal primers. The polymerase chain reaction(PCR) products were separated in the denaturing gel and band patterns were compared between the deep (#60 file) and superficial layers (#15 file) of the dentin. The major bands were then excised and DNA fragments in the gel were cloned and sequenced. The sequence data were subjected to BLAST search in the GenBank database for determination of bacterial species or closest relatives. In three root canals, similar band patterns were observed in both superficial and deep layers of the dentin, while several specific bands remained in the deep layer in two roots. The bacteria isolated from the deep layers were Porphyromonas gingivalis, Olsenella profuse, Atopobium rimae, and Prevotella, Flexistipes, Firmicutes, Peptostreptococcus, Dialister, and Eubacterium spp. Unlike previous studies, gram-negative anaerobic rods were isolated from the deep layers. Clone library analysis was simultaneously performed and similar results were obtained. The method utilized here will be useful for microbiological examination of endodontic infections. In addition, although it is still unknown whether they were viable, this study demonstrated the presence of gram-negative rods in dentinal tubules.

Scanning Electron Microscopic and Dye Penetration Evaluation of Hand Instrumentation Techniques on Formation of Smear Layer in Root Canal Preparation: An In vitro Study.

Aims and Objectives:The present study was undertaken for evaluating various hand instrumentation techniques with different instruments in the formation of smear layer.Materials and Methods:One hundred and seventy-five extracted mandibular molars were collected and were cut at cementoenamel junction. Afterward, the distal roots were separated. Working length was determined, and roots were divided into five equal groups with 35 roots in each group as follows: Group A: K-type files with conventional step-back technique, Group B: Canal Master U instrument with clockwise–counterclockwise rotation, Group C: Flex-R® files with clockwise–counterclockwise rotation, Group D: FlexoFiles® with conventional step-back technique, and Group E: Nickel titanium files with conventional step-back technique. Biomechanical preparation was done according to their respective groups. The teeth in various groups were scanned under scanning electron microscope and scoring was done. All the results were analyzed by SPSS software version 17.0.Results:Scanning electron microscopic results indicated that apparently there seems to be a significant difference in the scoring of the smear layer between each group at all the three levels, but the difference was statistically nonsignificant. Microleakage was present in all the samples. Nonsignificant results were obtained while comparing the microleakage in between different the groups. However, microleakage was highest in Group D.Conclusion:The amount of smear layer is maximum at the apical third and lesser in the middle third followed by the coronal third in all the groups. All the samples showed microleakage to a varying extent.

Magnetic Resonance Imaging for Assessment of Endodontic Instruments’ Precision during “L-Shaped” Model Root Canals Preparation

The purpose of the mechanical root canal preparation is to clean it and give it the right shape. The preparation should be carried out in a way that maintains the original curvature and initial orientation of the apical end. Insufficient root canal preparation may prevent effective chemical decontamination and obturation to the full working length. The study aims to evaluate the shaping ability and effectiveness of the NiTi rotary and reciprocating endodontic instruments, compared to standard hand files using magnetic resonance imaging based on spin echo. Material and methods: A comparative study of severely curved root canals’ shaping abilities using three NiTi systems and K-type hand files was performed, with 40 training “endo-blocks” presenting with “L-shaped” canal. The root canal topography and geometry “before” and “after” mechanical preparation obtained by the magnetic resonance imaging based on the spin echo was used. The main measurement was made using the RARE sequence, with slice thickness reduced to 100 micrometers. In order to improve the signal-to-noise ratio, NA = 25 was used. To minimize the measurement time, the field of view was limited to a cuboid 17 × 16 × 3 mm, with a resolution of 33 × 31 × 100 micrometers. Each 3D image consisted of 512 × 512 × 30 voxels. The imaging plane has been selected in such a way as to fully illustrate the course of curvature of the model root canal. For TR = 5 s and effective TE = 36 ms, TA was 1.5 h. Measurements were performed twice, before and after the preparation of endo-blocs with a selected type of endodontic tools. Results: The use of rotary NiTi instruments caused a substantial alteration in the curvature topography and angle of the canals and change in the curvature length. The substantial discrepancy was observed during the preparation of simulated root canals with the reciprocating instruments and the use of WaveOne files led to the largest volume variation. No dependence between the amount of material removed and the measured intracanal side was observed when NiTi instruments were used. Preparation with hand K-type files revealed a relationship between the measuring side and the amount of material removed, with the lower values obtained for the canals’ internal curvatures. Conclusions: All the studied endodontic instruments allow a safe preparation of curved root canals in simulating in vivo conditions. The abbreviation of original root canals topography does not seem to be significantly altered following mechanical preparation of simulated, severely curved root canals. The spin echo-based magnetic resonance imaging technique can be utilized for visualization of the internal topography of the root’s canals in vitro before and after their mechanical preparation in in vitro conditions. In the future, magnetic resonance microscopy may become a diagnostic tool supporting the work of a clinician.

Cleaning of endodontic files with and without enzymatic detergent by means of the manual method versus the ultrasonic method: An experimental study.

ABSTRACTAim:The aim of this article is to evaluate the cleanliness level achieved with and without the application of enzymatic detergent for the manual method versus the ultrasonic method, applied to Flexoreamer K-type files No. 25, No. 30, and No. 35.Materials and Methods:192 K-type Flexoreamer files were divided into four categories: A1 (ultrasonic method with enzymatic detergent), A2 (ultrasonic method without enzymatic detergent), B1 (manual method with enzymatic detergent), and B2 (manual method without enzymatic detergent). Each category was randomly distributed in three groups of 16 files each (No. 25, No. 30, and No. 35). The files were used for biomechanical instrumentation of the root canal in premolars. The active part of the files was examined under a stereomicroscope, considering four cleaning levels: 4 (100% cleanliness), 3 (95–99% cleanliness), 2 (85–94% cleanliness), 1 (75–84% cleanliness), and 0 (less than 75% cleanliness). For hypothesis testing, the Mann–Whitney U-test was used to differentiate between techniques, and the Kruskal–Wallis multiple comparison test was used to compare pairs of files within each cleaning method.Results:When using enzymatic detergents, the manual and ultrasonic methods did not show significant differences when comparing each group of the files analyzed (P > 0.05). However, when comparing the cleaning level without enzymatic detergent between the manual and ultrasonic methods, we observed that it obtained a superior result when compared with the manual method for each type of file: No. 25 (P = 0.021), No. 30 (P < 0.001), and No. 35 (P < 0.001). Both methods achieved a significantly higher level of cleaning with the application of the enzymatic detergent (P < 0.05) than without applying it.Conclusion:The ultrasonic cleaning method proved to be the most effective method for the removal of biologic waste when compared with the manual method using a nylon brush. However, there was no significant difference between these two methods when enzymatic detergent was used.

In Vitro Comparative Study Of The Amount Of Apically Extruded Debris During Root Canal Preparation Using One Shape, Two Shape and Revo-S NiTi Rotary File Systems

Aim: To compare the amount of apically debris extruded following root canal preparation with One Shape, Two Shape and Revo-S NiTi rotary file systems.Materials and Methods: Forty five extracted mandibular human first molars were selected nearly 20 to 22 mm of length average. The access cavities were prepared and the MB canals were localized and explored with a size 10 K-type file. The distal roots of all teeth were amputated to the cervical level and their orifices were sealed with glass ionomer filling material. The teeth were radiographed with a file in MB canal, and the canals with a curvature degree 10 to 20 were included in this study. Apically extruded debris was collected in pre-weighted collector tubes by 10-4 precision microbalance. The teeth with the collector tubes were randomly assigned to three groups, fifteen for each. Group I, MB canals were prepared by using One Shape, Group II, MB canals were prepared by using Two Shape and Group III, MB canals were prepared by using Revo-S NiTi rotary files to the tip sizes 25 and taper of 0.06. Irrigation was performed with bi-distilled water in exactly the same manner for all the specimens with 27-G irrigation needle. All tubes were put in a receptor and were taken to an incubator where they were stored at 37oC for 21 days until the debris was dry. The tubes were then reweighted using the same analytical balance. The difference between pre-weighted tubes and the weight after preparation were tabulated and compared statistically. Results: The lowest amount of apically extruded debris was found in Two Shape group followed by One Shape group, and the highest amount was found in Revo-S group. Comparison between the mean values of the three groups revealed a statistical significant difference at 5%.Comparison between the Two Shape group and One Shape group revealed a statistical significant difference at 5%. Comparison between the Two Shape group and Revo-S group revealed also a statistical a significant difference at 5%. But no statistical significant difference revealed when comparing the One Shape and Revo-S groups at 5% level of significance.Conclusion: The Two Shape showed significantly the lowest amount of apical debris extrusion followed by One Shape and the highest amount showed by Revo-S.

ANATOMICAL STUDY OF THE MESIOBUCCAL ROOT IN MAXILLARY FIRST MOLAR WITH DIFFERENT METHODS IN EGYPTIAN POPULATION

Aim: to study the canal anatomy and its variations of mesiobuccal root of maxillary first molar using visual, CT, CBCT, and staining and clearing. Materials and Methods: Three hundred extracted permanent maxillary first molar teeth were selected for this study. Mesio-buccal roots were resected 1 mm coronal to the trifurcation level. The orifices of the canals were located with a size 10 K-type file which was passively advanced into the canals until the tip of the instrument penetrated the apical foramen for visual examination. The number of orifices and apical foramina in each root were recorded. All roots were embedded in a sheet of pink wax with vertical orientation and arranged in their numbers to facilitate three dimensional CT and CBCT scan and the data were stored on a magnetic optical disc. Both, CT and CBCT images were assessed by a calibrated dental radiology specialist blinded to the order of roots using Vitrea 2 V 3.8 imaging software. India ink was injected into the orifices of the root canals with a plastic disposable endodontic irrigating syringe with a 27-G needle with suction tip which was placed at the root apex to draw the ink through the root canal system. All roots were decalcified with 5% hydrochloric acid for three days, dehydrated in ascending concentrations of ethanol (75%, 85%, 96% and 100%) for four hours each, and transparent specimens were obtained by immersing the dehydrated roots in methyl salicylate solution, in which the roots were stored until they were examined. The data regarding root canal morphology of each sample from all evaluation methods were tabulated and compared statistically. Results: There were significant differences between the four methods used for studying the root canal anatomy of mesiobuccal root of first maxillary molars as regarding the number of canals, number of orifices, number of apical foramina, presence of lateral accessory canals and intercanal communications. Roots with three canals and three orifices and opened apically with two foramina showed no significant differences between the four methods. Also, with Kappa test, there was good and fair agreement between CBCT & CT and CBCT & staining and clearing respectively. Conclusion: the most detailed information can be obtained in-vitro by staining and clearing and high resolution CT and CBCT methods which are commonly used as a diagnostic aid in clinical endodontics

Topographic Features of Five K-file Brands in Iranian Market: A Scanning Electron Microscopic Study.

Introduction:Endodontic files which are used to clean and shape the root canal space differ from each other regarding technical specifications. Recently, K-type files are repeatedly studied on their cutting efficiency. This study aims to evaluate the tip design and cutting efficiency of 5 brands of K-files, available in Iran dental market (naming Dentsply, Thomas, Mani, Perfect and Larmrose). Methods and Materials:In this descriptive study, topographic features of file tips were investigated by the scanning electron microscope (SEM). Those features included tip symmetry, tip design, tip angle, and the distance from the tip to the lowest flute. SEM images (×250 magnification) of files were prepared. Statistical tests (Fisher's exact test, Chi-square, ANOVA, and t test) were used and P<0.05 was considered as significant.Results: Dentsply files had the most number of morphologically pyramidal sharp tips and the greatest tip angles. However, Larmrose files were the most frequent files having cutting sharp tips. Symmetrical tips existed among 100% of Dentsply and Mani brands. No significant differences were found with respect to distance from the file tip to the lowermost flute between different file brands of this study (P=0.2, One way ANOVA). Conclusion:Dentsply and Mani files possessed the most symmetrical tips and greatest tip angles. With respect to tip length, all 5 brands were satisfactory. However, neither of 5 brands evaluated topographically were outstanding in every aspect.

Prevalence of major apical foramen mismatching the root apex in root canals of human permanent teeth

The periapical radiograph is used to determine the working length in endodontic treatment. However, this radiograph does not define the position of the major apical foramen. Objective: This ex vivo laboratorial study aims to determine the prevalence of the major apical foramen mismatching the root apex in human permanent teeth, because when present, this mismatch makes the radiographic method inaccurate for determining the working length. Material and methods: This study used 400 human permanent teeth: 100 incisors, 100 canines, 100 premolars, and 100 molars, totalizing 634 canals (Ethics Committee, Federal University of Ceará #263/10). The access and negotiation of the root canals were performed with K-type files #10 and #15 until the tip of the instrument were visible at the root foramen through 5-fold magnifying glass. Periapical radiographs were performed on bucco-lingual incidence for single-rooted teeth; the incidence angle was changed for multi-rooted teeth. The films were processed and then analyzed by three calibrated examiners (Kappa 80%). Descriptive statistics and chi-square test were used for analyzing of the results. Results: The prevalence of major apical foramens mismatching the root apex was 19.72% of the canals studied. The incisors showed the lowest prevalence (9%, p&lt;0.05) while the highest prevalence was seen in canine teeth (28%). Conclusion: According to the methodology applied, the prevalence of major apical foramens mismatching the root apex foramens make necessary an adjunct method for determining the working length, because it alone was not capable of determining the foramen position.

Ex vivo model for studying polymicrobial biofilm formation in root canals

Endodontic disease has mainly a microbial origin. It is caused by biofilms capable of attaching and surviving in the root canal. Therefore, it is important to study the conditions in which those biofilms grow, develop and colonize the root canal system. However, few studies have used natural teeth as models, which would take into account the root canal anatomical complexity and simulate the clinical reality. In this study, we used human premolar root canals to standardize &lt;em&gt;in vitro&lt;/em&gt; biofilm optimal formation conditions for microorganisms such as &lt;em&gt;Enterococcus faecalis&lt;/em&gt;, &lt;em&gt;Staphylococcus aureus&lt;/em&gt; and &lt;em&gt;Candida albicans&lt;/em&gt;. 128 lower premolars underwent canal preparation using K-type files, and were treated with 5.25% sodium hypochlorite and EDTA. Samples were inoculated with microorganisms and incubated for 15, 30, 45, and 60 days under anaerobiosis (CO2 atmosphere) and aerobiosis. Microorganism presence was confirmed by Gram staining, cell culture, and electron microscopy. Exopolysaccharide matrix and microorganism aggregation were observed following 15 days of incubation. Bacterial growth towards the apical third of the root canal and biofilm maturation was detected after 30 days. CO2 atmosphere favored microbial growth the most. &lt;em&gt;In vitro&lt;/em&gt; biofilm maturation was confirmed after 30 days of incubation under a CO2 atmosphere for both bacteria and yeast.

Evaluation of Bacteriological Profile in the Apical Root Segment of the Patients with Primary Apical Periodontitis.

Apical periodontitis usually results from bacterial accumulation and contamination occurring in the root-canal system, and extending beyond the apical foramen to involve the periapical tissues. Literature has a paucity of the studies that stress on the division and analysis of the pulp canal segments. The reason for this disparity might be the technique used for collecting the samples from the pulp canals. Hence, we carried out the present study to evaluate the microbial flora in the apical part of the roots with necrotic pulp canals. The present study included the assessment of 40 freshly extracted teeth that had necrotized pulpal tissue along with the presence of periapical periodontal lesions. Removal of the soft tissue lesions attached to the root portion of the teeth along with apical periodontal lesions was done with the help of scalpel blade, after rinsing them with a sterile solution of saline. Thorough cleaning of the root surfaces was done with hydrogen peroxide followed by rapid disinfection with the help of sodium hypochlorite at varying concentrations. Sectioning of the root portion of all the specimens with the help of a disk was done perpendicular to the long axis of the teeth at a distance of roughly 5 to 6 mm from the teeth's apicalmost point. Cryotubes were used for transferring the specimens of apical portions containing 1 mL of buffer and were subjected to immediate frozen processing at a temperature of -20°C. A 10 K-type file was used for the initial collection of the samples followed by subsequent incubation of the files and paper pints in the incubation cabinet. Subsequent deoxyribonucleic acid (DNA) extraction from the samples was done following the procedure described by Siqueira et al. Paster et al's modification of the reverse-capture checkerboard assay was used in the present study. Semiquantitative data were used for overcoming the difficulties arising due to obtaining the counts of the polymerase chain reaction (PCR)-based analysis of specimens. A positive result for the 16S ribosomal ribonucleic acid (rRNA) gene primer was observed only in two examined specimens of all the samples of the apical portion of the root canals in the present study. Negative result was shown by all the control group specimens, which were sterile samples. Presence of bacteria was confirmed by PCR in 38 out of 40 examined specimens. Amount of bacterial taxa, out of these 24 samples, ranged up to 6. Pseudoramibacter alactolyticus, Porphyromonas endodontalis, Dialister oral species, Bacteroidetes species, Streptococcus species, Olsenella uli, Synergistes species, Fusobacterium nucleatum, Parvimonas micra, Treponema denticola, and Filifactor alocis were the specific species detected. Bacteroidetes species was the only species that were detected at levels at or above 105. Heavy bacterial infections were noticed in more than 45% of the cases at the periradicular part of the root canals. Microbial flora of the apical segment of the root with necrotized pulp tissue comprises a vast variety of pathogenic bacteria. For better prognosis of the treatment of such cases, adequate knowledge of the microbial flora of the root, especially the apical portion is necessary.

Endodontic treatment of maxillary lateral incisor with internal root resorption using a hybrid instrumentation technique - case report

Several factors influence the cleaning and shaping capacity of instrumentation techniques, such as internal resorption areas. Internal root resorption contributes to failure of endodontic treatment, since debris may remain attached to dentine walls, and the instruments are not able to completely remove them. This paper reports a clinical case of endodontic treatment of a tooth with internal root resorption using a hybrid instrumentation technique. After clinical and radiographic examinations, pulp necrosis with periapical lesion, and the presence of an internal root resorption were diagnosed. Biomechanical preparation began with glide path creation with sizes 15 and 20 K-type files. Apical third instrumentation was performed with rotary ProFile files #25.04 up to #35.04, followed by root canal filling. The case was followed-up for twelve months. Progressive bone repair was observed radiographically. Despite the presence of internal root resorption, the results achieved with the hybrid technique suggest effectiveness in this clinical case solution.Keywords: Dental Pulp Cavity; Endodontics; Root canal therapy.

Peregrination of endodontic tools-past to present

The clinical practice of yesterday's endodontics becomes the heresy of today, and today's endodontic practice becomes the heresy of tomorrow. The history of endodontics begins in the 17 th century. Since then, there have been numerous advances and developments, and research has proceeded continuously without pause. The manufacture of the first instruments for endodontic use dates back to 1875. These early instruments were made by hand from thin steel wires, and they performed the function of modern barbed broaches. In 1955, Ingle was the first to express the need for standardization of canal instruments. In 1965, the American Association of Endodontists adopted the terminology and nomenclature of the proposed standardized system. For many years, the standard cutting instruments have been the reamer, the K-type file, and the Hedstroem file. Recent changes in both metallurgy and endodontic concepts have led to the introduction of a wide range of new instruments. An effort has been made here to present the journey of endodontic instruments from the past to the present.