v. 01, no. 1
Dental Press Endodontics – ISSN 2178-3713
Dental Press Endod.
v. 01, no. 1
April / May / June
Revolution in scientific information
Mankind is experiencing constant change, which causes direct repercussions in its essence. The industrial revolution was a remarkable event. The society witnesses, at the present time, the revolution of information in different segments. The speed and the way in which this information has been promoted is fantastic. The scientific globalization encourages the different levels of an academic structure.
The challenge of the moment requires a careful selection of storage and a proper interpretation. Brazil is experiencing a very favorable moment in science, within which we can mention its quality and its acceptance by the international community. Moreover, the stimulus to the development of a major project, to the entire community that brings together endodontics as a magna specialty, is born from a careful and well structured programming. The realization of this project came from the opportunity afforded by Dr. Laurindo Furquim, publisher of Dental Press, with the creation of the Dental Press Endodontics.
Therefore, the challenge of disseminating endodontic science is launched with the creation of the Dental Press Endodontics, which is composed by a team of renowned professors, researchers and specialists in endodontics in Brazil and internationally. Endodontic scientific information certainly will have a new vehicle facilitator and promoter, able to improve clinical decisions supported by scientific evidence. The Dental Press Endodontics allow the reader to renew concepts and experience the revolution in scientific informations.
Endo in Endo
Orthodontic treatment does not cause pulpal necrosis
The dental pulp has an arborized vascular system and its only blood source is represented by a delicate artery that penetrates the apical foramen. Seldom there is a vascular communication of the pulp with the periodontal ligament through the lateral canals and accessories from the lateral and apical foramina.
A NiTi rotary instrument manufactured by twisting: morphology and mechanical properties
Endodontic instruments. NiTi alloy. R-phase. Materials characterization. Mechanical tests. NiTi manufacturing methods.
Objectives: The surface morphology of TF® endodontic instruments was studied using stereomicroscopy and scanning electron microscopy (SEM). Mechanical tests were done for flexibility and microhardness. Methods: Four tapers of TF® files were used (0.04; 0.06; 0.08 and 0.10 mm/mm). The stereomicroscopy associated with the AxioVision® program was used to measure the tip angle, the helical angle, the taper and the tip diameter of the instruments. SEM was used to identify surface defects due to machining and finishing. The flexibility and the microhardness were measured with bending and microhardness Vickers tests, respectively.
Results and Conclusion: The analysis showed that the manufacturer complied with the values recommended by the ANSI/ADA standard number 28. The SEM results showed many surface defects and a distortion of the instrument helix. It was observed that the instrument flexibility changes with its taper. The forces to induce the phase transformation by stress on instruments with taper 0.04; 0.06 and 0.08 mm/mm were 100 gf, 150 gf and 250 gf, respectively. The values of Vickers microhardness of the instruments are compatible with rotary instruments manufactured by the machining process.
Effect of intracanal posts on dimensions of cone beam computed tomography images of endodontically treated teeth
Cone beam computed tomography. Artifact. Intracanal post. Post.
Objectives: This study evaluated the effect caused by intracanal posts (ICP) on the dimensions of cone beam computed tomography (CBCT) images of endodontically treated teeth.
Methods: Forty-five human maxillary anterior teeth were divided into 5 groups: Glass-Fiber Post®, Carbon Fiber Root Canal®, Pre-fabricated Post – Metal Screws®, Silver Alloy Post® and Gold Alloy Post®. The root canals were prepared and filled; after that, the gutta-percha filling was removed, and the ICP space was prepared. The post cementation material was resin cement. CBCT scans were acquired, and the specimens were sectioned in axial, sagittal and coronal planes. The measures of ICP were obtained using different 3D planes and thicknesses to determine the discrepancy between the original ICP measurements and the CBCT scan measurements.
Results: One-way analysis of variance, Tukey and Kruskall-Wallis tests were used for statistical analyses. The significance level was set at α = 5%. CBCT scan ICP measurements were from 7.7% to 100% different from corresponding actual dimensions.
Conclusion: Gold alloy and silver alloy posts had greater variations (p>0.05) than glass fiber, carbon fiber and metal posts (p<0.05). Gold alloy and silver alloy post dimensions were greater on CBCT scans than on original specimens.
Efficacy of chemo-mechanical preparation with different substances and the use of a root canal medication in dog’s teeth with induced periapical lesion
Sodium hypochlorite. Chlorhexidine. Calcium hydroxide. Endodontic infection. Root canal medication.
Objectives: to evaluate the effect of instrumentation, irrigation with different substances and the use of calcium hydroxide on bacterial load and microbiota profile in dog’s teeth with pulp necrosis and periapical lesion.
Methods: Fifty five root canals were divided into groups: I) Saline (SSL) (n=11); II) natrosol gel (n=11); III) 2.5% NaOCl (n=11); IV) 2% CHX-gel (n=11); V) 2% CHX-solution (n=11). Endodontic samples were cultured, microorganisms counted and the microbiota analyzed at different sampling times — s1, s2 and s3.
Results: At s1, the mean CFU counts ranged from 5.5 x105 to 1.5 x 106. These values dropped significantly at s2 (p<0.05). No statistical significant difference was found between s2 and s3. Changes in root canal microbiota were found at s2 and s3.
Conclusion: Regardless the use of calcium hydroxide as a root canal medication, 2.5% NaOCl and 2% CHX-gel demonstrated a potent antimicrobial activity against endododontic pathogens in vivo.
In vitro determination of direct antimicrobial effect of calcium hydroxide associated with different substances against Enterococcus faecalis strains
Environmental Microbiology. Enterococcus faecalis. Calcium hydroxide. Products with antimicrobial action.
Objective: To determinate the direct antimicrobial effects of Casearia sylvestris Swart (guaçatonga), propylene glycol, and of chlorhexidine associated to calcium hydroxide paste against 40 Enterococcus faecalis strains isolated from the oral cavity when direct contact.
Methods: After activation, the bacterial strains were suspended in sterile saline to 1.0 McFarland standard. The suspension was placed in direct contact with calcium hydroxide paste [Ca(OH)2] + pure propylene glycol, Ca(OH)2 + chlorhexidine 1% in propylene glycol, and Ca(OH)2 + guaçatonga extract in propylene glycol by covering paper points, previously contaminated for 3 minutes, with the different pastes. Antimicrobial activity was evaluated at 6, 24, 48, 72 hours, and at 7 days. After the incubation period, the points were removed from the pastes and incubated in Letheen broth at 37oC for 48 hours. Following that, 0.1ml of the Letheen broth was transferred to tubes containing brain heart infusion (BHI) broth and incubated again at 37oC for 48 hours. Turbidity was observed in the medium. After that, M-Enterococcus agar plates were seeded with BHI broth from each tube and colony growth was assessed.
Results: All the bacterial strains were inhibited by all pastes at the evaluated periods.
Conclusions: It was concluded that the addition of these substances to calcium hydroxide did not interfere with its direct antimicrobial effect.
Analysis of forces developed during root canal filling by different operators
Lateral condensation technique. Root canal filling. Condensation force.
Objectives: Endodontic procedures might contribute to the development of vertical root fracture as well as other localized defects such as craze lines or incomplete cracks in root dentine. The objective of this study was to evaluate the maximum fracture resistance and the force produced by five different operators in lateral and vertical condensation during root canal filling.
Methods: 74 human teeth, superior canines (SC) and inferior premolars (IPM) were selected. In order to determine the maximum fracture resistance during condensation, 24 teeth were submitted until failure to an axial compression load in a universal testing machine. Fifty teeth were used in order to measure the axial condensation force by means of a device developed to simulate clinical working conditions.
Results: Fracture resistance mean values in kg were: SC = 14.96±2.65 and IPM = 7.56±1.05. Mean values of force applied by each of the five operator in Kg were, respectively: 2.49; 3.75; 2.24; 2.08 and 1.18. None of the operators achieved teeth’s maximum fracture resistance during procedures.
Conclusions: Different behaviors among five professionals monitored were observed for the same technique of root canal filling. The increase in strength during condensation had no radiographic improvement of root canal filling. During the root canal filling, lateral and especially vertical condensation, must be performed with reduced apical strength and pressure, avoiding excessive and unnecessary stress to root dentin.
Root canal filling with calcium hydroxide paste using lentullo spiral at different speeds
Calcium hydroxide. Intracanal dressing. Root canal filling
Objective: This study analyzed the effectiveness of filling the root canal with calcium hydroxide paste using the Lentulo spiral at different speeds.
Methods: Thirty mandibular premolars after root canal preparation were divided in three groups. Calcium hydroxide paste was inserted in the root canals with a Lentulo spiral at 5,000 rpm (G1), 10,000 rpm (G2) and 15,000 rpm (G3). The optical density was determined by the use of the digital radiography system Kodak Dental RGV-5000.
Results: The highest optical density obtained in the apical third was in G3 and in the middle and cervical third in G1. Statistical difference (Kruskal-Wallis - Anova) was observed (p<0.05) between G1 and G3 in the apical third and G1 and G2 in the middle third. No difference was observed in the cervical third (p>0.05).0.05)>
Conclusion: Different speeds are necessary for the correct filling of the root canal with calcium hydroxide paste. The 15,000 rpm speed was more effective in filling the apical third and 5,000 rpm speed was more effective in filling the cervical and middle thirds.
Location of the apical foramen and its relationship with foraminal file size
Apical patency. Apical foramen. Endodontic instruments.
Aim: This article analyzed the location of the apical foramen and its relationship with foraminal file size in maxillary central incisors.
Methods: Eighty four human maxillary central incisors were used in this study. K-files of progressively increasing diameters were inserted into the root canal until it got snugly fit and the tip was visible at the apical foramen. The files were removed and teeth were cross-sectioned 10 mm from the root apex. The files were then reinserted, fixed with a cyanoacrylate-based adhesive, and sectioned at the same level as the root. The root apices were examined using a scanning electron microscope set at 140x magnification, the images were captured digitally and the results were subjected to Chi-square test.
Results: It was observed that 63 (75%) of the apical foramen emerged laterally to the root apex and 21 (25%) coincided with the apex. The results presented statistically significant differences (ג2=22.1; p=0.00).
Conclusions: Lateral emergence of the apical foramen is more common than coincidence of the foramen with the apex in maxillary central incisors. This anatomical characteristic may have influence on determination of the foraminal file size.
In vitro evaluation of shape changes in curved artificial root canals prepared with two rotary systems
Rotary nickel-titanium instruments. Root canal preparation. Curved artificial root canals.
The persistence of different calcium hydroxide paste medications in root canals: an SEM study
Calcium hydroxide. Intracanal medication. Vehicles.
Introduction: There is a possibility of intracanal medication remain in the root canal even after its removal prior to obturation. The present study aims to evaluate under scanning electron microscopy the persistence of residues in the root canal from calcium hydroxide medications prepared with different vehicles.
Methods: Thirty-six bovine incisors had their crowns removed, the root canals prepared and were assigned randomly to six different experimental groups, according to the intracanal medication used. Group I (control) received no intracanal medication, whereas root canals of Group II were filled with P.A. calcium hydroxide. Group III received a mixture of Ca(OH)2 and saline solution, in Group IV glycerin was used as vehicle, and Groups V and VI received Ca(OH)2 mixed with propylene glycol or polyethylene glycol 400, respectively. After one week, medication was removed, roots were split and the canals observed under the scanning electron microscope. Representative photomicrographs of the apical third of each experimental group were observed and analyzed quantitatively by means of a grid, with results expressed in percentage of canal walls covered by debris.
Results: Statistical analysis (one-way ANOVA and Tukey’s post hoc test, α=0.05) revealed significant differences between groups, indicating higher amounts of Ca(OH)2 residues in the canals where propylene glycol or polyethylene glycol were used as vehicles. The dentinal walls of the canals that received pure P.A. calcium hydroxide or its association to glycerin presented amounts of debris similar to the control group.
Conclusions: Ca(OH)2 P.A. based medications or its association to glycerin allows an easier removal from the root canal.
SEM and microbiological analysis of dirt of endodontic files after clinical use and your influence on sterilization process
Dirt. Endodontic files. Microbiological test. Scanning electron microscopy.
Objective: The aim of this study was to assess the level of cleaning of endodontic files after its use in root canals preparation and their influence on the sterilization process.
Methods: Fifty files were divided into two groups: one group of 25 files for analysis in scanning electron microscopy (SEM) for verification of cleaning and another group of 25 files for microbiological analysis in thioglycolate and BHI after sterilization.
Results: The results showed that endodontic files had different degrees of dirt on his active part through evaluation by scanning electron microscopy. The bacterial growth wasn’t detected through microbiological test after sterilization.
Conclusion: It was concluded that despite the significant presence of dirt on endodontic files in their active part, this dirt don’t interfere in the sterilization process.
Influence of cone beam computed tomography on dens invaginatus treatment planning
Dens invaginatus. Dental anomaly. Cone beam computed tomography. Endodontic diagnosis.