Simulated Internal Root Resorption Research Articles

Mechanical activation with Easy Clean device enhanced organic tissue removal from simulated internal root resorption in a laboratory evaluation

BackgroundConsidering the irregular shape of the root canal, removing inflamed pulp and granulation tissue completely from internal resorption cavities during chemomechanical preparation can be challenging. This study aimed to evaluate the effectiveness of passive ultrasonic irrigation (PUI) compared to mechanical activation with Easy Clean in the removal of organic tissue from simulated areas of internal root resorption.MethodsThe root canals of 72 extracted single-rooted teeth with oval canals were instrumented with Reciproc R25 instruments. After root canal preparations, the specimens were split longitudinally, and semicircular cavities were prepared using a round bur on each half of the roots. Samples obtained from bovine muscle tissue were weighed and adapted into semicircular cavities. The roots were reassembled and joined, and the teeth were divided into six groups (n = 12) according to the irrigation protocol: Sodium hypochlorite (NaOCl) without activation; NaOCl + PUI; NaOCl + Easy Clean; distilled water without activation; distilled water + PUI; and distilled water + Easy Clean. After irrigation protocols, the teeth were disassembled, and the remaining organic tissue was weighed. Data were analyzed by two-way ANOVA and Tukey’s post hoc test (p < 0.05).ResultsNone of the experimental protocols totally removed the bovine tissue from simulated cavities. Tissue weight reduction was significantly affected by the activation method (p < 0.05) and by irrigation solution (p < 0.05). Groups with NaOCl irrigation presented higher tissue weight loss when compared to distilled water, for all irrigation methods (p < 0.05). The use of Easy Clean resulted in the greatest tissue weight loss (42.0%—Distilled water/45.5%- NaOCl) compared to those of PUI (33.3%—Distilled water/37.7%- NaOCl) and no activation (33.4%—Distilled water/38.8%- NaOCl) (p < 0.05). However, no differences were observed between PUI and no activation groups (p > 0.05).ConclusionsMechanical activation with Easy Clean enhanced organic tissue removal from simulated internal resorption more effectively than PUI. Easy Clean for agitation of the irrigating solution is effective in removing simulated organic tissues from artificial internal resorption cavities, being an alternative to the use of PUI.

Does the activation of root canal dressings improve their filling quality on teeth with simulated internal root resorption?

This study aims to evaluate, by micro-computed tomography, the filling capacity of two root canal dressings (RCD) - Bio-C Temp and Ultracal - after different activation protocols in teeth with simulated internal root resorption. Eighty single-rooted bovine teeth were sectioned in the cervical portion, standardizing the roots at 16 mm. Then, the canals were prepared by the apex-crown technique until instrument #80 using 2mL of 2.5% sodium hypochlorite solution at each instrument change. Afterward, the roots were sectioned longitudinally, and internal root resorptions were simulated using a diamond bur 1016 at 5 mm from the root apex. Hemiroots were joined and fixed with cyanoacrylate, scanned in micro-computed tomography (micro-CT) to assess total canal volume and simulated internal resorption, and then divided by stratified randomization into experimental groups according to RCD and method of activation (n = 10): Ultracal/Syringe; Ultracal/PUI, Ultracal/XP Endo Finisher, Ultracal Easy Clean, Bio-C Temp/Syringe, Bio-C Temp/PUI, Bio-C Temp/XP Endo Finisher and Bio-C/Easy Clean. Another scanning was performed to assess the volume of voids after RCD activation methods. The ANOVA and Tukey tests compared the activation methods. Student's T-test compared the RCDs within each activation method. Initial root canal volume values were similar for all groups (P &gt; 0.05). There was no difference between activation protocols (P &gt; 0.05). Higher volumes of void spaces were observed for Bio-C Temp compared to Ultracal after all activation methods (P &lt; 0.05), except for Easy Clean (P &gt; 0.05). Due to this, it can be concluded that the agitation methods tested for the Bio-C Temp and Ultracal pastes did not improve the filling of bovine teeth with simulated internal root resorption.&#x0D;

Antimicrobial effectiveness of different irrigation activation techniques on teeth with artificial internal root resorption and contaminated with Enterococcus faecalis: a confocal laser scanning,icroscopy analysis.

This study aimed to compare the antibacterial efficacy of standard needle irrigation (SNI), EDDY, passive ultrasonic irrigation (PUI), photon-induced photoacoustic streaming (PIPS), and shock wave enhanced emission photoacoustic streaming (SWEEPS) activation on the teeth with simulated internal root resorption (IRR) and contaminated with Enterococcus faecalis (E. faecalis) using confocal laser scanning microscopy (CLSM) analyses. A total of 79 human maxillary central incisors with a single canal were selected. The canals were accessed, and then, the roots were split in the bucco-lingual direction. Artificial IRR cavities (depth of 0.8mm and a diameter of 1.6mm) were prepared using round burs and 20% nitric acid in the middle region of the root halves. The root halves were reconstructed with cyanoacrylate glue, and the canals were contaminated with a culture of E. faecalis for 30days. Root canal preparation was performed using the ProTaper Next rotary files up to X5 and 2.5% NaOCl irrigation. Teeth were randomly assigned to five groups according to the irrigation activation method (n = 15): SNI, EDDY, PUI, PIPS, and SWEEPS. The final irrigation procedures were performed using a total of 6mL of 2.5% NaOCl for each tooth with an activation time of 3 × 30s. The canals were stained with LIVE/DEAD BacLight dye and analyzed with CLSM to determine the percentages of dead bacteria in the biofilm. Two-way ANOVA and post hoc Tukey tests were used for statistical analysis (P < .05). None of the irrigation activation methods tested provided 100% bacterial elimination. There was no significant difference between the irrigation activation methods tested in terms of the percentage of dead bacteria (P > 0.05). In irrigation activation methods other than PIPS, there was no significant difference in the percentage of dead bacteria between the coronal, middle, and apical regions of the roots (P > 0.05). A higher percentage of dead bacteria was found in the middle region compared to the apical region in the PIPS (P < 0.05). Within the limitations of this study, SII, EDDY, PUI, PIPS, and SWEEPS have a similar antimicrobial effect on the teeth with IRR and contaminated with E. faecalis.

Evaluation of Debris Removal Efficacy of Conventional Syringe, Irrisafe, XP-endo Finisher File, and Photon-Induced Photoacoustic-Streaming Methods in Teeth with Artificial Internal Resorption Using Two Different Methodologies.

Objective: This study sought to evaluate the effect of conventional syringe irrigation (CSI), irrigation with XP-endo Finisher file (XP-F), passive ultrasonic irrigation (PUI), and photon-induced photoacoustic-streaming (PIPS) methods on dentine debris removal from teeth with simulated internal root resorption (IRR) cavities by using scoring and image analyzing methods. Materials and methods: Chemomechanical preparation of 88 single-rooted sample teeth was completed, they were split longitudinally and IRR cavities were prepared. Simulated debris was placed into the cavities. Four teeth were separated to serve as the negative control group. According to the final irrigation technique, 4 experimental groups were created (n = 20): Group 1, CSI; Group 2, XP-F; Group 3, PUI; and Group 4, PIPS. The amount of remaining debris in the IRR cavities was examined under a stereomicroscope. Analysis was performed using two different methodologies: (1) scoring method and (2) image analyzing method. The data were statistically evaluated by one-way analysis of variance, Kruskal-Wallis, chi-square, and Dunn tests with a significance level set as 5%. Results: In both methodologies, PIPS was found to be significantly more effective than XP-F in terms of debris removal. There was no significant difference between XP-F and PUI (p > 0.05). According to the findings obtained from the image analyzing method, PIPS and PUI groups were not significantly different (p > 0.05). Conclusions: PIPS method can be selected as an irrigation activation methodology in teeth with IRR. Considering the similar results of both evaluation methods, image analyzing programs can be used as an alternative in studies on debris removal.

Effect of Passive Ultrasonic Irrigation over Organic Tissue of Simulated Internal Root Resorption.

This study aimed to evaluate the efficacy of passive ultrasonic irrigation (PUI) on dissolving the organic tissue inside simulated internal root resorption (IRR) using sodium hypochlorite (NaOCl) or chlorhexidine (CHX). A total of 40 human lower premolars were collected based on dimensional and morphological similarities. The roots were embedded in cylinders (3 cm diameter; 2.5 cm height) of self-cured acrylic resin, and then an IRR was simulated. The specimens were divided into 4 groups (n = 10) according to irrigation protocols: group 1: CHX + PUI; group 2: CHX; group 3: NaOCl + PUI; group 4: NaOCl. The total irrigation time was 150 s at a flow rate of 5 mL/min. A tissue mass of porcine palatine mucosa was used to simulate the organic tissue, it was weighed before and after the irrigation using an analytic balance, and the difference between both readings was calculated and transferred to percentage values. Data were submitted to statistical analysis using two-way ANOVA (factors: irrigant type and with/without PUI) and Tukey's test for multiple comparisons among the experimental groups (α = 0.05). There was a significant difference in both factors (irrigant: p=0.04; PUI: p ≤ 0.001). The groups that used PUI were more effective in dissolving the organic tissue of the IRR simulation than the groups without PUI. PUI is more effective than the syringe and needle irrigation in organic tissue dissolution.

Comparison of digital image displays performance in the detection of artificial internal root resorptions lesions.

To compare the diagnostic efficacy of different devices for visualizing digital images in detecting simulated internal root resorption (IRR). 26 uniradicular human teeth were sectioned along its long axis and randomly divided into two groups. Then, they were submerged in hydrochloric acid (HCl) P.A 37% at different times to make two types of defects: Type 1 (2 hours), and type 2 (3 hours). Digital periapical radiographs were acquired in three moments: before section, after section and after immersion in acid. The images were evaluated on three different devices: 27-inch iMac Desktop, 8-inch Android Tablet, and 5.5-inch iPhone 8 Plus using a 5-point scale. The sensitivity and accuracy values were higher with the use of the Android Tablet, for both types of defects. For the values of the area under ROC curve, higher results were observed with the Android Tablet and lower results with the iMac, showing a significant difference (p < 0.05) when comparing the use of the iMac with the Android Tablet and iPhone 8, for type 1 defects. When comparing the different devices, in the evaluation of images of type 2 defects, the values showed no statistical difference, regardless of the device evaluated (p > 0.05). The size of the lesion interferes with the detection capacity in the image. However, the use of portable devices does not impair the diagnosis of IRR, regardless of size and the dental practioners may use different devices/display, under optimal viewing conditions, to detect IRR lesions, without jeopardizing the diagnostic ability.

Evaluation of the efficacy of XP-endo Finisher, Easy Clean, Passive ultrasonic irrigation, and conventional irrigation in the removal of calcium hydroxide in simulated internal root resorption cavities

This study aimed to evaluate the efficacy of 5 irrigation protocols in removing calcium hydroxide in simulated internal root resorption cavities. Eighteen extracted human teeth, upper anterior and uniradicular, were prepared up to size 50. The teeth were divided longitudinally, and internal root resorption cavities were made by acid demineralization using nitric acid. The same sample was submitted to the five irrigation protocols. The cavities and root canals were filled with Ultracal XS (Ultradent, South Jordan, UT, USA) and stored in an incubator at 37ºC for one week. Afterward, the irrigation protocols were carried out: XP-endo Finisher (XPF; FKG, La Chaux-de-Fonds, Switzerland), passive ultrasonic irrigation (PUI), Easy Clean (Bassi/Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) with reciprocating movement (ECR), Easy Clean with continuous rotation (ECC) and conventional irrigation with a syringe (CI). The solutions used, 2.5% NaOCl, and 17% EDTA, were warmed. The total volume of irrigant used for each sample was 20 mL (10 mL of 2.5% NaOCl, 5 mL of 17% EDTA and 5 mL of distilled water). The amount of calcium hydroxide remaining in the internal resorption after irrigation was assessed using scores. The data were analyzed using the Pearson and Kruskal-Wallis (Dunn) tests. Significantly more calcium hydroxide was removed in the XPF group than all other sample groups (P &lt; 0.0001). XPF was superior to the other methods tested to remove calcium hydroxide in teeth with simulated internal resorptions.

Efficacy of Passive Ultrasonic Activation in Removing Calcium Hydroxide from Simulated Internal Resorption Cavities at Different Root Regions.

The aim of this study was to evaluate the effect of passive ultrasonic activation on calcium hydroxide removal from simulated internal root resorption (IRR) cavities at different root levels. Sixty mandibular canines were prepared and divided into 3 groups to create IRR cavities at apical, middle, coronal root levels. The cavities filled with calcium hydroxide (CH). Specimens were divided into two subgroups according to the technique used for CH removal: Passive ultrasonic activation (PUA), Classic syringe irrigation (CSI). The cavities were photographed with a stereomicroscope, and percentage of remaining CH was measured using digital image analysis software (Image J). Statistical analysis was performed with two-way ANOVA and post-hoc Duncan tests. PUA removed significantly more CH at apical and middle levels. (p < 0.05) There was no significant difference between PUA and CSI at coronal level. (p > 0.05) In PUA group, the amount of residual CH was the highest at coronal level. (p < 0.05) In CSI group, the amount of residual CH was the highest at apical level. (p < 0.05). None of the tested technique was able to completely remove CH from the simulated IRR cavities. CH was removed better with PUA than CSI at middle and apical root levels. For both techniques, the best results were obtained at middle root level.

Efficiency of calcium hydroxide removal techniques from simulated internal resorptions - in vitro study

Introduction/Objective. Calcium hydroxide (CH) is the medicament of choice in endodontic treatment of internal root resorptions. The aim of the study was to compare the effectiveness of three different techniques for CH removal from simulated internal root resorptions. Methods. Twenty-nine extracted single-root teeth were prepared using NiTi rotary files of BioRaCe system (40/.04) following irrigation. A round diamond drill was used in the making of a symmetrical standardized internal resorptions 6 mm from the apex. Three techniques for CH removal from internal resorptions were tested: modified conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI), XP-endo Finisher (XP). Resorptive cavities and apical thirds were observed under a stereomicroscope (?45) and scored (from 1 to 5), while representative samples were analysed by a scanning electron microscope. Obtained results were statistically processed by Kruskal?Wallis and Mann?Whitney U-test (p &lt; 0.05). Results. The most efficient system was PUI, with 66.7% of samples rated 1 and 33.3% rated 2. The next one was XP, and the least efficient was CSI, with 33.3% of samples rated 1 (resorptive defect without medicament). There was a statistically significant difference between the PUI and CSI systems (p &lt; 0.05), while there was no difference between the PUI and XP systems. Conclusion. No system completely removed the CH from the simulated internal root resorption cavities. PUI was the most effective system for removing CH. The combination of techniques provides better performance in removing CH paste residues from the canal walls

Influence of adjacent teeth restored with metal posts in the detection of simulated internal root resorption using CBCT.

To assess the influence of artefacts generated by metal posts on the detection of simulated internal root resorption (IRR) in adjacent teeth using cone-beam computed tomography (CBCT) and to verify the impact of metal artefact reduction (MAR) on these cases. CBCT images of 14 premolar teeth were acquired before and after IRR simulation using chemical and mechanical procedures, in an OP300 Maxio unit, with and without MAR. Each tooth was placed in the socket of a human mandible and scanned under three different conditions: (i) without adjacent teeth - control group; (ii) distal adjacent tooth restored with metal post; and (iii) with both adjacent teeth restored with metal post. Five oral radiologists scored the IRR detection using a 5-point scale. Diagnostic values were obtained for the tested groups and compared using two-way analysis of variance (α=0.05). The presence of a single adjacent tooth restored with metal post did not significantly influence the diagnostic values for IRR detection (P>0.05). The presence of both adjacent teeth with metal posts, without MAR application, was associated with a significantly lower area under the ROC curve (Az) compared to the control (P=0.0182). In this case, the application of MAR increased Az, leading to nonsignificant differences from the control group and the group with one adjacent restored tooth (P>0.05). Sensitivity decreased significantly when two adjacent restored teeth were present, regardless of MAR application (P=0.0379). Specificity was not affected by the conditions tested (P>0.05). CBCT detection of IRR was impaired by artefacts only when both adjacent teeth restored with metal posts were present. In such cases, activation of MAR improved the performance on this diagnostic task.

A micro-computed tomography evaluation of voids using calcium silicate-based materials in teeth with simulated internal root resorption

ObjectivesThe obturation quality of MTA, Biodentine, Total Fill BC root canal sealer (RCS), and warm gutta-percha (WGP) in teeth with simulated internal root resorption (IRR) was evaluated by using micro-computed tomography.Materials and MethodsStandardized IRR cavities were created using 40 extracted maxillary central incisor teeth and randomly assigned into 4 groups (n = 10). IRR cavities were filled with MTA, Biodentine, Total Fill BC RCS (bulk-fill form) and WGP + Total Fill BC RCS. Percentage of voids between resorptive cavity walls and obturation material (external void), and inside the filling materials (internal voids) were measured.ResultsTotal Fill BC sealer in the bulk-fill form presented significantly highest values of external and internal void percentages (p < 0.05). Biodentine showed a significantly lowest external void percentage (p < 0.05). WGP + Total Fill BC RCS presented significantly lower values of internal void percentages than all groups (p < 0.05), except Biodentine (p > 0.05).ConclusionNone of the filling materials were created void-free obturation in resorption cavities. Biodentine may favor its application in teeth with IRR over Angelus MTA and bulk-fill form of Total Fill BC.

Bond strength of cemented fiber posts to teeth with simulated internal root resorption.

BackgroundTeeth with internal root resorption (IRR) have guarded prognosis, considering that IRR defect could influence on the post bond strength. The aim of this study was to evaluate the bond strength and the bond interface between different glass fiber-reinforced posts (FRP) after cementation in teeth with simulated internal root resorption (IRR). Material and MethodsForty-five (45) human premolar roots with simulated IRR were embedded in acrylic resin blocks and cross-sectioned into two segments, enabling them to be re-approximated by screws. Intracanal medication was inserted for 15-days, removed by passive ultrasonic irrigation (PUI) and examined by stereomicroscopy. The push-out bond strength of two fiber reinforced composite posts (Rebilda Post - RP) and Rebilda Post GT – GT, (VOCO) were evaluated at the cervical and IRR regions (n = 20). And, the bonded interface between resin cement and root dentine was analysed by scanning electron microscopy (SEM). Results62.5% of IRR were not completely cleaned by PUI. Bond strength values at the cervical region (9.8 and 14.6 MPa) were higher than the IRR region (6.3 and 4.2 MPa). Micrographies showed bubbles in the cement and spaces in the bonded interface. ConclusionsRP post showed better bond strength at the cervical region while GT had better bond strength at the IRR region. Key words:Endodontics, root canal filling materials, root resorption, X-Ray microtomography.

Effectiveness of five instruments when removing calcium hydroxide paste from simulated internal root resorption cavities in extracted maxillary central incisors.

To evaluate the effectiveness of five instruments used for irrigant agitation during the removal of calcium hydroxide [Ca(OH)2 ] paste in simulated internal root resorption (IRR) cavities created in extracted maxillary central incisors. Seventy maxillary central incisors with a single canal were selected. The canals were accessed and instrumented with Reciproc R50, then the roots were split in the bucco-lingual direction and the halves separated. Simulated IRR cavities were created, in both halves of the roots, 5mm from the apex with a spherical bur. The specimens were reconstructed with cyanoacrylate glue and allocated into seven groups: negative control - no treatment; positive control - filled with Ca(OH)2 without performing any irrigation protocol; the other groups were divided according to the instrument used for irrigant agitation, namely: Ultrasonic, EndoActivator® , EDDY® , XP-endo® Finisher and XP-endo® Shaper. The specimens were cleaved and analysed using optical microscopy and scanning electron microscopy, to compare the Ca(OH)2 remnants between them. Then, theIRR cavities created by the burs were cleaned and subjected to a protocol of demineralization with 20% nitric acid, the roots reconstructed, and the irrigant agitation methods, as well as the microscopic analysis was repeated. Analysis of the images of Ca(OH)2 remaining in the simulated IRR cavities after irrigation was performed by two calibrated examiners based on a previously established scoring system. The data were statistically compared by Kruskal-Wallis test, Mann-Whitney U-test and Wilcoxon tests, with the significance level set at 5%. There was a significant difference in the effectiveness of the instruments in relation to the cavity creation method (bur vs. bur/acid) and evaluation method (optical microscopy and scanning electron microscopy) (P<0.05). The XP-endo® Finisher and EDDY® groups were associated with significantly more effective removal of Ca(OH)2 when the IRR cavities were created using the acid protocol and analysed by scanning electron microscopy. None of the instruments tested were able to completely remove the Ca(OH)2 pastefrom the simulated IRR cavities; however, the EDDY® and XP-endo® Finisher removed more Ca(OH)2 in the bur/acid cavity creation method analysed by scanning electron microscopy.

Efficacy of Combined Use of XP-endo shaper and XP-endo Finisher in Cleaning Simulated Internal Root Resorption Defects: An In-Vitro Comparative Study

Aim: Evaluate the efficacy of the combined use of XP shaper and finisher in cleaning simulated internal root resorption defects in comparison to the conventional passive ultrasonic irrigation using stereomicroscope.Materials and methods: The root canals of 90 freshly extracted human mandibular premolars were prepared using Protaper up to F4 and the teeth were split longitudinally and semicircular cavities (simulated internal root resorption cavities) were prepared in the canal wall on each half of the roots, then randomly assigned into two experimental groups (n=40) according to the cleaning technique groups (A) cleaned using passive ultrasonic irrigation , group (B) cleaned using XP-endo shaper followed by XP-endo finisher , five specimens were assigned to serve as negative control and five more were assigned to serve as positive control. Colored gelatin material (CGM) was prepared and applied into the semicircular cavities except for the negative control which did not receive (CGM). The root halves were reassembled creating a circular simulated resorption cavity within the root canal. Specimens were cleaned according to the group they were assigned to except for the positive control which did not receive any further treatment. All the specimens were disassembled and the residual CGM was examined under a stereomicroscope at 10x magnification and calculated as percentage of residual CGM to total area of the IRR cavity by using image analysis software and the data were statistically analyzed with one- way ANOVA test and significance level was set at P> 0.05.Results: None of the tested methods could completely remove the CGM from the simulated IRR cavities. Group B showed lower mean percentage of residual CGM than did group A (P> 0.041).Concussion: within the limitations of this study XP-endo shaper followed by XP-endo finisher was more effective in cleaning inaccessible internal root resorption defects than PUI.

Effect of brightness and contrast variation for detectability of root resorption lesions in digital intraoral radiographs.

To evaluate the performance of periapical radiography assessed under different radiographic brightness and contrast variations in the detection of simulated internal (IRR) and external (ERR) root resorption lesions. Additionally, observers' preferences related to image quality for these diagnostic tasks were evaluated. Thirty single-root teeth were divided into two groups (n = 15): IRR, in which lesions were simulated using mechanical and biochemical processes; and ERR, in which cavities standardized with drills of different sizes were performed on the root surfaces. Digital radiographs were obtained and subsequently adjusted in 4 additional combinations, resulting in 5 brightness/contrast variations (V1-V5). Five radiologists evaluated the radiographs. The observers' preference on the image quality was also recorded. For both conditions, there were no differences in the accuracy and specificity between the five brightness/contrast variations (p > 0.05), but the sensitivity for ERR was significantly lower in V4 (+ 15% brightness/-15% contrast) in the large size (p < 0.05). The observers classified V2 (- 15% brightness/+15% contrast) as the "best" image quality for IRR and ERR evaluation. For IRR and ERR lesions, brightness and contrast variation does not affect the diagnostic performance of digital intraoral radiography within the tested range. The observers prefer images with a reasonable decrease in brightness and increase in contrast. Brightness and contrast enhancement tools are commonly applied in digital radiographic assessment. The use of these tools for detection of root resorptions can be applied according to the observer preference without influence on diagnostic accuracy.

The effectiveness of various irrigation protocols on organic tissue removal from simulated internal resorption defects.

To evaluate the effectiveness of NaOCl, NaOCl-EDTA and NaOCl+HEBP activated by ultrasonics and XP-endo Finisher on organic tissue removal from simulated internal root resorption cavities. The root canals of 144 single-rooted teeth were instrumented. The teeth were split longitudinally, and semicircular cavities were prepared in the canal walls on each half of the roots. Samples obtained from ground bovine muscle tissue were weighed and adapted into the semicircular cavities. The root fragments were reassembled and cemented to create a circular simulated resorption cavity within the canal. Teeth were divided into twelve groups (n=12) according to the irrigation protocols: group 1: NaOCl, no activation; group 2: NaOCl, passive ultrasonic irrigation (PUI); group 3: NaOCl, XP-endo Finisher; group 4: NaOCl-EDTA, no activation; group 5: NaOCl-EDTA, PUI; group 6: NaOCl-EDTA, XP-endo Finisher; group 7: NaOCl+HEBP, no activation; group 8: NaOCl+HEBP, PUI; group 9: NaOCl+HEBP, XP-endo Finisher; group 10: distilled water, no activation; group 11: distilled water, PUI; and group 12: distilled water, XP-endo Finisher. The teeth were disassembled, and the tissue remaining inside the resorption cavities were weighed. The data were analysed statistically using two-way anova and Fisher's LSD tests with a significance level of 0.05. The use of XP-endo Finisher with the experimental solutions resulted in the greatest tissue weight loss compared to the other activation protocols (P<0.001). There was no significant difference between NaOCl and NaOCl+HEBP in terms of tissue removal. The use of a NaOCl+HEBP mixture activated with XP-endo Finisher was an effective irrigation regimen for removing simulated organic tissues from artificial internal root resorption cavities in the straight root canals of single-rooted teeth.

Diagnostic accuracy of phosphor plate systems and conventional radiography in the detection of simulated internal root resorption

Objective: To evaluate the performance of conventional radiography and photostimulable phosphor (PSP) plate in the detection of simulated internal root resorption (IRR) lesions in early stages.Materials and methods: Twenty single-rooted teeth were X-rayed before and after having a simulated IRR early lesion. Three imaging systems were used: Kodak InSight dental film and two PSPs digital systems, Digora Optime and VistaScan. The digital images were displayed on a 20.1″ LCD monitor using the native software of each system, and the conventional radiographs were evaluated on a masked light box. Two radiologists were asked to indicate the presence or absence of IRR and, after two weeks, all images were re-evaluated. Cohen’s kappa coefficient was calculated to assess intra- and interobserver agreement. The three imaging systems were compared using the Kruskal–Wallis test.Results: For interexaminer agreement, overall kappa values were 0.70, 0.65 and 0.70 for conventional film, Digora Optima and VistaScan, respectively. Both the conventional and digital radiography presented low sensitivity, specificity, accuracy, positive and negative predictive values with no significant difference between imaging systems (p = .0725).Conclusions: The performance of conventional and PSP was similar in the detection of simulated IRR lesions in early stages with low accuracy.

A novel model for testing the efficiency of removal of calcium hydroxide from complex root canal anatomies.

The purpose of this study was to evaluate the efficacy of several irrigation protocols in the removal of calcium hydroxide [Ca(OH)2 ] from simulated internal root resorption cavities in a complex root canal anatomy model. The 20° to 35° curved mesiobuccal roots of 94 maxillary molars were sectioned longitudinally; internal resorption cavities were prepared in the apical third of the canal walls. Calcium hydroxide was placed into the cavities and the root halves reassembled. Four teeth were used as controls, and 90 teeth were randomly divided into six experimental groups (n = 15), according to the irrigation protocols used: syringe irrigation; H2 O2 (HP); Navitip FX; Vibringe-syringe; Vibringe-NaviTip FX; ultrasonically activated irrigation (UAI) using an ultrasonic K-file. In the HP group, 2.5% NaOCl and 3% H2 O2 were used, while 2.5% NaOCl and 17% EDTA were used in the remaining groups. Stereomicroscope images and radiographs were used to measure the remaining Ca(OH)2 . The model proved to be suitable for simulating complex anatomy. Positive correlation was found between stereomicroscope and radiographic analyses (P < 0.05). UAI removed significantly more Ca(OH)2 than the other experimental groups (P < 0.05). The HP group was the least efficient protocol (P < 0.05). It would appear that a reliable model has been developed that simulates complex root canal anatomy. Irrigant activation protocols enhanced Ca(OH)2 removal.

CBCT-based volume of simulated root resorption - influence of FOV and voxel size.

To examine the influence of the field of view (FOV) and voxel size on the measurement of the volume of simulated internal root resorption (IRR) lesions through cone-beam computed tomography (CBCT). Eleven single-rooted teeth with IRR simulated by acid demineralization were studied. CBCT images were acquired using large FOV (voxel sizes of 0.200, 0.250 and 0.300 mm) and limited FOV (voxel sizes of 0.076, 0.100 and 0.200 mm). The IRR volumes were calculated using the Dolphin(®) software. Volumetric measurements were validated using IRR silicone putty casts. The analysis of variance (anova) for randomized block design complemented with the Tukey's test was employed. IRR volumes obtained using voxel sizes of 0.200 and 0.250 mm were similar (P > 0.05). However, both these values were significantly different from that obtained using the 0.300-mm voxel (P < 0.05). There was no significant difference between IRR volumes measured through voxel sizes of 0.076 and 0.100 mm (P > 0.05), but both differed significantly from that obtained through the 0.200-mm voxel (P < 0.05). There was no significant difference between the volumetric measurements of the 0.200-mm voxel images of the restricted and large FOV protocols. The mean volumes of the silicone casts were smaller than those calculated using a 0.200-mm voxel, but were similar to those obtained using voxel sizes of 0.076 and 0.300 mm. Despite the FOV protocol, voxel size can influence measurement of simulated IRR volumes. The importance of standardization of CBCT image acquisition protocols is emphasized, especially during follow-up of an IRR lesion, to prevent misinterpretation of its extent, which can create a bias in clinical decisions.

Efficacy of different irrigation techniques in the removal of calcium hydroxide from a simulated internal root resorption cavity

To evaluate the efficacy of six irrigation techniques to remove calcium hydroxide (CH) from a simulated internal root resorption cavity. The root canals of 100 single-rooted teeth were prepared using the ProTaper system to size F5. The roots were split longitudinally, and standardized simulated internal root resorption cavities were prepared in the two root halves. The root halves were reassembled, and CH was placed into the root canals, with the exception of five teeth that served as the negative control group. Another five teeth (the positive control group) were not subjected to the CH removal procedure. Ninety teeth were randomly divided into six experimental groups (n=15), according to the final irrigation techniques used: conventional syringe irrigation (CSI), CanalBrush (CB), passive ultrasonic irrigation (PUI), self-adjusting file (SAF) system, EndoActivator (EA), and apical negative pressure irrigation (EndoVac system). Five millilitres of 3% NaOCl and 17% EDTA were used in all experimental groups during the CH removal procedure. The amount of remaining CH was evaluated under a stereomicroscope at 20×magnification, using a 4-grade scoring system. The data were statistically compared using the Kruskal-Wallis and Mann-Whitney U-tests (P<0.05). Remnants of CH in simulated internal root resorption cavities were found in all experimental groups. SAF and PUI were superior to the other groups (P<0.05); however, there was no significant difference between the SAF and PUI (P>0.05). There were also no significant differences between the CSI, CB, EA and EndoVac groups (P>0.05). None of the irrigation techniques was able to completely remove CH from a simulated internal root resorption cavity.