Cold Lateral Compaction Research Articles

Healing of Periapical Lesion in Teeth Obturated with Different Techniques and Lengths (Radiographic Assessment)

Aim: The purpose of this study was to assess healing of periapical lesion in either symptomatic or asymptomatic cases after obturation with different obturation techniques: cold lateral compaction and single cone obturation techniques at different apical extensions; 1 mm &2mm. Materials and Methods: A total of eighty patients were divided into two main groups; symptomatic or asymptomatic (n=40) then each group was subdivided into two subgroups (n=20) according to the obturation technique; subgroup a: Cold lateral compaction technique and subgroup b: single cone obturation technique. Further, each subgroup was divided into two divisions (n=10) depending on whether the apical extent; 1 or 2 mm from radiographic apex. All cases were prepared and obturated. CBCT scans were taken preoperatively, at 3, 6, and nine months and volume of the lesion was calculated to determine the treatment outcome. Data were then gathered, tabulated and statistically analyzed. Results: At 1mm, no significant difference between mean % changes in lesion volume after using lateral compaction or single cone techniques either asymptomatic or symptomatic along the evaluation periods while at 2mm lateral compaction technique showed higher mean % decrease in lesion volume than single cone technique after 3, 6 as well as 9 months. In both groups, using lateral compaction technique, no significant difference was recorded at 1 or 2 mm apical extension of filling while in single cone, at 1mm apical extension revealed higher decrease in lesion volume than 2mm Conclusions: Radiographic success rate of the single cone obturation technique was comparable with those of the lateral compaction obturation technique in root canal treatment of teeth with periapical lesions in short term evaluations at 1mm apical extension.

Dentinal Adaptation of Warm Thermoplastic Obturating Material and Cold Thermoplastic Obturating Material: An In vitro Study.

Introduction:The objective of endodontic obturation is to provide a complete seal along the length of the root canal system, thereby ensuring the healing and sustained health of the periradicular tissue. Root canal obturation involves the three-dimensional filling of the entire root canal system and is a critical step in endodontic therapy. Gutta-percha has universally been accepted as the gold standard for root canal filling materials. However, it lacks bonding to the internal tooth structure resulting in the absence of complete seal.Aim:The aim of the present study is to compare the dentinal adaptation of warm thermoplastic obturating material and cold thermoplastic obturating materials.Materials and Methods:Thirty single-rooted, anterior noncarious human teeth extracted for periodontal or orthodontic reasons were used for the study. The samples were stored in distilled water until obturation. The specimens were then randomly divided into three groups of ten specimens each: Control group – Cold lateral condensation with AH Plus, Group I – Endosure with AH Plus®, and Group II – GuttaFlow® 2 with master cone. The obturation for each group was done following manufacturer's instructions. Under On-demand software, the area of voids at the level of 3 mm, 5 mm, and 8 mm from the apex was observed for all the samples. The obtained results were submitted for statistical analysis.Results:The result in the present study showed that Endosure provides a better consistent seal as compared to cold lateral condensation, or GuttaFlow 2 techniques.Conclusion:Mean void value was maximum for GuttaFlow 2 group, followed by cold lateral condensation, Endosure. Though there was a difference in the mean void values, it was not statistically significant except between Endosure and GuttaFlow 2. The result in the present study showed that Endosure provides a better seal as compared to cold lateral compaction, GuttaFlow 2 or Endosure technique.

Postoperative pain after glide path preparation using manual, reciprocating and continuous rotary instruments: a randomized clinical trial.

To compare the incidence, intensity and prediction of postoperative pain after glide path preparation with manual, continuous rotary and a novel reciprocating glide path instrument. The study included 240 patients, who were treated by four specialists according to a planned treatment protocol. Following access cavity preparation and prior to glide path preparation, the subjects were randomly assigned to one of the three groups according to the glide path instrument by choosing a sealed envelope containing the group name: R-Pilot (VDW, Munich, Germany), ProGlider (Dentsply Sirona, Ballaigues, Switzerland) and stainless steel K-files (Dentsply Sirona; n=80). Following glide path preparation, the teeth underwent standardized single visit root canal treatment procedures. The root canals were chemomechanically prepared using the ProTaper Next rotary system (Dentsply Sirona) under copious irrigation with 5.25% NaOCl. Final irrigation was performed with 17% EDTA and distilled water. Root fillings were placed using an epoxy resin sealer and gutta-percha with a cold lateral compaction technique. After coronal restorations were placed, the patients were discharged with a questionnaire about the incidence and intensity of pain at 6, 12, 18, 24, 48 and 72h postoperatively. The data were analysed using chi-square, anova and Tukey tests and logistic regression analysis. The presence of preoperative pain (OR ranged between 3.5 and 14.3) and the glide path preparation techniques (OR between 2.2 and 4.1) were associated with significant effects on the incidence of postoperative pain when comparing manual versus engine-driven glide path preparation (P<0.05). Patients in the R-Pilot (Mean VAS ranged between 1.57-0.21) and ProGlider (1.97-0.28) groups reported significantly less postoperative pain scores than those in the manual group (2.82-1.32; P<0.05). There was no significant difference between R-Pilot and ProGlider groups regarding the postoperative pain scores (P>0.05). Preparation of glide paths with rotating or reciprocating NiTi instruments was associated with less postoperative pain levels and incidence compared to manual glide path preparation with no significant difference between rotating and reciprocating instruments. Preoperative pain was the most significant predictor for the occurrence of postoperative pain.

The Effect of Different Irrigation Agitation Techniques on Postoperative Pain in Mandibular Molar Teeth with Symptomatic Irreversible Pulpitis: A Randomized Clinical Trial

IntroductionThis study compared the effect of several final irrigation agitation techniques (sonic agitation, passive ultrasonic irrigation, and manual dynamic agitation [MDA]) in comparison with needle irrigation on postoperative pain in mandibular molar teeth with symptomatic irreversible pulpitis. MethodsOne hundred sixty-eight patients with a single tooth diagnosed as symptomatic irreversible pulpitis were selected. Teeth were randomly assigned to 4 groups based on the final irrigation methods. In group 1 (needle irrigation), irrigation was conducted without agitation with a side-port needle; in group 2, sonic agitation was used; in group 3, passive ultrasonic irrigation was used; and in group 4, MDA was used. Teeth were then obturated with gutta-percha and a resin-based sealer using the cold lateral compaction technique. The presence of postoperative pain was assessed after 6, 24, 48, and 72 hours and 1 week. ResultsAt the 6- and 24-hour time intervals, group 4 patients reported more intense postoperative pain than those patients in groups 1, 2, and 3 (P < .05). There was no significant difference among the groups at the other time intervals (P > .05), and in all groups the intensity of postoperative pain decreased over time. ConclusionsMDA caused greater postoperative pain after endodontic therapy in mandibular molar teeth with symptomatic irreversible pulpitis compared with the other methods in the first 24 hours.

Root Canal Treatment of a Maxillary Second Molar with Two Palatal Roots: A Case Report

Introduction: Endodontic treatment is done to eliminate the potential sources of infection from the root canal space. Having extensive knowledge of the exact of internal anatomy of root canals is a prerequisite for a successful endodontic treatment. It is abnormal to have a second palatal root in a maxillary second molar; however, accurate diagnosis could provide a suitable treatment. Case Presentation: The current study reports on a 20-year-old female with a maxillary second molar with two palatal roots. Using the cold lateral compaction technique, the canals were filled with gutta-percha and AH26 sealer. Additionally, a detail description of the treatment and its management is provided in this report. Conclusions: On the third month of follow-up, all signs had disappeared and the patient showed no sign of periodontal ligament space widening.

The Effect of Apical Positive and Negative Pressure Irrigation Methods on Postoperative Pain in Mandibular Molar Teeth with Symptomatic Irreversible Pulpitis: A Randomized Clinical Trial

IntroductionThis study compared the effect of conventional needle irrigation (positive pressure) and the EndoVac system (Discus Dental, Culver City, CA) (negative pressure) on postoperative pain in mandibular molar teeth with symptomatic irreversible pulpitis. MethodsOne hundred sixteen patients with symptomatic irreversible pulpitis were selected. Teeth were randomly assigned to 2 groups according to the irrigation methods performed during root canal preparation. In group 1, root canal irrigation was performed using a syringe and a 31-G side-port needle (NaviTip; Ultradent, South Jordan, UT). In group 2, the EndoVac system was used for irrigation. Teeth were then obturated with gutta-percha and a resin-based sealer using the cold lateral compaction technique. The presence of postoperative pain was assessed after 6, 24, 48, and 72 hours and 1 week. ResultsAt 6-, 24-, and 48-hour time intervals, group 1 patients reported more intense postoperative pain than patients in group 2 (P < .05). There was no significant difference between the 2 groups at the other time intervals (P > .05), and in both groups the intensity of postoperative pain decreased over time. ConclusionsApical positive pressure irrigation caused greater postoperative pain after endodontic therapy of mandibular molar teeth with symptomatic irreversible pulpitis compared with the apical negative pressure irrigation system.

Apically extruded debris during the removal of canal filling material from root canals using three techniques.

In the present study, we evaluated the effect of the single-cone technique (SCT), cold lateral compaction (CLC), and wave vertical compaction (WVC) technique performed using two different sealers on the amount of apically extruded debris (AED) produced during the removal of canal filling material. Ninety extracted mandibular premolars were prepared with ProTaper instruments. The teeth were then randomly assigned to six groups (N=15) for root canal filling: (a) group 1, CLC+AH Plus; (b) group 2, SCT+AH Plus; (c) group 3, WVC+AH Plus; (d) group 4, CLC+MTA Fillapex; (e) group 5, SCT+MTA Fillapex; and (f) group 6, WVC+MTA Fillapex. In all groups, the removal of canal filling material was performed with ProTaper retreatment instruments. The mean weight of the AED was assessed with an analytical balance. The amount of AED was lowest in groups 2 and 5 (P<.05), with no difference between these groups (P>.05). Groups 3 and 6 produced the greatest amount of extruded debris (P<.05); there was no difference between these groups (P>.05). Additionally, there was no difference between groups 1 and 4 (P>.05). There was no significant difference among the groups regarding sealer type (P>.05). The canal filling technique used affected the amount of AED produced during the removal of canal filling material, but not sealer type.

Comparison of apical sealability of three obturation techniques (an in vitro study)

The aim of this study was to evaluate the sealing ability and the time required tocomplete obturationof three different obturation techniques.The palatal roots of sixtymaxillary first molar teeth were selectedfor this study. The root canals prepared usingProFile rotary instruments to an apical dimension of size 40 (.06 taper). Thespecimenswere then randomly divided into 3 experimental groups (20 sample of each) and filledwith gutta-percha and sealer byusing either cold lateral compaction, Thermafil, or theEasy &amp; Quick Master system.For the first parameter(Time of obturation), the resultsshowed that Thermafil technique required the least time to complete obturation and itwas significantly lower than other twogroups.The second measurement(Microleakage) showed that the lateral condensation technique leaked apically andsignificantly higher than other test groups, while the Thermafil group exhibited theleast value of apical microleakage.

Comparison of the amount of apically extruded debris produced by four retreatment techniques: an ex vivo study

Objetivo: o objetivo deste estudo foi comparar a quantidade de detritos apicalmente extruídos durante a remoção do material obturador do canal radicular usando instrumentos de retratamento rotativo de níquel-titânio e limas de Hedström. Material e Métodos: sessenta incisivos mandibulares com um único canal foram instrumentados e obturados por compactação lateral fria. Para retratamento, os espécimes foram divididos aleatoriamente em quatro grupos (n = 15): limas de Hedström com ou sem solvente; Sistema D-RaCe e sistema de retratamento Mtwo. Os detritos extrusados ??apicalmente durante a remoção do material de enchimento do canal foram recolhidos em tubos Eppendorf pré-pesados. Os tubos foram então armazenados em uma incubadora a 70 ° C por 5 dias. O peso dos detritos extrudidos a seco foi estabelecido subtraindo o pré-tratamento e o peso pós-tratamento dos tubos Eppendorf para cada grupo. Os pesos médios do material extrudido foram analisados ??por ANOVA de uma via. Resultados: os resultados mostraram que todas as técnicas de retratamento causaram a extrusão apical de detritos, mas não houve diferença estatisticamente significante entre os grupos (p&gt; 0,05). Conclusão: nas condições deste estudo, todas as técnicas de retratamento causaram extrusão de detritos apicais.

3D Micro-CT Analysis of Void and Gap Formation in Curved Root Canals

Objective This study used microcomputed tomography (micro-CT) to compare the volumes of voids and gaps in curved root canals instrumented and filled using various techniques. Methods Twenty extracted mandibular first molars with two curved mesial root canals were used. Root canals were instrumented using a self-adjusting file (SAF) or Revo-S file system. For standardization, mesiobuccal canals were instrumented with SAF and mesiolingual canals were instrumented with Revo-S in each root. The canals were divided into four experimental groups (n=10 in each). The canals were then filled via cold lateral compaction (CLC) or a thermoplasticized injectable technique (TT) using gutta-percha and AH Plus root canal sealer. The roots were scanned with a micro-CT, and the volumes of the voids and gaps were calculated using three-dimensional (3D) micro-CT images. Data were analyzed using unpaired t- and Kruskal-Wallis tests. A value of P 0.05). Conclusion The SAF and Revo-S rotary file systems yielded comparable results. No statistically significant difference was found between the results of the various instrumentation and filling techniques.

3D Micro-CT Analysis of Void and Gap Formation in Curved Root Canals.

Objective:This study used microcomputed tomography (micro-CT) to compare the volumes of voids and gaps in curved root canals instrumented and filled using various techniques.Methods:Twenty extracted mandibular first molars with two curved mesial root canals were used. Root canals were instrumented using a self-adjusting file (SAF) or Revo-S file system. For standardization, mesiobuccal canals were instrumented with SAF and mesiolingual canals were instrumented with Revo-S in each root. The canals were divided into four experimental groups (n=10 in each). The canals were then filled via cold lateral compaction (CLC) or a thermoplasticized injectable technique (TT) using gutta-percha and AH Plus root canal sealer. The roots were scanned with a micro-CT, and the volumes of the voids and gaps were calculated using three-dimensional (3D) micro-CT images. Data were analyzed using unpaired t- and Kruskal-Wallis tests. A value of P<0.05 was considered significant.Results:None of the tested techniques provided void- or gap-free fillings. Nevertheless, the SAF showed more gap formation than the Revo-S, and TT showed higher gap formation in all experimental groups. These differences, however, were not statistically significant (P>0.05).Conclusion:The SAF and Revo-S rotary file systems yielded comparable results. No statistically significant difference was found between the results of the various instrumentation and filling techniques.

Evaluation of Different Techniques for Filling Simulated C-shaped Canals of 3-dimensional Printed Resin Teeth

IntroductionThe purpose of this study was to compare the ability of different root canal filling methods on the C1 root canal anatomy using 3-dimensional (3D) printer technology. MethodsMandibular molars were scanned with cone-beam computed tomographic (CBCT) imaging. A mandibular molar tooth with a C1 root canal configuration was selected according to images obtained from CBCT technology. The root canals were shaped with ProTaper Universal rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) and hand files. After the root canal shaping procedure, the tooth was scanned with micro–computed tomographic imaging, and 80 replicas of the tooth were produced with a 3D printer. Replicas were assigned into 4 groups (n = 20) and were filled using one of the following techniques: a core carrier system (GuttaCore [GC]; Dentsply Tulsa Dental Specialties, Tulsa, OK), a continuous wave obturation system (Elements Free [CW]; Kerr/SybronEndo, Orange, CA), a cold lateral compaction technique (CLC), or the injectable cold filling method (GuttaFlow Bioseal [GFB]; Coltène/Whaledent AG, Altstatten, Switzerland). All specimens were sectioned horizontally at 2, 4, 6, 8, and 10 mm from the apices of the specimens. The sections were examined at 32× magnification under a stereomicroscope, and the percentage areas of gutta-percha, sealer, and voids were measured. Statistical analysis of data was performed using multivariate analysis of variance and Tukey honestly significant difference tests (P < .05). ResultsThe CW group had the highest mean percentages for void and the least mean percentages for gutta-percha at 2-mm sections (P < .05). A pairwise comparison between the groups showed significantly less void in the CLC and GFB groups and more void in the CW and GC groups at 2 mm (P < .05). In the total area, the CLC and GFB groups showed a significantly lower percentage of gutta-percha and more sealer compared with the other groups (P < .05), and there was no significant difference between the CLC and GFB groups (P > .05). ConclusionsAt the apical part of the canal, the cold lateral compaction and cold injectable filling techniques were more successful compared with the warm gutta-percha filling techniques in C1 root canal configuration.

Effect of Post Space Preparation on Apical Obturation Quality of Teeth Obturated with Different Techniques: A Micro–computed Tomographic Study

IntroductionThe purpose of this study was to evaluate the obturation quality of root canals filled with different techniques and to determine whether post space preparation had an effect on the quality of apical obturation using micro–computed tomographic (micro-CT) imaging. MethodsThe root canals of 30 human mandibular premolar teeth were instrumented, and the specimens were divided into 3 groups according to the obturation technique used: cold lateral compaction (CLC), warm vertical compaction (WVC), or single-cone (SC) techniques. The specimens were stored at 37°C and 100% humidity for 1 week. Then, the coronal root filling material was removed in order to create a post space. Micro-CT scans were performed before and after post space preparation for the volumetric analysis of voids and filling materials. Data were analyzed using repeated-measures analysis of variance and Bonferroni tests. ResultsThe CLC and SC groups showed a significantly greater percentage volume of voids than the WVC group (P < .05), whereas no significant difference was found between the CLC and SC groups before and after post space preparation (P > .05). The post space preparation caused a significant increase in the percentage volume of voids in the CLC and SC groups (P < .05). No significant difference was detected in the percentage volume of voids in the WVC group after post space preparation (P > .05). ConclusionsNo root fillings were void free. The WVC group presented the best obturation quality. The post space preparation negatively influenced the apical integrity of the filling materials in the CLC and SC groups, whereas it had no significant effect in the WVC group.

Evaluation of various filling techniques in distal canals of mandibular molars instrumented with different single-file nickel-titanium systems.

The aim of this study was to evaluate the quality of various filling techniques in distal canals of mandibular molars instrumented with different single-file nickel-titanium (NiTi) systems. A total of 150 distal roots of mandibular molar teeth were randomly assigned into three main groups and instrumented by using Reciproc (VDW, Munich, Germany), WaveOne (Dentsply Tulsa, Tulsa, OK, USA), or One Shape (MicroMega, Besancon, France) NiTi file systems. The roots were then treated using one of five filling techniques: (1) Matched-single-cone, (2) cold lateral compaction with matched gutta-percha (GP) cone, (3) Thermafil filling, (4) System B/Obtura II, and (5) lateral compaction with standardized GP cones. The roots were then sectioned at three levels (coronal, middle, and apical). Photographs were acquired under a stereomicroscope, and the percentage of GP-filled areas (PGFAs), percentage of sealer-filled areas (PSFAs), and voids were measured using the ImageJ software. Comparisons between groups were applied using Student's t-test or one-way ANOVA for normally distributed data. The Mann-Whitney U-test or Kruskal-Wallis test was used when variables were not normally distributed. Canals filled with the System B/Obtura showed the highest PGFA and lowest PSFA, whereas those filled with matched-single-cone showed the highest PSFA and lowest PGFA (P < 0.05). The cold lateral compaction with matched GP cone group, lateral compaction group, and Thermafil filling group showed no statistically significant differences in PSFA and PGFA (P > 0.05). System B/Obtura technique appears to be the best technique to properly fill root canals, whereas the matched-single-cone technique in oval-shaped distal canals of mandibular molars was inadequate.

Volumetric analysis of root filling with cold lateral compaction, Obtura II, Thermafil, and Calamus using spiral computerized tomography: An In vitro Study.

The aim of the present study is volumetric analysis of root canal filling with cold lateral compaction, Obtura II, Thermafil, and Calamus using spiral computerized tomography (SCT). Root canals of eighty mandibular premolars were instrumented using rotary ProTaper, and the volume of the canal space was measured using spiral computerized tomography (SCT). The teeth were divided into four groups of twenty teeth each, and root canals filled by lateral compaction technique, Thermafil carriers, Obtura II, and Calamus techniques, respectively. AH Plus was used as a sealer with all techniques. The filled volume in each canal was measured using SCT, and the percentage of obturated volume (POV) was calculated. The data were statistically analyzed using ANOVA, Kruskal-Wallis test, and Mann-Whitney U-test. The four groups were comparable in canal volume. The overall POV was 78.11%, 85.72%, 82.50%, and 87.89% for lateral compaction, Thermafil, Obtura II, and Calamus, respectively (P Conclusion: The greatest POV was obtained with Calamus and Thermafil. Voids were seen in all root fillings.

Evaluation of the Sealing Ability of Three Obturation Techniques Using a Glucose Leakage Test.

The aim of this study was to evaluate the sealing ability of three different canal filling techniques. Sixty-four roots of extracted human maxillary anterior teeth were prepared using ProTaper® rotary instruments. The specimens were then randomly divided into 3 experimental groups (n = 16) and 2 control groups (n = 8). The root canals were filled using cold lateral compaction (CLC group), continuous wave condensation technique using the Elements Obturation Unit® (EOU group), and ProTaper obturators (PT group). For the negative control group, 8 roots were filled using lateral compaction as in the CLC group, and the teeth were covered twice with a layer of nail varnish (NCG group). Another 8 roots were filled using lateral compaction, but without sealer, and these were used as the positive control (PCG group). A glucose leakage model was used for quantitative evaluation of microleakage for 24 hours and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 weeks. No significant difference in the cumulative amount of leakage was found between the three experimental groups at all observation times. The lateral condensation of cold gutta-percha can guarantee a similar seal of canal fillings as can be achieved by using thermal methods, in the round canals.

Factors associated with postobturation pain following single-visit nonsurgical root canal treatment: A systematic review.

Reducing the pain after root canal therapy is a key aspect in endodontic practice. The present systematic review aimed to identify the factors that influence postobturation pain (POP) in patients receiving single-visit nonsurgical root canal treatment. A literature search was performed manually and in Pubmed (Medline) database to identify relevant articles. A data extraction form was constructed and data were collected from the identified articles. In total, 24 articles were identified for the systematic review, and factors associated with POP were tabulated. Specific preoperative factors (old age, sex, molar teeth, mandibular teeth, presence of preoperative pain, and absence of periapical radiolucency) and procedures (administration of prophylactic drug, bupivicaine anesthetic agent, radiograph or apex locator working length determination methods, instrumentation, irrigating system, laser, cold lateral compaction obturation technique, reducing the occlusion, and postoperative drugs) were associated with POP.

Comparative evaluation of fracture resistance of root canals obturated with four different obturating systems

Aim and Objectives:The aim of this study is to evaluate and compare the fracture resistance of root canals obturated with four different obturating systems in endodontically treated teeth.Materials and Methods:One hundred and twenty single-rooted teeth were selected and decoronated at cementoenamel junction. Instrumentation of teeth (except control group) was done with Mtwo rotary files up to size 25/0.06 using a step-back technique. All teeth were divided into four experimental groups (n = 25) and two control groups (n = 10). In Group I (negative control), teeth were neither instrumented nor obturated, in Group II (positive control), instrumentation was done, but no obturation was performed, in Group III, obturation was done with cold lateral compaction technique, in Group IV, obturation was done with cold free-flow compaction technique, in Group V, obturation was done with warm vertical compaction technique, and in Group VI, obturation was done with injection-molded thermoplasticized technique. All prepared teeth were embedded in an acrylic resin block, and their fracture strength was measured using Universal Testing Machine. Statistical data were analyzed using one-way analysis of variance and Tukey's honestly significant difference test.Results:Negative control Group I showed highest fracture resistance and positive control Group II had lowest fracture resistance. Among experimental groups, cold free-flow compaction technique with GuttaFlow2 (Group IV) showed higher fracture resistance as compared to the Group III, Group V, and Group VI.Conclusion:GuttaFlow2 has the potential to strengthen the endodontically treated roots to a level that is similar to that of intact teeth.

Comparison of efficiency of manual(H-Files) and two rotary niti retreatment systems(Mtwo R files and HyFlex NT files) in removing Gutta-percha from root canals obturated with two different sealers by using stereomicroscope - An in vitro study

Objectives: The aim of this study was to compare manual and two nickel titanium (NiTi) rotary retreatment systems in removing gutta-percha obturated with two different sealers. Materials and Methods: Sixty extracted, human, single-rooted mandibular premolars were selected. Endodontic treatment was performed using ProTaper Universal NiTi rotary instruments. Half of the samples were obturated with Tubliseal and remaining half were obtutared with AH Plus sealer with cold lateral compaction method. Subsequently, twenty teeth were retreated with manual retreatment system, and each twenty teeth was retreated with two different rotary retreatment systems. The roots were then grooved longitudinally, and both root halves were subjected to assessment under stereomicroscope, and images were taken with a digital camera. These images were evaluated for residual obturating material using AutoCAD software. Analysis of variance test and Bonferroni multiple comparison test were used for statistical analysis. Results and Conclusion: Results of the present study showed that no system was able to completely remove all debris from the root canals. The minimum amount of debris was seen in the group obturated using Tubliseal sealer and retreated with Hyflex NT retreatment system followed by Mtwo retreatment system and finally the manual retreatment protocol. Regarding the time taken, Mtwo retreatment files took least time to remove the obturating material in all sealer groups.

Micro-CT assessment of dentinal micro-cracks after root canal filling procedures.

To evaluate the frequency of dentinal micro-cracks after root canal filling procedures with GuttaCore (GC), cold lateral compaction (CLC) and warm vertical compaction (WVC) techniques in mandibular molars using micro-computed tomographic analysis. Thirty mesial roots of mandibular molars, with a type II Vertucci's canal configuration, were prepared to working length with a Reciproc R40 instrument and randomly assigned to one of the three experimental groups (n=10), according to the technique used for root filling: GC, CLC or WVC. The GC group was filled with a size 40 GC obturator, whilst CLC and WVC groups used conventional gutta-percha cones. AH Plus sealer was used in all groups. The specimens were scanned at an isotropic resolution of 14.25μm before and after root canal preparation and after root filling. Then, all pre- and postoperative cross-sectional images of the roots (n=41660) were screened to identify the presence of dentinal defects. Overall, 30.75% (n=12810) of the pre- + post-filling images displayed dentinal defects. In the GC, CLC and WVC groups, dentinal micro-cracks were observed in 18.68% (n=2510), 15.99% (n=2389) and 11.34% (n=1506) of the cross-sectional images, respectively. All micro-cracks identified in the post-filling scans were also observed in the corresponding post-preparation images. Root fillings in all techniques did not induce the development of new dentinal micro-cracks.