Obturation Material Research Articles

Microbiological status of root canal after unsuccessful endodontic treatment

Summary Introduction The main objective of endodontic treatment is to eliminate infection from root canal and prevent reinfection by three-dimensional hermetic obturation of the canal system. Endodontic failure can occur due to inability of complete control and elimination of infection from the root canal. The aim of this study is to investigate, by PCR technique, microbiological status of previously endodontically unsuccessfully treated teeth immediately after the removal of obturation material. Material and Methods The analysis included 30 teeth indicated for endodontic retreatment. After removing previous root canal filling material, the bacteriological sample was taken by sterile instrument (# 15) and paper points. Standard PCR technique was used to analyze the incidence of E.faecalis, P.micros, P.intermedia, P. endodontalis and A.actinomycetemcomitans. Results Positive bacteriological findings were registered in 80% of cases, while bacteria were not identified in 20% of all samples (all taken from the root canals without significant changes in periapical tissue). From 24 canals with identified bacteria, 17 had affected apical periodontium. The most dominant microbe in root canals with positive bacteriological finding was E.faecalis (83.3% of the canals) and P.intermedia (75%). In case of teeth with chronic periapical changes, the most common was E. faecalis (94%) and P.intermedia (82.3%). Conclusion The presence of periapical lesions significantly affects microbiological status of endodontically treated teeth. The presence of bacteria was confirmed in most teeth with periapical lesions, while the most frequently identified bacteria were E. faecalis, P.intermedia and P.micros.

Long-term pain caused by obturation material pushed beyond the apex - a case report

Long-term pain caused by obturation material pushed beyond the apex - a case report

Effect of Resin-based and Bioceramic Root Canal Sealers on Postoperative Pain: A Split-mouth Randomized Controlled Trial

IntroductionThe aim of this study was to compare the effect of resin-based and bioceramic root canal sealers on the occurrence and intensity of postoperative pain in patients with asymptomatic apical periodontitis (AAP). MethodsPatients presenting with AAP in previously endodontically treated teeth were included in this split-mouth blinded randomized controlled trial. For each patient, 2 single-rooted teeth were retreated and obturated using the warm vertical condensation technique and different obturation materials (ie, a gutta-percha point with resin-based sealer and a bioceramic-coated gutta-percha point with bioceramic sealer). Treatment of 1 root canal was performed in a single visit. Postoperative pain was recorded by a visual analog scale (VAS) at 24 hours, 48 hours, 72 hours, and 7 days after obturation. ResultsOf the 61 included patients, 57 individuals presenting 114 teeth completed the study. There was no statistically significant difference between the tested root canal sealers regarding postoperative pain at any time points assessed (P > .05). In total, 20 (35%) patients perceived pain. Only 1 patient reported severe pain. VAS scores of 80 and 70 were reported in the AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) and Total Fill (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) groups, respectively. Pain intensity decreased about 2-fold in both groups at 48 hours after treatment. There were no reports of pain since 72 hours after obturation. The odds ratio for pain occurrence in the lower premolars was 7.2 (95% confidence interval, 1.708–30.352) compared with the upper front teeth. ConclusionsAH Plus and Total Fill perform similarly in terms of the occurrence and intensity of postoperative pain in teeth with AAP with no material extrusion beyond the apex.

Regenerative endodontic therapy for managing immature non-vital teeth: a national survey of UK paediatric dental specialists and trainees.

Background Several guidelines have been published advocating the use of regenerative endodontic therapy (RET) in managing non-vital immature permanent teeth. It is unclear, however, how many UK paediatric dental specialists routinely use this technique and their opinion of its outcomes, and barriers to its use.Aim To assess the knowledge, experience and the opinion of UK based paediatric dental specialists/trainees (UKPDS/T) and practitioners working in the capacity of paediatric dental specialists on the use of RET.Design A cross-sectional study using a 22-item questionnaire was developed using the Bristol Online Survey tool and circulated electronically to members of the British Society of Paediatric Dentistry between August and November 2016.Results Ninety-eight UKPDS/T completed the survey. A quarter of respondents (N = 24, 24.5%) reported using RET. Reasons cited for not using RET included lack of: training (N = 48, 45%), materials (N = 28, 26%), evidence (N = 17, 16%) and suitable cases (N = 6, 6%). Different protocols in terms of disinfection, medicaments, scaffolds, and obturation material were identified.Conclusions This survey highlights a low uptake of RET by current UKPDS and trainees with several barriers identified. Deviations from the current RET guidelines were identified. Recommendations addressing the use of RET in light of the findings of this survey were made.

Natural products in endodontics.

Herbal remedies are used throughout the world, either in earlier or in recent times. The number of studies on this alternative therapeutic system increased in the last decades. In this paper, the relevant literature on the use of natural products in root canal therapy is revised from a MEDLINE database search. The uses of medicinal plants in endodontics include cleaning and disinfection of root canals, intracanal medicaments between appointments, sealer cements, and for removal of obturation material. Other studies showed the effect of natural products in pulpal and dentin repair. Their use is anecdotal, and their effectiveness showed to be variable and is always compared to the chemical standards currently being used. Alkaloids, coumarins, saponins, and flavonoids are aromatic substances that are produced by plants and evaluated for their therapeutic potential. Further investigation into benefits of natural products is warranted.

Estimation of inferior alveolar nerve proximitytothe root api-ces : A CBVI analysis

A sound knowledge of the relative three dimensional (3D) approximations to the inferior alveolar nerve (IAN) to the root apices of the mandibular premolars and molars and their significance to gender and age is imperative for any dental procedure. Utilization of Cone Beam Computed Tomography (CBCT) has facilitated increased accuracy, higher resolution, and scan time and dose reduction. Literature reveals that various procedures in endodontics and oral surgery may lead to IAN injury, a rare but serious treatment complication. It can result from over instrumentation, periapical surgery and over filling by root canal obturation materials. Surgical endodontic procedures require a thorough knowledge of anatomic structures that might be traumatized. What better view than CBCT, where it gives a thorough knowledge about the 3D position of the IAN, allowing 3D reconstruction in true 1:1 anatomic representation. Majority of IAN injury cases reported were in relation to the mandibular second molars hence before undertaking procedures with potential damage to the IAN, it is essential to know the location of the IAN with respect to the surrounding structures to avoid injury or harm. A study was undertaken with an aim to assess the distance between the apical tips of the mesial roots of the first, second molars and second premolars to the superior border of the IAN. The findings of which could be used to prevent injuries to the inferior alveolar nerve.

The effect of dowel space preparation on the apical seal of Resilon & Gutta-percha obturation materials. (An in vitro comparative study

Aim: The aim of this in vitro study was to compare the effect of immediate versus delayed dowel space preparation using peeso reamers on the apical seal of roots filled by Gutta-percha with two types of resin based-sealers (AH26 and AH Plus) and by Epiphany obturation system.Methodology: Sixty freshly extracted human teeth with single and straight canals were used in this study. The roots were instrumented using the step-back technique, instrumentation was accomplished by using the Gates-Glidden drills with copious irrigation of 2.5% sodium hypochlorite and 17% solution of aqueous EDTA to remove smear layer. The roots were randomly divided into 3 main groups according to the type of obturation materials using lateral condensation technique (20 teeth for each group):Group A: Gutta-percha + AH26 root canal sealer.Group B: Gutta-percha + AH Plus sealer.Group C: Resilon+ Epiphany sealer+ prime. (Epiphany obturation system)Then each group divided into two subgroups according to the time of dowel space preparation either immediately after obturation or after one week. The external surfaces of all roots were coated by two layers of sticky wax except for the apical 2 mm and were then submerged in 2% methylene blue dye for 3 days at 37ºC. After that, all roots were longitudinally sectioned for linear measurement of dye penetration through the apical foramen using a stereomicroscope. The data obtained were analyzed statistically using ANOVA and Student t-tests.Results: Significantly less apical leakage in roots filled by gutta-percha with AH Plus than those filled by gutta-percha with AH26 and those filled by Epiphany obturation system for delayed dowel space preparation (P< 0.05) and there was a significantly less apical leakage in roots filled by Epiphany obturation system that prepared immediately after obturation than those received delayed preparation (P< 0.05).Conclusion: All the groups had apical leakage what ever the type of obturation material or time of dowel space preparation.

Technique and Management of an Iatrogenic Defect Caused During Retrieval by Treating It as A Canal Extension: A Case Report

Masserann technique is one of the methods suggested for retrieval of separated instruments. However, its application in posterior teeth is risky, difficult, and clinically challenging. This case report illustrates successful application of Masserann technique to retrieve a separated instrument from the middle third of a mesial canal of a mandibular second molar and management of an iatrogenic defect, which was caused during retrieval, by treating it as a canal extension during obturation. This obturation was done with glass ionomer cement based sealer for canal reinforcement. In the absence of other effective techniques, when the separated instrument is tightly lodged in the canal, Masserann technique could be useful for instrument retrieval in posterior teeth. However, its success depends on case selection and clinical skill. Since this technique leads to removal of considerable amount of dentin, use of bonding or adhesive obturation materials could be considered to reinforce and strengthen the root. DOI:10.21276/AOHDR.1897

Comparison of Apical Adaptation Between Several Obturation Methods: An in Vitro Study

Objective: To compare lateral compaction obturation with carrier-based gutta-percha and downpack-backfill. Material and Methods: Ninety tooth with single root canal were prepared with rotary Protaper and divided into 3 groups: Group 1 obturated with lateral heated compaction (LHC), Group 2 with carrier-based gutta-percha (CP) and Group 3 with downpack-backfill (DB). The apical one-third adaptation was determined by examining the dye penetration between obturation material and root canal wall on the horizontal cut samples. The data received was analyzed using SPSS 17 software. Chi-square statistical test was done with level of significance (α) of 0.05. Results: The DB group had the highest amount of score of 0, followed by CP group and LHC group. The DB group had 28 samples (93.3%) with score of 0, which was the largest compared to the CP and LHC group. All groups had some score 2, and score 3 and 4 were only examined in the LHC group Adaptation of the apical one-third on DB group had the best result, followed by CP and LHC group (p>0.05). Conclusion: The adaptation of apical one-third by downpack-backfill was the best among the three groups, but there was no statistically significant difference among those groups.

Efficacy of rotary and reciprocating single-file systems on different access outlines for gutta-percha removal in retreatment: An in vitro study.

Introduction:The aim of this study is to compare the effectiveness of reciprocating and continuous rotary nickel-titanium instruments during retreatment performed through two different access outlines.Methodology:A total of 48 freshly extracted mandibular first and second premolars with single root and canal were selected. Initial root canal treatment was completed through a contracted endodontic cavity (CEC) design. Canals were instrumented with F2 ProTaper instrument, obturated with warm lateral condensation of gutta-percha with AH Plus sealer, and allowed to set for 30 days at 37°C and 100% humidity. For retreatment, specimens were divided into two groups (n = 24) on the basis of access outline, CEC or traditional endodontic cavity. Retreatment was initiated using ProTaper Retreatment instruments (D1–D3). Specimens were further divided (n = 12) and reinstrumented up to Neoniti 25/0.08 or WaveOne 25/0.08. Irrigation was performed using 3% sodium hypochlorite and 17% ethylene diamine tetraacetic acid. Retreatment time was recorded. Teeth were sectioned and photographed, and the percentage of remaining obturation material was measured.Results:Data were collected, and statistical analysis was performed using one-way analysis of variance and Tukey honestly significant difference multiple post hoc procedures (P < 0.05).Conclusion:None of the systems completely removed the root filling material from root canals. However, ProTaper/Neoniti instruments removed more GP when compared to Protaper/WaveOne instruments with both the access outlines. Both the instruments with traditional access outline required less time for removal of obturating material when compared to CEC.

Crack Formation Following Root-End Preparation in Roots with the Butterfly Effect.

Objective:To investigate apical cracks in roots that exhibit the butterfly effect and that have undergone apical resection and ultrasonic root-end cavity preparation. The effect of the obturation material was also studied.Methods:Forty extracted single-rooted teeth were decoronated at the cemento-enamel junction. Roots were viewed under a light microscope and coded according to the presence or absence of the butterfly effect. Canals were prepared using ProTaper Next instruments to size X3 and assigned to two obturation groups (gutta-percha and AH Plus, and ProRoot MTA alone). Each contained twenty roots (10 with the butterfly effect and 10 without the butterfly effect). Roots were resected perpendicular to their long axis, 3 mm from the apex, and cavities were cut using ultrasonic retrotips. Resin replicas were used for crack imaging from scanning electron micrographs. Statistical analyses were performed using Stata 13.1 (StataCorp, College Station, TX, USA).Results:Cracks occurred more frequently in teeth with the butterfly effect (80%), with this difference being significant (P=0.001). Most cracks (73%) ran buccolingually. Teeth obturated with MTA developed fewer cracks compared to those obturated with GP and sealer.Conclusion:Root-ends with the butterfly effect had a significantly higher number of buccolingual cracks following resection and ultrasonic root-end preparation. This might explain the development of some vertical root fractures, which usually run buccolingually. Canal obturation with MTA may be protective.

Evaluation of Intracanal Calcium Hydroxide Removal with Different Techniques: A Scanning Electron Microscope Study

This study aimed to evaluate the efficacy of Intracanal calcium hydroxide removal with different techniques. Seventy-five freshly extracted, non-carious, single canalled lower first premolars, having anatomic characteristics similar to each other, extracted for the orthodontic purpose were collected. After the root canal preparation, Calcium hydroxide was placed into the working length using lentulo spiral instrument till the medicament was visible at the apex. The specimens were segregated into three groups; Group 1: Rotary Files, Group 2: EndoVac system and Group 3: Ultrasonics. The evaluation was done with SEM in the coronal and apical third of the roots with a magnification of 1000x. The statistical analysis was done using statistical packages for social sciences (SPSS) software, version 20.0 for Windows (SPSS Inc., Chicago, IL). A p-value of less than 0.05 was considered significant statistically. Maximum removal of Ca(OH)2 was analyzed in the EndoVac system (2.90 ± 0.12) followed by the rotary files (1.76 ± 0.26) and least was seen with Ultrasonics (1.32 ± 0.14). The p-value of 0.001 was seen between the coronal and apical third with the EndoVac system which is statistically significant. The significant difference statistically was observed between Rotary Files vs. Ultrasonics at apical third and with the EndoVac system vs. Ultrasonics at coronal third as well as at the apical third with p-value 0.001. It can be concluded that the EndoVac technique was effective in removing Ca(OH)2 medicament from the coronal and apical third of the root canal significantly. Calcium hydroxide removal before the obturation was of priority as the Ca(OH)2 remnants have a negative impact of the ability for sealing the obturation material. Therefore, having a complete knowledge regarding the effective technique is much important.

A comparative evaluation of retrievability of Guttapercha, Resilon and CPoints for retreatment, using two different rotary retrieval systems - An ex vivo study

Introduction: Nonsurgical retreatment of failure cases requires regaining access to the entire root canal system through complete removal of the core filling material and sealer.Aims: The aim of this study was to compare the retrievability of gutta-percha (GP), Resilon, and CPoints, using Protaper and Mtwo rotary retreatment systems.Materials and Methods: Sixty freshly extracted mandibular premolars were decoronated and biomechanically prepared and obturated using GP, Resilon, and CPoints along with their corresponding sealers, in twenty teeth each. The teeth were divided into 6 groups of 10 teeth each. The filling was removed after 2 weeks with Protaper and Mtwo rotary retreatment files and the teeth were analyzed using cone beam computed tomography, to assess the remaining percentage volume of obturation material from each group.The data were statistically analyzed by ANOVA (post hoc test) followed Dunnett's t-test to evaluate statistical significant between the groups and paired t-test to find statistical significant before and after treatment.Results: The analysis of the results showed that the mean volume percentage of the residual material is low for Resilon group with Protaper retreatment file (16.35 ± 2.69%) and high in the groups obturated by CPoint and removed by Mtwo retreatment file system (29.67 ± 2.34%).Conclusions: Canals obturated with CPoints and endosequence bioceramic sealer are the least retreatable among the study groups.

Comparison of sealing ability of ProRoot mineral trioxide aggregate, biodentine, and ortho mineral trioxide aggregate for canal obturation by the fluid infiltration technique

Adequate seal of the root canal is necessary to prevent recontamination and ensure the long-term clinical success. The aim of this study was to evaluate the sealing ability of ProRoot mineral trioxide aggregate (MTA), Biodentine, and Ortho MTA as the root canal obturation materials using the fluid infiltration method. In this invitro study a total of 66 extracted human mandibular premolars were randomly divided into five groups according to the material used for the root canal obturation. Group I - ProRoot MTA (20 samples), Group II - Biodentine (20 samples), Group III - Ortho MTA (20 samples), Group IV - negative group (3 samples), and Group V-positive group (3 samples). MTA, Biodentine, and Ortho MTA were applied using a cotton-tipped K-file #30 and hand plugger into the root canals of each group. In Group 4 (negative control), no filling material was used. In Group 5 (positive control), a single gutta-percha size #40 was inserted into the root canal without using a sealer. The teeth were mounted and exposed to the fluid infiltrarion system. Statistical analysis was performed using Kruskal-Wallis test the level of significance was set at α = 0.05. Mean values of microleakage in MTA ProRoot, Biodentine and Ortho MTA groups were 1.83 ± 0.62, 1.95 ± 1.27 and 1.72 ± 0.83 μL in 8 minutes. No statistically significant difference was observed between the sealing ability of ProRoot MTA, Biodentine, and Ortho MTA (P = 0.091). Within the limitations of this study, microleakage values were similar to MTA ProRoot, Biodentine, and Ortho MTA using the fluid infiltration technique.

Effect of radiotherapy on the coronal-sealing ability of two different root canal sealing materials.

This study aimed to assess the coronal-sealing ability of two different root canal obturation materials: gutta-percha with AH Plus and Resilon with Epiphany SE between radiated and nonirradiated groups. Fifty-six extracted premolar teeth were randomly divided into two main groups according to the presence or absence of radiotherapy. Specimens were divided into two equal groups. In the radiotherapy group, a total dose of 60 Gy was delivered with 1.8 Gy/d fractions, 5 days a week, for 35 days. The root canals were obturated with either gutta-percha/AH Plus or Resilon/Epiphany SE canal sealer. The samples were then evaluated for the coronal-sealing ability using a centrifuging dye penetration test at 3000 rpm for 5 min in a 2% Rhodamine B solution. The degree of dye penetration was evaluated with a stereomicroscope. Although the sealing ability of both groups was not affected in radiotherapy, the coronal leakage values of Resilon/Epiphany SE slightly increased when radiation was applied (P > 0.05). Radiotherapy does not significantly affect the coronal-sealing ability of root canal obturation materials, gutta-percha/AH Plus and Resilon/Epiphany SE.

Clinical studies on core-carrier obturation: a systematic review and meta-analysis

BackgroundThis systematic review aimed to evaluate the clinical performance of core-carrier obturation in endodontic treatment.MethodsKeywords of “(core carrier OR Thermafil) OR (cold lateral condensation OR lateral condensation) OR (warm vertical condensation OR vertical condensation) AND (obturation OR root canal filling) AND clinical study” were searched for all obtainable publications up to year 2017 in the databases of PubMed, ScienceDirect, EMBASE, Scopus and Web of Science. The success rate, short-term postoperative pain, overfilling and adaptation of core-carrier obturation from clinical studies were selected. Reviews, laboratory studies, animal studies and irrelevant reports were excluded.Results1349 relevant articles were identified with 149 duplicated articles removed and 1173 irrelevant articles were excluded after screening. The titles and abstracts of the 19 identified articles were screened in the systematic review. The full texts of remaining articles were retrieved with data extracted for meta-analysis on the success rate, postoperative pain, overfilling and adaptation of obturation. The pooled success rate of core-carrier obturation was 83% (95% CI: 69%-91%). The pooled incidence of 1-day and 7-day short-term postoperative pain were 35% (95% CI: 15%-62%) and 6% (95% CI: 1-35%). The pooled proportion of teeth with overfilling and adequate adaptation of the obturation material were 31% (95% CI: 18%-50%) and 85% (95% CI: 75%-91%), respectively.ConclusionsThe success rate of endodontic treatment using core-carrier obturation was 83%. Short-term postoperative pain was not uncommon (24%). Most teeth (85%) had adequate adaptation using core-carrier obturation material, but a considerable amount of teeth (31%) had overfilling.

The Effect of Thickness on Sealing Ability of Calcium Enriched Cement as a Coronal Seal Barrier

Abstract Introduction: Thickness of a coronal seal barrier is an important factor for preventing microleakage. The aim of this in vitro study was to compare the sealing ability of two different thicknesses of calcium Enriched Mixture (CEM) cement as a coronal seal barrier. Methods: A total of 40 canals of extracted maxillary central incisors were instrumented and obturated using lateral compaction technique. The teeth were randomly divided into two experimental (N=15) and two control groups (N=5). For experimental groups, the obturation material was removed up to the experimental depths (2 and 3 mm) and were sealed with CEM. Sealing ability was evaluated by dye penetration method using pelikan ink and a stereomicroscope at x10 magnification and 0.01 mm accuracy. Data was analyzed using T-test and P<0.05. Results: The mean linear dye microleakage for the two thicknesses of CEM cement groups (2mm and 3mm) were 0.930 and 0.67 mm respectively. There was no statistically significant difference between the two groups (p<0.088). Conclusion: under the condition of this in vitro study, coronal microleakage in 2mm thickness of CEM cement had no statistically significant difference with 3 mm thickness of the material.

In Vitro the Effect of Canals Instrumented with Three Rotary Ni-Ti Systems on the Dislocation Resistanceo Guttafusion ® versus Single Cone Obturation Technique

Background: Complete seal of the root canal system following its chemo-mechanical debridement plays a pivotal role for achieving successful endodontic treatment. This can be established by reducing the gaps between the core filling material and root canal wall. Aim: To assess and compare the dislocation resistance of root canals obturated with GuttaFusion® and TotalFill BC sealer versus single cone obturation technique and TotalFill BC sealer after instrumentation of the canals with WaveOne, ProTaper Next and ProTaper Universal system. Material and Method: Sixty extracted human permanent mandibular premolars were conducted in the current study. The teeth were decorated and left the root with 15mm length; the roots were divided randomly into three main groups, twenty roots in each group. The roots were instrumented with different rotary systems using crown down technique according to the groups: (Group I) was instrumented with WaveOne files. (Group II) was instrumented with ProTaper Next system and (Group III) was instrumented with ProTaper Universal system. For each group the same irrigation regimen was used, 3 mL of 5.25% sodium hypochlorite and 3 mL of 17% EDTA to remove the smear layer. Then, Group I was also subdivided randomly into two subgroups of ten samples each, (Group I A) obturated with single cone gutta-percha and (Group I B) filled with GuttaFusion®. Group II was divided into (Group II A) obturated with single cone gutta-percha and (Group II B) filled with GuttaFusion®. Group III was divided into (Group III A) obturated with single cone gutta-percha and (Group III B) obturated with GuttaFusion®. In the present study, TotalFill BC sealer was used for all the tested groups. Then, the roots were embedded in clear acrylic resin and each root sectioned into three sections of 2mm thick (apical, middle and coronal). The push-out bond strength values represented by (MPa) unit was calculated by dividing the load on the surface area and the last was measured in collaboration with AutoCAD system software program. Failure mode analysis was carried out to examine the type of failure in each sample by using a stereomicroscope. Results: The results showed highly significant differences among the main groups that instrumented with different rotary systems (WaveOne, ProTaper Next and ProTaper Universal system). There were highly significant differences between the two obturation techniques of the subgroups (single cone gutta-percha versus GuttaFusion®). However; Gutta-Fusion® showed highest bond strength value than single cone obturation technique. The coronal third slices of all groups showed highest value of bond strength in comparison to the middle thirds and apical thirds. In the meantime, the middle third slices showed bond strength higher than that of the apical thirds for all groups. Statistical analysis was performed by using two way ANOVA and LSD tests. Conclusions: The instrumentation techniques and the obturation materials significantly affected the push-out bond strength values of obturation system. The highest value was appointed in root canals instrumented with ProTaper Universal System; obturated with GuttaFusion® and BC sealer, whereas, the lowest bond strength was appeared at canals instrumented with ProTaper Next; obturated with single cone gutta-percha and BC sealer.

Comparison sealability of root canal obturation using bioceramic sealer and methacrylate resin-based sealer

This study aimed to compare and analyze the obturation sealability using bioceramic sealer and methacrylate resin-based sealer. A total of 30 single-rooted teeth were prepared using ProTaper Next and randomly divided into two groups; the first group was obturated with bioceramic sealer (SB), while the second was obturated with methacrylate resin-based sealer (MRS). Coated gutta-percha was used as obturating material in both groups. Apical third marginal adaptation was evaluated by observing the dye penetration between the obturation material and the root canal walls on cross-sectioned samples. BS showed less microleakage in the apical third marginal adaptation than MRS. Obturation of root canal using BS has better sealing ability than MRS at the apical third.

Using erbium-doped yttrium aluminum garnet laser irradiation in different energy output levels versus ultrasonic in removal of root canal filling materials in endodontic retreatment.

Objectives:The objective of this study was to evaluate the efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation in different energy outputs versus ultrasonic in gutta-percha removal during the endodontic retreatment.Materials and Methods:A total of 21 extracted human lower premolars were divided into three groups (n = 7). Following the standardized preparation of the root canals with Wave One Rotary system and obturation with gutta-percha: Group I was treated with ultrasonic, Group II by Er:YAG laser with 40 mJ/Pulse, and Group III by Er:YAG laser with 50 mJ/Pulse for the removal of gutta-percha from the canals. Two extra teeth were treated by Er:YAG laser with 135 mJ/Pulse as control group. For all groups, time for gutta-percha removal was recorded. Samples were then splited into two halves and tested by scanning electron microscope and stereomicroscopic evaluation under different magnification power to observe the efficacy of each method used in the removal of gutta-percha.Results:Statistical analysis of Kruskal–Wallis suggested that there are significant difference between the groups in relation to removal time (P < 0.05) and 2 × 2 Mann–Whitney U-test among the groups revealed that there is no significant difference between 40 and 50 mJ laser outputs (P > 0.05), but ultrasonic versus 40 and/or 50 mJ laser outputs were significantly different (P < 0.05).Conclusions:Er:YAG laser beam was not so efficient when compared to ultrasonic to reach the deeper parts of the canals as it was asserted, thermal side effects and burning damages were observed on the root canal dentinal walls. Moreover, the delivery system was not flexible enough to compensate the curvature of the canal system even though we used more straight canals as the sample ones as well as more time-consuming than the ultrasonic and more clinical time, rendering it to be less efficient in the removal of the obturation material during endodontic retreatment procedures.