Calcium Hydroxide–Based Root Canal Sealers: A Review

The aim of this review was to consider laboratory experiments and clinical studies of calcium hydroxide–based root canal sealers. An extensive search of the endodontic literature was made to identify publications related to calcium hydroxide–based root canal sealers. The articles were assessed for the outcome of laboratory and clinical studies on their biological properties and physical characteristics. Comparative studies with other sealers were also considered. Several studies were evaluated covering different properties of calcium hydroxide–based sealers including physical properties, biocompatibility, leakage, adhesion, solubility, antibacterial properties, and periapical healing effect. Calcium hydroxide–based root canal sealers have a variety of physical and biological properties. Comparative studies reveal their mild cytotoxicity, but their antibacterial effects are variable. Further research is required to establish the tissue healing properties of calcium hydroxide in root canal sealers.     

Immediate and Long-Term Porosity of Calcium Silicate–Based Sealers

IntroductionOpen pores between endodontic sealer and root canal walls present potential niches for bacterial growth and migration pathways. The aim was to assess the internal and external porosity of calcium silicate–based sealers and to ascertain the long-term effect of storage in simulated body fluid on sealer porosity.MethodsSixteen single-rooted teeth were filled with gutta-percha and 1 of 4 root canal sealers: BioRoot RCS, EndoSequence BC, MTA Fillapex, or AH Plus. Obturated roots, stored in Hank's balanced salt solution, were scanned after 7 days and after 6 months by using micro–computed tomography at an isotropic resolution of 9.9 μm. Total, open, and closed porosity were calculated in the coronal, middle, and apical thirds. Data were statistically analyzed by using general linear model and paired t test (α = 0.05).ResultsSignificantly higher percentage of open than closed porosity was found in all groups. Initially, significantly greater open and total porosity were found for MTA Fillapex than for AH Plus. After 6 months, the percentage of open and total porosity increased in BioRoot RCS and MTA Fillapex and decreased in AH Plus and EndoSequence BC. Both initially and after storage, coronal region of all sealers had significantly greater total porosity than middle and apical regions, which were comparable.ConclusionsNone of the root fillings were void-free, with predominant open porosity persisting after long-term storage.     

Retrievability of Calcium Silicate–based Root Canal Sealers During Retreatment: An Ex Vivo Study

IntroductionThe retrievability of calcium silicate–based sealers (CSSs) during nonsurgical retreatment has been equivocal. This study compared the retrievability of 3 different CSSs using 1 of 3 different solutions or no solution.MethodsA total of 130 extracted teeth with a straight canal were decoronated to a standardized root length. The canals were instrumented to 35/.04 and divided into 3 groups (BC: EndoSequence BC sealer; EBC: EdgeBioceramic; NEO: NeoSEALERFlo), and each group was further divided into 4 subgroups (6% sodium hypochlorite; 5% acetic acid; carbonated water; no solution). After sealer placement, each master gutta-percha cone was placed intentionally 2 mm short of the working length (WL) to ensure the apical 2 mm was filled only with sealer. After storage for 21 days at 37°C and 100% humidity, retreatment was performed until apical patency was obtained. The operator was blinded to the CSS and solution used. Data were analyzed using analysis of variance to compare apical patency rates and the mock chair-times.ResultsOverall success rates for apical patency in BC, EBC, and NEO were 63.64%, 69.77%, and 100%, respectively. There was significantly higher apical patency rate in NEO than BC and EBC. The chair-time for NEO was significantly shorter than BC (P < .05) and EBC sealer (P < .001). There was no significant difference in the chair-time between BC and EBC sealer groups.ConclusionBC, EBC, and NEO sealers in a straight canal were consistently retrievable when no solution was used. Compared with no solution, the retrievability of BC, EBC, and NEO decreased when solutions were used.     

The Effect of Primary Root Canal Treatment on Dentinal Tubule Penetration of Calcium Silicate–based Sealers during Endodontic Retreatment

IntroductionThe aim of this study was to evaluate the effect of previous root canal treatment on dentinal tubule penetration of calcium silicate–based sealers during endodontic retreatment and to compare 2 different (commonly used and modified) tubule penetration depth measurement techniques.MethodsThe crowns of mandibular premolar teeth were removed, and root canals were prepared (ProTaper Universal; Dentsply Sirona, York, PA) and obturated using AH Plus (AH; Dentsply DeTrey, Konstanz, Germany), MTA Fillapex (MTAF; Angelus, Londrina, Brazil), and WellRoot ST (WRST; Vericom, Gyeonggi-do, South Korea); 0.1% red Rhod-2 dye (Chemodex, St Gallen, Switzerland) was added to the sealers. After storage for 3 weeks (37°C, 100% humid), the following sealer combination subgroups were created (the sealer used during the primary root canal treatment/the sealer used during the retreatment, n = 8): AH/AH, AH/MTAF, and AH/WRST; MTAF/AH, MTAF/MTAF, and MTAF/WRST; and WRST/AH, WRST/MTAF, and WRST/WRST. Green Fluo-3 dye (0.1%) was added to the sealers during retreatment. Sealer penetration depths were measured at 8 points and averaged, and the ratio of the retreatment sealer to the initial sealer was recorded as the mean tubule penetration depth ratio in the first technique, whereas the percentage of the circumferential penetration area ratios of the retreatment and initial sealers was calculated in the second technique. Statistical analyses were performed using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests.ResultsThe mean penetration depth of AH and MTFA was found to be higher at the coronal third region in the control groups (P < .05). Both methods showed a significant difference among the groups at the coronal and median regions (P < .05). The AH/WRST, MTAH/AH, MTAF/MTAF, MTAF/WRSTS, and WRST/WRST groups showed deeper tubule penetration (first technique, P = .01). Both techniques showed that the penetration depth of the sealers was the same at the apical region (P > .05), whereas a difference was found among the techniques at the coronal and median regions. The sealers used in the previous root canal treatment limited the penetration depth of the sealers used during the retreatment process (P < .05). When MTAF was used as the initial sealer, the penetration depth of the second sealer did not change, whereas if WRST was the initial sealer, the penetration depth of the sealers at the median and apical regions is negatively affected during the retreatment process (P < .05).ConclusionsPrevious root canal treatment affects the penetration depth of calcium silicate–based sealers. The use of AH Plus and MTA Fillapex during the retreatment process showed an advantage. Both measurement techniques showed similar performances at the apical region, whereas the results varied at the coronal and midcoronal regions; therefore, a more stable sealer penetration measurement technique is still necessary.     

Can Radiotherapy Affect the Apical Sealing Ability of Resin-Based Root Canal Sealers?

BackgroundThe authors conducted a study to assess the influence of radiotherapy on the apical sealing ability of one recently introduced resin-based root canal sealer and two sealers that have been in use for several years.MethodsThe authors divided 90 human maxillary anterior teeth into three groups according to the type of root canal sealer used and, using lateral condensation, obturated the roots with gutta-percha. They randomly divided all roots into two main groups according to the presence or absence of radiotherapy. For the groups that received irradiation, a dose of 60 gray was delivered in fractions of 1.8 Gy per day, five days a week for seven weeks. The authors then performed the centrifuging dye penetration test to determine apical leakage for each specimen.ResultsThe authors compared the specimens in the groups that received radiotherapy after endodontic treatment with the specimens in the groups that did not undergo radiotherapy after endodontic treatment. They found that mean apical leakage was slightly higher in the radiotherapy groups, but they did not observe any statistical difference between the groups (P > .05). In the groups that did not undergo radiotherapy, the mean apical leakage for the specimens in the MM-Seal (MicroMega, Besançon, France [not marketed in the United States]), AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) and AH 26 (Dentsply DeTrey GmbH) groups was 2.52 ± 0.42 millimeters, 2.85 ± 0.52 mm and 3.73 ± 0.41 mm, respectively. In the groups that underwent radiotherapy, the mean apical leakage for the specimens in the MM-Seal, AH Plus and AH 26 groups was 2.72 ± 0.55 mm, 2.96 ± 0.47 mm and 3.93 ± 0.61 mm, respectively.ConclusionThe apical sealing ability of the resin-based root canal sealers decreased slightly when radiotherapy was administered, although there was no statistically significant difference.Clinical ImplicationsClinicians can safely use a resin-based root canal sealer in patients receiving radiotherapy.     

Root Reinforcement after Obturation with Calcium Silicate–based Sealer and Modified Gutta-percha Cone

Introduction

A root canal obturated with a calcium silicate–based sealer (bioceramic sealer [BCS]) and a modified gutta-percha cone (bioceramic cone [BCC]) might improve the fracture resistance of the root. The objective of this study was to evaluate root reinforcement of a bioceramic cone/sealer (TotalFill; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) by investigating the fracture resistance, push-out bond strength, sealer penetration, and modulus of elasticity (MOE) in comparison with gutta-percha/AH Plus (Dentsply Maillefer, Tulsa, OK) (GP/AH).

Antibacterial Effect of Experimental Chlorhexidine-releasing Polymethyl Methacrylate–based Root Canal Sealers

IntroductionThis study evaluated the extent of chlorhexidine release from experimental chlorhexidine-containing polymethyl methacrylate (PMMA)-based root canal sealers prepared from a methacrylate-based sealer (SuperBond Sealer, Sun Medical Co Ltd, Shiga, Japan) and to examine its antimicrobial effect against Enterococcus faecalis using the direct contact test.MethodsChlorhexidine diacetate powder was mixed with PMMA powder of SuperBond Sealer to obtain chlorhexidine concentrations of 1 wt%, 2 wt%, and 3 wt%, respectively. PMMA disks were fabricated by self-curing the experimental PMMA powder and pure SuperBond sealer (control) and immersing them in distilled water at 37 °C for 12 weeks. Chlorhexidine release was analyzed by high-performance liquid chromatography. The direct contact test was performed on wells of 96-well plates coated with the respective experimental root canal sealers (n = 6). Bacterial suspensions were placed directly on the sealers that were aged for 12 weeks.ResultsThe cumulative chlorhexidine release after 12 weeks of water immersion was largely dependent on the amount of chlorhexidine powder that was initially incorporated into the PMMA-based sealer. Kruskal-Wallis test revealed that chlorhexidine concentration had a significant effect on the cumulative release (p = 0.0005). Experimental sealers with the incorporation of 2 wt% and 3 wt% chlorhexidine exhibited sustained antimicrobial effect for at least 4 weeks and 8 weeks.ConclusionThe incorporation of 2wt% and 3wt% chlorhexidine in the PMMA-based sealer had a long lasing antimicrobial effect against Enterococcus faecalis as a result of the turbidimetric determination of bacterial growth.     

Contemporary Methacrylate Resin–based Root Canal Sealers Exhibit Different Degrees of Ex Vivo Cytotoxicity When Cured in Their Self-cured Mode

The cytotoxicity of four methacrylate resin–based sealers was investigated by the 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide assay, which measures cell viability by assessing its succinate dehydrogenase activity. The sealers were polymerized in the self-cured mode to simulate the setting condition upon their extrusion into periradicular tissues. Disks were prepared from EndoREZ (Ultradent, South Jordan, UT), RealSeal (SybronEndo, Orange, CA), MetaSEAL (Parkell, Farmington, NY), and RealSeal SE (SybronEndo) together with positive and negative controls. After setting, they were placed in direct contact with rat osteosarcoma (ROS 17/2.8) cells and for 5 succeeding weeks after immersing in simulated body fluid (SBF). All sealers exhibited severe toxicity initially (week 0). EndoREZ and RealSeal remained severely toxic after five cycles of SBF immersion. Toxicity of the two self-etching resin-based sealers MetaSEAL and RealSeal SE decreased gradually over time. Transmission electron microscopy of cells exposed to RealSeal SE showed variable degrees of cell injury that reflect its toxicity status. Cells with intact mitochondria were identifiable after the sealer became noncytotoxic at week 5.     

Effect of Calcium Hydroxide and Double and Triple Antibiotic Pastes on the Bond Strength of Epoxy Resin–based Sealer to Root Canal Dentin

Introduction

The aim of this study was to evaluate the effects of calcium hydroxide (CH) and triple (TAP) and double (DAP) antibiotic pastes on the bond strength of an epoxy resin–based sealer (AH Plus Jet; Dentsply DeTrey, Konstanz, Germany) to the root canal dentin.

Methods

Sixty-four single-rooted human mandibular premolars were decoronated and prepared using the rotary system to size 40. The specimens were randomly divided into a control group (without intracanal dressing) and 3 experimental groups that received an intracanal dressing with either CH, DAP, or TAP (n = 16). The intracanal dressing was removed by rinsing with 10 mL 17% EDTA followed by 10 mL 2.5% sodium hypochlorite. The root canals were then obturated with gutta-percha and AH Plus Jet sealer. A push-out test was used to measure the bond strength between the root canal dentin and the sealer. The data were analyzed using 2-way analysis of variance and Tukey post hoc tests to detect the effect of the independent variables (intracanal medicaments and root canal thirds) and their interactions on the push-out bond strength of the root canal filling material to the root dentin (P = .05).

Results

The push-out bond strength values were significantly affected by the intracanal medicaments (P < .001) but not by the root canal thirds (P > .05). In the middle and apical third, the bond strength of the TAP group was higher than those of the CH and DAP groups (P < .05).

Conclusions

The DAP and CH did not affect the bond strength of the epoxy resin–based sealer. Additionally, the TAP improved the bond strength of the epoxy resin–based sealer in the middle and apical thirds.     

Cytokine Production and Cytotoxicity of Calcium Silicate–based Sealers in 2- and 3-dimensional Cell Culture Models

IntroductionThe aim of the present study was to assess the effects of different silicate-based sealers (ie, BioRoot RCS [Septodont, Saint Maur des Fosses, France], ProRoot ES [Dentsply Sirona, York, PA], and MTA Fillapex [Angelus, Londrina, PR, Brazil]) on cytokine production and viability of human periodontal ligament stem cells (PDLSCs). AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) was used as a reference material.MethodsPDLSCs were cultured either in 2-dimensional or 3-dimensional conditions (in 0.15%–0.5% PuraMatrix [BD Biosciences, Bedford, MA]) for 24 hours with eluates from set endodontic sealers. Additionally, the toxicity of eluates from endodontic sealers was evaluated using an in vitro root model experimental procedure. PDLSC viability was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. PDLSC culture medium was used for cytokine quantification (interleukin [IL]-6, IL-8, growth-regulated oncogene, IL,-4 and IL-10) using the HCYTMAG-60K-PX41 Milliplex kit (EMD Millipore, Burlington, MA).ResultsIn 2-dimensional culture conditions, BioRoot RCS revealed a good PDLSC viability rate. ProRoot ES had no effect on PDLSC viability regardless of the dilution. MTA Fillapex was strongly cytotoxic even at the lowest extract dilutions (1:1, 1:2, and 1:4). Encapsulation of PDLSCs in PuraMatrix tended to decrease the cytotoxic effect of the sealers. In the 3-dimensional in vitro root model experimental procedure, BioRoot RCS, ProRoot ES, and MTA Fillapex revealed a cytocompatibility pattern. Different calcium silicate–based sealers exhibited different proinflammatory cytokine production. BioRoot RCS greatly stimulated the release of IL-10 and, to a lesser degree, IL-4 by PDLSCs (P < .05).ConclusionsBioRoot RCS and ProRoot ES did not induce proinflammatory cytokines and promoted anti-inflammatory cytokine secretion by PDLSCs that may have a positive local impact by attenuating an initial inflammatory response.     

Prevalence of Apical Periodontitis in Root Canal–Treated Teeth From an Urban French Population: Influence of the Quality of Root Canal Fillings and Coronal Restorations

This cross-sectional study determined the prevalence of apical periodontitis in 1035 root canal–treated teeth from adult French patients and investigated the influence of the quality of canal fillings and coronal restorations on the periradicular status. Periapical radiographs were used for analyses, and teeth were classified as healthy or diseased according to the periapical index scoring system. Overall, the prevalence of apical periodontitis in root canal–treated teeth was 33%. Only 19% of the teeth had endodontic treatments rated as adequate. The success rate (number of healthy teeth) for cases with adequate endodontic treatment was 91%, which was significantly higher when compared with teeth with inadequate treatment (61%). Teeth with adequate restorations had significantly decreased prevalence of apical periodontitis (29%) as compared with teeth with inadequate restorations (41%). The combination of adequate endodontic treatment and adequate restorations yielded the highest success rate (93.5%). The quality of the endodontic treatment was the most important factor for success, although the quality of the coronal restoration also influenced the treatment outcome.     

Calcium Silicate–based Sealer Extrusion into the Mandibular Canal: 3 Different Recovery Outcomes—A Report of 3 Cases

The use of calcium silicate–based sealers (CSSs) is increasing in dentistry as a result of their favorable properties. The inadvertent extrusion of these sealers into the mandibular canal (MC) can result in temporary or permanent neurosensory alterations. Three different recovery outcomes of CSS extrusion into the MC after endodontic treatment of mandibular molars confirmed by cone-beam computed tomographic imaging are described. In Case 1, CSS from the mesiolingual canal of tooth #31 was extruded into the MC during obturation. The patient reported paresthesia. The symptoms of paresthesia were completely resolved by 9 months. In Case 2, CSS from the mesial canals of tooth #30 was extruded into the MC during obturation. A “plasmalike spreading pattern” of the extruded sealer was observed on the radiographs. The patient reported paresthesia and dysesthesia. In addition, the patient complained of hyperalgesia with heat and mechanical allodynia. The symptoms continued to persist during follow-up. At 22 months, the patient still reported persistent paresthesia, hyperalgesia, and mechanical allodynia, affecting the ability to eat. In Case 3, CSS from the distal canal of tooth #31 was extruded into the MC during obturation. The patient did not report any paresthesia or dysesthesia. All 3 patients elected a follow-up approach and monitoring rather than surgical intervention. These cases illustrate the need for the development of guidelines for the management of iatrogenic CSS extrusion into the MC because such an occurrence may result in permanent, temporary, or no neurosensory alterations.     

Volume of Voids in Retrograde Filling: Comparison between Calcium Silicate Cement Alone and Combined with a Calcium Silicate–based Sealer

IntroductionThe aim of this study was to compare the volume of voids between retrograde filling using calcium silicate cement alone and retrograde filling using a combination of calcium silicate cement with a calcium silicate–based sealer.MethodsTwenty single-rooted, extracted human teeth were instrumented with nickel-titanium files and obturated with gutta-percha. We resected the roots at a point 3 mm from the apex, prepared the root ends, and filled the root-end cavities with Endocem Zr (Maruchi, Wonju, Korea) or Endoseal MTA (Maruchi) plus Endocem Zr. Then, we scanned the prepared samples using micro–computed tomographic imaging and performed 3-dimensional reconstruction. The percentage volume of the gap between the canal wall and root-end filling was calculated along with the percentage volume of voids in the filling materials. All data were analyzed using the Mann-Whitney U test. Selected specimens were further observed using scanning electron microscopy.ResultsThere were no significant differences in the percentage volumes of the gaps and internal voids between the 2 groups. Both calcium silicate and the calcium silicate–based sealer exhibited good adaptation to the cavity wall.ConclusionsThe findings of our micro–computed tomographic and scanning electron microscopic analyses suggested that the volume of voids in retrograde filling using a combination of calcium silicate cement and calcium silicate–based sealer was comparable with that in retrograde filling using calcium silicate cement only. Calcium silicate–based sealers could be used in retrograde filling for clinical convenience without harmful effects on the quality of filling.     

Effects of Root Canal Preparation on Apical Geometry Assessed by Micro–Computed Tomography

IntroductionPrevious micro–computed tomography analyses of root canal preparation provided data that were usually averaged over canal length. The aim of this study was to compare preparation effects on apical root canal geometry.MethodsSixty extracted maxillary molars (180 canals) used in prior studies were reevaluated for analyses of the apical 4 mm. Teeth were scanned by using micro–computed tomography before and after canal shaping with FlexMaster, GT-Rotary, Lightspeed, ProFile, ProTaper, instruments or nickel-titanium K-files for hand instrumentation. Apical preparation was to a size #40 in mesiobuccal and distobuccal and #45 in palatal canals except for GT (#20) and ProTaper (#25 in mesiobuccal and distobuccal and #30 in palatal canals, respectively). Data for canal volume changes, the structure model index (quantifying canal cross sections), and untreated surface area were contrasted by using analysis of variance and Scheffé tests.ResultsMean mesiobuccal, distobuccal, and palatal canal volumes increased after preparation (P < .05), but differences were noted for preparation techniques. GT rendered the smallest (0.20 ± 0.14 mm³); K-files and ProFile showed the largest volume increases (0.51 ± 0.20 mm³ and 0.45 ± 021 mm³, P < .05). All canals were slightly rounder in the apical 4 mm after preparation indicated by nonsignificant increases in structure model index. Untreated areas ranged from 4%–100% and were larger in mesiobuccal and palatal canals than in distobuccal ones. Preparation with GT left significantly larger untreated areas in all canal types (P < .05); among root canal types, distobuccal canals had the least amounts of untreated surface areas.ConclusionsApical canal geometry was affected differently by 6 preparation techniques; preparations with GT instruments to an apical size #20 left more canal surface untouched, which might affect the ability to disinfect root canals in maxillary molars.     

In Vitro Fracture Resistance of Roots Obturated with Epoxy Resin–based,Mineral Trioxide Aggregate–based,and Bioceramic Root Canal Sealers

Introduction

The aim of this study was to evaluate the fracture resistance of teeth filled with 3 different endodontic sealers.

Methods

Seventy-five single-rooted extracted mandibular premolars were decoronated to a length of 13 mm. The teeth were randomly divided into 5 groups (n = 15 for each group). In group 1, the teeth were left unprepared and unfilled (negative control), and in group 2, the teeth were left unobturated (positive control). The rest of the roots were prepared by using the ProTaper System up to a master apical file size of F3: group 3, bioceramic sealer (Endosequence BC sealer) + gutta-percha; group 4, mineral trioxide aggregate–based sealer (Tech Biosealer Endo) + gutta-percha; and group 5, epoxy resin–based sealer (AH Plus Jet) + gutta-percha. All root specimens were stored for 2 weeks at 100% humidity to allow the complete setting of the sealers. Each specimen was then subjected to fracture testing by using a universal testing machine at a crosshead speed of 1.0 mm/min⁻¹ until the root fractured. The force required to fracture each specimen was recorded, and the data were analyzed statistically.

Results

The fracture values of groups 3 and 5 were significantly higher than those of group 4 (P < .05). There was no significant difference between groups 3 and 5 (P > .05).

Conclusions

In contrast to Tech Biosealer Endo, Endosequence BC and AH Plus Jet sealer increased the force to fracture in root-filled single-rooted premolar teeth.     

Biocompatibility and Bioactive Potential of New Calcium Silicate–based Endodontic Sealers: Bio-C Sealer and Sealer Plus BC

IntroductionBio-C Sealer (BC; Angelus, Londrina, PR, Brazil) and Sealer Plus BC (SPBC; MK Life, Porto Alegre, Brazil) are new ready-to-use bioceramic endodontic sealers. The aim of this study was to evaluate the biocompatibility and bioactive potential of BC and SPBC sealers in comparison with AH Plus (AHP; Dentsply DeTrey Gmbh, Konstanz, Germany) in subcutaneous tissue of rats.MethodsPolyethylene tubes filled with materials and empty tubes, serving as the control group, were implanted in the subcutaneous tissues of rats. After 7, 15, 30, and 60 days, the tubes with connective tissue were removed, and inflammatory cells (ICs)/mm² and immunolabeled cells for interleukin (IL)-6 were evaluated. Osteocalcin and von Kossa analysis were also performed. Data were submitted to analysis of variance and Tukey tests, with a significance level of 5%.ResultsAt 7 days, SPBC showed lower ICs than BC (P < .05). AHP exhibited greater immunolabeled cells for IL-6 (P < .05). After 15 days, BC showed lower ICs and IL-6 compared with other materials. At 30 days, SPBC and AHP showed higher values for ICs (P < .05). After 60 days, calcium silicate sealers did not show statistical difference (P > .05) for ICs and IL-6, with values lower than AHP (P < .05). The materials showed positive structures to von Kossa staining. BC exhibited osteocalcin labeling in all periods. SPBC showed osteocalcin labeling from 15–60 days. AHP and the control group did not exhibit osteocalcin labeling.ConclusionsBC and SPBC sealers are biocompatible and present bioactive potential.     

Radiographic Identification of Separated Instruments Retained in the Apical Third of Root Canal–filled Teeth

Introduction

The aim of the study was to compare the diagnostic ability to radiographically detect separated stainless steel (SS) versus nickel-titanium (NiTi) instruments located at the apical third of filled root canals with either AH 26 (Dentsply DeTrey GmbH, Konstanz, Germany) or Roth sealer (Roth International Ltd, Chicago, IL).

Methods

Sixty single-rooted extracted human teeth with 1 straight root canal were instrumented to a size 25 apical diameter. In 40 teeth, apical 2-mm segments of SS (n = 20) or NiTi (n = 20) files were intentionally fractured in the apical part of the root canal. The remaining 20 teeth without fractured files served as a control group. Subsequently, the root canals were filled using laterally condensed gutta-percha and either AH 26 sealer (AH) or Roth sealer (Roth). All teeth were radiographed using conventional Kodak film (Eastman Kodak Co, Rochester, NY) and a charge-coupled device digital sensor. The evaluation of the images for the presence of a fractured instrument was performed independently by 2 blinded observers. The data were statistically analyzed using McNemar and Fisher exact tests.

Results

The kappa values were 0.76 and 0.615 for the first and second observers, respectively, and 0.584 between the observers. There were no significant differences in the diagnostic ability between digital and conventional radiography or the different root canal sealers (AH vs Roth, P > .05). The sensitivity to detect fractured SS was significantly higher than NiTi (P < .05).

Conclusions

It may be difficult to radiographically detect a retained separated instrument. It is easier to radiographically detect fractured SS than NiTi instruments retained at the apical third of the root canal.     

Does Maintaining Apical Patency during Instrumentation Increase Postoperative Pain or Flare-up Rate after Nonsurgical Root Canal Treatment? A Systematic Review of Randomized Controlled Trials

Introduction

The concept of maintaining apical patency (AP) is a controversial issue in endodontics. The primary objectives of this systematic review of randomized controlled trials (RCTs) were to determine the influence of maintaining AP during instrumentation on postoperative pain severity and the prevalence of flare-ups. A second objective was to assess the effect of maintaining AP on the use of analgesics.

Cytotoxicity and the Effect of Temperature on Physical Properties and Chemical Composition of a New Calcium Silicate–based Root Canal Sealer

IntroductionThe suitability of EndoSequence BC Sealer (BC Sealer; Brasseler USA, Savannah, GA) for warm vertical compaction has been questioned. The aim was to evaluate the cytotoxicity and the effect of heating on the physicochemical properties of a new calcium-based root canal sealer (EndoSequence BC Sealer HiFlow [HiFlow]) in comparison with EndoSequence BC Sealer.MethodsHuman periodontal ligament fibroblasts were incubated for 1, 2, or 3 days with material extracts of different concentrations, and cell viability was evaluated by Cell Counting Kit-8 (Enzo Life Sciences Inc, Burlington, Ontario, Canada). The setting time, flow, film thickness, microhardness, radiopacity, and radiopacity of the 2 sealers were measured according to ISO 6786/2012. The continuous changes in viscosity were tested by a stress-controlled rheometer at shear rates ranging from 0.01–10 s⁻¹ and different temperatures, and chemical composition was assessed by Fourier-transform infrared spectroscopy.ResultsCell viability was significantly decreased on day 3 for the 1:4 diluted extract from both materials. The setting time, microhardness, and solubility of HiFlow were similar to BC Sealer at 37°C and 100°C. HiFlow had significantly higher flow and radiopacity than BC Sealer at room temperature (P < .05), and when heated, HiFlow retained its higher flow and lower film thickness (P < .05). Both sealers showed decreasing viscosity with increasing shear rate, and at a shear rate of 0.01 and 0.1 s⁻¹, HiFlow exhibited lower viscosity than BC Sealer at all temperatures measured. The chemical composition of the 2 sealers was not changed by heating.ConclusionsHiFlow showed better performance on flow/viscosity and film thickness, especially under high temperatures, which are generated by the commonly used warm vertical compaction technique.     

Histologic Investigation of Root Canal–treated Teeth with Apical Periodontitis: A Retrospective Study from Twenty-four Patients

This study intended to examine histologically root canal–treated teeth evincing apical periodontitis lesions and correlate the findings with clinical observations. Specimens were obtained from 24 patients (12 asymptomatic and 12 symptomatic) by extraction or endodontic surgery and consisted of roots or root tips and the associated pathologic lesion. Specimens were processed for histologic analysis, and serial sections were evaluated. Findings were correlated with clinical observations according to the presence or absence of symptoms. The mean period elapsed from treatment to specimen retrieval in the asymptomatic group was 7.5 years, as compared with 2.2 years in the symptomatic group. All specimens exhibited periradicular inflammation. Bacteria were visualized in all cases, except for 1 specimen from the asymptomatic group in which a foreign body reaction to overfilled material was the probable reason for emergent disease in a previously vital case. Irrespective of the presence of symptoms, bacteria were always located within the root canal system, although they were also observed in the periradicular tissues in 1 asymptomatic and 4 symptomatic teeth. In general, intraradicular bacterial colonization was heavier in symptomatic failed teeth. The present findings support the role of intraradicular infections, usually in the form of biofilms, as the primary cause of endodontic treatment failure.