A comparative evaluation of gutta-percha filled areas in curved root canals obturated with different techniques

The use of sonic and ultrasonic activation of endodontic sealer to improve sealer filling quality in the root canal: a scoping review

This scoping review aimed to map whether the use of sonic and ultrasonic methods to activate the endodontic sealer improves the sealer filling quality in the root canal, considering the bond strength and intratubular penetration to the root dentin as evaluation criteria. The study protocol was prospectively registered and is available online ( https://osf.io/x5fma/ ). Reporting was based on PRISMA Extension for Scoping Reviews. The search was performed in Embase, PubMed, Scopus, and Web of Science. We selected studies without time and language restrictions that used sonic or ultrasonic methods to activate endodontic sealer, whose outcomes were bond strength and intratubular penetration. Three researchers independently selected the articles and collected data. Of 1422 articles, 19 were read in full and 13 studies were included. The vast majority of studies opted for direct activation of the endodontic sealer. The most investigated sealers were the epoxy resin-based sealers, and the ultrasonic activation method was the most explored. For the bond strength outcome, there was a trend toward higher values when the sealer was activated ultrasonically, but the findings seem to be divergent. The sonic activation was not effective for its intended purpose. For the outcome of intratubular penetration, the vast majority of studies indicate that the use of sonic and ultrasonic methods to activate the endodontic sealer is capable of increasing intratubular penetration. The use of sonic and ultrasonic methods to directly activate the endodontic sealer can increase the intratubular penetration of the sealer, but their benefits on the bond strength are uncertain.

Penetration of Calcium Silicate and Epoxy Resin Sealers Into the Lateral Canals

OBJECTIVES

The aim of this research was to compare the penetration ability of calcium silicate-based sealers (iRoot SP and TotalFill BC HiFlow) and an epoxy resin-based sealer (AH Plus) into the lateral canals using the single-cone (SC) or continuous wave compaction (CW) obturation techniques.

METHODS

Ninety single-rooted human teeth received canal instrumentation and diaphanisation before artificial lateral canals were created at 3 different root levels. The specimens were randomly allocated into 6 groups based on the combination of obturation technique and sealer used. Radiographic and photographic measurements evaluated the percentage of sealer penetration. Statistical analysis was performed to compare the penetration ability amongst different types of sealers, obturation methods, and root levels.

RESULTS

Although TotalFill BC HiFlow sealer combined with the CW technique demonstrated greater sealer penetration at the coronal level (P < .05), the overall penetration ability of iRoot SP, TotalFill BC HiFlow, and AH Plus was not significantly different. The deepest sealer penetration was observed at the apical root level.

CONCLUSIONS

All sealers showed similar penetration abilities into the lateral canals using the SC or CW techniques in vitro. Calcium silicate-based sealers have comparable penetration ability into lateral canals compared to epoxy resin-based sealers using SC or CW obturation techniques.

Endodontic Outcome of Root Canal Treatment Using Different Obturation Techniques: A Clinical Study

OBJECTIVE

To evaluate the clinical outcome of root canal treatment by obturation technique, root canal filling quality, and tooth- and patient-related variables.

METHODS

This clinical study investigated the endodontic outcome of 114 teeth treated between the years 2009 and 2012. Three different obturation methods were used: (1) adhesive obturation using the continuous wave of condensation technique with Resilon® (CWR), (2) matching-taper single-cone technique with gutta-percha and AH Plus® (SCGP), and (3) matching-taper single-cone technique with gutta-percha and GuttaFlow® (SCGF). Pre- and postoperative periapical radiographs were performed to detect the presence of endodontic lesions (PAI classification) and to assess the quality of both the obturation and the restoration. Tooth- and patient-related data were collected.

RESULTS

The overall endodontic success rate was 75.4% after a mean observation period of 6.3 years. There were no significant correlations between the type or overall quality of obturation and the treatment outcome. Teeth with preoperative lesions had the highest odds ratio (factor of 4.98) for endodontic failure. Tooth- and patient-related variables had no significant effect on endodontic outcome.

CONCLUSIONS

The preoperative periapical status of teeth requiring endodontic treatment was a substantial prognostic factor for endodontic outcome, whereas the type of obturation material or technique did not affect it.

Evaluation of the efficacy of rotary and reciprocating systems for the removal of filling material for various root canal filling techniques

Background

This study aimed to evaluate the efficacy of various filling and retreatment techniques for oval-shaped root canals.

Methods

Sixty distal roots of mandibular molar teeth were included in the study. The roots were prepared using the ProTaper Next (PTN) X4 rotary system and irrigation with 2.5% NaOCl. The roots were then divided into three groups and filled with Total Fill BC Sealer (FKG Dentaire) using three different techniques (n=20): single cone (SC), GuttaCore (GC), and warm vertical condensation (WVC). The retreatment procedure was performed using two different instrumentation techniques: Reciproc 50 (R50) and PTN X5 (n=10). To analyze the remaining filling material, the roots were divided buccolingually in two parts with the help of diamond separators, and photographs were taken at x16 magnification using a dental operating microscope (DOM). The ratio of the remaining filling materials was calculated using image analysis software and statistically evaluated using the Kruskal-Wallis test.

Results

None of the assessed retreatment procedures completely removed the filling materials from the root canals. For both instrumentation techniques, more root canal filling material remained in the WVC group (P<0.05).

Conclusion

The GC filling technique had a higher cleaning percentage than the WVC and SC techniques in the coronal region. The R50 system was found to be superior to the PTN X5 system for retreatment, and the root canal fillings applied using the WVC technique were more difficult to remove than the fillings applied using the other techniques.

New Ultrasonic Tip for Root Canal Filling of the Mesial Canals of Mandibular Molars with Isthmus: A Laboratory Evaluation Using Computed Microtomography

INTRODUCTION

The obturation quality of the mandibular molar mesial canals and isthmuses with two thermoplastic techniques, ultrasonic vertical condensation (UVC) and continuous wave of condensation (CWC), was evaluated using computed microtomography (μCT).

METHODS

Thirty-six human mandibular molars had been previously scanned and analyzed using μCT for mesial roots with morphologically similar isthmuses for this study. Coronal access and confirmation of foraminal patency were performed, and the actual length of the teeth was established using a clinical microscope (40X magnification). The canals were prepared using ProTaper Gold instruments up to #F3, with 2.5% sodium hypochlorite as the irrigant solution, followed by a passive ultrasonic irrigation protocol. The specimens were randomly divided into the UVC and CWC groups based on the obturation technique to be used. Obturation was performed with #F3 gutta-percha cones cemented using AH Plus Jet sealer. The μCT scans were performed after 15 days, and the images were evaluated by a calibrated examiner blinded to the experimental groups to determine the filling rate of the entire canal area, including the main canal and isthmus. Student's t-test was used for statistical analysis; P values ≤0.05 were considered significant.

RESULTS

Neither of the thermoplastic obturation techniques achieved complete filling of the canals (86.3% for UVC and 91.4% for CWC), with a statistically significant difference between them (P = .029).

CONCLUSIONS

Under the conditions of the study, it can be concluded that none of the techniques completely filled the canal/isthmus of the mandibular molars; however, the CWC exhibited better performance.

Single Cone Obturation versus Cold Lateral Compaction Techniques with Bioceramic and Resin Sealers: Quality of Obturation and Push-Out Bond Strength

Objectives

This study compared the obturation quality and push-out bond strength of single cone obturation (SCO) and cold lateral compaction (CLC) with AH-Plus and Sure Seal Root (SSR).

Materials and Methods

This in vitro experimental study was conducted on 88 single-rootedsingle-canal teeth with straight roots that were randomly divided into four groups (n = 22). All teeth were decoronated and underwent cleaning and shaping. Obturation was performed with AH-Plus and SCO technique in group 1 (SAH), AH-Plus and CLC technique in group 2 (LAH), SSR and SCO technique in group 3 (SS), and SSR and CLC technique in group 4 (LS). The roots were then sectioned into 3-mm thick slices and underwent digital photography at x25 magnification to assess the quality of obturation in the coronal, middle, and apical thirds by Image J software. The PBS was measured by a universal testing machine. The mode of failure was also determined under a stereomicroscope.

Results

The PBS was significantly higher in the LSS group than LAH and SAH groups, and also in the SSS group than the SAH group in all sections. The PBS in the LSS group was significantly higher than SSS in the coronal and middle thirds. Voids were significantly lower in LAH than in the SAH group in all sections. In LSS, voids in the coronal third were significantly lower than in LAH. In the middle third, voids in SSS were significantly lower than in SAH. The groups had no significant difference in the mode of failure (P > 0.05). The mean percentage of gutta-percha in the use of AH-Plus sealer was significantly higher than SSR (P < 0.05). The mean percentage of gutta-percha in the coronal third was lower than that in the middle and apical thirds (P < 0.05).

Conclusion

SSR showed higher PBS and less voids than AH-Plus. High PBS of the CLC/SSR group showed that CLC should still be preferred to SCO, and in the case of using SCO, SSR should be preferred to AH-Plus.

Comparative Analysis of Temperature Variation with Three Continuous Wave Obturation Systems in Endodontics: An In Vitro Study

The aim of this study was to assess temperature changes with different continuous wave obturation systems when downpacking to 2 mm and 4 mm from the apical foramen in an open system not simulating the surrounding biological structures at body temperature. Sixty single-rooted teeth were divided into three groups: (A) Dia-Duo® (DiaDent Group International, Cheongju-si, Korea), (B) Elements Free® (Kerr Corporation, Orange, CA, USA) and (C) Calamus® (Dentsply Sirona, Ballaigues, Switzerland). The root canals were instrumented with Protaper Gold (Dentsply Sirona, Ballaigues, Switzerland) to size F2 (25.08). The root canals were filled by a continuous wave using an AH Plus® sealer (Dentsply Sirona). Temperatures during the obturation procedure were measured by a thermal imaging camera (Testo 875-1®) perpendicular to a vice where the teeth were held at −2 mm and −4 mm from the apical foramen. Comparisons were made by applying Student’s t-test and ANOVA (p = 0.05). The continuous wave technique at −2 mm with the Dia-Duo system® emitted average temperatures of 37.3 °C, Elements Free® emitted 39.85 °C and Calamus® emitted 40.16 °C. At −4 mm, the Dia-Duo system® emitted average temperatures of 34.81 °C, Elements Free® emitted 33.73 °C and Calamus® emitted 32.91 °C. There were significant differences between continuous waves at −2 mm and at −4 mm (p < 0.05). Dia-Duo® was the only system that did not present significant differences between the two lengths (p = 0.197). Regarding the heat emitted, the best system was Elements Free®, since, at −2 mm, it emitted the highest temperature without going above 47 °C. The Dia-Duo® system had lower temperatures. It could be concluded that not all systems transmit the same temperature to the apex and, therefore, to the periapical tissues. The surrounding conditions, such as temperature and humidity, have not been considered in this study.

Comparison of Two Root Canal Filling Techniques: Obturation with Guttacore Carrier Based System and Obturation with Guttaflow2 Fluid Gutta-Percha

Introduction: The aim of the present study was to compare the quality of the root canal obturation obtained with two different techniques, i.e., thermoplastic gutta-percha introduced through a carrier (GuttaCore) and fluid gutta-percha (GuttaFlow2). Materials and Methods: The study included 40 permanent single-rooted human teeth, divided into two groups and obturated with Guttaflow (group G) and with GuttaCore (group T). The teeth were fixed and transversely sectioned, they were examined by scanning electron microscopy. The dentin–cement–gutta–percha interface and the percentage of voids produced by the two techniques were statistically analyzed. Results: GuttaCore showed a better filling in the apical third of the canal with a percentage of voids equal to 5%. GuttaFlow showed a lower percentage of voids in the middle and coronal thirds of the canal, 1.6% of coronal voids. Statistical analysis showed a statistically significant difference in the percentage of voids in the two groups (GuttaCore and Guttaflow2) in each portion. Conclusions: GuttaFlow2 seems to flow optimally in the middle and coronal third of the canal, with greater difficulty in filling the apical third. Due to the rigidity of the carrier, GuttaCore is able to reach better the most apical portions of the canals, with greater difficulty in creating the three-dimensional seal at the level of the middle third and coronal third.

A critical analysis of research methods and experimental models to study root canal fillings

Canal filling materials and techniques have been one of the most studied topics in Endodontics. A simple search using the mesh term "root canal filling" in PubMed revealed more than 11,000 articles, an impressive number that is much higher than "root canal disinfection" (5,544 articles) or even the popular "root canal preparation" (8,527 articles). The overriding importance attributed to root filling procedures is not merely intuitive. It derived from the appealing relevance given by the appearance of the white lines in common radiographs grounded on retrospective clinical data that had identified the quality of a root filling as one of the major causes of treatment failure (lack of healing). Since the publication of the Washington study, impressive efforts have been made for the release of new materials and techniques, as well as, for the development of a plethora of laboratory methods to assess the quality of root filling procedures. This narrative review aims to address and discuss the most relevant laboratory methods to assess the root canal filling. Since filling quality improvements have not translated into higher success rates, as reported in longitudinal clinical studies, more than to deliver a simple methodology-based review, this paper aims to present an in-depth critical view on the assessment of laboratory methods used to study the filling materials and techniques. Recent data indicate that the long-term dimensional stability/degradation over time of endodontic sealers plays a central role in the treatment outcome. In this context, laboratory methods should be developed focusing on predicting, at least to some degree, the long-term clinical behaviour of root canal fillings, rather than simply ranking different materials or techniques.

Evaluation of curved root canals filled with a new bioceramic sealer: A microcomputed tomographic study using images with different voxel sizes and segmentation methods

The aim of this study was to investigate the filling ability of a new premixed bioceramic sealer in comparison with an epoxy resin-based sealer in curved root canals using different segmentation methods and voxel sizes in micro-CT images. Twelve curved mesial roots of mandibular molars with two separated canals were selected. All root canals were prepared by using HyFlex EDM files size 25/.08 and filled by the single cone technique and Bio-C Sealer or AH Plus (n = 12). The samples were scanned by micro-CT at 5 μm. The images were analyzed at 5, 10, and 20 μm for the volumetric analysis of voids in filling. Visual image segmentation was performed by two examiners, and the automatic segmentation was accomplished for comparison. Radiopacity of the sealers was evaluated by radiographic analysis. Data were submitted to the two-way ANOVA and non-paired t tests at a significance level of 5%. AH Plus had the highest radiopacity (p < .05). Root canals filled with AH Plus or Bio-C had similar low percentage of voids (p > .05). There was no difference interobserver, which had similar results to those obtained with automatic segmentation for all voxel sizes evaluated (p > .05). Bio-C Sealer had appropriate filling ability. Visual and automatic segmentation can be applied to micro-CT images with voxel sizes from 5 to 20 μm to evaluate the filling of sealers with adequate radiopacity. Automatic segmentation should be used as a faster method.

Heating stability, physical and chemical analysis of calcium silicate-based endodontic sealers

AIM

To evaluate possible modifications in root canal sealers subjected to a variety of heating conditions using vibrational spectroscopy and analysis of physical and chemical properties.

METHODOLOGY

EndoSequence BC Sealer HiFlow, Bio-C Sealer, BioRoot RCS and AH Plus were analysed chemically using Raman spectroscopy (25-220 °C) and Fourier-transform infrared spectroscopy (FT-IR) (37-100 °C ). For FT-IR, the materials were tested individually and mixed with root dentine powder. Scanning electron microscopy (SEM) and coupled energy dispersive spectroscopy (EDS) were used to evaluate surface and chemical elements. ISO 6876-2012 and ASTM-C266-07 specifications were followed to evaluate flow, setting time (moist and dry), solubility and radiopacity. Also, pH analysis at 37 and 100 °C was performed. Shapiro-Wilk and Mixed ANOVA (within and between the effects of the subjects), Levene, and a post hoc analyses with Bonferroni correction were performed (P < 0.05).

RESULTS

Vibrational spectroscopy revealed peaks of tricalcium silicate, dicalcium silicate and zirconium dioxide. Chemical changes in the Raman spectra during heating were discrete, as the inorganic content predominated the signalling for all root canal sealers. FT-IR analysis exhibited spectral changes in water absorption for EndoSequence BC Sealer HiFlow and Bio-C Sealer, probably related to dehydration. For BioRoot RCS and AH Plus, no significant chemical changes were observed. Bio-C Sealer exhibited a band of polyethylene glycol only after heating to 100 °C, probably related to its thermal decomposition. SEM/EDS analysis corroborated the composition results observed in vibrational spectroscopy for all materials. Heating to 100 °C significantly changed the flowability of all calcium silicate-based sealers with a wide variation in setting times at both temperatures, along with solubility levels above ISO standards. For all tested sealers, radiopacity fulfilled the requirements, and pH exhibited alkaline values.

CONCLUSIONS

The tested calcium silicate-based sealers were affected by heating. Calcium silicate-based root canal sealers had high solubility which is a concern for their clinical use. AH Plus was the only root canal sealer that was stable after heating.

Effects of Ultrasonic Activation on Root Canal Filling Quality of Single-Cone Obturation with Calcium Silicate-Based Sealer

Background: We evaluated the effects of ultrasonic activation on root canal filling quality of the single-cone (SC) obturation technique with calcium silicate sealers and gutta percha cones. Methods: Thirty-six human single-rooted premolars were obturated with gutta percha and sealer. For the continuous wave (CW) group (n = 12), AH Plus with a continuous wave technique was used. The SC group (n = 12) received EndoSequence BC sealer with a single-cone technique. The SCU (SC with the addition of ultrasonic activation) group (n = 12) received the same treatment. Micro-computed tomography was used to scan the teeth, and the void volume within the root canal was evaluated at the apical, middle, and coronal levels. Then cross-sections were observed under a light microscope and scanning electron microscope (SEM). Results: Void volume was significantly lower in the SCU group than in the CW and SC groups. There were no statistically significant differences between the CW and SC groups. The SCU group had fewer voids than the CW and SC groups in the coronal and middle third areas. Specimens showed no apparent gaps or voids in any group. SEM images revealed both gap-free and gap-containing regions at different levels in all groups. Conclusions: Single-cone obturation with calcium silicate-based sealers might obtain enhanced filling quality when used with ultrasonic activation.

Effect of obturation technique using a new bioceramic sealer on the presence of voids in flattened root canals

The aim of this study was to evaluate the filling ability of a new ready-to-use calcium silicate-based sealer using thermoplastic or single-cone technique in flattened root canals. Twenty-four flattened distal canals of mandibular molars with a buccolingual diameter 4 or more times larger than the mesiodistal diameter were selected. The root canals were prepared and filled (n = 12), according to the following techniques: thermoplastic or single-cone technique using Bio-C Sealer. The teeth were scanned using Skycan 1176 micro-computed tomography (micro-CT) - voxel size 8.74 µm, before and after filling the root canal. The percentage of voids in the filled root canals was evaluated, and the data were statistically analyzed using the unpaired t-test (α = 0.05). The root canals filled using the thermoplastic technique created a smaller percentage of voids in the cervical/middle thirds than those filled using the single-cone technique (p < 0.05). There was no difference in the percentage of voids using either technique in the apical third (p > 0.05). The flattened root canals in the cervical/middle thirds were better filled using the ready-to-use calcium silicate-based sealer associated to the thermoplastic technique, compared with the single-cone technique. In the apical third, the techniques showed similar filling ability.

Filling Ability and Flow of Root Canal Sealers: A Micro-Computed Tomographic Study

This study evaluated by micro-computed tomography (μCT) the filling ability in curved root canals, besides the flow of AH Plus (AHP) and Neo MTA Plus (NMTAP) sealers using different methodologies. Mandibular molars mesial roots with two root canals and degree of curvature between 20° and 40° were selected. The specimens were prepared with the ProDesign R system up to size 35.05 and were filled with the sealers by a continuous wave of condensation technique, Thermo Pack II (n=12). The teeth were scanned using μCT after root canal preparation and obturation. The volumetric percentage of filling material and voids were calculated. Flow was evaluated based on ISO 6876/2012 (n=10). Flow and filling were also evaluated in μCT using a glass plate with a central cavity and four grooves from the central cavity (n=6). Flow was linearly calculated into the grooves. The central cavity filling (CCF) and lateral cavity filling (LCF) were calculated in mm³. Data were submitted to non-paired t test with a significance threshold at 5%. The percentage of filling and voids between the root canals filled with AHP or NMTAP was similar (p>0.05). NMTAP presented the lowest flow in conventional test (p<0.05). Using μCT, sealers had similar CCF, LCF and linear flow (p>0.05). In conclusion, NMTAP and AHP had similar filling ability in curved mesial root canals of mandibular molars without presence of isthmus. Although AHP presented better flow than NMTAP using ISO methodology, there was no difference between these materials regarding volumetric filling when evaluated by μCT.

Sealing Ability of AH Plus and GuttaFlow Bioseal

The objective of root canal obturation is to achieve a fluid-tight seal. Recently, GuttaFlow bioseal (GB), a root canal sealer composed of polydimethylsiloxane, gutta-percha particles, and bioactive glass ceramics, has been developed, to enhance the sealing ability of root canal filling material. The objective of this study was to assess the sealing ability of GB using a subnanoliter-scaled fluid-flow measuring device and to compare with that of AH Plus (AH). The fluid flow in root canal-filled teeth using either gutta-percha cone (GP) with AH (GAR; n = 10) or GP with GB (GBR; n = 10) and in GP inserted in AH blocks (GA; n = 10) or GP inserted in GB blocks (GB; n = 10) was measured. In addition, fluid flow in sealer blocks of AH (A; n = 10) and GB (B; n = 10), which served as negative controls, was measured. Root canal-filled teeth using GP without any sealer (GR) acted as positive controls (n = 10). The leakage was obtained by calculating the volume of moved water by time (s), after stabilization of the fluid flow was achieved. Statistical analysis was performed using the Kruskal–Wallis test and Mann–Whitney U-test with Bonferroni correction. A p value less than 0.00238 (0.05/21) was considered significantly different. The mean leakages (nL/s) in the groups are as follows: GAR, 0.0958 ± 0.0543; GBR, 0.0223 ± 0.0246; GA, 0.0644 ± 0.0803; GB, 0.0267 ± 0.0182; A, 0.0055 ± 0.0057; B, 0.0052 ± 0.005; and GR, 0.2892 ± 0.3018. The mean leakage in the GBR group was lower than that in the GAR group (p = 0.001), while the mean leakages in the GA and GB groups were not significantly different. GuttaFlow bioseal can be useful in single-cone obturation technique.

Evaluation of different root canal filling techniques in severely curved canals by micro-computed tomography

AIM

To fill the severely curved root canals with different filling techniques and to compare these techniques using micro-computed tomography (micro-CT).

MATERIALS AND METHODS

Sixty extracted mandibular first molars (degree of root canal curvature >25°) were selected. All samples were divided into four groups and filled with one of the following techniques: lateral condensation, single-cone, continuous-wave obturation, and core carrier. After they were scanned by micro-CT, the total area, filled area and void area of the root canal were calculated. The Mann-Whitney U and Kruskal-Wallis tests were used for statistical analysis (p < 0.05).

RESULTS

It was shown that significantly more filling material was used in the lateral condensation and core carrier technique groups at 2 and 5 mm than in the single-cone and continuous-wave obturation technique groups (p < 0.05). It was observed no statistically significant difference at 8 mm (p > 0.05).

CONCLUSION

No technique could completely fill in root canal. Regarding the coronal part, all techniques can be used for more effective filling as long as a good condensation is achieved. The use of a plugger with an optimal size according to the localisation of root canal curvature and the choice of a heat-resistant root canal sealer affects the success of the treatment in the thermoplastic techniques.

Evaluation of 3 Different Retreatment Techniques in Maxillary Molar Teeth by Using Micro-computed Tomography

INTRODUCTION

Nonsurgical retreatment procedure involves the complete removal of the previous filling material to allow thorough instrumentation, disinfection, and refilling of root canal system. We aimed to determine the residuals of the root-filling material by using 3 different retreatment techniques with the aid of micro-computed tomography.

METHODS

Thirty extracted human maxillary molar teeth were included. All root canals were also obturated with F2 ProTaper single cones and AH Plus sealer. The following retreatment techniques were performed: group 1, ProTaper retreatment files; group 2, Mtwo retreatment files; and group 3, ProFile files. For the assessment of residual filling material, preoperative and postoperative micro-computed tomography scans were compared with each other, and the working time was recorded. One-way analysis of variance was used to analyze the differences between the groups. The significance level was set at P < .05.

RESULTS

None of the retreatment techniques were capable of removing the whole filling material. The percentages of the residual filling materials for groups 1, 2, and 3 were 34.45, 45.43, and 23.63, respectively. There was a statistically significant difference between groups 2 and 3 (P < .05). ProTaper and ProFile instruments required less time for the removal of filling materials when compared with Mtwo instrument.

CONCLUSIONS

ProFile files revealed the best results for endodontic retreatment in terms of both removing capacity and time requirement.

In vitro comparison of gutta-percha-filled area percentages in root canals instrumented and obturated with different techniques

Purpose:

To evaluate the efficacy of different obturation techniques in root canals instrumented either by hand or rotary instruments with regard to the percentage of gutta- percha-filled area (PGFA).

Materials and Methods:

One hundred and sixty extracted mandibular premolars with single, straight root canals were studied. Root canals were prepared to an apical size of 30 by hand with a modified crown-down technique or the ProTaper and HEROShaper systems. Teeth were divided into eight groups (n=20) according to the following instrumentation and obturation techniques: G1: Hand files+lateral condensation (LC), G2: Hand files+Thermafil, G3: ProTaper+LC, G4: ProTaper+single-cone, G5: ProTaper+ProTaper-Obturator, G6: HEROShaper+LC, G7: HEROShaper+single-cone, G8: HEROShaper+HEROfill. Horizontal sections were cut at 1, 3, 5, 7, 9, 11 and 13 mm from the apical foramen. A total of 1120 sections obtained were digitally photographed under a stereomicroscope set at 48X magnification. The cross-sectional area of the canal and the gutta-percha was measured by digital image analysis and the PGFA was calculated for each section.

Results:

The mean of the PGFA in Thermafil (G2), ProTaper-Obturator (G5) and HEROfill (G8) groups was significantly higher than the other groups. In G3 and G4, PGFA showed no significant difference in the apical segments whereas PGFA was significantly higher at the middle and coronal segments in G3. In G6 and G7, PGFA showed no significant difference in the apical and middle segments whereas PGFA was significantly higher at the coronal segments in G6.

Conclusion:

The carrier-based gutta-percha obturation systems revealed significantly higher PGFA in comparison to single-cone and lateral condensation techniques.

Influence of Post Space Preparation on the Apical Leakage of Calamus, Single-Cone and Cold Lateral Condensation Obturation Techniques: A Computerized Fluid Filtration Study

PURPOSE

Apical microleakage between the root canal and periapical tissues is considered a common cause of endodontic failure. The aim of this study was to evaluate the apical microleakage of various obturation techniques after immediate post space preparations with different drills.

MATERIALS AND METHODS

One hundred twenty human single-rooted teeth were selected for this study. The coronal portions were removed to achieve a uniform length of 15 mm. All root canals were instrumented with ProTaper Next rotary files using crown-down technique. The 120 roots were randomly assigned to 3 experimental groups according to obturation technique (n = 40). The root canals were obturated with lateral condensation in group 1, single-cone technique in group 2, and Calamus 3D obturation system in group 3. Each group was divided into two subgroups (n = 20) according to drill types (Gates Glidden and Peeso drills) leaving 5 mm of apical gutta-percha. The apical microleakage was measured using the computerized fluid filtration meter method. The results were evaluated using Kruskal-Wallis test with Bonferroni Corrected Mann-Whitney U multiple comparison post hoc tests.

RESULTS

There was no statistically significant difference between obturation techniques after post space preparation with Peeso drills (p > 0.05). In Gates Glidden drill groups, single-cone technique demonstrated higher leakage (0.0051 ± 0.0037 μl x min^-1 × cmH₂ O^-1 ) than Calamus techniques (0.0019 ± 0.0012 μl x min^-1 × cmH₂ O^-1 ) (p < 0.017).

CONCLUSIONS

Gates Glidden drills caused the highest apical leakage in teeth obturated with single-cone technique.

Radiological, stereological, and microscopic evaluation of the quality of canal fillings in oval-shaped root canals prepared with self-adjusting file

The aim of this study was to evaluate the quality of the canal fillings performed by thermoplastic technique (Herofill) and cold lateral condensation (CLC) techniques in oval shaped canals following self-adjusting file (SAF) preparation using radiological, stereological, and microscopic evaluation methods. Twelve pairs of oval-shaped root canals were prepared with SAF and filled using CLC (n = 12) or the Herofill system (n = 12). The quality of the root canal filling was evaluated by (i) scoring bidirectional storage phosphor plate images, (ii) stereological (volumetric) analysis of cone beam computerized tomography (CBCT) images, and (iii) microscopic analysis of the cross-sectioned area of the canal and gutta-percha via image analysis software. Chi-square test, t-test, and Mann-Whitney U-tests were used respectively (p < 0.05) for the aforementioned evaluations. 58.33% of the fillings (total n = 24) that were found to be sufficient in a bucco-lingual (BL) projection were considered insufficient in the mesio-distal (MD) projection according to radiological scoring. The difference in the findings between the two types of projections (BL and MD) was significant (p < 0.05). The results of the stereological evaluation of CBCT images and image analysis of cross-sections showed no statistically significant difference between the CLC and Herofill (p > 0.05). Herofill was not superior to cold lateral compaction. Stereology can be used to obtain unbiased information about the volume of root canal fillings. Both filling techniques failed to achieve the desirable goal of 0% empty volume in all of the cases and all evaluation systems confirmed this result. SCANNING 38:427-433, 2016. © 2015 Wiley Periodicals, Inc.

Technical quality of a matching-taper single-cone filling technique following rotary instrumentation compared with lateral compaction after manual preparation: a retrospective study

OBJECTIVES

The objectives of the study were to evaluate the radiographic technical quality of root canal treatment before and after the implementation of a nickel-titanium rotary (NiTiR) preparation followed by a matching-taper single-cone (mSC) obturation and to detect the procedural errors associated with this technique.

MATERIALS AND METHODS

A random sample of 535 patients received root canal treatment at the Department of Conservative Dentistry and Periodontology at the University of Würzburg: 254 teeth were treated in 2002-2003 by using stainless steel instruments (SSI) for preparation and a lateral compaction (LC) technique (classic group (CG)). Two hundred eighty-one teeth were root filled in 2012-2013 employing NiTiR instruments for the root canal shaping and a mSC technique (advanced group (AG)). The quality assessments were based on the radiographic criteria of the European Society of Endodontology. The presence of voids was recorded separately for the apical, central and cervical thirds of the root canals. Procedural errors, such as ledges, apical transportations, perforations and fractured instruments, were detected. The root canal fillings in the CG and AG were compared using chi-squared and Fisher's exact tests. Multivariable logistic regression was performed to investigate the association between the independent variables (patient age, tooth type and type of treatment) and the dependent variables (density and length).

RESULTS

Adequate length was achieved significantly more often in the AG compared to the CG for molars (p = 0.017), mandibular teeth (p = 0.013) and primary root canal treatments (p = 0.024). No significant difference was detected between the AG and CG regarding adequate length in general (p = 0.051) or adequate overall quality of root canal filling (p = 0.1). In the AG, a significant decrease in procedural errors was evident (p = 0.019) and decreases in the densities of the root canal fillings in the cervical (p = 0.01) and central (p = 0.01) thirds of the root canals were also observed. Moreover, root canals in elderly patients exhibited fewer voids (p = 0.009).

CONCLUSIONS

Rotary root canal preparation followed by a matching-taper single-cone filling technique provides a reliable shaping of the root canal, with fewer procedural errors and a more acceptable filling quality in terms of length and homogeneity in the apical third. Less favourable results were achieved in the central and cervical parts of the root canals.

CLINICAL RELEVANCE

The matching-taper single-cone technique seems to effectively obturate well-tapered root canals after adequate rotary instrumentation. Irregularly shaped canals require additional lateral or warm vertical condensation to avoid voids.

Apical filling characteristics of carrier-based techniques vs. single cone technique in curved root canals

OBJECTIVES

In this in vitro study, we assessed filling characteristics (adaptation, homogeneity, sealer percentage, position of the carrier) of warm and cold obturation methods in curved root canals.

MATERIALS AND METHODS

A reciprocating method was used to prepare 90 curved roots (25 ° average curvature) to an apical size of 25.08. They were then obturated with either (A) Guttafusion (VDW, Munich, Germany), (B) Thermafil (Maillefer, Ballaigues, Switzerland) or (C) single cone technique using 25.08 gutta-percha (VDW) and sealer (2Seal easymix) (n = 30 each group). Five sections in 1-mm steps were obtained from each root, beginning 1 mm short of the apex. The percentage of voids in contact with root canal walls (PVO), the proportion of voids per area (PVA) and the percentage of sealer per area (PSA) were measured.

RESULTS

Little to no differences between Guttafusion and Thermafil were seen in curved root canals with respect to adaptation and homogeneity in the apical region. Both methods showed significantly better adaptation and homogeneity than the single cone technique. The proportion of sealer was significantly greater when roots were obturated with Guttafusion than with Thermafil, but both warm obturation techniques had significantly smaller sealer areas than the single cone technique.

CONCLUSIONS

Compared to the single cone technique, a more favourable root canal filling with less sealer could be expected from both warm obturation techniques in curved root canals.

CLINICAL RELEVANCE

The easier-to-handle Guttafusion leads to comparable results as Thermafil in curved root canals.

Effect of education intervention on the quality and long-term outcomes of root canal treatment in general practice

AIM

To compare the technical quality and long-term outcomes of root canal treatment by general practitioners of a Swedish Public Dental Service, before and after an endodontic education including Ni-Ti rotary technique (NiTiR).

METHODOLOGY

A random sample was compiled, comprising one root filled tooth from each of 830 patients, treated by 69 general practitioners participating in the education: 414 teeth root filled in 2002, pre-education, using primarily stainless steel instrumentation and filling by lateral compaction, and 416 teeth root filled post-education (2005), using mainly NiTiR and single-cone obturation. Follow-up radiographs taken in 2009 were evaluated alongside immediate post-filling radiographs from 2002 to 2005. The density and length of the root fillings were registered. Periapical status was assessed by the Periapical Index (PAI), using two definitions of disease: apical periodontitis (AP) (PAI 3 + 4 + 5) and definite AP (PAI 4 + 5). Tooth survival was registered. Root fillings pre- and post-education were compared using chi-square and Fisher's exact tests. Crude extraction rates per 100 years were calculated for comparison of tooth survival. Explanatory variables (type of tooth, root filling quality, periapical status, marginal bone loss, type and quality of coronal restoration) in relation to the dependent variable (AP at follow-up) were analysed by multivariable logistic regression.

RESULTS

Follow-up data were available for 229 (55%) of teeth treated pre- and 288 (69%) treated post-education: both tooth survival (P < 0.001) and root filling quality were significantly higher (P < 0.001) in the latter. However, there was no corresponding improvement in periapical status. Both pre- and post-education, root fillings with definite AP on completion of treatment had significantly higher odds of AP or definite AP at follow-up. For teeth treated post-education, inadequate root filling quality was significantly associated with AP at follow-up.

CONCLUSIONS

Despite a higher tooth survival rate and a significant improvement in technical quality of root fillings after the education, there was no corresponding improvement in periapical status.

Calcium Hydroxide Dressing Influences the Obturation of Simulated Lateral Canals

AIM

The aim of this study was to investigate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques.

MATERIALS AND METHODS

Sixty single-root-premolars were instrumented. Simulated lateral canals were drilled on each third of the roots. The teeth were divided into four groups: no dressing and obturation by lateral condensation technique (G1), dressing with calcium hydroxide and obturation by lateral condensation technique (G2), no dressing and obturation by hybrid technique (G3) and, dressing with calcium hydroxide and obturation by hybrid technique (G4). The teeth were maintained at 37°C in 100% humidity for 7 days, and obturation techniques were performed. Radiographs were taken and filled or unfilled lateral canals were counted. Data were analyzed using analysis of variance (ANOVA) followed by Tukey's test (a = 5%).

RESULTS

The hybrid technique filled large number of lateral canals as compared to lateral condensation technique, regardless the use of intracanal medication (p < 0.05). Calcium hydroxide decreased the number of lateral canals filled for both lateral and hybrid techniques (p < 0.05). Significant differences were observed when comparing the number of filled and unfilled lateral canals in the same root third of each group (p < 0.05).

CONCLUSION

Regardless the obturation technique, calcium hydroxide dressing reduced the penetration of filling material in simulated lateral canals.

CLINICAL SIGNIFICANCE

The persistence of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, possibly representing a potential cause of failure in the future.

Filling of simulated lateral canals with gutta-percha or thermoplastic polymer by warm vertical compaction

The aim of this study was to evaluate the ability of gutta-percha and a thermoplastic synthetic polymer (Resilon) to fill simulated lateral canals, using warm vertical compaction. Forty-five single-rooted human teeth were prepared using the rotary crown-down technique. Artificial lateral canals were made at 2, 5, and 8 mm from the working length (WL) in each root. The specimens were divided into three groups (n = 15), according to the filling material: Dentsply gutta-percha (GD), Odous gutta-percha (GO), and Resilon cones (RE). The root canals were obturated using warm vertical compaction, without endodontic sealer. The specimens were subjected to a tooth decalcification and clearing procedure. Filling of the lateral canals was analyzed by digital radiography and digital photographs, using the Image Tool software. The data were subjected to the Kruskal-Wallis and Dunn tests at 5% significance. RE had the best filling ability in all root thirds (p < 0.05), with similar results for GO in the coronal third. In the middle and apical thirds, GD and GO had similar results (p > 0.05). Resilon may be used as an alternative to gutta-percha as a solid core filling material for use with the warm vertical compaction technique. The study findings point to the potential benefit of the warm vertical compaction technique for filling lateral canals, and the study provides further information about using Resilon and gutta-percha as materials for the warm vertical compaction technique.

Comparison of single cone obturation performance of different novel nickel-titanium rotary systems

OBJECTIVES

The purpose of this study was to compare several different single-cone obturations in the gutta-percha-filled areas (PGFA), sealer-filled areas (PSFA) and voids, also determining the volumetric characteristics of the tested cones.

MATERIALS AND METHODS

Curved mesial roots of 120 mandibular molars were instrumented using several different systems (ProTaper Next, Twisted File Adaptive, OneShape, ProTaper Universal, WaveOne and Reciproc) and filled with corresponding single cones. The teeth were then sectioned horizontally at 2, 4, 6 and 8 mm from the apex. The area values of each section were calculated and converted to percentages (PGFA, PSFA and voids) of the total area. To determine volumetric characteristics of the tested cones, 20 gutta-percha points of each tested group were scanned with CBCT using the same parameters.

RESULTS

The ProTaper Next and WaveOne groups presented the most PGFA and least PSFA. The Twisted File Adaptive group presented the least PGFA and most PSFA (p < 0.05) and the least gutta-percha volume.

CONCLUSIONS

The Twisted File Adaptive system matched cones had the least volume and the least PGFA in severely curved mesiobuccal canals of mandibular first molars. Single matched cones volume varied.

Use of fluid filtration method to evaluate the effect of master cone size on the apical seal of severely curved root canals

The apical third of most root canals shows some degree of curvature, which is important in cleaning/shaping and obturation during root canal treatment. The present study evaluated the effect of master cone size on the apical seal of severely curved root canals. Thirty-eight mesial roots of human mandibular first molars were prepared using the crown-down technique. All samples were mature roots with closed apices, had no carious lesions or resorption, and had a canal curvature of > 45º to 60º. Two samples were used as a negative and positive control to evaluate the fluid filtration equipment, and the remaining 36 samples were equally divided into groups A, B, and C based on master cone size, namely, gutta-percha #20, #25, and #30, respectively. The fluid filtration method was used to evaluate microleakage. No significant difference in microleakage was observed among groups (P = 0.31). In conclusion, an increase in master cone size up to #30 does not significantly influence apical microleakage.

Percentage of gutta-percha-filled areas in canals instrumented with nickel-titanium systems and obturated with matching single cones

INTRODUCTION

The purpose of this study was to compare different single-cone obturation techniques in terms of the percentage of gutta-percha-filled areas (PGFA), sealer-filled areas (PSFA), and voids.

METHODS

Sixty extracted mandibular incisors with straight canals were allocated into 6 groups: (A) FlexMaster, (B) Mtwo, (C) ProTaper, (D) Reciproc, (E) WaveOne, and (F) control. In groups A-E, obturation was performed by using matching single-cone gutta-percha. In group F (control), manual instrumentation and obturation were performed by using cold lateral compaction with standardized gutta-percha cones. The teeth were sectioned at 2, 4, 6, and 8 mm from the apex. The total area of each canal segment was measured, and the areas were converted to PGFA, PSFA, and percentage of voids. Data were subjected to the Kruskal-Wallis and post hoc Dunn test.

RESULTS

At the 2-mm level, group B produced significantly higher PGFA than all other groups, whereas group B produced significantly higher PGFA than groups C, D, and E (P < .05). At the 4-mm level, groups A and B produced significantly higher PGFA than all other groups, whereas group F produced significantly higher PGFA and lower PSFA than groups C, D, and E (P < .05). At the 6-mm level, group F produced significantly higher PGFA and lower PSFA (P < .05) than all other groups, whereas groups A and B produced significantly higher PGFA and lower PSFA than groups C, D, and E (P < .05). At the 8-mm level, group F produced significantly higher PGFA and lower PSFA (P < .05) than all other groups.

CONCLUSIONS

Under the conditions of this study, lateral compaction and single-cone techniques that used constant tapered gutta-percha (FlexMaster, Mtwo) produced higher PGFA at the apical levels than variable tapered single-cone gutta-percha (ProTaper, Reciproc, WaveOne).

A clinical trial of cold lateral compaction with Obtura II technique in root canal obturation

INTRODUCTION

The purpose of obturation of the prepared root canal space is to prevent coronal leakage and bacterial contamination and to seal the apex from the periapical tissue fluids. Cold lateral technique has been considered to be a gold standard, however considering its limitations various thermoplasticized gutta-percha techniques have been recommended. This study compares radiographic quality of obturation in molar teeth, obturated with cold lateral condensation and thermoplasticized injectable gutta-percha technique (Obtura II system).

MATERIALS AND METHODS

Sixty patients were equally divided into two groups, Group A obturated with Cold lateral condensation technique and group B with Obtura II. Periapical radiographs were obtained immediately after the obturation using paralleling device method. The radiographs were examined by an observer, who was blinded to the group allocation. Data was compared using χ(2) (Chi square) test and Independent sample t test was used to compare the mean ages.

RESULTS

Both groups were comparable in all respects such as tooth type, preoperative diagnosis and preoperative pain (P>0.05); however, more pre-operative radiolucency cases were allocated to Obtura II (P<0.05). There was no difference between the two groups, both in terms of postoperative voids as well as apical termination of the obturation (P>0.05).

CONCLUSION

Within the limitations of the study, it was found that statistically there was no significant difference between cold lateral and obtura II technique, in terms of post obturation voids and apical termination, as observed in radiographs.