Microleakage of Single-Cone Gutta-Percha Obturation Technique in Combination with Different Types of Sealers

Comparative Evaluation of Different Obturation Techniques for Root Canal Filling of Permanent Teeth: An In-Vitro Study

INTRODUCTION

Achieving success in root canal (RC) therapy relies on three key components: comprehensive cleaning of the canal, efficient disinfection, and proper filling of the canal space. The present study aimed to compare the efficacy of four obturation techniques: single cone (SC), GuttaCore (GC), cold lateral condensation (LC), and C Point system for RC filling of permanent teeth.

MATERIALS AND METHODS

76 extracted human mandibular first premolars were divided into four groups, with 19 teeth in each group (group A, obturation with SC technique; group B, obturation with GC; group C, obturation with LC; and group D, obturation with C Point system). The samples were marked at 4 mm and 8 mm from the root apex using a marker and calliper, sectioned horizontally, and analyzed under a stereomicroscope at 20x magnification. The mean percentage (%) of gutta-percha (GP)-filled area was compared using a two-way analysis of variance (ANOVA), followed by the Bonferroni post-hoc test.

RESULTS

The mean percentage of GP-filled area at a distance of 4 mm from the apex was highest in group B (0.86±0.04; 95% CI: 0.845-0.881), followed by group D (0.70±0.07; 95% CI: 0.664-0.736), group A (0.61±0.05; 95% CI: 0.595-0.642), and least in group C (0.58±0.09; 95% CI: 0.543-0.627), and the difference was statistically significant (p≤0.05). The post-hoc pairwise comparison of groups at 4 mm revealed that there were statistically significant differences between group D and groups B, C, and A (p ≤ 0.001). The mean percentage of the GP area at a distance of 8 mm from the apex was highest in group B (0.81±0.10; 95% CI: 0.761-0.861), followed by group D (0.75±0.07; 95% CI: 0.725-0.792), group A (0.69±0.07; 95% CI: 0.658-0.729), and lowest in group C (0.65±0.10; 95% CI: 0.607-0.709), and this difference was statistically significant (p≤0.05). Post-hoc pairwise comparison of groups at 8 mm revealed that there was a statistically significant difference between groups D and C (p=0.006), whereas no statistically significant differences were noted between groups D and B (p=0.473). Furthermore, no statistically significant differences were noted between groups C and A at 4 mm and 8 mm (p>0.05).

CONCLUSION

Obturation with the GC system provided the best results in terms of the percentage of GP-filled area at 4 mm. However, at 8 mm from the apical region, both the GC and C Point systems provided similar results.

Effect of Obturation Techniques on the Quality of Root Canal Fillings: A Systematic Review and Meta-analysis of in Vitro Studies

Introduction

The current study aimed to compare the quality of root canal obturation performed with cold lateral condensation with other obturation techniques.

Materials and Methods

Diverse Search was conducted using six electronic/academic databases following PICOS (i.e. population, intervention, control, outcomes, and study design) strategy: (P) Extracted mature permanent teeth; (I) Obturation techniques except for cold lateral condensation; (C) Cold lateral condensation tyechnique; (O) Quality of root canal obturation; and (S) In vitro studies assessing parameters using micro-computed tomography. The statistical method used for the meta-analyses was the "inverse variance DerSimonian-Laird test". The heterogeneity data was calculated using the T2, Cochran Q test, and I2 statistics.

Results

Fifteen studies were included for the final analysis; one had a low risk of bias, eight a moderate risk, and six a high risk of bias. Ten studies were selected for meta-analyses; three studies comparing cold lateral condensation with carrier-based gutta-percha techniques [P=0.96; mean difference (MD)=-0.02; confidence interval (CI): (-0.77, 0.73); I2=21%]; three comparing cold lateral condensation with single-cone techniques [P=0.75; MD=-0.39; CI: (-2.77, 1.99); I2=92%]; two comparing cold lateral condensation and thermo-plasticized injectable techniques [P=0.37; MD=5.91; CI: (-7.13,18.94); I2=99%]; and five comparing cold lateral condensation with warm vertical condensation techniques [P<0.0001; MD=5.29; CI=(2.84, 7.74); I2=92%]. The overall effect reported significant results [P=0.0003; MD=2.69; CI=(1.23, 4.16); I2=96%]; favoring fewer voids and gaps for the other used obturation techniques.

Conclusions

Cold lateral condensation and single-cone techniques presented no statistical differences. Nonetheless, Warm vertical condensation technique had better results compared to cold lateral condensation.

Adaptation of a Single-Cone in Prepared Teeth with Two Reciprocating Systems

Introduction

This ex vivo study aimed to compare the adaptation of single gutta-percha cone in teeth prepared with the Wave One Gold and Reciproc Blue reciprocating systems through cone-beam computed tomography.

Materials and Methods

A total of 40 recently extracted mono radicular premolars were randomly assigned into two groups (n=20) corresponding to Reciproc Blue and Wave One Gold reciprocating systems and adapted to a single cone system. Each group was evaluated by cone-beam computed tomography at 1 mm, 2 mm and 4 mm from the apical foramen. We evaluated the number of walls adapted by the cone, quality of filling and the number of spaces between the filling and the walls of the root canal. The Mann-Whitney U and T-tests were employed to associate and compare both groups (P<0.05).

Results

At 1 mm in the lingual wall the Wave One Gold system did not adapt by 45% compared to 15% with Reciproc Blue (P<0.05). Likewise, the single-cone filling technique of the Reciproc Blue system showed better sealing quality obtaining an ideal category (75%) compared to Wave One Gold (40%) (P<0.05). The amount of space (mm) found between the cone and the filling walls was greater with Wave One Gold. However, these values were not statistically significant.

Conclusions

Based on this ex vivo study the better adaptation of root canals and ideal filling condition was more frequent with Reciproc Blue than Wave One Gold system, mainly at 1 mm from the radicular apex.

Comparison between immediate and delayed post space preparations: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis compared the effects of immediate and delayed post space preparation on apical sealing.

MATERIALS AND METHOD

Two independent authors conducted a systematic search (PubMed/Medline, Cochrane Library, and other databases, until February 2020) and a risk of bias evaluation. Only in vitro studies that compared the effects of immediate and delayed post space preparations on apical filling and adhesion of the post were eligible.

RESULT

Of the 742 articles retrieved, 32 were included. Most of the studies used single-rooted human teeth and rotary files for root canal preparation, a single-cone technique for the filling protocol, and rotary instruments for post space preparation. Various delayed preparation times were evaluated: 8-72 h, 5-30 days (mainly 7 days), and 4 months. In nine studies, the delayed groups showed more apical leakage, while four studies reported more leakage in the immediate groups; ten studies found no significant difference. One study found more bacterial penetration in the delayed group, whereas three studies showed no significant difference. One study reported more voids in the delayed group, while another found no such difference. Three studies showed better post-bond strength in the delayed group, one in the immediate group, whereas three found no significant difference in post-bond strength. Three studies employing varied sealers for root canal fillings were considered for meta-analysis. Two subgroup analyses were also performed (one concerning the use of resin-based sealers (AH Plus), another for zinc oxide-eugenol-based sealers). The results of the meta-analysis showed that a delayed post space preparation led to a significantly higher apical leakage than an immediate preparation (mean difference = 0.41 mm, confidence interval = 0.24-0.59, p < 0.001).

CONCLUSION

Delayed post space preparation seems to negatively influence apical sealing; however, further studies are needed to determine the influence of the timing of post space preparation on the other parameters.

CLINICAL RELEVANCE

Immediate post space preparation may be the safest clinical choice to prevent apical leakage.

Effect of Sodium Thiosulfate on Interfacial Adaptation and Penetration of an Epoxy Resin-Based Root Canal Sealer

Introduction

Our study evaluated the impact of sodium thiosulfate (ST) irrigation, subsequent to sodium hypochlorite (NaOCl) and just before root canal filling, on the filling quality (interfacial adaptation and penetration segment) of an epoxy resin-based root canal sealer.

Methods and Materials

Twenty single-rooted human teeth were prepared with the ProTaper system. The specimens were then divided into the following groups: 5.25% NaOCl irrigation (NaOCl group) and 5.25% NaOCl irrigation+0.5% sodium thiosulfate (NaOCl+ST group). The root canals were filled using single-cone technique with ProTaper F3 cones and AH-Plus sealer, labeled with rhodamine B dye to allow analysis under a confocal laser scanning microscopy (CLSM). All samples were sectioned at 2, 4, and 6 mm from the apex and prepared for CLSM analysis. The percentage of voids, gaps and dentinal sealer penetration segment of the canal were calculated at the apical, middle and coronal thirds. The non-parametric Mann-Whitney statistical test was used at 5% significance level.

Results

Higher percentage of gaps and voids were observed at all root thirds of the NaOCl group when compared to the NaOCl+ST group (P<0.05). There was a significant increase in the penetration segment of NaOCl+ST group at the coronal and middle root third when compared to the NaOCl group (P<0.05).

Conclusion

Our in vitro results showed that the use of ST as an antioxidant agent after NaOCl irrigation promoted a better interfacial adaptation and penetration of epoxy resin-based root canal fillings.

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.

Effect of obturation technique with immediate and delayed post space preparation on apical voids and bond strength of apical gutta-percha

Objective

The purpose of this study was to evaluate the effect of immediate and delayed post space preparation on the sealing ability of two root canal obturation techniques by using micro-computed tomography imaging and a push-out test.

Methods

The root canals of 40 human maxillary premolar teeth were instrumented and divided into four groups: (A) single cone (SC) followed by immediate post space preparation, (B) continuous wave of condensation (CWC) followed by immediate post space preparation, (C) SC followed by delayed post space preparation, and (D) CWC followed by delayed post space preparation. Micro-CT scans were performed for volumetric analysis of voids and filling materials in the apical 4-mm portion. A push-out test was performed, and failure modes (adhesive, cohesive, or mixed) were assessed. Data were analyzed using the Kruskal-Wallis test and one-way analysis of variance.

Results

No significant differences were observed among the four groups in terms of the percentage volume of voids of the apical 4 mm or the bond strength of apical gutta-percha.

Conclusions

The percentage volume of voids and bond strength of apical gutta-percha were similar and were not significantly influenced by the timing of post space preparation or the obturation technique.

Influence of size and insertion depth of irrigation needle on debris extrusion and sealer penetration

Objectives

To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM).

Materials and Methods

Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed.

Results

Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both).

Conclusions

Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.

Intra-manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometre

INTRODUCTION

Manufacturers offer gutta-percha (GP) cones matched with different sizes of endodontic files as an attempt to simplify the obturation process and create a tight seal in the canal. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different levels using laser micrometre.

METHODS AND MATERIALS

Twenty files and corresponding GP master cones of Reciproc R40 (40/0.06) (VDW, Munich, Germany), WaveOne Large(40/0.08)(Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo 40/0.06 (VDW, Munich, Germany) were examined using laser micrometre (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D₀, D₁, D₃ and D₆. The data was analysed using the independent t-test. The differences were considered at 0.05.

RESULTS

The diameter of GP master cones was significantly larger than that of the corresponding files at all levels in all brands. ProTaper GP diameter was closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, File=0.49).

CONCLUSION

Within the same manufacturer, GP cone diameters do not match the diameters of their corresponding files. Clinicians are advised to use a GP gauge to cut the tip so as to appropriate the diameter from a smaller sized GP cone.

Physical Properties and Chemical Characterization of Two Experimental Epoxy Resin Root Canal Sealers

Introduction:

The aim of this in vitro study was to evaluate the setting time, flow, film thickness, solubility, radiopacity and characterization analysis of three epoxy resin based sealers including two experimental sealers and AH-26.

Methods and Materials:

Five samples of each material were evaluated for setting time, flow, film thickness, solubility and radiopacity according to ISO 6876 Standard. Characterization of sealers was performed under the scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Statistical evaluation was performed using the Kruskal-Wallis test.

Results:

In this study, AH-26 showed more radiopacity and flow compared to two other experimental sealers (P<0.05). However, both sealers had lower setting time than AH-26 (P<0.05). No statistical differences were found regarding film thickness, solubility and radiopacity (P>0.05). The characterization analysis exhibited relatively similar microstructure of AH-26 sealer to the experimental root canal sealers.

Conclusion:

According to the result of this study, all tested root canal sealers had acceptable properties based on ISO 6876 standard criteria.

Comparative evaluation of apical microleakage in immediate and delayed postspace preparation using four different root canal sealers: An in vitro study

BACKGROUND

Endodontically treated teeth often lack sufficient support for a permanent restoration. During post space preparation, it is important not to disturb the integrity of the apical seal.

AIM

This study compared the effect of immediate versus delayed post space preparation on the apical seal using four different sealers.

MATERIALS AND METHODS

One hundred and thirty single rooted teeth were biomechanically prepared and obturated with single cone gutta-percha and 4 sealers: Endoflas FS, AH Plus, Gutta flow and MTA. Teeth were divided randomly into eight groups, post spaces were prepared using Gates Glidden drills immediately for group I, III, IV and VII. For groups II, IV, VI and VIII prepared after storage of the specimens in 100% humidity for one week. The samples were kept in methylene blue dye, centrifuged at 3000 rpm for 3 min sectioned and then measured under stereomicroscope for apical leakage.

STATISTICAL ANALYSIS

The data was analysed using one way ANOVA and post hoc Tukey test.

RESULTS

All the specimens showed dye leakage, and a statistically significant difference was seen among all the groups (P > 0.05) except Gutta flow.

CONCLUSION

Less leakage is seen when post space is prepared immediately.

To evaluate the influence of smear layer with different instruments and obturation methods on microleakage of root canal filled teeth: In vitro study

AIMS AND OBJECTIVES

The success of root canal treatment depends on proper debridement, instrumentation, proper accessibility, and proper restoration. The presence of a smear layer is considered to be a significant factor. This in vitro study was conducted to assess the effect of the presence/absence of a smear layer on the microleakage of root canal filled teeth using different instruments and obturation methods.

MATERIALS AND METHODS

One hundred extracted mandibular premolars with closed apices and single roots were chosen and then divided into six groups, A to F, consisting of 15 teeth each. The control group included 10 teeth; 5 positive and 5 negative. The teeth were decoronated at the cementoenamel junction. Groups A, B, C, and D were instrumented with engine-driven rotary Protaper NiTi files. Groups E and F were instrumented with conventional stainless steel hand files. Groups A, C, and E were flushed with 3 ml of 17% EDTA to remove the smear layer prior to obturation. All teeth were flushed with 5.25% sodium hypochlorite solution and obturated with AH-Plus sealer with lateral condensation technique for Groups C, D, E, F and with thermoplasticized gutta-percha technique for Groups A and B. Using an electrochemical technique, leakages in the obturated canals were assessed for 45 days. The results were tabulated using Student's t-test (paired and unpaired t-test) with the Statistical Package for the Social Sciences Software Version 21 (IBM Company, New York, USA).

RESULTS

Group A showed the lowest mean value at intervals of 10, 20, 30, and 45 days. There was no current flow in the negative controls during the test period. There was leakage in the positive controls within a few minutes of immersion.

CONCLUSION

The results showed that rotary instrumentation contributed toward an exceptional preparation of root canals compared to hand instrumentation. Elimination of the smear layer enhanced the resistance to microleakage; thermoplasticized gutta-percha obturation technique produced a better seal compared to the lateral condensation technique.