Apical microleakage after lateral condensation, hybrid gutta-percha condensation and Soft-Core obturation: an in vitro evaluation

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.

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 the Quality of Obturation with Obtura at Different Sizes of Apical Preparation Through Microleakage Testing

INTRODUCTION

Obturation of the root canal system is required to prevent recontamination of the root canal after cleaning and shaping procedures and to seal the root canal completely, both the apical and coronal avenues of potential leakage and to maintain the disinfected status.

AIM

The aim of this study was to determine the microleakage by dye leakage method at 1mm, 3mm and 5mm short of the apex with different sizes of apical preparation, obturated by Obtura.

MATERIALS AND METHODS

Sixty freshly extracted human single rooted teeth were randomly distributed into six equal groups. Group I (control group) was obturated by lateral compaction technique. Group II to VI were experimental groups (apical preparations done upto ISO sizes 20, 30, 40, 50 and 60 respectively), obturated by Obtura technique. After storing the samples at 100% humidity for seven days and one day in 2% methylene blue, the roots of the teeth were sectioned at 3mm short of the apex. They were observed under stereomicroscope at 20X magnification and the images were analysed for microleakage using the scoring criteria. The data obtained were analysed by One-way ANOVA followed by Tukey pair-wise multiple comparison test and p ≤ 0.05 was considered as the level of significance.

RESULTS

The lowest mean microleakage score was seen in Group VI (0) and the highest mean leakage score was seen in Group II (1.5). There was statistically significant difference between Group II and Group V (p = 0.044), Group II and Group VI (p = 0.013). There was no significant difference between all the other groups (p> 0.05).

CONCLUSION

Comparison of microleakage between different groups from ISO sizes 20-60 recommends a minimum apical preparation of ISO size 30.

A Comparative in Vitro Study of Apical Microleakage with Five Obturation Techniques: Lateral Condensation, Soft-Core®, Obtura II®, Guttaflow® and Resilon®

AIM

A comparison was made between the root canal lateral condensation technique and other condensation techniques in which physical (temperature: Soft-Core®, Obtura II®) or chemical changes (condensation: Guttaflow®, Resilon®) may affect the dimensional stability of obturation and thus favor apical microleakage.

MATERIALS AND METHODS

A total of 212 single-root teeth removed for orthodontic or periodontal reasons were randomized to 5 groups of 40 teeth each. Six samples were used as positive controls, and another 6 as negative controls. The teeth were worked with the Hero 642 system, and each group was obturated using a different technique: lateral condensation, Obtura II®, Soft-Core®, Guttaflow® or Resilon®. The samples were immersed in black ink, and after 72 hours the teeth were transparentized using the technique described by Robertson. Filtration of the ink was measured under the stereoscopic microscope. Analysis of variance and post-hoc testing were used for the statistical analysis.

RESULTS

The Soft-Core® obturated group showed significantly greater microleakage than the other groups, with no differences among the rest of the groups.

CONCLUSIONS

Under the conditions of this study, the teeth obturated with the Soft-Core® technique showed greater apical microleakage than the other systems.

Effect of various endodontic solutions on punch out strength of Resilon under cyclic loading

Background:

Before obturation, various endodontic solutions are used as a final rinse. These solutions might affect the bond strength of Resilon-Epiphany system. The aim of this study was to evaluate the effect of NaOCl (5.25%), chlorhexidine CHX (2%), EDTA solution (17%), and BioPure MTAD on push out bond strength of Resilon-Epiphany system.

Materials and Methods:

Seventy-five human premolar roots were prepared and divided on the basis of final endodontic solution rinse. The canals were obturated with Resilon-Epiphany system. All samples were restored using a fiber post system and indirect composite crown. The samples received 150 000 cycles of mechanical loading. Push out bond strength was performed in the apical third of root having Resilon obturation.

Results and Conclusions:

Different endodontic solutions tested, did not affected the push out bond strength of Resilon-Epiphany obturation system.

Assessment of the apical seal of root canals using different filling techniques

The aim of this study was to investigate the apical leakage of roots filled by three different gutta-percha techniques: lateral condensation, Tagger's hybrid and E&Q Master. Forty-two extracted single-rooted teeth were used. The coronal part of each tooth was removed and the root received biomechanical preparation using a 60-K file. The roots were randomly divided into three groups according to the technique of filling the root canal: Group I, lateral condensation; Group II, Tagger's hybrid; Group III, E&Q Master. The roots were submitted to dye leakage test with Rhodamine B for 7 days, using vacuum during the initial 30 min. The teeth were sectioned longitudinally and the leakage was measured in a linear fashion from apex to crown. Statistical analysis indicated that lateral condensation and E&Q Master techniques showed lower leakage than Tagger's technique (P = 0.0016). However, statistically no difference was found between lateral condensation and E&Q Master system techniques.

A l2-month longitudinal in vitro leakage study on a new silicon-based root canal filling material (Gutta-Flow)

OBJECTIVE

This study was performed to determine in vitro the short- and long-term sealing ability of a recently developed silicon-based root canal filling material (Gutta-Flow).

STUDY DESIGN

Sixty human upper central incisors were divided into 3 groups (n = 20). The root canals were instrumented and obturated with laterally compacted gutta-percha and AH26 sealer (group 1), continuous-wave thermal compaction (System B technique) and AH26 sealer (group 2), and Gutta-Flow technique (group 3). Leakage along entire root canal fillings was measured by the movement of an air bubble in a micropipette connected to the experimental root using a fluid-transport model. Short-term leakage measurements were carried out for 3 hours after 24 hours of equilibrium establishment. Leakage was measured again and at 3, 6, and 12 months after the initial measurement.

RESULTS

At the 3-hour measurement, no significant differences were found among the 3 experimental groups. Long-term leakage measurements showed that at 3 and 6 months no significant differences were existed between Gutta-Flow and the other 2 techniques. However, at 12 months, root canal fillings with Gutta-Flow leaked significantly less than fillings of lateral compaction and System B technique.

CONCLUSIONS

Gutta-Flow technique showed a similar sealing ability to either lateral compaction or System B technique. This comparison improved significantly over time. These findings may be related to the possible expanding capacity of the material and the partial dissolution of the sealer over time in the other 2 groups.

Comparison of 6 different gutta-percha techniques (part II): Thermafil, JS Quick-Fill, Soft Core, Microseal, System B, and lateral condensation

OBJECTIVES

In this in vitro study, the core-to-sealer ratios were calculated for 6 different gutta-percha techniques: Thermafil, JS Quick-Fill, Soft Core, Microseal, System B, and lateral condensation. The core consisted of gutta-percha or gutta-percha and carrier.

STUDY DESIGN

The sealer-to-core ratios for the Thermafil, JS Quick-Fill, System B, and lateral condensation techniques were published previously. In this study, the sealer-to-core ratio for Microseal and Soft Core techniques was investigated. For this purpose, 20 teeth filled by using the Soft Core or the Microseal technique were embedded in resin and sectioned horizontally at 1, 2, 3, and 4 mm from the anatomic apex. Photographs were taken of each section, and the total area of the canals filled with core material or sealer was calculated.

RESULTS

Once all results were compiled, it became clear that core techniques (Thermafil, JS Quick-Fill, and Soft Core) produced higher gutta-percha content than the Microseal, System B, and lateral condensation techniques (P <.05). The lateral condensation technique produced the least gutta-percha content (P <.05).

CONCLUSION

Thermafil, JS Quick-Fill, and Soft Core were found to be superior to the Microseal, System B, and lateral condensation techniques in terms of the gutta-percha-to-sealer ratio.

In vitro evaluation of apical microleakage following canal filling with a coated carrier system compared with lateral and thermomechanical Gutta-Percha condensation techniques

AIM

The apical sealing ability of a coated carrier system was evaluated in extracted human teeth and compared with lateral and thermomechanical condensation techniques using dye penetration.

METHODOLOGY

Sixty-four extracted single-rooted teeth were instrumented to an apical size 30 using 4% taper Hero 642 trade mark instruments (Micromega, Besançon, France). The sample was divided into three experimental groups. Twenty teeth were randomly obturated with lateral condensation, 20 with thermomechanical compaction and 20 teeth with the Herofill trade mark Soft-Core system. Four teeth were used as positive and negative controls. The teeth were covered with nail varnish up to 2 mm from the apical foramen and immersed in a 2% aqueous methylene blue dye solution for 1 week and then washed, dehydrated and embedded in resin. The apical 1 mm of each tooth was removed to reveal the apical limit of the preparation. Transverse sections of the teeth were taken at 500, 1000 and 1500 micro m from this point and evaluated for apical leakage. Significant differences between the preparations were analysed with a semiautomatic analyser and the ratio of the dye-penetrated surface to the total dentinal surface was calculated.

RESULTS

Statistical analysis of the results demonstrated significantly less leakage for the Herofill trade mark Soft-Core system compared to lateral condensation in terms of total mean dentinal surface and at the 500 micro m level. No other differences were noted between Herofill trade mark Soft-Core and thermomechanical or lateral condensation, either for the total mean value or at each level.

CONCLUSIONS

The Herofill trade mark Soft-Core system was a reliable obturation system in the apical portion and compared favourably with other gutta-percha filling techniques.

A preliminary analysis of the morphology of lateral canals after root canal filling using a tooth-clearing technique

AIM

This study used a modified tooth-clearing technique to allow observation of accessory canals following filling with a warm gutta-percha technique and one of two endodontic cements.

METHODOLOGY

Ten extracted human maxillary molars with three roots were selected and divided into two equal groups of five teeth. Each group had 15 canals. Root canal preparation was performed with a modified double flared technique; irrigation with 5% NaOCl and lubrication with RC-Prep were used. The canals were then filled with gutta-percha and cement utilizing a warm vertical condensation technique in the apical third followed by thermo-mechanical compaction in the middle and coronal thirds. Pulp Canal Sealer or AH-Plus were used in the experimental groups. The teeth were demineralized with a modified buffered acid solution, cleared in methylsalicylate and examined under a stereomicroscope. Accessory canals were evaluated in the apical, middle and coronal thirds of each root canal and categorized as narrow or wide, following observation on four surfaces. The depth of penetration of gutta-percha and cement into lateral canals was scored using a 5-point system.

RESULTS

Complete transparency of the roots was achieved. Accessory canals were detected in all specimens. In coronal ramifications, gutta-percha filled the empty spaces (coronal thirds, grades 3 and 4: 70.9% in AH-Plus group and 68.8% in Pulp Canal Sealer group). In the apical accessory canals, gutta-percha entered less frequently (apical thirds, grades 3 and 4: 17.9% in the AH-Plus group and 3.2% in the Pulp Canal Sealer group); cement without gutta-percha (grades 1 and 2) was present in 55.5% in the AH-Plus group and 38.7% of the Pulp Canal Sealer group. Analysis showed that AH-Plus cement resulted in significantly greater filling of the apical accessory canals compared to Pulp Canal Sealer.

CONCLUSIONS

The modified tooth-clearing technique allowed observation of fine morphological details in all specimens. Effective gutta-percha filling was evident in most of the wide coronal lateral canals whilst the apical narrow ramifications were often incompletely filled by cement. Overall AH-Plus demonstrated better diffusion into lateral accessory canals compared to Pulp Canal Sealer.

The long-term sealing ability of an epoxy resin root canal sealer used with five gutta percha obturation techniques

AIM

The aim of the present study was to evaluate the long-term sealing ability (both apical and coronal) of an epoxy resin root canal sealer (AH26) when used with different gutta-percha obturation techniques.

METHODOLOGY

Straight single-rooted teeth with mature apices were divided into 10 groups of 75 teeth and one group of 40 control teeth. Root canals were prepared according to the crown-down/step-back technique and using both 2.5% sodium hypochlorite and an EDTA paste. Root canals were obturated using cold lateral condensation, warm vertical condensation and hybrid condensation of gutta-percha; and with Thermafil and Soft-Core obturators. AH26 was used as the sealer in all cases. After root canal filling, each group was divided into five individual groups of 15 teeth. The first group of 15 teeth was kept for 1 day, the second for 1 week, the third for 4 months, the fourth for 6 months and the fifth for 12 months at 37 degrees C in vacutainers in 80% relative humidity. The teeth were immersed in India ink for 90 h, each root was split and sectioned longitudinally, and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification.

RESULTS

Leakage occurred whatever filling technique was combined with AH26. The number of teeth with gross leakage increased with time up to 4 months, but did not appear to increase between 6 and 12 months storage. The degree of apical leakage and the number of leaking teeth in the Soft-Core obturator groups was significantly higher than all four other gutta-percha obturation techniques. Up to 4 months the degree of coronal leakage and the number of leaking teeth in the Thermafil groups was significantly higher than the other gutta-percha obturation techniques, except for Soft-Core. In the Soft-Core obturator groups the degree of coronal leakage and the number of leaking teeth was significantly higher than the other gutta-percha obturation techniques, except for Thermafil at all evaluation times.

CONCLUSION

The hybrid gutta-percha condensation technique was superior to the other four obturation techniques in respect of apical leakage. Coronal leakage was significantly greater during the first 4 months for the Thermafil system as compared to the three condensation techniques; coronal leakage was significantly greater at all time periods for the Soft-Core system. There were no significant differences between the Thermafil and the Soft-core system.