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

A Comparative Evaluation of Micro-Leakage in Fiber Post Luted and Core Buildup Performed with Two Different Resin Cements: An In vitro Study

Objective

To compare the micro-leakages of fiber post luted and core buildup performed with ParaCore (Coltene) and LuxaCore (DMG) resin cement.

Materials and Methods

Thirty-six single-rooted teeth were selected and treated with root canal treatment and fiber post cementation with two types of resin cement (LuxaCore and ParaCore). Samples were exposed to 500 cycles of thermocycling, immersed in 2% methylene dye and centrifuged and sectioned longitudinally, and checked under a stereomicroscope.

Results

LuxaCore and ParaCore showed a mean of 0.39250 mm and 0.47500 mm micro-leakage, respectively.

Conclusion

There was a statistically non-significant difference seen with group 3 (LuxaCore) versus group 4 (ParaCore) (P > 0.05).

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.

Coronal and apical leakage among five endodontic sealers

PURPOSE

The aim of this study was to use dye penetration to measure apical and coronal leakage simultaneously in single-canal teeth that had been treated endodontically using a single-cone obturation technique.

METHODS

One hundred single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size-X5 (50/.06), then randomly assigned to five sealer groups for single-cone gutta-percha obturation. The teeth were soaked in 0.6% rhodamine B at 37°C for seven days, then the roots were ground mesiodistally and the maximum apical and coronal dye penetration was measured. Differences in leakage among the sealer groups were examined using the Kruskal-Wallis test. Pairwise comparisons were made using the Mann-Whitney test with Bonferroni correction.

RESULTS

The mean values (mm) of dye penetration for AH Plus, Pulp Canal Sealer, NeoSEALER Flo, EndoSequence BC, and Super-Bond RC Sealer were 0.200, 0.300, 0.675, 0.850, and 0.900 apically, whereas 1.675, 2.075, 4.800, 6.500, and 4.125 coronally. Pairwise comparisons showed significant apical differences between AH Plus/Super-Bond RC Sealer (P = 0.047) and significant coronal differences between AH Plus/NeoSEALER Flo (P = 0.001), AH Plus/EndoSequence BC (P < 0.01), AH Plus/Super-Bond RC Sealer (P < 0.01), Pulp Canal Sealer/NeoSEALER Flo (P = 0.010), Pulp Canal Sealer/EndoSequence BC (P < 0.01), and Pulp Canal Sealer/Super-Bond RC Sealer (P < 0.01).

CONCLUSION

Coronal leakage was worse than apical leakage for all sealers. AH Plus exhibited the least leakage apically and coronally; Super-Bond RC Sealer showed the most leakage apically, and EndoSequence BC showed the most leakage coronally.

Comparison of Coronal Leakage in Tooth Preparation with Two Single File Systems and Three Obturation Techniques

Aims and Objectives:

Root canal preparation and obturation are of great importance in endodontics. Its purpose is to eliminate pulpal and periradicular disease. The aim of this study was to compare coronal bacterial microleakage in prepared root canals using Neoniti A1 and Reciproc files that obturated with lateral compaction, single cone gutta-percha, and hybrid (tapered cone/lateral compaction) methods.

Materials and Methods:

In this ex vivo study, a total of 110 single-rooted mandibular first premolars were choose and randomly divided into two study groups A and B (each 45) that one group was prepared with Reciproc and another with Neoniti A1 and negative and positive control groups (each 10). Each group divided into three subgroups of 15 each and obturated using a single cone, lateral compaction, and hybrid (tapered cone/lateral compaction) techniques. For evaluation of coronal leakage, “two-chamber setup” was used. The solution of enterococcus faecalis culture was injected in the upper chamber and incubated. If the bacteria pass through the canal and obturation materials, the lower chamber becomes turbid. TSB medium in the lower chamber (apex) were investigated every day in terms of occurrence of turbidity, and the duration of occurrence of leakage was recorded. The data were analyzed using Chi-square test.

Results:

Data analysis showed that in each group the difference in percentages between subgroups was statistically significant (P = 0.003). So that the highest and the lowest amount of leakage in both groups were related to lateral compaction and hybrid techniques, respectively.

Conclusion:

Under the conditions of this study, independent of the instrument used for canal preparation, hybrid method and then single-cone technique, however, were more effective in the prevention of coronal leakage than lateral condensation technique.

Antibacterial Activity of MTA Fillapex and AH 26 Root Canal Sealers at Different Time Intervals

Introduction:

The main goal of endodontic treatment is elimination of bacteria and their by-products from infected root canals. This study compared the antibacterial effect of two different sealers, AH 26 and MTA Fillapex, on 4 microorganisms 24, 48 and 72 h and 7 days after mixing.

Methods and Materials:

The microorganisms used in this study consisted of Lactobacillus acidophilus (ATCC 4356), Lactobacillus casei (ATCC 39392), Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 29212). This test is based on the growth of bacteria and turbidity measurement technique using a spectrophotometer, and direct contact was conducted. Multiple comparisons were carried out using repeated-measures ANOVA followed by Tukey’s test and student’s t-test. The level of significance was set at 0.05.

Results:

The antibacterial activity in the indirect technique was more than the technique with both sealers. In the direct technique the antibacterial activity on all microorganisms were lower for MTA Fillapex sealer. In the indirect technique, both sealers exhibited similar antibacterial properties.

Conclusion:

The antibacterial effect of MTA Fillapex sealer was significantly less than that of AH 26 sealer in the direct technique. The antibacterial effects of both sealers were similar in the indirect technique.

Evaluation of Coronal Leakage Following Different Obturation Techniques and in-vitro Evalution Using Methylene Blue Dye Preparation

INTRODUCTION

Coronal and apical leakage still remains one of the most important cause for endodontic failure in spite of the presence of advanced endodontic materials. The cause may attribute to different filling techniques, physical and chemical properties of sealers and presence or absence of smear layer assessment of coronal or apical leakage is used as a research method to compare the sealing ability of different techniques and endodontic materials.

AIM

To compare the coronal bacterial leakage using methylene blue in four different obturation techniques after protaper hand instrumentation.

MATERIALS AND METHODS

Ninety extracted single-rooted teeth were instrumented to an apical preparation size F3 Protaper hand files. Twenty teeth were randomly obturated with lateral compaction, 20 with vertical compaction, 20 with combination of vertical and lateral compaction and 20 with Thermafil. Ten teeth were used for positive and negative controls (five teeth in each group). Teeth were kept in 100% humidity for 90 days, and then subjected coronally to Proteus vulgaris for 21 days to assess bacterial leakage. After bacterial challenge, methylene blue was placed coronally for another 21 days, and then scoring was done according to depth of dye leakage. Chi-square test was done for statistical analysis.

RESULTS

Leakage as observed with combination of vertical and lateral compaction was significantly less than vertical compaction, lateral compaction and thermafil carriers during bacterial challenge. However, when dye was used it also showed statistically significant results with thermafil carriers showing the least leakage in comparison to vertical condensation, lateral condensation and combined groups.

CONCLUSION

The study concludes that two different methods i.e. bacterial and dye leakage revealed considerable variation on the same substrate Thus, due to the presence of variability among the results obtained by two different analytical methods used in the present study, the study emphasizes the need for standardization of methods as the lack of standardization hinders the comparison of different endodontic filling techniques.

In vitro evaluation of carrier based obturation technique: a CBCT study

AIM

The goal of the study was to compare the ability of two different carrier based obturation (CBO) techniques to reach working length and fill in three-dimensions root canal systems, by using CBCT.

MATERIALS AND METHODS

Twenty-six extracted molars were scanned with CBCT and 40 curved canals were selected (between 30° and 90°) and divided in two similar groups (n=20). All canals were prepared up to size 25 taper .06 using nickel-titanium instrumentation. The canals in the Group SC were obturated using Soft-Core obturators (Kerr, Romulus, Mi, USA), while Group TH canals (n= 20) were obturated using Thermafil Endodontic Obturators (Tulsa Dental Products, Tulsa, OK, USA), strictly following manufacturers' instructions for use. The obturations were analyzed by means of CBCT to measure the distance from the apical limit of obturation to the apical foramen and the presence of voids inside root canals.

RESULTS

There was no significant difference between the two groups in the mean distance of the apical extent of the obturation (t test, p>0.05). Overfilling occurred in only 3 cases (2 in Group TH and 1 in Group SC). The percentages of voids in both groups were very low with no significant difference (Z test, p>0.05).

CONCLUSIONS

The two tested CBO techniques showed similar positive results in terms of performance, even if, after checking with verifiers, in most cases the size of the selected Soft-Core obturator was one size smaller than Thermafil.

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.

Lack of correlation between obturation limits and apical leakage

The aim of this paper was to evaluate a possible correlation between obturation limits and leakage. Thirty-six extracted human mandibular incisors were used, characterized by straight and single canals, non-anatomical complexities, absence of previous endodontic treatment, complete root formation and patent foramen. For standardization of the specimens for the leakage analysis, foraminal instrumentation was performed up to a Flexofile #25 (Dentsply-Maillefer, Ballaigues, Switzerland). All specimens were instrumented and filled following the same protocol, and the obturation limits were measured using Axiovision 4.5 Software (Carl Zeiss Vision, Hallbergmoos, Germany). The specimens were then separated into three groups (n=12) according to the following variables: Group I--obturation limits ranging from 0 mm to 0.76 mm of the main apical foramen. Group II--obturation limits ranging from 0.77 mm to 0.98 mm of the main apical foramen. Group III--obturation limits ranging from 0.99 mm to 1.68 mm of the main apical foramen. Apical leakage was quantified by fluid filtration. The analyses were confronted using Pearson's test (p>0.05). Groups I, II and III showed Pearson correlation values (r2) of -0.152, -0.186 and 0.058, respectively. No correlation was found between the obturation limits and apical leakage.

Effect of canal taper and plugger size on warm gutta-percha obturation of lateral depressions

This study used transparent epoxy-resin root canal models to evaluate different main root canal tapers and various methods of vertical compaction for warm gutta-percha obturation of lateral depressions. The root canal models had straight main root canals with three tapers and four lateral depressions at right angles to the main root canal, 1.0 mm and 3.0 mm from the apex. Three types of experimental stainless steel pluggers with different flat-tip diameters and tapers were used to compact the warm gutta-percha. The Obtura II was used for obturation. After obturation, the depth of penetration into lateral depressions was measured under a stereoscopic microscope, and the effects of root canal taper and plugger size were analyzed by using two-way analysis of variance. The penetration of warm gutta-percha into lateral depressions using the smallest-diameter plugger decreased with increasing main root canal taper. Penetration into lateral depressions increased with the use of pluggers of the correct size. There was a close relationship between plugger size and canal taper. The results suggest that main root canal taper and plugger size should be closely matched so as to promote gutta-percha obturation of lateral depressions.

Synthesis and characterization of a new dimethacrylate monomer based on 5,50-bis(4-hydroxylphenyl)-hexahydro-4,7-methanoindan for root canal sealer application

In this study, a new dimethacrylate monomer 5,5'-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]-hexahydro-4,7-methan-oindan (5,5'-BHMPHM) with molecular weight of 640 and large molecular volume was designed and synthesized. The structure of monomer 5,5'-BHMPHM was confirmed by FT-IR, 1H-NMR and elemental analysis. Degree of double bond conversion, volume shrinkage, contact angle, water sorption and solubility, diffusion coefficient value, flexure strength and modulus of 5,5'-BHMPHM/tri(ethylene glycol) dimethacrylate (TEGDMA) based resin were measured. 2,2-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]-propane(Bis-GMA)/TEGDMA based resin was used as reference. The result illustrated that the double bond conversion, polymerization shrinkage, and diffusion coefficient value of 5,5'-BHMPHM/TEGDMA based resin were significantly lower than that of Bis-GMA/TEGDMA based resin (P<0.05). Water sorption, solubility, flexure strength and modulus of 5,5'-BHMPHM/TEGDMA based resin were higher than that of Bis-GMA/TEGDMA based resin (P<0.05). There was no statistical difference between 5,5'-BHMPHM/TEGDMA based resin and Bis-GMA/TEGDMA based resin in contact angle (P>0.05).

Computer-assisted evaluation of microleakage after apical resection with laser and conventional techniques

The purpose of this in vitro study was to observe the morphological changes and apical dye penetration at apical dentin surfaces after apicoectomy with conventional techniques and laser beam. Sixty single-rooted extracted teeth were selected for the study. The crowns were resected below the cemento-enamel junction. Then, these teeth were treated endodontically and filled with gutta-percha using AH-26 root canal sealer. The teeth were randomly divided into four groups of 15 teeth in each. The roots were resected perpendicular to its long axis 3 mm from the apex using Er: yttrium-aluminium-garnet (YAG) laser irradiation in groups 1 and 2, and the resected root surfaces were lased with Nd:YAG laser in group 2. The apexes were resected by a high-speed handpiece in groups 3 and 4, and the resected root surfaces were lased with Nd:YAG laser in group 4. Ten teeth in each group were used for leakage studies, and the other five teeth were used for scanning electron microscopic examinations. Seven sections were obtained from each root to assess the microleakage, and the sections were analyzed in a computer-assisted manner. No statistically significant differences were observed between the leakage percentage of groups 1 and 3 and groups 2 and 4 (p>0.05). Morphological differences were observed between apical dentin surfaces resected with conventional techniques and laser beam.

A quantitative evaluation of sealing ability of 4 obturation techniques by using a glucose leakage test

OBJECTIVE

The aim of this study was to evaluate the sealing ability of 4 different obturation techniques by using a glucose leakage test.

STUDY DESIGN

Eighty extracted single-rooted maxillary incisors were selected for the study. The teeth were decoronated and the root canals prepared using ProFile rotary instruments to an apical dimension of size 40 (0.06 taper). The specimens were then randomly divided into 4 experimental groups (n = 15) and filled with gutta-percha and sealer by using either cold lateral compaction, warm vertical compaction, Thermafil, or the E & Q Plus system. Another 10 teeth each served as the positive and negative controls. A glucose leakage model was used for quantitative evaluation of the coronal-to-apical microleakage at 24 hours, 1, 2, 3, 5, 8, and 12 weeks.

RESULTS

No significant difference in the cumulative amount of leakage was found among the 4 groups at 24 hours and 1 week (Kruskal-Wallis test, P > .05). Lateral compaction showed significantly more leakage than the other 3 techniques at longer intervals (Mann-Whitney U test, P < .008). No significant difference was found between vertical compaction, Thermafil, and E & Q Plus at all observation times.

CONCLUSIONS

Warm vertical compaction, Thermafil, and the E & Q Plus system showed a better sealing result than cold lateral compaction of gutta-percha at extended observation periods. The glucose leakage method used in this study was able to provide a nondestructive, quantitative, and long-term evaluation of the sealing ability of root canal fillings.

The Radix Entomolaris and Paramolaris: Clinical Approach in Endodontics

Mandibular molars can have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If present, an awareness and understanding of this unusual root and its root canal morphology can contribute to the successful outcome of root canal treatment. This report discusses endodontic treatment of three mandibular molars with a radix entomolaris or paramolaris, both of which are rare macrostructures in the Caucasian population. The prevalence, the external morphological variations and internal anatomy of the radix entomolaris and paramolaris are described. Avoiding procedural errors during endodontic therapy demand an adapted clinical approach to diagnosis and root canal treatment.

SEM analysis of the integrity of resected root apices of cadaver and extracted teeth after ultrasonic root-end preparation at different intensities

AIM

To compare the integrity of root apices of cadaver and extracted teeth after resection, ultrasonic root-end cavity preparation at medium and low ultrasonic power settings and retrieval.

METHODOLOGY

Root canal treatment, perpendicular root-end resection and root-end preparation were performed on single-rooted anterior and premolar teeth (49 teeth in situ in maxillary and mandibular jaws from cadavers and 45 extracted teeth). Apical root-end cavities were prepared with the S12/90 degrees D tip and the Suni-Max ultrasonic unit (Satelec, Merignac, France) at the intensity prescribed by the manufacturer (power 7 at power mode S) (34 cadaver teeth, 30 extracted teeth) and at a lower intensity (power 4 at power mode S) (15 cadaver teeth, 15 extracted teeth). After ultrasonic preparation the cadaver teeth were retrieved from the jaws. Exaflex impressions (GC Corporation, Tokyo, Japan) were made of the root apices after resection, root-end preparation and retrieval. These impressions were processed for SEM analysis, and the recordings evaluated for cracks and marginal chipping.

RESULTS

In general, extracted teeth showed significantly more cracks and chipping than cadaver teeth. Lowering the ultrasonic power from medium to low intensity resulted in equal scores for cracks on extracted teeth and for chipping on cadaver teeth, in higher scores for cracks on cadavers and in lower scores for chipping on extracted teeth. Complete cracks and cracks originating from the root surface occurred only in extracted teeth.

CONCLUSIONS

The number of cracks and degree of chipping caused by ultrasonic root-end preparation was higher on extracted teeth than on cadaver teeth. Lowering the ultrasonic power from medium to low intensity cannot be recommended as it resulted in more cracks and equal chipping on cadaver teeth. Investigation of techniques and materials should be conducted in situ and not on extracted teeth.

Root Canal Treatment in a Mandibular Second Premolar with Three Root Canals

According to the endodontic literature, the possibility of three canals in mandibular second premolars is quite small. When three or more canals are present separation of the root canals has only been described at mid-root level. The present case describes root canal treatment of a root canal aberration at the level of the apical third (apical root canal separation starting at a length of 20 mm) where a combined use of the fiberoptic endoscope and the operating microscope was necessary to locate the canal orifices and to enter these orifices. The present report emphasizes the need of color contrast to enhance visualization.

Longitudinal study on microleakage of three root-end filling materials by the fluid transport method and by capillary flow porometry

AIM

(i) To compare the root-end sealing ability of IRM Caps (IRM), Fuji IX Capsules (Fuji IX) and Pro Root MTA Tooth-Coloured Formula (MTA) in teeth obtained from cadavers. (ii) Further research on leakage study methodology by means of comparison of the fluid transport method (FTM) and capillary flow porometry (CFP).

METHODOLOGY

Root canal treatment was performed on 33 cadaver teeth in situ 2 weeks prior to root resection and ultrasonic retropreparation (S12/90 degrees D-tip on Suni-Max), after which the teeth were retrieved from the cadavers. Two teeth were kept as positive and negative controls. The other teeth were divided in three different groups at random, with each group receiving one of the retrofill materials. Retrofills were exposed to water 5 min after placement. The teeth were stored at 37 degrees C for 12 h after which the root filling was removed. Microleakage (L in microL day(-1)) was measured for 24 h under a pressure of 1.2 atm using FTM and recorded as L = 0, 0 < L < or = 10, L > 10. The measurements were repeated after 1 and 6 months. After 6 months, leakage was also assessed by CFP in order to measure through pores and their diameters. Results were analysed statistically using nonparametric Kruskal-Wallis and Mann-Whitney U-tests, and Spearman correlation coefficients between the results of both methods were calculated. The level of significance was set at 0.05.

RESULTS

(i) A statistically significant difference could be demonstrated between Fuji IX and IRM at 1 month with FTM. FTM revealed a significant difference between Fuji IX and the other materials at 6 months, whereas CFP did not. However, using both methods, Fuji IX showed the best result. (ii) When comparing both techniques, CFP demonstrated through pores in all teeth, whereas with FTM in only 14 of the 31 teeth could through pores be demonstrated. A positive correlation between both methods was demonstrated.

CONCLUSIONS

Under the conditions of this study (i) the conventionally setting glass-ionomer cement Fuji IX showed the best results when used as a root-end material and (ii) CFP appeared to be a useful method for leakage evaluation of through pores in endodontics.

The radix entomolaris in mandibular first molars: an endodontic challenge

AIM

To present cases of mandibular first molars with an additional distolingual root (radix entomolaris, RE) and to survey the literature on the incidence of this anatomical feature.

SUMMARY

A major anatomical variant of the two-rooted mandibular first molar is a tooth with an additional distolingual and third root: the RE. The prevalence of these three-rooted mandibular first molars appears to be less than 3% in African populations, not to exceed 4.2% in Caucasians, to be less than 5% in Eurasian and Asian populations, and to be higher than 5% (even up to 40%) in populations with Mongolian traits. A total of 18 cases (12 root filled and six extracted mandibular first molars) with an RE were collected during the years 2000-2003 in patients of Caucasian origin. As far as the access was concerned, entering the root canal in the RE required a modification of the opening in a distolingual direction resulting in a trapezoidal opening cavity. None of the orifices was located midway between the mesial and distal root component. Based on the anatomy of the extracted samples and the bending of ISO 10 files after scouting of the root canal in the RE, three types of curvature were detected: (I) straight or no curvature (two cases); (II) coronal third curved and straight continuation to the apex (five cases); and (III) curvature in the coronal third and buccal curvature from the middle third or apical third of the root (11 cases).

KEY LEARNING POINTS

Clinicians should be aware of this unusual root morphology in mandibular first molars in Caucasian people. Radiographs exposed at two different horizontal angles are needed to identify this additional root. The access cavity must be modified in a distolingual direction in order to visualize and treat the RE, this results in a trapezoidal access cavity.

Influence of the sealer and a plug in coronal leakage after post space preparation

The subject of this paper was to conduct an in vitro study of the coronal leakage after root canal filling and post space preparation. One hundred single-rooted human teeth had their crowns removed and the canals prepared and filled by the lateral condensation technique with gutta-percha points and the sealers CRCS and Endofill (a Grossman cement). After post space preparation, the remainder of the filling was protected or not with 1mm of a plug of the following materials: Coltosol, Super Bonder (cyanoacrylate-ester), CRCS and Endofill. After 24 hours in saline, the specimens were immersed in a 2% methylene blue solution in a vacuum environment for 24 hours. The teeth were then sectioned longitudinally, leakage was evaluated linearly and the obtained data were submitted to the Kruskal-Wallis test. The results with the two sealers studied were similar between themselves and worse (p<0.01) than the groups with a protector plug. The statistical analysis ordered the experimental groups from the best to the worst in the following way: a - Endofill-Super Bonder, CRCS-Super Bonder, CRCS-CRCS; b - Endofill-Endofill; c - Endofill-Coltosol, CRCS-Coltosol; d - Endofill, CRCS.

Apical Microleakage of Root-End Cavities Prepared by CO2 Laser

This in vitro study in extracted human teeth was designed to compare the degree of dye penetration of root-end cavities prepared by CO2 laser, ultrasonic retrotip, or rotary instrument. Eighty-two human anterior teeth were prepared and obturated with laterally condensed gutta-percha and sealer. Root-end resection was performed at 90 degrees, 3 mm from apex. Root-end cavities were prepared by CO2 laser beam, ultrasonic retrotips, or bur and were filled with amalgam. The teeth were isolated and immersed in basic fuchsin at 36 degrees C for 48 hours. The roots were split longitudinally and examined by a stereomicroscope. Leakage was quantified by linear measurement of dye penetration with the aid of image-analyzing software. Apical leakage in the CO2 laser group was significantly less than in the ultrasonic retrotip and bur groups. The difference between the ultrasonic and bur groups was insignificant. Based on the results of this in vitro study, application of CO2 laser for root-end cavity preparation appears to decrease the apical leakage.

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.