Hasanen H. Al-Khafagy1 , Mohammed Mustahsen ur Rehman2 , Yusuf Noorani3
1. Assistant Professor, Faculty of Dentistry, Restorative Department, Ajman University of Science & Technology, UAE.
2. Associate Professor, Faculty of Dentistry, Periodontology Department, Ajman University of Science & Technology, UAE.
3. General Dentist, Faculty of Dentistry, Oral Diagnosis Department, Ajman University of Science & Technology, UAE.
Corresponding author: “Dr. Hasanen H. Al- Khafagy” dentalhasanen@yahoo.com
J Pak Dent Assoc 2009; 18(1):005-008
Objective:
The aim of this study was to compare the sealing ability of three obturation techniques, cold lateral condensation, carrier based thermafill, and resilon with epiphany sealer using lateral condensation technique.
Methodology:
Forty five single rooted extracted human teeth were selected and randomly divided into three groups, containing 15 in each group, setting aside six teeth as positive and negative control groups. They were obturated with gutta percha and adseal sealer using cold lateral condensation and carrier based thermafill with adseal sealer and with resilon and epiphany sealer using lateral condensation technique. The apical leakage was measured using dye penetration methodology.
Results:
The teeth filled with gutta percha and adseal using cold lateral compaction technique showed the least apical leakage, while the most apical leakage was shown with resilon.
Conclusion:
Based on the data of this study, all groups produced a satisfactory seal. However, resilon and epiphany sealer showed the most apical leakage.
Keywords:
Apical leakage, dye penetration, resilon, root canal filling, root canal obturation technique, thermafill.
Introduction
Gutta-percha has been the standard obturation material used in root canal therapy since its introduction in 1914 by Callahan. The three main functions of obturation are to entomb any bacteria remaining within the root canal system; to stop the influx of periapical tissue-derived fluid from reentering the root canal to feed the surviving bacteria; and to prevent coronal leakage of bacteria.’
Although gutta-percha has many desirable properties, including chemical stability, biocompatibility, non-porosity, radiopacity and the ability to be manipulated and removed, it does not always meet the three main functions
Gutta-percha does not bond to the internal tooth structure, resulting in the absence of a complete seal. This produces a poor barrier to bacterial micro leakage and is considered to be one of the weakest points in root canal therapy.2
Many attempts have been made to resolve the problem through variations in obturation technique including vertical and lateral condensation and the use of reverse-fill (Obtura II, Obtura Spartan, Fenton, Mo.) or touch and heat (System B, SybronEndo, Orange, Calif.). These methods have reduced micro leakage to a certain degree but have still failed to eliminate the problem.3
Within the last couple of years, new strides have been made to overcome the problem of micro leakage. The disadvantages of gutta-percha in endodontic therapy have led to a call for new and improved products, and one such product is the resilon / epiphany (R/E) system (Pentron Clinical Technologies, Wallingford, Conn.). Resilon is a synthetic, thermoplastic resin filling material that is believed to overcome the limitations and problems with gutta-percha. The system consists of epiphany primer, epiphany sealer and resilon core material. Obturation using this system creates a bonded seal with the dentinal tubules within the root canal system. In essence, it produces a “monoblock” effect, where the core material, sealer and dentinal tubules become a single solid structure, thus meeting Figdor’s criteria.’
The purpose of this study was to compare the apical sealing ability of three different oburation techniques, cold lateral condensation, carrier based thermafill, and resilon with epiphany sealer using lateral condensation technique by means of dye penetration test
Methodology
Fifty one single rooted teeth were randomly selected, stored in 5.25% NaOC1 for twenty four hours and then steam sterilized at 121° C/ 20 psi. Radiographs were then taken in the mesiodistal and bucculingual directions to confirm singularity of the canals. Teeth were sectioned with trimer up to the CEJ, working length determined by visual observation of size 15 k-type (Kerr, Romulus, MI, USA) file passing beyond the apical foramen for each tooth.
Instrumentation of the canals done using standardized technique and final coronal flare with gates-glidden drills (Dentsply, Maillefer, Switzerland) in low speed hand piece.
All teeth were irrigated with 5 ml of 3% Na0C1 solution between each files, after completion of the instrumentation all canals were irrigated using 17 % EDTA solution (10m1) (Canal +, Septodent, France) for 60 seconds to remove the smear layer. Final irrigation was done using 10 ml normal saline and the canals were dried using absorbent paper points (tgdent, England). The roots were then divided randomly into three equal groups, containing fifteen in each group setting aside six roots as positive and negative control group.
Group 1: Obturated with adseal (Meta Biomed, Korea) and gutta percha (tgdent, England) using cold lateral compaction technique.
Group 2: Obturated with epiphany sealer and resilon / epiphany (Epiphany, Pentron Clinical Technologies, CT, USA) using cold lateral compaction technique.
Group 3: Obturated with adseal and gutta percha using carrier based thermafill (Dentsply, Maillefer, Switzerland) technique.
Group 4: Negative control group (three samples).
Group 5: Positive control group (three samples)
All samples were then stored in saline solution at 37° C for 48 hours. The roots were then washed, dried and all surfaces of the roots were painted with nail varnish except for the apical 2mm.
The negative control group consisting of three roots filled with gutta percha and sealer and then painted completely with nail varnish.
The positive control group consisting of three roots filled with gutta percha and sealer and then all surfaces were painted with nail varnish except the coronal access and the apical 2 mm.
Specimens were then placed in 2% methylene blue dye solution for 6 days at 37° C. After removing the specimens from the dye solution they were washed and dried.
Roots were then sectioned longitudinally in the buccolingual direction through the center of the root.
Pictures were then taken of each section with the measuring ruler (HSL 247-00) placed beside the section.
Linear apical leakage was then measured from the apical to the coronal extent of the methylene blue dye penetration after these pictures were magnified up to three times Figure 1.
The obtained results were analyzed statistically using
the Bonferroni adjusted Mann-Whitney-U test.
Results
The negative control specimens showed no dye penetration where as the positive control specimens showed dye leakage of up to 3 mm both coronally and apically. The mean of the depth of dye penetration of all the three groups is shown in Table I below
The analysis of variance showed a statistically significant difference among the apical leakage of the three groups (p < 0.05). Gutta- percha with adseal sealer exhibited the least mean apical leakage value (6.46 mm; SD: 4.27), resilon with epiphany sealer exhibited the most mean apical leakage value (13.47 mm; SD: 3.04), while thermafill with adseal sealer showed significantly more mean apical leakage value than gutta percha (8.43 mm; SD: 4.49), but it showed significantly less apical leakage than the teeth filled with resilon and epiphany sealer
Discussion
Three dimensional sealing of the root canal is one of the main goals of endodontic treatment and is essential for preventing apical and coronal leakage in the root canal system. Several test methods have been described to evaluate the sealing quality of obturated root canals. The most popular method is the dye penetration test. Dye penetration studies are commonly used because they are easy to accomplish and don’t require sophisticated materials.4
Methylene blue dye was used in this study because it easily allows quantitative measurement of the extent of the dye penetration by linear measurement techniques. Its molecular size is similar to bacterial by products such as butyric acid which can leak out of infected root canals to irritate periapical tissues.5
Cleaning the dentinal surface by removing the smear layer is an essential step in the process of successful root canal treatment.6 In this study the smear layer was removed by the alternating use of NaOC1 and EDTA in order to improve the adaptation of the sealer to the canal wall.
New materials and techniques have been introduced to increase the potential for successful outcomes to create a better interface between the walls and the root canal filling material to decrease the leakage.
This study showed that, none of the root canal filling materials and sealers exhibited a complete sealing. However, teeth filled with gutta percha by cold lateral condensation technique exhibited the least apical leakage
and was found to be the best root canal filling material when compared to the teeth filled with other techniques. Teeth filled with gutta percha using thermafill technique showed a considerable amount of apical leakage, however, the worst apical sealing was seen in the teeth filled with resilon and epiphany sealer.
When compared to previous studies, this study showed a significant difference in the results, previous studies state that the teeth filled with resilon and epiphany sealer show significantly less apical leakage than those filled with gutta percha.” This study on the other hand, proves that teeth filled with gutta percha show significantly less apical leakage when compared to the teeth filled with resilon and epiphany sealer.
One explanation being for the possible failure of resilon / epiphany system is the shrinkage stresses that occur during curing of the resin material which can actually dislocate the newly bonded surfaces leading to incomplete sealing of the root canal system, which is described by Fielzer and othersn‘ll as the ratio (configuration factor, or C-factor) of surface area of the fixed walls bounding the tooth preparation versus unbounded walls. As the value of the C-factor is great in this case, increased polymerization shrinkage results in an incomplete sealing of the root canal system, leading to a greater leakage into the root canal system.
Conclusions
Although new materials and techniques have been introduced to create a better sealing of the root canals systems, gutta percha has proven itself over time as a successful root canal filling material and still remains the best root canal filling material showing the least apical leakage.
However, the new obturation materials and techniques still require a lot of time to be investigated further to be able to replace gutta percha as a prime root canal filling material.
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