|Year : 2016 | Volume
| Issue : 2 | Page : 143-147
Comparative evaluation of dissolution of a new resin-coated Gutta-percha, by three naturally available solvents
Gaurav Kulkarni, Rajesh Podar, Shishir Singh, Shifali Dadu, Rucheet Purba, Shashank Babel
Department of Conservative Dentistry and Endodontics, Terna Dental College and Hospital, Nerul, Navi Mumbai, Mumbai, Maharashtra, India
|Date of Web Publication||9-Dec-2016|
Department of Conservative Dentistry and Endodontics, Terna Dental College and Hospital, Sector 22, Nerul, Navi Mumbai - 400 706, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Introduction: The aim of this study was to evaluate and compare the effectiveness of eucalyptus oil, orange oil, and clove oil in dissolving resin-coated Gutta-percha (RCGP) cones.
Materials and Methods: RCGP cones (EndoREZ,) (n = 70) and conventional GP cones (n = 70) with ISO size 25 and 4% taper were used for the study. Cones of each type were divided into three groups of twenty each, for immersion in eucalyptus oil, clove oil, and orange oil for 5 and 15 min immersion times. Ten GP cones from each group served as control and were immersed in distilled water. Each sample was weighed initially before immersing in the respective solvents. Cones were removed after specified immersion period, washed in distilled water, and allowed to dry. The samples were then re-weighed and statistical analysis was done.
Results: Orange oil was most effective in dissolving both RCGP and conventional GP when compared to eucalyptus and clove oil. RCGP dissolved more readily than conventional GP in orange oil.
Conclusion: Orange oil was the most effective solvent of EndoREZ RCGP and conventional GP among all tested solvents.
Keywords: EndoREZ; Gutta-percha; resin-coated Gutta-percha; root canal solvents.
|How to cite this article:|
Kulkarni G, Podar R, Singh S, Dadu S, Purba R, Babel S. Comparative evaluation of dissolution of a new resin-coated Gutta-percha, by three naturally available solvents. Endodontology 2016;28:143-7
|How to cite this URL:|
Kulkarni G, Podar R, Singh S, Dadu S, Purba R, Babel S. Comparative evaluation of dissolution of a new resin-coated Gutta-percha, by three naturally available solvents. Endodontology [serial online] 2016 [cited 2019 May 25];28:143-7. Available from: http://www.endodontologyonweb.org/text.asp?2016/28/2/143/195442
| Introduction|| |
Retreatment procedures in endodontic practice require complete removal of the original root filling mass. Despite a number of advancements in obturating materials, Gutta-percha (GP) still remains the most common and popular core obturating material., The techniques used for the removal of GP can be mechanical, thermal, chemical, or a combination of these. Chemical method involves the use of various solvents to soften GP and facilitate its removal with hand or rotary instruments from the root canal system. In addition, Cavenago et al. have even shown that irrigation by GP solvents in an attempt to clean the root canals with paper points enhanced the removal of materials during endodontic retreatment of anatomically complex teeth.
Several solvents have been tested for their ability to dissolve GP so far [Table 1]. Although chloroform and xylene are popular GP solvents, historically they are toxic and potential carcinogens.,, Artificial solvents such as tetrachloroethylene have also been used for this purpose. However, the easy availability and economic feasibility of naturally available solvents such as eucalyptus oil, clove oil, and orange oil is often preferable.
EndoREZ resin-coated GP (RCGP) cones (Ultradent Products, Inc., South Jordan, UT) are used with EndoREZ sealer in an attempt to secure a bond between sealer and GP establishing a tertiary monoblock. However, there is limited data regarding dissolution of EndoREZ RCGP cones with the commonly used naturally available solvents. The aim of the present study was to evaluate dissolving ability of three naturally available solvents viz., eucalyptus oil, orange oil, and clove oil on EndoREZ RCGP as compared to conventional GP. The null hypothesis tested was that the solvents tested had no dissolving effect on EndoREZ RCGP and conventional GP.
| Materials and Methods|| |
Seventy EndoREZ cones (Ultradent Products, Inc., South Jordan, UT) and seventy conventional GP cones (Dentsply Maillefer, Baillaigues, Switzerland) with ISO size 25 and 4% taper were selected for the study. [Figure 1] shows the materials and methodology employed in this investigation. GP cones of each group were divided into three groups of twenty each for immersion in eucalyptus oil (SVAS enterprises, Mumbai, India), clove oil (Ashwin Chemical Co., Mumbai, India), and orange oil (Dr. Jains Forest Herbals Pvt. Ltd., Mumbai, India). They were further divided into two equal subgroups (n = 10) to test their dissolution for an immersion time of 5 and 15 min, respectively. The remaining ten GP points in each group served as control and were immersed in distilled water.
|Figure 1: Three solvents viz., eucalyptus oil (a), clove oil (b), and orange oil (c) were tested for their ability to dissolve EndoREZ resin-coated Gutta-percha points (d) and conventional Gutta-percha points (e), Gutta-percha points were placed in glass vials containing 5 ml of test solvents for 5 and 15 min intervals (f and g). Points were then washed, dried at 37°C for 24 h, (h) and weighed on a Sartorius balance (i)|
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About 5 ml of respective solvents were kept ready in a glass vial at room temperature. Each cone was weighed on a GP 600 P Sartorius balance (accuracy, 0.0001 g) and noted as preimmersion weight, before immersing it in the solvent. The lid of the vial was replaced and timing was noted with a stop watch. The samples were then removed from the glass vial after specified immersion period of 5 or 15 min and washed in 100 ml of distilled water. GP cones were then allowed to dry for 24 h at 37°C in a humidifier following which they were reweighed. This was noted as postimmersion weight. The extent of GP dissolved from the specimen was calculated by the difference between the original weight of GP, and its final weight using the final equation.,
M = M2− M1.
Where M2= Postimmersion weight, M1= Preimmersion weight.
Percentage loss of weight was calculated at each time interval for each solvent, material, and sample. Data for percentage of weight loss in different solvents for immersion periods of 5 and 5 min is expressed as means and standard deviations. The mean percentage of weight loss values were compared for differences using a two-way ANOVA; first factor being the material (conventional GP and EndoREZ), and second factor being the solvent (eucalyptus oil, orange oil, clove oil, and control). The mean percentage of weight loss values was compared for differences between GP and EndoREZ using unpaired t-test for individual subgroups (based on time of exposure and solvents used). One-way ANOVA was used for analyzing the differences in the percentage of weight loss with different solvents for individual materials at individual times (5 and 15 min). This was followed by post hoc multiple comparisons (pair-wise) using Scheffe's test. All statistical testing was done using significance set at 0.05. The data were analyzed in the statistical analysis software MedCalc version 12.7.5 (MedCalc Software bvba, Ostend, Belgium).
| Results|| |
The mean percentage weight loss values for EndoREZ RCGP and conventional GP for the tested solvents at 5 min and 15 min are presented in [Table 2] and [Table 3], respectively. For both 5 and 15 min immersion times, orange oil showed a significantly higher (P< 0.0001) capacity to dissolve both EndoREZ RCGP and conventional GP than eucalyptol and clove oil. However, when dissolving the capacity of EndoREZ and conventional GP in orange oil was compared, EndoREZ was found to dissolve more readily for both immersion times. There was no difference in percentage weight loss values of both the test materials in clove oil and eucalyptus oil for both immersion periods (P > 0.05). For the control group of distilled water, EndoREZ and conventional GP did not show any weight loss indicating no dissolution. At 5 min immersion period, conventional GP showed marginally higher dissolution than EndoREZ in clove oil (P< 0.05).
|Table 2: Mean (standard deviation) percentage of weight loss of EndoREZ resin-coated Gutta-percha and conventional Gutta-percha in different solvents at 5 min|
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|Table 3: Mean (standard deviation) percentage of weight loss of EndoREZ resin-coated Gutta-percha and conventional Gutta-percha in different solvents at 15 min|
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| Discussion|| |
Nonsurgical retreatment of previously filled root canal requires complete removal of GP and sealer from the root canal walls. Apical access in endodontic retreatment is gained through the removal of filling materials from the root canal. Orange oil, eucalyptol, and clove oil have been investigated since early 1990's for their dissolving ability of GP., Endodontic literature regarding the dissolution of conventional GP has been inconsistent with some reports suggesting orange oil to be a superior solvent than eucalyptol,,, whereas others showing no difference between them.,, Whether the resin coating inhibits the contact between the solvent and GP, thereby slowing the dissolution time is not clearly known. Hence, the retrievability of newer endodontic core materials such as EndoREZ RCGP with the help of naturally available economic solvents needs to be investigated adequately.
Various methods have been employed to determine the softening or dissolution of GP by solvents. While some investigators fabricated GP discs from molds,,,, and determined solubility, others determined softening by noting the depth of penetration of plugger into softened GP., The current study determined the ability of RCGP to get dissolved as complete mechanical removal of GP is not possible from the intricacies root canal system, and dissolution by solvents may facilitate its removal more efficiently. The methods used in the present study were similar to the one employed by Mustaq et al., due to its simplicity and ease of reproducibility.
Eucalyptus oil and clove oil had similar effects on EndoREZ and conventional GP (P > 0.05), but none was as effective as orange oil. These findings differ from those of Faria-Junior et al., who observed similar dissolving efficacy of orange oil and eucalyptol on EndoREZ. This difference in results can probably be attributed to the methodology employed. While immersion of the points in the current study was done without any modification, Faria-Junior et al., fabricated rings of EndoREZ and GP by heating the materials up to 70°C followed by pressing them in molds. This would have caused structural change of the RCGP and conventional GP points, thus affecting its physical properties and solvent effect.
It was very interesting to note that orange oil dissolved EndoREZ more aggressively than conventional GP. The mean percentage of weight loss for EndoREZ and conventional GP in orange oil was 22.94 ± 8.24 versus 8.41 ± 3.66, respectively, for an immersion time of 5 min, and 48.89 ± 13.49 versus 13.49 ± 5.80, respectively, for 15 min. This difference in dissolution could probably be a function of variation in composition. Some manufacturers include low quantities of waxes in their formula. Changes in the content of resin or wax may result in solubility differences. Since manufacturers avoid publishing their formula, it is difficult to come to any conclusions on this matter.
While the cytotoxicity of orange oil was uncertain earlier, Scelza et al. have confirmed that it is less cytotoxic when compared to eucalyptol and recommended its use safely in the root canal. One should be aware that although the methodology used in the present study gives an insight of dissolving capacity of the solvents tested for EndoREZ at a contact time of 5 or 15 min; yet the results can only be partly transferred to a clinical situation. In contrast to the study conditions, only a part of the core obturating material will be in direct contact with the solvent limiting dissolution of RCGP. Several other clinically relevant parameters such as temperature, solvent dilution by irrigants and biological fluids, and volatility of solvents were not a part of the present study and comprise the limitations of this investigation. In addition, it is worth noting that all the cited studies including the present one have a tendency to overestimate the dissolving efficacy of the tested solvents, as aged GP in a failing root canal will always be harder and more brittle than a recently manufactured one. However, for the sake of standardization, all tested GP samples in this study were carefully selected such that they had the same manufacturing and inspection dates and came from the same lot.
| Conclusion|| |
The null hypothesis partially accepted as it was noted that all solvents except clove oil dissolved EndoREZ RCGP. Within the limitations of this investigation, the following conclusions were made; first, orange oil was the most effective solvent of EndoREZ RCGP and conventional GP amongst all tested solvents, and second, EndoREZ RCGP dissolved more readily in orange oil than conventional GP.
Our observations support the use of orange oil as a solvent during retrieval of EndoREZ RCGP cones from the root canal system.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]