|Year : 2019 | Volume
| Issue : 1 | Page : 51-56
Comparative evaluation of removal of gutta-percha from root canals with laser using different solvents: An in vitro study
Mona Devi1, Pardeep Mahajan1, Shikha Baghi Bhandari1, Prashant Monga1, Nitika Bajaj2, Fatinderjeet Singh1
1 Department of Conservative Dentistry and Endodontics, Genesis Institute of Dental Sciences and Research, Ferozepur, Punjab, India
2 Department of Paedodontics and Preventive Dentistry, Dashmesh Institute of Research and Dental Sciences, Faridkot, Punjab, India
|Date of Web Publication||19-Jun-2019|
Dr. Prashant Monga
Department of Conservative Dentistry and Endodontics, Genesis Institute of Dental Sciences and Research, Ferozepur, Punjab
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study is to evaluate the gutta-percha removal from root canals with diode laser using chloroform and Endosolv E solvents.
Materials and Methods: Thirty freshly extracted permanent human maxillary central incisors with single and straight root canals were selected for the study. Teeth were biomechanically prepared and then obturated. Teeth were then stored in 100% humidity at 37°C for 7 days. Then teeth were randomly divided into three groups based on retreatment method used: Group 1-Only diode laser; Group 2-Diode laser along with chloroform as solvent; Group 3-Diode laser along with Endosolv E (Tetrachloroethylene) as solvent. After completion of retreatment, roots were sectioned longitudinally and viewed under stereomicroscope at 10x magnification. The area of the remaining filling material in each half was measured using Image tool for Windows v. 3.00 software. Data were analyzed by using analysis of variance test followed by post hoc test.
Results: The results showed that all the laser groups left some filling material inside the root canal. However, the specimens retreated with diode laser along with chloroform (Group 2) left less filling material inside the root canals as compared to other groups.
Conclusion: The present study revealed that the diode laser with solvents (Chloroform and Endosolv E) were significantly more effective than only diode laser group in removing gutta-percha during retreatment of the root canal system. Out of these, Group 2 (diode laser along with chloroform as solvent) was more effective than other groups.
Keywords: Chloroform, diode laser, Endosolv E, retreatment, stereomicroscope
|How to cite this article:|
Devi M, Mahajan P, Bhandari SB, Monga P, Bajaj N, Singh F. Comparative evaluation of removal of gutta-percha from root canals with laser using different solvents: An in vitro study. Endodontology 2019;31:51-6
|How to cite this URL:|
Devi M, Mahajan P, Bhandari SB, Monga P, Bajaj N, Singh F. Comparative evaluation of removal of gutta-percha from root canals with laser using different solvents: An in vitro study. Endodontology [serial online] 2019 [cited 2019 Jul 21];31:51-6. Available from: http://www.endodontologyonweb.org/text.asp?2019/31/1/51/260526
| Introduction|| |
Retention of natural teeth in an asymptomatic clinical condition is one of the main goals of endodontic therapy. Endodontic treatment is a dental procedure in which the diseased or damaged pulp of a tooth is removed, and pulp space is filled with an inert material. In this procedure, before doing obturation tooth is biomechanically prepared and adequate irrigation is done to eliminate most of the irritants; as these irritants can cause damage, which may lead to failure of root canal treatment. According to various studies, failure rate is most commonly due to insufficient cleaning, untreated canals, inadequate filling or coronal leakage, postplacement errors, ledge formation, perforations, transportations, fractures and separated instruments.
Nonsurgical retreatment procedures require the complete removal of obturating materials from the endodontic space to facilitate the removal of infection causing micro-organism and disinfection of root canal system. Numerous techniques are available for removing root canal obturating materials such as ultrasonic technique stainless steel hand files (K-files or hedstrom files), gate-glidden drills, heat pluggers, etc.,
Presently many different rotary retreatment systems are available for root canal filling removal. In addition to the use of Ni-Ti rotary instrument, the use of a solvent is also recommended to facilitate the removal of gutta-percha by softening it.
Nowadays, Laser is recommended for gutta-percha removal. Laser has been defined as a device which transmits light of various frequencies and is capable of generating immense heat and power when focused at close range. Studies have shown that laser can melt the gutta-percha material. Removal of root canal filling material by laser involves a combination of both photothermal and photoablation effects.
In this study, laser energy is combined with various solvents to facilitate the removal of root canal obturating material.
Therefore, the aim of the present study is to evaluate the ability of laser in removing root canal obturating materials during retreatment using two different solvents chloroform and Endosolv E (Tetrachloroethylene).
| Materials and Methods|| |
Sample selection-A total of 30 freshly extracted single-rooted noncarious human permanent maxillary central incisors was selected for this study.
- Selection criteria
- Each tooth with-patent canal
- Only root canals in which the first file that fitted at the apex size 15 was included as follows:
- Straight canal
- Completely formed apex
- No abnormal root morphology or noticeable defects.
The selected teeth were cleaned with ultrasonic scaler (P4 Unicorn, Bonart Co. Ltd.,) and stored in purified, filtered water. All the teeth were radiographed preoperatively by using a prefabricated jig, which was designed to provide the same exposure angles and distances for all the specimens. The coronal portions of all the teeth were removed with diamond disk (DFS-Diamon GmbH, Germany), leaving roots 15 ± 1 mm of length and roots were mounted in a standard mold made of putty impression material.
Canal preparation and obturation
A size 15 K-file was introduced into the canal until it was visible at the apical foramen. The working length was determined by substracting 1 mm from this measurement. The cervical third was flared with Gates-Glidden burs (Mani Inc., Japan) till size 3 and 4 in decreasing order. Root canal was prepared using step-back technique with K files (Mani Inc., Japan) with apical size 50. Each canal was irrigated with 2 mL of 3% sodium hypochlorite (PrevestDenPro Ltd., India) solution after every instrumentation. A final rinse of 10 mL of 17% Ethylenediaminetetraacetic acid (Metabiomed Co. Ltd., Korea) was given to remove the smear layer followed by rinsing with a 10 mL of normal saline solution (Beryl drugs Ltd., India). The root canals were dried with paper points (Diadent Group International, Korea) and obturated with Gutta-Percha (Dentsply, Maillefer, Ballaigues, Switzerland) and Tubliseal sealer (Kerr corporation, USA) using cold lateral compaction technique. The coronal access cavities were sealed with a temporary filling material (Orafil G (PrevestDenPro Ltd., India). All teeth were stored at 100% humidity and 37°C for 7 days to allow sealer to set completely. After 7 days, the teeth were removed, air dried and radiographed to check any voids or discrepancy in the obturation.
The teeth were randomly divided into 3 Groups with 10 specimens each, and the temporary filling was removed. Gutta-percha was removed by using one of the following techniques.
- Group 1 (n = 10): Only diode laser
In this group, Gutta-percha was removed by using diode laser (Zolar technology and Mfg) at wavelength 980 nm and of power 5W for 20 s repeatedly until the working length was achieved. After each lasing, gutta-percha remnants and debris were constantly removed with distilled water irrigation during the procedure and remnants on optical fiber tip was wiped with gauge piece. Finally, reamer was used to check the working length
- Group 2 (n = 10): Diode laser with chloroform
In this group, approximately coronal 2 mm gutta-percha was removed by using Gates-glidden burs with size 1 that creates a reservoir for solvent, and 0.1 mL of chloroform (Paskemfinechemical industries, India) was placed into the root canal. Softened gutta-percha was removed by using diode laser at wavelength 980 nm and of power 5 W for 20 s repeatedly until working length was achieved. After each lasing, gutta-percha remnants and debris were constantly removed with distilled water irrigation followed by placement of 0.1 mL of chloroform solvent into the canal and remnants on optical fiber tip was wiped with gauge piece. Finally, reamer was used to check the working length
- Group 3 (n = 10): Diode laser with Endosolv E
In this group, approximately coronal 2 mm gutta-percha was removed by using Gates-glidden burs with size 1 that creates a reservoir for solvent and 0.1 mL of Endosolv E (Septodont Healthcare India Pvt. Ltd., India) was placed into the root canal. Softened gutta-percha was removed by using diode laser at wavelength 980 nm and of power 5 W for 20 s repeatedly until working length was achieved. After each lasing, gutta-percha remnants and debris were constantly removed with distilled water irrigation followed by placement of 0.1 mL of Endosolv E solvent into the canal and remnants on optical fiber tip was wiped with gauge piece. Finally, reamer was used to check the working length.
The laser was performed using a contact mode. Retreatment was considered complete when the tip of laser fiber reached the working length.
The teeth were grooved buccolingually with a diamond disk and sectioned longitudinally with chisel and mallet. Both root halves were photographed with a camera (Sony PC 120, Sony Corporation, Japan) adapted to a stereomicroscope (Nikon, Model SMZ-745T) under ×10 magnification.
To evaluate the remaining filling materials, images taken were transferred to specific software (image tool for Windows v. 3.00, University of Texas Health Science Center, San Antonio, TX, USA) which was used to measure the area of remaining filling material and root canal periphery that was computed and expressed by using square pixels. Mean percentage values were calculated and compared.
For data collection, Microsoft Excel software was used. The results were presented in mean ± standard deviation. The one-way analysis of variance followed by Tukey's post hoc tests was used to compare the study parameters among the groups. The level of significance was set at P < 0.05. All the analysis were carried out on SPSS 16.0 version (Inc., Chicago, IL, USA).
| Results|| |
The results showed that all the laser groups left some filling material inside the root canal. However, the specimens retreated with diode laser along with chloroform (Group 2) left less filling material inside the root canals as compared to other groups [Table 1].
|Table 1: Comparison of mean and standard deviation of groups retreated with diode laser using different solvents for their percentage of remaining filling material using analysis of variance test followed by post hoc test|
Click here to view
| Discussion|| |
According to established principles of root canal treatment, a successful root canal treatment depends on the thorough biomechanical preparation of the root canal followed by three dimensional obturation. For obturation, gutta-percha is used in conjunction with a root canal sealer. Nonsurgical endodontic retreatment is attempted first to remove source of infection from root canal. It has been shown in various studies that the success rate of nonsurgical endodontic retreatment ranges from approximately 65% to more than 80%.,
The main step of root canal retreatment is to remove filling materials from the root canal because this facilitates the effective instrumentation, which in turn allow irrigating solutions to adequately remove irritants such as debris and micro-organism. Although, it has not been proven that any remaining material will cause retreatment failure, removing as much filling material as possible would seem essential because infected remnants in the root canal may lead to persistent disease.
Different methods have been applied to remove filling materials from root canals. These include use of hand files, ultrasonic files, engine-driven Ni-Ti instruments,,, etc., Nowadays, recently laser irradiation technique have been introduced for removal of gutta-percha based filling material in retreatment cases.
The word LASER is an acronym for light amplification by stimulated emission of radiation. Lasers in dentistry are considered to be a new technology which is being used in clinical dentistry to overcome some of the drawbacks posed by the conventional dental procedures. This technology was first used for dental application in the 1960s, but its use has increased rapidly in the last few decades.,
Lasers are classified according to their location on the electromagnetic spectrum of light. They can be visible and invisible, near, medium, and far infrared laser. Owing to optical physics, the function of the various lasers in clinical use differs. The lasers considered for endodontic applications are the near infrared laser – diode (810, 940, 980, and 1064 nm) and Nd: YAG (1,064 nm). Recently, laser technology was introduced to endodontics with the goal of improving the results obtained with traditional procedures though the use of light energy to remove debris and the smear layer from the root canals and also disinfecting the endodontic system.
Laser devices with different wavelengths that could be absorbed in different tissues and materials seem promising for removing root canal filling material. The heating effect of laser beam is largely responsible for achieving this goal (Viducić et al.).
Basic mechanism of photothermal effect states that the photon energy of the laser is converted into thermal energy. The thermal energy then produces heat, which subsequently melts filling material in the root canal., The energy is emitted in a continuous wave (CW mode). Mechanical interruption of the energy emission is possible which allow for better control of thermal emission.
Almost all wavelengths emitted by laser can destroy the microbial cell wall due to their photothermal effect. Because of the structural characteristics of the different cell walls, Gram-negative bacteria are more easily destroyed with less energy and radiation than Gram-positive bacteria. The thermal effect of the radiation penetrates up to 1 mm into the dentinal walls, allowing for a decontaminating effect on deeper dentine layers.
Thus, diode laser of near infrared spectrum operating at wavelength of 980 nm having power of 5W that delivers the beam through flexible optical fiber having diameter 300 μm was used in this study to evaluate its efficacy in the removal of root canal filling material from root canals.
Wilcox reported that to remove the obturated materials from root canals, many kinds of solvents including eucalyptol, halothane, Endosolv E, xylene, chloroform, and xylol were used to soften or dissolve gutta-percha. Gu et al. reported that chloroform is more effective in dissolving gutta-percha as compared with eucalyptol, halothane, and xylol.
Sae-lim et al. reported that Endosolv E containing tetrachloro-ethylene is used in the procedure to soften the root canal filling material. This also avoids the formation of a film of gutta-percha on the canal walls.
The heating of chemical solvents may be advantageous, as they are more effective at higher temperature. Warming the solvent increases its chemical reactivity, which increases the rate at which it softens and dissolves gutta-percha.,
In the present study, we used chloroform and Endosolv E as a solvent to soften the gutta-percha filling material from root canals as an adjunct to diode laser.
It was observed that mean amount of residual filling material remaining inside the canal after retreatment procedure was significantly less in group retreated with combination of diode laser with chloroform. Group 1 (Diode laser) showed highest amount of remaining root canal filling material as compared to other groups. There was statistical significant difference between Group 1 (only diode laser) and Group 2 (diode laser with chloroform). There was also statistical significant difference between Group 1 (only diode laser) and Group 3 (diode laser with Endosolv E). However, there was no statistically significant difference between Group 2 (diode laser with chloroform) and Group 3 (diode laser with Endosolv E).
This result is in accordance with previous studies, in which Anjo et al. examined the usefulness of soft-tissue laser (Nd: YAG) in the removal of filling materials in extracted teeth.
Wilcox advocated using the hot instrument with chloroform to remove the root canal filling material. The success rate of removing filling material from the root canal using chloroform was approximately 85%.
Bodrumlu et al. compared the efficacy of removal of root canal filling material with the conventional method (Gates-glidden drills) with chloroform. They demonstrated that conventional method (Gates-glidden drills) with chloroform worked best in removing the root canal filling material.
Wourms et al. evaluated the efficacy of solvent Endosolv E in dissolving gutta-percha with rise in temperature. They demonstrated that with increase in temperature there was a significant improvement in the dissolution of gutta-percha with solvent Endosolv E.
As mentioned in previous study, Tamse et al. presented a method in which four gutta-percha solvents (Chloroform, xylene, Endosolv E, and orange oil) were compared. After comparison it was observed that chloroform was most effective solvent among all types of solvents; however, there was no significant difference between chloroform and Endosolv E.
Duarte et al. employed different methods to evaluate retreatment techniques such as radiography, clearing, projection of photograph onto a screen, stereomicroscope, scanning electron microscopy, evaluation of digitized images using a scanner, microcomputed tomography, and computed tomography. In earlier retreatment studies, remaining gutta-percha was assessed radiographically, or residual gutta-percha was measured using evaluation scales for example, severe, moderate, mild, or no debris. Each of these techniques has its own limitations.
In the present study, the amount of remaining filling material was evaluated by longitudinal cleavage and quantitative analysis. The teeth were grooved buccolingually with a diamond disk and sectioned longitudinally with chisel and mallet as done in study conducted by Giuliani et al. 2008.
The present study used a specific computer software image tool for Windows v. 3.00 for analysis of area of remaining filling material in square pixels. This is in agreement with Fariniuk et al., 2011 who reported that delineation of the remaining filling material with aid of software's is more precise than the utilization of scores; this precision is related to image magnification on the computer, providing better quality of images.
There are few limitations of the present study as only straight single-rooted maxillary central incisors were used in present study. There may be different cleaning efficacy of retreatment systems in severely curved and anatomically complex root canals. In this study, specimens were sectioned longitudinally. The problem of sectioning is that the filling debris can be displaced and the technique ends up being unpredictable. Images viewed from just one direction do not indicate the thickness of debris.
| Conclusion|| |
Diode laser with chloroform and diode laser with Endosolv E were significantly more effective than only diode laser in the removal of gutta-percha from the root canal.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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