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Evaluation of gutta-percha solvents
0099-2399/90/1611-0539/$02.00/0 JOURNAL OF ENDODONTICS Copyright 9 1990 by The American Association of Endodontists
Printed in U.S.A.
VOL. 16, NO. 11, NOVEMBER1990
Evaluation of Gutta-percha Solvents Gary J. Kaplowitz, DDS, MA, MEd
Five solvents (rectified white turpentine, oil of melaleuca, eucalyptol, white pine oil, and pine needle oil) were compared with chloroform for their ability to dissolve gutta-percha. All solvents dissolved at least 50% of the gutta-percha in 15 min at 37~ with chloroform and rectified white turpentine dissolving the gutta-percha completely.
weighing 15 mg, which had been stored at room temperature, was dropped into the center of the solvent. The cap was replaced and the bottle returned to the water bath for 15 min. At the end of the cycle, each jar was manually agitated for 20 s. The contents of the bottle then were poured onto a neutral white ceramic tile for visual inspection. The bottle and cap were also examined for remnants of partially dissolved guttapercha. Extent of dissolution was determined by measuring the length of each fragment of undissolved gutta-percha with a caliper and comparing it to a model which related length to weight (4). The model utilized a right circular cone whose dimensions simulated the dimensions of the intact #25 guttapercha segment prior to immersion in the solvent. The length of an undissolved fragment of gutta-percha could be related to a frustum (5) of the right circular cone model (formed by transection of the intact cone). Thus, it was possible to calculate the weight of an undissolved gutta-percha fragment by measuring its length and referring to the model. There were two possible outcomes: the gutta-percha was either partially or completely dissolved. Partial dissolution was defined as greater than 50% but less than 95% of the gutta-percha going into the solution. Complete dissolution was defined as greater than 95% of the gutta-percha going into the solution. Data were recorded as either partial or complete dissolution for each sample. Data were analyzed with Fisher's exact test.
Gutta-percha is a frequently used solid root canal filling material. Several methods of softening or partially dissolving gutta-percha are used in root canal obturation and guttapercha removal procedures. Although chloroform and xylene are excellent solvents of gutta-percha, they are toxic (1) and may be carcinogenic (2). Furthermore, the U.S. Food and Drug Administration banned the use of chloroform for human subjects in 1976 (3). Recent studies have failed to yield a suitable alternative solvent to chloroform or xylene for dissolving or softening gutta-percha. The purpose of this study was to compare the dissolution of gutta-percha in chloroform to that in other solvents with lower toxicity and less potential for carcinogenesis. M A T E R I A L S AND M E T H O D S Solvents capable of partially or completely dissolving guttapercha at room temperature were identified in a pilot study. These solvents were selected for the experimental groups in this study and included rectified white turpentine (Lorann Oils, Lansing, MI), oil of melaleuca (Lorann Oils), eucalyptol (Sultan Chemists, Englewood, N J), white pine oil (Lorann Oils), and pine needle oil (Lorann Oils). Chloroform (Sultan Chemists) served as the positive control. Each group consisted of 10 samples. The experimental procedure was the same for each sample. Fifteen milliliters of solvent were placed into a 30-ml amber glass bottle with a screw cap. Amber glass receptacles were selected because many essential oils are inactivated by visible light. Each bottle was placed in a water bath at 37~ so that the level of the water bath was 5 m m above the level of solvent. The solvent temperature was allowed to rise to 37~ over a period of 20 min. The temperature of the solvent was measured directly with a mercury bulb thermometer (#S80005-B; Sargent-Welch, Skokie, IL). Then the bottle was removed from the bath, the cap unscrewed, and a standardized conical segment of a #25 gutta-percha cone (Mynol)
RESULTS Chloroform and rectified white turpentine completely dissolved the gutta-percha. Oil of melaleuca, pine needle oil, eucalyptol, and white pine oil partially dissolved the guttapercha. Results were statistically significant (p < 0.0001).
DISCUSSION The results indicate that rectified white turpentine may be a suitable alternative to chloroform and xylene for dissolving or softening gutta-percha. It is not carcinogenic and is biocompatible (6, 7). It is used as an expectorant, carminative, diuretic, and anthelmintic in a number of common pharmaceuticals (8, 9). Oil of melaleuca, pine needle oil, and white pine oil also may prove to be useful in softening gutta-percha. Moreover, they all have excellent biocompatibility (10). Rectified white turpentine, pine needle oil, and white pine oil are inexpensive and readily available in the United States as are 539
540
Kaplowitz
Journal of Endodontics
pine needle oil and oil of white pine. Eugenol, eucalyptol, and melaleuca are obtained from foreign sources and are more expensive. Dr. Kaplowitz is senior dental officer, U.S. Coast Guard Support Center Seattle, Seattle, WA and a former resident, Advanced Education Program in General Dentistry, Wilford Hall USAF Medical Center, Lackland Air Force Base, TX.
References 1. Brodin P, Roed A, Aars H, Orstavik D. Neurotoxic effects of root filling materials on rat phrenic nerve in vitro. J Dent Res 1982;61:1020-3. 2. U.S. Food and Drug Administration. Memorandum to state drug officials.
Washington, DC: U.S. Government Printing Office, 1974. 3. U.S. Food and Drug Administration. Chlorofrom, use as an ingredient (active or inactive) in drug products. Federal Register No. 26845. Washington, DC: U.S. Government Printing Office, 1974. 4. Fogiel M. The geometry problem solver: plane, solid, analytic. Piscataway, NJ: Research and Education Association, 1988:861-4. 5. Downing, D. Calculus: the easy way. 2nd ed. New York: Barron's Educational Series, 1982:189. 6. Damas J, Deflandre E. The mechanism of the anti-inflammatory effect of turpentine in the rat. Arch Pharmaco11985;327:143-52. 7. Damas J, Remacle-Volon G, Deflandre E Further studies of the mechanism of counter irritation by turpentine. Arch Pharmaco11986;332:196-202. 8. Tyler V. Pharmacognosy. 9th ed. Philadelphia: Lea & Febiger, 1988:110. 9. Hoover J (ed.). Remington's pharmaceutical sciences. 15th ed. Philadelphia: Mack Publishing Co., 1975:804. 10. The United States Pharmaceutical Convention. United States Pharmacopeia. 21st ed. Baltimore: The United States Pharmaceutical Convention, Inc. 1985:1562, 1587.
Printed in U.S.A.
VOL. 16, NO. 11, NOVEMBER1990
Evaluation of Gutta-percha Solvents Gary J. Kaplowitz, DDS, MA, MEd
Five solvents (rectified white turpentine, oil of melaleuca, eucalyptol, white pine oil, and pine needle oil) were compared with chloroform for their ability to dissolve gutta-percha. All solvents dissolved at least 50% of the gutta-percha in 15 min at 37~ with chloroform and rectified white turpentine dissolving the gutta-percha completely.
weighing 15 mg, which had been stored at room temperature, was dropped into the center of the solvent. The cap was replaced and the bottle returned to the water bath for 15 min. At the end of the cycle, each jar was manually agitated for 20 s. The contents of the bottle then were poured onto a neutral white ceramic tile for visual inspection. The bottle and cap were also examined for remnants of partially dissolved guttapercha. Extent of dissolution was determined by measuring the length of each fragment of undissolved gutta-percha with a caliper and comparing it to a model which related length to weight (4). The model utilized a right circular cone whose dimensions simulated the dimensions of the intact #25 guttapercha segment prior to immersion in the solvent. The length of an undissolved fragment of gutta-percha could be related to a frustum (5) of the right circular cone model (formed by transection of the intact cone). Thus, it was possible to calculate the weight of an undissolved gutta-percha fragment by measuring its length and referring to the model. There were two possible outcomes: the gutta-percha was either partially or completely dissolved. Partial dissolution was defined as greater than 50% but less than 95% of the gutta-percha going into the solution. Complete dissolution was defined as greater than 95% of the gutta-percha going into the solution. Data were recorded as either partial or complete dissolution for each sample. Data were analyzed with Fisher's exact test.
Gutta-percha is a frequently used solid root canal filling material. Several methods of softening or partially dissolving gutta-percha are used in root canal obturation and guttapercha removal procedures. Although chloroform and xylene are excellent solvents of gutta-percha, they are toxic (1) and may be carcinogenic (2). Furthermore, the U.S. Food and Drug Administration banned the use of chloroform for human subjects in 1976 (3). Recent studies have failed to yield a suitable alternative solvent to chloroform or xylene for dissolving or softening gutta-percha. The purpose of this study was to compare the dissolution of gutta-percha in chloroform to that in other solvents with lower toxicity and less potential for carcinogenesis. M A T E R I A L S AND M E T H O D S Solvents capable of partially or completely dissolving guttapercha at room temperature were identified in a pilot study. These solvents were selected for the experimental groups in this study and included rectified white turpentine (Lorann Oils, Lansing, MI), oil of melaleuca (Lorann Oils), eucalyptol (Sultan Chemists, Englewood, N J), white pine oil (Lorann Oils), and pine needle oil (Lorann Oils). Chloroform (Sultan Chemists) served as the positive control. Each group consisted of 10 samples. The experimental procedure was the same for each sample. Fifteen milliliters of solvent were placed into a 30-ml amber glass bottle with a screw cap. Amber glass receptacles were selected because many essential oils are inactivated by visible light. Each bottle was placed in a water bath at 37~ so that the level of the water bath was 5 m m above the level of solvent. The solvent temperature was allowed to rise to 37~ over a period of 20 min. The temperature of the solvent was measured directly with a mercury bulb thermometer (#S80005-B; Sargent-Welch, Skokie, IL). Then the bottle was removed from the bath, the cap unscrewed, and a standardized conical segment of a #25 gutta-percha cone (Mynol)
RESULTS Chloroform and rectified white turpentine completely dissolved the gutta-percha. Oil of melaleuca, pine needle oil, eucalyptol, and white pine oil partially dissolved the guttapercha. Results were statistically significant (p < 0.0001).
DISCUSSION The results indicate that rectified white turpentine may be a suitable alternative to chloroform and xylene for dissolving or softening gutta-percha. It is not carcinogenic and is biocompatible (6, 7). It is used as an expectorant, carminative, diuretic, and anthelmintic in a number of common pharmaceuticals (8, 9). Oil of melaleuca, pine needle oil, and white pine oil also may prove to be useful in softening gutta-percha. Moreover, they all have excellent biocompatibility (10). Rectified white turpentine, pine needle oil, and white pine oil are inexpensive and readily available in the United States as are 539
540
Kaplowitz
Journal of Endodontics
pine needle oil and oil of white pine. Eugenol, eucalyptol, and melaleuca are obtained from foreign sources and are more expensive. Dr. Kaplowitz is senior dental officer, U.S. Coast Guard Support Center Seattle, Seattle, WA and a former resident, Advanced Education Program in General Dentistry, Wilford Hall USAF Medical Center, Lackland Air Force Base, TX.
References 1. Brodin P, Roed A, Aars H, Orstavik D. Neurotoxic effects of root filling materials on rat phrenic nerve in vitro. J Dent Res 1982;61:1020-3. 2. U.S. Food and Drug Administration. Memorandum to state drug officials.
Washington, DC: U.S. Government Printing Office, 1974. 3. U.S. Food and Drug Administration. Chlorofrom, use as an ingredient (active or inactive) in drug products. Federal Register No. 26845. Washington, DC: U.S. Government Printing Office, 1974. 4. Fogiel M. The geometry problem solver: plane, solid, analytic. Piscataway, NJ: Research and Education Association, 1988:861-4. 5. Downing, D. Calculus: the easy way. 2nd ed. New York: Barron's Educational Series, 1982:189. 6. Damas J, Deflandre E. The mechanism of the anti-inflammatory effect of turpentine in the rat. Arch Pharmaco11985;327:143-52. 7. Damas J, Remacle-Volon G, Deflandre E Further studies of the mechanism of counter irritation by turpentine. Arch Pharmaco11986;332:196-202. 8. Tyler V. Pharmacognosy. 9th ed. Philadelphia: Lea & Febiger, 1988:110. 9. Hoover J (ed.). Remington's pharmaceutical sciences. 15th ed. Philadelphia: Mack Publishing Co., 1975:804. 10. The United States Pharmaceutical Convention. United States Pharmacopeia. 21st ed. Baltimore: The United States Pharmaceutical Convention, Inc. 1985:1562, 1587.