0099-2399/91]1706-0280/$03.00/0 JOURNAL OF ENDODONTICS Copyright 9 1991 by The American Association of Endodontists
Printed in U.S.A.
VOL. 17, NO. 6, JUNE1991
The Effect of Essential Oil Type on the Setting Time of Grossman's Sealer and Roth Root Canal Cement Gary L. Kaplowitz, DDS, MA, MEd
pimento; group 3 was Grossman's and oil of Melaleuca; group 4 consisted of Roth and eugenol; group 5 was Roth and oil of Melaleuca; and group 6 consisted of Roth and oil of pimento. A new mixture of the powder and liquid component was prepared for each sample. Each sample mix consisted of 0.1 g of powder and 0.03 g of essential oil. The powder and liquid components were mixed on a glass slide and were delivered with a round-end periodontal probe to a bore hole (1.50 m m deep x 1.25 mm in diameter) drilled in the root surface of an extracted molar. After the mixture was transferred to the bore hole, the sample was stored in an incubator at 37~ and 100% humidity. Two different regimens were used for determining setting time in accordance with results obtained in pilot studies. Groups 1 and 2 were monitored every 15 min. Groups 3, 4, 5, and 6 were monitored at 12-h intervals. A modified hand-held Gilmore needle was used to determine setting time. The needle weighed 50 g, and the diameter of the tip was 1.06 mm. If the needle pierced the surface or produced an indentation, the sample was considered unset. If no indentation was produced in the surface, the sample was considered to have set. Data were divided into two sets on the basis of the time interval used to measure setting time. Groups 1 and 2 were measured in minutes and were grouped together. Groups 3 through 6 were measured in days and were grouped together. Data for groups 1 and 2 were analyzed with by Student's t test. The data for groups 3 through 6 were analyzed with a one-way analysis of variance and a post hoc Tukey's honestly significant difference test.
Setting times were determined for mixtures consisting of the powder components of Grossman's sealer or Roth root canal cement with either eugenol, oil of pimento or oil of Melaleuca. The powder component of Grossman's sealer, when mixed with eugenol or oil of pimento, had a significantly shorter setting time than did the powder component of Grossman's sealer mixed with oil of Melaleuca or Roth root canal cement mixed with eugenol, oil of pimento, or oil of Melaleuca.
Obturation of the root canal space is achieved most commonly with a solid core of gutta-percha supplemented with a zinc oxide-eugenol root canal sealer. However, eugenol can provoke inflammation and necrosis in the pefiapical tissue (1, 2). Eugenol also blocks nerve transmission (3) and can provoke an allergic reaction (4). Other essential oils with comparable or improved biocompatibility might be used in place of eugenol in the liquid component of root canal sealers. For example, oil of Melaleuca has been used in the cleansing of open surgical wounds (5) and the treatment of trichonomal vaginitis (6). Oil of pimento has demonstrated less irritation potential than eugenol when injected subcutaneously (2). The setting time of the powder component of a zinc oxide root canal sealer when mixed with eugenol or oil of Pimento has been measured (7). However, the regimen for testing the setting time was not rigidly followed. The setting time of oil of Melaleuca, when mixed with the powder component of a zinc oxide sealer, has never been measured. The purpose of this study was to determine the setting time of Grossman's sealer and Roth root canal cement when each was mixed with eugenol, oil of pimento, or oil of Melaleuca.
RESULTS Setting times for all groups are presented in Table 1. Because the setting times of groups 1 and 2 were measured in minutes, whereas the setting times for groups 3 through 6 were measured in days, no statistical analysis was required to establish that there was a significant difference between these two sets of data. A Student's t test established that there was a statistically significant difference between the setting times of groups 1 and 2 (F = 2.83, t = 2.11, p < .05). The data for groups 3 through 6 were analyzed with a oneway analysis of variance which demonstrated significant differences among the four groups (p < 0.0001). A post hoc
M A T E R I A L S AND M E T H O D S Six experimental groups consisting of 10 samples per group were prepared. Each group consisted of either Grossman's sealer (Endoco, Memphis, TN) or Roth root canal cement (Roth Drug Co., Chicago, IL) mixed with one essential oil (Lorann Oils, Lansing, MI). Group l consisted of Grossman's and eugenol; group 2 consisted of Grossman's and oil of
Vol. 17, No. 6, June 1991
TABLE 1. Time required to achieve final set Time Group
1 2 3 4 5 6
94.5 111.0 8.7 11.5 12.8 15.4
min min days days days days
Minimum 75.0 105.0 7.0 10.0 12.0 15.0
min min days days days days
Maximum 120.0 150.0 11.0 13.0 14.0 16.0
min min days days days days
21.3 12.6 1.8 1.1 0.8 0.5
Tukey's (a) analysis established that all four groups were significantly different from each other (p < 0.05). The rank order of groups is presented in Table 1. For example, group 3 required significantly less time to set than did groups 4, 5, and 6 but required significantly more time to set than did groups 1 and 2.
obtained values (7). Because the mean setting times for both mixtures were less than 2 h, the difference may not be clinically significant. The results of this study demonstrate that essential oils, other than eugenol, may have a role in the liquid component of root canal sealers. Oil of pimento has already demonstrated greater biocompatibility than eugenol (2). Although the setting time of oil of Melaleuca, when mixed with either Roth or Grossman's powder, was prolonged, the addition of catalysts or modifiers may result in reduced setting time. This study is of heuristic value in that it establishes the potential of other essential oils, with enhanced biological or physical properties, to supplant eugenol in the liquid component of root canal cements. Dr. Kapiowitz is a Commander in the United States Public Health Service and a Senior Dental Officer at the United States Coast Guard Support Center, Seattle, WA. Address requests for reprints to Dr. Gary J. Kaplowitz, United States Coast Guard Support Center, 1519 Alaskan Way South, Seattle, WA 98134-1192.
DISCUSSION The results of this study demonstrate that the setting time for Grossman's sealer, when mixed with eugenol, is significantly less than that for Roth root canal cement when mixed with eugenol. Grossman's sealer requires approximately 2 h for complete set whereas Roth root canal cement requires approximately 2 weeks. However, the clinical significance of this difference is unknown. Eugenol, when mixed with Grossman's sealer powder, achieved a more rapid set than when the powder was mixed with oil of pimento or oil of Melaleuca. The setting times for eugenol and oil of pimento were comparable to previously
References 1. Tagger M, Tagger E. Subcutaneous reaction to implantation of tubes with AH-26 and Grossman's sealer. Oral Surg 1986;62:434-9. 2. Grossman L, Lally E. Assessment of irritation potential of essential oils for root canal cement. J Endodon 1982;8:208-13. 3. Kozam G. The effect of eugenol on nerve transmission. Oral Surg 1977;44:799-805. 4. Barkin M, Boyd J, Cohen S. Acute allergic reaction to eugenol. Oral Surg 1984;57:441-5. 5. Humphrey M. A new Australian germicide. Med J Aust 1930;1:417. 6. Pena E. Melaleuca alternifolia oil: its uses for trichonomal vaginitis and other vaginal infections. Obstet Gyneco11962;19:793-7. 7. Grossman L. Setting time of selected essential oils with a standard root canal cement powder. J Endodon 1982;8:277-81.
You Might Be Interested to Know Atropine, a sometime antisialogogue in dentistry, is often used to dilate the pupil for eye examinations. This latter characteristic accounts for the Latin name of the plant genus from which it is obtained, Belladonna. In ancient Egypt, large, dark eyes were considered a mark of beauty in women. A woman not naturally endowed with this feature could affect the look by adding extract from a certain plant into her eye shadow. The atropine in the extract would diffuse into the eyes to cause excessive pupillary dilation, rendering her a "beautiful woman," i.e., bella donna. John Smith