This section is from the book "Dental Medicine. A Manual Of Dental Materia Medica And Therapeutics", by Ferdinand J. S. Gorgas. Also available from Amazon: Dental Medicine.
Oil of cloves is obtained from the dried flower buds of the caryophyllus aromaticus, an evergreen tree, of the natural order Myrtacea - myrtle order - a native of the Indies.
The unexpanded buds are of a dark-brown color, with a yellowish red tint.
The oil is prepared by distilling cloves with water, to which common salt is added, in order to raise the temperature to the boiling point. It has a fragrant odor, and a hot, acrid taste.
Oil of cloves contains tannic acid, a pungent, volatile oil, resin, etc., and two substances - a hydro-carbon, caryophyllin, and an oxygenated oil, eugenol, called an acid on account of its possessing acid properties. Oil of cloves is an aromatic and powerful stimulant. Although it is a very fluid, clear and colorless preparation when fresh, it becomes yellow by exposure, and ultimately reddish-brown, with the odor of cloves, and a hot, aromatic taste. Like cloves, the oil acts less upon the system at large than on the part to which it is immediately applied. . Therapeutic Uses. - Oil of cloves is sometimes administered to relieve nausea and vomiting, to correct flatulence and excite digestion when languid: but its chief use is to modify the action of other medicines.
Of oil of cloves, gtt. ij to gtt. vj.
In dental practice, oil of cloves is employed to relieve odontalgia, in the form of a drop or two upon cotton, introduced into the carious cavity of a tooth; it obtunds the pain by an over-stimulating effect upon the irritable pulp. It is also employed for the same purpose in combination with other agents, such as morphia, sweet spirits of nitre, etc. When the use of creasote or carbolic acid is prohibited, owing to the patient's idiosyncrasy, the oil of cloves may be substituted.
The oil of cloves has also the effect of rendering creasote and carbolic acid more pleasant, without interfering with their action, being added in equal admixture. It is also employed very satisfactorily in the treatment of alveolar abscess, putrid pulps, being applied like creasote or carbolic acid, or combined with other agents.
Eugenol, C10H12O2, also called eugenic acid, is an active principle of oil of cloves, and is prepared by decomposing eugenate of potassium with sulphuric acid. It is in the form of a colorless oil, of the specific gravity of 1.076. Its odor resembles that of oil of cloves, and has a sharp, penetrating taste. It does not decompose at ordinary temperatures, and is not affected by exposure to the air. It is soluble in water and alcohol, but the aqueous solution is the more potent as a germicide. It is not poisonous, and when pure will coagulate albumen. For dental uses eugenol is of considerable value. When applied to exposed or partially exposed pulps of teeth it usually relieves the pain in from one to two minutes. For inflamed and congested pulps, it has been suggested to first apply a solution of borax and then eugenol. It also answers well as a dressing for root canals, especially after the removal of a recently devitalized pulp. In alveolar pyorrhaea, it is used in solution, 1 part of eugenol to 1000 of water, for the purpose of cleansing the pus pockets. In alveolar abscesses it has been suggested as an injection, after the use of peroxide of hydrogen, taking the precaution, in cases of abscesses with a fistulous tract, to seal the root at the apex. It has also been successfully employed in the treatment of benign tumors of the mouth, in the form of an injection of two drops.