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.
Iodoform is a preparation of iodine, being obtained by the action of chlorinated lime upon an alcoholic solution of iodide of potassium, heated at 1040 F., the product being iodoform and iodate of lime, the iodoform being separated by boiling alcohol. It is in the form of small, pearly crystals, of a yellow color, with an unpleasant odor, like that of saffron, and a sweetish taste, and soft to the touch. It is volatile, and soluble in alcohol, chloroform, ether and the fixed and volatile oils, but insoluble in water.
Iodoform has no irritant action, and, in small doses is tonic, stimulant, anodyne, alterative and disinfectant, having great influence on the nervous system; it is also antiseptic, but is not a germicide, and although its germicidal action is practically nothing, it is extensively used in surgical practice. Its good effects upon the tissues of wounds are due to its protecting power both mechanically and by the dryness it maintains, when it is applied in the form of a powder.
Although it will not destroy micro-organisms, yet it will destroy the toxic substances formed by micro-organisms. In large doses, it causes a form of intoxication, followed by convulsions and fatal effects. In the form of vapor, it possesses anaesthetic properties, but not equal to those of the general anaesthetics in common use. It has also been used as a local anaesthetic, and also as an antiseptic. Its odor can be detected in the blood, the brain and the muscles.
Iodoform produces the constitutional effects of iodine, but is chiefly used externally for painful cancerous and phagedenic ulcerations, irritable ulcers, ill-conditioned wounds, obstinate skin diseases, scrofulous glandular enlargements, to allay the pain of gout and neuralgia, and for phthisis, mixed with starch and spread on paper, so that the vapor may be inhaled. Dusted over a diseased surface, it allays pain and changes the morbid action. A saturated solution of iodoform in chloroform is recommended for neuralgia; also a saturated solution in any of the essential oils is used for the same affection. In the form of an ointment, it is used as an application to irritable ulcers. For ulcerated surfaces, it may be sprinkled over the part, and lint, coated with glycerine, applied as a dressing.
Of iodoform, gr. j to gr. iij, three times a day, in the form of a pill.
Iodoform is highly recommended in dental practice not only as an antiseptic but as an anaesthetic, either alone, or what is better, combined with eucalyptus oil. It possesses no escharotic property sufficient to cause irritation or the destruction of parts. In the treatment of alveolar abscess, iodoform, in combination with oil of eucalyptus, has given great satisfaction; also in cases of putrescent pulps applied as an injection. It is recommended to be used as follows: First, an injection of eucalyptus oil, followed by the introduction of the mixture of iodoform and eucalyptus into the root canal, on cotton, or on a strand of floss-silk, which is charged by first dipping it into the oil, and then into the iodoform; or the two may be combined in a solution (see Eucalyptus), and in this form introduced into the sac or root canal. Dr. C. N. Peirce recommends iodoform ground up with equal parts of oil of cloves and oil of eucalyptus, which forms a substance of a soft cheesy consistence, a portion of which can be introduced to the inflamed part, on the point of a small broach. Iodoform is also a very serviceable application in alveolar pyorrhoea. A saturated solution in eucalyptus oil is also serviceable as an external application in neuralgia. Iodoform is also employed as an anodyne, for the relief of the pain following the extraction of teeth affected with periodontitis, and alveolar abscess; also as an injection in diseases of the antrum, and as a packing for the pus pockets in alveolar pyrrhaea, for which purpose it is often combined with oil of eucalyptus, or oil of cinnamon. Also for filling the canals of pulpless teeth, for which purpose a paste of iodoform and carbolic acid is used, and allowed to remain for a few days, and, if no soreness follows, a permanent root-filling can then be introduced. When iodoform is used alone, a pellet of cotton or a strand of floss-silk may be dipped into glycerine, and the iodoform be thus taken up. Dr. Francis Peabody recommended the application of the vapor of crystals of non-agglu-tinized iodoform for treating pulpless and diseased teeth, blind abscesses, etc. The cylinder of a hot-air syringe is partly filled with the crystals, and heated over an alcohol flame or gas jet until the crystals are fused. The syringe point is then placed in the root and the bulb compressed, forcing the vapor of iodoform into the canal, every part of which it permeates, the tubili being filled throughout, and a precipitate deposited, forming a solid, insoluble filling. The vapor penetrates the apical foramen and comes in contact with the peridental membrane subduing irritation and inflammation, gradually restoring the tooth, and if loose, rendering it firm in its aveolus. To disguise the unpleasant odor of iodoform, it may be incorporated with a little oil of rose, as one drop of the oil will remove the odor of half a drachm of iodoform; the odor is also disguised by balsam of Peru, oil of cinnamon, oil of lavender, or oil of sassafras. Three grains of cumurin (a derivative of the Tonka bean) will disguise the odor of one drachm of iodoform; or the addition of attar of rose, one minim to the drachm; or of essence of rose geranium, three or four minims to the drachm. Creolin is also a very good deodorizer of iodoform; also aqua heliotrope, for the hands also, one or two drops of creasote or carbolic acid to the ounce of iodoform, is also recommended. According to some, it is not a matter of indifference whether iodoform be applied as a dressing for wounds and ulcers, in the form of crystals, as amorphous powder dissolved in ether or as an ointment. Iodoform acts not only as a chemical combination, allowing the escape of iodine in a free state, but it has certain mechanical properties. When the surface of an ulcer or wound is covered with a layer of iodoform in crystals, a certain degree of absorption of the fluids secreted takes place. These products of secretion penetrating the interstices between the minute crystals of iodoform soon lose the liquid form, and produce with them an impermeable crust. Under this crust cicatrization soon occurs, without any retraction of the tissues; hence they suppose that the best form in which to employ iodoform for ulcers and wounds is that of the crystals. As toxic effects have followed the internal administration of iodoform, it should be prescribed with care, and also the application of it to extensive surfaces should be avoided. The toxic symptoms have been manifested as follows, the maximum dose which caused them in a certain case being 12 1/2 grains: