Formula

Na2So3+7H2O.

Derivation

Sulphite of Soda is prepared by passing sulphurous acid into a solution of carbonate of soda, and evaporating free from air. The sulphurous acid unites with the soda of the carbonate, to form the sulphite of soda, and the carbonic acid escapes. On cooling, the salt crystallizes in white prismatic crystals, and should be kept well stoppered, as it changes on exposure into sulphate of soda.

Medical Properties And Action

Sulphite of soda is a disinfectant and deodorizer, and its action and uses are similar to those of the other sulphites, hyposulphites and sulphurous acid.

Dose

Of sulphite of soda, gr. xv to Dose 1445 three times a day.

Dental Uses

Sulphite of soda is sometimes employed in the form of a lotion for aphthous sore mouth due to a parasitic vegetable ; also in ulcerous stomatitis, gangrenous stomatitis, and all suppurative affections of mucous membrane, especially when they are sustained by zymotic influences or invisible organisms. Dr. E. C. Kirk has successfully employed sulphite of soda in combination with boracic acid, for bleaching discolored teeth. (See Formula.) His method is as follows:

Having adjusted the rubber dam to the tooth to be treated, and one adjoining it on each side, the cavity of decay is cleansed of all debris and the root filled with gold or gutta percha for one-half its length. The powder, composed of sulphite of soda and boracic acid, is packed into the remaining portion of the pulp canal and cavity of decay, leaving just sufficient space to insert a temporary filling of gutta percha or Hill's Stopping. After the powder has been properly packed, a drop of water is permitted to fall upon it from a drop-tube or a pellet of cotton wrapped around a broach, the object being to dampen the powder, not to wash it out. The cavity of decay is then filled with gutta percha, and the patient dismissed until the next sitting, when a second application can be made, which is usually sufficient, except in cases where the walls of the tooth are very thick and much discolored, when a third application may be necessary. When the water is added to the powder a chemical reaction takes place, the boracic acid unites with the sodium of the sulphite to form sodium borate, at the same time liberating the sulphurous acid, upon which the bleaching power depends. Dr. F. D. Weisse recommends hyposulphite of soda for abscess of the antrum, the following solution being injected at least five times a day: Sulphite of soda, one drachm to one ounce of water.

Dental Formulae

For Aphthous Sore Mouth.

Sodii sulphitis .... Aquae.......

Signa

Apply as a lotion.

Signa 1446Signa 1447

For Same.

Dr. Wallace.

Sodii sulphitis . . . gr.xxx

Glycerinae,

Aquae......aa

Signa

To be used on a swab every two hours.

Signa 1448Signa 1449

For Bleaching Discolored Teeth.

Dr. E. C. Kirk.

Sodii Sulphitis...............gr.100

Acidi boracis...............gr. 70

Mix by grinding together in a warm, dry mortar, to a fine powder, which is preserved in an air-tight stoppered bottle, and kept in a dry place.

Signa

(See Dental Uses of Sulphite of Soda.)

Signa 1450