Transcriber's Note. Italic text is denoted by _underscores_. [Illustration: THE ARCHIVES OF DENTISTRY] SUCCESSOR TO _Missouri Dental Journal, also Consolidated with New England Journal of Dentistry_. VOL. VII., NO. 4.] APRIL, 1890. [NEW SERIES. Societies. BLEACHING TEETH. BY DR. K. M. FULLERTON, CEDAR FALLS, IOWA. The bleaching of teeth has, from the first introduction of a positive method, been met with remarkable indifference and, at times, positive prejudice. Why this should be will remain a problem. The teeth that require bleaching belong mostly to a class condemned for all purposes except that of mastication. The process is generally only applicable to the six anterior teeth, while possibly an occasional bicuspid may be treated with advantage. When these anterior teeth, especially the incisors, are discolored, they are such a positive disfigurement that the operator has only the choice of evils—to bleach or to excise them, and insert an artificial crown. It would seem no difficult matter to come to a decision, or at least to determine to give the natural tooth a chance for future usefulness. The fear of re-discoloration, or annoying labor, should not be taken into consideration. All operators are liable to meet with sudden discoloration in the regulating of teeth by the strangulation of the pulp at the apical foramen. When this occurs, it is one of the most humiliating of accidents, as it is one of the most annoying to patients. Discoloration is caused by decomposition, through a slow disintegration of the organic material and the deposit of carbonaceous matter. It therefore follows that the products producing color are not _necessarily_ taken into the tubes by imbibition, though doubtless, to a limited extent, this is the case, but are produced by local degeneration through putrefactive processes. This change, though very slow in producing results, eventually gives to the tooth the bluish tinge, or to a tooth long affected by decomposed matter, the dirty, bluish-yellow. It is unnecessary to enter minutely into the more remote causes of discoloration, but we may summarize them as follows: 1st. When death of a tooth is caused by a blow, attacks of caries, too rapid pressure in regulating teeth, etc., the death and devitalization are followed by imbibition of coloring matter through the largest diameter of the tubules and local discoloration of the tube contents in the minuter anastomosing conduits. These changes may occur in teeth affected by caries, or without any external evidence of disease. 2d. The more aggravated cases, when this color has changed to a bluish-yellow, involving the entire structure of the dentine. 3d. Of the latter class, there may be a further subdivision, in which these are complicated with periosteal lesions which more or less interfere with efforts at restoration to original color.