FIG. 67.
Crescent-shaped, bitubercular, and tribucular as well as deformed teeth, tend to be cone-shaped. The malformation of these teeth results from precongenital trophic change in dentine development, dwarfing and notching the cutting and grinding edges of the second set of teeth, of which a familiar example is the so-called Hutchinson’s teeth, usually referred to a syphilitic causation. Hutchinson’s position has, however, been more strongly stated than his words justify, since he admits that in at least one-tenth of the cases this cause could be excluded.
Syphilis only plays the part of a diathetic state profoundly affecting the maternal constitution at the time of dentine development; while these teeth may be due to secondary results of syphilis, they do not demonstrate syphilitic heredity.
In Fig. [67] are seen the teeth of an individual affected with constitutional disease (referring to Fig. [51] it becomes evident that the defective lines represent the respective ages, 2½, 4, and 5 years). The degree of pitting will depend, as a rule, on the severity of the constitutional disorder. In the case just cited, however, although nutrition was but slightly disordered, each tooth shows a tendency to conate. Not infrequently cavities extend completely through the tooth. The cusps of the (permanent) first molars, calcifying at the first year, are usually attacked also, and arrested in development, producing the cone shape. These data, together with the dates of eruption of the temporary and permanent teeth, furnish an absolute basis for calculation as to malnutrition producing excessive or arrested development, not only of the teeth and jaws but all parts of the body.
FIG. 68.
