所謂楔状欠損の観察とその成因に関する実驗的研究 (3)

Abstract

1. Generally speaking the rubbing is an indispensable factor to cause a so-called cuneiform defect. This defect occuring on the enamel, however, is caused not only by rubbing but by acquired decalcification, process of dental caries and congenital reduction of resistance, such as less calcification. On the other hand, that on the cervical area is mainly due to rubbing and decalcification by acid or dental caries plays a smaller part in this case.2. Principal cause of the cuneiform defect is the use of tooth-bruch and tooth-powder, especially being concerned in the quality of the latter.3. So-called cuneiform defect occurs by all sorts of movement of tooth-brush, such as vertical, horizontal and round movement, but above all the effect of horizontal movement is important.4. Furthermore it can be noticed by the other causes: fingertip and tooth-powder, salt, toothpick, the margin of dental plate, clasp of dental plate, raw vegetables, fruits, and all kinds of thread.5. The degree and the form of so-called cuneiform defect have some connection with force, direction and working period of rubbing, quantity of applied tooth-powder, size and strength of the brush, width of the exposed root surface, hardness of the tooth-root and speed of the gingival atrophy.