The influence of design factors on the performance of the inverted cone bur.

THE advent of cavity-shaping technics, which utilize high rotational speeds and a light hand pressure to remove a large amount of tooth material, has resulted in an acute awareness by dental operators that certain burs are superior to others. This situation has caused an obvious desire by the dentist, the dental researcher and the manufacturer for knowledge which will explain these differences in cutting ability. This report is a partial result of a program to determine the influence of various design factors on the performance of dental burs. The actual cutting ability of a bur depends on two qualities, (1) the true cutting ability and (2) any clogging tendencies. This program was designed to study the first quality while eliminating the second as much as possible. For this reason the inverted cone bur with its short length of engagement has been chosen for specific study. Dental bur manufacturers are faced with a very difficult problem; namely, the inexpensive production of a bur with keen sharp flutes. They can produce better burs than are available at the dental supply stores. However, the cost would be considerably higher than the present market price, so as to be economically unfeasible. This is particularly true in the production of steel burs. It is, therefore, the intent of this program to help them, in conjunction with these research departments, produce for the dental operator as good a bur as possible, while remaining within economic limits.