Dental tooth bur

Abstract

A dental tooth bur includes a plurality of flutes longitudinally disposed at one end of a shank and adapted to produce a prepared cavity having a wall that has a plurality of generally microretentive ridges in its lower portion and that is generally smooth in its upper portion. The microretentive ridges in the lower portion of the wall assist in the positive retention of the material used to fill the cavity, while the generally smooth upper portion prevents microfracturing of the tooth enamel and/or filling material resulting from mastication pressure. Each of the flutes includes a cutting edge having a plurality of recesses in its lower portion and a nonrecessed area in its upper portion. The recesses produce the ridges in the cavity wall. The flute design allows the simultaneous smooth surfacing of the upper portion of the wall and the production of the ridges in the lower portion of the wall. The ratios of the recessed and nonrecessed areas of the cutting edges of the flutes may vary as desired. Each of the flutes may be provided with a radiused edge joining the cavity wall cutting edge with a cutting edge for the bottom surface of the cavity. This radiused edge produces a cavity preparation having a smooth transition rom the cavity wall to the cavity floor. This relieves the internal stress points and sharp line angles in the cavity preparation and reduces the possibility of future tooth fracture at the juncture of the cavity wall and cavity floor.

Dependencies are inferred from the claim text.