The invention relates to an instrument for dental use, of the type comprising a handle and one or two active ends that are pointed or variously shaped for use in various types of procedures, and in particular to a specific type of finish on the handle and a method of forming the finish.
Currently known instruments of this type have a handle of which a portion has a knurled or ridged surface, in particular a knurled surface with deep indentations. The portion of the surface machined in this way is currently thought to be necessary to enable the dentist to have a firm grip on the instrument.
The knurling, while considered necessary for gripping the instrument, has proved to be a source of major disadvantages, particularly with regard to hygiene. The indentations in the knurled surface trap contaminants and dirt that could transmit microorganisms. Although they are sterilized, instruments of this type may not be perfectly cleaned because contaminants can accumulate in the indentations in the knurled surface.
The primary object of the present invention is a surgical instrument, particularly intended for dental use and method of making same, which does not have the above disadvantages but nevertheless still has the advantage of enabling the dentist to grip the instrument correctly and firmly.
The instrument according to the present invention is substantially characterized in that the handle is substantially smooth and has at least one grip zone which has a plurality of microchannels extending in a circumferential direction of the handle. The plurality of microchannels form a uniform surface roughness with the microchannels being arranged on the handle in a uniform random distribution. Each of the micro-channels are sized to be below a magnitude to collect contaminants. The grip zone is formed by providing a grinding surface with a magnitude of roughness that is below a roughness to cause indentations in the handle that would collect contaminants. A grinding surface in the form sandpaper having a grade or sieve number between n. 105 and 500 of the US standard sieves scale is used to create the micro-channels. Sandpaper of n. 240 grade has been found to the most desirable. Other grinding surfaces and other devices can also be used which form the same type of uniform random distribution of microchannels as formed by sandpaper having a grade between n. 105 and n. 500 of the US standard sieves scale. The functional element of the instrument is connected to one of the ends of the handle for performing a dental procedure. The grinding surface is rotated relative to an outer surface of the handle and the handle is held against the grinding surface to form micro-channels in the handle. The relative rotating has a directional component in a circumferential direction of the handle. The micro-channels thus formed are of a size being below a magnitude to collect contaminants. The relative rotating forms the micro-channels in the circumferential direction of the handle.
Alternatively, the outer surface of the handle is also moved against the grinding surface in an axial direction of the handle to also form the micro-channels in the handle. The axial moving is performed substantially simultaneously with the relative rotating to form the micro-channels in both the circumferential direction and the axial direction of the handle. This causes the micro-channels to be formed in a helicoidal direction of the handle.
This type of grip surface provides sufficient roughness to ensure that the user can grip it correctly, and that there is no need for indentations, cavities or other forms of uneven surface that could trap contaminants or pathogens. In the context of the present description the grinding surface covers any surface or device which forms a uniform random distribution of microchannels as formed by sandpaper having a grade between n. 104 and n. 500 of the US standard sieves scale. This size and distribution has been found to allow sufficient roughness to be obtained without the formation of indentations which could form a trap for contaminants or pathogens.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.