What is the primary function of a straight chisel in cavity preparation?

The primary function of a straight chisel in cavity preparation is to plane and cleave enamel. This tool is specifically designed with a sharp edge that allows dental professionals to create precise cuts and smooth surfaces in enamel. By planing the enamel, the straight chisel can help shape cavity walls and make them more suitable for restorative procedures, ensuring that the restoration fits well and is adequately retained.

This action is particularly important during cavity preparation, as it allows clinicians to achieve the desired contour and angle of the tooth surface. The ability to cleave the enamel also aids in removing any irregularities, producing a clean working area for subsequent restorative materials.

The other options refer to functions that are performed with different instruments or techniques. For instance, while the removal of carious dentin is an important aspect of cavity preparation, this function is typically performed with other dental instruments such as excavators or handpieces. Beveling cervical walls is also usually done with a different type of tool, such as a handpiece or a specific bur, to provide additional retention. Administering local anesthetics is a procedure that requires syringes and needles, not a chisel, reinforcing that each dental instrument has a specialized purpose tailored to different aspects of dental care.