In periodontal scalers and curettes, the blade is formed by which two surfaces?

In periodontal scalers and curettes, the blade is primarily formed by the lateral surface and the face. The lateral surface refers to the sides of the blade that come into contact with the tooth surface during scaling or root planing. The face is the flat, broad surface that forms the cutting edge of the instrument when combined with the lateral surface. This configuration allows for effective removal of calculus and plaque from teeth and root surfaces.

The other options include additional parts of the instrument, such as the back and shank, which do not form the blade itself. The back is typically rounded and not used for cutting, while the shank connects the working end to the handle but does not contribute to the blade's structure. Understanding the anatomy of these instruments is crucial for proper usage and technique in periodontal therapy.