How many surfaces does a posterior filling typically cover?

A posterior filling generally covers two to four surfaces of a tooth, specifically addressing the cavities or decay that may occur on the existing surfaces. Posterior teeth, which include molars and premolars, typically have multiple surfaces—mesial, distal, buccal, and lingual. A filling in this region often requires restoration on more than one surface to effectively restore the tooth's structure and function.

When a cavity is present, it may extend across multiple surfaces, necessitating a filling that spans these areas to provide adequate protection and support for the tooth. For instance, a filling might cover the buccal and mesial surfaces if both are affected.

While some posterior fillings may, in rare instances, be limited to a single surface, it’s much more common for them to cover two or more surfaces due to the broader range of decay patterns and the design of posterior teeth. This is why the answer indicating two to four surfaces is the most accurate representation of typical posterior fillings.