Which instrument is typically not used for subgingival scaling?

The correct answer highlights the use of instruments in periodontal therapy, specifically focusing on subgingival scaling. In this context, scalers are generally designed for supragingival use rather than subgingival scaling. They have sharp tips and are specifically shaped to remove deposits from the crown of the tooth above the gum line.

On the other hand, Gracey curettes and universal curettes are both designed with the capability to access and clean subgingival areas. Gracey curettes are specifically angled and tapered to adapt to the root surfaces, allowing for effective scaling and root planning in deeper pockets, while universal curettes have a design that allows for use on both anterior and posterior teeth.

Hand scalers may have limited functionality in deeper subgingival areas but are often designed for more efficient scaling work. Therefore, the choice of scaler as the instrument not typically used for subgingival scaling reflects the understanding that it is not intended for that specific area compared to the other instruments listed.