Which instrument is primarily used for heavier calculus deposits?

The hand scaler is specifically designed to effectively remove heavier calculus deposits from the tooth surfaces. This instrument typically features a sharp, pointed working end that can reach into the interproximal areas and make direct contact with the thick calculus. The design and sharpness of the blade allow for effective scraping and scaling of deposits, facilitating the removal of larger pieces of calculus that may be difficult to manage with finer instruments.

In contrast, while other instruments like the Gracey curette and universal curette are valuable for calculus removal, they are generally more suited for lighter deposits or for specific areas of the mouth. The Gracey curette is designed with a specific angulation for root surfaces and softer deposits, making it more specialized, while the universal curette can be used universally on different tooth surfaces but may not be as effective as a hand scaler when dealing with substantial calculus. The periodontal probe, on the other hand, is primarily an assessment tool used to measure pocket depths and is not designed for debridement or calculus removal. Thus, the hand scaler's design and intended use make it the preferred choice for handling heavier calculus deposits.