Which of the following statements is true regarding hand curettes?

Hand curettes are versatile instruments designed for the removal of dental deposits and debridement in periodontal therapy. The statement that hand curettes can be adapted for both supragingival and subgingival use is accurate because they are specifically shaped to access both areas effectively.

The blade of a curette is rounded, which allows it to be inserted into the gingival sulcus without causing damage to the surrounding tissues. This adaptability makes curettes useful for scaling both above the gum line (supragingival) and below the gum line (subgingival), where different techniques may be applied depending on the clinical situation.

The other statements do not accurately describe the function of curettes. They are not exclusively for polishing teeth, which is the role of other instruments such as prophy angles. While some may believe that curettes can only be used on supragingival surfaces, this is limiting and does not reflect their true functional capacity. Additionally, their primary purpose is not just for diagnostic use, as they are actively used in therapeutic procedures rather than merely for examination.