At what handpiece speed is sufficient to remove stains during a mechanical polish?

In the context of dental handpieces, mechanical polishing typically requires a specific range of speeds and pressures to effectively remove stains from teeth without causing damage to the enamel. The correct answer indicating 20 psi is significant because this pressure level provides an optimal balance for achieving efficient stain removal while maintaining patient safety and comfort.

At 20 psi, the handpiece operates with enough force to effectively engage the polishing cup with the surface of the tooth, facilitating the removal of extrinsic stains like those from coffee, tea, or tobacco. This pressure enables the polishing agents to work effectively without causing excessive friction or heat, which could lead to discomfort or damage to the tooth structure.

In contrast, other pressures like 15 psi may not provide enough force for effective stain removal, while higher pressures like 30 psi or 40 psi increase the risk of abrasion to the tooth's surface and may not significantly enhance the polishing effect. Therefore, the selection of 20 psi balances efficiency with safety, making it the preferred choice for mechanical polishing tasks in a dental setting.