What does light pressure during polishing do to the edges of the polishing cup?

Using light pressure during polishing causes the edges of the polishing cup to flare slightly, enhancing the effectiveness of the polishing process. This flaring action allows the cup to adapt better to the contours of the tooth surface, facilitating a more even distribution of the polishing material. It also helps to minimize the risk of damaging the tooth enamel and enhances the smoothness achieved after polishing.

When the edges flare, they create a greater surface area for contact with the tooth, allowing for a gentler polish that can effectively remove surface stains and debris while preserving the integrity of the enamel. In contrast, heavy pressure would flatten the edges or cause them to become rigid, which could inhibit their ability to effectively polish the tooth surface and prevent damage during the procedure.