When should a patient be advised to avoid food after coronal polishing?

After coronal polishing, it is recommended that a patient avoid food for at least 30 minutes. This time frame allows any fluoride treatment applied to fully adhere and provide maximum benefit to the tooth enamel. Following polishing, the surface of the teeth is often more porous, which means it can absorb substances readily. Eating too soon may wash away the fluoride and hinder its effectiveness.

This specific length of time is a balance between allowing the fluoride to be effective without unnecessarily prohibiting the patient from eating for too long. Other timeframes may not be appropriate since they either do not allow sufficient time for the treatment to work or impose an inconvenience that could deter patients from returning for regular care.