coronal polishing certification: Everything you need to know. Coronal polishing is a dental procedure that involves the removal of plaque, tartar, and stains from the teeth using a polishing instrument and a special polishing paste. Dental hygienists and dental assistants may perform coronal polishing as part of their duties, but many states require them to hold a coronal polishing certification in order to do so. And if you want to start your career in...