Depending on your specific treatment, some of the movements may require either “attachments” or “ridges” to help the aligner grip the teeth. These bumps, or wells, are where the aligner grips the attachment the doctor places on your teeth. The attachments are actually small pieces of composite the doctor affixes to your teeth that are then gripped by bumps on your aligners. The ridges are slim indentations in your aligners. Your doctor will use one or both of these features to attempt to achieve the desired movement.