radicular - refers to tooth root

radiograph - also known as an x-ray, image of bone and tooth structures produced through exposure to ionizing radiation

reimplantation - reinsertion of tooth into its socket following trauma that partially or completely removed it

reline - resurfacing of the tissue side of a removable denture to correct issue with fit

resin - material used in dental restorations and other dental treatments

resorption - loss of bone or structure

retainer - appliance used to ensure teeth do not return to prior misaligned state following orthodontic treatment

root - portion of the tooth that attaches the tooth into the gums and socket

root canal - pulp cavity inside the tooth root

root canal therapy - treatment of disease or injury to tooth pulp, generally involves the removal of part or all of the pulp and replacement with inert material

root planing - procedure used in the treatment of periodontal disease, involves deep cleaning of teeth at the roots to remove calculus and other substances

rubber dam - latex sheet used to isolate part of the mouth from saliva and potential contaminants during surgery