A contemporary and evidence-based view of canine protected occlusion.

Dentists and orthodontists at one time or another have been exposed to the gnathological concept of occlusion. Certainly, a well-known and advocated precept of gnathology is that of “canine (mutually) protected occlusion (CPO).” The basic premise of CPO is that, on laterotrusive movements of the mandible, only the canines (possibly first premolars) contact and therefore protect the remaining dentition from adverse occlusal torsion forces on contacts to and from centric occlusion (and/or centric relation). Furthermore, it is contended that CPO is the optimal (ideal) type of functional occlusion for the natural dentition vis-à-vis dentures and is the functional occlusion type toward which restorative and orthodontic treatments should be directed. It is also argued that orthodontists who do not obtain canine protected functional occlusions are doing a disservice to their patients and possibly not practicing state-of-the-art orthodontics. That is, gnathologists maintain that orthodontists who do not establish a gnathologic finish, including CPO, potentially predispose patients to temporomandibular disorders (TMD) and orthodontic tooth relapse. However, many past notions in dentistry and orthodontics, particularly related to gnathology, have not withstood the test of time or the rigors of science. And, with the recent emphasis for dentists to practice evidence-based decision making, it makes sense to fully investigate and evaluate the concept of CPO. The purpose of this article is to discuss past and present knowledge and information on the general topic of functional occlusion (particularly regarding CPO and orthodontics) and relate it to logical considerations