What Is Canine Guidance?
Mutually protected occlusion is also known as canine guidance or canine protected occlusion. It had its origin in the work of D’Amico 1961, Stuart 1959, Lucia 1962 and the members of The Gnathological Society.
Canine Guidance
According to this concept of occlusion, the overlap of the anterior teeth prevents the posterior teeth from making any contact on either the working or the nonworking sides during mandibular excursions. This separation from occlusion was named “dis-occlusion.”
What Is It?
In maximum intercuspation all posterior teeth are in contact with the forces being directed along their long root axes. The anterior teeth are very slightly out of contact, approximately 25 microns, relieving them of the horizontally directed forces.
As a result of the anterior teeth protecting the posterior teeth in all mandibular excursions and the posterior teeth protecting the anterior teeth at the intercuspal position, this type of occlusion came to be known as a mutually protected occlusion. This arrangement of occlusion is probably the most widely accepted because of its ease of fabrication and greater tolerance by patients.
The term morphologic occlusion is associated with the Angle classification of orthodontic relationship as based on the relationship of maxillary and mandibular first molars. If the mesiobuccal cusp of the maxillary first molar is aligned with the buccal groove of the mandibular first molar, an Angle Class I orthodontic relationship exists.
This is considered normal and is called the key of occlusion. The other 2 classes are distocclusion and malocclusion. Distocclusion occurs when the buccal groove of the mandibular first molar is positioned distally to the mesiobuccal cusp of the maxillary first molar. Mesio-occlusion occurs when the buccal groove of the mandibular first molar is positioned mesially to the mesiobuccal cusp of the maxillary first molar.
The ideal or perfect occlusion is based on the work of A. Filtchev for an optimum occlusion and includes the following criteria for an ideal occlusion. There must be an Angle Class I Neutrocclusion with multiple, strong, non-uniform contacts in centric occlusion and with the number and density increasing distally. During a laterotrusive position, this should show as a canine protected occlusion, group function or a bilaterally balanced occlusion.
During a protrusive position, there must be an edge to edge contact of anterior teeth and complete dis-occlusion of posterior teeth. Also there must be a coincidence of centric relation with centric occlusion.
Finally, no premature contacts and occlusal interferences, pathologic alterations in the periodontium, muscles and TMJ and an absence of occlusal trauma should be apparent. In general dental practice, for all new patients you must record the type of occlusion and make a note if canine guidance exists.