THE ROTH PHILOSOPHY
If one were to choose one phrase to describe the philosophy of the late Dr Ronald Roth it would be summed up by the phrase:
CLEARLY DEFINED TREATMENT GOALS
Establishing clear treatment goals increases diagnostic ability thus reducing the risk of treatment failure. Treatment failures are often thought to be due to poor cooperation or incorrect wire /brace selection. Not True!!! Misdiagnosis is the usual culprit.
A failed orthodontic result can take the form of TMJ symptoms, instability, worn teeth, periodontal decline, or facilal balance decline. Dr Roth regarded condylar displacement as a major factor in contributing to unstable results. Condylar displacement means that when a patient bites their teeth together the condyle comes out of the fossa . The result is that problems will arise. The timeline of when these problems occur will vary… but they will occur. Dr Roth used to say that you find out the "fruits of your orthodontic labor 10 years after the treatment is complete." Any change in the temporomandibular joints has a direct effect on the occlusal relationship between the upper and lower teeth. Thus correct mandibular position / condyle -fossa relationship is one of the five treatment goals.
Dr Roth said we must have goals for all areas influenced by orthodontic treatment. Roughly these can be divided into Five Areas:
HEALTHY TMJ (CORRECT CONDYLAR -FOSSA RELATIONSHIP).
We have touched upon the importance of the condylar postion as a goal. To reiterate: The goal is to have the teeth hit simultaneously when the condyle is seated in an anterior superior postion on the disc centererd transversely. The condyles and the discs move together down the eminentia from their uppermost position in the fossae as the jaw opens. If disc displacement is complete or even partial the disc, condyle, and fossa undergo degenerative changes. This results in a change of how the condyle moves which, together with changes in jaw position result in adverse changes to the profile (ie the mandible appears to drop backwards and an open bite.)
When we have clear cut goals for facial esthetics we can choose tooth movements, wires and the extraction decision to move in that direction. Talking with the family or the patient about facial harmony (as well as the other goals) allow the topic of Jaw surgery to be freely discussed.
One of the most common things seen is a facial asymmetry as viewed when looking at the patient from the front. These asymmetries are closely related to TMJ status, occlusal function tooth alignment and esthetics.
Dental esthetics and facial esthetics are mutually complementary. If we are to achieve proper esthetics AND proper functional occlusion we may need you, the restorative dentist to recreate the anatomical crown length that was present before the patient parafunctioned 20% to 30% away!
It seems that the profession has forgotten that most patients need 3-4 mm of vertical overlap (overbite) of the anterior teeth to provide adequate disclusion of the posterior teeth in functional movements. Additionally the Canines need a mesial inclination to allow proper mandibular movement laterally.
The periodontium that supports the teeth needs an adequate thickness. If teeth are excessively flared buccally or labially the risk for recession increases. Currently there is a trend that implies that fitting all of the teeth in the arches (non extraction therapy) results in reaching ideal all of the goals listed above. This is not true. Dr Roth proposed his philosophy was based on specific goals in each of the areas discussed above. Non extraction is a treatment modality…. It should NOT be a philosophy of care!
I would like to thank Dr Kazumi Ikeda for the use of his material in this brief overview.