Assessment in Dental Orthopedics
Assessment in dental orthopedics can only be properly carried out when the evaluator has a clear understanding of ideal function. Assessment is an analysis compared to ideal. The following are long established, time tested principles of an ideal orthopedic relationship:
1. Open/close trajectory of mandible is a fair arc (no cross over patterns as seen on kinesiograph)-i.e. mandible opens and closes without displacement or torque
2. Speech and centric occlusion on same trajectory. i.e. skeletal positon coincidental with mandibular posturing musculature position. i.e. there is no musculo-skeletal discrepancy
3. Minimal overjet/overbite, end on end bites are optimum. Overbites create an excess range of motion in function (i.e. excess joint mobility in function; e.g. mandible has to advance for incising). Note: all primitive humans had an end on end bite. Because the TMJ can translate, does not mean that it is not stressed with overbites. TMJ translates least with an end on end bite.
4. Posterior guided occlusion is best. At the microscopic level posterior guided occlusion is necessary for condylar integrity. (see pgocclusion.com).
Dental Orthopedics Assessment
There are numerous structural and functional criteria that should be evaluated for proper assessment in dental orthopedics. All criteria should be met in a perfect dentofacial orthopedic relationship.
- Open and close on fair arc (best measured and documented on kinesiograph)
- Speech and biting on same trajectory (best measured and documented on kinesiograph)
- Arch development to Ponts
- Palpation of external auditory meatus for condylar head intrusion
- Proper tongue posture at rest and function
- Minimal freeway space at rest and function (1mm or less)
- Stable occlusion in centric occlusion. Simultaneous contact left and right, weighted on molars, no incline contacts. Best measured with poly-vinyl siloxane bite registration material held up to light for evaluation of translucent areas.