Skeletal assessment.
Its important to anaylse the patients skeletal pattern. In laymans terms we need to assess the mandibular position relative to the maxilla. A class 1 patient will present with a mandible in the correct position. The easiest way to tell this is from a profile photo. A straight line drawn downwards from the philtrum of the lip will end up touching the tip of the chin. A class 11 patient presents with a retrognathic mandible ie reduced prominance of the chin and a class 111 patient will present with a prominant chin. Its a good general rule to assume that the classification of the dentition will follow the classification of the skeletal pattern. We need to be careful to address the main complaint of the patient. If the patient complains about the facial profile then we need to realise that the only way we can change this is with orthognathic surgery (unless its exaggerated buy a anterior mandiblular posture that the patient has developed because of an anterior crossbite or posterior interferance).
Assessing the dentition for 6 month braces.
Molars, canines and incisors must be assessed as a class 1,11 or 111. In my experience the molar relationship is the most important factor when decideding how to proceed. Many good text books will show you how to do this. A class 1 molar relationship will mean that as long as the crowding can be corrected then an aligned maxillary arch will fit correctly with a well align mandibular arch with the correct amount of overjet and hopefull overbite. A class 11 dentition well aligned will result in significant increase of overjet which may or may not be acceptable. A class 111 dentition well aligned may result in a complete anterior crossbite and this is the case that you must be very careful with. A class 111 crowded case is usually best treated with an extraction of a lower incisor and class 111 holding elastics.
Next time we will look at assessing and treating crowding in the 6 month braces patient.
Dr Huw Anthony BDS hons. cert ortho
