[Evaluation of the mid-term results of trident osteotomy using orthodontic goniometry]

The authors study a series of twenty patients who underwent a "trident" maxillary osteotomy for transversal deficiency. They try to have a good evaluation of the exact value of the inter-molar distance after one year, in comparison with the expected value on the plaster casts before operation. Furthermore, they measure the axial modifications of the first molar, which consists in vestibulo or linguo version. For this study, they use a simple method which is called "orthodontic goniometry" and give a great precision. The transversal augmentation seems to be quite stable, with only fifteen per cent lost in the measured intermolar distance. But there are dental axial changes in eighty per cent of the patients. The most common modification consist in vestibular inclination, without damage for the result. But in thirty per cent of the cases, a palatal inclination is observed, with deterioration of the results. This is a good reason for maintaining a palatal contention during at least six months after surgery.