[Evaluation of the mid-term results of trident osteotomy using orthodontic goniometry]. / Appréciation du résultat à moyen terme de l'ostéotomie en trident par la goniométrie orthodontique.

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.

[Modifications to the skin profile following facial osteotomy]. / Modifications du profil cutané consécutives aux ostéotomies faciales.

Soft tissue changes resulting of maxillary and/or mandibular osteotomies need to be evaluated with a great accuracy for a better prediction of the post-operative profile. As the aesthetic result seems to be most important for our patients, it is necessary to study the relations between the displacements of characteristic cutaneous points and hard structures below, osseous or dental. Then, a retrospective statistical computerized study was performed on 45 patients who underwent facial osteotomies at least three months before. The vertical and horizontal positions of 14 osseous or dental landmarks and 16 cutaneous points were recorded. Corresponding displacements were calculated for each of these, but only six cutaneous and 9 osseous displacements were selectionned for this study. A first correlation research was made, with determination of the lineary regression equations, when it was possible. Then a multivariate study was performed for each cutaneous point, with determination of multiple regression equations. Comparison between the two methods of prediction shows a S.D. over 2 mm for the simple regression versus a S.D. of about 1 mm for the multiple regression. On the other hand, it seems that it is possible to predict the horizontal displacements with the first method without important error. But the vertical displacements cannot be evaluated with good prediction, and particulary the stomion movements. It will be necessary to consider other parameters to obtain better correlation coefficient. But it is obvious that one can join together different groups of patients for a soft tissue changes study with the same results than after separation of those. In fact, the soft tissue reactions are the same although the surgical procedures are different.