[Not Available]. / Les articulations de la tête et l'architecture occlusale.

Short Communication selected from the Oral Presentations of the 56th Congress of the Groupèment International pour la Recherche Scientifique en Stomatologie et Odontologie, Peñafiel (Portugal) May 2012.

[Euclid and Pythagorus in the 21st century. A proposal on various harmonious craniofacial and occlusal constants]. / Euclide et Pythagore au XXI degree siecle. Propos sur quelques constantes harmonieuses cranio-faciales et occlusales.

The aim of this work was to study the architectural relationships between different squeletal and dental pieces participating in the mastication, and to prove their fixity. We have at our disposition a collection of teleradiographies taken from profile on the same subject, over the course of several years; 3000 of them have been selected. With the help of tracings, where are drawn 36 degrees angles; or 72 degrees and 108 degrees; we systematize our locations. Together with our ten experimenters, we have noticed the existence of a parallelism between the graphic representations of the Bouvet occlusal plane, the sphenoïdal planum (sphenoïdale bone) and the course of the second trigeminal branch (trigeminus nerve) in its infra-orbital section. The angle of those different marks with the superior clivus (quadrilateral strip of the sphenoïd) (dorsum sellae) still measures 72 degrees. It is equal to 108 degrees with the graphic representation of the third antero-inferior pterygoïd process. (pterygoïdeus process). The angle between the superior clivus and the pterygoïd process still measures 36 degrees. These works are new contributions to the orthodontic, occlusodontic or prosthetic conceptions.

[The occlusal plane: an architectural myth or a proprioceptive myth?]. / Plan d'occlusion: mythe architectural ou mythe proprioceptif?

From two radiographic pictures of the head in profile, in meantime of few years, with the same person, the author proves that occlusal plane doesn't vary during growth in comparison with the pterygo-clivien compass (Stable zone leasing against pterygoïd process and superior clivus). The orientation of occlusal plane crossing by contact of the first molars and the middle of incisive intersection has an approximately analogous value. This value is equal to 110 degrees for the sample population, whatever the person's morphology and the lapsed time is. The occlusal plane moves parallel to himself and gets lower on a sagittal téléradiographic picture.

[The suborbital plane and the pterygoid-clivus trihedron: development during growth]. / Droite sous orbitaire et triedre pterygo-clivien: evolution au cours de la croissance.

We use three X ray radiographics pictures for every child at two different ages and we make the orthogonalization's step. The orientation of the "D.S.O." straight in "3" is studied with the "pterygo-clivien tripod", stable superposition's structure during growth.

[A cephalometric study of the cervical and palatal movements during growth]. / Etude télécrânienne des mouvements cervicaux et palatins au cours de la croissance.

The sagittal and anterior position of the hyoid bone is at the origin of the changes in orientation of the palatine laminae. A posterior-anterior movement of this bone allows the tongue to liberate the posterior part of the oral cavity; the palatine laminae rotate forwards and downwards. The opposite case is verified in the same way; the naso-palatine canal is a very malleable area, allowing a lowering of the anterior part of the palatine laminae. The vertical variations of the hyoid bone have little effect on the palate.

[The first permanent molars and palatal or mandibular variations]. / Premières molaires permanentes et variations palatine ou mandibulaire.

101 children, each of them with two teleradiographies, were selected. The first X-ray was taken at the time of the mixed dentition, the second one, when the permanent dentition was established. The purpose of the research is to show the oscillations of the palatine and mandibular planes, and their link to the movements of the first permanent molars. The palatine plane is found to swing between -7 degrees and +5 degrees with an average of -0.97 degree. The posterior part of that plane rocks downwards in 51% of the children. The limits are -7 degrees and -1 degree, with an average of -3.2 degrees. In 22%, the plane rocks upwards between +1 degree and +5 degrees with an average of +3.1 degrees. In 27% it moves parallel to itself. The posterior part of the mandibular plane varies between -6 degrees and +5 degrees, with an average of -1.1 degrees. It rocks downwards in 48% of the cases, between -6 degrees and -1 degree with an average of -3.9 degrees. In 22% of the children, this plane rocks upwards between +1 degree and +5 degrees with an average of +2.5 degrees. In 30%, it moves parallel to itself. The overall result is that the more the posterior part of the palate, or of the mandible moves downwards, the more the first permanent molars get straight or move forwards.

[A method of orthogonalization of X-ray negatives by image processing permitting a 3D reconstruction of the elements of the head]. / Méthode d'orthogonalisation de clichés radio X par traitement d'images autorisant la reconstruction 3D d'éléments de la tête.

In order to know better the unrolling of the growth, we dispode several radiographics elements which is sometimes difficult to connect with themselves. Using the computer, may give us the solution to this problem. We describe here a soft which authorizes the 3D reconstruction dating from X-ray radiographic pictures. During step called orthogonalization, the three pictures from the front, from profile and from under, are retalling by the soft. When it's realized, any visible point from two views will automatically be visible in the third view.

[The pterygoclival trihedron: its 3D reconstruction, stability and possible variations during growth]. / Le trièdre ptérygo-clivien: reconstruction en 3D, stabilité ou variations possibles au cours de la croissance.

The growth's study, from skull's radiographics, needs the use of superposition's structures. Three X-ray radiographics pictures from the front, from profile and from under are retalling by a soft. This orthogonalization's step has been realized for every child at two different ages. The reconstruction of the "clivus" straight and "pterygoïde" straights from three views gives the "pterygo-clivus triedre" which stability is studied for time.