OBJECTIVE:This study aims to evaluate the efficiency and accuracy of an automated three-dimensional (3D) cephalometric software in diagnosing dento-skeletal dysmorphoses and its concordance with standard clinical diagnosis used in orthognathic surgery. METHODS:A retrospective study was conducted at the Department of Otorhinolaryngology and Maxillofacial Surgery of the University Hospital of Nice. Fourteen patients who underwent bimaxillary surgery were included in this analysis. Standardized cephalometric and clinical diagnoses were compared with automated software-generated diagnoses. The statistical agreement between the two approaches was analyzed to assess the reliability of the software. RESULTS:The software demonstrated a great agreement with our standardized diagnosis and a high reproducibility rate for skeletal measurements. However, it displayed discrepancies in specific parameters, particularly in soft tissue assessments (lack of measurements) and occlusal characteristics. CONCLUSION:Automated 3D cephalometry has significant potential as a diagnostic tool in orthognathic surgery. However, refinements are required to improve its accuracy, particularly in soft tissue assessment and occlusal analyses, before it can be fully integrated into routine clinical practice.

With the conventional 2D exam of clinical cases, the diagnosis is penalized by the lack of data, not only for vertical or transverse or asymmetrical problems, but for classical cases of anteroposterior dysharmonies. In these cases, the effectively used parameter, ANB angle, seems insufficient. So the authors elaborated a 3D biometry tool. The program of morphological analysis is able to deliver a complete description of dysharmony, supported by Cone Beam data capture. In the first part of this article the authors present the foundation of the model: anatomical reference, skeletal landmarks, teeth location by inertia matrix calculus, parameters, diagnosis and aid to treatment plan. The second part is the presentation, step by step, of the program in function, analyzing a great case of Class II hyperdivergent, border line surgery. All along the diagnosis way, the authors make the assistant discover all the documents given by the computer about complete 3D diagnosis and aid to treatment plan.

We could study Cone Beam documents of patients consulting in ORL with standard Angle Class I occlusion (45 ND), patients consulting in orthodontics with an orthodontic Class II (51 APNS) and patients with a surgical Class II (83 APS). The used 3D biometry calculates systematically a 164 set of parameters able to take into account all kinds of disharmonies; among which 38 parameters are specifically devoted to anterior-posterior "off asymmetry" pathologies. Then the specific Artificial Intelligence (AI) programs treat morphological data and give textual diagnoses. Analysis of the global sample aims to control the efficiency, separating different sub-samples one each other: t test appreciates efficiency of each parameter to recognize clinical sub-sample. The correlation coefficient, r, between each parameter and pseudo Angle molars Class II (GMMy-Gmmy) give the importance of its tie with Class II pathology. Presentation of parameters medium values in each sub-group gives the medium profiles. By direct comparison of patient's parameters values with medium profile, it is possible to locate patient's pathology. So we can take in account new parameters like arches upper/lower gap, anterior bases upper/lower gap, compensatingparameters... It is then possible to make more secure the clinical decision.

L'orthodontiste d'aujourd'hui est de plus en plus entraîné dans un univers tridimensionnel avec, au niveau de ses documents standards, l'apparition sans cesse plus fréquente des examens cone beam, main- tenant complétés par les empreintes numériques et les portraits 3D.

Orthodontists today work more and more in a three-dimensional (3D) universe with cone-beam examinations occurring more frequently, now supplemented by digital prints and 3D portraits.

INTRODUCTION:This cases report confirms the hypothesis that embryonic and maxillofacial growth are influenced by the peripheral nervous system, including the trigeminal nerve (V). So, it's interesting to use the stigma of the trigeminal nerve as landmarks to analyze the maxillofacial volume and understand its growth. The aim of this study is to evaluate the validity of the three-dimensional cephalometric analysis of Treil based on trigeminal landmarks.CASE PRESENTATION:The first case is a caucasian female child with Goldenhar syndrome. The second case is a caucasian male adult affected by the same syndrome. In both cases, brain MRI showed an unilateral trigeminal nerve lesion, ipsilateral to the facial dysmorphia.CONCLUSION:The results of this radiological study tend to prove the primary role of the trigeminal nerve in craniofacial growth. These cases demonstrate the validity of the theory of Moss. They are one of anatomo-functional justifications of the three-dimensional cephalometric biometry of Treil based on trigeminal nerve landmarks.

Introduction : Le présent rapport de cas confirme l’hypothèse selon laquelle l’embryogenèse et la croissance maxillo-faciale sont sous l’influence du système nerveux périphérique et notamment du nerf trijumeau (V). Il devient intéressant d’utiliser les stigmates du nerf trijumeau comme référentiel pour analyser tridimensionnellement le volume maxillo-facial et comprendre sa croissance. L’objectif est d’évaluer la validité de l’analyse céphalométrique tridimensionnelle d’essence trigéminale de Treil. Présentation des cas : Le premier cas est un enfant caucasien de sexe féminin atteint du syndrome de Goldenhar. Le deuxième cas est un adulte caucasien de sexe masculin atteint du même syndrome. Dans les deux cas, l’IRM cérébrale montre une atteinte trigéminale unilatérale, homolatérale à l’atteinte faciale. Conclusion : Les résultats de l’étude radiologique de ces cas de syndrome de Goldenhar tendent à prouver le rôle matriciel du nerf trijumeau dans la croissance cranio-faciale. Ces cas mettent en évidence la validité de la conception de la croissance neuro-matricielle de Moss. Ils sont une des justifications anatomo-fonctionnelles de la biométrie tridimensionnelle de Treil d’essence trigéminale.

La description d’une forme anatomique par un diagramme de points permet l’emploi de tous les outils de la morphométrie géométrique. Utilisant 14 points trigéminaux pour la morphologie maxillo-faciale, 10 points pour la morphologie basi-crânienne et 6 points pour l’étage orbitaire, nous avons pu identifier les formes maxillo-faciales spécifiques associées aux grandes dysmorphies (classe II ou classe III « limite chirurgicale ») ou aux simples malocclusions et rechercher des liens éventuels entre les morphologies basi-crâniennes et les morphologies maxillo-faciales.

Describing an anatomical shape with a landmark points diagram allows the practitioner to use all the tools of geometric morphometry. Using a 14 point trigeminal for maxillofacial morphology, 10 points for basicranial morphology and 6 points for the orbital area, we have been able to identify the specific maxillofacial shapes associated with the major dysplasias (Class II or Class III ‘‘surgical limit’’) or simple malocclusions and to research the possible relationships between basicranial morphologies and maxillofacial morphologies. The asymmetries have thus been linked to other pathologies. We have compared these results with those obtained by using a threedimensional cephalometric analysis and with results obtained from the literature. The conclusions on the epidemiology of the asymmetries are in agreement. Basically, the mandible with dominance of the right hemi-face was confirmed as the causative factor. The stability of the basicranial shape makes a solid case that it is not responsible for maxillofacial or occlusal pathologies.

OBJECTIVES:The various types of cone beam CT (CBCT) differ in several technical characteristics, notably their spatial resolution, which is defined by the acquisition voxel size. However, data are still lacking on the effects of voxel size on the metric accuracy of three-dimensional (3D) reconstructions. This study was designed to assess the effect of isotropic voxel size on the 3D reconstruction accuracy and reproducibility of CBCT data.METHODS:The study sample comprised 70 teeth (from the Institut d'Anatomie Normale, Strasbourg, France). The teeth were scanned with a KODAK 9500 3D® CBCT (Carestream Health, Inc., Marne-la-Vallée, France), which has two voxel sizes: 200 µm (CBCT 200 µm group) and 300 µm (CBCT 300 µm group). These teeth had also been scanned with the KODAK 9000 3D® CBCT (Carestream Health, Inc.) (CBCT 76 µm group) and the SCANCO Medical micro-CT XtremeCT (SCANCO Medical, Brüttisellen, Switzerland) (micro-CT 41 µm group) considered as references. After semi-automatic segmentation with AMIRA® software (Visualization Sciences Group, Burlington, MA), tooth volumetric measurements were obtained.RESULTS:The Bland-Altman method showed no difference in tooth volumes despite a slight underestimation for the CBCT 200 µm and 300 µm groups compared with the two reference groups. The underestimation was statistically significant for the volumetric measurements of the CBCT 300 µm group relative to the two reference groups (Passing-Bablok method).CONCLUSIONS:CBCT is not only a tool that helps in diagnosis and detection but it has the complementary advantage of being a measuring instrument, the accuracy of which appears connected to the size of the voxels. Future applications of such measurements with CBCT are discussed.

Actuellement, l'analyse de la forme 3D des structures anatomiques se fonde sur l'etude des distances ou des angles entre des points de repere (par exemple, les mesures craniometriques) ou de parametres metriques caracterisant la deformation entre des configurations de points de repere releves sur plusieurs echantillons (voir la methode de morphometrie geometrique ). Or, souvent, les differences significatives (c'est-a-dire qui ne dependent pas que de la variabilite interindividuelle normale) entre des structures anatomiques ne sont pas metriques mais structurelles . Par exemple, dans le cas d'une face prognathe, c'est tout un sous-ensemble de points de repere qui passe devant un autre, de maniere groupee et correlee. Or, ceci n'est pas toujours bien mis en evidence par les variations des coordonnees des points de reperes. Ceci suggere d'introduire de nouveaux outils de morphometrie 3D adaptes a cette approche. Nous proposons de modeliser les configurations de points de repere 3D par la theorie des matroides orientes, une structure mathematique combinatoire developpee depuis une trentaine d'annees dans le cadre de recherches theoriques en algebre lineaire et en theorie des graphes. Les matroides orientes permettent de modeliser les positions relatives de points dans l'espace sans tenir compte de leurs distances. Il est alors possible de caracteriser directement certaines proprietes geometriques comme la convexite ou l'alignement d'un sous-ensemble de points de reperes et de detecter des changements structurels comme le passage d'un point de repere a travers le plan forme par 3 autres. Nous avons commence a appliquer cette nouvelle methode a des donnees 3D de crâne pour des applications en chirurgie maxillo-faciale (en particulier, pour caracteriser les classes dentaires) ou en paleoanthropologie. Nous presenterons des resultats preliminaires sur la classification automatique de formes 3D complexes et sur la caracterisation des sous-structures les plus significatives.

Introduction : L’objectif de ce travail est d’etudier le dimorphisme sexuel au niveau des volumes des cavites faciales dans une population adulte jeune. Methodes : L’echantillon selectionne comporte 60 sujets, âges entre 18 et 30 ans, ayant beneficie d’un examen scanner de la tete. Ils sont divises en deux groupes identiques selon le sexe. Les cavites orbitaires, ethmoido-nasale et buccale sont delimitees par des points sur les acquisitions scanner 3D et leurs volumes mesures a l’aide du logiciel AMIRA® , alors que les deux sinus maxillaires sont segmentes et leurs volumes calcules. Le test Kolmogorov-Smirnov est utilise pour demontrer la normalite des variables, suivi du test « t » de Student pour la comparaison des moyennes (p ). Resultats : Les moyennes des volumes des cavites orbitaires, ethmoido-nasales, buccales et des sinus maxillaires sont plus grandes chez les hommes, alors que le dimorphisme sexuel n’a pas ete mis en evidence au niveau du rapport des volumes de chacune des cavites sur le volume facial total. Conclusion : Les volumes absolus des cavites faciales etudiees sont plus grands chez les hommes, mais pas les volumes relatifs, ce qui pourrait s’expliquer par l’existence d’une difference cranio-faciale de taille, et non de forme, entre les hommes et les femmes.

INTRODUCTION:The aim of this study was to investigate the sexual dimorphism in facial cavity's volumes of untreated young adults.METHODS:Sixty subjects, ages between 18 to 30 years, were selected and divided in two groups according to the gender. Volumes of orbital, nasal, sinusal and buccal cavities were measured from CT scans with AMIRA(®)software. The statistical studies were performed using Kolmogorov-Smirnov test for normality followed by Student "t" test (p < 0.05).RESULTS:The gender comparison reflected statistically significant differences between the volumes of orbital, nasal, sinusal and buccal cavities, volumes being larger in males. Sexual dimorphism did not appear in the ratio of each cavity volume on the total facial volume.CONCLUSION:Absolute volume of facial cavities are larger in males, but no sexual dimorphism is detected comparing volume ratios. A difference in size, but not in shape, between genders might exist.

Using the Treil 14 points cephalometric model orthodontists can prepare a complete cranio-facial anatomic assessment at three analytic levels: the framework or envelope, the basal bone and the alveolo-dental arcade. The assessment of border-line surgical antero-posterior dysmorphosis can elucidate interesting depictions of asymmetries, their relation to other malformities, and their genesis. Asymmetry arises from over-growth of one side of the face in all three dimensions of space even if, clinically, it often appears that one dimension is predominately affected. The ortho-morphic cases of Angle Class I present a little right excess or "natural" asymmetry. The Class III cases present a severe excess on the right side, while the Class II cases present an excess on the left side comparing with reference sample.

Three-dimensional imaging of teeth will increase its impact in clinical practice if reconstructions are metrically accurate. We hypothesized that, with cone beam computed tomography (CBCT) data, three-dimensional images of teeth can be reconstructed with the same accuracy and precision as with in vitro micro-computed tomography (micro-CT) data acquisition, the current reference standard. We used a sample of CBCT and micro-CT data taken of tooth germs. Volumes obtained with CBCT and micro-CT devices were statistically similar (n = 120, Passing-Bablok regression). Geometric deviations between CBCT and micro-CT three-dimensional surface reconstructions did not show any areas of important and systematic errors. Future investigations with the use of larger samples may also demonstrate that CBCT data will be helpful for a more in-depth study of other aspects of dental morphology—for example, assessing tooth development. With sufficient accuracy for clinical situations, potential future medical applications of such measurements with CBCT are envisaged.

Le modèle céphalométrique à 14 points permet une description complète de l’anatomie cranio-faciale avec trois niveaux d’analyse : la charpente ou l’enveloppe, les bases osseuses, les arcades alvéolo-dentaires. L’étude de cas de dysmorphies antéro-postérieures « limite chirurgicale » permet d’intéressantes observations sur les asymétries, leurs descriptions, leurs liens avec les autres pathologies, leurs genèses. L’asymétrie apparaît comme un excès global d’une hémi-face, affectant les trois sens de l’espace, même s’il y a souvent cliniquement prédominance de l’un d’entre eux. Les cas ortho-morphiques de classe I d’Angle sont affectés d’une petite asymétrie « normale » par excès droit. Dans les grandes pathologies de classe III, l’excès droit s’accentue alors qu’il s’estompe dans les grandes pathologies de classe II.

Imaging has always been a part of dental implant procedures from its beginning. Initially, imaging was performed by dentists. The introduction of CT scan at the end of the seventies was revolutionary. Radiologists then played a major role in image generation and distribution. For the last two years, a revolution is occurring with the availability of "cone beam" CT machines in dental offices with implant planning software. The dentist can sometimes administer the entire delivery of care: choice of imaging technique, generation and distribution of imaging data, implant planning and treatment. The radiologist's role is now only conceivable as a specialist in dental imaging, attuned to the evolution of dental implant techniques.