[Cranial Facial 3D Biometry: Statistical analysis of Class II disharmonies]. / Biométrie cranio-faciale 3D: analyse statistique des dysmorphies de classe II.

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.

[Cranio-Facial 3D Biometry: Complete analysis of a case of class II "limit surgery"]. / Biométrie cranio-faciale 3D: analyse complète d'un cas de classe II « limite chirurgicale ¼.

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.

[Influence of trigeminal nerve lesion on facial growth: study of two cases of Goldenhar syndrome]. / Influence de l'atteinte trigéminale sur la croissance faciale : étude de deux cas de syndrome de Goldenhar.

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.

[Sexual dimorphism and facial cavities: a 3D imaging volumetric study]. / Dimorphisme sexuel et cavités faciales: étude volumétrique en imagerie 3D.

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.

[Study of asymmetries in the severe antero-posterior disharmonies]. / Etude des asymétries dans les grandes dysmorphies antéro-postérieures.

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 cephalometry: applications in clinical practice and research]. / Céphalométrie tridimensionnelle: applications en clinique et en recherche.

A 3D cephalometric analysis method from scanner acquisition has been developed thanks to a long collaboration between Dr Treil and the Department of Orthodontics in Toulouse III University. It allows a perfect knowledge of maxillo-facial architecture using fourteen landmarks related to the neuromatricial axis of facial growth. These landmarks can be identified without ambiguity. The marking of each tooth relative to dental arches (gravity centre coordinates and torque and tipping of each tooth), and the location of arches relative to maxillo-facial frame are given by the analysis. Description and reconstruction of dental and maxillo-facial anatomy are possible with three levels: maxillo-facial frame, maxillar and mandibular bases and dentoalveolar level. The method not only gives more precise information than conventional cephalometrics in anteroposterior and vertical directions, but it allows transversal analysis and asymmetry measurement. Applications are numerous in research as well as in clinical medicine: analyses of cases border line surgery, surgical set-up, facial asymmetry, analysis of dentoalveolar compensations, definition of therapeutic aims, occlusal analysis and set-up, study of evolution in anthropology-primatology, study of growth etc. This method of description using a pattern of landmarks is perfectly adapted to the last developments of modern research techniques: morphometric geometry with Procustes superimpositions, EDMA, TPS, FEM.

Estimation of pediatric skeletal age using geometric morphometrics and three-dimensional cranial size changes.

This paper presents a method for estimating the skeletal age of children based on the centroid size of their face and their basicranium, derived from the three-dimensional coordinates of anatomical landmarks. The sample consists of computed tomography scans of 127 children (54 boys, 73 girls) of mixed origin living in the area of Toulouse (France), ranging in age from a few days to 18 years. The purpose of the present investigation was, first, to increase the variety of age-related structures theoretically available for pediatric skeletal age estimation and, second, to devise a method that can be applicable from early postnatal age to the end of adolescence with a satisfactory accuracy independent of age and even a better accuracy with greater age. We examined the relationship between the chronological age and the centroid size, calculated by using geometric morphometric methods and a linear model. With the aid of cross-validations, the statistical analysis indicates that the centroid size of the facial skeleton can be used an age-related variable without any loss of accuracy with increased age, contrary to most of the methods of pediatric age estimation. The standard error was always lower or equal to 2.1 years (at the 95% confidence level) and decreased in our sub-sample of older children represented by a larger number of individuals.

[Three-dimensional imaging and cephalometry of cranio-facial asymmetry]. / Imagerie et céphalométrie tridimensionnelles des asymétries cranio-faciales.

The 75th meeting of the French Orthodontics Society will be held in Biarritz May 8-9-10-11 2002. The main topic for discussion will be: "facial asymmetry". During the meeting, authors will present study of facial asymmetries using a new innovative three-dimensional cephalometry. The method combines CT scans data, anatomical landmarks and mathematical tools to create, using the "Cepha" software, a 3D model of the human face. Balance and symmetry of the model are stable enough to define normality for each individual even with different ethnic and cultural origins. Unbalance and asymmetry characterize pathologies. Follow up shape and size of models allows growth prediction and modeling. The model is in the process of becoming the indispensable reference for all those who are interested in studying the human face: Orthodontics, Surgery, Anatomy, Anthropology, Plastic surgery, Forensic Medicine.

[Orthodontic approach to asymmetry]. / Approche orthodontique des asymétries.

From an orthodontic point of view, asymmetries can be gathered in three great clinical entities: mandibular lateral deviations, dental asymmetries without skeletal involvement, skeletal asymmetries. Once the therapeutic aims and the principles of the orthodontic approach of these dysmorphoses have been recalled, the authors present the various orthodontic means implemented in this type of treatment. Four cases treated illustrate those types of treatment. Vertical non-surgical asymmetry may have an obvious local origin, for instance, a unilateral damage to a nerve. but usually, there is no evident origin. Frequently the occlusal slippage of a severe sagittal or a vertical malformation, which may evolve as a borderline surgery case, is suspected to be the real cause. In these cases, the diagnosis is always late, with the ending growth. The treatment needs peculiar strong asymmetric mechanics and, sometimes, unilateral mixed extractions. The post-treatment occlusion can be unstable; for this reason, the finishing steps must be carefully conducted. Four clinical case reports develop these points ov view. Multidisciplinary treatments prove very useful to solve three types of clinical situations. In the adult patient, facial esthetics are indicated in severe dentofacial asymmetries. Esthetic improvements of dental nature are still required in deviated smiles, or frontal tippings of the occlusal plane. In addition, asymmetrical intermaxillary relationships will lead to functional anomalies: TMJ disorders, dental wear or lingual dysfunctions. Finally, multidisciplinary treatments in the adult concern the occlusal transverse anomalies, the lateral crossbites, the Class II subdivisions, the deviations of the inter-incisor midlines or unilateral edentulousness. The various plans of treatment, as well as the orthodontic mechanics used, are illustrated in the following development by clinical cases.

[3-dimensional cephalometry in orthodontics. The current possibilities of Cepha 3DT software]. / Céphalométrie tridimensionnelle en orthopédie dento-faciale. Les possibilités actuelles du logiciel Cépha 3DT.

A 3D cephalometric analysis method from a scanner acquisition, has been developed thanks to a long collaboration between the CIRAD modeling Laboratory and Jacques Treil. The model of skeletal description is based on eight landmarks related to the neuromatrical axis of facial growth (heads of the mallei, supraorbital, suborbital, submental points); it has been abundantly described. The purpose of this work consists in presenting the dentoalveolar level of the analysis. The description and the marking of the arches and the teeth mainly rest on the systematic use of a mathematical tool, the calculation of the central matrix of inertia, and on three fundamental choices: the identification of the dental arches from their constituting teeth leaving aside any alveolar marking, the marking of each tooth relative to the arch, as it can be observed by the orthodontist's eye, and not relative to the craniofacial architecture, the definition of the position of each tooth by the orientation of its coronoradicular axis and not its sole buccal side, Their uses in orthodontics are numerous: diagnosis, choice of the mechanics, therapeutic simulation, therapeutic follow up, analysis of the findings... Clinical applications illustrate the theoretical presentation.