ABSTRACT BOOK

14-15 mars 2003

Chirurgie Orthognathique, Distraction et Esthétique Faciale

FONTENELLE A.
ORTHODONTICS , SURGERY : CONFLICTING OR CONVERGING OBJECTIVES AND MEASURES.

Aesthetic is the goal of both the orthodontist and the oro-facial surgeon.
While the surgeon focuses on the facial balance, the orthodontist concentrates on the occlusal objectives. Usually an ideal occlusion is the key for the best facial appearance and vice versa : the team work is simple.
But in some cases the orthodontist, in order to obtain an ideal occlusal relationship, may need surgical modifications that are detrimental to the facial harmony while in some other cases the surgeon may plane skeletal changes reaching a  good facial harmony but  achieving an unacceptable occlusion

Both surgeons an orthodontists have to work together on the treatment plans to solve conflicting objectives and this is even more important in complex cases when perio and prosthetic treatments are needed.

But the best treatment plan is useless if the patient does not accept it. The patients who consult a surgeon in order to obtain an improvement of facial aesthetics may anticipate a fast treatment with only few days of hospitalisation and are not prepared to wear braces for one year or more, while the patients who seek orthodontic treatment are anticipating a non-traumatic treatment without any major risk  and are usually not willing to accept a surgical solution to their problem.
The orthodontists have to improve the treatment procedures by using invisible appliances, while the surgeons have to reduce the aggressiveness of their procedures ;both have to be aware of the potential and limits of each other.

 
FERRI J., RAOUL G., VEREECKE F., LEMIERE E.
INTERET DU RECUL MAXILLAIRE PAR OSTEOTOMIE DE LEFORT I DANS CERTAINES CLASSES II DENTO-SQUELETTIQUES

Alors que l'ostéotomie de Lefort I est le traitement habituel des insuffisances maxillaires, elle peut, dans un certain nombre de cas, être utilisée pour traiter certaines classes II où il existe une importante promaxille.

En effet, le traitement du décalage antéropostérieur de ces dysmorphoses, par la seule ostéotomie mandibulaire, peut donner un aspect disgracieux malgré une occlusion satisfaisante.  L'ostéotomie de Lefot I de recul, seule ou associée à une ostéotomie sagittale d'avancée, est alors le traitement de choix.

Les indications, la technique chirurgicale et quelques résultats seront présentés.

 
OLSZEWSKI R., REYCHLER H.
ACRO 4D : NEW 4D CEPHALOMETRIC ANALYSIS FOR FOUR DIMENSIONAL DIAGNOSIS, 3D PLANNING AND SIMULATION IN ORTHOGNATHIC SURGERY

This new analysis permits to study different cranio-maxillo-facial malformations and facial asymmetry. The visualization of ACRO 4D analysis is done in 3D, understanding the results must be done in 4D (3D and time), which associates the Moss neural matrix theory, the Delaire ideal individual equilibrium concept and the new concept of structural–functional guidance. The ACRO 4D analysis contains 38 reference points and 28 plans. 5 angles, 10 surfaces and 9 volumes can be measured. The ACRO 4D analysis has been decomposed in 16 modules and 6 standard planning procedures have been implemented by combining these modules. 10 of these modules represent the 2D to 3D transformation from 2D Delaire analysis. The last 6 modules study the symmetry-asymmetry of the different craniofacial regions. The ACRO 4D analysis guides the surgeon, step by step, to the diagnosis, with clear guidelines and 3D incorporated examples. The generic tools, developed in this software, can achieve the transformation of every 2D to 3D cephalometric analysis with the creation of the independent reference points, lines, plans and volumes. Our further investigations are the validation of the method accuracy, the clinical validation on patients and development of 3D simulation based on this ACRO 4D analysis.

 
CHARRIER J.B., DELATTRE J ., DENOYELLE F., GARABEDIAN E. N.
DERMOÏDES CRANIOFACIAUX : THEORIE EMBRYOLOGIQUE UNISSANT LES KYSTES ET FISTULES DU DOS DU NEZ

OBJECTIVE: Nasal dermoid sinus cyst (NDSC) is an uncommon congenital lesion presenting as a large panel of midline craniofacial anomalies. The objective of this study was to review and reanalyze embryological hypotheses concerning NDSCs, and to propose an embryological theory unifying the various anatomical characteristics of these lesions.
RESULTS: We report the first case of intradiploetic frontal extension of a NDSC in a 9-month-old boy presenting as a medial frontal fistula with recurrent frontal swelling six month after a mild frontal trauma. Complete surgical removal was performed. There was no evidence of either persistent or recurrent disease one year after surgery.
CONCLUSION: The embryological and anatomical origins of NDSCs are reviewed. We propose to distinguish anterior topography of NDSCs, located at the anterior skull base level from the basal one, located at the middle skull base level. We reexamine and rehabilitate a forgotten embryological theory, which unify the various clinical presentations of anterior NDSCs.

 
BOULETREAU P., BRETON P., FREIDEL M., LONGAKER M.T.
INSIGHT INTO THE MOLECULAR MECHANISMS GOVERNING DISTRACTION OSTEOGENESIS

Although the histologic and ultrastructural changes associated with distraction osteogenesis have been extensively delineated, relatively little is known about the molecular mechanisms governing this process. However, such information has significant clinical implications because it may enable targeted therapeutic manipulations designed to accelerate osseous regeneration. Recently, our laboratory has described a rat mandibular distraction model that provides an excellent environment for deciphering the molecular mechanisms that mediate successful and unsuccessful distraction osteogenesis.
Using this model, we have demonstrated that gradual distraction osteogenesis stimulates the production of osteoinductive growth factors (Transforming Growth Factor-alfa 1) and extracellular matrix molecules (Collagen I and Osteocalcin). Furthermore, we have begun to investigate the molecular mechanisms by which successful gradual distraction osteogenesis differs from acute lengthening. We have demonstrated that gradual mandibular distraction, in contrast to acute lengthening, results in net accumulation of bone specific extracellular matrix products.
Based on experimental works, we present the hypotheses and current research that have furthered our knowledge of the molecular mechanisms that govern distraction osteogenesis. We believe that novel systems like the rat model will facilitate our understanding of the biomolecular mechanisms that mediate membranous distraction osteogenesis and will ultimately guide the development of targeted-strategies designed to accelerate bone healing.

This work was partially supported by the Leibinger-Stricker grant 1999