A paradigm shift in the diagnosis & management of dentofacial deformities

For many years the diagnosis of dentofacial deformities and the prediction planning of the surgical correction were limited to two dimensional (2D) radiographs and photographs. There are many limitations associated with this approach which include geometrical distortion and superimposition in 2D images, evaluation and prediction planning are limited to the patients’ profile, facial asymmetries are not fully analysed and 3D soft tissue changes following orthognathic surgery are not considered. Over the last few years there has been a significant paradigm shift in our clinical approach towards the management of dentofacial deformities (Swennen et al., 2009). The ultimate goal of orthognathic surgery is to improve the harmony of soft tissue appearance which is usually the patients’ main concern. Improving labial seal, naso-labial configuration and chin prominence are amongst the main objectives for orthognathic surgery. Improving medio-lateral, vertical and antero-posterior asymmetries of facial morphology can be readily achieved with standard orthognathic procedures. The morphology of the vermillion border of both upper and lower lips is altered significantly with orthognathic surgery. Therefore, the magnitude and direction of movement of the osteotomy segmented should be planned to archive the required alterations in the oro-facial appearance. This would not be achieved unless the position and the inclination of the teeth are pre-planned to allow the desired movements of the osteotomy segments (Fig. 1). Therefore, it is a necessity for the majority of cases to undergo presurgical orthodontic treatment to decompensate and reveal the true extent of the underlying deformities in preparation for orthognathic surgery. The team approach between the orthodontist, surgeons and technologist is essential to plan the cases appropriately and archive the best possible results following orthognathic surgery (Fig. 1). Figure 1 A diagram illustrating the mechanism of planning and executing the surgical correction of dentofacial deformities. The need for comprehensive and full analysis of dento-facial morphology has inspired clinicians to adopt 3D imaging modalities to capture and analyse facial soft tissue morphology, the shape of the jaw bones as well as the dental occlusion (Benington et al., 2010, Fig. 2). Three-dimensional imaging techniques have attempted to overcome the shortcomings of conventional two-dimensional methods. These techniques have included: morphanalysis, laser scanning, 3D computerised tomography scanning, 3D ultrasonography, Moire topography and contour photography. Figure 2 A diagram illustrating the 3D images of the face, skull and dentition.