Saturday, 28 May 2011

Pitch,Yaw and Roll

The advent of CBCT and stereo photogrammetry makes it possible to directly view  three-dimensional relationships within the  dentofacial complex . Historically, orthodontic diagnosis addressed only three of the six characteristics  required for describing the position of the  teeth in the face and the orientation of the  head. A total description of these relationships is analogous to  what is required to  describe the position of an airplane in space  (Ackerman et al. 2007). Three-dimensional movement in space is  defined by translation (forward/backward,  up/down, right/left) combined with rotation  about three perpendicular axes (pitch, roll and yaw) (F. By adding these rotational axes into  the  characterization  of  dentofacial traits, the orthodontist has greater  accuracy in description .
The value of systematically enhancing the Angle classification by including transverse and vertical characteristics in addition to anteroposterior relationships for the face and the dentition is universally accepted. Three aeronautical rotational descriptors (pitch, roll, and yaw) are used here to supplement the planar terms (anteroposterior, transverse, and vertical) in describing the orientation of the line of occlusion and the esthetic line of the dentition. Each of the latter traits affects the modern clinical practice of orthodontics because of its greater focus on dentofacial traits beyond the correction of malocclusion. This offers further refinement of diagnostic description and classification.



A complete description is exactly analogous to what is necessary to describe the position of an airplane in space. This records movement in 3D space: translation (forward/backward, up/down, right/left), which must be combined with rotation about 3 perpendicular axes (yaw, pitch, and roll). The introduction of the rotational axes into the description of dentofacial traits (and orthodontic problems) improves significantly the precision of the description and therefore facilitates development of the problem list.



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