STERILIZATION & CROSS INFECTION IN DENTISTRY;

Abstract

Introduction: Conventional ultrasound technology can provide only two-dimensional sectional views of the fetal face. In fetuses with an unfavourable position individual sectional planes of the face cannot be demonstrated with 2D ultrasound and fetuses with complex face anomalies require an evaluation in multiple planes. Despite the fact that an experienced examiner can readily piece together two-dimensional planes to create a three-dimensional mental image of the fetal face, the parents cannot be expected to form an accurate three-dimensional picture in their minds. Material and Methods: High quality 3D/4D imaging of the fetal face requires an ultrasound equipment with a transvaginal and transabdominal 3D/4D transducer. Once the fetal profile is demonstrated with 2D ultrasound, volume acquisition is activated and a volume of the fetal face is stored in the memory of the ultrasound system. Results: 3D ultrasonography is a reliable tool in the demonstration of normal and abnormal fetal anatomy. The simultaneous display of all three orthogonal planes allows a precise control of every fetal plane such as the facial profile, even in severe oligohydramnios. When one plane is rotated or shifted, corresponding changes are displayed at once in the two other planes. This provides an ideal basis for a further detailed survey. The translucency mode provides a complete survey view of the fetal skull, similar to the appearance of an X-ray film. The three-dimensional surface view of the fetal head allows a precise depiction of surface anomalies such as facial dysplasia, cleft lip/palate and cyclops. HDlive technology offers even more photo-realistic images of the region of interest due to a moveable virtual light source with different shadowing effects and an advanced skin rendering technique. The alternate use of the different rendering modes enables the examiner to visualize the region of interest in that mode that is best for the demonstration or exclusion of a fetal defect. Rendering of an animation sequence gives an excellent view to the fetal face from different angles. With 4D ultrasound the movements of the fetus can be visualized three-dimensionally in real time. Summary: Compared with conventional 2D ultrasound, 3D/4D ultrasonography provides the operator with much more visual possibilities to identify facial abnormalities of the fetus.