ABSTRACT
OBJECTIVES: The diagnostic advantages of digital volume tomography (DVT) over conventional imaging and computed tomography are demonstrated in terms of the respective radiation exposure. The potential role for three-dimensional imaging in cleft lip and palate patients is illustrated on the basis of clinical examples. METHODS: The radiation exposure resulting from scans using a cone beam DVT (NEW TOM QR-DVT 9000, Marburg, Germany) was measured with an Alderson-Rando-Phantom (The Phantom Laboratory, New York, NY) and compared with that resulting from other standard imaging modalities. The patient sample consisted of young children with cleft lip and palate on whom orthodontic and surgical treatment was planned on an interdisciplinary basis at the University-Hospital of Heidelberg. RESULTS: Digital volume tomography allows high-quality three-dimensional imaging of the premaxilla region, with an effective equivalent investigation dose of (110 kV, 5.4 mA) 0.342 mSv based on ICRP recommendations. While the effective equivalent investigation dose for DVT is higher than that for standard imaging techniques (for example digital panoramic radiograph Orthophos Plus DS Ceph (66 kV, 8 mA) 0.016 mSv), it is much lower than that for a normal CT scan (e.g. Picker International Inc., Highland Heights, OH) adjusted at (spiral 130 kV, 125 mA, and 30 mA, 1.5 s) 2.27 mSv. Digital volume tomography provides extensive data important in clinical decision making. CONCLUSIONS: The clinical examples show the good applicability of DVT with a reduced radiation dose.
Subject(s)
Cleft Lip/diagnostic imaging , Cleft Palate/diagnostic imaging , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Radiographic Image Enhancement/methods , Tomography, X-Ray Computed/methods , Child, Preschool , Cleft Lip/surgery , Cleft Palate/surgery , Female , Humans , Infant , Palate/diagnostic imaging , Patient Care Planning , Phantoms, Imaging , Radiation Dosage , Radiography, Panoramic , Tooth, Deciduous/diagnostic imaging , Tooth, Supernumerary/diagnostic imaging , Tooth, Unerupted/diagnostic imagingABSTRACT
OBJECTIVES: To determine the geometric accuracy of digital volume tomograms to assess their usability for implant planning. METHODS: A measuring object with 216 measuring points, whose geometry is exactly known, is X-rayed with a NewTom 9000 cone beam scanner; thereafter the geometry of the volume tomogram of the object is compared with the original body. RESULTS: Considering all three coordinate axes, geometric mean deviations of 0.13 +/- 0.09 mm with a maximum deviation of 0.3 mm were determined. These geometric deviations are below the resolution power of the volume tomograph. CONCLUSION: The digital volume tomographies of NewTom 9000 present images which are geometrically correct and, from a geometrical point of view, suitable for three-dimensional implant planning.
Subject(s)
Radiography, Dental, Digital/methods , Tomography Scanners, X-Ray Computed/standards , Tomography, Spiral Computed/instrumentation , Dental Implantation, Endosseous , Patient Care Planning , Phantoms, Imaging , Reproducibility of ResultsABSTRACT
BACKGROUND: Trauma to the inferior alveolaris nerve is one of the worst complications of the surgical removal of wisdom teeth. With digital volume tomography (DVT), a new imaging technique has been introduced to dentistry and oral and maxillofacial surgery, offering the same options for reconstruction as computer tomography (CT). Since mid-2000 we have been performing imaging via DVT in the case of deeply dislocated third molars sited very close to the nerve canal. METHODS AND RESULTS: In the present study DVT images were made for a total of 81 lower and 11 upper wisdom teeth; the existing orthopantomogram of these teeth had not been sufficiently clear to allow a diagnosis in these cases. Detailed visualization of the wisdom tooth concerned in all planes was possible in each case, and exact reconstruction of the course of the inferior alveolar nerve was successful in 93%. DISCUSSION: In summary, DVT is an advantageous and practical imaging technique that can be used for to extend the diagnosis in surgery on third molars.
