H. HUSSTEDT 1, M. WICHMANN 2 (1 Abt. Neuroradiologie, 2 Abt. Zahnärztl. Prothetik, Medizinische Hochschule Hannover, Germany)
Sufficient knowledge of the precise position of the pulp as it relates to the exterior tooth contour is absolutely essential for cavity and crown preparation. It minimizes the probability of pulp exposure and helps the dentist in preserving the vitality of the pulp, one of the most important aspects of dental treatment. In the past, cross-sections or radiographs of extracted teeth have been used to demonstrate the relationship between the pulp and the coronal outlines of the teeth. These techniques were restricted by the limited expressiveness of two-dimensional images. Producing transparent replica also allowed only limited studies of pulp anatomy because of optical distortion effects. A general disadvantage of all techniques described so far was the necessity of eroding dental hard tissue and therefore de- stroying the teeth. The purpose of the present study is to present a nondestructive method using high resolution computed tomography for three-dimensional reconstruction of tooth structures. Spiral computed tomography was performed with a GE HiSpeed Advantage RP device (General Electric Medical Systems) using 1mm sections for highest possible resolution. The radiographic exposures were taken with 140 kV, 160 mA, 10 cm Field of View and overlapping three-dimensional reconstruction using high- resolution algorithms. Subsequent processing with a workstation (Sun Sparc 10) under Advantage Windows resulted in detailed images revealing the anatomy of the pulpal chamber in relation to the outer tooth contour. Digital processing allowed to change virtual viewpoints resulting in extraordinary views of the internal structure of human teeth.