Abstract
Three-dimensional image reconstruction and analysis of teeth from serial sections have been tried in oral anatomy and orthodontics. In oral and maxillofacial surgery too, three-dimensional information about natural teeth is needed as basic data, when dental implant insertion and/or mandibular reconstruction. In this study, three-dimensional images were obtained to observe and analyze the surface area and volume of the natural teeth.
Fourteen extracted adult teeth were used in this study which included incisors, canines, premolars,and molars of the upper and lower jaws.
Teeth were first embedded in polyester resin with noncalcification, and 200 microns thick serial sections were made. After enlargement, each section was traced in terms of the enamel, dentine, and pulp cavity contours and the information was fed into a computer. Three-dimensional data of each tooth were then obtained by using three-dimensional image reconstruction software (TRI).
In the surface area of the root of natural teeth, maxillar incisor and canine were larger than their mandibular counterparts; molars were larger in the mandible than in the maxilla. Results were the same in terms of the dental volume. When the root surface area of natural teeth was compared with that of Branemark implants (3.75 mm in diameter), lateral incisor, premolar in the maxilla and incisor, lateral incisor, canine and first premolar in the mandible turned out to be equal to a 13～18 mm fixture. The surface area of canine, first molar in the maxilla, and molars in the mandible were larger than the surface area of a 20 mm fixture.
This method is time-consuming but far more accurate than the usual method; it is also very effective. In the future, we shall try to obtain average values of the surface area and volume of natural teeth for more detailed analysis, e.g., dynamic analysis when a tooth is under occlusal stress, and for comparison with dental implants.
