Visualization of osseointegration of maxilla and mandible dental implants

Purpose We present a new, hybrid visualization method that can assist in assessing the degree of osseointegration of dental implants. Method The method is based on radiographic imaging, three-dimensional (3-D) volume reconstruction, and color coding of bone density. It provides both a 3-D image of the titanium implant and the implant site, and a two-dimensional (2-D) profile of the lingual and buccal sides of the implant, exposing possible weaknesses in the supporting bone structure. The visualization procedure described here consists of 2-D cross-sectional CT imaging, 3-D gradient-based hardware-accelerated volume rendering using 3-D texture mapping, implant site extraction using 3-D selection of a 2-D cross-sectional, tri-linearly interpolated 2-D image, computation of a bone density profile and line integral along the implant, and 3-D hybrid rendering of the implant site and the derived bone density information in its anatomical context. This method has been demonstrated to be successful in enabling the mapping of information derived from virtual bone density measurements onto a geometric object, thus providing the necessary information to relate other information from mechanical testing or simulations to the respective site. Results A high-resolution scan of a cadaver was used as a reference data set. The hybrid view, a combination of 2-D density profile and 3-D color-coded density rendering, turned out to be very intuitive and easy to interpret. The 2-D view was also useful for relating standard 2-D X-ray imaging with enhanced 3-D imaging of bone density. On top of this, our image-based method was used for cross-validation of a mechanical testing method. It turned out that the results from mechanical testing of osseointegration were very well correlated with the results from our image-based 2-D and 3-D methods. Conclusions Since these two methods work in completely different ways (mechanical vs. radiographic) and the results came out are the same, the results provide evidence that both methods for assessing the degree and location of osseointegration are valid. Further studies using additional scans on living subjects will be conducted to provide additional evidence. Cost-efficient X-ray imaging can be used to replace the simulated implant-aligned 2-D X-ray views that were obtained from a 3-D scan.