2012 年 10 巻 4 号 p. 330-335
The purpose of this study was to determine the optimal concentration of contrast medium incorporated in a radiopaque implant template for gingival form using computed tomography (CT). Trays were prepared with vacuum acrylic shells using casts of the gingival region of porcine mandible. Barium sulfate was then mixed with silicone impression material as a radiopaque material. The concentrations of barium sulfate were 0, 5, 10, 15, 20, 25 vol%. The CT template were replaced the porcine mandibule and was fixed by immersion in a water vessel using a phantom before cone beam CT examination. Cross-sectional images evaluated at different barium sulfate concentrations were obtained from the same part. During assessment, the images were visually evaluated using the two-alternative forced-choice (2AFC) method, during which, each of 6 radiologists made an individual assessment. Statistical analysis of the results recorded by the 6 radiologists was performed. Their assessment involved allocating a score to each barium sulfate concentration image ; the 5 vol% and 10 vol% concentration images subsequently recorded the highest scores. In particular, cross-sectional images of 5 vol% barium sulfate scored higher than those of all other concentrations. CT templates comprising silicone impression materials containing 5 vol% barium sulfate were easy to use with regard to precise visualization of gingival form. The present study suggests that CT templates comprising silicone impression material containing 5 vol% barium sulfate provide useful information in the assessment of soft tissue structures such as the gingiva prior to implant treatment.
