Radiographic alveolar bone change as an outcome measure for therapies that inhibit bone loss or foster bone gain.

Periodontal clinical trials rely on signs of gingival inflammation, periodontal probing methods, and intra-oral radiographic methods to measure outcomes of therapies that inhibit bone loss or foster bone gain. A single radiograph can provide information on the accumulation of past disease, and sequential radiographs can determine regeneration or progression of periodontal destruction. However, the precision achieved with a radiograph is associated with the actual exposure of the film and the subsequent analysis. A film exposed using standardized geometry and standardized processing has many advantages over non-standardized conventional film. If the patient population for a study is a small, selective group, or if one needs to identify the smallest amount of bone loss in the shortest time, standardized films may be used. Conversely, in a large-scale trial, the use of standardized films may prove to be impractical. Since the advent of personal computer-based image-processing workstations, digital-image analysis has also become a practical tool for clinical trials. Digital subtraction radiography is a highly precise and accurate technique for assessing bony changes associated with periodontal disease. Therefore, advanced digital-imaging systems may be more cost-effective in a clinical trial because the level of precision will have an effect on study length and sample size.