Authors: Bender IB.
Title: Factors influencing the radiographic appearance of bony lesions.
Journal: J Endod
Date: Apr 1982
Citation: 8(4):161-70
Category: Radiology and Imaging
Evidence-based Ranking: 5
Part I- Discussion- There has been many studies that have shown the discrepancies between periapical disease and radiographic evidence. There are also certain factors that can play a role in detection of periapical lesions. These include vertical and horizontal angles. In addition, the summation of thickness of the cortical bone (curvatures in a horizontal and vertical dimension) will alter the detail of the cancellous bone. Demineralizing processes will manifest changes more readily in more calcified tissues. Most studies state that 30-50 % of the mineral content must be lost before radiographic visualization; however these are not applicable to periapical lesions. These lesions depend on the mineral per unit volume of tissue composition, hence the higher the mineral content, the less destruction needed. (cortical bone) Lesions will be seen more readily in the cortex, less in the endosteal region, and least in the cancellous structure. By increasing the time of exposure of KVp, one can enhance visualization.

Part II- Purpose/Objectives: To determine the percentage of mineral bone loss that is required to produce a radiolucent area.

Materials & Methods: Sections of bone from 5 cadaver mandibles were used. The bone was radiographed and lesions were then made in the bone at different areas and sizes with a high speed handpiece. Bone thickness was then measured. Mineral bone loss (MBL) was determined by estimating bone to have 52.5% of inorganic material, and that was multiplied by the percentage of cortical bone lesion in the experimental lesion. The lesions were then observed and categorized into 4 groups; 1. DV- definite regions of black 2. V- definite regions of gray, 3. RV- questionable, 4. NV- no visualization.

Results: The lowest percentage of cortical bone loss producing a radiolucent area was 12.5%., or a MBL of 6.6%. The percentage of MBL in cancellous bone could not be determined with this design.

AuthorÂ’s Conclusion: The highest concentration of mineral per unit volume is located in the periosteal cortex, followed by the endosteal cortex and the cancellous bone. Although it has been stated that 30-50% mineral loss is required before radiographic lesions are evident, these percentages do not apply to local resorptive lesions. The lowest MBL in the direct path of exposure was 6.6%.

Validity of Conclusion / ReviewerÂ’s Comments: Detailed discussion and design which contributed to our current understanding of how lesions appear on radiographs.