Measuring peri-implant bone lesions using low-dose cone-beam computed tomography.

PURPOSE: High-definition cone-beam computed tomography (HD-CBCT) offers superior image quality at the cost of higher radiation dose compared to low-dose CBCT (LD-CBCT). The aim of this study was to investigate whether peri-implant bone lesions can be accurately quantified using LD-CBCT, even when including the influence of surrounding tissues. METHODS: Twelve titanium implants restored with all-ceramic crowns were placed in bovine bone, and peri-implant lesions were prepared. Radiographic imaging was performed using IR (intraoral radiography), HD-CBCT and LD-CBCT. To simulate the in-vivo situation, the samples were placed inside a dry human mandible, and a second LD-CBCT imaging was performed (LD-CBCT*). The datasets were presented to four observers in random order. Maximum lesion depth and width were measured in a standardized mesiodistal slice in IR, HD-CBCT, LD-CBCT, and LD-CBCT*. Mean lesion depth and width measurements for each sample in HD-CBCT served as reference. RESULTS: Interrater agreement was slight for depth and excellent for width in HD-CBCT and both LD modes. For all observers, measurement deviations from HD-CBCT were below 0.3 mm in the LD protocols (LD-CBCT depth: 0.22 ± 0.17 mm, width: 0.22 ± 0.13 mm; LD-CBCT* depth: 0.24 ± 0.23 mm, width: 0.25 ± 0.21 mm) and at 0.4 mm in IR. CONCLUSION: Absolute differences between LD-CBCT and HD-CBCT are small, although surrounding tissues decrease LD-CBCT image quality. Within the limitations of an in-vitro trial, LD-CBCT may become an adequate imaging modality for monitoring peri-implant lesions at a substantially decreased radiation dose.

In vitro diagnostic accuracy of low-dose CBCT for evaluation of peri-implant bone lesions.

OBJECTIVES: To investigate the in vitro diagnostic accuracy of low-dose cone-beam computed tomography (LD-CBCT) for the detection, classification, and measurement of peri-implant bone lesions. MATERIAL AND METHODS: Titanium dental implants with all-ceramic single crowns (n = 24) were inserted into bovine bone. At twelve implants, four types of peri-implant bone lesions were created. Radiographic imaging was performed using three techniques: LD-CBCT, high-definition CBCT (HD-CBCT), and intraoral radiography (IR). The datasets were presented twice to four observers in a random order. Diagnostic accuracy was measured by calculating sensitivity and specificity, and analyzed using the McNemar's test at a significance level of 0.05. Absolute agreement between the defect sizes was assessed by means of intraclass correlation coefficients (ICC). RESULTS: For all three techniques, diagnostic accuracy and reliability for the detection of defects were almost perfect. The following order was found for classification of the different defect types (sensitivity/specificity): HD-CBCT (0.96/0.99) > LD-CBCT (0.93/0.98) > IR (0.71/0.95). No significant difference was found between the two CBCT techniques. Their performance was superior to that of IR. With regard to absolute agreement of defect size, LD-CBCT agreement with HD-CBCT (ICC, 95% confidence interval) was slight for defect depth (0.342, 0.181-0.625) and substantial for defect width (0.911, 0.775-0.963). CONCLUSION: Intraoral radiography is useful for detecting peri-implant bone lesions. LD-CBCT provides additional information regarding the geometry of defects. The even higher diagnostic accuracy of the HD-CBCT protocol tested needs to be carefully weighed against its radiation dose, which is 14 times higher than that of LD-CBCT.