Fernando Henrique Westphalen

Absorbed doses in salivary and thyroid glands from panoramic radiography and cone beam computed tomography

Introduction: Panoramic radiography and cone beam computed tomography (CBCT) are very important in the diagnosis of oral diseases, however patients are exposed to the risk of ionizing radiation. This paper describes our study aimed at comparing absorbed doses in the salivary glands and thyroid due to panoramic radiography and CBCT and estimating radiation induced cancer risk associated with those methods. Methods: Absorbed doses of two CBCT equipment (i‐CAT Next Generation and SCANORA 3D) and a digital panoramic device (ORTHOPANTOMOGRAPH OP200D) were measured using thermoluminescent dosimeters loaded in an anthropomorphic phantom on sublingual, submandibular, parotid and thyroid glands. Results: Absorbed doses in the i‐CAT device ranged between 0.02 (+/‐0.01) and 2.23 mGy (+/‐0.03), in the SCANORATM device ranged from 0.01 (+/‐0.01) to 2.96 mGy (+/‐0.29) and in the ORTHOPANTOMOGRAPH OP200D ranged between 0.04 mGy and 0.78 mGy. The radiation induced cancer risk was highlighted in the salivary glands, which received higher doses. The protocols that offer the highest risk of cancer are the high resolution protocols of CBCT equipment. Conclusion: CBCT exposes patients to higher levels of radiation than panoramic radiography, so the risks and benefits of each method should be considered. The doses in CBCT were dependent on equipment and exposure parameters, therefore adequate selection minimizes the radiation dose.

Accuracy of Digital Periapical Radiography and Cone-beam Computed Tomography for Diagnosis of Natural and Simulated External Root Resorption

Introduction: The aim of this study was to compare the sensitivity and specificity of digital periapical radiography and cone‐beam computed tomographic (CBCT) imaging in the detection of natural and simulated external root resorptions (ERRs) with micro–computed tomographic (micro‐CT) imaging as the reference standard. Methods: One hundred twenty‐six teeth were scanned using the SkyScan 1172 micro‐CT scanner (Bruker microCT, Kontich, Belgium), and the images were evaluated using NRecon software (Bruker microCT). After micro‐CT imaging, the teeth were divided into 3 groups: control, 42 teeth that did not present any ERR cavities; natural, 42 teeth that presented 1 or more ERR cavities; and artificial, 42 teeth without ERRs but perforations were created to simulate the cavities. Ortho‐, mesio‐, and distoradial digital periapical radiographs and CBCT images were obtained, and the images were evaluated by 2 double‐blinded qualified radiologists. Results: The sensitivities and specificities for the radiographic and tomographic methods were 78.18% and 97.27% and 59.52% and 97.62%, respectively. Within the individual groups, both methods had lower sensitivity and specificity for natural and artificial resorptions, and the differences were statistically significant. Conclusions: CBCT imaging was the best method for the detection of ERRs. Only 74.5% of natural ERR gaps were observed on the digital periapical radiographs and 94.5% on CBCT imaging; in the artificial group, this number increased to 81.8% and 100%, respectively. The configuration of the natural ERR gaps is different from those artificially simulated and is much more difficult to observe. Highlights:This study compared the sensitivity and specificity of digital periapical radiography and cone‐beam computed tomographic (CBCT) imaging in the detection of natural and simulated external root resorptions (ERRs) with micro–computed tomographic imaging as the reference standard.Both methods had lower sensitivity and specificity for natural resorptions compared with artificial resorptions, and the differences were statistically significant.CBCT imaging was the best method for the detection of ERRs.Only 74.5% of natural ERR gaps were observed on digital periapical radiographs and 94.5% on CBCT imaging; in the artificial group, this number increased to 81.8% and 100%, respectively.The configuration of the natural ERR gaps is different from those artificially simulated and is much more difficult to observe.

Accuracy of linear measurements performed with two imaging software in cone-beam computed tomography scans of dry human mandibles

The present study aimed to assess the accuracy of linear measurements performed with two software packages in multislice (MSCT) and cone beam (CBCT) computed tomography (CT) images. The sample consisted of 10 human mandibles marked standardly 8 times with metallic orthodontic wires. The mandibles underwent both MSCT and CBCT scanning and were measured linearly and digitally with two software packages, namely Studio 3.1® (Anne Solutions®, SP, Brazil) (ST) and Implant Viewer 2.817® (Anne Solutions®, SP, Brazil) (IV). The linear measurements were the mandibular height (MH) and width (MW), and the distance from the alveolar ridge to the mandibular canal (AC). To validate the measurements, the mandibles were sectioned in the marked regions and measured with a digital caliper. Statistically significant differences were not observed between the measurements (MH, MW, and AC) taken digitally with the two software packages from images obtained from the two scanning modalities (MSCT and CBCT) and the measurements taken manually with a digital caliper (p>0.05). MSCT and CBCT images measured digitally with ST and IV software packages resulted in reliable outcomes when compared to measurements obtained manually. Both software and imaging modalities are reliably useful for planning surgical procedure in the dental practice.