Effects of the vertical projection angle in intraoral radiography on the detection of furcation involvement of the mandibular first molar
To investigate the effects of vertical projection angle alterations in intraoral radiography on the detection of furcation defects in the mandibular first molar, and to clarify the possible cause of variations in detectability.
Five bilateral first molars of dried mandibles were used as a furcation disease model. Simulated defects of different depths were created in a stepwise manner, and intraoral radiographs were taken using different vertical angles of the X-ray beam. A total of 858 radiographs were incorporated into the statistical analysis. The simulated defects were divided into four groups according to the depths acquired from cone-beam computed tomography examinations. The detectability of the extent of each loss of bone was calculated as the area under the curve using a receiver-operating characteristic analysis.
Small defects were less detectable than larger defects, and the upper angle (20°) resulted in the best detectability. The detectability of larger defects was high throughout all the angles, with the exception of extremely low angles.
Diagnostic accuracy was affected by the vertical angle of the X-ray beam. An angle that avoids the cortical bone wall would improve the ability to detect and diagnose small defects.
KeywordsDental radiography Furcation defects ROC curve Cone-beam computed tomography
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