Vertical angulation of the X-ray beam and radiographic diagnosis of secondary caries

The purpose of this study was to assess to what extent angulation of an X-ray beam could affect the quality of diagnoses of caries adjacent to restorations with different radiopacities. Amalgam and composite class II restorations with and without secondary caries were done in extracted teeth. The teeth were radiographed using four different vertical angulations -0, 5, 10, and 15 degrees. Eight dentists diagnosed caries lesions on these radiographs. The best diagnostic outcome was found for the composite restorations radiographed at 10 degrees vertical angulation. Diagnosis was generally better for lesions marginal to composites compared to amalgams. The quality of secondary caries diagnosis in connection with amalgam was not significantly affected by variations in vertical angulation from 0 up to 15 degrees.