The Bitewing radiograph is most effective for identifying interproximal caries in posterior teeth because it provides a clear, detailed view of the crowns of the upper and lower teeth simultaneously, especially the areas between teeth where caries commonly develop. It allows for optimal visualization of contact points and enamel-dentin junctions without superimposition of other anatomical structures. This makes it superior to periapical, occlusal, or panoramic radiographs, which either show limited interproximal detail or lack sufficient resolution. Bitewings are the standard radiographic technique for detecting early and hidden interproximal lesions in posterior dentition with high diagnostic accuracy.

Reference: White and Pharoah, Oral Radiology: Principles and Interpretation, 8th Edition.