Final answer:
Periapical radiograph is excellent for determining the extent of crestal bone loss.
Step-by-step explanation:
The type of radiograph that is excellent for determining the extent of crestal bone loss is the periapical radiograph. Periapical radiographs are well-suited for assessing the extent of crestal bone loss around individual teeth. These radiographs capture the entire tooth, including the root and surrounding bone. They provide detailed images of the tooth from crown to root apex, making them valuable for evaluating conditions such as periodontal disease and detecting changes in the supporting bone structure. Panoramic radiographs (Option 2) offer a broader view of the entire dental arch but may not provide the same level of detail for assessing localized crestal bone loss as periapical radiographs.