How can the differentiation of internal or external root resorption be best determined?

The differentiation between internal and external root resorption is effectively determined by observing the relationship of the resorption process to the canal and its movement. In the case of external root resorption, the resorptive process typically is seen to communicate with the periodontal space and can be influenced by external factors such as trauma or orthodontic forces. When additional periapical (PA) images are taken, the relationship of the resorptive area to the root canal can be better assessed, allowing the clinician to observe that external resorption may "move" relative to the canal as it progresses, whereas internal resorption, which originates from the pulp chamber, typically expands from within and does not exhibit this same movement relative to the canal.

This distinction is crucial for accurate diagnosis and treatment planning, particularly since the management of each type of resorption can differ significantly. For example, internal resorption might require endodontic treatment, while external resorption might necessitate a different approach based on its etiology.

Using other methods, such as panoramic radiographs or occlusal views, does not provide the same level of detailed information regarding the relationship of the resorption to the pulp canal. Furthermore, while assessing pulpal vitality with an electric pulp tester can give an indication