American Board of Orthodontics (ABO) Practice Exam 2026 – All-in-One Resource to Master Your Orthodontics Certification!

Ankylosed primary molars are teeth that have fused to the underlying alveolar bone and typically do not exhibit the normal mobility and percussion sensitivity associated with healthy molars. The percussion test, which involves tapping on the tooth to assess sensitivity and sound, can yield unreliable results when diagnosing ankylosis. This is because the fusion of the tooth to the bone can alter how sound travels and how the dentist interprets the clinical findings.

On the other hand, visual examination, digital palpation, and radiographic assessment can provide more definitive information. Visual examination can help identify clinical signs such as supraclusion or a lack of mobility, while digital palpation can provide tactile feedback regarding the condition and positioning of the tooth. Radiographic assessment allows for a clearer view of the surrounding structures and can reveal signs of ankylosis, such as a lack of periodontal ligament space.

Thus, the percussion test is deemed less reliable compared to these other methods, making it a less effective tool in diagnosing ankylosed primary molars.