RDA Practice Exam – California RDA Test Prep & Free Practice Test (2026)

Moisture contamination is the main cause of sealant failures because it can compromise the bond between the sealant and the tooth, leading to leakage and failure. Poor application and using expired materials can also contribute to sealant failures, but they are not the main cause. Patient noncompliance, while important for the success of sealants, is not a factor in causing failures. Therefore, moisture contamination is the most crucial factor to prevent in order to minimize sealant failures.