What is the primary cause of failure of sealant retention?

• A. Moisture contamination
• B. Inadequate etching
• C. Thermal expansion
• D. Over-curing

Answer: (A)

Moisture contamination is the main factor that undermines sealant retention because sealants rely on intimate wetting and mechanical interlock with etched enamel. If saliva or other moisture is present during placement, the resin cannot properly flow into and adapt to the fissure walls, producing voids and incomplete sealing. Water at the interface also interferes with polymerization, weakening the bond and promoting microgaps that allow leakage and early sealant loss. While inadequate etching can reduce retention, moisture has the most direct and frequent negative impact in the clinical setting. Thermal expansion or over-curing do not typically drive sealant retention failure in routine practice.