Retention of Resin-Based Pit and Fissure Sealants Placed With Versus Without a Bonding Agent: A Narrative Review

Resin-based pit and fissure sealants are an established, minimally invasive method for reducing occlusal caries risk; however, their effectiveness depends on long-term retention.Acid etching alone does not always achieve complete resin penetration, particularly in narrow or contaminated fissures, and placing a bonding agent beneath the sealant has therefore been proposed to improve retention.PubMed/MEDLINE and the Cochrane Library were searched for studies published between January 1990 and September 2026.Eighteen clinical trials and three systematic reviews comparing resin-based sealants placed with and without a bonding agent were included.Eleven trials reported better retention with a bonding agent, five found no significant difference, one favored omitting it, and in one, the result depended on the adhesive used.The benefit was most consistent when conditions were unfavorable, namely, salivary contamination, hypomineralized or carious enamel, and buccal or palatal fissures.Trials that emphasized optimal placement conditions found no difference.Etch-and-rinse adhesives, and self-etch adhesives applied after phosphoric acid etching, performed better than self-etch adhesives used alone.A 2026 systematic review rated the certainty of this evidence as very low but was limited to one trial design.The present review covers a broader evidence base, examines why the trials disagree, and summarizes the findings as situation-specific recommendations.Current evidence does not support routine use of a bonding agent beneath all resinbased pit and fissure sealants; however, selective application appears beneficial when moisture control or enamel quality compromises conventional sealant retention.