Fissure sealants: retention depends on isolation, not on the material chosen

The sealant is one of the preventive interventions with the best cost-benefit ratio, and one in which the result depends almost entirely on execution.

The indication concerns deep, retentive fissures of permanent molars, particularly in the years after eruption, when risk is highest and enamel not yet fully matured.

Patient selection matters as much as tooth selection. In a low-risk child with shallow fissures the benefit is modest; in a high-risk child with deep fissures it is substantial.

The factor determining sealant longevity is not the material but the isolation during application. Saliva contamination during etching or placement compromises adhesion irreversibly.

Rubber dam is ideal, but on a partly erupted molar in a young child it is often impracticable. In such cases well-managed cotton rolls and suction are an acceptable compromise.

The partly erupted molar is the most difficult and most frequent situation, because the gingival tissue covering part of the distal surface makes isolation precarious precisely where risk is high.

Under these conditions glass ionomer is preferable to resin. It has lower adhesion but tolerates moisture better, and releases fluoride: it behaves as a temporary sealant protecting until eruption permits a resin.

Resins have superior retention and are the choice where isolation is achievable. The difference in longevity between the two materials under ideal conditions is marked.

Sealing early non-cavitated lesions is a practice supported by the evidence and still little applied. A sealant over an early lesion isolates it from its substrate and arrests progression.

It requires certainty that no cavitation is present, however, and that depends on the quality of the diagnosis. Where there is doubt, radiography guides better than visual inspection.

Periodic review is the part of the protocol that gets lost. A partly detached sealant is worse than no sealant, because it creates a protected niche where plaque stagnates.

Checking with a probe at every recall and repairing partial sealants is what turns a one-off intervention into lasting protection.

In summary: isolation determines retention more than the material does, glass ionomer is preferable on partly erupted molars, sealing early lesions is supported but requires a confident diagnosis, and periodic review is part of the treatment.