Sealants: Patient Selection, Isolation, Etching, and Placement
Sealants are a core preventive function on the DANB CPFDA exam. The test asks you to decide when a sealant is appropriate, how to isolate and etch the tooth, how to place and cure the material, and how to recognize conditions that make sealing unsafe. You must also distinguish a preventive sealant from a restoration and know why retention fails.
Patient selection and assessment
- Best candidates are permanent molars and premolars with deep pits and fissures, especially newly erupted teeth in children and adolescents at caries risk.
- Seal caries-free or non-cavitated surfaces; a frank cavitation involving dentin is restored, not sealed.
- Primary molars may be sealed when fissures are deep and the child is at risk, but the tooth must be isolatable and the child cooperative.
- Check eruption: a partially erupted tooth may be impossible to keep dry, so consider postponing.
- Reassess sealants at recall; replace partial sealants and repair voids.
Technique rules
- Isolate with cotton rolls, dry angles, and suction; moisture control is the biggest determinant of retention.
- Etch enamel with phosphoric acid gel, commonly 15–30 seconds, following the manufacturer’s time; rinse thoroughly and dry to a frosty white appearance.
- If saliva or moisture contaminates the etched surface, re-etch; do not place sealant over a contaminated surface.
- Apply sealant into fissures, work out bubbles, avoid overfilling, light-cure as directed, then check occlusion and remove excess.
- Floss after placement to confirm no interproximal excess.
Worked example
A 7-year-old has a newly erupted permanent first molar with deep, stained fissures and no cavitation. The assistant isolates the tooth with cotton rolls and suction, etches for 20 seconds, rinses, and dries. The enamel looks frosty. The assistant applies resin sealant, cures, checks that the bite is not high, and flosses. Because the tooth was isolated and dry, retention is likely.
Traps
- Sealing a cavitated lesion and calling it prevention.
- Etching a wet tooth or letting the patient close on saliva.
- Using a fluoride-containing prophy paste immediately before etching without rinsing.
- Forgetting to check occlusion, leaving a high spot.
- Re-etching only briefly after contamination instead of repeating the etch.