RESUMO
OBJECTIVES: To evaluate the effect of sonic oscillation on penetration depth and marginal adaptation of resin-based fissure sealants. METHOD AND MATERIALS: Thirty-six extracted human third molars were randomized into three groups: in the HF group, teeth were sealed with a filled-resin-based sealant (Helioseal F); in the Sonic-HF group, teeth were sealed with Helioseal F and subjected to sonic oscillation (Compothixo Device, 140 Hz vibration frequency and ± 150 µm amplitude) before curing; in the CO group, teeth were sealed with an unfilled-resin-based sealant (Clinpro). All teeth were thermocycled for 1,500 cycles at 5°C and 55°C, then sectioned buccolingually into four sections (mesial, two middle, and distal). Sections were evaluated under SEM for marginal adaptation and scored. For penetration depth, three independent measurements from each tooth were recorded under SEM, and data were subjected to statistical analysis. RESULTS: The group subjected to sonic oscillation (Sonic HF) resulted in significantly superior penetration depth and marginal adaptation compared with the HF group, but with no significant difference compared with the CO group. CONCLUSIONS: Sonic activation of resin-based sealant increased penetration depth into fissures and marginal adaptation to the enamel wall without decreasing filler load or compromising sealant mechanical properties.