Preparation for invasive pit and fissure sealing: air-abrasion or bur?

To evaluate the effect of different air-abrasion devices on substance loss on flattened enamel, preparation extent, and microleakage of invasive pit and fissure sealings.

150 freshly extracted caries-free human third molars were used. 60 teeth (n = 10) were embedded, enamel surfaces were polished to #1200, and six air abrasion devices abraded specimens for 5 seconds. Substance loss was profilometrically recorded as maximum and mean width, and maximum and mean depth. From 90 intact teeth (n = 10), fissures were enlarged by air abrasion (Rondoflex 27 microm/50 microm, Airsonic Mini Sandblaster, CoJet Prep, PrepStart, Primus CPE), or treated with a diamond bur (De Craene), or using a metal bur (Fissurotomy Micro NTF), or with oscillating diamond tips (SONICSeal). Prepared fissures were etched and rinsed and sealed with a light-curing sealant (Helioseal). After four weeks water storage and subsequent 2,000 thermocycles (5 degrees C/55 degrees C), microleakage was assessed with 5% methylene blue for 3 minutes at 30G on cross cuts at x40 magnification. Furthermore the parameters upper fissure width, prepared and unprepared area, penetration depth of the sealer, and area of voids were recorded.

For substance loss on flattened enamel, CoJet Prep and Mini Sandblaster revealed the widest abrasion areas, PrepStart produced the deepest craters (P < 0.05). Regarding preparation characteristics, rotary burs and PrepStart caused significantly less substance loss than the other devices (P < 0.05). Due to the etch&rinse approach, microleakage was generally minimal. Only after air abrasion with Rondoflex (50 microm) significantly less complete sealings were recorded (P < 0.05).