Gen Dent. 2026 Jul-Aug;74(4):65-68.
ABSTRACT
The aim of this in vitro study was to evaluate the surface roughness of microhybrid and nanohybrid composite resins subjected to polishing procedures immediately after curing or after 24 hours of immersion in distilled water. Two groups, comprising a total of 60 disc-shaped (10 × 2-mm) specimens, were prepared using microhybrid and nanohybrid composite resins (n = 30 per material) and further categorized into subgroups based on the polishing protocol. Specimens were fabricated by packing the appropriate composite resin into a cylindrical mold, compressing the material between transparent polyester film strips at both ends, and curing each side of the specimen with an LED light for 40 seconds. All specimens were finished immediately after polymerization using a 12-fluted tungsten carbide bur in a high-speed handpiece for 15 seconds under water cooling. The specimens in each material group were then divided into 2 subgroups (n = 15 each). One subgroup was polished immediately after finishing; the other was stored in distilled water at 37°C in a dark environment for 24 hours prior to polishing. Polishing was performed using a planar motion with 10 strokes at a low speed of 12,000 rpm, applying light pressure for 30 seconds. Surface roughness (Ra) was analyzed with a profilometer. Independent t tests were performed to compare the Ra data of the groups, and values of P < 0.05 were considered statistically significant. The Ra values of nanohybrid specimens were significantly lower than those of microhybrid specimens, regardless of whether polishing was performed immediately or delayed. Delayed polishing significantly reduced the Ra values of both materials. Nanohybrid composite resins demonstrated superior polishability and surface smoothness, making them a preferred choice for both immediate and delayed polishing.
PMID:42329616
