When a cavity is very small, it can be treated conservatively with air-abrasion and a white filling material. The air abrasion technique uses 27-micron silicon dioxide (sand) to clean out the weakened and decayed tooth structure while preserving the surrounding intact structures. Because the particle size of the sand is so small, there is no collateral damage to the tooth. The result is a nearly invisible, very small filling that preserves both the structural integrity of the tooth and the the integrity of the filling material.