Calcium Hydroxide Paste UltraCal XS is an aqueous 12.5 pH, radiopaque, calcium hydroxide paste. Use as an endodontic treatment dressing. Calcium hydroxide has been recognized as an anti-bacterial agent due to high pH as well as the ability to potentially stimulate healing of bone. Product Features - The only calcium hydroxide that flows through the NaviTip. - Delivers where needed - Contains 35% calcium hydroxide - Radiopaque