Solubility and biocompatibility of calcium hydroxide-containing root canal sealers

Abstract The solubility and biocompatibility of 2 commercially available calcium hydroxide-containing root canal sealers, CRGS and Sealapex, were studied. Four dogs were anesthetized and a sulcular incision was made to expose the vestibular surface of the mandble. Two rows of holes, 2 mm deep, 2 mm wide and 10 mm apart, were drilled into the mandible. Teflon cups with the same dimensions as the holes were filled with the experimental materials and placed in the cavities. For the purpose of comparison, Teflon cups filled with a traditional zinc oxide-eugenol sealer and a paste of calcium hydroxide and saline were implanted as well. After 90 days the animals were killed. The mandibles were dissected free, fixed in formalin and demineralized. Bone specimens containing 1 Teflon cup were then embedded in paraffin, sectioned longitudinally, and the sections were stained with hematoxylin and eosin and examined in the light microscope. The cups which originally contained the paste of calcium hydroxide and saline were completely filled with bone. Sealapex was partly missing from the cups and was generally replaced by ingrowth of connective tissue. Large amounts of the material were seen in macrophages and tissue outside the cups. CRCS and the traditional zinc oxide-eugenol sealer generally filled the cups well after 3 months. Tissue fluids were seen in the superficial layers of these materials, but ingrowth of tissue had not occurred. No macrophage reaction was seen with either of these materials, but a stronger inflammatory reaction was caused by CRCS than by the traditional zinc oxide-eugenol cement. CRCS appeared to be the most stable of the calcium hydroxide-containing sealers tested.