PH CHANGES AT THE SURFACE OF ROOT DENTIN WHEN USING ROOT-CANAL SEALERS CONTAINING CALCIUM HYDROXIDE

The purpose of this study was to investigate longterm pH changes in ca vities prepared in root surface dentin of extracted teeth after obtura tion of the root canal with gutta-percha and a variety of sealers cont aining calcium hydroxide. After cleaning and shaping, root canals in 5 0 recently extracted, human single-rooted teeth were divided into five groups. Each of four groups was obturated with gutta-percha and eithe r Sealapex, Sealer 26, Apexit, or CRCS, all of which contain calcium h ydroxide. The remaining group sewed as the control and was not obturat ed with gutta-percha or sealer. Cavities were prepared in the facial s urface of the roots in the cervical and middle regions. The pH was mea sured in these dentinal cavities at the initiation of the experiment, and 3, 7, 14, 21, 28, 45, 60, 90, and 120 days after obturation. Resul ts indicate that the pH at the surface of the root does not become alk aline when calcium hydroxide cements are used as root canal sealers. R egardless of the sealer used, the observed pattern of pH change was no t different from that seen in the control group of roots that were not treated with sealer. It is concluded that calcium hydroxide-containin g cements, although suitable for use as root canal sealants, do not pr oduce an alkaline pH at the root surface. If such a pH change is relat ed to treatment of root resorption, these sealants do not contribute t o this treatment.