EFFECT OF CALCIUM HYDROXIDE PASTE DRESSING ON UNINSTRUMENTED ROOT-CANAL WALL

Dissolution of soft tissues on the uninstrumented root canal wall by a n intracanal dressing of calcium hydroxide paste was examined by scann ing electron microscopy (SEM). The roots of a human extracted teeth we re split longitudinally into halves, and the pulp tissue was removed b y forceps. Then, the halves were divided randomly into three groups. S pecimens in the control group were given no treatment. Specimens of th e 1-wk group were stored for 7 days in calcium hydroxide-saline paste under the condition of 100% humidity and 37 degrees C. Specimens of th e 4-wk group were stored for 28 days in the same manner, but washed an d replaced into new paste every week. Root canal walls of these specim ens were compared under a scanning electron microscope. A layer of odo ntoblasts was observed in the control group, whereas it had disappeare d completely in the 1- and 4-wk groups. However, the predentin remaine d almost intact in the 1-wk group, and although the surface was eroded , in the 4-wk group. It was found that calcium hydroxide paste dressin g could dissolve the odontoblastic cell layer, but had little effect o n predentin.