Evaluation of lining materials and a new concept for lining: alpha-TCP cement or visible light curing calcium hydroxide composition in composite resin restoration.

Histological studies on the effect of lining methods using a alpha-TCP (TC) and a VLC Dycal (LD) were reported previously. In this report, SEM and electron-probe microanalyzer observations were utilized to determine the effects of lining methods. SEM observations were made on longitudinal sections prepared by a freeze fracture method, using 30 vital dog teeth and 5 vital human teeth. In the LD group, several kinds of crystal growth were seen on surfaces of the material and dentinal wall. In the TC group, the exfoliated space area filled up with rod-shaped crystals. An electron-probe microanalyzer was employed to examine the crystal elements observed in the interface or the exfoliated space area. Our findings indicated that lining appeared to fill the gaps with crystal growth, block stimuli which result from bacterial invasion into the dentinal tubules, and reinforce the superficial dentinal zone.