Continued apical development of pulpless permanent teeth following endontic therapy

Abstract

This was a histologic study of continued apical development in the pulpless permanent teeth of dogs. The vital pulps were exposed to the oral fluids for one week. The root canals were filled with either calcium hydroxide and camphorated parachlorophenol (CMCP) or calcium hydroxide and distilled water. A vital dye, Procion red was injected to demonstrate the formation of calcified tissue. After four months, the animals were sacrificed. Decalcified semi-serial sections were studied. In 31 of 61 pulpless permanent teeth, with incompletely developed roots, continued apical development occurred. Apical calcified tissue resembling cementum was observed in 55 per cent of the specimens treated with calcium hydroxide and CMCP and in 42 per cent of those, with calcium hydroxide and distilled water. Complete closure of the apical foramen was observed in 29 and 11 per cent of the specimens respectively. Inflammation of the periapical tissues was present in 48 per cent of the calcium hydroxide and CMCP group and in 79 per cent of the other group. A significant association was found between the degree of inflammation and apical closure, (P<.001) for the calcium hydroxide-CMCP group, (P<.005) for the calcium hydroxide-distilled water group. The results suggest that calcium hydroxide and CMCP was superior to calcium hydroxide and distilled water and that the addition of CMCP to the paste reduced inflammation. Procion dye was shown to be an effective in vivo dental hard tissue marker.