The aim of this study was to examine the results of electronic root canal length measurement (ERCLM) with resistant-type device on an experimental model of dogs at various stages of pulpitis and apical periodontitis. Six mongrel dogs were experimental and two served as a control.We induced pulpitis and periapical periodontitis on premolar teeth by pulp exposure and left pulp chambers open. In all animals we performed ERCLM at first experimental day, when pulp was healthy, and 20, 35, 50 and 65 days after pulp exposure. The results showed that the worse result was at healthy pulp (-2, 24   3, 29 mm shorter then cemento-dentinal junction(CDJ). Roentgenographic examination showed that periapical radiolucency was present already 20 days after pulp exposure.The results after 20, 35 and 65 days were not statistically significantly different (t-test, p> 0, 05) and vary from 1, 26 mm shorter then CDJ to 2, 07 mm longer then CDJ, in the periapical tissue. The results after 50 days of pulp exposure showed statistically significant difference (t-test, p< 0, 05) in comparison to other experimental groups ( dif -2, 27  2, 65 mm), but not statistically significant difference to the control group (t-test, p> 0, 05). We presumed that the reason for that phemonenon was maintaned vitality of the pulp in some canals which influenced the results. We conclude that duration of apical periodontits do not influence the results of ERCLM on dogs teeth when pulp chamber was left open for dreinage and transitional concentration zone formed in the region of apical foramen.

Dental Medicine