In vitro computer analysis of crown discolouration from commonly used endodontic sealers

The aim of this study was to assess the degree of staining of tooth crowns by commonly used endodontic sealers using a computer analysis method. Crown discolouration by root canal sealers AH26, Endofill, Tubliseal, Zinc oxide eugenol (ZnOE), Apatite root canal sealer III as well as gutta-percha and Cavizol (a filling material containing ZnOE) were tested on extracted human premolar teeth. The roots of the teeth were resected 3 mm below the cemento-enamel junction. The pulp chambers were then cleaned and irrigated. The samples were divided into nine groups of five samples each and filled with test materials. Ten teeth were used as control groups: five positive (amalgam) and five negative (distilled water). The degree of tooth discolouration was analysed at 3, 6 and 9 months. The crown discolouration was assessed by computer analysis of digital images taken from the samples using the CIE Lab colour system. Statistical analysis was carried out using anova, repeated measure anova and Tukey's HSD tests. All sealers caused a degree of tooth discolouration, which increased with time. Endofill and ZnOE caused the greatest discolouration and Apatite root canal sealer III caused the least discolouration after 9 months. The most discolouration during the test periods occurred in the cervical third of the crown.