Apical sealing efficacy of two reverse filling techniques versus cold-burnished Gutta-percha

The apical seal produced by the cold-burnished gutta-percha method and two amalgam reverse filling techniques was investigated in an in vitro study using 36 extracted human single-rooted teeth. Following root canal obturation, 27 teeth were divided into three experimental groups and each group was subjected to one of the three following filling techniques: (a) cold-burnishing of gutta-percha; (b) amalgam reverse filling; and (c) amalgam reverse filling in conjunction with cavity varnish. The remaining nine teeth served as controls (4). The teeth were placed in methylene blue dye for a period of 1 wk, after which they were retrieved, washed, sectioned, and the apical dye penetration measured. The results showed that amalgam with cavity varnish demonstrated less dye penetration than the other experimental groups. The difference was statistically significant (p less than 0.0001).