Effect of acid conditioning of root canal dentin on the retention of adhesively luted glass fiber-reinforced composite (FRC) posts.

PURPOSE

To assess the retention of glass FRC posts luted with resin cements after conditioning the canal dentin with different acidic treatments.

METHODS

Post spaces were prepared in six groups of eight endodontically treated extracted teeth. Glass FRC posts were luted after etching the canal dentin with phosphoric acid and/or applying ED-Primer, Clearfil New Bond or XP Bond. The groups with their respective etching time, primer and cement combinations were as follows. ED: ED-Primer only and Panavia 21; ED15: 15 seconds phosphoric acid treatment, ED-Primer and Panavia 21; NB15: 15 seconds phosphoric acid treatment, Clearfil New Bond and Panavia 21; NB30: 30 seconds phosphoric acid treatment, Clearfil New Bond and Panavia 21; XP15: 15 seconds phosphoric acid treatment, XP Bond and Calibra; XP30: 30 seconds phosphoric acid treatment, XP Bond and Calibra. Specimens were stored in water for 30 days and subjected to simulated aging conditions. Post retention was measured in tension at a crosshead speed of 2 mm/minute. Analysis of variance and Bonferroni multiple range tests were conducted for data analysis.

RESULTS

The mean (standard deviation) retention values in Newtons (N) were: ED: 180.9 (44.9); ED15: 278.3 (37.7); NB15: 283.8 (84.9); NB30: 187.7 (60.0), XP15: 216.8 (46.8), XP30: 199.6 (34.0). The retention values of ED15 and NB15 were significantly higher than those of ED and NB30 groups respectively. There were no statistically significant differences between XP Bond groups. Microscopic evaluation of post surfaces demonstrated that the debonding failure was adhesive at the cement-post and cement-dentin interfaces.