Effects of Dentin Moisture on Cementation of Fiber Posts to Root Canals

Achieving optimal moisture inside the root canal is a challenge during bonding of fiberglass posts. This study evaluated the effect of different moisture patterns on the push-out bond strength (PBS) and nanoleakage (NL) of fiber posts bonded to the root canal of two simplified etch-and-rinse adhesives.

The roots of 72 human premolars were endodontically prepared and divided into 6 groups according to the combination of the main factors: adhesive (Ambar and Adper Single Bond 2) and moisture (dry, wet, and overwet). The posts were cemented and after 1 week, the roots were cross sectioned into 6 disks. Two disks each were obtained from the cervical, middle, and apical thirds, and the PBS test was carried out (0.5 mm/min; n = 8). The NL was evaluated by scanning electron microscopy after the immersion of specimens in 50% silver nitrate (n = 4). The failure pattern was examined on all debonded specimens. Data were analyzed by three-way repeated measures ANOVA and Tukey's test (5%).

For both adhesives, higher PBS values and lower NL were observed in the wet groups, and lower PBS and higher NL in the dry group. In general, the overwet condition showed intermediate results.

The root dentin walls should be left slightly moist before performing fiber post cementation procedures.