(i) whether ultrasonic vibration reduces the amount of tensile force required to remove a prefabricated titanium post luted with a resin cement; and
(ii) whether obturation with gutta-percha and a eugenol sealer compromises the retention of cemented posts, compared with teeth obturated with gutta-percha and a eugenol-free sealer control.
•N= 96 extracted canines.
•Teeth were decoronated, accessed, and instrumented using Series 29, .04 taper Profile rotary instruments to an apical preparation size #8 (ISO 60). •the canals were obturated with laterally condensed GP and and one of two different sealers—Roth’s 801 Elite Grade cement, a sealer containing eugenol, or AH26, an epoxy resin sealer containing no eugenol.
•After 2 weeks, a 9-mm post space was created in each tooth for a #6 parallel-sided titanium Parapost.
•the teeth were then divided into 8 groups according to the sealer (Roth’s or AH26) and the cement used (zinc phosphate or Panavia 21 resin cement). (Fig.1)
•After 2 weeks, the teeth were mounted in acrylic, ultrasonic energy was applied to the post– dentin interface for a total of 16 min using P5 ultrasonic unit at maximum power.
•The subsequent tensile force required to dislodge each post was determined on an Instron Universal Testing Machine
Most highlighted Results:
•there was a significant difference in the forces required to dislodge the posts based on the sealer used. The use of AH26 significantly increased the retention of the posts, compared with the Roth’s sealer.
•the groups subjected to US vibration exhibited significantly higher values of the forces required for post dislodgment than those in which no vibration was used.
•The differences for cement were not statistically different.
In cases of well-adapted long posts, specially if cemented with resin cement, the use of ultrasonic vibration may be ineffective in post removal. other treatment options may be considered.