Influence of Ultrasound, With and Without Water Spray Cooling, on Removal of Posts Cemented With Resin or Zinc Phosphate Cements

Abstract

The efficacy of ultrasound, with and without water spray, was evaluated in vitro on the amount of force necessary to dislodge posts cemented with resin or zinc phosphate. Forty-two samples were divided into six groups: groups 1, 2, and 3, posts cemented with zinc phosphate; groups 4, 5, and 6, posts cemented with resin (Panavia F); groups 1 and 4 (controls), no ultrasound; groups 2 and 5, ultrasound without water spray; and groups 3 and 6, ultrasound with water spray. The Instron testing machine was used. Ultrasound without water spray significantly reduced (71%) the force necessary to displace posts cemented with Panavia F (p < 0.01); however, this value was similar to the efficacy of ultrasound with water spray for posts cemented with zinc phosphate (reduction of 75%). We conclude that cooling with ultrasound interferes with the force necessary for post removal, depending on the type of cement used.

Efficacy of ultrasound in removal of intraradicular posts using different techniques

“…According to Berbert et al (13), the use of ultrasound for 2 and 5 min reduces the force necessary to remove cast metal posts cemented with zinc phosphate by 30-35% when compared to removal of the same type of intraradicular posts without ultrasound. Garrido et al (14), however, used resin cement in a similar trial and did not find any statistically significant difference between the group for which ultrasound and irrigation were used and the group for which ultrasound was not used.…”

“…Tukey critical value = 0.73135. alternative technique for removal, either alone or in combination with other techniques (9)(10)(11)(12)14). The development of improved procedures for currently used techniques is as important as the development of new techniques.…”

Ultrasonics in Endodontics: A Review of the Literature

“…Resin cements are not friable and do not tend to produce microfractures due to ultrasonic vibration (106). It was suggested that the absence of a water spray seems to increase the action of US when applied to posts cemented with resin cements, possibly because of the increase in heat (107). This is helpful information, as it has been observed that the capacity of adhesion of a resin cement, and consequently mechanical retention, gradually reduces with the number of thermal cycles (108).…”

Factors Affecting Temperature Rise on the External Root Surface During Ultrasonic Retrieval of Intracanal Separated Files

“…Serious bone damage was shown at higher temperatures or for longer application times. Many in vitro studies have measured the TR on the external root surface during the removal of intracanal posts using ultrasonic devices (22)(23)(24)(25). Three cases of severe burn injuries after ultrasonic removal of posts were reported (26).…”