Estudo in vitro da quantidade do uso de pontas de ultrassom na eficiência da remoção de retentores metálicos

Abstract

The present study evaluated in vitro the influence of the amount of use of ultrasound tips on the efficiency of removal of metallic retainers. Fifty endodontically treated upper canines received fused metal retainers cemented with zinc phosphate cement. The specimens were randomly randomized into 5 groups (n = 10), according to the removal protocol to which they

were submitted: G I (control) - Ultrasonic vibration using Remo C NOVA tip; G II- Ultrasonic vibration using Remo C tip used 3 times; G III- Ultrasonic vibration using Remo C

tip used 5 times; G IV- Ultrasonic vibration using Remo C tip used 7 times; G V- Ultrasonic vibration using Remo C tip used 9 times. The vibration protocol was 15 seconds on each face (buccal, palatal, mesial and distal) totaling 1 minute, being the ultrasound Jetsonic Duo, chosen for use under refrigeration. All specimens were subjected to tensile testing on the Universal Testing Machine at a tensile speed of 1 mm / min until complete removal of the root wall retainer. The maximum tensile force required for intrarradicular retainer removal was recorded in Newtons. The recorded values were submitted to statistical analysis using the Bioestat 5.0 program and normality tests and parametric and non-parametric tests were performed with a 5% significance level. Normal values were found (Shapiro Wilk) and ANOVA variance test was applied, with statistical difference (p.0051) P <0.05. TUKEY test was performed and it was verified that groups 1 and 2 had the lowest means of traction force (1-103N; 2- 104N) when using Nova tip and used 3x and the highest average 190N when used 9X tip (group 5). A statistical difference was found between groups 1 and 5 (p <0.05) and groups 2 and 5 (p <0.05), with no difference found in the other groups tested. The study highlights the importance of renewing the ultrasound tips to optimize ultrasonic efficiency. A new tip is used up to 7 times maximum.