Ultrasonic abrasion effectivity versus high speed: in vitro study

Objectives:The purposed of this study was to compare the time of action between high speed and ultrasonic abrasion in cavities preparation in bovine's teeth fragments, besides evaluating the microleakage after filling. Methods:Two class V cavity preparation (n=24) with 2,5 x 2,00mm were constructed: one with diamond bur n°1061 (G1=12) and other with CVD tips – UTP 0525 in a sonic device (DMC) (G2=12). The time spended for each cavity were minuted. All of preparations were filled with Z250 (3M) composite, following manufecture's instructions. After imediated finishing and polishing, the fragments were isolated and imerged in a 50% silver nitrate solution. Therafter, the teeth were sectionated to evaluate the leakage rating. This procedure were done by an operator previously calibrated, using the scale: 0 – no stain penetration; cavosurface penetration until 1/3 of the deep in the cavity wall; 2 – penetration between 1/3 and 2/3 of cavity wall; 3 – penetration up the 2/3 cavity wall. Statical analysis was done on the results with the GMC program using Wilcoxon test (p< 0,01). Results:The scale frequency for G1 was 0 – 100%; and for G2: scale 0 – 46%; scale 1 – 9%; scale 2 – 27%; scale 3 – 18%. The time spended in cavity preparation was 7,9 times lower in G1 than G2. Conclusions:The effectivity was superior in high speed than sonic device in time spended in cavitary prepation and less microleakage in the fillings.