High Speed instrument and air abrasion on different dental substrates

Objectives:This study aimed to compare the effectiveness of high speed (HS) and air abrasion (AA) instruments on teeth groups (deciduous, permanent, bovine), concerning preparation time, topography and presence of smear layer. Methods: Each group, consisted of 5 teeth, had their buccal/lingual surfaces prepared by using either HS/AA. All procedures were standardised and timed. Next, the teeth were sectioned and prepared for evaluation of both topography and presence of smear layer on scanning electronic microscopy. Results:Regarding the preparation time, HS yielded preparations 1.5 times quicker than AA did on the three types of dental substrates (Wilcoxon test, p<0.05). In both techniques (Kruskal-Wallis Test, p<0.05) the preparation time was influenced by the dental substrate, particularly in deciduous (Mann-Whitney test with Bonferoni's correction, p<0.017), whose teeth required more time to be prepared. In the descriptive analysis of the topography, no difference was found between the substrates however the instruments used determined distinctive topography. Both techniques showed smear layer (x2 McNemar, p>0.05) in all substrates with different formations. Conclusions:The HS instrument was found to be more rapid than the AA. No difference was found between the three dental substrates regarding both topography and presence of smear layer. The differences found in the present study were only in relation to the effects of each instrument used.