BEHAVIOR OF THE DENTINARY WALL AGAINST PASSIVE ULTRASONIC AND SONIC IRRIGATION. PRELIMINARY REPORT OF DOCTORAL THESIS.
OBJECTIVES: Evaluate with SEM removal of smear layer and erosion. Instrumentation: Universal Protaper System. Irrigation: acid solutions and active systems. METHODS: 60 premolars were used from dental bank of CEFOUBA. Irrigation: Groups 1 and 2: 5,25% NaOCl. Groups 3 and 4: 5,25% NaOCl + 17% EDTA. Groups 5 and 6: 5,25% NaOCl + 5% Maleic acid. Groups 7 and 8: 5,25% NaOCl + 10% Citric acid. Groups 9 and 10: 5,25% NaOCl + 37% Phosphoric acid. Sonic Activation: Groups 1, 3, 5, 7, 9 and Passive Ultrasonic Activation: Groups 2, 4, 6, 8, 10. 180 MEB 5000X microphotographs were made: 2, 6 and 10 mm from the apex. Removal smear layer and erosion were compared between irrigation-irrigating techniques and between thirds of the canal. Reported number of observations, median, mean, standard deviation, absolute frequency and % of score values. Kruskal-Wallis test was used, with comparisons of post-hoc pairs. RESULTS: There was significant difference in removal between techniques (Kruskal-Wallis test: p <0.05). There was significant difference between groups 1 and 2 (controls) presented lower degree of removal and the rest of groups. There was significant difference between groups 3 or 10 and 6 or 8, the latter had less removal. There was significant difference between groups 8, less removal, and 9 or 10. There was significant difference in erosion between irrigation-irrigating techniques (Kruskal-Wallis test: p <0.05). There was significant difference between groups 1 or 2, less erosion, and groups 3, 4, 7, 8 and 9. There was significant difference between groups 3, 4 or 7 that presented greater erosion and groups 5, 6 or 10, and between groups 7 or 9 and 10 the latter had less erosion. CONCLUSIONS: Techniques SO / 5,25% NaOCl + 17% EDTA and IUP / 5,25% NaOCl + 37% Phosphoric acid produce greater smear layer removal. Irrigation SO / 5,25% NaOCl +17% EDTA produces erosion significantly greater than IUP / 5,25% NaOCl + 37% Phosphoric acid. Techniques SO / 5,25% NaOCl + 5% Maleic acid, IUP / 5,25% NaOCl + 5% Maleic acid and IUP / 5,25% NaOCl + 37% Phosphoric acid produce less erosion. IUP / 5,25% NaOCl + 37% Phosphoric acid provides better balance between removal and erosion. There was no significant difference in removal or erosion between thirds of the canal.