Ultrasonic root‐end preparation Part 1. SEM analysis

Abstract

Preparations of apical cavities in resected root ends using rotary burs, with and without citric acid rinse, and ultrasonic tips were compared based on the presence or absence of superficial debris and smear layer. Three groups of 20 extracted teeth each were prepared as follows; I, a size 010 round bur was used to prepare an apical cavity 2-3 mm down the long axis of the root; II, treatment as per group I followed by a 60-s rinse with a solution of 10:3 (10% citric acid, 3% Fe2Cl3); and III, an ultrasonic retrotip was used to prepare a 2-3 mm deep apical cavity. Roots were grooved longitudinally, split and prepared for SEM analysis at x100 and x780 magnification. Examiners were calibrated to a standardized grading system. Extensive statistical analyses indicated statistically significant differences within and among the groups (P < 0.05). Root-end preparation with a bur created a heavy smear layer at all levels of the preparation. This layer was partially removed during ultrasonic preparation in the apical two-thirds. A greater removal of the smear layer was achieved with the citric acid rinse (P < 0.05). Coronally, root-end preparations were contaminated with moderate to heavy amounts of debris with all techniques.

The Effects of Two Different Self-Adjusting File Working Times and Three Different Chelating Agents on the Root Canal Filling Bond Strength

“…In the literature, there are some studies that compare the smear layer removal effectiveness of EDTA and CA; however, those findings are contradictory. Certain studies reported that 10% CA is more effective than EDTA (24,25); in contrast, some studies found no significant difference between them (23,26).…”

Current strategy for successful periradicular surgery

“…Root-end bevel is minimal or unnecessary, which decreases the number of exposed dentinal tubules (45,46). Cavity preparations are smaller and cleaner, cavities are deeper and more retentive, and the root-end cavity is better aligned with the long axis of the root canal (47,48). By reducing the risk of root perforation, ultrasonic instrumentation also provides significant advantages in treating deeply fluted roots when an isthmus is present (49,50).…”

Unusual Root Canal Irrigation Solutions

“…13 Different concentrations (1-50%) have been proposed. 14 Gutmann et al 15 concluded that 10% citric acid is better than ultrasound for smear layer removal from the root end cavities. Yamaguchi et al 11 also…”