Ultrasonic Root-end Preparation with Conventional and CVD Diamond Tips

Objectives: The purpose of this study was to evaluate, using scanning electronic microscopy (SEM), the quality of ultrasonic root-end cavity topography of teeth prepared with chemical vapor deposition (CVD) diamond instruments compared to teeth prepared with conventional diamond instruments and carbide burs in low rotation.

Methods: Thirty extracted single-rooted teeth were used. The canals were cleaned, shaped and obturated using gutta-percha and Sealer 26. The apical thirds were resected at a 45o angle from 3 mm up to the root end. Three different groups of cavity preparation were established: G1: Nac Plus ultrasound using ST12D diamond tip (3 mm deep); G2: same as group 1, but using CVD-HD-680 diamond tip; G3: (control group) conventional rotary micro-motor using #2 smooth spherical bur (3 mm deep). The prepared specimens were observed with SEM at X500, X1000 and X2000 magnification. The presence of debris and smear layer was observed and scores were given.

Results: The best debris and smear layer removal occurred using the two ultra-sonic techniques (Kolmogorov-Smirnov test p<0.05); however best finishing was achieved with the CVD diamond instrument.

Conclusion: A significantly higher smear layer and debris formation was observed by the use of carbide burs when compared with the diamond tips. No significant difference was observed when comparing the CVD and the conventional diamond tips.