Sonic versus ultrasonic activation for removal of calcium hydroxide from curved root canals: an in vitro study.

Abstract

To compare the remaining calcium hydroxide (Ca(OH)2 ) coated area in the apical third of curved canals after sonic and ultrasonic activation using Scanning Electron Microscope (SEM). Permanent mandibular molars were collected. Those which radiographically presented a curvature between 15º and 30° in the mesial root were included. A total of 39 mesiolinguales canals were instrumented with rotary ProTaper and filled with Ca(OH)2 mixed with propylene glycol. They were randomly divided into three groups according to the type of removal. Group I: three inserts with File F2 and 2ml of 5.25% sodium hypochlorite (NaOCl) irrigation between each insertion. Group II: three sonic activations, irrigattion with 2ml of 5.25% NaOCl between activations. Group III: three ultrasonic activations irrigating with 2ml of 5.25% NaOCl between activations. Three root canals were left without filling and other three were completely filled as positive and negative control, respectively. Then, they were fractured lengthwise to get two sections. The apical third of the root canal of each section was taken x-rays with SEM and subsequently, in an area of 100.000um2, the remaining Ca(OH)2 coated surface from both sections was measured using ImageJ 1.47. They were analyzed with one-way ANOVA using Graph Pad-Prism (5.01). The percentage of the remaining Ca(OH)2 coated area in group I was 62.93%, 51.77% in group II, and 58.90% in group III. There were no significant differences between the three groups (p>0.01). There are no significant differences in the percentage of the remaining Ca(OH)2 coated area in the apical third of curved root canals when comparing sonic and ultrasonic activation using SEM.

Keywords

• Endodontics
• Calcium hydroxide
• removal
• Sonic
• Ultrasonic.