Comparative Safety of Needle, EndoActivator, and Laser-Activated Irrigation in Overinstrumented Root Canals

OBJECTIVE

To evaluate the safety of sodium hypochlorite (NaOCl) irrigation using three different techniques during the final rinse in overinstrumented root canals.

BACKGROUND DATA

The effect of irrigant activation on irrigant extrusion from overinstrumented root canals is still unclear.

METHODS

A total of 30 single-rooted teeth were decoronated. The working lengths were determined and the roots were divided into two groups of 15 teeth each: group 1, instrumentation 0.5 mm short of the apical foramen and group 2, instrumentation 0.5 mm beyond the apical foramen (overinstrumented). Needle irrigation (NI), sonic irrigation with EndoActivator (EAI), and laser-activated irrigation (LAI) were used for the final rinse in each group; each root underwent the three irrigation procedures in a randomized crossover manner. A modified container-foam model was used to collect apically extruded NaOCl. The weight of the extruded NaOCl was calculated by subtracting the initial weights of the containers from their final weights. All data were statistically analyzed.

RESULTS

The amount of NaOCl extrusion was similar with all three irrigation systems in group 1. In group 2, the amount of extruded NaOCl was significantly greater with EAI than with NI and LAI. EAI and LAI caused significantly greater extrusion in group 2 than in group 1.

CONCLUSIONS

EAI, NI, and LAI are equally safe for irrigating canals with intact apices. However, the risk of irrigant extrusion can increase in overinstrumented canals, with EAI associated with a greater risk compared with NI and LAI.

Comparison of calcium hydroxide removal by self-adjusting file, EndoVac, and CanalBrush agitation techniques: An in vitro study

Objectives:

This study comparatively evaluated the efficacy of self-adjusting file (SAF), Endovac, and CanalBrush irrigant agitation protocols in removing calcium hydroxide (Ca(OH)₂) from the root canals.

Materials and Methods:

Sixty extracted human mandibular canine teeth were instrumented with ProTaper rotary instruments to size #40 and dressed with Ca(OH)₂. The roots were randomly assigned to four groups according to irrigant agitation protocol used (n = 15). In Group 1: Conventional syringe irrigation (no activation, control); Group 2: Rotary brush agitation (CanalBrush); Group 3: Apical negative pressure irrigation (EndoVac system); and Group 4: Sonic agitation (SAF) were used. Scanning electron microscopic (SEM) evaluation was done for assessment of Ca(OH)₂ removal in the coronal and apical thirds. Statistical analysis was performed by Wilcoxon and Kruskal-Wallis tests.

Results:

There were statistically significant differences among the groups (P = 0.218). A statistically significant difference was seen between the test groups in Ca(OH)₂ removal from the apical third of the canal (P < 0.05). In the coronal third, there was no difference between the groups (P > 0.05). The most efficient Ca(OH)₂ removal in apical third was recorded in Group 3 (EndoVac) and Group 4 (SAF) (P < 0.05). In Group 4 (sonic agitation), there was no significantly difference between Ca(OH)₂ removal in coronal and apical thirds.

Conclusions:

SAF and EndoVac showed significantly better performance than CanalBrush and conventional syringe irrigation in removing Ca(OH)₂ from apical third of the root canals.