Comparative evaluation of apical extrusion of sodium hypochlorite gel and solution in primary molars using two different instrumentation techniques: an in-vitro study

Introduction
Sodium hypochlorite solution apical extrusion leads to life-threatening sequelae. Gel-type has been suggested as a safer alternative during intra-canal irrigation due to its’ higher viscosity.

Objective
To compare the apical extrusion of three sodium hypochlorite viscosities in primary molars prepared with two different instrumentation techniques.

Material and methods
This was an in-vitro crossover study. Sixty human primary molar roots were divided into two groups (n = 30), depending on physiological root resorption, and each group was further divided into two sub-groups (n = 15) based on instrumentation technique. Manual instruments (K-file) and rotary files (ProTaper) were used for root canal instrumentation. Each group was irrigated with 5 ml of sodium hypochlorite solution and two different viscosities of sodium hypochlorite gel after preparation. The extruded volume was collected and calculated using Myers and Montgomery model. Statistical analysis was performed by applying Kolmogorov-Smirnov test and Kruskal-Wallis test.

Results
A statistically significant difference was found between sodium hypochlorite solution and gel in manual instrumentation groups. No statistically significant difference was observed between the extruded volumes in the rotary instrumentation groups.

Conclusions
Sodium hypochlorite gel is a safer alternative for primary molars prepared by stainless steel K-file. Preparation technique used in primary molars affects extruded irrigant volume more compared with physiologic root resorption.