Effect of customization of master gutta‐percha cone on apical control of obturation using different techniques: an in vitro study

Abstract

Aims (i) To compare the prevalence of root filling extrusion placed using three different obturation techniques, each with or without customization of the master gutta‐percha cone; and (ii) to investigate the effects of various factors on the prevalence of root filling extrusion.Methodology A total of 180 roots were selected and randomly allocated into three groups. Five general dental practitioners were recruited; each obturated one group of the roots using three techniques, namely cold lateral condensation (n = 20), Schilder's warm vertical condensation (n = 20) or continuous wave condensation (n = 20). Each technique was completed with (n = 10) or without (n = 10) customization of the master gutta‐percha cone using chloroform. Two groups of the roots were recycled to allow all five operators to use them. Two observers examined the preinstrumentation, working length, master apical file and postobturation radiographs, and determined the presence of root filling extrusion and voids independently; they were blinded regarding the obturation technique used. The presence of root filling extrusion was also assessed by inspecting the root apex after obturation. The data were analysed using logistic regression models.Results A total of 300 root fillings were performed and 291 were included for analysis. Most of the root fillings were placed within 0.5 mm of the working length (80%, n = 233); only 20% (n = 58) were placed >0.5 mm beyond the working length. The odds of prevalence of extrusion >0.5 mm were significantly reduced by approximately 50% when cold lateral condensation (OR = 0.50; 95% CI = 0.26, 0.99; P = 0.04) or customization of master gutta‐percha cone (OR = 0.55; 95% CI = 0.30, 0.99; P = 0.04) was used. One operator produced 2.5 times more extruded root fillings than the other operators (OR = 2.50; 95% CI = 1.31, 4.78; P = 0.006). Other factors, such as root canal curvature and length, apical size of the prepared canal, as well as the operator's preferred obturation technique, were shown to have no significant influence on the prevalence of extrusion.Conclusions The prevalence of extrusion was significantly lower when cold lateral condensation and customization of the master cone were used. The ‘operator’ emerged as a significant factor affecting the prevalence of root filling extrusion.