SEALABILITY OF THE TRIFECTA(TM) TECHNIQUE IN THE PRESENCE OR ABSENCE OF A SMEAR LAYER

The aim of this in vitro study was to assess the sealability of a rece ntly introduced thermoplasticized gutta-percha technique (Trifecta, Hy genic Corp., OH, USA) in the presence or absence of a smear layer. A t otal of 100 teeth with single straight root canals were included in th e study. The teeth were decoronated and the canals prepared with a mod ified double-flared technique under constant irrigation with 2.5% sodi um hypochlorite solution. The apical matrix was prepared to size 40 an d apical patency subsequently confirmed with a size 10 file. Four teet h were discarded for technical reasons and the remaining 96 allocated randomly into two groups of 44 teeth and a group of eight teeth which acted as controls, Canals in group 1 were obturated randomly with eith er cold lateral condensation of gutta-percha or with the Trifecta tech nique, Canals in Group 2 were rinsed with 17% REDTA to remove the smea r layer and then obturated with lateral condensation or the Trifecta t echnique. All teeth were suspended in India ink for 9 days, deminerali zed, and rendered transparent prior to the assessment of apical linear dye penetration. Apical extrusion of sealer and gutta-percha occurred commonly but there was no significant difference between the four obt uration groups. However, overall, there was significantly more extrusi on of sealer with the Trifecta technique compared with lateral condens ation (P < 0.05). The majority of canals (79 out of 88) had no evidenc e of apical leakage and there was no significant difference between th e groups. The prevalence of sealer and gutta-percha penetration into t he dentinal tubules was significantly different between the four obtur ation techniques (P < 0.01) and significantly more common in the absen ce of the smear layer (P < 0.001). Under the conditions of this study, the Trifecta technique proved a satisfactory alternative to lateral c ondensation. Removal of the smear layer did not enhance sealability de spite increasing the proportion of specimens with dentinal penetration of sealer and gutta-percha.