Comparison of conventional, rotary, and ultrasonic preparation, different final irrigation regimens, and 2 sealers in primary molar root canal therapy

Purpose: The aim of this study was to compare the shaping effectiveness rotary nickeltitanium (Profile .04 ISO), ultrasonic (K-Type/Satelec), and stainless-steel hand file (K-file/Maillefer) instrumentation and to assess tubular penetration of 2 gutta percha sealers (AH Plus and Sealite-Ultra) following 4 different final irrigation regimens in primary molar roots. Methods: Distal roots of extracted human primary second molars were prepared with 1 of the 3 instrumentation techniques. Direct digital radiographs were obtained on a custommade platform before and after instrumentations. The amount of dentin removal, canal transportation, centering of preparation, changes in root curvature and working length, and zip formation were evaluated using image analysis. Results: While no significant differences were found between the 3 preparation techniques in regards to dentin removal (P>.05), ultrasonic instrumentation significantly increased the incidence of zip formation (P<.05) and decreased working length (P<.05). Following final irrigation with 2.5% sodium hypochlorite (NaOCL), 10% ethylenediaminetetraacetic acid (EDTA), 17% EDTA, or distilled water (control), tubular penetration of the tested sealers were investigated under scanning electron microscope. Use of AH Plus after 17% EDTA irrigation exhibited the best tubular penetration. Conclusions: Root canal preparation with Profile .04 ISO nickel titanium instruments can be a viable alternative to manual instrumentation in primary teeth. When used as a gutta percha sealer, AH Plus exhibits good tubular penetration when 17% EDTA is used for final flush.