Ethylenediaminetetraacetic acid and citric acid solutions for smear layer removal in primary tooth root canals.

PURPOSE: The purpose of this in vitro study was to evaluate, via scanning electron microscopy, the micromorphology of the dentine walls of primary anterior teeth with focus on the presence of the smear layer after endodontic debridement and final irrigation with different systems. METHODS: Thirty primary maxillary anterior teeth were assigned to 3 groups according to the final irrigant solution. Group 1 received 1% sodium hypochlorite; Group 2 received 17% EDTA followed by 1% sodium hypochlorite; and Group 3 received 6% citric acid followed by 1% sodium hypochlorite. The canals were debrided using 1% sodium hypochlorite to a size 30 file, and the final irrigation was performed with one of the 3 irrigants as assigned. The teeth were prepared for examination of the canal walls by electron microscopy for the presence or absence of the smear layer. RESULTS: Group 1 had significantly higher scores for remaining smear layer than Groups 2 and 3 (P<.01), while Groups 2 and 3 presented similar smear layer score values. CONCLUSIONS: Sodium hypochlorite promoted the formation of a smear layer during shaping, and the use of EDTA and citric acid facilitated smear layer removal.

Dentin rehardening after indirect pulp treatment in primary teeth.

PURPOSE: The purpose of this study was to investigate dentin rehardening in the remaining carious dentin after indirect pulp treatment (IPT) using microhardness analysis after 37 to 71 months. METHODS: Eighteen teeth submitted to IPT and capped with calcium hydroxide (CH) or gutta-percha (GP) were evaluated (treated group). Ten sound molars and 10 molars with deep acute carious lesions were selected to serve as positive and negative control groups, respectively. In the treated group, restorations and pulp-capping materials were removed. In the positive control group, 3- to 4-mm deep cavities were prepared. In the negative control group, the carious tissue was removed. Microhardness analysis was performed at 10-, 35-, 60-, 85-, and 110-microm depths. Data were analyzed using 1-way analysis of variance (P<.05). RESULTS: Microhardness values for sound, carious, and treated groups at 10-, 35-, 60-, 85-, and 110-microm depths showed a statistically significant difference (P