Preliminary in vitro evaluation of Carisolv as a root canal irrigant

AIM: To test the null hypothesis that Carisolv is no better than PBS in removing organic debris from uninstrumented root canals. METHODOLOGY: The pulps of two uniform groups of 36 immature, sheep mandibular incisors were grossly removed with barbed broaches immediately prior to the study. Roots in group 1 were irrigated with phosphate buffered saline (PBS), strong sodium hypochlorite (4.5%) or Carisolv without ultrasonic agitation, whilst in group 2 the same irrigants were activated with ultrasound. Canal walls were exposed to irrigants for 10, 20 or 30 min at 37 degree C. In group 2, ultrasound was applied for 30 s at 2, 5 and 7 min within each 10 min incubation period. After washing irrigants free and immersion in fixative, all teeth were split longitudinally, critical point dried and sputter coated for SEM analysis. SEM photomicrographs were recorded of representative areas in the coronal, middle and apical canal thirds and debris scored by a single assessor against a five-point scale. Intraobserver reliability was assessed by Cohens kappa scores and debris scores analysed by the non-parametric Kruskal-Wallis test at P < 0.05. RESULTS: Sodium hypochlorite was significantly better than Carisolv and PBS in cleaning root canals (P < 0.0001), whether or not ultrasound was applied. Carisolv was shown to clean canals better than PBS, again whether or not ultrasound was applied (P = 0.01). Both incubation time and ultrasound enhanced the action of Carisolv (P < 0.001) whilst the activity of PBS was not significantly improved by exposure time or the application of ultrasound. Kappa scores of 0.90-0.95 indicated excellent consistency in debris scoring. CONCLUSIONS: Within the limitations of this preliminary study (i). Carisolv cleaned root canals better than PBS and shows promise as an adjunct to root canal preparation; (ii). the action of Carisolv was enhanced by incubation times beyond 20 min whether or not ultrasound was applied; (iii). sodium hypochlorite solution remains the gold standard endodontic irrigant, provided that it is used with care and is contained in the canal system.