OR32 - Bioactivity of Novel Copper Nanostructured Gels Based on Two-step Synthesis Assessed in Multispecies Biofilm-Contaminated Root Canals In Vivo.

Abstract:
The persistence of infection in root canals affects the outcomes of endodontic procedures. This study assessed the bioactivity of copper nanostructured gel on multispecies-contaminated root canals in vivo using an intra-osseous implantation model. Thirty human, 3-mm-long root segments with a 1.2-mm canal lumen were divided into 5 groups (n=6): group 1, canals contaminated with a multispecies biofilm (MSB) and disinfected with sonic activation of ethylene-diamine-tetraacetic acid and sodium hypochlorite (UA/EDTA/NaOCl) and with copper nanostructured gel (1.0mM); group 2, canals contaminated with MSB and disinfected with UA/EDTA/NaOCl; group 3, canals contaminated with MSB and disinfected with UA/EDTA/NaOCl and calcium hydroxide; group 4, canals contaminated with MSB; group 5, canals not contaminated. Specimens were implanted into the tibia of male Sprague Dawley rats, block dissected after 4 weeks, and the canal content was evaluated histologically and immunohistochemically. The ingrown neotissue interface (50μ) with dentin was characterized for fibroblasts, osteoclasts, inflammatory markers, dentin resorption, mineralization, and angiogenesis and dichotomized as type 1 (no inflammation and resorption, indicative of multispecies biofilm disinfection) or type 2 (inflammation and resorption). The frequency of the observed parameters was analyzed using Fisher’s exact test (p < .05). The outcome was categorized as type 1 in groups 1 and 5, type 2 in group 4, and mixed type 1 and 2 in groups 2 and 3. The outcomes in groups 1 and 5 (p > .05) differed from other groups (p < .05). Disinfection of multispecies-contaminated root canals with a copper nano-gel in vivo supported the absence of signs of inflammation or resorption, suggestive of effective disinfection of dentin-bound multispecies biofilm.