ABSTRACT
Abstract The aim of this study was to obtain ionic quantification in periradicular medium after diffusion tests of the solution used inside root canals during the electrochemical dissolution of endodontic file fragments and the NiTi-containing dissolution product via an apical foramen. Thirty single-rooted extracted human teeth had root canals prepared and were attached to Eppendorf tubes filled with sterile saline. The samples were divided into 3 groups (n = 10) according to the solution used inside the root canal during the diffusion tests: Group 1: [NaF 12 g/L + NaCl 1 g/L]; Group 2: [NaF 12 g/L + NaCl 1 g/L + NiTi 0.50 g/L]; Group 3: [NaF 6 g/L + NaCl 0.5 g/L + NiTi 0.25 g/L]. The sample in each Eppendorf tube was then analyzed to assay the ionic quantification in periradicular medium. The groups were compared in relation to ionic quantifications (Kruskal-Wallis and Dunn's tests, p ≤ 0.05). Group 2 showed significantly higher F-, Ni and Ti quantities than groups 1 and 3 (p < 0.05). Group 3 showed significantly higher Ti and Ni quantities than group 1, where no measurable quantities of Ti and Ni were observed (p < 0.05). The conclusions were that a 50% dilution of the NiTi-containing dissolution product resulted in significantly lower F-, Ni and Ti quantities compared to the undiluted product. The quantifications observed here suggest that irrigation is recommendable during the electrochemical dissolution process to reduce the resultant ion concentrations in both the root canal and the periradicular medium.
ABSTRACT
This study evaluates the antimicrobial susceptibility and composition of subgingival biofilms in generalized aggressive periodontitis (GAP) patients treated using mechanical/antimicrobial therapies, including chlorhexidine (CHX), amoxicillin (AMX) and metronidazole (MET). GAP patients allocated to the placebo (C, n = 15) or test group (T, n = 16) received full-mouth disinfection with CHX, scaling and root planning, and systemic AMX (500 mg)/MET (250 mg) or placebos. Subgingival plaque samples were obtained at baseline, 3, 6, 9 and 12 months post-therapy from 3–4 periodontal pockets, and the samples were pooled and cultivated under anaerobic conditions. The minimum inhibitory concentrations (MICs) of AMX, MET and CHX were assessed using the microdilution method. Bacterial species present in the cultivated biofilm were identified by checkerboard DNA-DNA hybridization. At baseline, no differences in the MICs between groups were observed for the 3 antimicrobials. In the T group, significant increases in the MICs of CHX (p < 0.05) and AMX (p < 0.01) were detected during the first 3 months; however, the MIC of MET decreased at 12 months (p < 0.05). For several species, the MICs significantly changed over time in both groups, i.e., Streptococci MICs tended to increase, while for several periodontal pathogens, the MICs diminished. A transitory increase in the MIC of the subgingival biofilm to AMX and CHX was observed in GAP patients treated using enhanced mechanical therapy with topical CHX and systemic AMX/MET. Both protocols presented limited effects on the cultivable subgingival microbiota.