Effect of Disinfection Protocols on Bacterial Reduction in Mandibular Molars.

OBJECTIVE: Evaluate the bacterial reduction effect of disinfection protocols used in lower molars infected by Enterococcus faecalis. METHODS: Eighty extracted lower molars were prepared and inoculated with E. faecalis for 2 months. The teeth were then distributed into 2 control groups (n = 4) and 4 experimental groups (n = 18) in function of the disinfection protocol utilized: G1. WaveOne Gold (WOG), passive ultrasonic irrigation (PUI) and Ultracal; G2. WOG, PUI and calcium hydroxide (CH); G3. WOG, XP-Endo Finisher (XPF) and Ultracal; G4. WOG, XPF and CH. Bacteriological samples were collected previously (S1), after preparation (S2), final agitation (S3) and intracanal dressing (S4). Microbial growth was assessed according to culture turbidity and UV spectrophotometry. Statistical analyses used the Friedman test for paired samples and Kruskal-Wallis test for non-paired data (p<0.05). RESULTS: No protocol eliminated E. faecalis effectively. The S2, S3 and S4 samples were statistically different from the S1 samples in G1, G2, G3 and G4 (p<0.05). Statistical differences were observed in bacterial reduction between G1 and G2 and G1 and G3 after the intracanal medicament (S4) (p<0.05). CONCLUSION: The WOG + PUI + CH disinfection protocol showed higher percentages of bacterial reduction.

Influence of Chitosan 0.2% in Various Final Cleaning Methods on the Bond Strength of Fiberglass Post to Intrarradicular Dentin.

The purpose of this study was to analyze the influence of Chitosan 0.2% in various final cleaning methods on the bond strength of fiberglass post (FP) to intrarradicular dentin. Ninety bovine incisors were sectioned to obtain root remnants measuring 18 mm in length. The roots were divided: G1: EDTA 17%; G2: EDTA 17% + PUI; G3: EDTA 17% + EA; G4: EDTA 17% + XPF; G5: Chitosan 2%; G6: Chitosan 2% + PUI; G7: Chitosan 2% + EA; G8: Chitosan 2% +XPF. After carrying out the cleaning methods, the posts were installed, and the root was cleaved to generate two disks from each root third. Bond strength values (MPa) obtained from the micro push-out test data were assessed by using Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests for multiple comparisons (α = 5%). Differences were observed in the cervical third between G1 and G8 (p = 0.038), G4 and G8 (p = 0.003), G6 and G8 (p = 0.049), and Control and G8 (p = 0.019). The final cleaning method influenced the adhesion strength of cemented FP to intrarradicular dentin. Chitosan 0.2% + XPF positively influenced adhesion strength, with the highest values in the cervical third.