Related Experiment Video
Updated: Jan 9, 2026
Oral Biofilm Analysis of Palatal Expanders by Fluorescence In-Situ Hybridization and Confocal Laser Scanning Microscopy
Published on: October 20, 2011
ATR-FTIR and confocal microscopy evaluation of irrigation protocols: correlating dentin alteration and biofilm
Vanessa Abreu Sanches Marques Costa1, Rafaela Fernandes Zancan1, Talita Tartari1
1Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Al. Octávio Pinheiro Brizolla 9-75, Vila Universitária, Bauru, São Paulo, Brazil.
Objectives:
This study aimed to evaluate the effects of different irrigation protocols on the removal of mono- and multispecies biofilms, as well as on chemical alterations induced in superficial dentin.
Materials And Methods:
Specimens were divided into two groups according to the irrigating solution used: sodium hypochlorite (NaOCl 2.5%) or saline solution (SS 0.9%), and were subjected to agitation using either passive ultrasonic irrigation or EasyClean. The chemical composition of dentin discs was assessed by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), based on the Amide III/Phosphate and Carbonate/Phosphate ratios at three time points: baseline, after conventional irrigation, and after agitation. In parallel, E. faecalis, E. faecalis + S. oralis, and E. faecalis + C. albicans biofilms were grown on bovine dentin blocks and subjected to the same irrigation protocols. Cell viability was quantified by confocal laser scanning microscopy following Live/Dead staining. Data were analyzed using Kruskal-Wallis, Dunn, and Wilcoxon tests (α < 0.05).
Results:
The Amide III/Phosphate ratio was significantly reduced in the NaOCl groups after agitation (p < 0.05), while changes in the Carbonate/Phosphate ratio were observed only in the SS groups when compared to NaOCl (p < 0.05). From a microbiological perspective, both activation methods with NaOCl significantly reduced cell viability, particularly ultrasonic activation in monospecies biofilms and EasyClean in multispecies biofilms (p < 0.05).
Conclusion:
Based on the results and the methodology applied, it can be concluded that NaOCl activation with either ultrasonic irrigation or EasyClean is effective for disinfection, although it promotes chemical changes in dentin.
Clinical Relevance:
This study analyzes the impact of irrigation protocols on biofilm removal and dentin composition. NaOCl activation was effective in reducing microbial viability but promoted chemical changes in dentin, highlighting the need to balance disinfection and structural preservation in endodontic practice.
