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Published on: July 10, 2014
A bioactive radiopaque infiltrant for managing early enamel carious lesions - an in-vitro study
Mahmoud Abdelgawad Hasan1, Amina Khatoon2, Stellios Arseniyadis2
1Centre for Oral Bioengineering, Institute of Dentistry, Faculty of Medicine and Dentistry, Queen Mary University of London, UK; Paediatric and Preventive Dentistry Department, Faculty of Dentistry, Mansoura University, Egypt.
Objectives:
To develop a bioactive radiopaque infiltrant (BRI), compare its radiopacity and degree of conversion (DC%) to ICON, and evaluate its ion release, infiltration into artificial caries, and acid-resistant bioactivity.
Methods:
BRI was prepared with 30% non-silanated fluoride-containing bioactive glass (FBG) and 70% radiopaque resin infiltrant (RI) comprising 2,2,2-tribromoethyl methacrylate, TEGDMA, and UDMA. Degree of conversion and radiopacity were measured via FTIR and digital radiography, with ICON as control. Artificial enamel lesions (n=10) were infiltrated with BRI (without HCl pre-conditioning) and divided into pH 4 and pH 7 immersion groups (n=5 each). Bioactivity was assessed by ISE, ICP-OES, XRD, and SEM. Penetration depth and mineral changes were tracked using X-ray microtomography (XMT) at baseline, 8 weeks, and 23 weeks.
Results:
BRI showed significantly higher DC (84.9%) than ICON (74%) and radiopacity of 3.2 mm Al equivalent (vs. 2.0 mm for enamel). Sustained Ca²⁺ and F⁻ release over 23 weeks was greater at pH 4 than pH 7. XRD and SEM confirmed hydroxyapatite formation on infiltrated surfaces, while XMT revealed radiopacity increases consistent with progressive mineral deposition.
Conclusion:
A 30% FBG loading maintained both resin penetrability and sustained bioactivity.
Clinical Significance:
This novel BRI enables radiographic monitoring of proximal early caries while providing acid-buffering protection, offering a potential advance over conventional non-bioactive infiltrants.
