Penetration of chlorhexidine coating into tooth enamel: A surface analytical study.
Chlorhexidine has proved an efficient antibacterial agent and has been used successfully to prevent new carious lesions in the teeth of adults and children. The substantivity of chlorhexidine has not been identified with any precision, but is certainly not of short duration. In this work, surface analytical techniques have been applied to study the chemical composition, distribution, and penetration of an applied liquid coating containing chlorhexidine onto tooth enamel in order to ascertain mechanisms by which chlorhexidine keeps its long term substantivity. Several hypotheses have been put forward with regard to its substantivity, including concepts of chlorhexidine remaining as a reservoir upon application either in the epithelial surfaces, the tooth surface, or the biofilm. Alternatively, it has been proposed the teeth themselves act as the reservoir. To study this, a chlorhexidine containing liquid coating was applied to the surface of teeth. These were subsequently transversely cross-sectioned. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were performed on both surfaces to ascertain chemical composition and distribution of the applied coating. It was found that it formed a coating layer of about 25 μm thick. High spatial ToF-SIMS images showed little evidence of substantial diffusion of chlorhexidine into the enamel, either from the surface or via the enamel lamellae.
Ontario Centre for the Characterisation of Advanced Materials, Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario M5S 3E5, Canada.
Rana N S
RN
Sodhi
Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G 1G6, Canada.
John
J
Symington
D000891:Anti-Infective Agents, Local / Q000378:metabolism*; D002710:Chlorhexidine / Q000378:metabolism*; D003743:Dental Enamel / Q000737:chemistry* / Q000187:drug effects*; D006801:Humans; D009067:Mouthwashes / Q000378:metabolism*; D056951:Photoelectron Spectroscopy; D018629:Spectrometry, Mass, Secondary Ion; D014070:Tooth / Q000737:chemistry* / Q000187:drug effects*
D000891:Anti-Infective Agents, Local; D009067:Mouthwashes; D002710:Chlorhexidine