In vitro remineralization of enamel by polymeric amorphous calcium phosphate composite: Quantitative microradiographic study☆
Abstract
Objective
This study explores the efficacy of an experimental orthodontic amorphous calcium phosphate (ACP) composite to remineralize in vitro subsurface enamel lesions microradiographically similar to those seen in early caries.
Methods
Lesions were artificially created in extracted human molars. Single tooth sections a minimum of 120
μm thick were cut and individually placed in holders exposing only the carious enamel surface. The exposed surfaces were either left untreated (control) or coated with a 1
mm thick layer of the experimental ACP composite (mass fraction 40% zirconia-hybridized ACP and 60% photo-activated resin), or a commercial fluoride-releasing orthodontic cement. The composite-coated sections were then photo-cured and microradiographic images were taken of all three groups of specimens before the treatment. Specimens were then cyclically immersed in demineralizing and remineralizing solutions for 1 month at 37
°C to simulate the pH changes occurring in the oral environment. Microradiographs of all specimens were taken before and after treatment.
Results
Quantitative digital image analysis of matched areas from the contact microradiographs taken before and after treatment indicated higher mineral recovery with ACP composites compared to the commercial orthodontic F-releasing cement (14.4% vs. 4.3%, respectively), while the control specimens showed an average of 55.4% further demineralization.
Significance
Experimental ACP composite efficiently established mineral ion transfer throughout the body of the lesions and restored the mineral lost due to acid attack. It can be considered a useful adjuvant for the control of caries in orthodontic applications.
Keywords: Amorphous calcium phosphate, Caries, Enamel, Polymeric composite, Remineralization
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☆ Certain commercial materials and equipment are identified in this work for adequate definition of the experimental procedures. In no instance does such identification imply recommendation or endorsement by the American Dental Association Foundation or the National Institute of Standards and Technology, or that the material and the equipment identified is necessarily the best available for the purpose.
PII: S0109-5641(09)00100-6
doi:10.1016/j.dental.2009.01.094
© 2009 Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.
