S E Langhorst1, J N R O'Donnell, D Skrtic. 1. Paffenbarger Research Center, American Dental Association Foundation, National Institute of Standards and Technology, 100 Bureau Drive Stop 8546, Gaithersburg, MD 20899-8546, USA.
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 120microm 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 1mm 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 degrees 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.
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 120microm 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 1mm 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 degrees 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.
Authors: Lei Cheng; Michael D Weir; Hockin H K Xu; Joseph M Antonucci; Alison M Kraigsley; Nancy J Lin; Sheng Lin-Gibson; Xuedong Zhou Journal: Dent Mater Date: 2012-02-02 Impact factor: 5.304
Authors: Jing Xia; Jing Zheng; Diaodiao Huang; Z Ryan Tian; Lei Chen; Zhongrong Zhou; Peter S Ungar; Linmao Qian Journal: Proc Natl Acad Sci U S A Date: 2015-08-03 Impact factor: 11.205
Authors: Lei Cheng; Michael D Weir; Hockin H K Xu; Alison M Kraigsley; Nancy J Lin; Sheng Lin-Gibson; Xuedong Zhou Journal: Dent Mater Date: 2012-02-06 Impact factor: 5.304
Authors: Chen Chen; Michael D Weir; Lei Cheng; Nancy J Lin; Sheng Lin-Gibson; Laurence C Chow; Xuedong Zhou; Hockin H K Xu Journal: Dent Mater Date: 2014-06-18 Impact factor: 5.304