Effects of calcium phosphate lozenges on enamel lesions : an in vitro study

by Ng, Yuen-wai

Abstract (Summary)
(Uncorrected OCR) Abstract Abstract of thesis entitled Effects of calcium phosphate lozenges on enamel lesions: an in vitro study submitted by Ng Yuen Wai B.D.S. for the degree of Master of Dental Surgery at The University of Hong Kong November 2004 Despite recent declines, caries remains the most prevalent dental infectious disease with a giant unmet treatment need in many countries. This decrease is considered to be largely due to the widespread use of anticariogenic active ingredients. The first part of the thesis reviewed the active ingredients for caries preventive additives in candies and chewing gum. This included fluoride, chlorhexidine, xylitol, casein phosphopeptides amorphous calcium phosphate, carbamide and calcium carbonate. Furthermore, the review included the mechanism of action, side-effects and media for delivery of each of these agents. In conclusion, the mainstay of caries prevention and remineralization still revolves around fluoride. Use of chlorhexidine digluconate as an anticaries agent still remains controversial. Several studies have suggested the anticariogenic potential of xylitol and casein phosphopeptides amorphous calcium phosphate. Nevertheless, limited data are available on additives, such as carbamide Abstract (urea) and calcium carbonate which are currently used in only a limited range of sugar-free products in order to enhance their anticariogenic properties. The second part of the thesis addressed the caries preventive effects of calcium phosphate lozenges which, to date, have hardly been studied. Therefore, the purpose of this study was designed to evaluate and compare the de/remineralizing ability of a lozenge containing calcium phosphate with an identical lozenge without calcium phosphate using an in vitro pH cycling model. Thirty sound extracted third permanent molars were coated with acid resistant nail varnish, leaving a 1mm wide window prior to being placed in a demineralizing solution to produce artificial carious lesions in enamel. The teeth were subsequently cut longitudinally into 100-160 urn thick sections. The 27 specimens were randomly assigned into three groups, subjected to pH cycling for 10 days and exposed to the different lozenges. Tooth sections in Group A were exposed to a calcium carbonate and xylitol containing lozenge. Group B contained no active ingredient while those in Group C contained carbamide, dicalcium and xylitol. Polarizing light microscopy and microradiography were used to evaluate the lesions after they had been subjected to 10-days pH cycling. The lesion depth measurements showed that the lesions progressed by 16% in Group A, 55% in Group B and 23% in Group C. ANOVA revealed a significant difference between Group A and B (p< 0.01) and Group B and C (p< 0.05). However, no significant difference was found between Group A and C. Therefore, this study indicates that lozenges containing calcium carbonate and xylitol (Group A) and those with carbamide, dicalcium and xylitol (Group C) can reduced the extent of the demineralization process more than a lozenge with no active ingredient (Group B). ii
Bibliographical Information:


School:The University of Hong Kong

School Location:China - Hong Kong SAR

Source Type:Master's Thesis

Keywords:dental caries prevention calcium phosphate enamel


Date of Publication:01/01/2005

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