Effect of modified 5% sodium fluoride on the surface roughness and hardness of the enamel of primary incisors: An in vitro study

Abstract

Background: There has been interest over the past decade in the principle that additives that promote the formation of calcium hydroxyapatite can increase the efficacy of sodium fluoride varnishes (NaF). Aim: This study aimed to compare in vitro; the protective effect of a commercially available 5% NaF varnish with the protective effects of 5% NaF varnishes enhanced with functional tricalcium phosphate (fTCP) and amorphous calcium phosphate (ACP). Methodology: A total of 120 primary incisors were divided into four groups of 30 teeth. Group 1 comprised a control group that received no fluoride varnish, Group 2, teeth treated with 5% NaF varnish, Group 3, treated with 5% NaF enhanced with fTCP and Group 4, teeth treated with 5% NaF enhanced with ACP. Surface roughness before and after pH cycling was measured using a profilometer, whereas surface microhardness was measured after pH cycling. Results: Teeth in Group 4 (ACP) and Group 3 (fTCP) showed significantly higher surface microhardness values than the other groups, but there existed a large variation in the range of values obtained. No Significant differences were observed in the change in surface roughness among all groups. Conclusion: The large variation seen in the microhardness values suggest that the effects of the addition of ACP or FTCP to 5% NaF varnish may not be predictable in primary teeth.

Keywords

• Amorphous calcium phosphate
• fluoride varnishes
• pH cycling
• sodium fluoride
• surface roughness
• tricalcium phosphate