Functional Tricalcium-Phosphate Influence on Reminerlization Process of Fluoridated Enamel Surface

Objectives: Recently manufacturers introduced fluoride varnishes with functional additives as TCP, induced deep in enamel surface aiming hydrolysis and calcium hydroxiapetite with polymorph tri-calcium phosphate formation; evidenced to improve enamel resistance to demineralization but little studies available regard whether such additives will enhance or hinder the original fluoride remineralization potentiality
Methods: 37 sound extracted permanent premolars (for orthodontics reason) crowns sectioned and divided mesiodistally into area-A received 5% sodium fluoride varnish with additive Tricalcium phosphate (3M ESPE Clinpro™ Seefeld; Germany), area-B was control without any coating and area-C received 5% sodium fluoride varnish without additive (Fluorproptector®–Ivoclar Vivadent; Leichtenstein) coating. Teeth submitted for 5 days pH-cycle regime (modified Featherstone et al.1986), blocks kept individually in demineralizing solution (2.0 mM calcium,2.0 mM phosphate,0.030 ppm F,in 75 mM acetate buffe,pH 4.3) for 3 h (20 ml per block) and in remineralizing solution (1.5 mM calcium, 0.9 mM phosphate, 150 mM of KCl, 0.050 ppm F in 20 mM cacodylic buffer, pH 7.4) for 20 h (10 ml per block). After each cycle, blocks were kept in artificial saliva solution. This cycle repeated daily and blocks remained in remineralizing solution for 2 days until analyses. Samples were dried and examined with EDAX Scanning Microscope (METEK. Mahwah, USA) 5 KV acceleration voltage at high vacuum and magnifications of 6000x
Results: One-way ANOVA showed a significant difference (p<0.05) with best results among FL+fTCP in remineralization efficiency (m=3.48 ±SD=0.426) followed by FL-fTCP (m=2.98 ±SD=0.419) and at last the control group (m=1.98 ±SD=0.410) typical SEM enamel presented 3 aspects 1)demineralized ‘‘keyhole’’rods' core with intact inter-rod areas 2)intact enamel rods and prismatic substances 3)reminerlization displayed as thick and more frequent lines with no evidence of porosities nor decalcification
Conclusions: Results suggest fTCP additive significantly improve remineralization capacity of fluoride preparations and the need for further clinical validation