Microhardness recovery of demineralized enamel after treatment with fluoride gel or CPP-ACP paste applied topically or with dielectrophoresis.
OBJECTIVE
To evaluate the microhardness of demineralized enamel remineralized in saliva after applying 1.23% APF gel or CCP-ACP paste with dielectrophoresis (DEP) or diffusion for 3 minutes.


METHODS
In this laboratory study, 25 enamel blocks of bovine incisors were soaked in demineralizing solution (10 mM HCl pH 2.5) for 10 minutes and remineralized in saliva for 1 hour, after applying 1.23% APF gel or CPP-ACP paste without fluoride with dielectrophoresis or conventional topical application for 3 minutes. The mean and percentage changes of surface microhardness in pre-demineralization, post-demineralization and remineralization stages were measured in the five groups. The results of all five groups during the three stages were compared by ANOVA and paired t-tests (P = 0.05).


RESULTS
The average surface microhardness recovery of APF gel (12,300 ppm fluoride) applied with DEP was higher than APF gel applied topically, or CPP-ACP paste applied with DEP or topically, and water control (P < 0.05). The percentage of surface microhardness recovery for APF+DEP, APF+Diffusion, CPP-ACP+DEP, CPP-ACP+Diffusion, and water control were 88.17%, 13.62%, 7.14%, 5.45%, and 4.02%, respectively. Demineralization treatment decreased the surface microhardness of enamel in all groups and the surface microhardness recovery in the APF+DEP group was significant (P < 0.001). The only significant paired difference was between APF+DEP and all other groups. No other paired difference approached significance. Surface microhardness recovery of enamel with APF+DEP was 12 times or 1,200% greater than APF gel applied topically, and CPP-ACP paste either applied topically or with DEP in one 3-minute application.
Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis, TN 38163, USA. civanoff@uthsc.edu
Chris S
CS
Ivanoff
Timothy L
TL
Hottel
Franklin
F
Garcia-Godoy
D000149:Acidulated Phosphate Fluoride / Q000008:administration & dosage / Q000494:pharmacology*; D000287:Administration, Topical; D000818:Animals; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology*; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects* / Q000473:pathology; D004058:Diffusion; D004586:Electrophoresis; D005460:Fluorides, Topical / Q000494:pharmacology; D006244:Hardness; D008422:Materials Testing; D012463:Saliva / Q000737:chemistry; D013997:Time Factors; D017001:Tooth Demineralization / Q000473:pathology*; D014089:Tooth Remineralization
D002327:Cariostatic Agents; D002364:Caseins; D005460:Fluorides, Topical; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex; D000149:Acidulated Phosphate Fluoride