Protection of short-time enamel erosion by different tetrafluoride compounds.
OBJECTIVE
This in vitro study aimed to analyse the protective effect of differently concentrated titanium (TiF(4)), zirconium (ZrF(4)) and hafnium (HfF(4)) tetrafluoride on enamel erosion.


METHODS
Polished enamel surfaces of 36 bovine crowns were covered with tape leaving 4 enamel windows each 3mm in diameter exposed. The crowns were randomly assigned to six groups (each n=6) and pretreated with 4% TiF(4), 10% TiF(4), 4% ZrF(4), 10% ZrF(4), 4% HfF(4) or 10% HfF(4) for 4 min (first window), 10 min (second window) or 15 min (third window). The fourth window of each crown was not pretreated and served as control. Erosion was performed stepwise with 1% HCl (pH 2) in five consecutive intervals of each 15 s (total 75 s). Enamel dissolution was quantified by colorimetric determination of phosphate release into the acid. For each tooth, cumulative phosphate loss of enamel pretreated with one of the tetrafluoride compounds was calculated as percentage of the respective control and statistically analysed using two-way ANOVA.


RESULTS
Enamel erosion was significantly reduced by TiF(4), ZrF(4) and HfF(4) application. Cumulative phosphate loss (mean % of control, 75s erosion) after 4-15 min application was significantly lower for 4% ZrF(4) (7-11%), 10% ZrF(4) (2-6%), 4% HfF(4) (11-9%) and 10% HfF(4) (12-16%) compared to 4% TiF(4) (42-27%) and 10% TiF(4) (54-33%). Only for 4% and 10% TiF(4), phosphate loss decreased with increasing duration of application, but also increased with increasing acid intervals.


CONCLUSIONS
TiF(4), ZrF(4) and HfF(4) might protect enamel against short-time erosion, but protection was more enhanced by ZrF(4) and HfF(4) compared to TiF(4) application overtime.
Wiegand
Annette
A
Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zürich, Plattenstrasse 11, 8032 Zürich, Switzerland. annette.wiegand@zzmk.uzh.ch
Laabs
Kolja Alexander
KA
Gressmann
Grit
G
Roos
Malgorzata
M
Magalhães
Ana Carolina
AC
Attin
Thomas
T
D000818:Animals; D002327:Cariostatic Agents / Q000627:therapeutic use*; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects*; D003747:Dental Enamel Solubility / Q000187:drug effects*; D005459:Fluorides / Q000008:administration & dosage*; D006851:Hydrochloric Acid; D010865:Pilot Projects; D019228:Tooth Crown; D014077:Tooth Erosion / Q000139:chemically induced / Q000517:prevention & control*; D016896:Treatment Outcome
D002327:Cariostatic Agents; D005459:Fluorides; D006851:Hydrochloric Acid