The measurement of enamel wear by four toothpastes.
OBJECTIVE
To determine the enamel abrasivity of three whitening toothpastes and a silica toothpaste and to measure the brushing forces used.


METHODS
Polished human enamel blocks were indented with a Knoop diamond and attached to dentures of adult volunteers. The blocks were brushed ex vivo, twice per day with either a whitening toothpaste containing Perlite (White System), a commercial whitening toothpaste (A and B) or a silica toothpaste. After four and twelve-weeks, one block per subject was removed and the Knoop indent remeasured. From the changes in the indent length, the amount of enamel wear was calculated.


RESULTS
The mean enamel wear (sd) for White System, silica toothpaste, whitening toothpaste A and B after four-weeks was 0.14 (0.15), 0.09 (0.16), 0.14 (0.12) and 0.89 (0.93) and after twelve-weeks was 0.24 (0.21), 0.37 (0.73), 0.36 (0.52) and 1.04 (0.98) microm respectively. After four-weeks, the differences in enamel wear between whitening toothpaste B and all other toothpastes were of statistical significance (p < 0.003), but not after twelve-weeks. The mean ex vivo normal brushing force (sd) was 2.67 (1.33) N.


CONCLUSIONS
All three whitening toothpastes did not give significantly more enamel wear than a silica toothpaste after twelve-weeks in situ with ex vivo brushing.
Joiner
A
A
Unilever Oral Care, Bebington, Wirral, UK. Andrew.Joiner@Unilever.com
Pickles
M J
MJ
Lynch
S
S
Cox
T F
TF
D000368:Aged; D000537:Aluminum Oxide / Q000009:adverse effects; D003743:Dental Enamel; D003799:Dental Stress Analysis; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012822:Silicon Dioxide / Q000009:adverse effects; D014072:Tooth Abrasion / Q000209:etiology*; D014100:Toothpastes / Q000009:adverse effects*
D014100:Toothpastes; C003076:Perlite; D012822:Silicon Dioxide; D000537:Aluminum Oxide