Short Communication: In vitro evaluation of the abrasiveness of acidic dentifrices.
OBJECTIVE
This in vitro study evaluated the abrasiveness of acidic fluoride (F) dentifrices with different F concentrations on bovine enamel.


METHODS
Enamel blocks (4.0 x 4.0 mm2, n=120) were selected according to their surface microhardness and divided into 12 groups. Slurries of dentifrices were used containing 0 (placebo), 275, 412, 550 and 1,100 ppm F (pH 4.5 or 7.0), as well as testing two commercial dentifrices (Crest, positive control, 1,100 ppm F and Colgate Baby, 500 ppm F). Enamel blocks were partially protected with an adhesive tape (control area) and then brushed by an automated toothbrushing machine (16,000 strokes). During this process, 0.4 ml of the slurries were injected every 2 mins on the enamel blocks. After toothbrushing, enamel wear was determined by profilometry.


METHODS
Results were analyzed by ANOVA and Tukey's test (p<0.05).


RESULTS
The mean values for pH in the suspensions during treatment were 6.93, 4.32, 7.56 and 8.19 for neutral experimental dentifrices, acidic experimental dentifrices, Crest and Colgate baby, respectively. The abrasiveness of the acidic dentifrices was similar (p<0.05) to the neutral ones, whereas commercial dentifrices yielded lower abrasion (p<0.05).


CONCLUSIONS
It was concluded that a reduction of the pH of dentifrices does not increase their abrasiveness.
Araçatuba Dental School, São Paulo State University and Bauru Dental School, University of São Paulo, Brazil.
K M
KM
Alves
J P
JP
Pessan
M A
MA
Buzalaf
A C
AC
Delbem
D000149:Acidulated Phosphate Fluoride / Q000737:chemistry / Q000627:therapeutic use*; D000818:Animals; D002327:Cariostatic Agents / Q000737:chemistry / Q000627:therapeutic use*; D002417:Cattle; D002626:Chemistry, Pharmaceutical; D003743:Dental Enamel / Q000473:pathology; D003802:Dentifrices / Q000737:chemistry / Q000627:therapeutic use*; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D010919:Placebos; D011897:Random Allocation; D012824:Silicic Acid; D012822:Silicon Dioxide / Q000737:chemistry / Q000627:therapeutic use; D012969:Sodium Fluoride / Q000737:chemistry / Q000627:therapeutic use; D014072:Tooth Abrasion / Q000209:etiology*; D014099:Toothbrushing / Q000295:instrumentation; D014100:Toothpastes / Q000737:chemistry / Q000627:therapeutic use
D002327:Cariostatic Agents; D003802:Dentifrices; D010919:Placebos; D014100:Toothpastes; C546060:hydrated silica gel-based toothpaste; D012824:Silicic Acid; D000149:Acidulated Phosphate Fluoride; D012822:Silicon Dioxide; D012969:Sodium Fluoride