Influence of buffering effects of dentifrices and fluoride gels on abrasion on eroded dentine.
OBJECTIVE
Evaluation of abrasion resistance of eroded and non-eroded dentine brushed with experimental dentifrices and gels of varying buffering capacities.


METHODS
One hundred and twenty human dentine specimens were distributed among six groups (A-F) according to the different buffering capacities of experimental toothpastes and gels. The dentifrices (pH: 4.5) and gels (pH: 4.5) differed in fluoride content, RDA-value and buffer capacity (given as mg KOH needed for neutralisation): (A) 0.125%F, RDA: 77, 6mg KOH; (B) 0.125%F, RDA: 125, 24mg KOH; (C) 0.125%F, RDA: 129, 12mg KOH; (D) 0%F, RDA: 81, 1.55mg KOH; (E) 1.25%F, RDA: 21, 8.5mg KOH; (F) 0.125%F, RDA: 7, 3.11mg KOH. Ten specimens were cycled through three alternating demineralisations (1% citric acid, 5min) and remineralisations (artificial saliva, 1min) including brushing abrasion in an automatic brushing machine (2 x 2000 strokes). Ten samples of each group were not eroded, but only brushed.


RESULTS
After three cycles, loss of dentine was determined by profilometry (mean +/- S.D. [microm]). Eroded samples: (A) 37.12+/-4.95; (B) 48.67+/-4.77; (C) 39.88+/-3.76; (D) 32.92+/-2.67; (E) 3.65+/-1.35; (F) 6.47+/-1.31. Uneroded samples: (A) 30.78+/-6.47; (B) 37.84+/-7.75; (C) 30.07+/-3.05; (D) 26.93+/-2.30; (E) 1.76+/-0.94; (F) 0.51+/-0.18. Analysis of variance revealed significantly higher abrasion values for the eroded compared to the non-eroded samples (P<or=0.05). Dentifrices with same pH-value, fluoride content and similar RDA-values but a higher buffering capacity exhibited significantly more abrasion than toothpastes with lower buffering capacity. Highly-concentrated fluoride gel with higher buffering capacity lead to less abrasion values compared to the gel with low fluoride concentration and low buffering capacity.


CONCLUSIONS
Toothbrushing abrasion behaviour of eroded dentine may be influenced by the fluoride content, RDA-value and buffering capacity of the applied dentifrice or gel.
Department of Operative and Preventive Dentistry and Periodontology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany. annette.wiegand@med.uni-goettingen.de
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Wiegand
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Wolmershäuser
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Hellwig
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Attin
D002021:Buffers; D003802:Dentifrices / Q000494:pharmacology*; D003804:Dentin / Q000502:physiology*; D005459:Fluorides / Q000494:pharmacology*; D005782:Gels; D006801:Humans; D008964:Molar, Third; D014072:Tooth Abrasion / Q000503:physiopathology*; D014074:Tooth Calcification; D014077:Tooth Erosion / Q000503:physiopathology*; D014089:Tooth Remineralization
D002021:Buffers; D003802:Dentifrices; D005782:Gels; D005459:Fluorides