Effect of brushing on dentin permeability of dentin discs

Objective: To evaluate the effect of simulated brushing with two different toothpastes on dentin permeability after previous treatment with a desensitizing gel (DG). Methods: Forty eight dentin discs 1.00±0.08mm in thickness, obtained from human molars, were divided into 6 groups: G1-brushing with deionized water (DW); G2-brushing with Colgate^® toothpaste (Col); G3-brushing with Sensodyne^® toothpaste (Sen); G4-DG+brushing with DW; G5-DG+brushing with Col; G6-DG+brushing with Sen. The methodology used for the measurement of hydraulic conductance of dentin (Lp) was based on the model suggested by Pashley, Stewart and Galloway, 1984. The simulated brushing test was conducted using a mechanical device, with controlled pressure and time. ANOVA and Student-Newman-Keuls test (p<0.05) were applied to the percentage of Lp to detect intra and inter-groups differences (p<0.05). Results:

	G1	G2	G3	G4	G5	G6
Max	100	100	100	100	100	100
Min	43,3 a	41,9 a	11,6 a	23,1 a	13,0 a	06,1 a
DG				08,0 a	06,5 a	17,9 b
DW	145,9 b			65,5 b
Col		19,9 b			08,1 a
Sen			15,3 a			08,1 a

Intragroup % Lp – different letters in same column = statistical difference.

	G1	G2	G3	G4	G5	G6
Gel				15,0	6,4	11,8
Treatments	102,6 a	22,0 b	3,7 b	48,1 c	4,8 b	2,0 b

Intergroups % Lp – different letters = statistical difference.

Conclusions: The effect of mechanical brushing, by itself, can contribute to the increasing of the permeability of dentin. The association of DG and tooth pastes with occlusive properties, such as Sensodyne^® can contribute to significantly reduce the hydraulic conductance of dentin and, therefore, decrease dentin hypersensitivity.