ABSTRACT: 0200

Stiffness of demineralized dentin is affected by tannic acid treatment

K.C. EMA¹, K.J. YOO¹, D. PASHLEY², and A.K.B. BEDRAN-RUSSO¹, ¹University of Illinois - Chicago, USA, ²Medical College of Georgia, Augusta, USA

Tannic acid is a collagen cross-linking agent that may affect the mechanical properties and stability of the dentin matrix. Objectives: To evaluate the effect of different concentrations of tannic acid and application time on the modulus of elasticity of demineralized dentin.

Methods: Twelve sound molars were sectioned into 0.5 mm thick fragments. The fragments were fully demineralized in 10% Phosphoric acid and divided into 3 groups (n=12): 1% Tannic Acid (1%TA), 10% Tannic Acid (10%TA), 20% Tannic Acid (20%TA). Specimens were immersed in their respective solution and tested at baseline, 10 min, 30 min, 1 hour, 2 hour, 24 hours and 48 hours. Specimens were subjected to 3 point bending forces at 3% strain. Statistical analysis was performed using two-way ANOVA and Fisher's PLSD test (p < 0.05).

Results: Modulus of elasticity values expressed in MPa [mean (SD)] are:

Treatment

Time

baseline

10 min

30 min

1 h

2 h

24 h

48 h

Pooled data

1%TA

6.53
(1.64)

26.32
(9.67)

48.32
(18.98)

66.79
(32.07)

90.06
(40.05)

159.76
(54.44)

192.18
(85.99)

84.28B
(34.69)

10%TA

5.97
(1.30)

47.15
(13.17)

70.12
(21.90)

89.70
(29.24)

109.92
(40.17)

156.89
(66.55)

159.98
(68.68)

91.39B
(34.43)

20%TA

6.65
(1.65)

63.69
(23.39)

98.00
(30.06)

124.70
(45.09)

144.99
(51.94)

182.31
(69.03)

174.55
(63.92)

113.55A
(40.72)

Pooled data

6.38f
(1.53)

45.72e
(15.41)

72.15d
(23.65)

93.73c
(35.47)

114.99b
(44.05)

166.32a
(63.34)

175.57a
(72.86)

* Upper and lower case letters indicate statistically significant differences on rows and columns respectively.

No statistically significant difference between the 2 factors (treatment vs. time p = 0.1454) evaluated were observed. The different times and concentrations significantly affected the values (p < 0.0001).

Conclusions: The use of TA affected the mechanical properties of demineralized dentin by increasing the stiffness. Increased mechanical properties of dentin matrix may be important during adhesive restorative procedures. Supported by NIH-NIDCR DE017740.

Seq #44 - Environmental Influences on Adhesive Bond Strength
1:30 PM-2:30 PM, Thursday, April 3, 2008
Hilton Anatole Hotel Trinity I - Exhibit Hall

Back to the Dental Materials 1: Adhesion - Bond Strength Testing and Mechanisms Program