A Study On The Effects Of NDGA-modified Etchant Upon The Resistance To Enzymatic Degradation Of Dentin Collagen And Its Mechanical Property

Objectives: To evaluate the effects of NDGA-modified etchant on the resistance to enzymatic degradation of dentin collagen and its mechanical property.Methods: Human third molars were collected from the out-patient department of maxillofacial surgery,Tongji hospital,and then processed into dentin slabs of certain size.Samples were randomly divided into groups,and treated with NDGA-modified etchant,PA-containing etchant,DMSO-containing 10% phosphoric acid and 10% phosphoric acid,respectively.After the demineralization procedure,a type-Ⅰ collagenase solution was applied to degrade the samples.The degradation rate(DR),hydroxyproline(Hyp)release and modulus of elasticity(MOE)of dentin collagen under different treatment was measured and calculated.Data were statistically analyzed by ANOVA and Bonferroni test at a 95% confidence interval.Results: When dentin slabs were treated with NDGA-modified etchant,the treatment significantly(P<0.001)decreased the DR and Hyp release.The MOE of NDGA-modified etchant-treated specimens were not significantly different from those of control specimens.However,after 12 hours of degradation,the decrease of MOE in NDGA groups was significantly lower than that of a control group(P<0.001).Conclusion: The application of 0.5% or 1% NDGA-modified etchant could significantly increase the resistance of dentin collagen to the collagenolytic activities induced by type-Ⅰ collagenase.Moreover,it could effectively enhance the stability of dentin collagen’s mechanical property.