Is the Percentage of Collagen in Coronal Dentin Related to Microtensile Strength? An In Vitro Study

ABSTRACT

Objective:  To compare the percentage of collagen in the coronary dentin of human teeth across sexes, ethnicities, and age groups, and to correlate this percentage with the microtensile bond strength (μTBS) of an adhesive system.

Material and Methods:  Fifty-one sound extracted molars were selected from patients of different sexes and ethnicities with age variation between 16 and 51 years. The crown was separated from the root. The dentin of the coronal part was restored with a hybrid composite resin block. After 24 hours of storage in distilled water at 37 °C, each specimen was sectioned perpendicular to the bonding interface area to obtain beams with a cross-sectional area of approximately 0.9 mm². The beams were submitted to μTBS test until failure. The μTBS was expressed in MPa. The root portion containing 1.0 mm of the crown was processed histologically to assess the percentage of collagen. The following statistical tests were used: Kolmogorov-Smirnov, Mann-Whitney, Student's "t" test, Kruskal-Wallis, ANOVA, and the Pearson and Spearman correlation tests.

Results:  No-white and female individuals had the highest percentage of collagen when compared to white and male individuals (p<0.0001). The age group between 44 and 51 years had the highest percentage of collagen (p=0.0013). There were no significant differences in relation to µTBS regarding ethnicity, sex, and percentage of collagen.

Conclusion:  The percentage of collagen in coronal dentin is higher in the group between 44 and 51 years, in females, and in non-white individuals, and is not related to the microtensile bond strength.

Keywords:
Dentin-Bonding Agents; Collagen; Dentin; Tensile Strength