Original scientific paper
Influence of Different Etching Times on Dentin Surface Morphology
Davor Brajdić
Ozren Mika Krznarić
Zoran Azinović
Darko Macan
Marijan Baranović
Abstract
The aim of this study is to investigate the influence of different etching times on demineralized dentin surface morphology
using scanning electron microscopy and qualitative line microanalysis of chemical structure. Two sample
groups, consisting of 30 first premolar teeth in each group, were established. Teeth were cut at the half-distance between
the enamel-dentin junction and the pulp. The first group of specimens was etched for 10 seconds and the second group
for 30 seconds. 37% ortophosphoric acid was used. SEM (scanning electron microscopy) was utilized to observe the following
parameters: number and diameter of dentinal tubules, dentinal and intertubular dentinal surface percentage, appearance
of the dentin surface porous zone containing smear layer and demineralized residual collagen particles with
dentin demineralization products in acid globules, and dissolved peritubular dentin cuff. After calculating measurements
of central tendency (X,C, Mo, SD), Kolmogorov-Smirnov and Student t-test were performed to confirm the quantitative
results, and the c²-test was run to produce qualitative data. In contrast to the 10-second etching time, the increased
etching time of 30 seconds resulted in the following findings: (1) an increased number of dentinal tubules (p<0.05), (2)
an increase in dentinal tubule diameter (p<0.05), (3) an increase in dentinal tubule surface percentage (p<0.001), (4) a
decrease in intertubular dentinal surface percentage (p<0.001), (5) appearance of dentin surface porous zone containing
smear layer and demineralized residual collagen particles with dentin demineralization products in acid globules (p<
0.001), and (6) completely dissolved peritubular dentin cuff (p<0.001). Therefore, different etching times using the same
phosphoric acid concentration result in different morphological changes in demineralized dentin surface. Moreover,
based on a comparison with current studies, prolonged etching time causes morphological changes to dentin surface.
Such changes, have, in turn, negative effects on the dentin hybridization process.
Keywords
dentin adhesives; dentin surface morphology; dentin hybridization; dentinal tubule diameter; etching time; ortophosphoric acid; scanning electron microscopy
Hrčak ID:
27046
URI
Publication date:
2.9.2008.
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