# Etching time is more in primary teeth than permanent teeth due to:
A. Irregular placed enamel rods
B. Aprismatic enamel
C. More inorganic matrix
D. More amount of water
The correct answer is B. Aprismatic enamel.
Deciduous teeth have an outer layer of aprismatic or prismless enamel. They require a longer etching time. Earlier it was advocated 120s, but now reduced to 60 s and more recently to 30s for bonding of pit and fissure sealants and orthodontic brackets. A significant research in this field made it clear that very long etching periods did not improve the bond strengths of the currently available adhesives.
No comments:
Post a Comment
Add Your Comments or Feedback Here