Fluoride pit and fissure sealants belong to which
generation?
I
II
III
IV
TYPES OF PIT AND FISSURE SEALANTS
1. Based on curing method:
First generation:

Polymerized with ultraviolet light of 350 nm wavelength. 
Absorbs UV light excessively and prevents complete polymerization of the sealant. 
Light intensity varies from lamp to lamp.

Second generation:

Self-cured or chemically cured. 
Most of them were unfilled. 
Can be transparent, opaque or tinted. 
Filled show increased wear and abrasion resistance than unfilled.

Third generation - Visible light cured of 480-490 nm wavelength. 
Fourth generation - With addition of fluoride for added benefit.
Soben Peter
5th edition
Page no. 440