etching
To ensure that the layer adheres properly, the dentist or dental hygienist roughens the grooves and pits in the enamel with an acidic liquid or gel. That's called etching.
To rinse
After a short exposure time, the dentist or dental hygienist rinses away the acidic liquid or gel with water. This is done with an air/water syringe. The water is sucked up with a saliva ejector.
sealing
Now the dentist or dental hygienist can apply the layer to the tooth. The applied material penetrates deep into the bottom of the grooves and pits.
curing
Then the material has to harden. This can be done automatically or with a lamp that gives blue light. If the dentist or dental hygienist uses a lamp, he sometimes protects the eyes with an orange screen. Finally, the dentist or dental hygienist checks whether the layer is firmly attached.