What does sealant restorations mean?

Sealants are used to protect healthy teeth that have a high potential for decay. Most often, these are the molars with deep grooves. A PRR, preventive resin restoration, is a type of filling that is placed when a cavity has begun and is infiltrating the grooves in the chewing surface of the tooth

Efficiency is an action of doing something. for example when you take a test. good efficiency means you did well but bad effeciency or no effiency means you did bad.