Can you give me more info on fissure sealants at the dentist?

Deep Sealants: When teeth have very deeps grooves and dramatic anatomy, there can be fissures in the teeth where the bacteria can occupy. To seal these fissures, the dentist opens and cleans them with a micro drill, and then flows a sealer material into the opened fissures. Once the sealer is cured, the fissures are filled. A regular sealant is just a flowable layer cured on the top surface of the teeth.

Like "caulk"...: Sealants to teeth are like 'caulk' around the edges of a bathtub. After the tooth is cleaned and slightly 'etched' a fluid composite material is flowed onto the grooves/pits of your teeth to keep food and liquids out(to prevent cavities.

Mainly for molars: Sealants are a flow able resin coating that seal the grooves on mainly permeant molars. But can be applied to any teeth.

Less Cavities: Sealants are ideally used to flow into deep natural tooth grooves (after a thorough debridement and proper preparation). The reason is that the groove may be so narrow that the toothbrush cannot get to the base of the groove to keep it clean = it would decay (cavity). By having the sealant flow into the base of this groove, it reconfigures the groove so that a brush can keep it clean.