Of the various types of teeth, the pre-molars and molars, being back teeth, are the hardest to brush-clean, especially their chewing surfaces. This is also due to the deep and narrow pits and fissures that can be found on their chewing surface. These pits and fissures are so deep and narrow that toothbrush bristles cannot enter and clean inside them.
Further, tooth decay in premolars and molars is a quicker process for another reason. It is due to the fact that the enamel layer over the pits and fissures on their chewing surface is much thinner than elsewhere on the surface of teeth.
The pits and fissures are therefore prime locations on premolars and molars for food and bacteria to collect inside them. Not only is it difficult for these locations to be brush cleaned, but the thinner enamel layer over them makes it much easier for acceleration of tooth decay and cavity formation at these locations.
Dentists prevent the collection of food and bacteria at these pits and fissures on the chewing surfaces of premolars and molars. They do so by painting a liquid layer of resin-like plastic sealant over them after cleaning these surfaces to the best possible extent.
The idea behind this is dual. One is to prevent the food and bacteria from collecting inside the pits and fissures. The other is to augment the thin enamel layer. Both of these are designed to prevent tooth decay at these prime locations.
Two ways of hardening the liquid layer of plastic on the surface are in practice. One uses special blue spectrum curing light to harden and bond the liquid layer on the chewing surfaces of premolars and molars. The other uses a special property of certain resin sealants to bond on to the chewing surfaces through chemical reaction.
Children, in whom premolars and molars have just erupted, form the best suitable candidates in the view of dentists to be treated with dental sealants. This is because, in comparison with adults, the pits and fissures on the chewing surfaces of their pre-molars and molars are yet to be adulterated by food and bacteria.
This does not mean that dental sealants cannot be used in the case of adults. They can be used in adults too. However, their effectiveness may be less as the pits and fissures on the chewing surfaces of their pre-molars and molars have already been adulterated by food and bacteria.
Therefore, the application of liquid plastic sealant in their case necessarily has to be performed after the pits and fissures are first cleaned in the clinic to the extent possible.
Dental sealants can be used on other type of teeth too. However, in them, optimal protection is already available through the thicker layer of enamel on their surface. Further, such deep and narrow pits and fissures are absent on incisors and canines. Therefore, dental sealants are not necessary to be used on incisors and canines of at least those people, whose incisors and canines are not infected by tooth decay. |