Operative dentistry

Is an infectious disease caused by bacteria mostly streptococcus mutant and lactobacilli. These bacteria when gets substrate i.e carbohydrate containing foods, release acids by metabolization of refined carbohydrates and acids starts dissolving calcified structures of tooth causing demineralization and when enough minerals gets dissolved the surface of tooth breaks down and produce cavitations.

Factors responsible for caries:

1. Bacterial plaque: plaque is soft, tenaciously attached material on the tooth surface consisting of bacteria and their end products. Once these bacteria adhere to tooth surface, they proliferate and spread laterally and form mat like covering over the tooth surface plaque becomes mature by colonization of sufficient amount of bacteria then these plaque bacteria rapidly metabolizes carbohydrate (sucrose), produces acids resulting in sudden drop of pH causing demineralization. Demineralization occurs at pH of 5.0 to 5.5.
   
2. Carbohydrate substrate.
   
3. Susceptible tooth sites.
   
4. Decrease salivary flow.
   

   Enamel caries:
   

   • Incipient caries:
     

   Incipient is initial carious lesion confined to enamel only, surface of the enamel is intact while minerals from subsurface gets dissolved, clinically it appears as smooth, chalky white in color when it is air dried only. This initial lesion may be reversed by remineralization.
   

   • Arrested caries:
     

   Carious lesion that becomes arrested because of remineralization effect, clinically it appears as intact but discolored usually brown, black in color and hard in texture. These arrested caries are more resistant to caries attack. They should not be restored unless they are esthetically demanding.
   

   

Pits and fissure caries on first molar

• Dentinal caries:

Caries progress much faster in dentin then enamel because dentin contains less minerals and possesses microscopic tubules that allows ingress of acid and egress of minerals. That’s why dentin caries has much less resistance to acid attack.

Pit and fissure caries extending into dentin

Proximal caries involving distal surface

Caries involving multiple tooth surfaces