What is a tooth coloured filling?

Jane is at the dental office for a six months dental cleaning appointment. 
While checking her teeth, the dentist told her she is getting a cavity and it needs to be filled. 
The dentist kindly explained that cavity is like a hole on the tooth. There is decayed tooth structure in the hole. The filling will be a tooth colored material. 

So, How the dental filling is done?

The cavity is small and not going deep to touch the nerve. Then a regular filling can be done. 

first the dentist will use a drill to remove the decayed tooth structure. that means the hole is going to be a little bigger. They need to prepare the cavity in a way that the filling material will stick to the tooth. 

Once the tooth is prepared, they etch the tooth surface using 37 percent Phosphoric acid. It is blue coloured and comes in a plastic syringe usually. The etch will roughen the tooth surface so that the filling will stick to the tooth very nicely.

Etch will be washed with water and then the tooth will be dried using air. Then cotton rolls will be placed on the sides of the tooth to prevent saliva getting on the tooth.

Next step is the application of bonding. Bonding agent is a liquid plastic. This liquid will flow into the etched surface nicely. Then the dentist use a blue colored light to harden the bond so that it will be locked on the tooth surface. Then a composite material is added on top it to give tooth its necessary shape.

Each layer of composite material is hardened using curing light . Once the filling is done, then the height of the filling adjusted so that it feels normal when you are biting. 

That is how a simple dental composite filling is done.