Smaller cavity = less destruction of the tooth = smaller filling. Smaller fillings typically last longer and do not weaken the tooth as much as larger fillings. In addition, the smaller the cavity, the less likely the tooth will be sensitive following placing a filling and the less likely the tooth will need root canal treatment.
How Cavities Form
Cavities form when acid erodes a hole through the hard outer shell of enamel that covers a tooth. This exposes the softer dentin layer to decay. The old method for detecting decay was to use an instrument called an explorer with a very tiny pointed tip to find holes in the enamel. The problem is that holes in the enamel can be smaller than the tip of the explorer, so this method is not as sensitive as fluorescent cavity detection. Because dentin decays much faster than enamel, by the time the hole in the enamel can be found with the explorer, the dentin underneath may be severely decayed.
With the advances in fluorescence technology, we can now shine a light on the surface of the tooth and metabolic products specific to cavity-causing bacteria glow, allowing earlier detection. Dr. Gray still uses explorers, but now he has far more sensitive diagnostic equipment available as well!