First of all, let’s establish what a cavity is. Basically, a cavity is the loss of some part of the tooth to the process of decay brought about by the action of acids which demineralize the crystalline structure of the tooth.
However, before we start to speak of a cavity, there are early signs of that decay which can be detected which only affect the outer covering of the tooth - the tooth enamel. While still confined within that layer, the structure can be re-strengthened externally by means of fluorides or any substance which promotes a re-mineralization of the weakened structure.
When left unnoticed and unaddressed, that decay will then extend beyond that outer layer and into the inner layer of the tooth which makes up the bulk of the tooth which is called the dentin.
It is then when that process “branches out” and becomes unreachable by external means (owing to the microscopic structure of the dentin) that the decay spreads deeper into the tooth and leads to a softening of that layer.
At some point, the outer covering of the tooth loses support and collapses. That is what most patients consider to be a cavity and this is when they will seek out the dentist to restore the broken part of the tooth.
In some cases, however, the decay may go so deep into the tooth without the outer layer being broken until the pain is felt. That pain is a signal that the pulp (‘nerve”) of the tooth is reached and, in that case, a root canal treatment would be necessary.
So, to answer the question, the best way to deal with early signs of dental decay is to actually have your dentist detect them.
If you visit your dentist regularly every 6 months, dental decay can be detected in its early stages and treated before it spreads into the deeper layers. Early cavities can be detected before any pain is felt and treated by conservative and minimally invasive restorations on which modern day dentistry revolves around today.
Remember, the smaller the filling, the more durable it is and the stronger the restored tooth will be.