Why can't you just place a filling doc?

I get this question all the time. Why can't I place a filling and recommend a crown or onlay? Great question. Fillings are great. That is whenever appropriate. In fact recent studies show that composite (tooth colored fillings) actually can strengthen integrity of your crown if you have decay, broken silver filling, etc. I am not saying however, if you have fine intact tooth structure, that removal of that sound tooth structure and placing a filling would strengthen your tooth. That is false' your healthy intact tooth structure is the strongest thing.

In any case, the reason for progression of a filling to a crown or onlay involves typically the size of the cavity (or need for replacement of a filling) and extension of the issue requiring work. Your teeth have points called cusps and deeper parts called grooves. Think of a mountain: the peak is the cusp and the valley is the groove. If whatever work you require involves extension into the cusps, the typically a crown or onlay is recommended. This is the most typical reason for recommendation of a crown/onlay vs filling. Why can't I just place a filling to replace these cusps? Because placement of those is very unpredictable and likely lead to premature failure and cracking of your tooth (which may possibly involve the nerve and require additional procedures like a root canal). Those cusps are what your teeth uses to chew and break apart food. They receive a lot of pressure and force. A filling material has insufficient strength to act as a cusp, hence the need for something stronger and more durable like a crown or onlay.