Why can’t I just have a filling?  We are often asked this question when we are recommending treatment for a cavity.  Sometimes you can have just a filling but that depends on how much remaining tooth structure there is.  Think of it this way.  If there is a lot of tooth left than the tooth is strong and the cavity is small.  In this situation a filling is all that is needed.  A filling means there is tooth all around the cavity and the area can be filled in.  Now consider if about ½ of the tooth is involved in the cavity.  In this situation there is not enough tooth left to hold the filling in.  Once this occurs there are only two ways to restore the tooth.  As long as about ½ of the tooth is left, than a restoration called an onlay can be used to restore the tooth.  An onlay is fabricated in the dental laboratory out of a strong, solid block of material.  Once this solid piece is bonded or cemented to the tooth it is very strong and will restore the tooth to function.  The final option is a crown.  In this case even more of the tooth is involved and requires even more re-enforcement to restore the tooth.  A crown looks like a new tooth and is placed on top of the remaining base of your tooth.  Once cemented or bonded this too is a very strong, predictable way to restore a tooth to function.  If we recommend more than a filling it is because long term one of the other options is the appropriate option.