Ideally, fillings would last forever! That of course is the ultimate aim, but realistically, the vast majority cannot last more than 20 years, without needing replacement.
These are the main factors determining how long a filling will last:
- Size of the filling. A small filling will last the longest.
- Dentist technique. A really skilled chef can make the most basic ingredients into a gourmet dish. Give this chef the best dental materials and equipment and it'll probably end up in your stomach instead of your tooth!
- Material. There are entire textbooks written about dental materials.. In my opinion, the best results will occur when the dentist uses the material that they can use to the full potential. I'll be honest, I have only done 3 amalgam fillings as a qualified dentist; if I placed one today, it would probably last shorter than a temporary filling material that I place.
- Your dental history. Unfortunately, if you have had many fillings in the past or needed frequent replacement, this trend is likely to continue. It may be that you are not looking after your teeth well enough, your teeth are weaker, your diet is poorer, your saliva is less protective, you have damaging habits... Could be many other things!
On average, a good filling should last at least 5 years in my opinion.