Sure no problem at all. Basically, when we do aligners we are doing a digital scan of your teeth so if you have existing restoration, we are scanning your teeth according to the shape of the restoration, so it should not be an issue at all.
In fact, it is easier for my restorative dentist to fix maybe tooth decay and things like that, during the treatment, in the case where you develop tooth decay or something because there is nothing joining your teeth together so they can easily perform any restoration during the course of treatment with aligners.