In general, the larger the filling, the greater the chance of
breakdown.  Most of these teeth need crowns or onlays--restorations that
cover the chewing surfaces of the tooth.  The risk is fracture of the
tooth, likely leading to tooth loss.
    If a patient must delay definitive restoration of a tooth, use a
material (resin or amalgam) that will seal the crown of the tooth well.
 It is sometimes advisable to shorten the tooth slightly so that there
are smaller chewing forces on the tooth involved.

Steve

Depends on case
1- fracture is one risk
2- reinfection

There is questions what diagnosis you had. what kind of temporary dressing
is inside and outside the tooth

best regards kris Polanowski DDS