Unless one is experiencing enough sensitivity that they canu2019t eat or drink, or if the edge of the tooth is so sharp that it is cutting the tongue or gum, I would leave it alone until a dentist can replace the filling.Otherwise, if you live in an area where a temporary dental filling (such as DenTek or DenTemp) is not available, and the tooth is extremely sensitive or sharp, you could do one of two things to plug the hole. Try to find a soft wax such as beeswax and place it in the cavity where the filling once was. Warm it with your fingers until it is quite malleable. The cavity should be dry and clean ( the process of frying and cleaning the hole most likely will be quite painful) so that the wax will adhere to the surfaces of the tooth. The other product you could use is sugar free chewing gum, although one person who answered your question warned against using gum. Do not sleep with the wax or gum plug in place because it might get dislodged and cause choking. And it is possible it will become dislodged while chewing.