The bone in the front of your mouth is extremely thin. So, losing a front tooth usually makes the bone melt away rather quickly. This will cause the bone and gums to cave in; and, the defect that is visible when smiling tends to make people self-conscious about their appearance. When front teeth are replaced by a traditional bridge, the teeth on either side should look natural. But, as time goes by, the gums and bone above the false tooth collapse and leave the false tooth hanging and looking fake. As the bone deteriorates above the bridge, a visible gap often appears between the gums and the bridge. This problem is more obvious when more than one tooth is lost in the front of the mouth.