I feel a gap at the back of my dental bridge and the gum line, can infection get in between?

Gaps can be irritating which causes food trap. If you do have a gap you need constantly clean in between to get rid of food, bacteria, and prevent halitosis. It is best to see your dentist and address the issue, and see if the gap can be eliminated via restoration or a new bridge.

The space you are reffering to is not susseptible to infection, however this may be a food trap and can accelerate decay on the adjacent teeth.  Make sure the area is well flossed all the time.  There techniques where by the pontic (false tooth) is enbedded in the gum, this is called an ovate pontic.  Eliminates the space but makes it more difficult to clean underneath.  Beneficial in the front of the mouth not so much in the back. 

Hope this helps and enjoy the ability to chew again.

The gap between the back of your bridge and your gum line is fine to have.  In fact, this design is purposely used to promote the health of your gums.  Because of this gap, it is easier to brush and clean underneath your bridge.  This design is not likely to cause infection, as the area can be easily cleaned.  Enjoy your new bridge.  All the best, Dr. Elizabeth Jahanian