I Have Gap Between the Left Side Lower Molar Teeth's. The Crown Part is Joined but the Lower Portion Has Some Gap?

If the gap is small, it often becomes a source of food and plaque being pushed down around the gums (called a food impaction site), which initiates or exacerbates any gum problems.  The answer would be to have a new crown made that fills the space. 

If the space is wide enough so that it can be easily cleaned with flossing, brushing, water pik, or other dental aids, then you may be able to maintain healthy gums with just very frequent and diligent teeth cleaning with those dental aids.  However, some patients having less than great dexterity will have difficulty keeping those spaces clean and healthy.  Then again, may be better to close the spacing with crowns or possibly a bridge.

If your breath problem is due to the plaque, either of these treatments may help your breath.  However, many times breath odor comes from plaque and bacteria on the back of the tongue, from gastric reflux or diet.  The latter two you may want to discuss with your physician.

If the margin of the tooth below that crown is adjusted ,on a way where the profile layout merges functional ,yes it can close that gap ,and you will have a solution for this problem easily, it takes 2 appointments.and its  a simple proceedure,