Closing teeth gap about 5-6mm. What is my best option? (Photo)

From past experience in dealing with cases similar to what you present with,  I would say correcting the space would involve the following:1.  Having a board certified orthodontist place braces and attempt to divide the space (5-6mm) between your front two teeth into smaller equal spaces between the front eight teeth.  This will be a slow process, but important to do before proceeding to step two.2. Have a cosmetic dentist place porcelain veneers over the front eight teeth to close the smaller spaces created during orthodontics.  This will make the teeth proportionate in size and allow you to choose a nice, natural color. 3.  You look as though you are a tongue thruster.  This means that when you swallow you push your tongue against the inside of your upper teeth.  This causes a space between your top and bottom teeth.  Please ask your orthodontist about this and what can be done to prevent your teeth from relapsing following treatment.  Good luck.  With patience you can have a very desirable result at the end of treatment.  

Planning is the key to good results.  Prior to making changes a diagnostic wax up allows you to see final position and size of teeth.  Minimal restoration will probably be 4 teeth but could be 8 teeth.  The closing of the space could proceed while you gradually remove the bonding to prevent having huge space.  The spaces are redistributed so you can have a new smile with all the teeth propotional in size.  Excess space can be moved back where it is not an esthetic problem.When finished you want a natural smile.

A very good question.  I am unable to see the surrounding teeth in your photo.  One thing in your question stood out. You said "I decided to have bonding on only 2 teeth".in my practice, I would never allow the patient to make choices that look "bad". Whomever put 3 front teeth in the front wasn't thinking cosmetically at all.  Never an option. There are a number of ways to close spaces.  But I as a cosmetic dentist, will only present options to a patient, that are reasonable, will appear attractive, and on the scale of what appears naturallally pleasing to the eye,  and what does not.

HI There!  You can go to 5 different dentists and get 5 different answers.  Amazing no?  We all have a different approach to what works.  In my office we treat most gaps with Invisalign.  Why?  Because we are good at Invisalign and I get the results my patients want. And because first and foremost for any smile re-design is getting the teeth in the right place.  This makes a difference for your long term health, and long term function of your teeth.  Invisalign does that.  Even before starting Invisalign, I would first make your two front teeth the same size and shape.  Then I would set up your Invisalign therapy to close that gap while correcting any other mis-alignment.  I would also recommend whitening in the Invisalign trays.  So when you are done you will walk away with the smile of you dreams!  Good luck!