All on 4.The transition zone is visible. It is possible to improve it through better prosthetics? Is there any solution? (photo)

Thank you for sharing your experience. Upon an evaluation, I would recommend a CT scan is done to evaluate height of bone, and depending on bone availability, the implants would have to be removed. Significant bone reduction would have to take place and new implants would need to be placed in a much higher level so the gingival transition line would be positioned higher, therefore being hidden upon smiling. I would recommend that this is done under IV sedation (our office offers a variety of sedation techniques) to make your experience as pain-free as possible and comfortable for you.

Thank you for posting your question and photos.  Based on the information you have shared, it appears that you are correct in your assessment that the transition line is visible due to inadequate bone reduction.  Your "before" photos show that you have a very high smile line.  Cases such as yours require careful consideration, especially to avoid showing the transition line.  To avoid showing the transition line in cases such as yours with very high smile lines, significant bone reduction is often required (much more than the average case).  In order to reduce such a large amount of bone, a few things must be considered.  1) how much bone will be left once you reduce enough bone to avoid showing the smile line; 2) will this bone reduction put you into the sinus?  If so, it will need to be lifted during the bone reduction.
Personally, I would be inclined to remove the implants and start over (if you wanted an All-On-4 type of solution). 

My first question based on your "before" photo is "why did you have your teeth extracted and all on 4 done?"My second question is "did you go to a specialist(s) to have this done?"For the first question, I'm going to guess that your crowns may have been failing and redoing them was uncertain. I say this because it does not appear to me as though you lost your teeth to gum disease or bone loss. For the second question, I'm going to "bet the barn" that you did not go to a specialist for this. No specialist (periodontist/oral surgeon/ or Prosthodontist) would have allowed you to have All On 4 with a case of a gummy smile such as you have. Whoever did this unfortunately misdiagnosed your case and as a result your treatment went in an awkward direction. Please see a specialist either in Prague or another European major city centre (if at all possible) to asses where to go from here. Without X-rays, I could not possibly give you any advise and would. It be fair to you. If you resubmit your X-rays, I would definitely give you a better direction. I wish you well in your endeavours with this. I wish things didn't turn out like this for you.