Treatment planning of every patient requires detailed assessment of the facial profile and features, together with the intra-oral features, such as the amount of crowding present, and if the front teeth are flared forward, etc. Together with analysis of your X-rays, your orthodontist will advise you what they feel is the treatment plan that will give you the most ideal result.
Overlapping of the teeth (crowding) and flaring of the teeth forward means that there is a lack of space, which is why extractions of teeth to provide space have been proposed. The spaces from the extractions of teeth would also be used to upright the teeth and bring them inwards to improve the protrusive lip profile.
What is important is also what your concerns are - if you would like to improve your protrusive mouth profile, extractions would be advised as space is required to move the teeth inwards and allow the lips to move back. If you are willing to accept your current lip profile, there are ways to distalize (move back) the back teeth create some space to align the teeth and correct the crowding. However, this treatment plan would be best carried out with all wisdom teeth removed, and there is a limit to how much space can be created with this method.
I have also noticed that your lower right lateral incisor and canine are fused together. This does not create much issue, the upper and lower teeth may not fit perfectly as there will be a space imbalance however, this is rarely visible as it is at the sides and your teeth can still bite well together. Your orthodontist can advise you better on this.
With regards to loss of gums, braces treatment with extractions does not routinely result in loss of gums during treatment, however if there are receeded gums prior to treatment (such as the recession present on your crooked upper right first premolar), this will maintain. Overlapping teeth may sometimes result in black triangles. When teeth are straight, there is a triangular shaped gum tissue (papilla) present between the teeth. Overlapping teeth do not have space for this papilla and aligning these teeth will show a black triangle of the papilla that wasn't there to begin with.
Do share your concerns with your orthodontist so that he or she can explain to you his or her reasons for their treatment plan. Different clinicians can have different treatment plans and yet all achieve a good result for the patient, there are many ways to treat a case.
Hope this helps!
Dr Geraldine Lee