You can not reuse the implant that failed. You will need a new implant placed. If your ridge can accommodate a wider diameter implant, you may be able to have a new implant placed immediately. If not, you'll most likely need to have the site grafted, and a new implant placed in a few months.
When there is adequate keratinized tissue, an implant can be placed flapless with no stitches, and when an implant is placed immediately with tooth extraction no stitches are required.
A partial denture is a like a can opener which will cause you to lose more teeth over time. Save up for the implants. In the mean time, have your dentist make you a upper and lower clear retainer like an Invisalign retainer which will keep your teeth from shifting.
It is common to see bone loss after teeth extraction. The severity of bone loss depends on how long you have been missing your teeth, and wearing a denture usually excellerates the bone loss. In most cases, there is still enough bone in the front of your lower jaw to place dental implants. In those cases where there is not enough bone for dental implants, your options may be: bone graft, distraction osteogenesis, or find a dentist who is familiar with a multi-modal approach to implant dentistry and can place a ramus frame or subperiosteal implant that requires no bone grafting.
Get your teeth straightened with braces or Invisalign first. As far as the color of your teeth and white spots, try bleaching your teeth to whiten and if the white spots are still noticeable, have your dentist use a very conservative white spot removal gel. After this treatment is completed, you may not even need veneers. It's best to stick to conservative, minimally invasive treatment, because once your teeth are prepared for veneers, you are in for a life time of dentistry.
