Yes, it can be corrected with Invisalign. Make sure you are seeing an orthodontic specialist who went to an accredited orthodontic program and has treated many of these types of cases, and it can be done.
Yes, if made correctly and worn as instructed by your orthodontist, retainers will prevent your teeth from further shifting. Remember, retainers are for "retaining", and not necessarily for "moving" teeth. They should do a good job keeping them in their current position, but if you want to move them back to their original position, you should investigate treatment using braces or Invisalign with your orthodontist.
Your orthodontist can prescribe the teeth to move in any way they want. It's the orthodontist who makes the treatment plan, not Invisalign. I slow down the movements on all of my Invisalign cases, but double the number of trays. I find this to be more efficient and better for the patient. Follow instructions your orthodontist gave you. They attended an additional 2 or 3 years of education after dental school just to study how teeth move.
To get the best results from Invisalign it is advisable to use the necessary attachments. Most patients get used to them very quickly, and your health care provider can make them as comfortable and invisible as possible. For my patients who refuse to have attachments put on (which is very rare), I tell them that we will not get the full correction as we would using the attachments. The alternative is traditional braces (or clear aesthetic braces, or lingual braces that go behind the teeth). None of these alternatives are as comfortable as Invisalign aligners with attachments.
If your doctor scheduled you to change your aligners today, then I would change them today. If you have been wearing the aligners as prescribed, the blue dots usually fade, but not always. It doesn't hurt to wear the aligners extra days, but probably not necessary if you have been following your doctors orders.
