I have a narrow buccal corridor, how can I fix it to a wide one without braces? (Photos)

I had my braces off the other day and I’m still unhappy with my smile. They are very straight, however, I hate how my back teeth disappear and I can only see a few teeth when I smile. I’d love to have a wider smile or a full set. My dentist said this wasn’t achieveable with braces as there wasn’t enough room in my mouth. What my options? Composite bonding, partial dentures or anything else? I would still be required to wear retainers due to having braces.