2 molars removed as a child now have sensitivity starting

[Joy-Marie]

Hi there, when I was in about grade 5 I had to of my molars removed, one on each side. I have forever had a space on each side. Now at age 48 I have begun to have sensitivity on the tooth of one side next to the space. Not the last molar and I never had wisdom teeth grow in. My dentist suggested implants but I was wondering other than a bridge that will be harmful to my existing teeth that are in perfect condition, is there another way to help with the sensitivity? I will begin to use a toothpaste for sensitive teeth but I am worried about long term, will the gum line keep shrinking if the space doesn't get filled?