Extract the one with the big filling and no partner above, fill the other.

make sure the dentist removes the periodontal ligament on the extracted tooth.

Rinse with salt water (lots of salt, I like kosher salt for that) after your extraction, starting about 8-10 hours after, swish very lighty the first few days. On the second or 3rd day and once a day for the next week, soak a cotton swab, q-tip, in hydrogen peroxide and place a couple drops of that directly on the extraction site. Rinse with salt water about 1 minute after and spit out.

I have normally real nice teeth too, real straight, everything. In my early twenties i had a dentist that even asked if he could use my x-rays for text book purposes, teeth so perfect and straight, except for the fillings done as kid, which over the years have ruined my teeth. then I met a dentist up here locally who started destroying them too... a real shame what dentists can do to your teeth.