I’m the same as the original poster. I’m 37 and pretty much every back tooth has restoration in it, I have quite a few root fillings, crowns and one implant. It costs me a fortune to maintain. I’ve never been a fizzy drinker, don’t smoke, rarely drink alcohol (apart from uni years), and I have a healthy diet, and every other part of my body health is great (e.g weight, good hair, skin etc). However there’s no issues with my front teeth, not a single filling, so I look like I have healthy teeth they are white.
These are the things that I believe have contributed to all my dental problems:
-my mum was slightly hippie’ish and was very fearful of chemicals in the 80s particularly where dental education was concerned so we were always taught to rinse the toothpaste out of our mouths, I didn’t learn the correct way until early/mid 20s, she also refused the fissure sealants that most children have painted on their back teeth as a preventative as she didn’t want chemicals added to our bodies
-80s and early 90s dentistry was bad and there were massive financial incentives to perform lots of fillings, so many of my fillings were done when I was quite young which leaves a lifetime of maintenance. I doubt I needed them.
-I definitely should have been given a brace and had teeth extracted, to reduce overcrowding, I need to floss a lot, if you have a small natural space between each tooth your saliva can wash between easily which protects your teeth. I don’t have any space.
-I also learnt that my biting ridges are quite big, whereas some peoples back teeth are more flatter, so again more areas for food to trap.
-I reckon I have bad saliva

-although my diet is healthy it does include lots of fresh food (acids and sugars, lots of tomato based sauces etc) A dentist’s version of what’s healthy to eat is very very different from anyone concerned about body nutrition.
-I’ve had two children which gives you extra bad saliva during hormone changes.
-I definitely think I’ve been exploited by many dentists, I pay for white fillings, so as soon as they see I’ve paid for an implant and have white composite fillings they see

(no different to how some tradesmen judge your house/car before quoting for a job)
I’ve only come to these answers after finding some really good dentists and hygienists, who don’t come out with the usual guilt trip ‘you must brush badly, eat lots of sugar, drink fizzy drinks’ crap. I always say, well why are my front teeth in such good condition, and I’ve always been a petite size 6/8 so I hardly look like an over-eater.
I now have a really good private dentist who is focused on preserving the life of teeth, he sometimes does fissure seals when an NHS dentist would be pushing a white filling. I have B U P A 20 which refunds most of my fees for white repairs, check ups and twice yearly hygienist.
I hate my teeth condition and it causes a lot of stress.