Gold crown and resin duration and dental implants

Nine years ago, I received resin and gold fillings for my teeth. I was told there is a replacement period, but dental treatments are expensive and not painful, so I keep postponing it. I am curious about when I should replace the resin and gold fillings!

And seven years ago, I finished root canal treatment on a molar and left the medication inside, but I experienced severe pain and visited the hospital. They said there was no problem, but when the medication was removed, the tooth stopped hurting. I was scared and left it untreated. Now, the bone structure remains, but the middle is hollowed out. I think I need an implant, and I am curious about how much it would cost and whether I need to replace the implant.

I really think being healthy is the best thingㅠㅠ There is pain in treatment and it is expensive 🥺