This thread is of interest to me because at 74, and after a life of having full chewing capacity on both sides, I have at last lost a tooth creating a gap on the lower right. I am finding this surprisingly irritating and can see that I will, once another tooth is lost, want to have the gap(s) filled in - but not with conventional false teeth. Implants are of some interest just now and I have made initial enquiries.
I am told that if you have sufficient bone mass available at the site (I have plenty all round) then it is fairly straight forward but if not additional bone may need to be grafted in. I know someone who had a few teeth (molars) implanted and swears by them (about 10 years younger than I and healthy). Another (just a couple of years younger than I but not as fit) has had the preliminary work done for a few teeth - one tooth cannot be implanted because the bone graft did not take.
I am told by one dentist that even with less than ideal bone mass and grafting not an option then a lot can still be done but that it is then (obviously) more of a challenge in every sense.
Clearly, if money is tight then implants are not to be considered, certainly not if it is going to seriously cramp the finances - unless they solve an even worse problem. As a ball park figure, £1000 per tooth seems to be an indicator but much depends on who does the work and where and the average cost per tooth can be significantly less than that.
Undoubtedly, things have not always gone perfectly for both dentist and/or patient but my impression is that overall the concept is well established and the results are as reliable as one can generally expect with any intervention to/in the body. The teeth are expected to last a lifetime and if one breaks it is as easy to replace it as replacing a crown on a natural tooth (create a new one and glue it on).