The pdf linked in other threads shows that the teeth have a fabric cord running through the middle of them. Then each tooth is surrounded by about 18 tiny stitches.
Yes, there are many places in the US that are currently having infrastructure crises due to too little density. There might need to be infrastructure upgrades as neighborhoods become denser, but over the long run, the infrastructure will be much more sustainable because the cost per user will be significantly lower.
For an in depth talk about the affect of directing your salary to charity check out the following Tech Talk by Toby Ord: "How Many Lives Can You Save? -- Taking Charity Seriously"
They talk about using the metric of "how many lives can be saved" with your cash.
ABSTRACT
People admire doctors and rescue workers and marvel at the possibility of saving someone's life -- something that few of us would ever achieve. And yet at the same time, we routinely hear that for a small sum of money we could save someone's life in a developing country and this scarcely impacts our behaviour. There is an important disconnect between these two attitudes and it has serious moral implications. I will speak about the evidence which shows that we really can make a tremendous difference by giving, and then explore the moral case for giving much more than we typically do. I will then look at the great disparity in effectiveness between different charities and show how choosing where to give can be even more important than the decision to give in the first place.
https://imgur.com/a/o1jxAuS