Molars fell out, what can cause this to happen?

Probably has gum desease. It eats the bone and eventually teeth wilk loosen and come out. She needs to be checked by a dentist. Gum desease can cause other problems.

Old age and poor hygiene in her earlier years.

Teeth are held on by ligaments. Contrary to what people envision, it's not bone growing out of another bone. It's a separate bone in a little socket held on by ligaments. Think of it as a ball being taped into a cup. When the ligaments wear out, it falls out.

My MIL was 92 when she lost a front tooth. A year later, she lost two molars. I accompanied her to the dentist each time. Her dentist advised me it was simply old age and not uncommon to have teeth rot at that age.

It's probably nothing serious with your MIL, but I would definitely follow up with a dentist appointment with x-rays. JoAnn29 is right: gum disease and poor dental hygiene can cause other problems.

Best of luck.

Dad is losing his teeth, has been since about age 86. Unfortunately his are breaking off at the gums and he did have some abscesses. He had to go to the dentist to have the roots removed and it was a painful experience. Now as his teeth break he is refusing to go back to the dentist.

But he is 90 now and does not seem to care that he is snaggle toothed. He eats soft foods and still smiles showing his missing teeth.

See a dentist not a physician. They know next to nothing about dental/ oral health. Gum disease or technically known as periodontal disease will cause tooth loss. This is brought upon by poor oral hygiene, bacteria and inflammation that results in the gradual loss of supporting ligaments and bones. I’m a retired dental hygienist who taught in the periodontics department of a university dental program. Please have an oral evaluation done if she is able to submit to it.

Dental hygiene is another ADL that people have problems with.
If she has been in assisted living have they been helping her with oral care?
When was the last time she saw a dentist?
At one point in my Husbands journey with dementia he became non compliant with the dentist. It was a tough decision to let that go. I brushed his teeth but the teeth that broke I could not do anything about. If he were to see a dentist he would have had anesthesia and I was not going to do that. If he had dental work they would have had to pull teeth and I was not going to try to care for him with a mouth full of open sores. Dealing with the possibility of dry sockets, infections, more pain and return visits I just could not put him through that. So bit by bit his teeth broke down. He was not chewing a lot by then most all of the food was soft and thickened so chewing was minimal.
So personal opinion I would not stress bout the teeth. It would probably be more trouble to get her to the dentist and sedate her to pull any loose ones.
As long as there are no sharp bits of tooth left she will probably not even notice.

robinr,

Thank you for your reply to my earlier post. In the community Dad was living in the only option was a dentist. It is a rural community with a visiting dentist a couple times a month. She is very competent.

A general anesthetic for oral surgery is not possible for Dad. He had 6 extractions and it was the weeks of healing afterwards that he did not like as well as the initial extractions.

He is well aware that not having his teeth attended to will cause other problems, but it is his choice at this point.

My dad had the most perfect teeth.  So white and straight.  When he started to reach his late 80's he started to not take proper care of his hygene and his teeth just started to fall out.  He'd be eating and he'd spit out a tooth.  He never had any pain at all.  Never wanted to see a dentist about it.  Never wanted dentures.   When he died at 92 last year, he had about 3 teeth left.   We all just assumed it was old age and gum disease.   I can still remember his smile.  : (

My Mom 92 is in nursing home they have a mobile dentist come in every 6 months do xrays & Look at teeth. They can only do extractions. What else could you do for someone if they are bedridden & can't walk. So going to a regular dentist she couldn't get in the chair even if we got transport there. She has cavities under her bridge & Another bad area.