Myasthenia Gravis

[george7222]

Hello All,

I'm trying to get some information out there into cyberspace. This is a problem which I cannot find documented anywhere - I'm hoping writing about it will encourage people to talk about it or investigate it.

I'm a 33 year old male, and I've had MG for 15 years. I have been on varying doses of Mestinon for all of that time, and I've been on azathioprine for 13 years. I did have plasmapheresis and Intragam earlier on, but not in the last ten years. I had a thymectomy for a thymoma at the start. On the bright side, I'm doing well. Really no problems except some ongoing mild facial weakness.

However! I'm here to write about teeth. Up until my diagnosis with MG I had absolutely no problems with my teeth - not a single filling. Probably over the last ten years it's become obvious that I've got serious trouble with erosion of the enamel on my teeth - I have still never had a filling. The enamel erosion has been on the biting surface of the bottom premolars and molars, the outer side (cheek side) of bottom premolars, the outer surface of the bottom canines, and the back of my top front two incisors. There has also been associated "chipping" of teeth. The premolars and molars on the upper level are not affected (don't know why). Things are starting to look a bit crappy in there. My dentist has covered up parts of the damage with various white substances, but it does worry me quite a bit.

My dentist suggested bulemic people sometimes get erosion due to stomach acid on the teeth (and I'm not into that). Also people with reflux can get some enamel damage from stomach acid (I'm not aware of any reflux problems). He also pointed the finger at acidic drinks, in particular Coca Cola.

I will freely admit there was a period where I drank a lot of Coke, from 2000 onwards, and this was when most of the damage became obvious. I essentially gave up Coke in 2004 due to concerns about my teeth and I now wouldn't drink it more than once a week. (I drink coffee instead)

I think it's true, however, that other people can get away with drinking a lot of Coke. My sister, for example, would on average drink 3 cans of coke a day, and she doesn't have any problems.

My theory (I have a scientific background) is that Mestinon causes alteration in the pH or buffering processes your mouth. I think it is very plausible - mestinon (as a side effect) acts on muscarinic receptors in the parasympathetic nervous system causing constriction of pupils, sweating, dilation of some blood vessels, and increased salivation. Conversely, patients on Mestinon will be aware that when their mestinon dose is wearing off, they start to feel "dry" - dry hands, dry mouth, dry eyes.
So it follows that if you drink a lot of coke when your mestinon has worn off, there's potential to damage to your teeth, because there isn't enough saliva around. (The same my be true of Too Much saliva, but I don't know how the biochemistry in our mouths works). Regardless, if you're taking mestinon, for the majority of the time you're going to have either too much or too little saliva in your mouth.

The closest condition I have found to this is Sjogren's syndrome, where people have decreased saliva and a dry mouth. I did find a report somewhere about chipping of teeth in patients with Sjogren's syndrome.

So in summary, if you're taking Mestinon, be careful about having acidic drinks - I think Coke is the main culprit. Hopefully someone will see this post and do some proper research in this area.

[amm34]

Interesting, as I am in medical school now and just finished dental school as well. I also take the meds you listed. Well, the pattern of enamel wear that you mention is most consistent with GERD (reflux)- vomiting typically affects the upper, front teeth, but GERD affects the lower back teeth to the greatest degree. Soda is very acidic, which is true, and if you let it pool in your mouth, in can cause more damage to the back teeth, but usually if you are just drinking it normally you would see an equal distribution or on the inner surfaces of your teeth. It is true that mestinon causes increased salivation, which is a good thing. If this were solely a ftn of dry mouth, you would have an increased rate of tooth decay (cavities), not so much erosion. The most likely mechanism I see would be that mestinon definitely increases acid production in the stomach due to its affect on Acetyl choline... the increased acid likely could lead to some type of reflux, esp at night when you are sleeping. It pools in the back of your mouth as you lay, hence affecting your lower molars and premolars. In fact, I have gotten numerous ulcers since taking mestinon. I now take omeprazole and wear a night guard on my teeth... Just something to consider....

[george7222]

I agree the Mestinon could increase stomach acid production, but I don't see how the Mestinon could cause reflux. Mestinon speeds up the whole gastrointestinal tract. If a patient already had reflux, I suppose mestinon might make it worse.

Also, reflux is usually a problem when lying down at night, and most MG patients take less Mestinon at night.