missing tooth

Question
I just discovered that my rat only has one tooth on the bottom. I don't know if this was a birth defect or if it has just happened, but she's skinny and not eating much and not able to groom herself well.
I just want to know if this happens a lot, if theres anything I can do, and if it will grow back,etc.
thank you
shire

Answer
 Sometimes the tooth can break off from an injury or a dental abscess can cause the tooth to rot away or grow improperly.  If she was otherwise acting normally I would say don't worry about it, but since she is losing weight she probably isn't able to eat correctly, either because she can't gnaw properly or because she is in pain, she will probably need to be seen by a veterinarian.  An x-ray should be able to tell if the tooth is still there and where it is if it is growing incorrectly.

 There really isn't anything you can do on your own to help the tooth, but to help her eat you can mush up her food so it can be eaten without gnawing.  You may want to look into purchasing some NutriCal, which is a high-calorie paste that rats love and will help her gain some weight back.

 Whether or not it grows back depends on the problem.  I had a rat once with a dental abscess that was unnoticed since it was not visible on the outside and it ended up rotting away part of his jaw.  His tooth then grew incorrectly, ending up piercing through his skin and back through.  My vet removed it and it never grew back and he had no problems with it.  If it was just broken it will likely grow back eventually.

 One other thing to keep in mind is that she may not be able to brux (grind her teeth) properly and her top teeth may overgrow as a result.  Usually they compensate for this and there are no problems but if she is in pain she may not want to brux at all since doing so hurts her.

 You'll definitely have to take her to the vet, who will be able to look in her mouth with a special instrument and see the problem, and x-ray her if necessary.  Drugs may have to be prescribed for pain or to help stop swelling or bacteria if it is caused by an abscess.

 Well I hope everything turns out all right, let me know what happens!  Good luck!