Problems can occur if a Chihuahua has a moderate to extreme undershot or an overshot jaw. With minor misalignment, not much will need to be done though the teeth will need to be monitored.
More serious problems may require some teeth to be removed and possible jaw surgery. This includes:
A Wry Mouth -
This refers to when one side of the mouth is much longer than the other or the jaws are out of alignment. It can cause pain in the mouth, problems with eating
and leave teeth very vulnerable to infection.
An issue that does not affect the jaws at all, however the teeth themselves are moderately to severely crooked teeth). There are 2 main causes for this:
Genetics - This is thought to be an inherited fault for some Chihuahuas. Though, with proper breeding practices, a Chihuahua with malocclusion should not be bred.
Premature detachment of the puppy's milk teeth. Adult canine teeth follow the trail of the wispy thin roots of the milk teeth as the path in which to emerge.
If milk teeth detach before they fall out naturally, this causes an issue in which those adult canines do not have a clear path to erupt. They will then surface at random, odd, and slanted angles which can cause a mouthful of crooked teeth.
For this reason, it is important to refrain from any action that would interfere with the puppy's teeth. It is highly recommended to not play 'Tug of War' or any game with a toy that will tug at the small milk teeth.