High levels of stress can have an effect on so many areas of life. And one of those areas is your mouth.
Stress can bring on cold sores or canker sores. These usually last for a week to 10 days. Avoiding spicy or high acid foods can help relieve irritation from some mouth sores. High levels of stress can leave you clenching or grinding your teeth. Grinding your teeth can bring on something called temporomandibular joint (TMJ) pain. A night guard that you wear for sleep may help.
If you're down in the dumps from stress, you may let your personal care habits slip. If one of those habits is your formerly good oral hygiene, you can be at greater risk for periodontal disease and cavities. High levels of stress can lead to increased dental plaque, bleeding gums or gingivitis.
"Remember, eating a balanced diet, seeing your dentist regularly, and good oral hygiene help reduce your risks of periodontal disease. Make sure you brush twice a day and floss daily. Also, using an antibacterial mouthwash or toothpaste can help reduce the number of bacteria in the mouth that cause gingivitis and other periodontal diseases."
http://www.webmd.com/oral-health/healthy-mouth-and-body-9/stress-teeth?ecd=wnl_day_052710