My teeth have recently become more sensitive than they were before. is this cause for concern?

Worth investigating: See your Dentist to determine the cause of sensitivity, and thus the correct treatment. Could be caused by, among other things, gum disease resulting in root exposure, cavities, fractures, malocclusion causing abfractures, change in diet or medication, etc.

More info needed...: Are they sensitive to sweets? Cold? When you bite down? Different causes can include cavities, gingival recession, and bruxism. If it has been more than six months since your last dental exam and cleaning, now is the time to call for an appointment.

Yes: See a dentist to find out what is causing your sensitivity. It could be decay or a number of other causes.

Yes: Pain of any sort is a warning that there may be an issue requiring treatment. That treatment will vary dramatically depending on what is causing the discomfort. The only safe way to proceed is to get it looked at, get a diagnosis, then decide on a treatment plan. That plan could be anything ranging from using a desensitizing toothpaste to tooth extraction. Good luck!

Of course: There may be number of reasons for your sensitive teeth. Some of the causes include tooth decay, a cracked tooth, worn tooth enamel or teeth clenching at night. See your dentist for examination and treatment.