If you ignore a dental cavity long enough, the cavity symptoms will eventually be hard to miss. For example, years of drinking three cold sodas a day might eventually cause a toothache. That toothache is actually a common symptom of a dental cavity. Another sign of a tooth cavity is bad breath. If you’re experiencing one or more cavity symptoms, take a peek inside your mouth. An easy way to spot a dental cavity is to simply look at your teeth — if you see holes or pits, they are probably dental cavities. Some dental cavities, however, can only be detected by using X-rays or other sophisticated dental equipment.