Those faint lines are often just craze lines: shallow, surface-level cracks in the enamel that usually don’t affect tooth strength or cause pain. They’re common, especially with age, and can become more visible as they pick up stains from coffee, tea, wine, or smoking. Normal chewing, temperature swings between hot and cold drinks, and small habits like nail biting or pen chewing all add up over the years, creating micro-cracks that most people never notice until they start to show.

However, not every crack is harmless. Heavy nighttime grinding, clenching from stress, biting hard objects, or old dental work that alters your bite can push teeth past their limits. Warning signs include sharp pain when biting, sensitivity to hot or cold, or a tooth that darkens or changes color. If you see new cracks or feel discomfort, a dentist can examine them under magnification, adjust your bite, smooth or bond vulnerable areas, and recommend a night guard if you grind. With early attention and small habit changes, you can usually keep those fine lines from turning into fractures that threaten the tooth itself.