It is associated with Bruxism.
ABFRACTION lesions arises from clenching and is more common in the back (posterior) teeth and the canines but they can occur in the front (anterior) teeth as well. The characteristic appearance is of a straight line break parallel to the occlusal plane near the gumline and it causes the gums to recede. The straight line wedge breakage is a feature of the stress fracture of a hard tooth structure from the bending of the tooth when you gnash them together and move your jaw side to side. Studies have shown that when you do this in your sleep it can be up to 40 times stronger than you could do it when you are awake. You could not do it even if you tried when you are conscious as your higher brain will stop you from doing so. Bruxism is proportional to stress.
Secondary Effects
When the enamel has broken the dentine ( soft part of the tooth underneath the enamel) can erodes giving these lesion the appearance of acid erosion and toothbrush abrasion. You can of course get decay in these areas once broken as it can become a food trap. While it is possible to have the acid erosion, I do not believe toothbrush abrasion is a likely culprit. These are secondary to the main issue of the abfraction which is in fact the result of bruxism.
Early Warning Symptoms
Long before the visible signs of abrasion are detected you will feel the sensitive teeth as an early warning that you are abfraction your teeth. Because abfraction is due to bruxism all the associated symptoms of bruxism should be use as an even earlier warning of the impending damage of abfraction. By the time you feel the sensitive teeth – usually cold – your teeth has already started to break even if you can see it yet. Remember the damage is irreversible. You can only hope to stop the progress by firstly being aware and secondarily using an occlusion splint at night when you sleep.
The lost of your canine prominence accelerates the abfraction of the posterior teeth. It is important to reestablish canine disclusion if you have worn down your canines or orthodontically establish it if your bite is not correct.
No Ordinary Dentistry 