Because of this controversy the true causes of abfraction also remain disputable. Researchers have proposed that abfraction is caused by forces on the tooth from the teeth touching together, occlusal forces, when chewing and swallowing. These lead to a concentration of stress and flexion at the area where the enamel and cementum meet (CEJ). This theoretical stress concentration and flexion over time causes the bonds in the enamel of the tooth to break down and either fracture or be worn away from other stressors such as erosion or abrasion. The people who initially proposed the theory of abfraction believe the occlusal forces alone cause the lesions without requiring the added abrasive components such as toothbrush and paste or erosion.If teeth come together in a non-ideal bite the researchers state that this would create further stress in areas on the teeth. Teeth that come together too soon or come under more load than they are designed for could lead to abfraction lesions. The impacts of restorations on the chewing surfaces of the teeth being the incorrect height has also been raised as another factor adding to the stress at the CEJ.Further research has shown that the normal occlusal forces from chewing and swallowing are not sufficient to cause the stress and flexion required to cause abfraction lesions. However, these studies have shown that the forces are sufficient in a person who grinds their teeth (bruxism).
Many researchers argue that this is inaccurate as they contend that the abfraction lesion is a multifactorial (has many causative factors) lesion with other factors such as abrasion or erosion. This controversy around the causative factors, along with the recency of the lesion classification, are some of the reasons why many dental clinicians are looking at the lesion with some scepticism. More research is needed to fully clear up the controversy surrounding the abfraction lesion. See also
Tooth wear
Abrasion
Attrition
Bruxism
Erosion

References

Summit, James B., J. William Robbins, and Richard S. Schwartz. Fundamentals of Operative Dentistry: A Contemporary Approach. 2nd edition. Carol Stream, Illinois, Quintessence Publishing Co, Inc, 2001. ISBN 0-86715-382-2. Lee, WC. ; Eakle, WS. (1984). "Possible role of tensile stress in the etiology of cervical erosive lesions of teeth". Journal of Prosthetic Dentistry. 52 (3): 374–380. doi:10.1016/0022-3913(84)90448-7. PMID 6592336.