Abfraction Theory: Controversy Analysis, Scoping Review

Abstract

Purpose of review The aim of this review was to describe in detail the aetiological events involved in the abfraction phenomenon, examining the action of irregular occlusal forces, analysing the evidence supporting this aetiological hypothesis, and highlighting the controversies surrounding this theory. Recent findings Noncarious cervical lesions (NCCLs) are the result of two widely accepted pathological mechanisms: erosion and abrasion. These lesions generally affect adults after the age of 30, and approximately 10–40% of adults in this age bracket have this condition. Premolars are the primary teeth affected by NCCLs. Characteristic symptoms include progressive and ongoing loss of mineralized tissue, primarily on the buccal surfaces of collars. As the dentine is exposed, the tooth becomes increasingly sensitive. Over time, the lesion tends to deepen towards the dental pulp, and the dental crown or pulpitis may fracture. Both abrasion and erosion alone cannot fully explain all types of NCCLs. For some lesions, this difference appears to be related to an aetiopathological mechanism defined as abfraction, which combines the aetiological events of erosion and abrasion with the application of irregular occlusal loads along the occlusal surfaces of dental crowns. This study was conducted by following the PRISMA protocol guidelines for scoping reviews, and the protocol was registered on INPLASY prior to execution. The studies were identified through literature searches in the PubMed and Scopus databases using the following keywords: "abfraction" and "NCCL". The risk of bias was assessed using ROBINS-I. Summary The search led to the inclusion of only 6 studies out of a total of 1449 identified articles. The analysis of these studies, which correlated the progression of NCCLs to the forces applied to the teeth, did not provide sufficient evidence to confirm or refute the aetiological role of occlusal loads in the onset of abfractions. However, clues emerged that would require further confirmation through prospective longitudinal studies, which must consider the inclusion of other aetiological mechanisms, such as abrasion and erosion.