Abfraction: separating fact from fiction

Abstract

Non-carious cervical lesions involve loss of hard tissue and, in some instances, restorative material at the cervical third of the crown and subjacent root surface, through processes unrelated to caries. These non-carious processes may include abrasion, corrosion and possibly abfraction, acting alone or in combination. Abfraction is thought to take place when excessive cyclic, non-axial tooth loading leads to cusp flexure and stress concentration in the vulnerable cervical region of teeth. Such stress is then believed to directly or indirectly contribute to the loss of cervical tooth substance. This article critically reviews the literature for and against the concept of abfraction.Although there is theoretical evidence in support of abfraction, predominantly from finite element analysis studies, caution is advised when interpreting results of these studies because of their limitations. In fact, there is only a small amount of experimental evidence for abfraction. Clinical studies have shown associations between abfraction lesions, bruxism and occlusal factors, such as premature contacts and wear facets, but these investigations do not confirm causal relationships. Importantly, abfraction lesions have not been reported in pre-contemporary populations.It is important that oral health professionals understand that abfraction is still a theoretical concept, as it is not backed up by appropriate clinical evidence. It is recommended that destructive, irreversible treatments aimed at treating so-called abfraction lesions, such as occlusal adjustment, be avoided.

The survival of Class V restorations in general dental practice: part 3, five-year survival

“…37 Similarly, consideration should perhaps be given to using RMGI more frequently in the restoration of NCCLs, as other studies have also shown high retention rates in comparison to other materials. 38,39 Occlusal factors are considered by many to be important in the aetiology of NCCLs [40][41][42] and in the success of restorations.…”

“…43,44 This study, however, did not identify any statistically significant effect of any of the occlusal factors recorded on time to failure, which supports the findings of those who discount the influence of occlusal loading as anything more than a co-initiating factor. 37,56 No evidence of an association between the elastic modulus of a restorative material and time to failure was found, as there was no difference observed between the Kaplan-Meier plots of either of the two composite types and compomer, while glass ionomer, the material with the lowest modulus of elasticity, recorded the greatest proportion of failures. The issue of elastic modulus is somewhat complicated as materials within one classification may have quite distinct mechanical properties and so it cannot necessarily be assumed, for example, that all composites have a significantly higher elastic modulus than all RMGIs.…”

The survival of Class V restorations in general dental practice. Part 2, early failure

“…19 However, in this study there was no evidence to support early failure of restorations being significantly associated with any of the occlusal features recorded, which lends further support to recent reviews which question the role of occlusion in the development of non-carious cervical lesions (NCCLs). 20,21 In the univariate analysis, contamination with moisture and level of oral hygiene did not appear to increase two-year failure; however the general level of moisture contamination was minor and only 10% of patients displayed poor oral hygiene. Although no significant association with moisture contamination was identified using univariate analysis, the multivariable analysis suggested that moisture contamination increased the chance of early failure, after adjusting for other important factors.…”

Computerized occlusal analysis in Dentofacial orthopedics: indications and clinical use the T-scan III system

“…Clinical studies have shown that they are associated with bruxism, wear facets, and premature contacts but no investigations have been able to confirm any causal relationship 15,30 .…”

“…In conclusion, it is no longer deemed advisable to use selective grinding in an attempt to cure abfraction lesions 30,36 . Nevertheless, in the framework of orthodontic treatment, it may be worthwhile for orthodontists to discern specific areas of interference and to modify the values of lateral torque during finishing stages of treatment.…”