A State-of-the-Art Review on the Wear of the Occlusal Surfaces of Natural Teeth and Prosthetic Crowns

Abstract

This review focuses on the wear mechanisms of natural and restorative dental materials, presenting a comprehensive description and analysis of the works published in the last two decades on the wear at the interface of occlusal surfaces. Different groups of tribological pairs were considered: tooth-tooth, tooth-restorative material (tooth-ceramic, tooth-resin-based-materials, and tooth-metal), and restorative-restorative materials. The lack of standardization of the wear tests impairs the direct comparison of the obtained results. However, it was possible to infer about the main wear mechanisms observed on the different classes of dental materials. Concerning ceramics, their toughness and surface finishing determines the wear of antagonist tooth. Abrasion revealed to be the main wear mechanisms at occlusal interface. In the case of resin-based composites, the cohesion of the organic matrix and the nature, shape, and amount of filler particles greatly influences the dental wear. The protruding and detachment of the filler particles are the main causes of abrasion of antagonist enamel. Metallic materials induce lower wear on antagonist enamel than the other classes of materials, because of their low hardness and high ductility. Most of the studies revealed plastic deformation and adhesive wear as the main wear mechanisms. Overall, more research in this area is needed for a better understanding of the mechanisms involved at the occlusal surfaces wear. This would be essential for the development of more suitable restoration materials.

Keywords: biotribology; dental restorative materials; natural teeth; occlusal surfaces.

Figure 1

Materials currently used in dental restorations.

Figure 2

(A) Pin-on-plate configuration; (B) chewing simulator set-up; (C) clinical studies (Images (A) and (B) are reproduced from [28] and [29], respectively, with the permission of Elsevier, who is acknowledged).

Figure 3

Enamel wear loss as a function of hardness reduction. DW: distilled water (pH = 7); CA: citric acid; AA: acetic acid. (reproduced from [41]).

Figure 4

SEM images of zirconia (A) tested against natural human dental cusps (B) in a chewing simulator (reproduced from [28]).

Figure 5

Wear tracks in lithium disilicate plates after pin-on-plate tests in artificial saliva at pH = 7 using natural cusps as pins (reproduced from [50]).

Figure 6

Scheme of the wear mechanisms occurring in the interface of enamel/ceramic prosthetic material.

Figure 7

SEM images of (A) Vita Enamic after testing against natural human dental cusps in a chewing simulator, showing the degradation of the organic matrix of the prosthetic material; (B) surface of the dental cusp after the wear test against Vita Enamic, showing abrasive wear (reproduced from [28]).