Surface Damage Analysis of Occlusal Veneers

After mechanical testing, when the static loading forces were applied, the degree of surface damage of the occlusal veneers of both groups of specimens (exposed and non-exposed to acidic artificial saliva), were examined using a scanning electron microscope (Inspect S, FEI, Tokyo, Japan). SEM analysis parameters were high vacuum (HV) mode, 20 kV, ETD (Everhart–Thornley detector for secondary electrons), with two magnification orders: 100× general overview for the specimens which are not exposed to acidic artificial saliva and another, at a higher surface topography (250×) for the specimens exposed to acidic artificial saliva. The failure degree of restorations surface damage, before and after immersion in acidic artificial saliva, was assess according to the following classification [14 (link)]:

First failure degree (I)—the appearance of extensive cracks at the surface of restorations;

Second failure degree (II)—the restorations were fractured;

Third failure degree (III)—both restorations and tooth structure were fractured;

Fourth failure degree (IV)—the appearance of longitudinal and profound fractures of the restorations as well as tooth structure fractures.

For a better understanding of the experimental part effectuated in this study, in Fig. 5 is pictured the entire schematic protocol.Fig. 5

Schematic protocol of the study