Methods Advantages Disadvantages Suitability for early erosion Type of analysis Microhardness -Relatively low costs -Nondestructive technique - Not evaluate wear Suitable Quantitative Surface Profilometry -Nondestructive technique -Evaluate wear - Not time-consuming - Perfectly flat and polished specimens - Mechanical profilometry could damage surface Limitedly suitable Quantitative Surface roughness - Evaluate texture - Not time-consuming - Suitable Quantitative Microradiography -Evaluate mineral loss and demineralization - Destructive technique Not suitable Quantitative Atomic Force Microscopy and -Nondestructive technique - Very sensitive - Time-consuming - Long experience -High costs Suitable Qualitative AFM Nanoindentation -Allow the measurement of nanomechanical properties such as surface hardness and reduced elastic modulus - Nondestructive technique - Time-consuming - Demanding sample preparation Suitable Quantitative SEM -High resolution - Evaluate micromorphological alteration -Destructive technique -Specimens need be coat with a conductive layer - High costs Suitable Qualitative White Light interferometer - Nondestructive technique -Could evaluate native surfaces -Determine roughness and wear -Emerging technique -Long experience Limitedly suitable Quantitative Confocal Laser Scanning Microscopy -High resolution -Nondestructive technique - Long experience Suitable Qualitative

Table 1: Survey of the methods described in the text with respect to advantages and disadvantages, suitability for use with erosion (after few minutes of acidic challenge), as well as to type of analysis (quantitative or qualitative)