I did this question some weeks ago, and from the answers, I have to tell that probably BEWE is a good choice. 

Dixon B, Sharif M, Ahmed F, Smith A, Seymour D, Brunton P. Evaluation of the basic erosive wear examination (BEWE) for use in general dental practice. British Dental Journal [serial online]. August 11, 2012;213(3):E4. Available from: Academic Search Premier, Ipswich, MA. Accessed March 30, 2015.

http://www.elearningerosion.com/en.html

Bartlett, D., Ganss, C., & Lussi, A. (2008). Basic Erosive Wear Examination (BEWE): a new scoring system for scientific and clinical needs. Clinical Oral Investigations, 12(Suppl 1), 65–68. doi:10.1007/s00784-007-0181-5 

Dear Mariela and Mina, thank you very much for the suggestions and links, I will look into it!

Best Regards,

Françoise

Those are all subjective indices. The objective method that can tell you wether the erosive wear is progressing or arrested is Silicone Index.

Amaechi BT, Higham SM. Dental erosion: possible approaches to prevention and control.(Invited review) J Dent 2005 Mar;33(3):243-252.

Dear Professor Amaechi, 

Thank you very much for answering. I've been looking into several indices for quite some time, and indeed most are based in subjective criteria.

If I may ask an additional question, is there a clinical threshold to distinguish a normal wear from pathological wear (maybe age related?)

Thank you again

I completely agree with Dr Amaechi - and unfortunately as dentists we haven't yet developed any useful mainstream methods for accurately detecting early tooth surface loss in vivo. BEWE is perhaps useful as a screening tool for research, but has serious drawbacks when used for clinical note taking and treatment planning. The suggested management strategies bear little resemblance to the approaches adopted by many restorative consultants in the UK, and the index is actually quite difficult to use, as it isn't particularly discriminatory at the extremes of the scale. Personally I find a simplified Smith and Knight index useful to grade (1-4) the severity of tooth surface loss. The Tooth Wear Index is an example of a well thought out and fairly comprehensive index - but it is almost too time consuming, and relatively complex unless used often.

Hope this helps!

Françoise'

Tooth wear in principle is a physiological process occurring from normal functioning of the dentition throughout lifetime.However, tooth wear can be regarded as pathological if the teeth become so worn that they do not function effectively or seriously mar the appearance before they are lost for other causes or the patient dies. The distinction of acceptable and pathological wear at a given age is based upon the prediction of whether the tooth will survive the rate of wear.

Thank you very much for the answers!