Objective: to develop a tooth wear index capable of objectively classifying and quantifying the progression of tooth wear using accurate 3D scanning data of tooth wear in patients.

Materials and methods: a 3D tooth wear scanning protocol, aimed at in-vivo monitoring of tooth wear progression, was developed and assessed using a calibrated reference model. The methodology involved taking polyether impressions of the dentition, pouring impressions in Type IV stone and scanning the resultant casts using a 3D contact-scanner. Thereafter, eleven tooth wear patients were recruited (n=130 teeth) with participants’ dentitions scanned initially and after twelve months. The resultant 3D scan data, demonstrating depth, surface area and distribution of tooth wear, were analysed and employed to formulate a novel 3D tooth wear index.

Results: all study-participants demonstrated ≥140µm of tooth wear over a period of twelve months. All participants had one or more teeth with ≥260µm tooth wear. However, the wear affected surface area was ≤4% in the majority of scanned teeth (n=104/ 130). Based on clinical data, the proposed 3D scanning index classifies tooth wear according to depth (Grade 1: 140 – 260 µm, Grade 2: 260 – 380 µm and Grade 3: 380 - >500 µm), surface area (Class A: 0- 4%, Class B: 4- 8% and Class C: ≥8%), and distribution (Localised tooth wear: affecting ≤ 30% of teeth with Grade 1 or more wear-depth. Generalised tooth wear: affecting >30% of teeth with Grade 1 or more wear-depth).

Conclusion: the proposed tooth wear index offers an objective means to clinically assess and monitor tooth wear progression in patients using quantitative 3D scan data acquired through a standardised, calibrated and repeatable scanning protocol.