Investigation into the validity of WearCompare, a purpose-built software to quantify erosive tooth wear progression

Objectives: The use of surface matching software with intraoral scanners is developing rapidly which increases the need for accessible, accurate and validated measurement software. This investigation compared the current gold-standard Geomagic Control software to a purpose-built software “WearCompare”.

Methods: Artificially created occlusal defects of a known size were created on 10 natural molar teeth scanned with a structured-light model-scanner (Rexcan DS2, Europac 3D, Crewe). The volume change, maximum profilometric loss and mean profilometric loss were obtained from both Geomagic Control (3D Systems, Darmstadt, Germany) and WearCompare (leedsdigitaldentistry.com). Duplicated datasets were randomly repositioned and re-alignment performed. The effect of the re-alignment was calculated by analysing differences between the known defect size and defect size after re-alignment using the same measurement metrics. Lastly, clinical wear measurements were compared on natural molar surfaces (n = 60) over 6 months using study models collected from a previous longitudinal trial. Data analysis was performed in SPSS v25 (paired t-tests, Pearson correlations, p < 0.05).

Results: Measurement correlation between the softwares was greater than 0.97 (p < 0.001) for all measurement metrics. The volume change error (SD) after alignment was −0.67 mm3(1.14) for Geomagic and −0.06 mm3(0.93) for WearCompare (p = 0.140 and r = 0.065, p = 0.86). Measurement errors were observed after alignment in both softwares and no statistical differences were observed between softwares. The volume change on the clinical dataset over 6 months was +0.29 mm3(3.97) in Geomagic and −0.30 mm3(1.82) for WearCompare (p = 0.19 and r = 0.61, p < 0.001). The mean profile gain was 42.86 μm(40.19) for Geomagic and 32.17 μm(23.72) for WearCompare (p = 0.048). Correlations between the softwares were greater than 0.6 for all measurement metrics except for mean profile gain.

Significance: WearCompare is a comparable tool to Geomagic for quantifying erosive tooth wear. WearCompare reported statistically less profile gain indicating less error but further research is needed to reduce the human errors in both softwares.