OBJECTIVE To evaluate in vitro the potential of an intraoral scanner (IOS) to monitor erosive tooth wear (ETW) using different alignment software with distinct quantitative measurement metrics. METHODS 15 unpolished bovine crowns were exposed to citric acid (pH ~2.5) at 24-hour intervals up to 168 hours. At baseline and after each acid exposure episode, the teeth were scanned with IOS (3Shape TRIOS 3). Scanned images from each data point were superimposed on baseline image using WearCompare software to obtain volume loss (mm³) and area loss (mm²) and using IOS built-in software (3Shape TRIOS Patient Monitoring) to obtain depth loss (mm). Pearson's test was used to determine the correlation between acid exposure time (h) and each outcome measure (α= 0.05). RESULTS As the acid exposure time increased, the lesion parameters (depth, volume, and area) increased. Friedman's test showed that relative to baseline volume loss became significant (P< 0.05) after 72 hours from median 11.48 mm³ (IQI 25% = 8.72 mm³), eroded area became significant (P< 0.05) from median 48.67 mm² (IQI 25% = 44.46 mm², P< 0.05) after 96 hours, and erosion depth became significant (P< 0.05) from median 0.69 mm (IQI 25% = 0.66 mm²) after 144 hours. A strong correlation was observed between depth (mm²) and time (r= 0.9993 P< 0.0001), volume (mm³) and time (r= 0.9968, P< 0.0001), and area (mm²) and time (r= 0.9475, P= 0.0003). CONCLUSIONS Currently, there is no quantitative method for clinical monitoring of erosive tooth wear. The present study demonstrated that the intraoral scanner is a potential clinical tool for detecting and quantitatively monitoring early and advanced erosive tooth wear.