One of the most critical aspects in introral impression is the detection of the finish line, in particular in case of subgingival preparations. The aim of these in vitro study was to evaluate the accuracy among four different IntraOral Scanners (IOSs) in scanning a subgingival vertical margins preparation (VP). A reference maxillary typodont (MT) was fabricated with a VP for full crown on #16 and #21. The MT was scanned with a laboratory scanner (Aadva lab scanner, GC, Tokyo, Japan) to obtain a digital MT (dMT) in .stl format file. A group of 40 digital casts (dIOC) were obtained by scanning the MT 10 times with four different IOSs (Trios 3, 3Shape A/S), ( I700, Medit), (Vivascan, Ivoclar), (Experimental IOS, GC). All the obtained dIOCs were imported into an inspection software program (Geomagic Control X; 3D SYSTEMS) to be superimposed to the dMT, to calculate trueness. Therefore, in order to calculate precision all the scans of the same scanner group were superimposed onto the cast that obtained the best result of trueness. Results were collected as root mean square value (RMS) on #16 and #21 abutment surfaces and on a marginal area positioned 1 mm above and below the gingival margin. A nonparametric analysis Kruskal-Wallis test was performed to compare the RMS values obtained in the different iOS groups for trueness and precision. Statistically significance was set at 0.05. The trueness on #16 abutment, did not statistically differ in between the IOS, while on #21 abutment, Vivascan (56.0 ±12.1) and Experimental IOS, GC (59.2±2.7) performed statistically better than the others. Regarding precision Experimental IOS, GC and Trios 3 were significantly better than I700 and Vivascan both in the #16 (10.7±2,1; 15.8 ± 2,7) and in the #21 area (16.9±13.8 ; 18.0±2.7). At marginal level for both #16 and #21 all the IOS reported reduced accuracy compared to clinical acceptance.