Intraoral scanning of endocrown preparation on natural teeth in an in-vitro setting: a segmented trueness analysis

Compare five technologies of intraoral scanning on the digitization of the the pulpal floor, internal and external axial walls, and margins of natural teeth prepared for endocrown restoration.

One lower molar was freehand prepared for endocrown restoration with a cavity depth of 5 mm. The preparation was scanned five times (n=5) using Primescan, i600, TRIOS 3, IS 3700, and Eagle IOS. A reference digital cast was obtained using a laboratory scanner. Quantitative analysis of discrepancies (RMS) was performed using Geomagic Control X across segmented areas: pulpal floor, internal and external axial walls and margin of the preparation. RMS values were compared using one-way ANOVA.

Primescan showed the lowest RMS values at the pulpal 13.38 ±2.23μm (p<0.001). The devices i600, IS 3700 and TRIOS 3 had similar performance (p>0,05). At the internal axial wall, Primescan exhibited the lowest values 10.80 ±0.78μm, with no statistical difference compared to TRIOS 3 (p>0.05). At the external axial wall, Primescan recorded the lowest values 8.52 ±0.30μm, with no statistical difference compared to TRIOS 3 (p>0.05). At the margins Primescan had the lowest value 9.40 ±0.62μm, but statistically equal to TRIOS 3 (p>0.05). Eagle IOS had the highest values in all regions.

Different IOS technologies perform differently across preparation regions. The pulpal floor, internal axial wall and margin are the most affected. However, all values remained below clinically acceptable thresholds.