TL;DR
Cavity depth and tooth structure thickness significantly influenced the accuracy of intraoral scanners in endocrown restorations and significantly influenced the accuracy of intraoral scanners in endocrown restorations.
OBJECTIVE To evaluate the effects of pulp chamber depth, tooth type, and intraoral scanner (IOS) on the accuracy of endocrown digital impressions. MATERIALS AND METHODS Standardized endocrown preparations with 2 and 5 mm pulp chamber depths were performed on molar and premolar typodonts. Digital impressions were obtained using three IOSs (Dexis, iTero, and 3Shape). Reference scans were acquired using a laboratory scanner. Accuracy was assessed following best-fit alignment. Cavity base and axial regions were separately evaluated. Data were analyzed using Kruskal-Wallis and Dunn post hoc tests (α = 0.05). RESULTS Pulp chamber depth, tooth type, and IOS significantly affected scanning accuracy (p < 0.05). Increasing cavity depth increased deviations at cavity base while reducing deviations at axial region. Premolar preparations with 5 mm depth exhibited the highest cavity base deviations (99.5-107.2 μm). At axial region, iTero demonstrated the lowest deviations (28.2 μm) in 5 mm depth molar preparations. Dexis and iTero showed comparable performance at cavity base. CONCLUSIONS Effect of cavity depth was region-dependent, negatively affecting cavity base while improving accuracy at axial region. Molar preparations demonstrated superior cavity base trueness, whereas premolar preparations exhibited better axial region trueness. Deep premolar preparations represented the most challenging condition for accurate digital acquisition.
Evaluating how different ISB designs affect the trueness and precision of digital impressions in a completely edentulous maxillary arch with multiple implants found significant differences were found among ISBs in both trueness and precision.
OBJECTIVE The accuracy of intraoral scanners is commonly described by trueness and precision; however, the extent to which single-tooth crown preparation geometry influences these outcomes across different scanner systems remains unclear. This in vitro study aimed to evaluate trueness and to descriptively assess precision across different preparation designs and scanner systems. METHODS A maxillary phantom model with nine single-tooth crown preparation designs and one unprepared control was scanned with Trios 5 and Primescan. For trueness, each preparation-scanner combination was scanned five times and compared with a high-accuracy industrial reference scan (ATOS Q) using RMS deviation after best-fit alignment. Trueness was analyzed with two-way ANOVA. Precision was evaluated descriptively using the interquartile range (IQR) of repeated scan RMS values. RESULTS Trueness RMS values ranged from 0.0247 to 0.0623 mm. The lowest value was observed for occlusal veneer (VE3; partial occlusal) scanned with Trios 5, and the highest value was observed for anterior veneer (VE2; buccal + palatal) scanned with Primescan. Preparation design significantly affected trueness (F(9, 80) = 9.26, p < 0.001), while scanner type showed no statistically significant difference (p = 0.056); the preparation design × scanner interaction was significant (F(9, 80) = 4.84, p < 0.001). Precision varied across preparation designs and scanner types, as reflected by differences in IQR values. CONCLUSIONS Cavity preparation geometry significantly affected IOS trueness, and this effect was scanner-dependent. Simpler and more optically accessible geometries generally showed lower RMS deviations, although this pattern varied according to specific preparation features. Precision, assessed descriptively using IQR values, varied across preparation designs and scanner systems and should be interpreted cautiously.
Both Medit i900 and Dexis IS 3800W provided clinically acceptable accuracy for Kennedy Class I mandibular arches, and accuracy was influenced by scanner type, tip size, and scanned area.
Aim This study aimed to evaluate and compare the accuracy of four intraoral scanners (IOS) in capturing the three-dimensional positions of orthodontic brackets on dental models. Methods Twenty maxillary dental models bonded with MBT stainless steel brackets were scanned using four IOS systems: Primescan, Trios 4, iTero Element 5D, and Medit i700. A high-accuracy laboratory scanner served as the reference standard. Each model was scanned twice with each IOS, yielding 160 datasets. Scans were aligned to the reference using a two-step superimposition protocol, and bracket slot-center deviations were measured in mesiodistal, occlusogingival, buccolingual, and angular dimensions. Trueness, precision, and clinically acceptable deviation rates were analyzed using ANOVA/Kruskal–Wallis tests and intraclass correlation coefficients (ICC). Results Primescan showed the highest trueness, with linear deviations of 0.05–0.07 mm and angular deviations of 0.58–0.62°. Trios 4 demonstrated similar accuracy, remaining within ±0.10mm and ± 1°. iTero Element 5D exhibited greater variation (0.10–0.12mm; 1.12–1.25°), while Medit i700 showed the highest deviations (0.11–0.13mm; 1.29–1.41°). Clinically acceptable deviation rates were 92.5% for Primescan, 88.1% for Trios 4, 76.4% for iTero, and 62.7% for Medit. Precision analysis showed the lowest repeat-scan variability for Primescan (0.03 ± 0.01 mm), whereas Medit displayed the highest variability. ICC values exceeded 0.90 for all scanners. Conclusion Scanner accuracy varied significantly, with Primescan and Trios 4 demonstrating superior trueness and precision. iTero and Medit showed reduced accuracy, particularly in angular measurements. Scanner selection is therefore critical for workflows requiring high-fidelity bracket capture.
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