Anadioti et al., 2014 [12]In vitro studyE4D scannerPVS impressions Triple scan protocol and 2D measurements measured at 4 points Marginal fit PVS impression and press fabrication technique the most accurate for 3D and 2D marginal fits.Neves et al., 2014 [23]In vitro studyCEREC 3D Bluecam and E4D scannerPVS impressions Scanned with μ-CT. For every image 2 measurements were taken for horizontal and vertical fit at 400× magnification. The crowns were fixed to the die with silicone material.Marginal fit Lithium disilicate crowns fabricated using CEREC 3D Bluecam scanner CAD/CAM system or the heat press technique more accurate than crowns fabricated using an E4D Laser scanner system.Ng, Ruse and Wyatt, 2014 [24]In vitro studyLava COS scanning unitPVS impressionsCircumferential
marginal gap measurements takenat 8 measurement locations. photographs at 40× with a
Die was held in place with a measurement alignment chuckMarginal fit The fully digital fabrication method provided better margin fit than the conventional methodAbdel-Azim et al., 2015 [25]In vitro studyLava COS scanning unit and iTeroPVS impressionsStereomicroscope with a microscope camera used at 45× magnification and measured at 4 points. A computer software used. Marginal fit Digital and conventional impressions were found to produce crowns with similar marginal accuracyKim et al., 2016 [26]In vitro studyCS3500/
TRIOS/
Ceramill Map400PVS impressionsCrowns were cemented to replica die with zinc phosphate cement and finger pressure. 2D and 3D measurements were used to measure the marginal gap. Internal volume measured using volume of zinc phosphate cement between lithium disilicate crown and replica die.Marginal fit and internal volumeSignificant differences were found between e.max CAD crowns produced using 2 intra-oral digital impressions.Alqahtani, 2017 [27]In vitro studyCEREC omnicam and TRIOSPVS impressionsA loading device was used to apply an occlusal load of 3 lbs during the measurement. Scanning electron microscope at a magnification of 50× used to measure. Three measurements were taken for each point, and average was recorded.Marginal fitAll-ceramic crowns, fabricated using the CAD/CAM system, show a marginal accuracy that is acceptable in clinical environ- ments. The TRIOS CAD group displayed the smallest marginal gap.Zeltner et al., 2017 [28]Randomised controlled trialLava, iTero, CEREC inLab, and CEREC infinident systemsPVS impressionsReplica technique used applying finger pressure. Replica sectioned and measurements taken with light microscopy at 200× magnification using a blinded investigator. Marginal and internal fit No significant differences were found between the conventional and digital workflows for the fabrication of monolithic lithium disilicate crowns.Azar et al., 2018 [29]In vitro studyCEREC OmnicamPVS impressionsMeasurements taken using an optical microscope at 200× magnification. The measurements were performed on 25 points on the finishing line of each toothMarginal fit Lithium disilicate crowns fabricated with the press technique have measurably smaller marginal gaps compared with those fabricated with CAD/CAM technique.Mostafa et al., 2018 [30]In vitro studyLava C.O.S. scanning unitPVS impressionsCrowns were seated using finger pressure and wax. 3D volume was measured circumferentially based on a standardized number of slices for the selected region of interest. Vertical marginal gaps were also measured.Marginal fit The results suggested that digital impression and CAD/CAM technology is a suitable, better alternative to traditional impression and manufacturing.Revilla-Leon et al., 2018 [31]In vitro study Laboratory based scanner Renishaw DS20. PVS impressionsComputed tomography (μ-CT) for measurement of marginal and internal gaps. Marginal and internal fit All the groups presented less than 100 μm marginal and internal gap. The best marginal and internal fit was still obtained by the conventional handmade procedures.Al Hamad et al., 2019 [32]Prospective controlled clinical trialCEREC OmnicamPVS impressionsCrowns seated using silicone and finger pressure. Replica technique used and gaps analysed using a stereomicroscope at 30× magnification.Marginal fit Ceramic crowns, which were made using all-digital approach or cast digitization by a laboratory or intra-oral scanner had comparable fit to those produced by conventional approach.Elrashid et al., 2019 [33]In vitro. studyLaboratory scanner Exocad smart optical 3D-scannerPVS impressionsCrowns held on to the die using a custom made holder with a pin. Marginal gap measured using a digital microscope at 50× magnification. Marginal fitLithium disilicate all ceramic crowns fabricated by using CAD-CAM techniques showed lesser marginal gap and better marginal fit compared to the conventional technique.Gudugunta et al., 2019 [34]In vitro studyCEREC scannerPVS impressionsThe crowns were held on to the dies using try in paste. The marginal gap was measured using a microscope camera at 200× magnification. Marginal fit Although there was a statistically significant difference between the two groups, marginal gap of both the groups were in clinically acceptable levels.Ahn et al., 2020 [35]Prospective controlled clinical trialCEREC Bluecam, EZIS PO and TRIOS 3 scannersComparison with other intra-oral scannersCrowns seated using silicone and finger pressure. Silicone replica technique used measured using a microscope at 100× magnification.Marginal fit The lithium disilicate crowns of all groups showed clinically acceptable fit.Kwong and Dudley, 2020 [36]In vitro studyTRIOS 3 and E4D scannerComparison with other intra-oral scanners Crowns seated using silicone and finger pressure. Digital stereomicroscopy with a camera at a magnification range of 2–18×. Three measurements were taken at each of the 4 locations Marginal fitThere was no difference in the marginal gaps of CAD/CAM lithium disilicate crowns constructed using two different intra-oral scanners of different generations.Lee, Son and Lee, 2020 [37]Prospective controlled clinical trialEZIS PO, i500, and CS3600 scannersPVS impressionsSilicone replica technique measured at 60× magnificationMarginal and internal fit There was a significant difference in the marginal and internal fit of the ceramic crowns fabricated using three intra-oral scanner types and one desktop scanner typeFerrairo et al., 2021 [38]In vitro studyCERAMILL, CEREC, EDG and Zirkonzahn scannersComparison with other intra-oral scannersCrowns seated on to dies using silicone. Silicone replica technique used. internal space measured using μ-CT and replica technique images by a film thickness images were captured by means of a stereomicroscope at 50× magnification.Marginal and internal fit The 4 systems are capable to produce restorations adapted within clinically appropriate levels.