The trueness of an intraoral scanner in scanning different post space depths.

OBJECTIVES: The purpose of this in vitro study was to evaluate the trueness of scanning the post space up to 20 mm with an intraoral scanner (IOS). METHODS: We captured 20-, 18-, 16-, 14-, 12-, and 10-mm length post space scans using an IOS (Primescan) eight times each by shortening the apical 2 mm end of the same mandibular canine tooth. The reference impressions of each length group were taken using a light-body polyvinyl siloxane impression material and were scanned with an extraoral scanner. The recorded standard tessellation language (STL) data of all impressions were uploaded to a 3D matching program for the trueness evaluation via the root mean square (RMS) calculation. For the statistical analysis, the Kruskal-Wallis and post-hoc Mann-Whitney U nonparametric tests were performed to compare the differences among the groups (α=0.05). RESULTS: The median RMS values increased in direct proportion to the length of the post space from 10 mm (357.1 µm) to 20 mm (897.5 µm). We noted a significant difference among groups (p< 0.001). In the pairwise comparisons, there were no significant differences between the 14 mm and 16 mm groups (p=0.431) or between the 18 mm and 20 mm groups (p=0.036), while other paired groups showed significant differences (p=0.001). CONCLUSIONS: The scanned space depth affected the trueness of the IOS (Primescan). If the post depth was below 14 mm, and the minimum diameter was 2.2 mm, Primescan could be used for impressions of the post-core structure, simplifying the impression procedure. CLINICAL SIGNIFICANCE: IOS seems to be a promising technology for taking digital impressions of post spaces, but cannot be recommended as a routine procedure at its present stage, as final results are highly dependent on the clinical situation. Further studies with different IOS systems are needed to gain sound evidence.

Comparison of Reliability of 3 Resonance Frequency Analysis Devices: An In Vitro Study.

The purpose of the present study was to investigate the intraobserver and interobserver reliability of 3 resonance frequency analysis (RFA) devices and to compare the implant stability quotient (ISQ) values according to implant macro design and diameter in 2 different bone densities. A total of 64 implants (Neoss ProActive; Neoss; Harrogate, UK) of varying diameters (3.5 and 4.0 mm) and implant macro design (tapered and straight) were placed in 2 artificial bone blocks (the density of type 2 and 3). The implant primary stability was measured using Osstell IDx (Osstell; Göteborg, Sweden), Osstell Beacon and Penguin RFA (Integration Diagnostics; Göteborg, Sweden). The ISQ value of each implant was measured by 2 observers and recorded 5 times in 2 directions. The intraobserver and interobserver reliability of RFA devices were evaluated. In addition to that, mean ISQ values were calculated for each RFA device to evaluate the effect of implant diameter, implant macro design, and bone density on ISQ values. ISQ values were significantly higher for implants placed within the type 2 bone than for the type 3 bone. The 4.0-mm diameter implants presented higher ISQ values than 3.5-mm diameter implants. The intraclass correlation coefficient (ICC) values for intraobserver reliability were above 0.85 for each observer and the ICC values for interobserver reliability were 0.94, 0.93, and 0.98 for Osstell IDx, Osstell Beacon, and Penguin RFA, respectively. Although there was excellent interobserver reliability with 3 RFA devices, the intraobserver reliability of Osstell Beacon and Penguin RFA were slightly better than Osstell IDx. Bone density and implant diameter were parameters affecting the primary stability of implants.

Accuracy of six intraoral scanners for scanning complete-arch and 4-unit fixed partial dentures: An in vitro study.

STATEMENT OF PROBLEM: The digital scan accuracy of different intraoral scanners (IOSs) for long-span fixed prosthesis and the effect of the starting quadrant on accuracy is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of 6 IOSs for complete-arch and prepared teeth digitally isolated from the complete-arch and to determine the effect of the starting quadrant on accuracy. MATERIAL AND METHODS: A maxillary model containing bilaterally prepared canines, first molar teeth, and edentulous spans between the prepared teeth was used. The model was scanned by using a highly accurate industrial scanner to create a digital reference data set. Six IOSs were evaluated: TRIOS, iTero, Planmeca Emerald, Cerec Omnicam, Primescan, and Virtuo Vivo. The model was scanned 10 times with each IOS by 1 operator according to the protocols described by the manufacturers. Five scans were made starting from the right quadrant (ScanR), followed by 5 scans starting from the left quadrant (ScanL). All data sets were obtained in standard tessellation language (STL) file format and were used to evaluate accuracy (trueness and precision) with a 3D analyzing software program (Geomagic Studio 12; 3D Systems) by using a best-fit alignment. The prepared teeth were digitally isolated from the complete-arch and evaluated with the analyzing software program. The Kruskal-Wallis and Mann-Whitney U statistical tests were used to detect differences for trueness and precision (α=.05). RESULTS: Statistically significant differences were found regarding IOSs (P<.003) and scanning sequence (P<.05). The TRIOS showed the best trueness for the complete-arch, but not statistically different from Primescan, Virtuo Vivo, and iTero (P>.003). The lowest median values for precision of the complete-arch were also found using TRIOS, but no significant difference was found among the scanners (P>.003). In terms of trueness and precision, Primescan had the best accuracy for preparations. Emerald showed significant differences depending on the scanning sequence for complete-arch accuracy. ScanR for trueness (P=.021) and ScanL for precision (P=.004) showed improved results. However, Emerald, TRIOS, and Virtuo Vivo showed statistically significant differences in precision of preparations depending on scanning sequence. ScanL deviated less than ScanR when scanned with TRIOS (P=.025) and Emerald (P=.004), and the opposite with Virtuo Vivo (P=.008). In terms of preparations trueness, no significant difference was found between the ScanR and ScanL of any IOS (P>.05). CONCLUSIONS: Based on this in vitro study, the accuracy of the complete-arch and prepared teeth differed according to the IOS and scanning sequence.

Effect of different composite materials used as core build-ups on the trueness of intraoral scanning.

PURPOSE: To evaluate the trueness of digital impressions of different composite resin materials that can be used for core build-ups in clinical practice. MATERIALS AND METHODS: A maxillary central incisor was prepared and scanned with an intraoral scanner (Primescan, Dentsply Sirona). Ten composite resin specimens (in three groups: universal composite; flowable composite; and bulk fill resin composite) were milled in the same dimensions of the prepared tooth and scanned. The data of the prepared tooth were used as reference, and the data obtained from the composite resin specimens were aligned with the evaluation software (Geomagic Studio 12) to determine deviation values. Kruskal-Wallis with Dunn post hoc test was performed (α = .05). RESULTS: There were significant differences in the trueness of digital impressions between some composite resin groups (P < .05). The mean trueness deviation values were in the range of 12.75 µ m (G-aenial Posterior) to 17.06 µ m (Filtek Bulk Fill Posterior). The trueness of G-aenial Posterior (12.75 µ m) was higher than that of Core-X Flow (14.62 µ m), Clearfil Majesty Flow (16.93 µ m), and Filtek Bulk Fill Posterior (17.06 µ m). Filtek Bulk Fill Posterior exhibited lower trueness than Clearfil Majesty Esthetic (12.93 µ m), Clearfil Majesty Posterior (13.50 µ m), and Charisma Classic (13.81 µ m). CONCLUSION: Different composite resins used for core build-up can impact the trueness of digital impressions, with universal composite resin scans being the truest compared to flowable and bulk fill composite resin scans. All scanned substrate groups can be regarded as within a clinically acceptable range.

Accuracy of Digital Impressions Obtained Using Six Intraoral Scanners in Partially Edentulous Dentitions and the Effect of Scanning Sequence.

PURPOSE: To compare the accuracy of six intraoral scanners in two different partially edentulous maxillary models and to evaluate the effect of scanning sequence on accuracy. MATERIALS AND METHODS: Maxillary Kennedy Class I and Class IV situations were used as reference models. The reference datasets were obtained by scanning the models using a highly accurate industrial scanner (ATOS Core 80, GOM). The following six intraoral scanners were evaluated: Trios 3 (3Shape), iTero Element 2 (Align Technology), Emerald (Planmeca), CEREC Omnicam (Dentsply Sirona), CEREC Primescan (Dentsply Sirona), and Virtuo Vivo (Dental Wings). A total of 120 scans from both models were obtained using the six intraoral scanners and divided into two groups based on scanning sequence. Accuracy was evaluated by deviation analysis using 3D image processing software (Geomagic Studio 12, 3D Systems). Kruskal Wallis and Mann-Whitney U tests were performed (P ≤ .05) for statistical analysis. RESULTS: There were significant differences in the accuracy of digital impressions among intraoral scanners and scanning sequences. The trueness of the Trios scanner and the precision of the Trios, Primescan, and iTero scanners were significantly higher than for the other scanners. The Emerald had the lowest accuracy among the six intraoral scanners tested. Accuracy was affected by scanning sequence when using the Virtuo Vivo, Emerald, Primescan, and iTero. CONCLUSION: In Kennedy Class I and Class IV partially edentulous cases, it is useful to consider that the intraoral scanner used may affect the accuracy of the digital impression.

Comparing the accuracy of six intraoral scanners on prepared teeth and effect of scanning sequence.

PURPOSE: The aim of this study was to evaluate the accuracy of six recently introduced intraoral scanners (IOSs) for single crown preparations isolated from the complete arch, and to determine the effect of scanning sequence on accuracy. MATERIALS AND METHODS: A complete arch with right and left canine preparations for single crowns was used as a study model. The reference dataset was obtained by scanning the complete arch using a highly accurate industrial scanner (ATOS Core 80, GOM GmbH). Six different IOSs (Trios, iTero, Planmeca Emerald, Cerec Omnicam, Primescan, and Virtuo Vivo) were used to scan the model ten times each. The scans performed with each IOS were divided into two groups, based on whether the scanning sequence started from the right or left quadrant (n=5). The accuracy of digital impression was evaluated using three-dimensional analyzing software (Geomagic Studio 12, 3D Systems). The Kruskal Wallis and Mann-Whitney U statistical tests for trueness analysis and the One-way ANOVA test for precision analysis were performed (α=.05). RESULTS: The trueness and precision values were the lowest with the Primescan (25 and 10 µm), followed by Trios (40.5 and 11 µm), Omnicam (41.5 µm and 18 µm), Virtuo Vivo (52 and 37 µm), iTero (70 and 12 µm) and Emerald (73.5 and 60 µm). Regarding trueness, iTero showed more deviation when scanning started from the right (P=.009). CONCLUSION: The accuracy of digital impressions varied depending on the IOS and scanning sequence used. Primescan had the highest accuracy, while Emerald showed the most deviation in accuracy for single crown preparations.