Extraoral Scanner Research Articles

Comparison of intraoral and extraoral scanners for volumetric assessment before and after caries removal by the ICDAS score: a quantitative analysis.

Aimed to compare the volumetric calculations (VC) of intra-and-extraoral scanners on carious teeth before/after caries removal. 120 extracted human molars with ICDAS scores of 3, 4, and 5 were included. The teeth were scanned using an extraoral scanner (Ineos-X5, Dentsply Sirona) and three intraoral scanners (IOS) (iTero Element-5D, Align Technology; Primescan, Dentsply Sirona; Trios 4, 3Shape) before-and-after caries removal (CR). Eight Standard Tessellation Language (STL) data of each tooth sample were overlapped in Meshmixer (Autodesk) software for VC. Shapiro-Wilk, Paired Two-Sample T-test, repeated analysis of variance test statistics, and intraclass correlation coefficient (ICC) were used (p < 0.05). In initial VC, a significant difference observed between Ineos-X5 and iTero Element-5D (p < 0.001) and Ineos-X5 and Primescan (p < 0.001), regardless of the ICDAS score. No significant difference observed after CR between Ineos-X5 and iTero Element-5D (p = 0.917), Ineos-X5 and Primescan (p = 0.936), and Ineos-X5 and Trios 4 (p = 0.727) respectively. There was also no difference between the three IOS after CR (p ≥ 0.05), whereas the iTero Element-5D scanner significantly calculated less volume than Primescan and Trios-4 initially (p = 0.003). Maximum ICC was observed between the Ineos-X5 and Primescan in the ICDAS 5 score, before CR (ICC = 1, p < 0.001) and triple comparisons of iTero Element-5D, Primescan, and Trios-4 (ICC = 1, p < 0.001). Carious and irregular surfaces might affect the data collection of IOS. Intra-and-extraoral data may present negligible differences in the volumetric calculation, depending on the caries status and anatomical properties. These differences and factors may be important for future artificial intelligence networks that simulate the aftermath of caries removal. The IOSs tested in the current study can successfully collect data from irregular, deep and shallow cavities after caries removal.

Reliability of Extraoral Scanners in Capturing 3D Geometry for Dental Prostheses: A Systematic Review

Reliability of Extraoral Scanners in Capturing 3D Geometry for Dental Prostheses: A Systematic Review

Accuracy of the Conventional Facial Impression Method and Three-Dimensional Auricular Shape Data Obtained Using Extra- and Intraoral Optical Scanners

Background: Facial impression methods have been used to fabricate auricular prostheses; however, deformation due to the weight of the impression material remains. This study aimed to investigate the accuracy of auricular three-dimensional (3D) data obtained using a 3D optical extraoral scanner and an intraoral scanner compared with that of a conventional facial impression method. Methods: Six auricles were digitized using an extraoral scanner with and without a reference board around the auricle and an intraoral scanner. Auricle casts fabricated using auricle impressions were scanned using a laboratory scanner. All obtained data were superimposed, and the 3D deformations of the different methods were evaluated using measurement mapping and root mean square (RMS) values. The length, width, and height of the auricular casts and scanned data were measured and compared with the sizes of the original auricles measured using a caliper. Results: Large displacements of the back and margins of the ears were observed, and the RMS values ranged from 0.5–2.4 mm. Larger widths and smaller heights of the scanned and impression data were observed compared to the anthropometric ear data. Conclusions: The study concluded that the fabrication of auricular prostheses using optical scanning is clinically acceptable. All examined scanning techniques demonstrated discrepancies within acceptable limits when compared to the conventional facial impression method.

Accuracy of One-Piece vs. Segmented Three-Dimensional Printed Transfer Trays for Indirect Bracket Placement

Objective: To assess the accuracy of three-dimensional (3D) printed one-piece vs. multiple segmented transfer trays for indirect bonding techniques in moderate and severe crowding cases. Methods: Eighty digital maxillary dental models were produced by an extraoral scanner. 3D-printed one-piece and segmented trays were virtually designed utilizing Maestro 3D Ortho Studio® v4 and printed using a NextDent printer. The sample was classified into two groups: Group 1 (moderate crowding) included 40 digital models with a space deficiency of 6–7 mm, and Group 2 (severe crowding) included 40 digital models with a space deficiency of 10 mm. Ortho classic brackets were then placed into the 3D printed models with the aid of the transfer trays, and the models with the final bracket positioning were scanned using iTero scanner. Four measurements were selected on each tooth to perform the analysis. Mann–Whitney and Kruskal–Wallis tests were used for comparisons. A p-value of ≤ 0.05 was considered statistically significant. Results: In the moderate crowding group, statistically significant differences were detected between the one-piece, segmented, and control groups for three measurements (p &lt; 0.001), while the rest of the measurements showed no significant differences (p &gt; 0.05). In the severe crowding group, no significant differences were detected for any of the measurements. Conclusions: One-piece and segmented 3D-printed transfer trays are considered accurate tools for indirect bonding in moderate and severe malocclusion cases. The severity of crowding did not affect the accuracy of bracket transfer in indirect bonding.

A comparative quantitative assessment of 3D-printed PEKK and PEEK thin meshes in customized alveolar bone augmentation

ObjectiveCustomized nonabsorbable membranes are widely used in severe alveolar bone defects and provide sufficient and precise regenerated bone tissue for subsequent dental implant placement. Although 3D-printed polyetheretherketone (PEEK) meshes have confirmed successful use in clinical cases, the performance of a PEEK mesh is not satisfactory. Compared with PEEK, polyetherketoneketone (PEKK) has better mechanical and processing properties. However, whether PEKK is suitable for making customized membranes remains unclear. The objectives of this study were (1) to evaluate the printing precision, surface characteristics, mechanical characteristics and biocompatibility of the PEKK mesh and (2) to compare the properties of the PEKK and PEEK meshes.Materials and methodsBoth PEKK and PEEK meshes were designed and manufactured via additive manufacturing technology combined with computer-aided design (CAD). The printing precision was evaluated with a high-resolution extraoral scanner. The surface characteristics were evaluated with a contact angle system and three-dimensional optical microscopy. The mechanical characteristics were evaluated via three-point bending tests and tensile tests. The biocompatibility was evaluated with a CCK-8 assay, live/dead viability assay and qRT-PCT.ResultsCompared with the PEEK mesh, the PEKK mesh exhibited better control in terms of the thickness and aperture area. Both the PEKK mesh and the PEEK mesh had a hydrophobic surface, but the PEKK mesh had a smoother surface. Compared with the PEEK mesh, the PEKK mesh has better compression and tensile properties. Both the PEKK mesh and the PEEK mesh had good biocompatibility. The proliferation of cells on the PEKK mesh was slightly lower than that on the PEEK mesh.ConclusionsCompared with PEEK mesh, PEKK mesh has greater printing accuracy, smoother surfaces, better mechanical properties and similar biocompatibility and is expected to be used in the production of customized barrier membranes for the augmentation of severe bone defects. To ensure the stability of the mesh for clinical application, it is best to control the aperture diameter of the PEKK mesh to less than 2 mm with a thickness of 0.2 μm.

The Adoption and Impact of Dental Scanners in Dental Clinics across Punjab, India: Need of the Hour - A Questionnaire Study

Background: The aim of this article was to determine the adoption and impact of dental scanners in dental clinics across Punjab, India. Materials and Methods: A questionnaire was distributed via Google Forms to 450 dental clinics to gather data on the usage, benefits, and challenges associated with dental scanners. The findings highlight the growing trend of digital dentistry and its implications for clinical practice. Results: The survey conducted across 450 clinics in Punjab revealed that 60% of clinics do not use dental scanners, highlighting a significant gap in the adoption of this technology. Among the 40% of clinics that do use dental scanners, 25% utilize intraoral scanners, 10% use extraoral scanners, and 5% employ both types. The majority of these clinics have adopted dental scanners relatively recently, with only a small percentage using them for more than five years. Conclusion: Intra Oral Scanner (IOS) system is less time consuming when compared with other conventional methods. In terms of patient benefits, it reduces pain and discomfort. Ease of communicating with patients and educate them by providing video presentations before delivering any appliance or prostheses. Advanced technology is reshaping the future of digital dentistry, not only in orthodontics but also in other fields of dentistry as well.

An innovative evaluation method for clinical comparative analysis of occlusal contact regions obtained via intraoral scanning and conventional impression procedures: a clinical trial

ObjectivesTo compare the occlusal contact regions (OCRs) obtained through an intraoral scanning system and conventional impression procedures via an innovative evaluation method.Materials and methodsFifteen participants with complete dentitions and stable centric occlusion were included. Three groups were created based on the technique used to obtain the OCRs of quadrant posterior teeth at the maximal intercuspal position: 100 μm articulating paper (Control), an intraoral scanner (Test 1, T1) and conventional impression procedure (Test 2, T2). OCRs of control group were digitized by the intraoral scanner, while all conventional impressions were cast and digitized by an extraoral scanner. The virtual occlusal records of the 2 test groups were obtained by buccal bite registration. The OCRs within 100 μm in the 3 groups were three-dimensionally superimposed based on the tooth surfaces and the area of OCRs (SC, ST1, ST2) was calculated. The area of overlapping OCRs (SO) between the test groups and the control group was calculated. In the two test groups, the consistency rate of OCRs (SO/SC) and the positive rate of OCRs (SO/ST) were calculated and compared. For occlusal tightness evaluation, the mean occlusal clearances (OC) as well as minimum OC between the upper and lower models were calculated and compared.ResultsThe consistency rate of OCRs was 0.73 ± 0.17 for T1 group and 0.23 ± 0.13 for T2 group (p < 0.001). The positive rate of OCRs was 0.67 ± 0.15 for T1 group and 0.56 ± 0.23 for T2 group (p = 0.143). The mean OC was 51.32 ± 16.04 μm for T1 group and 68.20 ± 18.15 μm for T2 group (p = 0.024). The minimum OC was − 61.74 ± 35.38 μm for T1 group and 4.09 ± 27.15 μm for T2 group (p < 0.001).ConclusionsFor obtaining occlusal records in the quadrant posterior region, the tested intraoral scanning system was more reliable for recording occlusal contact regions and showed higher occlusal tightness compared with conventional impression procedures.Clinical relevance(1) The evaluation method can assist clinicians in making more objective analysis and comparisons among different sources of virtual occlusal records. (2) Occlusal tightness is a key and indispensable indicator in the evaluation of virtual occlusal records, and it can be quantified by measuring the occlusal clearance utilizing the current evaluation method.

Accuracy of measurements on CBCT-generated digital models using different exposure parameters (in vitro study).

Dental imaging comprises a wide range of techniques and modalities, each with different diagnostic features influenced by numerous parameters, all of which contribute to the precision and effectiveness of dental evaluations and treatments. This study examined the dimensional reproducibility of arch measurements from CBCT scans with different voxel sizes and exposure parameters compared to a reference model from Extra-oral scanners (EOS) and how these parameters affected digital matching and diagnostic image quality. A diagnostic observational study of arch dimensions, including inter-canine, inter-premolar, intermolar, arch width and arch length, was conducted on digital models (DMs) created from 65 CBCT scans of a full dentate epoxy maxillary model. The measurements obtained from EOS scans served as the control for the study. Normality was tested with the Shapiro-Wilk test, comparisons used the Kruskal-Wallis test with Bonferroni-adjusted pairwise comparisons for significant results, and data were analysed using IBM SPSS (Version 26.0), with significance set at p < .05. Significant deviations were revealed among study groups, with group I (smallest voxel size) consistently displaying the lowest values, mean (SD) deviation was reported as 0.01 (0.006) and group IV (lowest kV value) exhibiting the highest deviations, mean (SD) deviation of 0.16 (0.17). Combining a small voxel size (0.12 mm) with high milliampere (8 mA) and kilovoltage (90 kV) settings in CBCT ensured detailed anatomical visualization and accurate linear measurements, crucial for precise dental assessments, and emphasizing the necessity for strict control over CBCT parameters in dental applications.

A Comparative Evaluation of the Accuracy between the Extraoral Scanner (Rainbow) and Intraoral Scanner (Medit I500) Digital Impressions in Vitro

A Comparative Evaluation of the Accuracy between the Extraoral Scanner (Rainbow) and Intraoral Scanner (Medit I500) Digital Impressions in Vitro

A Comparative Evaluation of the Accuracy between the Extraoral Scanner (Rainbow) and Intraoral Scanner (Medit I500) Digital Impressions in Vitro

A Comparative Evaluation of the Accuracy between the Extraoral Scanner (Rainbow) and Intraoral Scanner (Medit I500) Digital Impressions in Vitro

Effect of the scanner type on the marginal gap and internal fit of two monolithic CAD/CAM esthetic crown materials: An in vitro study.

The durability of indirect restorations is significantly influenced by marginal adaptation and internal fit. The use of computer-aided design/computer-aided manufacturing (CAD/CAM) with digital impressions has reduced dental prosthesis fabrication errors, improving the long-term survivability of the restorations. The present study assessed the impact of intraoral and extraoral scanning methods on the marginal adaptation and internal fit of 2 different types of monolithic crowns manufactured using CAD/CAM. A total of 40 three-dimensional (3D) resin-printed dies were randomly assigned to 2 groups based on the type of crown material (n = 20 per group). Each group was divided into 2 subgroups (n = 10 per group) according to the die-scanning technique: subgroup A, scanned using the intraoral scanner (IOS) Primescan; and subgroup B, scanned using the extraoral scanner (EOS) inEos X5. The digitized photos were converted into a 3D virtual crown design using CAD software. The internal discrepancy values, and the marginal gap between the 3D resin-printed die and the crown were assessed using a ×50 digital microscope. The data was checked for normality with the Kolmogorov-Smirnov test, and the Mann-Whitney U test was used to compare the tested groups. The collected data was analyzed at a significance level set at p < 0.05. The different scanning techniques used had a statistically significant effect on the vertical marginal gap and the internal fit [μm] (p < 0.05). As far as the crown materials are concerned, BRILLIANT Crios showed a significantly higher marginal gap as compared to Tetric CAD when scanned with inEos X5 (p = 0.004), whereas the differences were insignificant with regard to the internal fit (p > 0.05).The crown parameters tested with both scanning systems were within the clinically acceptable ranges. Scanning methods and crown materials had an impact on the internal fit and vertical marginal gap of monolithic crowns.

Custom made orbital prosthesis using digital approach: A case report

Factors that affect a person's quality of life can be influenced by aesthetics. In the case of involving orbits, it is a big problem in aesthetic factors and must be done immediately so as not to affect the quality of life of a person. A 76-year-old male patient came to the prosthodontic dental and oral hospital on a referral from an ophthalmologist to have an eye prosthesis because he wanted to improve his appearance. The patient wants to have an eye prosthesis immediately because of embarrassment. The creation of an eye prosthesis by printing with extraoral scans and orbital contour design is the treatment plan given to the patient. After that, the first visit to the orbital socket is scanned, the color of the eye is selected and the patient can go home. The contour of the orbit of the eye can be designed with 3D software and 3D printed for the working model, as well as the search for a suitable stock eye for the patient. The next visit can be done by selecting colors and trying them out. This speeds up visits, prosthetic comfort and aesthetics.

3D teeth micromovements with DIC technique and novel extraoral scanner

3D teeth micromovements with DIC technique and novel extraoral scanner

Intraoral and Extraoral Scanning Technologies in the Digital Workflow Era: An Integrative Review with Artificial Intelligence

Intraoral and Extraoral Scanning Technologies in the Digital Workflow Era: An Integrative Review with Artificial Intelligence

Trueness of Extraoral Digital Impressions for Full-Arch Implant Impressions-In Vitro Study.

Direct scanning of silicone impressions is a valid technique. However, studies in implant-supported rehabilitations are lacking. This in vitro study aims to compare the trueness of impressions obtained with two types of silicone and their corresponding stone casts, using two laboratory scanners in a full-arch implant rehabilitation. A master cast with six dental implants was scanned with a 12-megapixel scanner to obtain a digital master cast. Ten implant impressions were made using two silicones (Zhermack and Coltene) with the open-tray technique. The impressions and stone casts were scanned by two extraoral scanners (Identica T500, Medit; and S600 ARTI, Zirkonzhan). Trueness was assessed by comparing linear and angular distances in digital casts with the master cast. A p < 0.05 significance level was considered. The results showed that for the linear measurements, 72% were higher than the master cast measurements, and no consistent pattern was observed in the angular measurements. The greatest deviations were detected between the most posterior implants, with mean values ranging between 173 and 314 µm. No significant differences were found between scanners. However, differences were observed in the distances between silicones (46.7%) and between impressions and stone casts (73.3%). This work demonstrates that the direct scanning of silicone impressions yields results comparable to those obtained from scanning gypsum casts in full-arch implant-supported rehabilitation.

In Vitro Analysis of the Accuracy of the Use of Waste Zirconia Dust Compared With Optical Scanning Spray on Implant Abutment Models in Extraoral Scanning Protocol.

Introduction The evolution of computer-aided design/computer-aided manufacturing(CAD/CAM) systems has heightened the significance of digital models in dentistry, particularly for fabricating prostheses like inlays, crowns, and bridges. While digital dentistry offers enhanced speed and precision, the initial investment in intraoral scanners may pose a barrier for some clinicians. Extraoral or lab scanners, however, offer a viable alternative, reducing laboratory time and providing accurate prostheses fit, though challenges such as reflective surfaces and availability of scanning sprays persist, impacting scanning quality and operator technique. Optical scanning using laboratory scanners is a routine practice in today's age of digital dentistry. Often these require powder opacification to record fine details. There arenumbered studies on the accuracy of scanning sprays. Materials and methods Tencasts, poured with type 4 dental stone (Elite Rock, Zhermack, Italy) with single implants, were used for the purpose of this study. Each cast was scanned by two different operators, using both mediums. It was scanned using an extraoral scanner (E4, 3Shape, Copenhagen,Denmark). Operator A used easy scan (Alphadent, Korea), followed by zirconia dust (Upcera, Guangdong, China), whereas operator B used zirconia dust first. Digital models within each group were superimposed individually to measure precision. Results Easy scan operator 1 and zirconia dust operator 1 differ by 0.16000 (p = 0.0802). In scenario 2, easy scan operator 2 and zirconia dust operator 2 differ by 0.21900 (p = 0.0212) . Operator type significantly affects performance, emphasizing the need to account for operator variability in relevant contexts. The trueness values obtained for zirconia dust and easy scan among both operators were statistically insignificant. Conclusion Zirconia dust can be reliably used for extraoral scanning of abutments in place of optical scanning sprays.

The internal and marginal adaptation of lithium disilicate endocrowns fabricated using intra and extraoral scanners: An in-vitro study.

The impression technique highly influences the adaptation of ceramic restorations. Not enough information is available to compare the marginal (MF) and internal fit (IF) of endocrowns fabricated with various digitization techniques. Therefore, this in-vitro study aimed to compare the MF and IF of lithium disilicate (LDS) endocrowns fabricated through direct and indirect digital scanning methods. One extracted maxillary molar was used to fabricate endocrowns. The digitization of the model was performed with (G1) direct scanning (n = 10) utilizing an intraoral scanner (IOS), (G2) indirectly scanning the conventional impression taken from the model using the same IOS (n = 10), (G3) indirectly digitalizing the obtained impression using an extraoral scanner (EOS) (n = 10), and (G4) scanning the poured cast using the same EOS (n = 10). The MF and IF of the endocrowns were measured using the replica method and a digital stereomicroscope. The Kruskal-Wallis test was used to analyze data. The studied groups differed significantly (p<0.001). G2 (130.31±7.87 μm) and G3 (48.43±19.14 μm) showed the largest and smallest mean vertical marginal gap, respectively. G2 and G3 led to the highest and lowest internal gaps in all regions, respectively. With significant differences among the internal regions (p<0.001), the pulpal area demonstrated the most considerable misfit in all groups. Scanning the impression using an extraoral scanner showed smaller marginal and internal gaps.

Evaluation of Three-Dimensional Digital Models Formulated From Direct Intra-oral Scanning of Dental Arches in Comparison With Extra-oral Scanning of Poured Dental Models in Terms of Dimensional Accuracy and Reliability.

The study's objective was to assess the dimensional accuracy and reliability of dental digital models prepared by direct intraoral scanning and indirect scanning of the plaster models compared to the plaster models as the gold standard. This study included 20 patients. Nine had a class I malocclusion, seven had a class II malocclusion, and four had a class III malocclusion. Intraoral scanning was done for the upper and lower arches of all the patients enrolled in this study using an intraoral scanner (i700; Medit, Seoul, Korea). The next step was preparing the plaster model for the control group. Addition-silicone impressions were taken for each patient's arches. The impressions were poured according to American Board of Orthodontics (ABO) standards. Finally, the digital models of the indirect scanning group were prepared using a 3D desktop scanner (T710; Medit). In total, 26 measurements were made on the plaster and digital models. Paired t-tests were used to test for significant differences between the studied groups. The reliability of the studied techniques was tested using intraclass correlation coefficients (ICCs). Because of the multiple comparisons, the ɑ level was adjusted and set at 0.002. No significant differences were found between the intraoral scanning group (20 patients) and the plaster models group (20 patients; P>0.002). The ICCs ranged from 0.814 to 0.993, indicating excellent agreement between the direct digital and traditional plaster models. There were no significant differences between the digital and original plaster models (P>0.002). ICCs ranged from 0.834 to 0.995, indicating excellent agreement between the indirect digital and original plaster models. No significant differences were detected between the direct and indirect digital models (P>0.002). ICCs ranged between 0.813 and 0.999, indicating excellent agreement between direct and indirect digital models. Both direct and indirect scanning techniques are accurate and reliable for digital model preparation and can be considered an alternative to traditional plaster models used in clinical orthodontics diagnostic applications. The intraoral scanning technique can be considered a valid alternative for indirect scanning of the plaster models to prepare digital working models during the digital design and fabrication of orthodontic appliances such as clear aligners.

Comparative Accuracy of Intraoral and Extraoral Digital Workflows for Short Span Implant Supported Fixed Partial Denture Fabrication: An In Vitro Study.

BACKGROUND The advent of digital impressions using computer-aided design and manufacturing technology (CAD/CAM) has simplified and improved the fabrication of implant prostheses in dentistry. The conventional impression has several drawbacks, including tray selection, material type, impression technique, impression disinfection, and cast model storage. The inaccuracies caused by distortion and contraction of impression material can be minimized with digital impressions. This study aimed to compare digital dental impressions of 10 working casts made using the Pindex laser removable die system to fabricate parallel drill channels vs 10 working casts made using the Di-Lok plastic tray removable die system. MATERIAL AND METHODS An implant master die with 2 dental implant analogs was fabricated. Ten working casts using the Pindex laser removable die system with parallel drill channels and 10 working casts using the Di-Lok plastic tray removable die system were fabricated. The working casts were scanned using an extra-oral laboratory scanner and the implant master model was scanned with an intra-oral scanner. RESULTS The properties of the casts made using the 2 systems were evaluated and analyzed with ANOVA and post hoc Tukey test. The mean horizontal linear distances between A1B1 (P<0.021), A2B2 (P<0.018), C1D1 (P<0.026), C2D2 (P<0.03), B1C1 (P<0.01), and mean vertical distances between B1A2 (P<0.015), C1D2 (P<0.001), B1B2 (P<0.028), and C1C2 (P<0.001) were significantly different between the Pindex system and Di-Lok tray system as compared to intra-oral scans. CONCLUSIONS Complete digital workflow with intra-oral scans were more than the partial digital workflow with extra-oral scans for the Pindex system and Di-Lok tray systems.

Accuracy of Silicone Impressions and Stone Models Using Two Laboratory Scanners: A 3D Evaluation.

To evaluate the in vitro accuracy of impressions obtained with two silicone and corresponding stone models using two laboratory scanners. A master model with synthetic resin teeth with two single-unit crown preparations was created and scanned using a 12-megapixel scanner. Five conventional impressions of the physical model were prepared with different silicone impression systems (Zhermack and Coltene) using the double-mix technique and poured with gypsum. The impressions and stone models obtained were scanned using two extraoral scanning systems (Identica T500, Medit; S600 ARTI, Zirkonzahn). All best-fit superimpositions of the teeth areas were conducted between the master model and the scans of the impressions and models obtained with the two scanners. A P < .05 level was considered significant. The Identica T500 Medit scanner showed an accuracy of 102.34 (89.67, 115.01) μm for Coltene silicone and 79.51 (67.82, 91.21) μm for Zhermack silicone, while the S600 ARTI Zirkonzhan scanner presented 110.79 (98.24, 123.33) μm and 91.91 (81.29, 102.54) μm, respectively, with significant differences between scanners for Zhermack silicone (P = .008) and for the corresponding stone models (P = .002). Zhermack silicone presented overall discrepancies lower than Coltene silicone, with statistically significant differences in both scanners analyzed (P < .001; P = .017). However, the discrepancies found were within clinically acceptable values. With the Zirkonzahn scanner, discrepancies found in the Zhermack impressions were lower than in the corresponding stone models (P < .001). The direct digitization of silicone impressions with laboratory scanners presented comparable results to conventional techniques with stone models.