Effect of novel prefabricated auxiliary devices attaching to scan bodies on the accuracy of intraoral scanning of complete-arch with multiple implants: An in-vitro study

Accuracy of complete arch nonsplinting and noncalibrated splinting implant scanning techniques recorded by using five intraoral scanners

STATEMENT OF PROBLEM

Splinting implant scan bodies (ISBs) has been reported to improve the accuracy of intraoral scanners (IOSs) compared with nonsplinting methods. However, the accuracy of commercially available horizontal noncalibrated ISBs remains unknown.

PURPOSE

The purpose of this in vitro study was to compare the accuracy of complete arch scans obtained using horizontal noncalibrated or standard ISBs recorded by using 5 different IOSs.

MATERIAL AND METHODS

An edentulous maxillary stone cast with 6 implant abutment analogs (MultiUnit Abutment Plus Replica) was used. The reference scan was obtained by digitizing the reference cast with a calibrated laboratory scanner (T710). Five groups were created based on the IOS tested: TRIOS 5, i700, Primescan, Aoralscan 3, and iTero. Two subgroups were defined based on the ISBs selected to record complete arch implant scans: standard ISBs (Stand subgroup) or horizontal noncalibrated ISBs (Apollo subgroup) (n=10). In the Stand subgroup, a standard ISB (Accurate Implant Body MUA) was positioned on each implant abutment, and experimental scans were captured. In the Apollo subgroup, a horizontal ISB (Apollo) was positioned on each implant abutment, connecting the implants horizontally following the arch shape. The standard tessellation language (STL) files of all the experimental scans were exported. A program (DentalCAD) was used to design a complete arch implant-supported bar from the control and each experimental scan. Then, another program (Geomagic) was used to perform linear and angular measurements of the implant interfaces of each bar. The measurements obtained in the control scan were used as a reference to measure the scanning distortion of each specimen. The 2-way ANOVA Welch and pairwise multiple comparison Tukey tests were used to analyze trueness (α=.05). The Levene and pairwise multiple comparison Wilcoxon rank tests were applied to analyze precision (α=.05).

RESULTS

Significant linear trueness differences were found between the subgroups (P<.001) with a significant interaction group×subgroup (P<.05). The iTero system demonstrated a significantly worse linear trueness compared with the other IOSs (P<.001). The TRIOS 5 obtained the worst linear precision. Significant angular trueness discrepancies were found between the groups (P<.001) and subgroups (P=.048) with a significant interaction group×subgroup (P=.041). The Apollo group obtained better angular trueness (P<.001) and precision (P<.001) compared with the Stand ISBs group.

CONCLUSIONS

Both the implant scanning technique and choice of IOS impacted the accuracy of complete arch implant scans.

Accuracy of a complete arch noncalibrated splinting implant scanning technique with a palatal orientation recorded by using different intraoral scanners

STATEMENT OF PROBLEM

The accuracy of noncalibrated splinting implant scanning techniques that include horizontal implant scan bodies (ISBs) positioned connecting the implants by following the shape of the dental arch have previously been analyzed. A novel horizontal ISB connected in the center of the arch has been introduced; however, the accuracy of this noncalibrated splinting implant scanning technique with a palatal orientation is unknown.

PURPOSE

The purpose of this in vitro study was to compare the accuracy of a nonsplinting and noncalibrated splinting implant scanning technique recorded using 5 intraoral scanners (IOSs).

MATERIAL AND METHODS

A laboratory scan (reference scan) of an edentulous stone cast with 6 implant abutment analogs (MultiUnit Abutment Plus Replica) was acquired (T710). Five groups were created based on the IOS tested: TRIOS5, Primescan, i700, Aoralscan3, and iTero Element 5D. Two subgroups were defined based on the implant scanning technique used to record complete arch implant scans: a nonsplinted (NS-ISB subgroup) or noncalibrated splinting (NCS-IOC group) implant scanning technique (n=10). In the NS-ISB subgroup, an ISB (TrueScan Body) was positioned on each implant abutment, and complete arch implant scans were recorded and exported in standard tessellation language (STL) format. In the NCS-IOC subgroup, a horizontal ISB (IOConnect) was positioned on each implant abutment connecting them in the center of the palate. Implant scans were recorded, capturing only the section of the horizontal ISBs located in the center of the arch. Then, the scans were processed by a specific program (TruSuite), and the STL of the scans were exported. A program (Geomagic) was used to perform linear and angular measurements among the ISBs in the control scan and each specimen. The measurements obtained in the control scan were used as a reference to measure the scanning distortion of each specimen. The 2-way ANOVA Welch and pairwise multiple comparison Tukey tests were used to analyze trueness (α=.05). The Levene and pairwise multiple comparison Wilcoxon rank tests were used to analyze precision (α=.05).

RESULTS

Linear trueness discrepancies were found among the groups (P<.001) and subgroups (P<.001), with a significant interaction group×subgroup (P=.002). The NCS-IOC group had significantly better linear trueness than the NS-ISB group. The TRIOS5, Primescan, and Aoralscan3 systems had significantly better linear trueness than the i700 device. The Levene test revealed that the NCS-IOC group had significantly better linear precision than the NS-ISB group. Additionally, angular trueness discrepancies were revealed among the groups (P<.001) and subgroups (P<.001), with a significant interaction group×subgroup (P<.001). The NCS-IOC group had significantly better angular trueness than the NS-ISB group. The i700 and Aoralscan3 systems had the best angular trueness. Additionally, the NCS-IOC group had significantly better angular precision than the NS-ISB group. The TRIOS5 and Aoralscan3 had the best angular precision.

CONCLUSIONS

The implant scanning technique used and IOS selected impacted the trueness and precision of complete arch implant scans.

Clinical precision of Aoralscan 3 and Emerald S on the palatal and dentition areas: Evaluation for forensic applications

OBJECTIVES

To compare the precision (repeatability and intermediate precision) of palatal and dentition scans taken with two different intraoral scanners.

METHODS

The maxillary arch of 23 individuals was scanned three times using the Aoralscan 3 (Shining 3D) and Emerald S (Planmeca), resulting in 6 scans per individual. The scans were segmented in Meshmixer into palatal and dentition areas. Each replicate of an individual was compared within the specific scanner (repeatability) and to the corresponding replicate of the other scanner (intermediate precision). The scans were aligned using the iterative closest-point algorithm in the Zeiss Inspect software. The mean absolute distance between the aligned surfaces was calculated. Statistical comparisons were made using Friedman's two-way analysis of variance. Data are presented in median (quartile 1; quartile 3) form.

RESULTS

No significant difference in repeatability was found between Emerald S and Aoralscan 3 for the palate (26 µm [22; 26] vs. 22 µm [18; 26]) and for dentition (37 µm [31; 44] vs. 38 µm [35; 48]. Intermediate precision of the palate (32 µm [26; 43]) and dentition (72 µm [63; 80]) was significantly lower than the repeatability of Emerald S (p < 0.05, p < 0.001) and of Aorlascan 3 (p < 0.001, p < 0.001). Both precision types of both scanners were significantly lower for the dentition than for the palate (p < 0.001).

CONCLUSION

The precision of the dentition scan is lower than that of the palate. The precision of the Aoralscan 3 is similar to that of the Emerald S scanner.

CLINICAL SIGNIFICANCE

Novel intraoral scanners could be used with high precision for palatal soft tissue scans, expanding their clinical utility. Aligning scans from two different IOSs still has high precision, facilitating the interchangeable use of intraoral scanners for orthodontic, prosthetic, and forensic examinations.

Classification of Complete-Arch Implant Scanning Techniques Recorded by Using Intraoral Scanners

OBJECTIVES

To classify the complete-arch implant scanning techniques recorded by using intraoral scanners (IOSs).

OVERVIEW

Different implant scanning techniques have been described for recording complete-arch implant scans by using IOSs. However, dental literature lacks on a classification of these implant scanning techniques. Implant scanning techniques aim is to record the 3-dimensional position of the implants being scanned, while implant scanning workflows require additional scans to record all the information needed for designing an implant prosthesis. This additional information includes soft tissue information, tooth position, antagonist arch, and maxillomandibular relationship.

CONCLUSIONS

There are five complete-arch implant scanning techniques captured by using IOSs: non-splinting, non-calibrated splinting, calibrated implant scan bodies, calibrated frameworks, and reverse impression methods. The digital workflow varies depending on the implant scanning technique selected.

CLINICAL SIGNIFICANCE

The understanding of the varying implant scanning techniques and the main differences among them may ease the decision criteria for recording digital implant scans by using intraoral scanners.

Effect of prefabricated auxiliary devices in different optical properties and shapes on the accuracy of intraoral scanning of the edentulous arch with multiple implants: An in-vitro study

OBJECTIVES

This study aimed to evaluate the impact of prefabricated auxiliary devices (PADs) in different optical properties and shapes on the accuracy of digital implant impressions.

METHODS

An edentulous maxillary all-on-4 master model was fabricated. PADs were 3D-printed in different resin materials (Grey, Translucent, White, Yellow) and shapes (Cuboid, Cylinder, Sphere) using a 3D printer (AccuFab-C1s, 3DShining, Hangzhou, China). The master model was digitalized using a dental laboratory scanner (D2000, 3Shape, Copenhagen, Denmark) 4 times as the reference models. Test models were obtained without (control group) or with PADs by an intraoral scanner (Aoralscan 3, Shining3D, Hangzhou, China) for ten repetitions of each group using the scanning pattern recommended by the manufacturer. The related files were imported into inspection software to assess Root Mean Square (RMS), linear and angular accuracy. Aligned Ranks Transformation ANOVA, Kruskal-Wallis and Mann-Whitney tests were used to evaluate the differences in these values. The level of significance was set at α=0.05.

RESULTS

PADs in different optical properties and shapes demonstrated accuracy enhancement to different extents depending on their combinations. The PADs in combinations of white-cuboid, grey-sphere and yellow-sphere demonstrated the optimal trueness enhancement. The Aligned Ranks Transformation ANOVA indicated that the optical properties of the PADs significantly influenced the RMS, linear and angular accuracy. The main effect of optical properties indicated that translucent PADs generally generated more deviations than the others. The shapes of the PADs significantly influenced the angular accuracy. The main effect of shapes indicated that cylinder resulted in lower angular trueness on YZ plane than cuboid (p = 0.006) and sphere (p < 0.001).

CONCLUSION

The optical properties and shapes of the PADs significantly influenced the scanning accuracy. Translucent PADs demonstrated more deviations than the others. Lower angular trueness on the YZ plane was seen in cylinder design compared to the others.

CLINICAL SIGNIFICANCE

The optical properties and shapes of prefabricated auxiliary devices should be critically considered to optimize the scanning accuracy. Prefabricated auxiliary devices in translucent optical properties and cylinder shape should be avoided.

Influence of the color of 3D-printed scan aids on the trueness of complete arch digital scans

PURPOSE

To determine the influence of using 3D-printed scan aids in varying colors on the trueness of digital scans.

MATERIALS AND METHODS

A master cast with five multi-unit analogues was scanned. The acquired dataset was exported to standard tessellation language (STL) file format to serve as the reference STL. 3D printing of the prototype in five distinct colors (beige [SABEIGE], grey [SAGREY], white [SAWHITE], red [SARED], and blue [SABLUE]) of polylactic acid filament was executed. The experimental STLs of each color group were aligned to the reference STL. RMS values were solely computed for the scan bodies. Based on the centers of the created best-fit and offset planes, scan bodies were converted into virtual cylinders. Cartesian coordinates of each cylinder were acquired. Subsequently, angular (AD) and linear deviation (LD) values were calculated. LD was further examined separately along the x, y, and z axes. Data were statistically analyzed.

RESULTS

According to the results of one-way ANOVAs, significant differences were detected among color groups on AD, LD, RMS estimate error, ∆x, ∆y, and ∆z data. The lowest AD and LD values were exhibited by the SAGREY group in all implant sites. The SAGREY group was followed by the SABEIGE, SAWHITE, SARED, and SABLUE groups.

CONCLUSIONS

The SAGREY outperformed the other groups in terms of trueness. Although the LD values of all color groups were below the threshold value (<100 µm), only the AD values of the SAGREY, SABEIGE, and SAWHITE groups were clinically acceptable (<0.5°).

Accuracy of intraoral scanning using modified scan bodies for complete arch implant-supported fixed prostheses

STATEMENT OF PROBLEM

The accuracy of intraoral scanning techniques for complete arch implant-supported prostheses remains unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the accuracy of complete arch intraoral scanning using newly modified scan bodies.

MATERIAL AND METHODS

A definitive cast with 6 parallel dental implants (6-246 subgroup, right first molar, right first premolar, right lateral incisor, left lateral incisor, left first premolar, and left first molar) was fabricated. By masking the implants with artificial gingiva, 2 other distinct definitive casts were obtained for 2 subgroups: the 4-24 subgroup, which included 4 implants (right first premolar, right lateral incisor, left lateral incisor, and left first premolar) and the 4-26 subgroup, which also included 4 implants (right first molar, right lateral incisor, left lateral incisor, and left first molar). Three methods were used to record implant location in these 3 subgroups: conventional impression making using the open-tray splinted technique (group CNV), intraoral scanning with the use of conventional scan bodies (group IOS-C), and intraoral scanning using newly modified scan bodies (group IOS-M). To assess accuracy, the best-fit algorithm was used, and root mean square (RMS) values were calculated. Descriptive statistics, including the median, interquartile range, and minimum and maximum values, were used to summarize the variables. Accuracy among different groups was compared, and the influence of the number of implants and the scan distance on the accuracy of group IOS-M was investigated. Appropriate methods were chosen based on the examination of normal distribution and homogeneity of variance, with 1-way analysis of variance (ANOVA) and the Tukey multiple comparison test for data normally (or log-normally) distributed and having equal variances and the Brown-Forsythe ANOVA test and Dunnett T3 multiple comparisons test for data normally (or log-normally) distributed but having unequal variances (α=.05). For data that did not follow a normal or log-normal distribution, the nonparametric Kruskal-Wallis test and Dunn multiple comparisons test was used.

RESULTS

The trueness of group IOS-M ranged from 15.5 to 37.5 µm, with a median (Q1, Q3) of 22.8 (20.3, 25.5) μm, better than that of group IOS-C (P<.001), ranging from 10.1 to 110.0 µm, with a median (Q1, Q3) of 32.1 (26.3, 47.6) μm. Although the trueness of group IOS-M was worse than group CNV (P<.001), ranging from 6.7 to 22.5 µm, with a median (Q1, Q3) of 14.9 (10.5, 17.8) μm, it was within the threshold deemed acceptable to produce clinically suitable complete arch restorations (<59 to 72 µm). The precision of group IOS-M, ranging from 7.2 to 40.8 µm, with a median (Q1, Q3) of 19.5 (16.4, 23.0) μm, was better than that of group IOS-C (P<.001), ranging from 9.8 to 86.8 µm, with a median (Q1, Q3) of 33.7 (25.2, 44.5) μm, but not as good as group CNV (P<.001), ranging from 7.0 to 34.3 µm, with a median (Q1, Q3) of 18.8 (14.3, 21.4) μm. No significant difference in accuracy was found in group IOS-M among subgroups 6-246, 4-26, and 4-24 (P>.05).

CONCLUSIONS

For complete arch implant scans, the modified scan body significantly improved the accuracy of intraoral scanning, with trueness <59 to 72 µm (threshold deemed acceptable to produce clinically suitable complete arch restorations). The accuracy of intraoral scanning using the modified scan bodies was not affected by the number of implants or the scan distance.

Enhancing scanning accuracy of digital implant scans: A systematic review on application methods of scan bodies

STATEMENT OF PROBLEM

Scan bodies play a crucial role in the accuracy of digital implant scans by serving as implant-positioning transfer devices. Previous literature has demonstrated the effects of scan body characteristics on the accuracy of digital implant scans. However, the optimal application methods of scan bodies to enhance scanning accuracy remain unclear.

PURPOSE

The purpose of this systematic review was to determine the optimal application methods of scan bodies to enhance the accuracy of digital implant scans.

MATERIAL AND METHODS

An electronic search was conducted by using the PubMed (MEDLINE), Web of Science, Cochrane Library, and Embase databases from November 2018 to 2023. Relevant references from the included studies were further screened manually for eligibility. Following the population, intervention, comparison, and outcome (PICO) criteria, a research question focused on identifying the optimal application method for effectively using scan bodies to enhance scanning accuracy was developed. Specific inclusion criteria involved in vitro and in vivo studies. The Checklist for Reporting In Vitro Studies (CRIS) guidelines were followed and the assessment of the risk of bias in the included studies was conducted.

RESULTS

Sixteen articles that met the eligibility criteria were included in this systematic review. Two studies investigated the effect of scan body bevel orientation on the accuracy of digital implant scans, and 3 examined the impact of tightening torque on scan bodies. Among the studies focusing on completely edentulous arches, 5 recommended the use of auxiliary geometric devices on the dental arch to enhance scanning accuracy. However, 2 studies reported no improvements in accuracy after splinting scan bodies with thread.

CONCLUSIONS

Different techniques for applying scan bodies, such as configuring bevel orientation, adjusting tightening torque, and attaching auxiliary geometric devices, influence the accuracy of digital implant scans. For scanning completely edentulous arches, attaching auxiliary devices to scan bodies to cover the edentulous ridge effectively enhances scanning accuracy.

[Research progress on accuracy of intraoral digital impressions for implant-supported prostheses in edentulous jaw]

With the rapid development of implant techniques and digital technology, intraoral digital impressions have become a commonly used impression method in implant restoration. At present, the accuracy of intraoral digital impressions directly applied to implant-supported prostheses in edentulous jaw remains inadequate. This is due to the high accuracy requirement of full-arch implant impressions, while there are still technical challenges in intraoral digital impressions about recognition and stitching. In this regard, scholars have proposed a variety of scanning strategies to improve the accuracy of intraoral scans, including mucosal modifications, auxiliary devices and novel scan bodies. At the same time, as a new digital impression technique, stereo photogrammetry has been developing steadily and exhibits promising accuracy. This article reviews the research progress on the accuracy of edentulous full-arch implant impressions and techniques which can improve the accuracy of intraoral digital impressions thus providing a reference for clinical application.

Impact of scanning strategies on the accuracy of virtual interocclusal records in partially edentulous arch using intraoral scanner: an in vitro study

PURPOSE

To evaluate the scanning strategies affecting the accuracy of virtual interocclusal records (VIR) in partially edentulous arches using an intraoral scanner in vitro.

METHODS

A reference model of a partially edentulous arch with implant analogs in positions 45,46 and 47 was constructed. Six pairs of 1-mm diameter metal beads were placed on the gingival tissue as markers for measurement. Four scanning strategies were tested: Quadrant-arch Scan (group 1), Quadrant-arch Scan with Auxiliary occlusal devices (AOD) (group 2), Full-arch Scan (group 3), Full-arch Scan with AOD (group 4). The model was digitalized with a lab scanner as a reference and 15 scans were obtained for each group. The accuracy of VIR was assessed by comparing the experiment data to the reference digital model.

RESULTS

The mean surface deviations of VIR for Groups 1-4 were 89.4 ± 105.2 μm,95.6 ± 132.8 μm,152.3 ± 159.7 μm and 107.6 ± 138.2 μm respectively. Quadrant-arch scans resulted in lower errors of VIR than full-arch scan (P < 0.001). There was a significant interaction between the AOD and scanning span (P = 0.017). The Quadrant-arch scan with AOD　(group 2) produced the least error in the distally extended edentulous area.

CONCLUSIONS

Quadrant-arch scans showed better accuracy of VIR than full-arch scans across all tooth positions. The combination of AOD and quadrant-arch scan further enhances VIR accuracy in distally extended edentulous areas.

Complete-arch accuracy of seven intraoral scanners measured by the virtual-fit method

OBJECTIVES

This study compared the accuracy of seven intraoral scanners (IOS) by the virtual-fit method.

METHODS

Four maxillary arches with tooth abutments were scanned with an industrial reference scanner (n=1) and by Aoralscan3, EmeraldS, Helios600, Lumina, Mediti700, Primescan, and Trios5 IOSs (each n=12). Two complete-arch fixed frameworks were designed on each IOS scan with a 70 µm (group 70) and a 90 µm internal cement space (group 70+20, additional 20 µm at the margin). The virtual-fit method was comprised of superimposing the framework designs onto the reference scan using a non-penetrating algorithm simulating the clinical try-in. Internal and marginal gaps were measured. Precision was estimated by the mean absolute errors (MAE).

RESULTS

In group 70, Mediti700 (43 µm), Primescan (42 µm), and EmeraldS were in the best homogenous subset for the marginal gap, followed by the Lumina (67 µm), Aoralscan3 (70 µm), and Trios5 (70 µm), whereas Helios600 (118 µm) was in the third subset. Based on the MAE at the margin, Mediti700, Trios5, and EmeraldS were in the first-best homogenous subset, followed by Primescan. Lumina and Helios600 were in the third subset, and Aoralscan3 was in the fourth subset. In group 70+20, the marginal gap was significantly decreased for Lumina and Aoralscan3, whereas MAE significantly decreased for EmeraldS and Aoralscan3. The rank of IOSs was similar for the internal gap.

CONCLUSION

EmeraldS, Mediti700, Primescan, and Trios5 meet the marginal and internal fit criteria for fixed tooth-borne complete arch restorations. Increasing the cement space during design could enhance restoration fit.

CLINICAL SIGNIFICANCE

The virtual-fit alignment method can effectively evaluate the accuracy of different intraoral scanners, offering valuable clinical guidance for distinguishing among them. Recent software and hardware versions of long-standing IOS manufacturers are suitable for fabricating complete arch restoration.

The Effect of Image Count on Accuracy in Digital Measurements in Dentistry

Objective: This study investigated how the number of images collected for digital measurements in dentistry affects accuracy compared with traditional methods. Methods: A Frasaco maxillary model was scanned using a SHINING 3D AutoScan-DS-MIX dental 3D scanner to create an STL file. The maxilla was molded 10 times using polyvinyl siloxane (Zhermack Elite HD+) to produce plaster models, which were scanned with the same reference scanner to generate 10 STL files. The Frasaco model was scanned 10 times, capturing images in intervals of 800-1000, 1000-1200, and 1200-1500 using a 3Shape TRIOS 3 intraoral scanner, creating additional STL files. These were analyzed with reverse engineering software. Results: The most accurate measurements were obtained using 1200-1500 images. Conventional impression techniques performed significantly worse. There was a significant difference between the groups Digital 1200-1500 and Plaster (p < 0.001) and between Digital 800-1000 and Plaster (p = 0.007). No significant difference was found when the digital groups were compared among themselves. There was also no significant difference between the Plaster and Digital 1000-1200 groups. To compare precision values that were normally distributed across three or more methods, a one-way ANOVA was used. Trueness values that were not normally distributed with three or more methods were compared employing the Kruskal-Wallis test. Conclusions: Different image counts affect digital measurement accuracy. The most accurate measurements were obtained when collecting 1200-1500 images. Conventional impression techniques were shown to perform significantly worse than digital impression.

A digital approach to creating a positioning tray for a multiple implant impression and its clinical application: A dental technique

A workflow is described for fabricating a custom complete arch implant positioning tray for the impression of multiple implants. In this technique, a complete arch virtual cast with abutments is obtained by intraoral scanning. Details for the tray including extension range, thickness, and impression post perforation sites can be designed from this cast. This positioning tray not only eliminates the conventional complicated manufacturing procedures but can also accurately obtain the positional relationship between implants and the morphology of the alveolar mucosa, saving clinical time.

Effect of a Novel 'Scan Body' on the In Vitro Scanning Accuracy of Full-Arch Implant Impressions

OBJECTIVE

This in vitro study aimed to determine whether a newly designed arcuate scan body can improve intraoral scanning accuracy for implant rehabilitation of edentulous jaws.

MATERIAL AND METHODS

A master model containing 4 implant abutment replicas was fabricated and digitized with different scan bodies using an intraoral scanner. Four types of scan bodies were evaluated: original scan bodies (group OS), computer-aided design and computer-aided manufacturing (CAD/CAM) scan bodies without extension (group CS), CAD/CAM scan bodies with straight extension (group CSS), and CAD/CAM scan bodies with arcuate extension (group CSA). Conventional splinted open-tray impressions (group CI) were used as controls. The master model and the poured casts were digitized using a laboratory scanner. Impressions were repeated 10 times each in 5 groups. Scans in standard tessellation language format were exported to reverse engineering software and root mean square (RMS) values were used for trueness and precision assessments. In each group, 45 RMS values were acquired for precision evaluation and 10 RMS values were obtained for trueness assessment. Statistical evaluation was performed with the Kruskal-Wallis test and Dunn-Bonferroni test (α = 0.05).

RESULTS

The median trueness values were 41.40, 55.95, 39.80, 39.75, and 22.30 μm for group OS, CS, CSS, CSA, and CI, respectively. CI showed better trueness than OS (P = .020), CS (P < .001), and CSS (P = .035). The median precisions for group OS, CS, CSS, CSA, and CI were 47.40, 51.50, 43.90, 25.20, and 24.60 μm. respectively. The precision of CSA and CI were higher than OS (P < .001), CS (P < .001), and CSS (P < .001). Between CI and CSA, there was no significant difference (P = 1.000).

CONCLUSIONS

For full-arch implant rehabilitation, the scan body with arcuate extension could improve the intraoral scanning precision and showed similar 3-dimensional discrepancy compared to conventional splinted open-tray impressions.

Effect of auxiliary geometric devices on the accuracy of intraoral scans in full-arch implant-supported rehabilitations: An in vitro study

OBJECTIVES

The aim of the present in vitro study was to evaluate the effect of a novel auxiliary geometric device (AGD) on the accuracy of full-arch scans captured with 3 different intraoral scanners (IOS).

METHODS

An edentulous maxillary model with four internal connection implant replicas was scanned using 3 different IOS: iTero Element 5D (ITERO) (Align Technology, Tempe, AZ, USA), Trios 4 (TRIOS) (3Shape A/S, Copenhagen, Denmark), and Carestream 3700 (CS) (Carestream Dental, Atlanta, USA). Thirty-six scans were taken with each IOS, 18 with the AGD in place, and 18 without the AGD. A digital master model was created using an industrial optical scanner (ATOS compact Scan 5M, GOM GmbH, Braunschweig, Germany). The master and IOS models were aligned using the scan bodies as a reference area. A surface comparison was performed, and deviation labels were exported for each scan body to evaluate the linear and angular deviation. Total body, platform and angular deviations were measured.

RESULTS

The use of AGD resulted in a statistically significant increase of angular deviation: 0.87° (SD=0.21) in the AGD group versus 0.64° (SD=0.46) in the no AGD group (p-value=0.005). The difference between the AGD and no AGD groups was not statistically significant for total body and platform deviation values (p-value=0.051 and 0.302 respectively). Using AGD, ITERO showed a statistically significant increase in angular deviation (mean difference=-0.46 µm, p-value=0.002) and a decrease in mean platform deviation (mean difference=63.19 µm, p-value<0.001). No statistically significant differences were found for the other IOS.

CONCLUSIONS

The use of AGD did not add benefit on CS and TRIOS. On ITERO, there was an improvement in platform deviation, that was outweighed by the worsening of the angular deviation.

CLINICAL SIGNIFICANCE

In vitro data suggest that intraoral scans can be successfully used in full-arch cases. The use of AGD has no additional benefit on CS and TRIOS. On ITERO there was an improvement in platform deviation that was outweighed by the worsening of the angular deviation. Translational application to clinical practice deserves further investigation, taking into account patient-related and anatomical variables.

Novel complete-arch pillar system (CAPS) to register implant position and maxillomandibular relationship in one single visit

OBJECTIVES

This article presents a novel complete-arch pillar system (CAPS) to register implant position and maxillomandibular relationship in one single visit for implant-supported fixed complete dental prostheses (IFCDPs).

MATERIAL AND METHODS

The novel system presents a 3-unit toolset comprising intraoral scan bodies (ISBs), lateral pillar attachments (LPAs) and occlusal pillar attachments (OPAs). A 2-stage single visit workflow by an intraoral scanner (Trios 5) was introduced. The first stage "Screw-Scan-Done" was used to describe complete-arch intraoral implant scanning using LPAs. The second stage "Screw-Occlude-Done" involved virtual occlusal recording using OPAs. Two patients with one single edentulous arch were selected for this study. In the first patient, 6 bone level implants (Bone Level Tapered, Straumann) were placed in the edentulous maxilla at positions 12, 14, 16, 22, 24 and 26. In the second patient, 4 bone level implants (NobelActive CC, Nobel Biocare) were placed in the edentulous mandible at positions 32, 35, 42 and 45. A CAD-CAM procedure was initiated with the acquired IOS data to fabricate an interim IFCDP at the same day. Periapical radiographs were obtained of the implant-prosthetic connection of the definitive IFCDPs to verify the passive fit. Metrology software (Geomagic Qualify, 3D Systems - Matlab, Mathworks) was used to assess the implant analogs position in the 3D-printed casts used for fabricating the definitive IFCDPs. A quantitative occlusal relationship analysis was performed with IOS.

RESULTS

Radiographic examination revealed no gaps at implant-prosthetic connection of the definitive IFCDPs. The 3D-printed casts showed an overall average distance deviation within the clinically acceptable range of errors of 150 µm. Quantitative occlusal relationship analysis with IOS showed well-distributed contacts.

CONCLUSION

Within the limitations of this study, the following conclusions can be drawn: (1) A 3-unit toolset with ISBs, LPAs and OPAs allows to register the implant position and maxillomandibular relationship in one single visit; (2) the 2-stage clinical workflow with the CAPS system facilitates the IOS data acquisition for fabrication of an interim IFCDP at the same day; (3) a passive fit was demonstrated for the interim and the definitive IFCDPs.

CLINICAL SIGNIFICANCE

The CAPS system can help clinicians to register the implant position and the maxillomandibular relationship in one single visit for the fabrication of an IFCDP.

Effect of artificial landmarks of the prefabricated auxiliary devices located at different arch positions on the accuracy of complete-arch edentulous digital implant scanning: An in-vitro study

OBJECTIVES

To examine the effect of artificial landmarks of prefabricated auxiliary devices (PAD) located at different arch positions on the accuracy of complete-arch edentulous digital implant scanning.

METHODS

A reference model containing four analogs and PAD were fabricated by a 3D printer (AccuFab-C1s, 3DShining). 10 digital scans were performed using an intraoral scanner (Aoralscan 3, 3DShining), sv 1.0.0.3115, with artificial landmarks located at different arch positions: group I, without any artificial landmarks; group II, with artificial landmarks at the anterior region; group III, with artificial landmarks at the posterior region. group IV: with artificial landmarks at both anterior and posterior regions. For group V: Conventional open-tray splinted impressions. The reference file and conventional stone casts were digitalized by using a dental laboratory scanner. The related files were imported into inspection software for trueness and precision assessment. Statistical analysis was performed with One-way ANOVA and Kruskal-Wallis test. The level of significance was set at α=0.05.

RESULTS

For the global accuracy assessment, significantly higher global trueness was seen in group II (p < 0.01), III (p < 0.001), IV (p < 0.001) and V (p < 0.001) than group I. Significantly higher global precision was seen in group III (p < 0.001), IV (p < 0.001) and V (p < 0.001) than group I. For the local accuracy assessment, the PAD primarily improved accuracy on the linear deviations.

CONCLUSIONS

Artificial landmarks of PAD at different arch positions significantly influenced the scanning accuracy. Applying the PAD in group IV could achieve comparable outcomes to conventional open-tray splinted impressions. Artificial landmarks on the posterior region may be more pivotal than those on the anterior region.

CLINICAL SIGNIFICANCE

Group IV could achieve comparable accuracy to conventional open-tray splinted impressions.