Recommendations for successful virtual patient-assisted esthetic implant rehabilitation: A guide for optimal function and clinical efficiency

Trueness and precision of a handheld, a desktop and a mobile 3D face scanning system: An in vitro study

OBJECTIVE

This in vitro study investigated the trueness and precision of three different face scanning systems: a handheld, a desktop and a mobile 3D face scanning system.

MATERIAL AND METHODS

Fourteen landmarks were placed on a mannequin head, and sixteen inter-landmark distances were measured using a digital vernier caliper, repeated 20 times over 80 days. Three 3D face scanning systems were evaluated: a handheld (Metismile; Shining 3D Tech Co., Hangzhou, China), a desktop (RAYFace v2.0; Ray Co., Ltd., Gyeonggi-do, Korea), and a mobile application (Heges, Simon Marinek) on a smart device (iPad Pro X, Apple Inc., Cupertino, CA). Sixty facial scans were analyzed using metrology software (Geomagic Control X), and inter-landmark distances were compared to anthropometric measurements. Trueness was determined by absolute linear deviation and analyzed using one-way ANOVA, with Bonferroni and Tamhane tests for significant variance. Precision was compared to anthropometric measurements and analyzed using Kruskall-Wallis test.

RESULTS

3D analysis showed that the handheld scanner had the highest trueness (0.18 ± 0.15 mm) and precision (0.22 ± 0.04 mm). The desktop scanner had a trueness of 0.35 ± 0.26 mm and precision of 0.61 ± 0.18 mm, while the mobile scan application had a trueness of 0.54 ± 0.34 mm and precision of 0.47 ± 0.12 mm. All systems showed the highest trueness for vertical measurements compared to horizontal measurements. In the lower face, the precision was higher than anthropometric measurements for all 3D face scanning systems.

CONCLUSIONS

The handheld scanner demonstrated the highest trueness and its precision surpassed anthropometric measurements. The desktop scanner outperformed the mobile scan application in trueness but not in precision.

CLINICAL SIGNIFICANCE

The handheld, the desktop and the mobile face scanning system showed clinically acceptable trueness (< 0.6 mm) and could be used for virtual facebow transfer. All 3D face scanning systems in the present study demonstrated superior precision in the lower face compared to anthropometric measurements.

Influence of Head Circumference on the Accuracy of Facial Scanning: An In vitro Study

OBJECTIVES

This study aimed to investigate the impact of head circumference on the accuracy of three-dimensional (3D) facial scans, focusing on trueness and precision across three mannequin heads of different sizes.

MATERIAL AND METHODS

Three 3D-printed mannequin heads with circumferences of 30, 50, and 65 cm were used. Ten facial landmarks were identified to measure seven interlandmark distances and two angles. Direct anthropometric measurement, serving as the reference value, was taken using a digital vernier calliper for linear distance, and angle was calculated using the law of cosines. Each head was scanned six times using two systems: a dual-structured light facial scanner (iTom) and a stereophotogrammetry system (3dMD). Digital measurements were analysed using Meshlab and Blender for distances and angles, respectively. Trueness values were determined by comparing measurements to reference measurements, while precision values were derived from the variability among the six scans. Statistical analysis was performed using the Kruskal-Wallis test due to nonhomogeneous variances, followed by Bonferroni correction for pairwise group comparisons.

RESULTS

For each scanning system, overall deviations in trueness and precision significantly increased with head circumference. Five of the seven distances and one angle showed significant compromises in trueness with larger head circumferences. Most measurements exhibited significant precision decreasing due to head circumference changes, except for N-Pn and Pn-Sn. Additionally, 3dMD displayed higher overall trueness compared to iTom, with five out of seven linear measurements and one angular measurement showing better results.

CONCLUSION

Head circumference significantly affects both trueness and precision of 3D facial scans for both technologies, suggesting that facial imaging should be used with caution for larger faces. Selecting an appropriate scanning system, such as 3dMD, can help mitigate the negative effects of scanning larger objects.

Accuracy (trueness and precision) of 3-dimensional virtual patients: An in vitro investigation of different facial scanners and digital integration techniques

OBJECTIVES

To investigate the influence of different facial scanners and integration approaches on the accuracy of virtual dental patients (VDPs).

METHODS

Forty VDPs were generated using a head mannequin and two facial scanners: 1) an industrial scanner and 2) a smartphone scanner. For each scanner, two integration methods were applied: 1) integration by virtual facebow scan and 2) integration by nose-teeth scan. This resulted in four VDP groups, with ten repetitions for each group (n = 10). A cone beam computed tomography (CBCT) scan of the mannequin served as the reference. The linear deviations of the maxillary arches at teeth #16, #21, and #26, as well as the angular deviations of the occlusal planes, were measured to assess accuracy.

RESULTS

No significant trueness differences were found between the scanners (p = 0.78 for tooth #16, p = 0.84 for tooth #21, p = 0.35 for tooth #26, p = 0.18 for angular deviations) or between the integration techniques (p = 0.42 for tooth #16, p = 0.29 for tooth #21, p = 0.76 for tooth #26, p = 0.61 for angular deviations). In terms of precision, the industrial facial scanner demonstrated superior outcomes (p < 0.001 for teeth #16, #21, #26, and angular deviations). No significant precision differences were found between the two integration techniques for teeth #16 (p = 0.17) and #26 (p = 0.25), or for angular deviations (p = 0.27); however, the nose-based integration technique showed higher precision for tooth #21 (p = 0.01).

CONCLUSIONS

The smartphone-based facial scanner exhibited trueness comparable to that of the industrial facial scanner, though with reduced precision. The nose-based integration technique demonstrated better accuracy compared to the virtual facebow-based technique.

CLINICAL SIGNIFICANCE

The smartphone-based facial scanner achieves trueness comparable to the industrial facial scanner for VDP integration. Additionally, the nose-based integration technique offers a viable alternative to the virtual facebow-based approach, with a simplified scanning and integration process.

Impact of scanning interruptions on accuracy of implant-supported full-arch scans: An in-vitro pilot study

PURPOSE

To assess the impact of involuntary interruptions (simulating tracking loss by moving the scanner out of its focal distance) and voluntary interruptions (pressing the scanner's turn-on button) on the accuracy of implant-supported full-arch scans using an intraoral scanner (TRIOS 5, version 22.1.10; 3Shape; Copenhagen, Denmark).

MATERIALS AND METHODS

An edentulous model with four implants was digitized with an industrial scanner (Artec Micro II; Artec 3D) to create a reference scan. Four groups (n = 30) were established based on the number of interruptions during scanning: Zero Group (no interruptions; control group), 6-V Group (six voluntary interruptions), 6-I Group (six involuntary interruptions), and 12-I Group (twelve involuntary interruptions). Primary outcome was accuracy assessed by the Root Mean Square (RMS) method. Secondary outcomes included scanning time and the number of photograms. Data were analyzed using one-way ANOVA and post hoc Tukey multiple comparison tests (α=0.05).

RESULTS

A total of 120 digital scans were conducted. The Zero group achieved a RMS error of 291 ± 47 µm, a scanning time of 68 ± 6s, and 1320 ± 129 photograms. 6-V group significantly reduced RMS error (MD -102 µm [IC 95 %: -141, -63]), decreased scanning time (MD -20s [IC 95 %: -25, -17]), and reduced photograms (MD -415 photograms [IC 95 %: -506, -324]) compared to the control group (P<.001). Simulations of 6 or 12 involuntary interruptions did not affect accuracy compared to the control group (P>.05).

CONCLUSIONS

Voluntary interruptions during scanning, achieved by pressing the scanner's turn-on button, appear to enhance accuracy due to image preprocessing, while involuntary interruptions had no significant impact on the accuracy of implant-supported full-arch scans.

CLINICAL SIGNIFICANCE

Voluntary stop during scanning implant-supported full-arches may result in better-fitting prostheses owing to higher scan accuracy and efficiency.

Computer-Assisted Porcelain Laminate Veneer Preparation: A Scoping Review of Stereolithographic Template Design and Fabrication Workflows

Computer-assisted preparation of porcelain laminate veneers (PLVs) using stereolithographic templates has been developed to enhance the accuracy of tooth preparation. However, the digital workflows involved in guided PLV preparation remain inconsistently defined across various practices. Therefore, this scoping review aimed to examine publications on computer-assisted PLV preparation to identify the key stage of digital workflows involved in designing and fabricating stereolithographic templates, as well as to highlight the limitations of various template designs. This scoping review aimed to identify publications on digital workflows for designing and fabricating stereolithographic templates in computer-assisted porcelain laminate veneer preparation. A systematic search on MEDLINE/PubMed, Web of Science and Scopus identified English-language articles published from 2014 to March 2024. Eligible articles focused on digitally designed and fabricated tooth reduction templates for porcelain laminate veneers, excluding conventional tooth preparation procedures for tooth reduction assessment. Seven clinical reports were included, demonstrating various 3D data acquisition techniques for virtual patient generation. All articles described virtual diagnostic wax-ups on digital casts, with two using a virtual articulator. Only five articles documented chair-side mock-ups with resin trial restorations to evaluate planned dental esthetics. Additionally, virtual tooth preparation prior to templates design was included in only four articles. The templates were designed using different software and ranged from simple designs with access windows to complex stacked templates with rotary instrument sleeved windows. Each template design had limitations affecting tooth reduction accuracy. All articles reported printing templates in clear acrylic resin using different technologies. In conclusion, the review highlights a lack of standardization in the digital workflow for designing stereolithographic templates for PLVs. Establishing a sound protocol for designing the tooth reduction templates is essential to ensure the accuracy and consistency of veneer preparation.

A fully digital planning protocol for dynamic computer-assisted zygomatic implant surgery based on virtual surgery simulation: A dental technique

Dynamic navigation-guided zygomatic implant (ZI) surgery has been a preferred option for achieving optimal prosthetic-driven implant placement. However, during the actual surgical procedure, surgical execution may still be hindered by environmental factors such as mouth opening. A fully digital planning protocol is described that integrated the patient's maxillofacial soft tissue information and virtual surgical handpiece with the drills on the implant planning path to ensure the precise, time-saving, and smooth implementation of dynamic navigation-guided ZI surgery.

Maxillomandibular relationship and virtual facebow integration in complete-arch intraoral implant scan: A novel clinical technique

This clinical report introduces a novel clinical technique to create a 3D virtual patient for transferring the edentulous maxillary arch position with maxillomandibular relationship by using a facial scan device and an intraoral scanner and omitting CBCT imaging.