Accuracy of a patient 3-dimensional virtual representation obtained from the superimposition of facial and intraoral scans guided by extraoral and intraoral scan body systems

Techniques and accuracy for aligning facial and intraoral digital scans to integrate a 3-dimensional virtual patient: A systematic review

STATEMENT OF PROBLEM

The optimal method of aligning intraoral scans with facial scans to generate a 3-dimensional (3D) virtual patient remains unclear. Distortions in the alignment of intraoral and facial scans would lead to an inadequate virtual patient representation and, therefore, to inadequate diagnosis and treatment planning.

PURPOSE

The purpose of this systematic review was to evaluate the available techniques for generating a 3D virtual patient by aligning facial and intraoral scans and to assess their accuracy.

MATERIAL AND METHODS

A systematic search was conducted in 3 databases: Medline, Scopus, and Web of Science. A manual search was also conducted. Specific descriptors were used to identify alignment techniques. Two independent reviewers screened titles and abstracts, with a third independent reviewer resolving ambiguities. A qualitative analysis was performed, and interexaminer agreement was assessed using the Cohen kappa statistic.

RESULTS

After screening, 48 of the 2832 identified articles were included for qualitative analysis. They focused on 3 alignment techniques: guided by retracted facial scans, extraoral scan bodies, and perioral intraoral scans. Interexaminer agreement was high (kappa=0.82 to 0.88). Integration techniques guided by extraoral scan bodies, influenced by extraoral scan body design and protocols, showed the best accuracy. The outcome variables for the evaluation of the effectiveness of these protocols were heterogeneous.

CONCLUSIONS

Integrating facial and intraoral scans was found to enhance diagnosis and treatment planning by providing essential esthetic and functional parameters. Integration techniques guided by extraoral scan bodies and combination techniques showed higher accuracy, especially for complex implant-supported prostheses or edentulous patients.

Positional accuracy of intraoral scan alignment to a facial scan using structured light scanning and trial denture base with occlusal rim markers in patients with complete maxillary edentulism

STATEMENT OF PROBLEM

Creating precise 3D virtual head models for patients with complete maxillary edentulism remains challenging owing to the lack of natural landmarks and limitations of current image-matching technologies.

PURPOSE

The purpose of this study was to evaluate the positional accuracy of intraoral scan alignment to structured light-based facial scans using varying sizes and positions of occlusal rim markers under maxillary edentulous conditions.

MATERIAL AND METHODS

Radiopaque artificial markers of 3 sizes (2, 4, and 6 mm) were made and attached to the maxillary occlusal rim of a completely edentulous patient at different positions (midline-canine [MC], midline [M], canine [C]). Facial scans were obtained of the patient by using a structured light facial scanner under 9 experimental conditions (size-location: 2MC, 2M, 2C, 4 MC, 4M, 4C, 6MC, 6M, and 6C; 5 scans under each condition). Intraoral scans were aligned to the facial scans using stepwise images matching the occlusal rim scan casts. The alignment accuracy was evaluated by comparing the intraoral scan with a reference position established using cone beam computed tomography data. Measured variables included anterior and posterior linear deviations and angular deviation of the arch plane. Statistical analysis was conducted using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni correction (α=.05).

RESULTS

The 4-mm and 6-mm marker groups exhibited significantly lower deviation in image registration than the groups without markers and those with 2-mm markers (P<.001). Regarding the marker position, the midline-canine group exhibited the lowest deviation value, followed by the midline and canine groups. Markers positioned in the midline exhibited less deformation compared with those in the canine region.

CONCLUSIONS

Occlusal rim markers can be used to align intraoral and facial scans in patients with complete maxillary edentulism when structured light face scanning is included. Markers with a clearly recognizable size in facial scans are less prone to deformation in the facial midline area.

Evaluation of the accuracy (trueness, precision) and processing time of different 3-dimensional CAD software programs and algorithms for virtual cast alignment

OBJECTIVES

This in vitro study aimed to evaluate the impact of different alignment algorithms and CAD software programs on alignment accuracy (trueness and precision) and processing time.

METHODS

A mandibular typodont was digitized using a laboratory scanner (L2i) to obtain a reference standard tesselletion language (STLr) file. It was then scanned with an intraoral scanner (Primescan) and digitally duplicated ten times (n = 10). Each scan was aligned with the STLr using 42 combinations of 3D CAD software and alignment algorithms. The tested software programs included Blender for Dental, BlueSkyPlan, Dental CAD App (Exocad), Medit Design, NemoSmile, and Meshmixer. Alignment accuracy (trueness and precision) and processing time were recorded using Python software (v3.8). Statistical analysis was performed with a two-way ANOVA test (α = 0.01) to identify overall differences, followed by a post hoc Tukey Honestly Significant Difference test (α = 0.05) to establish rankings.

RESULTS

Significant differences in alignment accuracy were observed based on the software and algorithm used, affecting both trueness (p<.01) and precision (p<.01). Processing time also varied significantly (p<.01). Post hoc analysis identified the optimal algorithm for each software, revealing variations in trueness, precision, and processing time among the optimal versions. Medit Design achieved the best overall performance by combining high accuracy with the fastest processing time, while Meshmixer exhibited the lowest accuracy due to its lack of advanced algorithms.

CONCLUSIONS

The choice of CAD software and alignment algorithm significantly influences alignment accuracy and efficiency. Best-fit and section-based provided the best results, offering valuable insights into the optimization of digital workflows in prosthodontics.

CLINICAL SIGNIFICANCE

Alignment protocols must be tailored to the specific CAD software program used, as no universal protocol was effective across all tested software. Optimizing alignment protocols reduces errors, enhances prosthodontic outcomes, and improves the reliability and efficiency of clinical and laboratory workflows, ultimately ensuring better patient care and treatment success.

Facial Scans in Clinical Dentistry and Related Research: A Scoping Review

This scoping review examined the adoption of three-dimensional (3D) facial scanning technology in clinical dentistry, focusing on the range of scanning techniques, clinical applications, and related implementation trends. A systematic literature search of three major databases identified studies published between January 2020 and June 2024 that described 3D facial scanning of human participants in clinical dental settings. After screening 224 records, 48 from 19 countries met the inclusion criteria. Both clinical studies and case/technical reports showed that facial scanning was used in multiple specialties, including orthodontics, prosthodontics, and maxillofacial surgery, primarily for diagnosis, treatment planning, and outcome assessment. The technologies such as stereophotogrammetry, structured light scanning, laser scanning, and mobile device-based solutions vary in accuracy and ease of integration. Mobile scanning, in particular, is growing in importance due to lower cost, accessibility, and compatibility with digital workflows. Despite these advances, standardized protocols for integrating facial scans with other digital records, such as cone beam computed tomography and intraoral scans, remain underdeveloped. This review demonstrates the growing importance of 3D facial scanning in improving clinician-patient communication and identifies areas where further research is needed, including long-term validation, cost-effectiveness, and standardized data management.

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.

Accuracy of registration between digitized extraoral scan bodies and virtual casts: Effect of the edentulous area, tooth anatomy, and registration method

STATEMENT OF PROBLEM

Digitized analog records have been used for the superimposition of intraoral and facial scans. However, the discrepancy in the registration between the digitized occlusal records contained on extraoral scan bodies and the maxillary virtual cast remains uncertain.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of the registration method, edentulous area, and tooth anatomy on the accuracy of the alignment between the digitized extraoral scan body (ESB) and the maxillary virtual cast.

MATERIAL AND METHODS

A scannable ESB and a set of 8 maxillary casts (2 completely dentate simulating unworn and worn tooth anatomy, 5 partially edentulous, and 1 completely edentulous were printed (Pro 95S; SprintRay). Four zirconia markers were attached to the index of the ESB and each of the evaluated casts. Each cast was positioned into the tray of the ESB using occlusal registration material (O-Bite; DMG). The ESB and each corresponding evaluated cast were digitized by using a calibrated laboratory scanner (T710; Medit). Then, each cast and index of the ESB were scanned separately by using the same scanner (n=10). Using a CAD software program, each virtual cast was attached to the ESB 10 times by using 3 different alignment methods: an analog using an iterative closest points (ICP) algorithm and 2 semimanual alignments using a best-fit algorithm for the entire data set with or without including the edentulous areas. A metrology software program was used to measure the linear distance between the corresponding gauge balls and the angulation between the planes defined by the markers on the cast and the ESB. The measurements from the scans of the casts attached to the tray were used as a reference to calculate the discrepancies in each experimental group. Α P value threshold of <.05 was used to determine statistical significance.

RESULTS

The best-fit algorithm registration method produced better trueness and precision than the manual point-to-point registration (P<.05). When the edentulous areas were not included in the analog surface record, the trueness and precision of the best-fit algorithm were significantly worse (P<.05). In respect of tooth anatomy, no significant difference in trueness and precision was found among the investigated groups (P>.05). The completely dentate groups presented significantly better trueness than the edentulous groups (P<.05).

CONCLUSIONS

The accuracy of the registration between digitized occlusal surface scans and digital casts was influenced by the registration method, as well as by the location and extent of the edentulous areas.

Fully digital workflow for the fabrication of polycarbonate-based resin diagnostic and interim flexible removable partial dentures: A dental technique

This dental technique describes a fully digital workflow for the design and fabrication of interim removable partial dentures (RPDs) using a polycarbonate-based computer-aided design and computer-aided manufacture (CAD-CAM) material with custom-designed prosthetic teeth as an alternative to conventional interim RPDs with unesthetic metal clasps.

Trueness and precision of facial scan and virtual patient representation workflow

PURPOSE

To investigate the feasibility and accuracy (trueness and precision) of facial scanning and virtual patient representation (VPR).

MATERIALS AND METHODS

One participant was recruited and informed consent was obtained. VPR was performed 30 times with a custom fabricated intraoral scan body (ISB). Thirteen adhesive markers were added to the face as an extraoral scan body (ESB). Two facial scans were obtained for each VPR using an infra-red laser accessory sensor (Structure sensor; Occipital Inc) mounted on a computer tablet (iPad Pro; Apple Inc), including one with seated ISB and one without ISB. Two maxillary intraoral scans were obtained using an intraoral scanner (Omnicam; Dentsply Sirona) with and without the ISB. All files were imported to a dental software program (exocad; exocad GmbH) and VPR was obtained by aligning the facial and IOS scans using the ISB and ESB as common elements for alignment. Five fiducial face landmarks, four intraoral dental landmarks, and six perioral landmarks were selected for measurements. A total of 32 linear measurements, including 14 face-face (for facial scan accuracy) and 18 face-dental (for VPR accuracy) representing total face, lower face, and perioral regions, were performed directly using a digital caliper (FINO Digital Caliper; FINO GmbH) and virtually on the VPR. Trueness was evaluated by mean absolute difference (MAD) between the virtual and direct measurements, and the standard deviation represented Precision. Statistical analyses were performed with a statistical software package (IBM SPSS Statistics v25; IBM Corp), with α = 0.05. Data were analyzed for normality with Shapiro-Wilk test, and 1-sample t- (or Wilcoxon signed rank test), technical error of measurement (TEM), and relative error magnitude (REM).

RESULTS

The facial scan had 2.04, 1.66, 0.8 trueness, and 1.05, 0.92, 0.91 precision for total, lower face, and perioral regions. VPR had higher MAD (lower trueness) than facial scan, including 3.32, 2.40, 1.21 trueness and 2.2, 1.47, 1.2 precision for total, lower face, and perioral regions. Both TEM and REM were lowest for the perioral region and increased with increasing measurement distance.

CONCLUSION

Error in face scanning increased with increased distance and intricate details. VPR accuracy was lower than face scan accuracy because of added errors in the alignment process. The investigated VPR workflow might be feasible for treatment planning and smile design. However, it would be unreliable for more demanding prostheses manufacturing purposes.

The Orientation in Space of the Maxillary Arch: New and Old Devices in the Prosthetic Digital Workflow

OBJECTIVE

In extensive prosthetic rehabilitations and in those involving the anterior area, a correct 3D spatial position is of fundamental importance for effective communication between the clinician and the dental technician. The aim of this article is to analyze the different methods used to position in space and/or in an articulator the maxillary arch in analog workflows highlighting shortcomings and difficulties in order to understand how to overcome them when employing digital workflows.

OVERVIEW

Traditional mechanical devices, such as anatomical, kinematic, esthetic and postural facebows, have clear indications, but also limitations, especially in cases of skeletal asymmetries. Modern digital tools, including photography, CBCT, facial scanners and jaw recording devices, are here critically analyzed to illustrate the advantages of working in a virtual space.

CONCLUSIONS

The adoption of digital tools in the prosthetic workflow represents a significant improvement compared to traditional techniques, as it reduces errors and artifacts of registration and transfer of the position of the maxillary arch in the articulator space. This contributes to more predictable esthetic and functional results, with a positive impact for clinicians and technicians, improving clinical-laboratory communication, operational efficiency and overall quality of work.

CLINICAL SIGNIFICANCE

The integration of digital tools into prosthetic workflows represents an important advancement in clinical practice since they reduce human error and facilitate communication between the clinician and the laboratory. When carrying out rehabilitations involving changes in esthetics or occlusal plane orientation, the proper and accurate positioning of the upper arch in space is particularly relevant.

An overview of the different digital facebow methods for transferring the maxillary cast into the virtual articulator

OBJECTIVES

The purposes of this study were to classify the described digital facebow techniques for transferring the maxillary cast into the semi-adjustable virtual articulator based on the digital data acquisition technology used and to review the reported accuracy values of the different digital facebow methods described.

OVERVIEW

Digital data acquisition technologies, including digital photographs, facial scanners, cone beam computed tomography (CBCT) imaging, and jaw tracking systems, can be used to transfer the maxillary cast into the virtual articulator. The reported techniques are reviewed, as well as the reported accuracy values of the different digital facebow methods.

CONCLUSIONS

Digital photographs can be used to transfer the maxillary cast into the virtual articulator using the true horizontal reference plane, but limited studies have assessed the accuracy of this method. Facial scanning and CBCT techniques can be used to transfer the maxillary cast into the virtual articulator, in which the most frequently selected references planes are the Frankfort horizontal, axis orbital, and true horizontal planes. Studies analyzing the accuracy of the maxillary cast transfer by using facial scanning and CBCT techniques are restricted. Lastly, optical jaw trackers can be selected for transferring the maxillary cast into the virtual articulator by using the axis orbital or true horizontal planes, yet the accuracy of these systems is unknown.

CLINICAL IMPLICATIONS

Digital data acquisition technologies, including digital photographs, facial scanning methods, CBCTs, and optical jaw tracking systems, can be used to transfer the maxillary cast into the virtual articulator. Studies are needed to assess the accuracy of these digital data acquisition technologies for transferring the maxillary cast into the virtual articulator.

An overview of artificial intelligence based applications for assisting digital data acquisition and implant planning procedures

OBJECTIVES

To provide an overview of the current artificial intelligence (AI) based applications for assisting digital data acquisition and implant planning procedures.

OVERVIEW

A review of the main AI-based applications integrated into digital data acquisitions technologies (facial scanners (FS), intraoral scanners (IOSs), cone beam computed tomography (CBCT) devices, and jaw trackers) and computer-aided static implant planning programs are provided.

CONCLUSIONS

The main AI-based application integrated in some FS's programs involves the automatic alignment of facial and intraoral scans for virtual patient integration. The AI-based applications integrated into IOSs programs include scan cleaning, assist scanning, and automatic alignment between the implant scan body with its corresponding CAD object while scanning. The more frequently AI-based applications integrated into the programs of CBCT units involve positioning assistant, noise and artifacts reduction, structures identification and segmentation, airway analysis, and alignment of facial, intraoral, and CBCT scans. Some computer-aided static implant planning programs include patient's digital files, identification, labeling, and segmentation of anatomical structures, mandibular nerve tracing, automatic implant placement, and surgical implant guide design.

Accuracy of a facebow record: A comparison between a conventional facebow and a smartphone 3D scanner

STATEMENT OF PROBLEM

Accurately transferring the maxillary cast to the articulator is an essential step in most prosthodontics procedures in both digital and conventional workflows. Recently, the use of a smartphone 3-dimensional (3D) scanner-based virtual facebow record has been reported, but its accuracy is unclear.

PURPOSE

The purpose of this clinical study was to compare the trueness and precision of a virtual facebow record made with a smartphone 3D scanner with that of a conventional facebow technique.

MATERIAL AND METHODS

One hundred facebow records were obtained from 10 participants using a virtual facebow record made with a smartphone 3D scanner (VFR_SP) and with a conventional facebow record (CFR) (n=10). In the VFR_SP group, a printed facebow fork was used to obtain virtual facebow records by using a smartphone-based face scanner. For the CFR group, an analog facebow record was obtained and scanned by using an industrial scanner. A cone beam computed tomography (CBCT) scan with an aligned maxillary arch scan was used as the control for each participant. Three reference points were placed on the maxillary arch scan on the right first molar, left central incisor, and left first molar. Scans from each group were superimposed on the CBCT scan to determine trueness. Scans within each group were also superimposed on each other to determine precision. Linear deviation at the 3 reference points and the angular deviation of occlusal planes were measured using a Python script. The trueness and precision of the 2 groups were compared by using a linear mixed model to account for repeated measures (α=.05).

RESULTS

No significant linear trueness differences between the 2 groups were found (P>.05). However, the VFR_SP group showed significantly less angular deviation: 1.53 degrees for the virtual facebow and 2.03 degrees for the conventional facebow group (P=.046). Regarding precision, the VFR_SP group showed significantly less linear deviation: 1.59 mm for the virtual facebow group and 2.33 mm for the conventional facebow group (P<.001), as well as angular deviation: 1.03 degrees for the virtual facebow group and 2.17 degrees for the conventional facebow (P<.001).

CONCLUSIONS

The VFR_SP group showed better accuracy compared with the CFR group. Further research with a larger sample size is needed.

True horizontal or gravity plane registration for transferring the maxillary scan into the virtual articulator by using a facial scanner without the need for an additional device

Different reference planes can be used to transfer the maxillary cast into the analog articulator, including the true horizontal or gravity reference plane. Different techniques have been described to record the gravity reference plane for transferring the maxillary scan into the virtual articulator by using facial scanning techniques. However, these digital facebow procedures require the use of an extraoral scan body system, printed reference device, or orientation reference board. This manuscript describes a technique for recording the gravity reference plane by using a facial scanner without the use of an additional device. This technique aims to reduce the clinical time needed to capture a patient's digital data and minimize the laboratory time needed to integrate the virtual patient and transfer the maxillary scan into the virtual articulator.

A Novel Approach of Surface Texture Mapping for Cone-Beam Computed Tomography in Image-Guided Surgical Navigation

The demand for cone-beam computed tomography (CBCT) imaging in clinics, particularly in dentistry, is rapidly increasing. Preoperative surgical planning is crucial to achieving desired treatment outcomes for imaging-guided surgical navigation. However, the lack of surface texture hinders effective communication between clinicians and patients, and the accuracy of superimposing a textured surface onto CBCT volume is limited by dissimilarity and registration based on facial features. To address these issues, this study presents a CBCT imaging system integrated with a monocular camera for reconstructing the texture surface by mapping it onto a 3D surface model created from CBCT images. The proposed method utilizes a geometric calibration tool for accurate mapping of the camera-visible surface with the mosaic texture. Additionally, a novel approach using 3D-2D feature mapping and surface parameterization technology is proposed for texture surface reconstruction. Experimental results, obtained from both real and simulation data, validate the effectiveness of the proposed approach with an error reduction to 0.32 mm and automated generation of integrated images. These findings demonstrate the robustness and high accuracy of our approach, improving the performance of texture mapping in CBCT imaging.

Creating a 3D diagnostic cast with realistic tooth shade and translucency using an open source nondental CAD software program: A dental technique

This article describes a digital technique for acquiring a 3-dimensional (3D) diagnostic cast with authentic tooth shade and translucency using an open source nondental computer-aided design (CAD) software program detailing the operational methods and parameters. The resultant 3D diagnostic cast can be transmitted to a dental laboratory for the fabrication of definitive prostheses.

Accuracy of the 3-dimensional virtual patient representation obtained by using 4 different techniques: An in vitro study

STATEMENT OF PROBLEM

Facial and intraoral scans can be aligned with or without the assistance of extraoral scan body systems to obtain a 3-dimensional (3D) virtual patient representation. However, the accuracy of the virtual patient remains uncertain.

PURPOSE

The purpose of this in vitro study was to measure the accuracy of the virtual patient representation obtained by superimposing facial and intraoral digital scans with 4 different techniques (with and without the usage of extraoral scan bodies) and to measure the operator influence on the accuracy of the virtual patient integration.

MATERIAL AND METHODS

Three markers were placed in the jaw simulation of a mannequin on the right (r), center (c), and left (l) surfaces. Five additional markers were attached to the mesiobuccal cusp of the right first molar (RM), cusp of the right canine (RC), buccal surface of the right central incisor (CI), cusp of the left canine (LC), and mesiobuccal cusp of the left first molar (LM). A reference scan (control scan) of the mannequin was obtained by using an industrial scanner (Gom ATOS Q 3D 12 M). Four different groups were created depending on the technique used: 3D scan body (3D scan body) (3D-SB group), AFT (AFT Dental System) (AFT group), Sat 3D (Sat 3D) (Sat3D group), and without using a scan body system (No-SB group). Additionally, a digital scan of the typodont was obtained with an intraoral scanner (TRIOS 4). The virtual patient integration was performed 10 times per group by 2 independent operators by using a software program (DentalCAD, Galway). Each operator obtained a total of 9 interlandmark measurements on the reference scan and on each virtual patient integration of each group with the measurement tool of the computer-aided design program. The data were analyzed by using 4-way ANOVA followed by the pairwise comparison Tukey tests (α=.05).

RESULTS

The group (P<.001), specimen (P<.001), and operator (P<.001) significantly influenced the trueness discrepancies obtained. Additionally, the 3D-SB group had the best trueness (244 μm), and the No-SB group had the worst trueness (346 μm). Operator 1 (279 μm) obtained significantly better trueness than operator 2 (295 μm). Group (P<.001), specimen (P<.001), and operator (P<.001) significantly influenced precision discrepancies, with the AFT (149 μm) and 3D-SB (154 μm) groups having the best precision and the No-SB group (269 μm) the worst precision. Operator 1 (176 μm) obtained significantly better precision than operator 2 (197 μm).

CONCLUSIONS

The techniques tested influenced the accuracy of the 3D virtual patient representation. The 3D-SB group had the best trueness, and the AFT and 3D-SB groups had the best precision, while the No-SB group showed the lowest trueness and precision values. Operator handling had a significant effect on the trueness and precision values of the virtual patient integrations tested.

Creating three-dimensional virtual patients by superimposing intraoral and facial digital scans guided with an aligner system: A dental technique

A technique for creating 3-dimensional virtual patients (3DVPs) by superimposing intraoral and facial digital scans guided with a novel aligner system is described. This aligner system supports design modifications to adapt to different facial scanning methods (FSMs) and reduce the impact of FSMs on the accuracy of 3DVPs. Two different designs of the aligner system are described: one for use with less-accurate FSMs and another for use with more-accurate FSMs. These virtual designs are available for download and use.

Scan body system to translate natural head position and virtual mounting into a 3-dimensional virtual patient: A dental technique

Various techniques have been developed for a 3-dimensional (3D) virtual patient. However, those techniques do not enable the registration of the alignment of the facial and intraoral digital scans, the registration for the mounting on the virtual articulator, and the integration of the natural head position (NHP) together. In the present manuscript, a scan body system is described that assists with the translation of the horizon orientation within the NHP of the patient into a computer-aided design software program. Additionally, the scan body system facilitates the facial and intraoral alignment, as well as the mounting of the maxillary virtual cast on the virtual articulator. This scan body system facilitates the integration of the 3D virtual patient and reduces chair and laboratory time.

Accuracy of the maxillary cast transfer into the virtual semi-adjustable articulator by using analog and digital facebow record methods

STATEMENT OF PROBLEM

Different digital methods have been described for transferring the maxillary cast into a virtual articulator; however, its accuracy remains uncertain.

PURPOSE

The purpose of this in vitro study was to compare the accuracy of the maxillary cast transfer into the virtual semi-adjustable articulator by using analog and digital methods.

MATERIAL AND METHODS

A maxillary typodont with 5 markers was positioned into a mannequin, which was digitized by using an industrial scanner (ATOS Q) and an extraoral scan of the typodont obtained (T710). Three groups were created based on the technique used to transfer the maxillary cast into the virtual articulator (Panadent PCH Articulator): conventional facebow record (CNV group), digital photograph (P group), and facial scanning (FS group) (n=10). In the CNV group, conventional facebow records (Kois Dentofacial analyzer system) were digitized (T710) and used to mount the maxillary scan into the articulator by aligning it with the reference platform (Kois adjustable platform) (DentalCAD). In the P group, photographs with the reference glasses (Kois Reference Glasses 3.0) were positioned in the mannequin. Each photograph was superimposed with the maxillary scan. Then, the maxillary scan was transferred into the virtual articulator by using the true horizontal plane information of the photograph. In the FS group, facial scans with an extraoral scan body (Kois Scan Body) were positioned in the mannequin by using a facial scanner (Instarisa). The extraoral scan body was digitized by using the same extraoral scanner. The digitized extraoral scan body provided the true horizontal plane information that was used to mount the maxillary scan into the articulator, along with the Kois disposable tray of the scan body. On the reference scan and each specimen, 15 linear measurements between the markers of the maxillary scans and the horizontal plane of the virtual articulator and 3 linear measurements between the maxillary dental midline and articulator midline were calculated. The measurements of the reference scan were used as a control to assess trueness and precision. Trueness was analyzed by using 1-way ANOVA followed by the pairwise comparison Tukey tests (α=.05). Precision was evaluated by using the Levene and pairwise comparisons Wilcoxon Rank sum tests.

RESULTS

No significant trueness (P=.996) or precision (P=.430) midline discrepancies were found. Significant posterior right (P<.001), anterior (P=.005), posterior left (P<.001), and overall (P<.001) trueness discrepancies were revealed among the groups. The P group obtained the best posterior right, posterior left, and overall trueness and precision. The P and FS groups demonstrated the best anterior trueness, but no anterior precision discrepancies were found.

CONCLUSIONS

The techniques tested affected the accuracy of the maxillary cast transfer into the virtual semi-adjustable articulator. In the majority of the parameters assessed, the photography method tested showed the best trueness and precision values. However, the maxillary cast transfer accuracy ranged from 137 ±44 µm to 453 ±176 µm among the techniques tested.

Facially driven guided crown lengthening using a complete digital workflow: A dental technique

A facially driven digital guided crown lengthening method using the virtual smile design approach supplemented with a static 3-dimensional face scan that demonstrates the digital data of extraoral soft tissue is presented. The technique enables the practitioner to virtually design the new smile and surgically plan the crown lengthening procedure.

Using an additively manufactured natural head position reference device to transfer the horizon orientation plane and integrate it with a 3-dimensional virtual patient: A dental technique

A virtual patient is obtained by aligning a patient's digital information, including facial and intraoral digital scans with or without hard tissue information from a cone beam computed tomography scan. However, while computer-aided design programs facilitate virtual patient integration, they do not provide a way to relate the horizon orientation with the patient's horizontal and vertical facial references. The present technique describes a way of relating the horizon orientation plane to the natural head position of the patient. An additively manufactured natural head position reference device was used to transfer the horizon orientation plane to the 3-dimensional virtual patient.

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

OBJECTIVE

Complete arch implant rehabilitation necessitates meticulous treatment planning and high-level collaboration between surgical and prosthetic dental teams. Emerging virtual technologies hold considerable promise in streamlining this process. The aim of this article is to extend recommendations to clinicians venturing into the virtual patient-assisted esthetic implant rehabilitation workflow.

OVERVIEW

This article summarizes recommendations for virtual patient-assisted esthetic implant rehabilitation in the following five aspects: three-dimensional data handling and superimposition, occlusion and virtual articulator integration in creating virtual patients, streamlined face- and prosthetic-driven surgical planning, reuse of presurgical data ("Copy & Paste"), and final impression for passive fitting of final restoration. To illustrate these principles, a case with complete-mouth implant rehabilitation completed within six visits using this virtual patient workflow is presented.

CONCLUSION

The virtual patient workflow serves as an invaluable tool to perform treatment planning, enhance efficiency, and ensure predictable outcomes in esthetic complete arch implant rehabilitation.

CLINICAL SIGNIFICANCE

Virtual workflows are increasingly prevalent in esthetic implant rehabilitation. Nevertheless, these workflows necessitate a distinct set of knowledge and tools divergent from conventional dentistry practices. This article offers guidelines and recommendations for dental clinicians who are new to this field.

Analysis of the impact of the facial scanning method on the precision of a virtual facebow record technique: An in vivo study

STATEMENT OF PROBLEM

Virtual facebow record techniques typically record the relationship of a maxillary digital scan to facial landmarks by aligning it to a 3-dimensional face scan. Three-dimensional face scans can be acquired with different facial scanning methods, but the impact of the facial scanning method on the accuracy (trueness and precision) of a virtual facebow record technique remains unclear.

PURPOSE

The purpose of this in vivo study was to assess the impact of the facial scanning method on the precision under the repeatability conditions (repeatability) of a virtual facebow record technique.

MATERIAL AND METHODS

Repeatability of the virtual facebow record technique with the following 3 clinical-grade facial scanning methods was determined and compared: a professional handheld scanner based on structured blue light scanning technology (PHS method); an attachment-type 3-dimensional sensor camera connected to a tablet and controlled with a mobile application (3DSC-T method); and a smartphone with an integrated 3-dimensional sensor camera controlled with a mobile application (3DSC-S method). To determine the repeatability of the virtual facebow record technique with each facial scanning method, 8 virtual facebow records of a completely dentate adult with class I occlusion and mesoprosopic facial form were obtained (8×3=24 in total); with these, 8 locations of a maxillary digital scan with respect to a common 3-dimensional face scan were obtained. Repeatability was determined in terms of deviations between located maxillary digital scans, determined, in turn, by calculating the distances between corresponding vertices for each of the possible nonrepeating combinations of pairs of located maxillary digital scans (8C2=28). Finally, the repeatability of the virtual facebow record technique with the different facial scanning methods was compared by using the Welch ANOVA test and the post hoc Games-Howell test (both α=.05).

RESULTS

The repeatability of the virtual facebow record technique with PHS, 3DSC-T, and 3DSC-S facial scanning methods resulted in 0.243 ±0.094 mm, 0.437 ±0.171 mm, and 1.023 ±0.399 mm, respectively. Comparison of these results revealed that the facial scanning method had a statistically significant effect on the repeatability of the virtual facebow record technique (P<.001) and that its repeatability was statistically significantly greater with the PHS facial scanning method than with the 3DSC-T and 3DSC-S facial scanning methods and greater with the 3DSC-T facial scanning method than with the 3DSC-S facial scanning method (P<.001 for all pairwise comparisons).

CONCLUSIONS

This study found that the facial scanning method had a great impact on the repeatability of the virtual facebow record technique and that the virtual facebow record technique was more repeatable with more accurate facial scanning methods.

Pre-orthodontic restorative treatment of microdontia diastema teeth using composite injection technique with a digital workflow-Case report

Restorative treatment of microdontia teeth is often considered as the final step of post-orthodontic treatment. Based on digital workflow, this clinical report presents pre-orthodontic reshaping of anterior teeth in the smile disharmony of a young patient using bilayering composite injection technique. Transparent silicone indexes for dentin and enamel fillings were fabricated from three-dimensional-printed models of the digital wax-up. This noninvasive, simple and straightforward injection technique was able to provide semipermanent reversible aesthetic restorations while awaiting for adulthood and definitive prosthodontic solution. Closure of diastemas before orthodontic treatment were carried out to restore functional contact point and to guide future teeth movements.

Prevention of peri-implant disease in edentulous patients with fixed implant rehabilitations

OBJECTIVES

To provide an overview about the current approaches to prevent peri-implant diseases in edentulous patients with complete-arch implant-supported prostheses, and to review the clinical applications of the latest digital technologies for implant prosthodontics.

METHODS

A review of the guidelines to prevent peri-implant diseases in patient's receiving complete-arch implant-supported prostheses including facially driven treatment planning procedures using either conventional or digital methods, computer-aided implant planning procedures, and prosthodontic design variables including the optimal number and distribution of dental implants, implant to abutment connection type, implant or abutment level design, screw- or cement-retained alternatives, prostheses contours, and material selection is provided. Furthermore, an outline of the current therapeutic management approaches to address peri-implant diseases is reviewed.

CONCLUSIONS

Clinicians should understand and know different planning and design-related variables that can affect biological and mechanical complication rates of complete-arch implant-supported prostheses. Maintenance protocols are fundamental for minimizing biological and mechanical complications.

A complete digital approach for facially generated full arch diagnostic wax up, guided surgery, and implant-supported interim prosthesis by integrating 3D facial scanning, intraoral scan and CBCT

Continuous innovation in digital dental technology offers new prospects for creating a complete virtual environment. The technique described adds a facial approach to the conventional digital workflow by incorporating 3D face scans to cone beam computed tomography and intraoral scans. Using this workflow, clinicians can obtain a complete virtual patient for facially generated diagnostic wax up and plan and implement a predictable implant placement and interim prosthesis. This technique provides a full digital workflow for restoratively-driven computer-aided implant planning, guided surgery, and 3D printing of an interim complete-arch fixed implant-supported prosthesis.

Accuracy of RGB-D camera-based and stereophotogrammetric facial scanners: a comparative study

OBJECTIVES

This study aimed to evaluate and compare the accuracy and inter-operator reliability of a low-cost red-green-blue-depth (RGB-D) camera-based facial scanner (Bellus3D Arc7) with a stereophotogrammetry facial scanner (3dMD) and to explore the possibility of the former as a clinical substitute for the latter.

METHODS

A mannequin head was selected as the research object. In the RGB-D camera-based facial scanner group, the head was continuously scanned five times using an RGB-D camera-based facial scanner (Bellus3D Arc7), and the outcome data of each scan was then imported into CAD software (MeshLab) to reconstruct three-dimensional (3D) facial photographs. In the stereophotogrammetry facial scanner group, the mannequin head was scanned with a stereophotogrammetry facial scanner (3dMD). Selected parameters were directly measured on the reconstructed 3D virtual faces using a CAD software. The same parameters were then measured directly on the mannequin head using the direct anthropometry (DA) method as the gold standard for later comparison. The accuracy of the facial scanners was evaluated in terms of trueness and precision. Trueness was evaluated by comparing the measurement results of the two groups with each other and with that of DA using equivalence tests and average absolute deviations, while precision and inter-operator reliability were assessed using the intraclass correlation coefficient (ICC). A 3D facial mesh deviation between the two groups was also calculated for further reference using a 3D metrology software (GOM inspect pro).

RESULTS

In terms of trueness, the average absolute deviations between RGB-D camera-based and stereophotogrammetry facial scanners, between RGB-D camera-based facial scanner and DA, and between stereophotogrammetry facial scanner and DA were statistically equivalent at 0.50±0.27 mm, 0.61±0.42 mm, and 0.28±0.14 mm, respectively. Equivalence test results confirmed that their equivalence was within clinical requirements (<1 mm). The ICC for each parameter was approximately 0.999 in terms of precision and inter-operator reliability. A 3D facial mesh analysis suggested that the deviation between the two groups was 0.37±0.01 mm.

CONCLUSIONS

For facial scanners, an accuracy of <1 mm is commonly considered clinically acceptable. Both the RGB-D camera-based and stereophotogrammetry facial scanners in this study showed acceptable trueness, high precision, and inter-operator reliability. A low-cost RGB-D camera-based facial scanner could be an eligible clinical substitute for traditional stereophotogrammetry.

CLINICAL SIGNIFICANCE

The low-cost RGB-D camera-based facial scanner showed clinically acceptable trueness, high precision, and inter-operator reliability; thus, it could be an eligible clinical substitute for traditional stereophotogrammetry.

Smartphone-Based Facial Scanning as a Viable Tool for Facially Driven Orthodontics?

The current paradigm shift in orthodontic treatment planning is based on facially driven diagnostics. This requires an affordable, convenient, and non-invasive solution for face scanning. Therefore, utilization of smartphones' TrueDepth sensors is very tempting. TrueDepth refers to front-facing cameras with a dot projector in Apple devices that provide real-time depth data in addition to visual information. There are several applications that tout themselves as accurate solutions for 3D scanning of the face in dentistry. Their clinical accuracy has been uncertain. This study focuses on evaluating the accuracy of the Bellus3D Dental Pro app, which uses Apple's TrueDepth sensor. The app reconstructs a virtual, high-resolution version of the face, which is available for download as a 3D object. In this paper, sixty TrueDepth scans of the face were compared to sixty corresponding facial surfaces segmented from CBCT. Difference maps were created for each pair and evaluated in specific facial regions. The results confirmed statistically significant differences in some facial regions with amplitudes greater than 3 mm, suggesting that current technology has limited applicability for clinical use. The clinical utilization of facial scanning for orthodontic evaluation, which does not require accuracy in the lip region below 3 mm, can be considered.

Additively Manufactured Scan Bodies for Virtual Patient Integration: Different Designs, Manufacturing Procedures, and Clinical Protocols

Additively manufactured intraoral scan bodies can be used to guide the alignment of a patient's digital file information, including facial and intraoral digital scans both with and without a cone beam computed tomography scan, and to obtain a 3D virtual patient's representation. The present manuscript reviews the different intraoral scan body designs, procedures involved in additive manufacturing, clinical protocols for fabricating an additively manufactured scan body, performing a patient's digital data collection, and completing the alignment techniques.

Digital to Analog Facially Generated Interchangeable Facebow Transfer: Capturing a Standardized Reference Position

Although the evolution of digital technology continues to improve patient data acquisition, the ability to both standardize the recording of the maxillary occlusal plane and capture the necessary dynamic data for dento-facial analysis remains elusive. This article describes step-by-step techniques to position the maxilla on an articulator using the natural head position and a facial reference system (Kois Facial Reference Glasses) for both analog and digital workflows. A photographic technique will be presented that captures the natural head position and allows the clinician to align a 2D reference photograph with the maxillary intraoral digital scan and the virtual articulator. Using this reference photograph, the clinician can record and communicate to the technician the maxillary arch position in relationship with the facial references, as well as transfer the additively manufactured casts in the same facial orientation for mounting and analysis either virtually or on an analog articulator. This article is protected by copyright. All rights reserved.