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Incorporating a facial scanner into the digital workflow: A dental technique
DENTAL TECHNIQUE
Incorporating a facial scanner into the digital workflow: A dental technique Stefano Granata, DDS,a Lorenzo Giberti, ODT,b Paolo Vigolo, DMD, MSD,c Edoardo Stellini, DDS,d and Adolfo Di Fiore, DDS, PhDe Computer-aided design and ABSTRACT computer-aided manufacturing The transfer of extraoral and intraoral clinical information into the virtual environment is necessary (CAD-CAM) systems have to optimize prosthetic treatment planning. The purpose of this article was to describe a digital simplified prosthetic steps workflow designed to superimpose the different 3D files obtained with an intraoral scanner, a and reduced clinical treatcone bean computed tomography (CBCT) device, and a facial scanner and their clinical ment times.1,2 Intraoral application with the Digital bite device. (J Prosthet Dent 2019;-:---) scanners (IOSs), cone bean computed tomography (CBCT) devices, photography, TECHNIQUE and digital trial restorations are used to create a virtual To demonstrate the technique, a patient without facial patient.3 However, the orientation of the maxilla in deformities who had been planned for treatment with an 4 the 3D space according to facial lines is still a difficult implant-supported fixed dental prosthesis in the edenprocedure. Several computerized facebow transfer tulous maxilla was selected. systems are available to record the occlusal plane, but 5 they are expensive and complex to operate. Recently, 1. Use the DGB to match all the files. The DGB a facial scanner (FS) was introduced into digital consisted of 2 components called DGB1 and DGB2. dentistry to scan extraoral structures. Different DGB1 is a device with an occlusal base, in which 2 smartphone applications are available that can be types of landmarks are inserted (Figs. 1, 2). The used to orient the maxilla in a virtual environment first landmark is represented by radiopaque according to the facial lines. The purpose of this article spheres, placed in strategic areas in the arch of the was to describe a digital workflow for the superimDGB1, to be recognized during the radiographic position of different 3D patient data files through a acquisition of the patient. The DGB1 material is a geometric occlusal registration prototype device resin for printing 3D models (Shera; Shera (DGB) (Digitalbite; Digitalsmile srl). With this workWerkstoff-Technologie GmbH). The second landflow, the clinician can match different files from IOS, mark of the DGB1 is represented by a base inspired CBCT, and FS in computer-aided implant software by a Lego brick (Lego Group) with recognizable and in CAD-CAM dental systems, identify occlusal shape and landmarks during digital scans with the planes, reference points, lines, angles for facial analvarious instruments. Stabilize the DGB1 by using a ysis, and digital wax patterns, and transfer 3D data to polyether impression material (Ramitec; 3M) on printed casts in a semiadjustable articulator with a the maxillary arch to superimpose the files. The facebow. DGB1 is equipped with an attachment compatible
a
Resident, Department of Neuroscience, School of Dentistry, University of Padova, Padova, Italy; Private practice, Modena, Italy. Private practive, Bologna, Italy. Adjunct Professor, Department of Neuroscience, School of Dentistry, University of Padova, Padova, Italy. d Full Professor and Head of Dental Clinic and School of Dentistry, Department of Neuroscience, University of Padova, Padova, Italy. e Adjunct Professor, Department of Neuroscience, School of Dentistry, University of Padova, Padova, Italy. b c
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Figure 1. First component (DGB1) of geometric occlusal registration prototype device (DGB). A, DGB1, geometric, and radiopaque reference spheres. B, DGB1 and facebow record attached to maxilla with polyether impression material.
with various traditional facebow transfer devices. The second component of the DGB is called DGB2 and consists of a device of the same material as DGB1, in the shape of a straight parallelepiped and with recognizable points as landmarks. Apply double-sided adhesive tape (Softleaves MD Body Tapes) on the DGB2. Attach the DGB2 to the patient’s forehead and make all the registrations in a single session with the device in the same position (Fig. 2). 3. Arrange the patient in a chair with head upright and eyes looking toward the horizon (Frankfurt plane) to record the face texture with a facial scanner (Bellus3D; Bellus3D Inc) connected to a personal computer. Place the face of the patient at about 30 to 45 cm from the scanner, in accordance with the recommendations of the manufacturer. Instruct the patient to maintain the pose with unchanged gestures during the recording phases. Record 3 different steps: face with maximum smile, face with DGB1 in position, and face with mouth open and maximum intercuspation position. Use the DGB2 in the same way in all 3 poses (Fig. 3). Remove the DGB2 at the end of the session, but if another registration is needed, the entire procedure must be repeated. Use the DGB1 device to merge the object file (OBJ) with the intraoral digital scan (or scanned from a conventional impression) instead of the DGB2 for the superimposition of the 3 poses in a single session. An OBJ file is a format used to define geometry and other properties of graphic objects. Using this format, all the information for the definition of lines, polygons, curves, and freeform surfaces could be listed. THE JOURNAL OF PROSTHETIC DENTISTRY
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Figure 2. Second component (DGB2) of geometric occlusal registration prototype device (DGB). A, DGB2 device. B, DGB2 and 3 recorded poses.
Figure 3. DGB (DGB 1 and 2) in situ for facial scanner. A, Best fit lateral view DGB1, DGB2, and OBJ file. B, Frontal view. DGB, geometric occlusal registration prototype device; OBJ, object file.
4. Record a digital intraoral scan (CS3600; Carestream). Set the scanner to the orthodontics mode, according to the manufacturer’s recommendations. Export the original CSZ file with the same software in a polygon file format (PLY) or in a standard tessellation language (STL) file. The PLY file is a format similar to the STL file, but it also contains surface color data. 5. Make a CBCT (CS9300; Carestream) with DGB1 on the maxillary arch by using a polyether impression material (Ramitec; 3M). 6. Scan the DGB1 devices with a laboratory scanner (InEosXs; Dentsply Sirona). Load all the OBJ (Facial Scanner), DCM (CBCT), STL (DGB1), and PLY (intraoral scanner) files into 3D-guided surgery planning software (DDS-Pro; Dentalica Spa). The same data, except for the DCM file, could be loaded into CAD design software (Exocad; Exocad GmbH) for prosthetic virtual planning. Superimpose Granata et al
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Figure 4. Matching of files obtained from intraoral scanner and CBCT device in computer-aided implant software. Step 1: matching to DCM file. A, Initial digital cast. B, Digital cast and wax pattern. C, Digital cast, wax pattern, and DCM file (transparent). D, Prosthetic guided implant planning. E, Matching digital scan to DCM file. F, OBJ file matched to DCM file, implant plan, and digital scans. CBCT, cone bean computed tomography; DCM, Digital Imaging and Communications in Medicine file; OBJ, object file.
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Figure 5. Matching files obtained from CBCT device, intraoral scanner, and facial scanner in computer-aided implant software. Step 2: A, PLY files matched to DCM file. B, OBJ file aligned to digital scans and DCM file. CBCT, cone bean computed tomography; DCM, Digital Imaging and Communications in Medicine file; OBJ, object file; PLY, polygon file format.
according to the reference point, merge a minimum of 3 items per object, and apply a best-fitting algorithm (Figs. 3-6). DISCUSSION This article introduced a digital workflow technique to record the facial lines used to transfer the 3D position of the maxilla into a virtual environment. The facial scanner (OBJ file) allowed different expressions of the patient smile to be uploaded and the virtual wax pattern to be evaluated in the rest vertical dimension, in the slight and maximum smile (E phoneme), and more reference skin points. An article has described a methodology for transferring the data of the maxillary arch position into a virtual articulator without the use of a facial scanner.5 The authors used 3 adhesive targets on the patient’s head and a facebow fork as reference points and made 10 photographs in different positions with a digital camera. All the pictures were superimposed by using reverse engineering software. The reference points between the patient’s face and the dentolabial relationships could be established with 2D and 3D images; however, both systems showed evaluation errors, and the 3D images were considered preferable.6 A few articles have described the use of a facial scanner (FS). Matsuoka et al7 used an FS to develop 3D facial expression models to fabricate a facial prosthesis. Kim et al8 matched the STL files of casts obtained with a desktop scanner and the jaw movements recorded with a face scanner to perform occlusion analysis. However, the authors did not evaluate the DCM files Granata et al
Figure 6. Matching of all files obtained from intraoral scanner, CBCT device, and facial scanner in computer-aided implant software. Step 3: A, Maxillary cast and mandibular digital scan. B, Maxillary cast, wax pattern, and mandibular digital scan. C, DGB1, wax pattern, and mandibular digital scan combined. D, Implant planning and maximum intercuspation of wax pattern with mandibular digital scan. CBCT, cone bean computed tomography; DGB, geometric occlusal registration prototype device.
and matched only the STL and OBJ files without a reference system. One article described a technique similar to the one presented in the present article.9 The THE JOURNAL OF PROSTHETIC DENTISTRY
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Figure 7. Reference points and lines on sagittal plane obtained by facial scan. A, Rickets line, nasiolabial angle. B, Frankfurt and Camper planes.
authors used 2 mandibular disposable impression trays to build the virtual facebow using Lego bricks. This device was used to match the different facial scan images with digital impressions and to build the virtual patient model. Moreover, the authors described only the possible comparison of the resulting virtual patient model with a full-face CBCT scan. The DGB is an inexpensive geometric occlusal registration prototype device designed as a reference system to superimpose all 3D image files into a 3Dguided surgery planning software or CAD design software. The OBJ file gives more indications for esthetic analysis in the dental laboratory but did not offer detailed 3D information on the patient’s dentition. With the DGB, all files (DCM, STL/PLY, and OBJ) were matched using the radiopaque landmark points and geometric reference. It was also possible to superimpose a completely edentulous maxilla in the absence of other reference points. With this digital workflow, a new way of working has been introduced. It was possible to get the reference points, the angles, and the planes that can be easily identified on the skin (OBJ) or skull (DCM) point reference, such as the Camper plane (tragus-wing line of the nose), the Frankfurt plane (tragus-infraorbital point line), the horizontal lines (such as oral line, bipupillar line, commissure line), the vertical lines (midline, interalar line), the esthetic lines (Ricketts line), and the angular measures (nasolabial angle, face convexity) (Figs. 7, 8). An additional advantage of the DGB is the possibility of connecting with a traditional facebow; therefore, the patient’s casts (in gypsum or 3D prototypes) could be assembled in a semiadjustable articulator system (Fig. 1). This characteristic allows the evaluation of physical casts for complex clinical treatments by
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Figure 8. Reference points and lines on frontal plane obtained by facial scan. A, Horizontal lines. B, Vertical lines.
assessing emergence profiles, interproximal and occlusal contacts, and the application of the ceramic material. The distortion caused by the processing of the original files and the matching method may be a problem. The DCM files have an average linear distortion of about 200 mm,10 and the OBJ files may have average distortions of 500 mm, with wide oscillations ranging between 140 and 1330 mm,7 which depends on the detection method and the type of scanner used.11 However, the superimposition of these files manually is impossible without clinically unacceptable distortions. Research is needed to understand the performance of the facial scanner and the accuracy of this digital workflow. SUMMARY A new digital methodology was described for the superimposition of different 3D files (STL, OBJ, and DCM) in the virtual environment (3D-guided surgery planning software or CAD design software) by using an inexpensive geometric occlusal device. The DGB could be connected with a traditional facebow transfer to change the workflow from digital to traditional. REFERENCES 1. Alghazzawi TF. Advancements in CAD/CAM technology: options for practical implementation. J Prosthodont Res 2016;60:72-84. 2. Di Fiore A, Vigolo P, Graiff L, Stellini E. Digital vs conventional workflow for screw-retained single-implant crowns: a comparison of key considerations. Int J Prosthodont 2018;31:577-9. 3. Joda T, Gallucci GO. The virtual patient in dental medicine. Clin Oral Implants Res 2015;26:725-6. 4. Fradeani M. Esthetic analysis: a systematic approach to prosthetic treatment. Hanover Park: Quintessence Publishing Co; 2004. p. 36-49. 5. Solaberrieta E, Garmendia A, Minguez R, Brizuela A, Pradies G. Virtual facebow technique. J Prosthet Dent 2015;114:751-5. 6. Bohner L, Gamba DD, Hanisch M, Marcio BS, Tortamano Neto P, Laganá DC, et al. Accuracy of digital technologies for the scanning of facial,
Granata et al
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8.
9. 10.
skeletal, and intraoral tissues: A systematic review. J Prosthet Dent 2019;121: 246-51. Matsuoka A, Yoshioka F, Ozawa S, Takebe J. Development of three-dimensional facial expression models using morphing methods for fabricating facial prostheses. J Prosthodont Res 2019;63: 66-72. Kim JE, Park JH, Moon HS, Shim JS. Complete assessment of occlusal dynamics and establishment of a digital workflow by using target tracking with a three-dimensional facial scanner. J Prosthodont Res 2019;63:120-4. Lam WY, Hsung RT, Choi WW, Luk HW, Pow EH. A 2-part facebow for CAD-CAM dentistry. J Prosthet Dent 2016;116:843-7. Jacobs R, Salmon B, Codari M, Hassan B, Bornstein MM. Cone beam computed tomography in implant dentistry: recommendations for clinical use. BMC Oral Health 2018;18:88.
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11. Zhao YJ, Xiong YX, Wang Y. Three-dimensional accuracy of facial scan for facial deformities in clinics: a new evaluation method for facial scanner accuracy. PLoS One 2017;12:e0169402. Corresponding author: Dr Adolfo Di Fiore Department of Neuroscience, Dental School University of Padova, via Giustiniani 2 35100 Padova ITALY Email: adolfo.difi[email protected] Copyright © 2019 by the Editorial Council for The Journal of Prosthetic Dentistry. https://doi.org/10.1016/j.prosdent.2019.05.021
THE JOURNAL OF PROSTHETIC DENTISTRY
Incorporating a facial scanner into the digital workflow: A dental technique Stefano Granata, DDS,a Lorenzo Giberti, ODT,b Paolo Vigolo, DMD, MSD,c Edoardo Stellini, DDS,d and Adolfo Di Fiore, DDS, PhDe Computer-aided design and ABSTRACT computer-aided manufacturing The transfer of extraoral and intraoral clinical information into the virtual environment is necessary (CAD-CAM) systems have to optimize prosthetic treatment planning. The purpose of this article was to describe a digital simplified prosthetic steps workflow designed to superimpose the different 3D files obtained with an intraoral scanner, a and reduced clinical treatcone bean computed tomography (CBCT) device, and a facial scanner and their clinical ment times.1,2 Intraoral application with the Digital bite device. (J Prosthet Dent 2019;-:---) scanners (IOSs), cone bean computed tomography (CBCT) devices, photography, TECHNIQUE and digital trial restorations are used to create a virtual To demonstrate the technique, a patient without facial patient.3 However, the orientation of the maxilla in deformities who had been planned for treatment with an 4 the 3D space according to facial lines is still a difficult implant-supported fixed dental prosthesis in the edenprocedure. Several computerized facebow transfer tulous maxilla was selected. systems are available to record the occlusal plane, but 5 they are expensive and complex to operate. Recently, 1. Use the DGB to match all the files. The DGB a facial scanner (FS) was introduced into digital consisted of 2 components called DGB1 and DGB2. dentistry to scan extraoral structures. Different DGB1 is a device with an occlusal base, in which 2 smartphone applications are available that can be types of landmarks are inserted (Figs. 1, 2). The used to orient the maxilla in a virtual environment first landmark is represented by radiopaque according to the facial lines. The purpose of this article spheres, placed in strategic areas in the arch of the was to describe a digital workflow for the superimDGB1, to be recognized during the radiographic position of different 3D patient data files through a acquisition of the patient. The DGB1 material is a geometric occlusal registration prototype device resin for printing 3D models (Shera; Shera (DGB) (Digitalbite; Digitalsmile srl). With this workWerkstoff-Technologie GmbH). The second landflow, the clinician can match different files from IOS, mark of the DGB1 is represented by a base inspired CBCT, and FS in computer-aided implant software by a Lego brick (Lego Group) with recognizable and in CAD-CAM dental systems, identify occlusal shape and landmarks during digital scans with the planes, reference points, lines, angles for facial analvarious instruments. Stabilize the DGB1 by using a ysis, and digital wax patterns, and transfer 3D data to polyether impression material (Ramitec; 3M) on printed casts in a semiadjustable articulator with a the maxillary arch to superimpose the files. The facebow. DGB1 is equipped with an attachment compatible
a
Resident, Department of Neuroscience, School of Dentistry, University of Padova, Padova, Italy; Private practice, Modena, Italy. Private practive, Bologna, Italy. Adjunct Professor, Department of Neuroscience, School of Dentistry, University of Padova, Padova, Italy. d Full Professor and Head of Dental Clinic and School of Dentistry, Department of Neuroscience, University of Padova, Padova, Italy. e Adjunct Professor, Department of Neuroscience, School of Dentistry, University of Padova, Padova, Italy. b c
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Figure 1. First component (DGB1) of geometric occlusal registration prototype device (DGB). A, DGB1, geometric, and radiopaque reference spheres. B, DGB1 and facebow record attached to maxilla with polyether impression material.
with various traditional facebow transfer devices. The second component of the DGB is called DGB2 and consists of a device of the same material as DGB1, in the shape of a straight parallelepiped and with recognizable points as landmarks. Apply double-sided adhesive tape (Softleaves MD Body Tapes) on the DGB2. Attach the DGB2 to the patient’s forehead and make all the registrations in a single session with the device in the same position (Fig. 2). 3. Arrange the patient in a chair with head upright and eyes looking toward the horizon (Frankfurt plane) to record the face texture with a facial scanner (Bellus3D; Bellus3D Inc) connected to a personal computer. Place the face of the patient at about 30 to 45 cm from the scanner, in accordance with the recommendations of the manufacturer. Instruct the patient to maintain the pose with unchanged gestures during the recording phases. Record 3 different steps: face with maximum smile, face with DGB1 in position, and face with mouth open and maximum intercuspation position. Use the DGB2 in the same way in all 3 poses (Fig. 3). Remove the DGB2 at the end of the session, but if another registration is needed, the entire procedure must be repeated. Use the DGB1 device to merge the object file (OBJ) with the intraoral digital scan (or scanned from a conventional impression) instead of the DGB2 for the superimposition of the 3 poses in a single session. An OBJ file is a format used to define geometry and other properties of graphic objects. Using this format, all the information for the definition of lines, polygons, curves, and freeform surfaces could be listed. THE JOURNAL OF PROSTHETIC DENTISTRY
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Figure 2. Second component (DGB2) of geometric occlusal registration prototype device (DGB). A, DGB2 device. B, DGB2 and 3 recorded poses.
Figure 3. DGB (DGB 1 and 2) in situ for facial scanner. A, Best fit lateral view DGB1, DGB2, and OBJ file. B, Frontal view. DGB, geometric occlusal registration prototype device; OBJ, object file.
4. Record a digital intraoral scan (CS3600; Carestream). Set the scanner to the orthodontics mode, according to the manufacturer’s recommendations. Export the original CSZ file with the same software in a polygon file format (PLY) or in a standard tessellation language (STL) file. The PLY file is a format similar to the STL file, but it also contains surface color data. 5. Make a CBCT (CS9300; Carestream) with DGB1 on the maxillary arch by using a polyether impression material (Ramitec; 3M). 6. Scan the DGB1 devices with a laboratory scanner (InEosXs; Dentsply Sirona). Load all the OBJ (Facial Scanner), DCM (CBCT), STL (DGB1), and PLY (intraoral scanner) files into 3D-guided surgery planning software (DDS-Pro; Dentalica Spa). The same data, except for the DCM file, could be loaded into CAD design software (Exocad; Exocad GmbH) for prosthetic virtual planning. Superimpose Granata et al
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Figure 4. Matching of files obtained from intraoral scanner and CBCT device in computer-aided implant software. Step 1: matching to DCM file. A, Initial digital cast. B, Digital cast and wax pattern. C, Digital cast, wax pattern, and DCM file (transparent). D, Prosthetic guided implant planning. E, Matching digital scan to DCM file. F, OBJ file matched to DCM file, implant plan, and digital scans. CBCT, cone bean computed tomography; DCM, Digital Imaging and Communications in Medicine file; OBJ, object file.
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Figure 5. Matching files obtained from CBCT device, intraoral scanner, and facial scanner in computer-aided implant software. Step 2: A, PLY files matched to DCM file. B, OBJ file aligned to digital scans and DCM file. CBCT, cone bean computed tomography; DCM, Digital Imaging and Communications in Medicine file; OBJ, object file; PLY, polygon file format.
according to the reference point, merge a minimum of 3 items per object, and apply a best-fitting algorithm (Figs. 3-6). DISCUSSION This article introduced a digital workflow technique to record the facial lines used to transfer the 3D position of the maxilla into a virtual environment. The facial scanner (OBJ file) allowed different expressions of the patient smile to be uploaded and the virtual wax pattern to be evaluated in the rest vertical dimension, in the slight and maximum smile (E phoneme), and more reference skin points. An article has described a methodology for transferring the data of the maxillary arch position into a virtual articulator without the use of a facial scanner.5 The authors used 3 adhesive targets on the patient’s head and a facebow fork as reference points and made 10 photographs in different positions with a digital camera. All the pictures were superimposed by using reverse engineering software. The reference points between the patient’s face and the dentolabial relationships could be established with 2D and 3D images; however, both systems showed evaluation errors, and the 3D images were considered preferable.6 A few articles have described the use of a facial scanner (FS). Matsuoka et al7 used an FS to develop 3D facial expression models to fabricate a facial prosthesis. Kim et al8 matched the STL files of casts obtained with a desktop scanner and the jaw movements recorded with a face scanner to perform occlusion analysis. However, the authors did not evaluate the DCM files Granata et al
Figure 6. Matching of all files obtained from intraoral scanner, CBCT device, and facial scanner in computer-aided implant software. Step 3: A, Maxillary cast and mandibular digital scan. B, Maxillary cast, wax pattern, and mandibular digital scan. C, DGB1, wax pattern, and mandibular digital scan combined. D, Implant planning and maximum intercuspation of wax pattern with mandibular digital scan. CBCT, cone bean computed tomography; DGB, geometric occlusal registration prototype device.
and matched only the STL and OBJ files without a reference system. One article described a technique similar to the one presented in the present article.9 The THE JOURNAL OF PROSTHETIC DENTISTRY
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Figure 7. Reference points and lines on sagittal plane obtained by facial scan. A, Rickets line, nasiolabial angle. B, Frankfurt and Camper planes.
authors used 2 mandibular disposable impression trays to build the virtual facebow using Lego bricks. This device was used to match the different facial scan images with digital impressions and to build the virtual patient model. Moreover, the authors described only the possible comparison of the resulting virtual patient model with a full-face CBCT scan. The DGB is an inexpensive geometric occlusal registration prototype device designed as a reference system to superimpose all 3D image files into a 3Dguided surgery planning software or CAD design software. The OBJ file gives more indications for esthetic analysis in the dental laboratory but did not offer detailed 3D information on the patient’s dentition. With the DGB, all files (DCM, STL/PLY, and OBJ) were matched using the radiopaque landmark points and geometric reference. It was also possible to superimpose a completely edentulous maxilla in the absence of other reference points. With this digital workflow, a new way of working has been introduced. It was possible to get the reference points, the angles, and the planes that can be easily identified on the skin (OBJ) or skull (DCM) point reference, such as the Camper plane (tragus-wing line of the nose), the Frankfurt plane (tragus-infraorbital point line), the horizontal lines (such as oral line, bipupillar line, commissure line), the vertical lines (midline, interalar line), the esthetic lines (Ricketts line), and the angular measures (nasolabial angle, face convexity) (Figs. 7, 8). An additional advantage of the DGB is the possibility of connecting with a traditional facebow; therefore, the patient’s casts (in gypsum or 3D prototypes) could be assembled in a semiadjustable articulator system (Fig. 1). This characteristic allows the evaluation of physical casts for complex clinical treatments by
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Figure 8. Reference points and lines on frontal plane obtained by facial scan. A, Horizontal lines. B, Vertical lines.
assessing emergence profiles, interproximal and occlusal contacts, and the application of the ceramic material. The distortion caused by the processing of the original files and the matching method may be a problem. The DCM files have an average linear distortion of about 200 mm,10 and the OBJ files may have average distortions of 500 mm, with wide oscillations ranging between 140 and 1330 mm,7 which depends on the detection method and the type of scanner used.11 However, the superimposition of these files manually is impossible without clinically unacceptable distortions. Research is needed to understand the performance of the facial scanner and the accuracy of this digital workflow. SUMMARY A new digital methodology was described for the superimposition of different 3D files (STL, OBJ, and DCM) in the virtual environment (3D-guided surgery planning software or CAD design software) by using an inexpensive geometric occlusal device. The DGB could be connected with a traditional facebow transfer to change the workflow from digital to traditional. REFERENCES 1. Alghazzawi TF. Advancements in CAD/CAM technology: options for practical implementation. J Prosthodont Res 2016;60:72-84. 2. Di Fiore A, Vigolo P, Graiff L, Stellini E. Digital vs conventional workflow for screw-retained single-implant crowns: a comparison of key considerations. Int J Prosthodont 2018;31:577-9. 3. Joda T, Gallucci GO. The virtual patient in dental medicine. Clin Oral Implants Res 2015;26:725-6. 4. Fradeani M. Esthetic analysis: a systematic approach to prosthetic treatment. Hanover Park: Quintessence Publishing Co; 2004. p. 36-49. 5. Solaberrieta E, Garmendia A, Minguez R, Brizuela A, Pradies G. Virtual facebow technique. J Prosthet Dent 2015;114:751-5. 6. Bohner L, Gamba DD, Hanisch M, Marcio BS, Tortamano Neto P, Laganá DC, et al. Accuracy of digital technologies for the scanning of facial,
Granata et al
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2019
7.
8.
9. 10.
skeletal, and intraoral tissues: A systematic review. J Prosthet Dent 2019;121: 246-51. Matsuoka A, Yoshioka F, Ozawa S, Takebe J. Development of three-dimensional facial expression models using morphing methods for fabricating facial prostheses. J Prosthodont Res 2019;63: 66-72. Kim JE, Park JH, Moon HS, Shim JS. Complete assessment of occlusal dynamics and establishment of a digital workflow by using target tracking with a three-dimensional facial scanner. J Prosthodont Res 2019;63:120-4. Lam WY, Hsung RT, Choi WW, Luk HW, Pow EH. A 2-part facebow for CAD-CAM dentistry. J Prosthet Dent 2016;116:843-7. Jacobs R, Salmon B, Codari M, Hassan B, Bornstein MM. Cone beam computed tomography in implant dentistry: recommendations for clinical use. BMC Oral Health 2018;18:88.
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11. Zhao YJ, Xiong YX, Wang Y. Three-dimensional accuracy of facial scan for facial deformities in clinics: a new evaluation method for facial scanner accuracy. PLoS One 2017;12:e0169402. Corresponding author: Dr Adolfo Di Fiore Department of Neuroscience, Dental School University of Padova, via Giustiniani 2 35100 Padova ITALY Email: adolfo.difi[email protected] Copyright © 2019 by the Editorial Council for The Journal of Prosthetic Dentistry. https://doi.org/10.1016/j.prosdent.2019.05.021
THE JOURNAL OF PROSTHETIC DENTISTRY