Facially generated and additively manufactured baseplate and occlusion rim for treatment planning a complete-arch rehabilitation: A dental technique

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.

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.

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.

Virtual 3-dimensional representation of a completely edentulous patient for computer-aided static implant planning

A technique is described to create a virtual 3-dimensional representation of an edentulous patient by aligning the facial, intraoral, and cone beam computed tomography scans guided by an additively manufactured scan body. Having the virtual patient facilitated the prosthetically driven implant planning, the additive manufacturing of the surgical implant guides, and the interim dental restorations.

Use of an optical jaw-tracking system to record mandibular motion for treatment planning and designing interim and definitive prostheses: A dental technique

Optical jaw-tracking systems can record mandibular motion during the various treatment phases. Also, computer-aided design programs facilitate the integration of a patient's digital information, including recorded mandibular motion, into the design of interim and definitive prostheses. A technique to fabricate a complete mouth implant-supported rehabilitation by using mandibular motion captured with an optical jaw-tracking system is described. The mandibular motion recordings obtained before the treatment are combined with the interim restorations to perform a diagnostic waxing, design the computer-guided implant plan, and fabricate maxillary and mandibular screw-retained implant-supported interim and definitive prostheses. The process allows occlusal adjustments by using the patient's mandibular motion and facilitates the prosthetic design process, minimizing chair time at delivery.

Facial Scanning Accuracy with Stereophotogrammetry and Smartphone Technology in Children: A Systematic Review

The aim of the study was to systematically review and compare the accuracy of smartphone scanners versus stereophotogrammetry technology for facial digitization in children. A systematic literature search strategy of articles published from 1 January 2010 to 30 August 2022 was adopted through a combination of Mesh terms and free text words pooled through boolean operators on the following databases: PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and OpenGrey. Twenty-three articles met the inclusion criteria. Stationary stereophotogrammetry devices showed a mean accuracy that ranged from 0.087 to 0.860 mm, portable stereophotogrammetry scanners from 0.150 to 0.849 mm, and smartphones from 0.460 to 1.400 mm. Regarding the risk of bias assessment, fourteen papers showed an overall low risk, three articles had unclear risk and four articles had high risk. Although smartphones showed less performance on deep and irregular surfaces, all the analyzed devices were sufficiently accurate for clinical application. Internal depth-sensing cameras or external infrared structured-light depth-sensing cameras plugged into smartphones/tablets increased the accuracy. These devices are portable and inexpensive but require greater operator experience and patient compliance for the incremented time of acquisition. Stationary stereophotogrammetry is the gold standard for greater accuracy and shorter acquisition time, avoiding motion artifacts.

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 approaches to facially guided orthodontic and periodontal rehabilitation in the anterior esthetic zone: A case report

OBJECTIVE

The present case report describes digital approaches to plan an orthodontic and periodontal rehabilitation at the anterior esthetic zone.

CLINICAL CONSIDERATIONS

A young patient attended to the dental practice with esthetic concerns. The facially driven digital planning showed the need of an interdisciplinary treatment to improve smile harmony. Orthodontic treatment was conducted with aligners, followed by periodontal and restorative approaches. Tooth alignment was performed with 31 aligners, whereas eight aligners were used for refinement. Harmony between pink and white esthetics was improved with crown lengthening, followed by bleaching.

CONCLUSION

By using a conservative approach, a successful esthetic result was achieved respecting functional and biological principles.

CLINICAL SIGNIFICANCE

Digital resources can be used to the interdisciplinary esthetic planning taking into consideration the harmony between smile and face. This approach allows a predictable outcome of the treatment.

Quantitative evaluation of edentulous maxillomandibular relationship record using diagnostic complete dentures fabricated by CAD and 3D printing

PURPOSE

The present study aimed to quantitatively evaluate the accuracy of the edentulous maxillomandibular relationship record for diagnostic complete dentures fabricated using computer-aided design (CAD) and three-dimensional (3D) printing.

METHODS

Six edentulous patients were enrolled. The maxillomandibular relationship obtained from diagnostic complete dentures (DiaCD test group), that obtained from complete dentures with artificial teeth in the intercuspal position (CD control group), and the centric relationship acquired by gothic arch tracing (CR standard group) were recorded, and 3D surface scanning was performed on these records. Using the CR standard group as a reference, the DiaCD test and CD control group displacements were measured in the horizontal antero-posterior, horizontal right-and-left, and vertical directions. The displacements for the DiaCD test group were compared with those for the CD control group using the Wilcoxon matched-pairs signed rank test.

RESULTS

In terms of centric relationship, the 95% confidence interval of displacement in the horizontal antero-posterior direction was (0.54-1.89) mm in the DiaCD test group and (0.32-1.34) mm in the CD control group. The inter-group difference was significant (P = 0.03).

CONCLUSION

It is feasible to record the edentulous maxillomandibular relationship using diagnostic complete dentures fabricated by CAD/3D printing, but the protrusion of edentulous patients should not be neglected.

3D Virtual Patient Representation for Guiding a Maxillary Overdenture Fabrication: A Dental Technique

This report describes a technique to obtain a 3D virtual representation of a maxillary edentulous patient guided by an additively manufactured intraoral scan body. The intraoral scan body incorporated a custom tray and occlusion rim which facilitated the acquiring of a digital definitive cast, maxillary occlusion rim position, interocclusal registration, and guided the integration of the facial scans. The technique simplified the design and manufacturing of the maxillary overdenture.

Additively manufactured scan body for transferring a virtual 3-dimensional representation to a digital articulator for completely edentulous patients

A technique is described for obtaining a virtual 3-dimensional representation of completely edentulous patients with the virtual definitive casts mounted on the virtual articulator. An additively manufactured intraoral scan body was developed to record the definitive maxillary and mandibular casts and gothic arch interocclusal registration. The intraoral scan body guided the integration of the digital definitive casts and facial scans to obtain the virtual 3-dimensional patient's representation and facilitated the transfer of the definitive casts to the virtual articulator.

Interdisciplinary guided dentistry, digital quality control, and the "copy-paste" concepts

OBJECTIVE

The aim of this report is to present an interdisciplinary approach with novel concepts to virtually plan and achieve esthetics and function.

CLINICAL CONSIDERATIONS

Despite the advancements in the digital workflow applied to restorative dentistry, the final outcomes are commonly not similar to initial planning. To overcome this major limitation, three concepts are proposed: guided dentistry, digital quality control and "copy-paste" dentistry. Guided dentistry consists of simulations in 3D software and also includes the manufacture of guides/appliances to assist dentists in all clinical steps. Digital quality control involves the use of intraoral scanners and 3D software to compare the real outcomes with the pre-operative simulations after every procedure. "Copy-paste" dentistry is a consequence of the previous two concepts. Using the capacity of the software to overlap files, the original project can be maintained and adapted to achieve results more comparable with the initial design. The proposed method associates facially driven treatment planning and periodontal and restorative procedures to perform the patient's dental rehabilitation.

CONCLUSION

Through a guided workflow and digital control of clinical steps, the final outcomes obtained were equivalent and closer to the initial design.

CLINICAL SIGNIFICANCE

In interdisciplinary cases, the treatment plan needs to address individual requirements and to coordinate sequential clinical stages. It is challenging to meet these demands in a conventional process. The proposed concepts engage technological resources to orientate the procedures and to provide assessment in each step. This approach enables the development of a complete and accurate functional-esthetic rehabilitation. Ultimately, the technique presented is reproducible and the results reflect the established plan.

3D printing parameters, supporting structures, slicing, and post-processing procedures of vat-polymerization additive manufacturing technologies: A narrative review

OBJECTIVE

To review the elements of the vat-polymerization workflow, including the 3D printing parameters, support structures, slicing, and post-processing procedures, as well as how these elements affect the characteristics of the manufactured dental devices.

DATA

Collection of published articles related to vat-polymerization technologies including manufacturing workflow description, and printing parameters definition and evaluation of its influence on the mechanical properties of vat-polymerized dental devices was performed.

SOURCES

Three search engines were selected namely Medline/PubMed, EBSCO, and Cochrane. A manual search was also conducted.

STUDY SELECTION

The selection of the optimal printing and supporting parameters, slicing, and post-processing procedures based on dental application is in continuous improvement. As well as their influence on the characteristics of the additively manufactured (AM) devices such as surface roughness, printing accuracy, and mechanical properties of the dental device.

RESULTS

The accuracy and properties of the AM dental devices are influenced by the technology, printer, and material selected. The printing parameters, printing structures, slicing methods, and the post-processing techniques significantly influence on the surface roughness, printing accuracy, and mechanical properties of the manufactured dental device; yet, the optimization of each one may vary depending on the clinical application of the additively manufactured device.

CONCLUSIONS

The printing parameters, supporting structures, slicing, and post-processing procedures have been identified, but additional studies are needed to establish the optimal manufacturing protocol and enhance the properties of the AM polymer dental devices.

CLINICAL SIGNIFICANCE

The understanding of the factors involved in the additive manufacturing workflow leads to a printing success and better outcome of the additively manufactured dental device.

Self-perception and self-representation preference between 2-dimensional and 3-dimensional facial reconstructions among dentists, dental students, and laypersons

STATEMENT OF PROBLEM

Computer-aided design (CAD) software can merge the intraoral digital scan with patient photographs or 3-dimensional (3D) facial reconstructions for treatment planning purposes. However, whether an individual perceives a 3D facial reconstruction as a better self-representation compared with a 2-dimensional (2D) photograph is unclear.

PURPOSE

The purpose of this observational study was to compare self-perception ratings and self-representation preference of the 2D and 3D facial reconstructions among laypersons, dental students, and dentists.

MATERIAL AND METHODS

Three populations participated in the study: laypersons, dental students, and dentists (n=20, N=60). Facial and intraoral features were digitized by using facial and intraoral scanners, and a complete-face smile photograph was obtained. Two simulations were performed for each participant: 2D (2D group) and 3D (3D group) reconstructions. In the 2D group, a maxillary digital veneer waxing from the left to the right second premolars was produced without altering the shape, position, or length of the involved teeth. A software program (Dental Systems; 3Shape A/S) was used to merge the maxillary digital waxing with the full-face smile photograph. One image was obtained for each participant. In the 3D group, a dental software program (Matera 2.4; Exocad GmbH) was used to merge the intraoral and facial scans. Subsequently, 1 video of a 180-degree rotation of each 3D superimposition was obtained. Participants evaluated both superimpositions on a scale from 1 (least esthetically pleasing) to 6 (most esthetically pleasing). Finally, participants were asked which superimposition they preferred for a potential treatment outcome representation.

RESULTS

All the ratings were esthetically pleasing (median group rating 5 or 6). When analyzed solely for differences across occupation groups, ratings for the 2D representation varied significantly across populations (Kruskal-Wallis chi-squared=13.241, df=2, P=.001), but the ratings for the 3D representation did not exhibit statistically significant differences (Kruskal-Wallis chi-squared=4.3756, df=2, P=.112). Ordinal logistic regression revealed no significant main effects but a significant effect of the population×image-type interaction on the esthetic rating. All participants felt well-represented in both the 2D and 3D representations. Also, 40% of dentists, 55% of dental students, and 50% of laypersons preferred the 3D reconstructions. Sex and occupation in general had no effect on the ratings. However, students tended to give higher ratings to the 3D representations of themselves.

CONCLUSIONS

There is no evidence based on the current study that 2D and 3D representations were perceived differently, but representation preferences may depend on a person's occupation. When individuals rated 3D visualization higher than 2D visualization, they strongly preferred the 3D visualization for representing the treatment outcome.

Dental software classification and dento-facial interdisciplinary planning platform

OBJECTIVE

Despite all advantages provided by the digital workflow, its application in clinical practice is still more focused on device manufacturing and clinical execution than on treatment planning and communication. The most challenging phases of treatment, comprehensive planning, diagnosis, risk assessment, and decision-making, are still performed without significant assistance from digital technologies. This article proposes a new dental software classification based on the digital workflow timeline, considering the moment of patient's case acceptance as key in this classification, and presents the ideal software tools for each phase.

CLINICAL CONSIDERATIONS

The proposed classification will help clinicians and dental laboratories to choose the most appropriate software during the treatment planning phase and integrate virtual plans with other software platforms for digitally guided execution. A dento-facial interdisciplinary planning platform virtually simulates interdisciplinary clinical procedures and assists in the decision-making process.

CONCLUSIONS

The suggested classification assists professionals in different phases of the digital workflow and provides guidelines for improvement and development of digital technologies before treatment plan acceptance by the patient.

CLINICAL SIGNIFICANCE

Three-dimensional interdisciplinary simulations allow clinicians to visualize how each dental procedure influences further treatments. With this treatment planning approach, predictability of different procedures in restorative dentistry, orthodontics, implant dentistry, periodontal, and oral maxillofacial surgery is improved.

2D and 3D patient's representation of simulated restorative esthetic outcomes using different computer-aided design software programs

OBJECTIVE

To review the techniques and available 2D and 3D computer-aided design (CAD) software programs to perform a diagnostic waxing for restorative procedures when cone beam computed tomography is not indicated.

OVERVIEW

An electronic review was performed in Medline, Embase, and Scopus search engines. A manual search was also conducted. The articles evaluating methods to obtain a 2D or 3D patient's representation for restorative dental procedures were included. A total of 33 articles were included for full text review. CAD programs provide the capability to integrate facial features from 2D photographs or 3D facial scans and facilitate facially driven digital diagnostic waxing procedures. Diagnostic and design tools varied among the programs, and multiple technique descriptions were found. However, the literature evaluating the accuracy of virtual patients and the perception variations between the 2D and 3D dimensional representations is limited.

CONCLUSIONS

The integration of digital technologies into treatment planning procedures introduce variation into the conventional interfaces; however, the concepts remain the same. Further studies are needed to evaluate the accuracy of the virtual representations and the influence of the type of dimensional representation on the esthetic perceptions among dental professionals.

CLINICAL SIGNIFICANCE

The 2D and 3D CAD software programs facilitate the integration of facial features into digital diagnostic waxing procedures; however, the esthetic perception of the patient's virtual representation might vary among the different systems.

An additively manufactured intraoral scan body for aiding complete-arch intraoral implant digital scans with guided integration of 3D virtual representation

This article describes a polymeric additively manufactured intraoral scan body that facilitates a complete-arch intraoral implant digital scan and guides the superimposition procedures between the facial and digital scans comprising the patient's 3D virtual representation. Furthermore, this novel intraoral scan body can be modified for the patient's specific arch dimensions, enhancing patient comfort and facilitating digitizing.

Designing a complete-arch digital trial tooth arrangement for completely edentulous patients by using an open-source CAD software program: A dental technique

A method for creating a complete-arch digital trial tooth arrangement for completely edentulous patients is described. The technique demonstrates an effective way to reproduce the dental and gingival anatomies by using a free 3D modeling software program. This cost-effective, time-saving, and versatile method allows dental professionals to digitally plan challenging treatments for completely edentulous patients. The technique can also be used to fabricate diagnostic prostheses and implant-supported interim prostheses.

Fully Digital Workflow with Magnetically Connected Guides for Full-Arch Implant Rehabilitation Following Guided Alveolar Ridge Reduction

This technique report describes a fully digital workflow in which two surgical guides (i.e. one for alveolar bone reduction and the other for implant placement) are magnetically connected to ensure stability during full-arch implant surgery following guided bone reduction. Digital prosthesis design as well as virtual bone reduction and implant planning are developed from the superimposition of facial, intraoral and CBCT scans. With this technique, different surgical guides and interim poly(methylmethacrylate) (PMMA) fixed prosthesis are precisely connected with magnets after being digitally designed and 3D-printed. As a result, such magnetic connection allows for satisfactory stability of the implant surgical guide, as well as of the interim fixed PMMA fixed prosthesis during capture of screw-retained abutments.