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

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 new method to orient a 3-dimensional facial model to natural head position: A preliminary report on accuracy and reproducibility

OBJECTIVES

To establish and validate a novel method to orient a 3-dimensional (3D) facial model to natural head position (NHP) in a stereophotogrammetric system using a 2-dimensional frontal full-face photograph of NHP.

MATERIAL AND METHODS

Specific technique procedure was reported for our method, and in vitro model experiment was performed for accuracy test. A preliminary volunteer study was then planned for reproducibility test.

RESULTS

The accuracy on a 3D-printed test model was within 0.15°. Within an observational cohort of 22 dental students, the angular deviations of different maxillofacial regions (e.g., central forehead, left and right zygomatic regions, apex of nose and mental region) were no more than 2° between the 3D NHP models acquired with a shorter time-interval (1 h from baseline) or a longer time-interval (7 days from baseline), which were all considered clinically insignificant. In addition, the angular deviations were significantly larger with a 7d-interval than with a 1h-interval, indicting a decline in 3D NHP reproducibility over short time duration.

CONCLUSION

The current method may represent a clinically useful protocol for recording and transferring 3D NHP in stereophotogrammetry.

CLINICAL RELEVANCE

It may provide reliable and meaningful reference information for evaluating craniofacial morphology, and be of clinical use in the diagnosis, treatment and follow-ups of patients with aesthetic or deformed craniofacial problems.

Discrepancies of centric occlusion located by using a conventional method and four intraoral scanners combined with a computer-aided design program: A pilot investigation

STATEMENT OF PROBLEM

Intraoral scanners (IOSs) can be used to record the maxillomandibular relationship at centric relation (CR). The articulated digital scans can be imported into a dental computer-aided design (CAD) program and used to locate centric occlusion (CO); however, the accuracy of the CO recorded by using IOSs and a dental CAD program remains unknown.

PURPOSE

The purpose of this clinical study was to compare the position of the CO located by using a conventional method and 4 IOSs combined with a dental CAD program.

MATERIAL AND METHODS

A patient volunteered to participate in this study. Conventional diagnostic stone casts were obtained. A facebow record (Kois Dentofacial Analyzer) was used to transfer the maxillary cast into a semi-adjustable articulator (Panadent PCH Articulator). A Kois deprogrammer (KD) was used to record the maxillomandibular relationship at CR and to transfer the mandibular cast into the articulator. Afterwards, CO was located in the articulated casts by removing the incisal pin and using an 8-µm articulating foil. CO was marked in the casts by using a blue articulating paper (control). Three groups were created based on the IOS used: TRIOS 4, iTero Element 5D Plus, i700, and Primescan. In each IOS group, a maxillary and mandibular scan were obtained. The scans were duplicated 10 times. Afterwards, a bilateral occlusal record captured with the KD was used to articulate each pair of duplicated scans. Each articulated specimen was imported into a CAD program (DentalCAD) and CO was virtually located. The teeth contacting at the CO of each specimen were compared with the control group. Categorical data were analyzed by using the chi-squared test (α=.05).

RESULTS

The chi-squared test revealed a significant association between the IOS system and the location of the CO (P=.004). The highest association was found between the TRIOS 4 and CO position, in which 100% of the specimens obtained the same CO position as in the conventional group. The lowest association was found between the i700 and CO position. In the i700 group, 20% of the specimens showed the same CO position as in the control group. A similar outcome was obtained in the iTero and Primescan groups. In both groups, 60% of the specimens demonstrated the same CO position as the control group.

CONCLUSIONS

The IOS system used to acquire articulated scans at CR impacted the CO position located by using the evaluated digital methods. The TRIOS 4 system was the only IOS that consistently reproduced the same CO position as the conventional method.

Influence of occlusal collision corrections completed by two intraoral scanners or a dental design program on the accuracy of the maxillomandibular relationship

STATEMENT OF PROBLEM

Occlusal collisions of articulated intraoral digital scans can be corrected by intraoral scanners (IOSs) or dental design software programs. However, the influence of these corrections on the accuracy of maxillomandibular relationship is unclear.

PURPOSE

The purpose of this clinical investigation was to measure the effect of occlusal collision corrections completed by the IOSs or dental design software programs on the trueness and precision of maxillomandibular relationship.

MATERIAL AND METHODS

Casts of a participant mounted on an articulator were digitized (T710). The experimental scans were obtained by using 2 IOSs: TRIOS 4 and i700. The intraoral digital scans of the maxillary and mandibular arches were obtained and duplicated 15 times. For each duplicated pair of scans, a bilateral virtual occlusal record was acquired. Articulated specimens were duplicated and assigned into 2 groups: IOS-not corrected and IOS corrected (n=15). In the IOS-not corrected groups, the IOS software program postprocessed the scans maintaining the occlusal collisions, while in the IOS-corrected groups, the IOS software program eliminated the occlusal collisions. All articulated specimens were imported into a computer-aided design (CAD) program (DentalCAD). Three subgroups were developed based on the CAD correction: CAD-no change, trimming, or opening the vertical dimension. Thirty-six interlandmark distances were measured on the reference and each experimental scan to compute discrepancies by using a software program (Geomagic Wrap). Root mean square (RMS) was selected to compute the cast modifications performed in the trimming subgroups. Trueness was examined using 2-way ANOVA and pairwise comparison Tukey tests (α=.05). Precision was evaluated with the Levene test (α=.05).

RESULTS

The IOS (P<.001), the program (P<.001), and their interaction (P<.001) impacted the trueness of the maxillomandibular relationship. The i700 obtained higher trueness than the TRIOS 4 (P<.001). The IOS-not corrected-CAD-no-changes and IOS-not-corrected-trimming subgroups obtained the lowest trueness (P<.001), while the IOS-corrected-CAD-no-changes, IOS-corrected-trimming, and IOS-corrected-opening subgroups showed the highest trueness (P<.001). No significant differences in precision were found (P<.001). Furthermore, significant RMS differences were found (P<.001), with a significant interaction between Group×Subgroup (P<.001). The IOS-not corrected-trimmed subgroups obtained a significantly higher RMS error discrepancy than IOS-corrected-trimmed subgroups (P<.001). The Levene test showed a significant discrepancy in the RMS precision among IOSs across subgroups (P<.001).

CONCLUSIONS

The trueness of the maxillomandibular relationship was influenced by the scanner and program used to correct occlusal collisions. Better trueness was obtained when the occlusal collisions were adjusted by the IOS program compared with the CAD program. Precision was not significantly influenced by the occlusal collision correction method. CAD corrections did not improve the results of the IOS software. Additionally, the trimming option caused volumetric changes on the occlusal surfaces of intraoral scans.

Digital maxillomandibular relationship and mandibular motion recording by using an optical jaw tracking system to acquire a dynamic virtual patient

A technique for digitally recording the maxillomandibular relationship, including the maximum intercuspation and centric occlusion and the patient's mandibular motion, by using an optical jaw tracking system is described. Advantages of this technique include the digital registration of the maxillomandibular relationship and mandibular motion. This technique incorporates the mandibular motion into the 3-dimensional (3D) virtual patient representation to integrate the 3D dynamic virtual patient visualization.

Investigation of the precision of a novel jaw tracking system in recording mandibular movements: A preliminary clinical study

OBJECTIVES

This preliminary study aimed to clinically assess the precision of a novel optical jaw tracking system (JTS) in registering mandibular movements (MMs) of protrusion and mediotrusion.

METHODS

Twenty healthy participants underwent recordings using Cyclops JTS (Itaka Way Med) for functional MMs of protrusion and laterotrusion by two trained clinicians. Each subject performed five registrations at different times according to a standardized pattern within one-month period. The angulations of protrusive and mediotrusive functional paths within the first 2 mm from the maximal intercuspal position (MIP) were calculated for each trace, using a data software for angle measurements. Descriptive statistics were used to assess the repeatability of the recordings for each participant and MM. Additionally, inferential statistics were carried out on standard deviation values obtained (α=0.05).

RESULTS

The overall precision for all the patients was 7.07±3.37° for the protrusion angle, 5.24±2.24° for right laterotrusion and 5.14±3.06° for left laterotrusion angles. The protrusion angle ranged from 3.08° to 13.57°, while the right and left laterotrusion ranged from 1.82° to 9.42° and from 1.58° to 10.59°, respectively. No statistically significant differences were observed between different functional MM types and gender (p > 0.05).

CONCLUSIONS

Recordings functional MMs of mediotrusion and protrusion using Cyclops JTS showed consistent repeatability, regardless of gender and functional MM type. The results revealed non-negligible variations that may be due to the patients' abilities to precisely reproduce jaw movements or to the operator's ability to consistently connect the kinesiograph.

CLINICAL SIGNIFICANCE

Capturing functional MMs digitally and importing the data into dental CAD software is essential for virtual waxing in prosthetic rehabilitations to design a functionalized adapted occlusion. Establishing the repeatability of MM recordings by a JTS is a crucial step in better understanding this novel JTS in the market. This process could facilitate the interpretation of cusp angles, aid in CAD dynamic technical modeling, and enhance clinical data communication between clinicians and technicians in a modern workflow.

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.

Use of an optical jaw tracking system to capture the envelope of function when designing interim and definitive prostheses: A dental technique

Jaw tracking systems can record mandibular motion for incorporation into programs used for designing dental prostheses. However, the protocol for data acquisition and design using the recorded mandibular motion is unclear. The envelope of function recorded in a patient with acceptable occlusal function provides important functional information that can be integrated into the design of dental prostheses. A protocol for recording a patient's digital data, including the envelope of function using a jaw tracker, for incorporation into the design procedures and a delivery protocol are described. This technique may simplify the delivery of prostheses by reducing the adjustments needed to the definitive prostheses.

True horizontal or gravity plane for transferring the maxillary cast into the virtual articulator by using an optical jaw tracking system

Different techniques of transferring the maxillary cast into the analog semi-adjustable articulator by using the true horizontal or gravity reference plane have been reported. However, procedures are required for recording this reference plane and transferring the maxillary cast into the virtual semi-adjustable articulator. In the present manuscript, a technique is described for registering the true horizontal or gravity plane in relationship to the natural head position of the patient by using an optical jaw tracking system. Additionally, the recorded true horizontal plane is used to transfer the maxillary cast into the virtual semi-adjustable articulator by using a dental computer-aided design program. This technique facilitates the maxillary cast transfer into the virtual articulator by using the true horizontal plane recorded with an optical jaw tracking system, maximizing the functionality of the optical jaw tracking device.

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.

Accuracy comparison of the maxillary cast transfer into the virtual semi-adjustable articulator between an analog facebow record and a digital photography technique

STATEMENT OF PROBLEM

Digital photographs can be used for transferring the maxillary cast into the virtual semi-adjustable articulator; however, its accuracy remains unknown.

PURPOSE

The purpose of the present study was to compare the accuracy of the maxillary cast transfer into the virtual semi-adjustable articulator by using an analog and a digital standardized photography technique.

MATERIAL AND METHODS

A maxillary cast was digitized (T710) and positioned into a dental mannequin. The dental midline was not coincident with the facial midline and the maxillary occlusal plane was tilted. A reference scan of the assembled mannequin was obtained by using a facial scanner (Instarisa). Two groups were created based on the technique used to transfer the maxillary cast into the articulator (Panadent PCH): conventional facebow record (CNV group) or digital photograph (Photo group) (n=10). In the CNV group, facebow records (Kois Dentofacial analyzer system) were digitized (T710) and used to transfer the maxillary scan into the articulator by aligning it with the reference platform (Kois adjustable platform). In the Photo group, photographs with a reference glasses (Kois Reference Glasses) positioned into the mannequin were acquired. Each photograph was aligned with the maxillary scan. Then, the maxillary scan was transferred into the articulator by using the true horizontal axis information contained in the photograph. On the reference scan and each specimen, 10 linear measurements between the buccal cusps of the maxillary scan and the horizontal plane of the virtual articulator and a linear measurement between the maxillary dental midline and articulator midline were calculated. The measurements of the reference scan were used as a control to compute trueness and precision. Trueness was analyzed by using 1-way ANOVA followed by the pairwise comparison Tukey test (α=.05). Precision was evaluated by using the Levene and Wilcoxon Rank sum tests (α=.05).

RESULTS

The overall discrepancy measured in the CNV group was 0.620 ±0.396 mm, while in the Photo group it was 1.282 ±0.118 mm. Significant trueness differences were found in the midline (P=.037), anterior (P=.050), posterior right (P<.001), posterior left (P=.012), and overall discrepancy (P<.001) between the CNV and Photo groups. Significant precision discrepancies were found in the midline (P=.012), posterior right (P<.001), anterior (P<.001), posterior left (P=.002), and overall discrepancy (P<.001) between the CNV and Photo groups.

CONCLUSIONS

The facebow record method impacted the accuracy of the maxillary cast transfer. The Photo group obtained better trueness in the midline transfer than the CNV group; however, the CNV group demonstrated better trueness in the anterior, posterior right, posterior left, and overall discrepancy of the maxillary cast transfer compared with the Photo group. Overall, the Photo group obtained better precision than the CNV group.

Is dynamic occlusal design necessary for anterior guidance recovery in the computer-aided design process? An in vitro study

OBJECTIVES

This study aimed to assess the effectiveness of patient-specific motion in restoring anterior guidance and to investigate the influence of occlusal plane position within a virtual articulator on the design of the anterior guide slope for incisors.

METHODS

Twenty participants' intraoral scan, occlusal plane position, and jaw motion data were recorded. The maxillary anterior teeth were virtually prepared, and the crowns were designed based on average virtual articulator (AVR), personalized virtual articulator (ART), and patient-specific motion (PSM). The anterior guide slope of maxillary central incisors (S1, S2, Sc, Sp) and the mesio-distal angle (MDA) of the canine of prostheses were compared to that of natural teeth (NAT). One-Way ANOVA was utilized to evaluate the effectiveness of the three methods in restoring the anterior guidance of maxillary anterior teeth.

RESULTS

The comparison of Sp and MDA showed no significant difference between the PSM and NAT groups (p > 0.05). However, Sp of the ART group was significantly smaller, while MDA was higher than that of the NAT group (p < 0.05). Sp did not differ significantly (p > 0.05) when the angle of the occlusal plane (AOP) was small. As the AOP increased, Sp of the ART and AVR groups were significantly smaller than that of the NAT group (p < 0.05). With a large AOP, Sp of the ART group was notably smaller than that of the NAT group (p < 0.05), while there was no significant difference between the AVR and NAT groups (p > 0.05).

CONCLUSIONS

Occlusal design based on patient-specific motion proved more effective in restoring natural anterior guidance. The anterior guidance of prostheses designed using a virtual articulator was influenced by occlusal plane position.

CLINICAL SIGNIFICANCE

The utilization of a jaw motion tracer facilitated the transfer of personalized occlusal plane positions and recorded jaw motion, which can be integrated into the digital prosthetic workflow for virtual occlusion adjustment. Occlusal design based on patient-specific motion more effectively restored lingual guidance of maxillary anterior crowns.

Digital diagnostic occlusal equilibration combining an intraoral scanner, optical jaw tracking system, and dental design program: A dental technique

Patients with aberrant occlusal patterns, including constricted mastication patterns or occlusal dysfunction, may require occlusal equilibration. Conventional diagnostic procedures involve diagnostic stone casts mounted in the articulator. During diagnostic procedures, occlusal equilibration methods are simulated on mounted stone casts to analyze the amount of dental structure that may need to be removed. A technique to virtually simulate an occlusal equilibration procedure is described. Digital data acquisition procedures include diagnostic casts acquired using an intraoral scanner and the repeatable reference position of the mandible or centric relation, excursive movements, and the mastication pattern captured using an optical jaw tracking system. The jaw tracker and dental design programs are used to simulate the occlusal equilibration.

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.

Discrepancies in the occlusal devices designed by an experienced dental laboratory technician and by 2 artificial intelligence-based automatic programs

STATEMENT OF PROBLEM

Artificial intelligence (AI) models have been developed for different applications, including the automatic design of occlusal devices; however, the design discrepancies of an experienced dental laboratory technician and these AI automatic programs remain unknown.

PURPOSE

The purpose of this in vitro study was to compare the overall, intaglio, and occlusal surface discrepancies of the occlusal device designs completed by an experienced dental laboratory technician and two AI automatic design programs.

MATERIAL AND METHODS

Virtually articulated maxillary and mandibular diagnostic casts were obtained in a standard tessellation language (STL) file format. Three groups were created depending on the operator or program used to design the occlusal devices: an experienced dental laboratory technician (control group) and two AI programs, namely Medit Splints from Medit (Medit group) and Automate from 3Shape A/S (3Shape group) (n=10). To minimize the discrepancies in the parameter designs among the groups tested, the same printing material and design parameters were selected. In the control group, the dental laboratory technician imported the articulated scans into a dental design program (DentalCAD) and designed a maxillary occlusal device. The occlusal device designs were exported in STL format. In the Medit and 3Shape groups, the diagnostic casts were imported into the respective AI programs. The AI programs automatically designed the occlusal device without any further operator intervention. The occlusal device designs were exported in STL format. Among the 10 occlusal designs of the control group, a random design (shuffle deck of cards) was used as a reference file to calculate the overall, intaglio, and occlusal discrepancies in the specimens of the AI groups by using a program (Medit Design). The root mean square (RMS) error was calculated. Kruskal-Wallis, and post hoc Dwass-Steel-Critchlow-Fligner pairwise comparison tests were used to analyze the trueness of the data. The Levene test was used to assess the precision data (α=.05).

RESULTS

Significant overall (P<.001), intaglio (P<.001), and occlusal RMS median value (P<.001) discrepancies were found among the groups. Significant overall RMS median discrepancies were observed between the control and the Medit groups (P<.001) and the control and 3Shape groups (P<.001). Additionally, significant intaglio RMS median discrepancies were found between the control and the Medit groups (P<.001), the Medit and 3Shape groups (P<.001), and the control and 3Shape groups (P=.008). Lastly, significant occlusal RMS median discrepancies were found between the control and the 3Shape groups (P<.001) and the Medit and 3Shape groups (P<.001). The AI-based software programs tested were able to automatically design occlusal devices with less than a 100-µm trueness discrepancy compared with the dental laboratory technician. The Levene test revealed significant overall (P<.001), intaglio (P<.001), and occlusal (P<.001) precision among the groups tested.

CONCLUSIONS

The use of a dental laboratory technique influenced the overall, intaglio, and occlusal trueness of the occlusal device designs obtained. No differences were observed in the precision of occlusal device designs acquired among the groups tested.

Virtual facebow techniques: A scoping review

STATEMENT OF PROBLEM

Although advances in technology continue to improve the acquisition of patient data and the manufacturing of different oral rehabilitations, the method of transferring clinical information to a virtual environment has not yet been consolidated in the literature.

PURPOSE

The purpose of this scoping review was to map the existing literature on different techniques of transferring information from virtual facebows for oral rehabilitation.

MATERIAL AND METHODS

This scoping review was structured using a 5-step methodology based on guidelines proposed by Arksey and O'Malley: (1) characterization of the research question, (2) identification of relevant studies, (3) selection of studies, (4) mapping of results, and (5) selection, summary and reporting of the data. The Joanna Briggs Manual for Evidence Synthesis was followed and the review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). The guiding question for the development of this review was, "What virtual facebow techniques are being used to transfer anatomic data to the virtual environment?"

RESULTS

A total of 1745 articles were found during the search, and 20 were included in this review. Nineteen of the included articles had positive results with the described techniques of registration and transfer of anatomic references to the virtual environment; however, 1 study indicated that the technique was negative.

CONCLUSIONS

Based on the findings, facial scanning, 2-dimensional photographs, and cone beam computed tomography are feasible methods of acquiring extraoral anatomic landmarks. The use of a device that allows the convergence of intraoral and extraoral images by superimposing data was revealed to be a promising option.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Chairside virtual patient protocol. Part 3: In vitro accuracy of a digital facebow

OBJECTIVES

The present study aimed to investigate the trueness and precision of an intraoral transfer element (IOTE) designed for matching intraoral and facial scans.

METHODS

A mannequin head with a maxillary model in position was used. Cone beam computed tomography (CBCT) was used to construct the master model (MM). A digital impression of the maxillary arch was taken using an intraoral scanner, and the IOTE was used to record the maxillary arch position. Twenty facial scans with and twenty without the IOTE in place were performed with a handheld device (Ipad Pro, Apple) using a dedicated software. Digital mounting was performed to build a scan model (SM). Using software for data processing, the three-dimensional deviation between the MM and SM at the central left incisor (#9#), and the left and right first molars (#3#, #14#) was calculated as trueness and linear deviation precision. . Angular deviation was also calculated at the occlusal plane.

RESULTS

The linear deviation trueness at #9#, #3# and #14# was 0.3 ± 0.12 mm, 1.07 ± 0.28 mm, and 0.18 ± 0.34 mm, respectively, whereas the precision was 1.17 ± 0.4 mm, 0.43 ± 0.12 mm, and 0.64 ± 0.28 mm, respectively. Trueness of the angular deviation at the occlusal plane was 2.17 ± 0.46°, whereas the angular deviation precision was 0.64 ± 0.28°.

CONCLUSIONS

Based on in vitro findings the proposed IOTE design is accurate and suitable for clinical use.

CLINICAL SIGNIFICANCE

Direct virtual mounting is a reliable technique in vitro; however, in vivo tests are required.

Maxillary lip dynamics and gingival display revisited: Utilizing standardized metrics

OBJECTIVE

This study was initiated to validate a predictable system for establishing maximum maxillary lip dynamics and highlight the clinical significance of the findings.

MATERIALS AND METHODS

Seventy-five subjects, ranging in age from 25 to 71 years old were photographed with lips in maximum and minimum reveal. The images were digitally analyzed using set references. The statistical analysis was performed using Meta. Numerics version 4.1.4. A Pearson correlation coefficient (r) was carried out to identify relationships between age and maxillary lip dynamics. A p-value less than or equal to 0.05 was considered to be significant.

RESULTS

A greater percentage of participants have posterior gingival display than anterior gingival display. There is greater movement of the maxillary lip at the cuspid than at the central incisor.

CONCLUSION

There was a tendency for lip dynamics to increase at the right central incisor when there is an increase in lip dynamics at the right cuspid. Lip dynamics does not appear to decrease with age.

CLINICAL SIGNIFICANCE

Accurately recording and considering maximum lip dynamics helps avoid asymmetric, excessive or insufficient gingival architecture, insufficient or excessive tooth length and visible restorative margins.

Digital workflows for the management of tooth wear

For patients affected by tooth wear who require treatment to restore their dentition, the methods chosen can increasingly involve digital technology, with potentially less use of traditional, analogue treatment methods. Digital technology has transformed clinical photography and dental radiology, and is now available for most of the stages required for managing these patients. Continuous development of these digital technologies, both in the system capability and in the clinician interface, has brought the digital workflow within reach of more clinicians and therefore, for the treatment of more patients. While it is recognised that the comprehensive use of digital technologies is currently most likely to be used in clinical practice by specialist and private practitioners, it is expected that interest in and understanding of digital workflows will increase throughout the dental profession.This paper provides a step-by-step overview of the digital workflow, for both simple and complex cases.

Four-Dimensional Superimposition Techniques to Compose Dental Dynamic Virtual Patients: A Systematic Review

Four-dimensional virtual patient is a simulation model integrating multiple dynamic data. This study aimed to review the techniques in virtual four-dimensional dental patients. Searches up to November 2022 were performed using the PubMed, Web of Science, and Cochrane Library databases. The studies included were based on the superimposition of two or more digital information types involving at least one dynamic technique. Methodological assessment of the risk of bias was performed according to the Joanna Briggs Institute Critical Appraisal Checklist. Methods, programs, information, registration techniques, applications, outcomes, and limitations of the virtual patients were analyzed. Twenty-seven full texts were reviewed, including 17 case reports, 10 non-randomized controlled experimental studies, 75 patients, and 3 phantoms. Few studies showed a low risk of bias. Dynamic data included real-time jaw motion, simulated jaw position, and dynamic facial information. Three to five types of information were integrated to create virtual patients based on diverse superimposition methods. Thirteen studies showed acceptable dynamic techniques/models/registration accuracy, whereas 14 studies only introduced the feasibility. The superimposition of stomatognathic data from different information collection devices is feasible for creating dynamic virtual patients. Further studies should focus on analyzing the accuracy of four-dimensional virtual patients and developing a comprehensive system.

An Indirect Digital Technique to Transfer 3D Printed Casts to a Mechanical Articulator With Individual Sagittal Condylar Inclination Settings Using CBCT and Intraoral Scans

With the widespread application of digital impression techniques in prosthetic dentistry, accurate intraoral scan mounting, and virtual articulator parameters setting as per patients' anatomic structures are essential for treatment planning and restoration fabrication, especially for complex rehabilitation cases; meanwhile, marginal fit checking, occlusal adjustment, and porcelain layering of restorations are also crucial procedures in all cases in which the analog procedure to mount maxillary arches on a mechanical articulator is still required. This technique article presents an indirect digital approach that can first achieve virtual intraoral scan mounting and sagittal condylar inclination value setting of an Artex virtual articulator based on bony structures provided by a single cone beam computed tomography scan. It then facilitates the transfer of virtually mounted intraoral scans from the virtual articulator to the matched Artex mechanical articulator by relating a digitally scanned mounting plate of the Artex mechanical articulator to the virtual articulator, printing the intraoral scan and mounting plate scan assembly, and then mounting the printed casts on the mechanical articulator based on the printed mounting plate. This technique eliminates the conventional facebow transfer and protrusive bite registration procedures and offers a straightforward approach for the seamless integration of virtual environments and analog workflows into clinical practice. It aids in the design of restorations that are harmonious with the mandibular movements and reduces chairside adjustment time.