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The Journal of Prosthetic Dentistry Jun 2024When using conventional methods, centric occlusion (CO) can be determined on conventional gypsum casts that are mounted in an analog articulator at centric relation...
When using conventional methods, centric occlusion (CO) can be determined on conventional gypsum casts that are mounted in an analog articulator at centric relation (CR). In the digital environment, intraoral scanners (IOSs) can be used to record maxillary and mandibular scans articulated in CR. However, a digital protocol to locate the CO on articulated intraoral digital scans at CR by using computer-aided design (CAD) programs is needed. The present manuscript describes a straightforward technique to record CR by combining an IOS and a Kois deprogrammer. Afterwards, the acquired digital data are imported into a CAD program to locate CO. The technique includes a complete digital protocol to locate CO by using 3 different CAD programs: open-access non-dental, open-access dental, and dental CAD program.
PubMed: 38834391
DOI: 10.1016/j.prosdent.2024.05.002 -
Journal of Esthetic and Restorative... May 2024The purposes of this study were to classify the described digital facebow techniques for transferring the maxillary cast into the semi-adjustable virtual articulator... (Review)
Review
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.
PubMed: 38778662
DOI: 10.1111/jerd.13264 -
Oral Diseases May 2024This study aims to evaluate food impaction on three-dimensional (3D) printed models with periodontal ligament simulation.
OBJECTIVE
This study aims to evaluate food impaction on three-dimensional (3D) printed models with periodontal ligament simulation.
MATERIALS AND METHODS
Based on a commercial typodont pair, 3D maxillary and mandibular models were created with no teeth and with tooth sockets that were 1 mm wider than the original ones from 24 to 27 or 34 to 37 for periodontal ligament simulation with vinyl polysiloxane impression material. In total, 35 pairs of 7 combinations, including maxillary/mandibular typodonts in occlusion with maxillary/mandibular 3D models with/without a distal gap of canines on 3D models (tooth 23 or 33) were mounted on hinge articulators and divided into seven groups (n = 5). Each sample experienced the same manual chewing simulation on a customized device. The proximal surfaces were photographed to measure the percentage of food impaction area using ImageJ software.
RESULTS
Group with fixed maxillary and mandibular teeth showed more food impaction than other groups with significant differences in the average of maxilla and the average of all proximal areas.
CONCLUSION
The flexibility of the periodontal ligament and the degree of freedom of the teeth in their sockets may contribute to the extent of food impaction in proximal spaces.
PubMed: 38735836
DOI: 10.1111/odi.14989 -
The Journal of Prosthetic Dentistry May 2024Different techniques of transferring the maxillary cast into the analog semi-adjustable articulator by using the true horizontal or gravity reference plane have been...
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.
PubMed: 38714458
DOI: 10.1016/j.prosdent.2024.03.049 -
The Journal of Prosthetic Dentistry Apr 2024Different digital methods have been described for transferring the maxillary cast into a virtual articulator; however, its accuracy remains uncertain.
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.
PubMed: 38641478
DOI: 10.1016/j.prosdent.2024.03.011 -
The Journal of Prosthetic Dentistry Apr 2024Digital photographs can be used for transferring the maxillary cast into the virtual semi-adjustable articulator; however, its accuracy remains unknown.
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.
PubMed: 38609764
DOI: 10.1016/j.prosdent.2024.03.003 -
The Journal of Prosthetic Dentistry Apr 2024Maxillary and mandibular scans can be articulated in maximum intercuspal position (MIP) by using an artificial intelligence (AI) based program; however, the accuracy of...
STATEMENT OF PROBLEM
Maxillary and mandibular scans can be articulated in maximum intercuspal position (MIP) by using an artificial intelligence (AI) based program; however, the accuracy of the AI-based program locating the MIP relationship is unknown.
PURPOSE
The purpose of the present clinical study was to assess the accuracy of the MIP relationship located by using 4 intraoral scanners (IOSs) and an AI-based program.
MATERIAL AND METHODS
Conventional casts of a participant mounted on an articulator in MIP were digitized (T710). Four groups were created based on the IOS used to record a maxillary and mandibular scan of the participant: TRIOS4, iTero, i700, and PrimeScan. Each pair of nonarticulated scans were duplicated 20 times. Three subgroups were created: IOS, AI-articulated, and AI-IOS-corrected subgroups (n=10). In the IOS-subgroup, 10 duplicated scans were articulated in MIP by using a bilateral occlusal record. In the AI-articulated subgroup, the remaining 10 duplicated scans were articulated in MIP by using an AI-based program (BiteFinder). In the AI-IOS-corrected subgroup, the same AI-based program was used to correct the occlusal collisions of the articulated specimens obtained in the IOS-subgroup. A reverse engineering program (Geomagic Wrap) was used to calculate 36 interlandmark measurements on the digitized articulated casts (control) and each articulated specimen. Two-way ANOVA and pairwise multiple comparison Tukey tests were used to analyze trueness (α=.05). The Levene and pairwise multiple comparison Wilcoxon rank tests were used to analyze precision (α=.05).
RESULTS
Significant trueness discrepancies among the groups (P<.001) and subgroups (P<.001) were found, with a significant interaction group×subgroup (P<.001). The Levene test showed significant precision discrepancies among the groups (P<.001) and subgroups (P=.005). The TRIOS4 and iTero groups obtained better trueness and lower precision than the i700 and PrimeScan systems. Additionally, the AI-articulated subgroup showed worse trueness and precision than the IOS and AI-IOS-corrected subgroups. The AI-based program improved the MIP trueness of the scans articulated by using the iTero and PrimeScan systems but reduced the MIP trueness of the articulated scans obtained by using the TRIOS4 and i700.
CONCLUSIONS
The trueness and precision of the maxillomandibular relationship was impacted by the IOS system and program used to locate the MIP.
PubMed: 38604907
DOI: 10.1016/j.prosdent.2024.03.007 -
The Journal of Prosthetic Dentistry Apr 2024With the development of digital dental technologies, a complete digital workflow without using physical casts has become possible. However, for certain clinical and...
With the development of digital dental technologies, a complete digital workflow without using physical casts has become possible. However, for certain clinical and dental laboratory procedures, especially in complex rehabilitation treatments, physically mounted casts in an ideal location in a mechanical articulator are still necessary for treatment planning and restoration fabrication. This technique report describes a digital approach to fabricating a custom transfer plate to cross mount intraoral scan casts from a virtual articulator to the corresponding mechanical articulator. This technique eliminates the need for conventional physical facebow transfer processes and offers a straightforward approach to integrating virtual procedures with analog workflows.
PubMed: 38604906
DOI: 10.1016/j.prosdent.2024.03.012 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Apr 2024This clinical study aimed to assess the trueness of three intraoral scanners for the recor-ding of the maximal intercuspal position (MIP) to provide a reference for...
OBJECTIVES
This clinical study aimed to assess the trueness of three intraoral scanners for the recor-ding of the maximal intercuspal position (MIP) to provide a reference for clinical practice.
METHODS
Ten participants with good occlusal relationship and healthy temporomandibular joint were recruited. For the control group, facebow transferring procedures were performed, and bite registrations at the MIP were used to transfer maxillary and mandibular casts to a mechanical articulator, which were then scanned with a laboratory scanner to obtain digital cast data. For the experimental groups, three intraoral scanners (Trios 3, Carestream 3600, and Aoralscan 3) were used to obtain digital casts of the participants at the MIP following the scanning workflows endorsed by the corresponding manufacturers. Subsequently, measurement points were marked on the control group's digital casts at the central incisors, canines, and first molars, and corresponding distances between these points on the maxillary and mandibular casts were measured to calculate the sum of measured distances (D). Distances between measurement points in the incisor (D), canine (D), and first molar (D) regions were also calculated. The control group's maxillary and mandibular digital casts with the added measurement points were aligned with the experimental group's casts, and D, D, D, and D values of the aligned control casts were determined. Statistical analysis was performed on D, D, D, and D obtained from both the control and experimental groups to evaluate the trueness of the three intraoral scanners for the recording of MIP.
RESULTS
In the control group, D, D, D, and D values were (39.58±6.40), (13.64±3.58), (14.91±2.85), and (11.03±1.56) mm. The Trios 3 group had values of (38.99±6.60), (13.42±3.66), (14.55±2.87), and (11.03±1.69) mm. The Carestream 3600 group showed values of (38.57±6.36), (13.56±3.68), (14.45±2.85), and (10.55±1.41) mm, while the Aoralscan 3 group had values of (38.16±5.69), (13.03±3.54), (14.23±2.59), and (10.90±1.54) mm. Analysis of variance revealed no statistically significant differences between the experimental and control groups for overall deviation D (=0.96), as well as local deviations D (=0.98), D (=0.96), and D (=0.89).
CONCLUSIONS
With standardized scanning protocols, the three intraoral scanners demonstrated comparable trueness to traditional methods in recording MIP, fulfilling clinical requirements.
Topics: Humans; Molar; Incisor; Mandible; Maxilla; Computer-Aided Design; Imaging, Three-Dimensional; Dental Impression Technique
PubMed: 38597082
DOI: 10.7518/hxkq.2024.2023277 -
Journal of Pharmacy & Bioallied Sciences Feb 2024The transfer of interocclusal data from the patient's mouth to articulators utilizing various types of recording media is necessary for the production of dental...
UNLABELLED
The transfer of interocclusal data from the patient's mouth to articulators utilizing various types of recording media is necessary for the production of dental prostheses. Occlusal errors in the final prosthesis result from any discrepancies in these interocclusal records.
MATERIALS AND METHODS
The purpose of this study was to assess the linear dimensional changes in the four elastomeric interocclusal recording materials as well as the material's resistance to compression during the cast mounting on the articulator.
RESULT
All four elastomeric materials showed decreasing stability over time and 2 mm thickness showed the highest compression resistance with minimal articulation error.
CONCLUSION
Dimensional stability depends on material and time factors, and compressive resistance decreases with increasing thickness.
PubMed: 38595621
DOI: 10.4103/jpbs.jpbs_1047_23