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The Journal of Prosthetic Dentistry Jan 2024This clinical report describes a digital workflow for the rehabilitation of an 8-year-old patient diagnosed with ectodermal dysplasia. Based on the patient's digital...
This clinical report describes a digital workflow for the rehabilitation of an 8-year-old patient diagnosed with ectodermal dysplasia. Based on the patient's digital primary casts, small custom trays and an arch tracer were designed and 3-dimensionally printed. The mandibular custom tray and retention plate with a tracing screw were assembled with tracing plate, forming an individual assembled mini-arch tracer system to record the jaw relationship together with a conventional facebow and a digital articulator. In addition, composite resin injection guides were designed and fabricated to form the predesigned targeted shape of the abutment teeth and provide a buffer. By following this workflow, complete overdentures with good fit, occlusion, and acceptable esthetics were delivered.
PubMed: 38199946
DOI: 10.1016/j.prosdent.2023.11.036 -
Journal of Dentistry Mar 2024This study aimed to assess the effectiveness of patient-specific motion in restoring anterior guidance and to investigate the influence of occlusal plane position within...
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 (S, S, S, S) 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 S and MDA showed no significant difference between the PSM and NAT groups (p > 0.05). However, S of the ART group was significantly smaller, while MDA was higher than that of the NAT group (p < 0.05). S did not differ significantly (p > 0.05) when the angle of the occlusal plane (AOP) was small. As the AOP increased, S of the ART and AVR groups were significantly smaller than that of the NAT group (p < 0.05). With a large AOP, S 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.
Topics: Humans; Jaw Relation Record; Dental Occlusion; Incisor; Maxilla; Dental Articulators; Computer-Aided Design
PubMed: 38199326
DOI: 10.1016/j.jdent.2024.104833 -
Zhonghua Kou Qiang Yi Xue Za Zhi =... Jan 2024To compare and evaluate the difference in maxillary dentition position using an anatomical facebow and jaw movement analyzer. From March to May 2023, 15 medical...
To compare and evaluate the difference in maxillary dentition position using an anatomical facebow and jaw movement analyzer. From March to May 2023, 15 medical interns from Yantai Stomatological Hospital were recruited, including 9 males and 6 females, aged 20-25 years. Digital models and plaster models of maxillary dentition were obtained from the 15 medical interns. The anatomical facebow group (AFB) and jaw movement analyzer group (JMA) were used to transfer the position of the maxillary dentition to the virtual articulator. The virtual occlusal articulator module of exocad denture design software was used to measure the inclination angle of the occlusal plane of the two groups, the distance between the mesio-incisal angle of the left maxillary central incisor and the lateral center point of the lateral condylar sphere of the virtual occlusal articulator, the distance between the mesial buccal cusp of the maxillary first molar and the lateral center point of the lateral condyle sphere of the virtual articulator. The same marks (mesial incisor point of left maxillary central incisor and mesial buccal cusp point of both maxillary first molars) were measured in two groups of maxillary dentition, and the root-mean-square error between 3 points was calculated. The occlusal plane inclination angle in AFB group (9.11°±3.85°) was significantly larger than that in JMA group (4.94°±2.69°) (=10.45, <0.001). There were significant differences between AFB and JMA groups. The distances from the mesial cusp of the left first molar to the lateral center of the left condylar, from the mesial cusp of the left maxillary central incisor to the lateral center of the left condylar[(91.75±3.05), (129.09±4.60) mm]were significantly smaller than those in the JMA group[(95.68±5.45), (132.41±5.64) mm](=-4.48, =0.001; =-4.21, =0.001). In both groups of models, the distance of the mesial cusp of the left maxillary central incisor was (8.81±2.56) mm, and the distance between mesial buccal cusp of maxillary left first molar was (7.56±2.49) mm, the distance between mesial buccal cusp of maxillary right first molar was (7.13±2.77) mm; the root mean square error was (7.93± 2.94) mm. Compared with 0, the difference was statistically significant (=10.45, <0.001). There were differences between the two methods (anatomical facebow and the jaw movement analyzer) for transferring the maxillary dentition position to the three-dimensional space position of the virtual articulator.
Topics: Male; Female; Humans; Dentition; Dental Occlusion; Incisor; Molar; Dentition, Permanent; Maxilla
PubMed: 38172065
DOI: 10.3760/cma.j.cn112144-20230904-00137 -
Journal of Esthetic and Restorative... May 2024The purpose of this article was to introduce a method for the digital application of three-dimensional (3D) diagnosis and treatment with a virtual articulator and 3D...
OBJECTIVE
The purpose of this article was to introduce a method for the digital application of three-dimensional (3D) diagnosis and treatment with a virtual articulator and 3D data.
CLINICAL CONSIDERATION
With the use of cone-beam computed tomography (CBCT) and intraoral and facial scans, we can create a virtual articulator and evaluate the mandibular position in maximum intercuspation and centric-related occlusion for the patient with an unstable occlusion and temporomandibular disorders (TMD). Based on this, we treated a case using a digital mandibular position indicator (MPI) and fabricated a stabilization splint using a 3D printer. This approach eliminates the traditional impression or model mounting process and the analog face bow transfer. Furthermore, the design of the stabilization splint is accomplished using software.
CONCLUSIONS
The approach outlined in this article offers the potential for a digital diagnosis and treatment process by seamlessly integrating CBCT, intraoral scans, and facial scans with a high degree of accuracy. This may enhance precision in diagnosis and treatment planning, especially for patients with complicated TMD, in addition to facilitating effective communication with orthodontic patients who require thorough attention.
CLINICAL SIGNIFICANCE
Utilizing a virtual articulator and digital MPI for the occlusal evaluation of patients with TMD and unstable occlusion makes it possible to diagnose and analyze the occlusal condition accurately. This approach also allows for precision and efficiency in treatment.
Topics: Humans; Jaw Relation Record; Dental Articulators; Imaging, Three-Dimensional; Models, Dental; Dental Occlusion; Cone-Beam Computed Tomography
PubMed: 38131436
DOI: 10.1111/jerd.13185 -
Scientific Data Dec 2023The use of real-time magnetic resonance imaging (rt-MRI) of speech is increasing in clinical practice and speech science research. Analysis of such images often...
The use of real-time magnetic resonance imaging (rt-MRI) of speech is increasing in clinical practice and speech science research. Analysis of such images often requires segmentation of articulators and the vocal tract, and the community is turning to deep-learning-based methods to perform this segmentation. While there are publicly available rt-MRI datasets of speech, these do not include ground-truth (GT) segmentations, a key requirement for the development of deep-learning-based segmentation methods. To begin to address this barrier, this work presents rt-MRI speech datasets of five healthy adult volunteers with corresponding GT segmentations and velopharyngeal closure patterns. The images were acquired using standard clinical MRI scanners, coils and sequences to facilitate acquisition of similar images in other centres. The datasets include manually created GT segmentations of six anatomical features including the tongue, soft palate and vocal tract. In addition, this work makes code and instructions to implement a current state-of-the-art deep-learning-based method to segment rt-MRI speech datasets publicly available, thus providing the community and others with a starting point for developing such methods.
Topics: Adult; Humans; Dental Articulators; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Speech
PubMed: 38042857
DOI: 10.1038/s41597-023-02766-z -
The Journal of Prosthetic Dentistry Nov 2023The challenges of conventional methods to measure the sagittal condylar inclination and the Bennett angle include patient discomfort and an output of averaged values...
STATEMENT OF PROBLEM
The challenges of conventional methods to measure the sagittal condylar inclination and the Bennett angle include patient discomfort and an output of averaged values calculated on the arc of mandibular movement. Programming these average values into a mechanical or mathematically simulated articulator may introduce occlusal errors.
PURPOSE
The purpose of this clinical study was to compare the sagittal condylar inclination and Bennett angle measurements derived from a conventional electronic tracking device and an optical tracking device.
MATERIAL AND METHODS
Fifteen dentate participants with at least 12 occluding units, 25 years old and above, participated in the study. Each participant's mandibular movements were recorded by the 2 systems for different condylar guidance values. A conventional tracking device, the Cadiax Compact 2, and an optical tracking device, the MODJAW, were used for this study. Sagittal condylar inclination was measured at 3 mm and 5 mm using protrusive records and the values of the Bennett angle at 3 mm were measured using excursive records along the path traced by mandibular condyles. The Wilcoxon signed-rank test was used to analyze the paired data from the 2 methods.
RESULTS
A significant difference was found between right (P=.007) and left sagittal condylar inclinations (P=.010) measured at 3 mm with the conventional and optical tracking devices. A significant difference was found between right (P=.015) and left sagittal condylar inclinations (P=.004) measured at 5 mm with the conventional and optical tracking devices. The right and left Bennett angles measured at 3 mm with the conventional and optical tracking devices were statistically different (P=.043 and P=.035 respectively).
CONCLUSIONS
The sagittal condylar inclination and Bennett angle measured at different positions along the path of movement exhibited significant differences. The sagittal condylar inclination and Bennett angle values obtained from the conventional tracking device were generally significantly less than those derived from the optical tracking device.
PubMed: 38030543
DOI: 10.1016/j.prosdent.2023.10.034 -
Dental Research Journal 2023Horizontal condylar guidance (HCG) is registered by protrusive interocclusal records but in nonarcon articulators, these records can affect the accuracy. The present...
BACKGROUND
Horizontal condylar guidance (HCG) is registered by protrusive interocclusal records but in nonarcon articulators, these records can affect the accuracy. The present study aimed to evaluate the effect of a novel rotation coordinating device (RCD) on condylar guidance setting with protrusive interocclusal records.
MATERIALS AND METHODS
The study was designed as a comparative investigation. Stone maxillary and mandibular casts were mounted on a fully adjustable instrument as the patient. Duplicate casts were mounted on an arcon and a nonarcon articulator with corresponding face bow records and in maximum intercuspation relation. Five different condylar guidance inclinations for both sides (20°, 30°, 40°, 50°, and 60°) were set on the fully adjustable instrument and 16 protrusive interocclusal records were established at each setting. HCG was set for arcon, nonarcon articulators, and nonarcon articulators with RCD. Data were analyzed using one-sample -test to compare with actual HCG and one-way analysis of variance ( =0.05).
RESULTS
Mean HCG for studied articulators was 35.40 for arcon, 30.31 for nonarcon without RCD, and 35.61 for nonarcon with RCD which were significantly different from actual HCG ( < 0.05). HCG of the nonarcon with RCD showed no significant difference with arcon articulator ( = 0.71) while both were significantly different from nonarcon without RCD ( < 0.001).
CONCLUSION
"The RCD" compensates the condylar guidance inclination difference between arcon and nonarcon articulators. The device precisely transfers the hinge movement of the upper member of the articulator to the condylar track.
PubMed: 38020259
DOI: No ID Found -
Bioengineering (Basel, Switzerland) Oct 2023Dental articulation holds crucial and fundamental importance in the design of dental restorations and analysis of prosthetic or orthodontic occlusions. However, common...
Dental articulation holds crucial and fundamental importance in the design of dental restorations and analysis of prosthetic or orthodontic occlusions. However, common traditional and digital articulators are difficult and cumbersome in use to effectively translate the dental cast model to the articulator workspace when using traditional facebows. In this study, we have developed a personalized virtual dental articulator that directly utilizes computed tomography (CT) data to mathematically model the complex jaw movement, providing a more efficient and accurate way of analyzing and designing dental restorations. By utilizing CT data, Frankfurt's horizontal plane was established for the mathematical modeling of virtual articulation, eliminating tedious facebow transfers. After capturing the patients' CT images and tracking their jaw movements prior to dental treatment, the jaw-tracking information was incorporated into the articulation mathematical model. The validation and analysis of the personalized articulation approach were conducted by comparing the jaw movement between simulation data (virtual articulator) and real measurement data. As a result, the proposed virtual articulator achieves two important functions. Firstly, it replaces the traditional facebow transfer process by transferring the digital dental model to the virtual articulator through the anatomical relationship derived from the cranial CT data. Secondly, the jaw movement trajectory provided by optical tracking was incorporated into the mathematical articulation model to create a personalized virtual articulation with a small Fréchet distance of 1.7 mm. This virtual articulator provides a valuable tool that enables dentists to obtain diagnostic information about the temporomandibular joint (TMJ) and configure personalized settings of occlusal analysis for patients.
PubMed: 38002372
DOI: 10.3390/bioengineering10111248 -
Computer Methods and Programs in... Jan 2024The characterization of the vocal tract geometry during speech interests various research topics, including speech production modeling, motor control analysis, and...
BACKGROUND AND OBJECTIVES
The characterization of the vocal tract geometry during speech interests various research topics, including speech production modeling, motor control analysis, and speech therapy design. Real-time MRI is a reliable and non-invasive tool for this purpose. In most cases, it is necessary to know the contours of the individual articulators from the glottis to the lips. Several techniques have been proposed for segmenting vocal tract articulators, but most are limited to specific applications. Moreover, they often do not provide individualized contours for all soft-tissue articulators in a multi-speaker configuration.
METHODS
A Mask R-CNN network was trained to detect and segment the vocal tract articulator contours in two real-time MRI (RT-MRI) datasets with speech recordings of multiple speakers. Two post-processing algorithms were then proposed to convert the network's outputs into geometrical curves. Nine articulators were considered: the two lips, tongue, soft palate, pharynx, arytenoid cartilage, epiglottis, thyroid cartilage, and vocal folds. A leave-one-out cross-validation protocol was used to evaluate inter-speaker generalization. The evaluation metrics were the point-to-closest-point distance and the Jaccard index (for articulators annotated as closed contours).
RESULTS
The proposed method accurately segmented the vocal tract articulators, with an average root mean square point-to-closest-point distance of less than 2.2mm for all the articulators in the leave-one-out cross-validation setting. The minimum P2CP was 0.91mm for the upper lip, and the maximum was 2.18mm for the tongue. The Jaccard indices for the thyroid cartilage and vocal folds were 0.60 and 0.61, respectively. Additionally, the method adapted to a new subject with only ten annotated samples.
CONCLUSIONS
Our research introduced a method for individually segmenting nine non-rigid vocal tract articulators in real-time MRI movies. The software is openly available as an installable package to the speech community. It is designed to develop speech applications and clinical and non-clinical research in fields that require vocal tract geometry, such as speech, singing, and human beatboxing.
Topics: Humans; Dental Articulators; Voice; Speech; Tongue; Magnetic Resonance Imaging; Vocal Cords
PubMed: 37976615
DOI: 10.1016/j.cmpb.2023.107907 -
Journal of Oral Rehabilitation Mar 2024Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known.
OBJECTIVE
To determine the immediate effect of eccentric occlusal interferences on masticatory performance.
METHODS
This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi-adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1-week washout period was applied between tests.
RESULTS
Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p < .05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p < .05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p < .05). The chewing rate did not differ among conditions (p = .1944).
CONCLUSION
Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles.
CLINICAL TRIAL REGISTRATION
Brazilian Registry of Clinical Trials (RBR-8g5zfg8).
Topics: Humans; Dental Occlusion; Mandible; Mastication; Molar; Particle Size; Double-Blind Method
PubMed: 37964439
DOI: 10.1111/joor.13620