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The Journal of Advanced Prosthodontics Feb 2023To compare the sagittal condylar inclination (SCI) in dentate individuals measured by the different methods with mechanical articulator (MA), virtual articulator (VA),...
PURPOSE
To compare the sagittal condylar inclination (SCI) in dentate individuals measured by the different methods with mechanical articulator (MA), virtual articulator (VA), and a jaw tracking device (JTD) system.
MATERIALS AND METHODS
A total of 22 healthy dentate participants were enrolled in this study. For MA workflow, the SCI was obtained by a semi-adjustable articulator with protrusive interocclusal records. The SCI was also set on a VA by aligning intraoral scan (IOS) with cone beam computed tomography (CBCT) and facial scan (FS), respectively. These virtual workflows were conducted in a dental design software, namely VA and VA. Meanwhile, a JTD system was also utilized to perform the measurement. Intraclass correlation was used to assess the repeatability within workflows. The bilateral SCI values were compared by Wilcoxon matched-pairs signed rank test for each workflow, and Kruskal-Wallis test and post hoc p-value Bonferroni correction were used to compare the differences among four workflows. The agreement of VA, VA, and JTD compared with MA was evaluated by Bland-Altman analysis.
RESULTS
Intraclass correlation of the SCI revealed a high degree of repeatability for each workflow. There were no significant differences between the left and right sides ( > .05), except for VA ( = .028). Significant differences were not found between MA and VA ( > .05). Bland-Altman plots indicated VA, VA, and JTD were considered to substitute MA with high 95% limits of agreement.
CONCLUSION
The workflow of VA provided an alternative approach to measure the SCI compared with MA.
PubMed: 36908753
DOI: 10.4047/jap.2023.15.1.11 -
Journal of Prosthodontics : Official... Jan 2022To investigate the trueness and precision of virtual facebow records using a smartphone as a three-dimensional (3D) face scanner.
PURPOSE
To investigate the trueness and precision of virtual facebow records using a smartphone as a three-dimensional (3D) face scanner.
MATERIAL AND METHODS
Twenty repeated virtual facebow records were performed on two subjects using a smartphone as a 3D face scanner. For each subject, a virtual facebow was attached to his/her maxillary arch, and face scans were performed using a smartphone with a 3D scan application. The subject's maxillary arch intraoral scan was aligned to the face scan by the virtual facebow fork. This procedure was repeated 10 times for each subject. To investigate if the maxillary scan is located at the right position to the face, these virtual facebow records were superimposed to a cone-beam computed tomography (CBCT) head scan from the same subject by matching the face scan to the 3D face reconstruction from CBCT images. The location of maxillary arch in virtual facebow records was compared with its position in CBCT. The "trueness" of the proposed procedure is defined as the deviation between maxilla arch position in virtual facebow records and the CBCT images. The "precision" is defined as the deviation between each virtual facebow record. The linear deviation at left central incisor (#9), left first molar (#14), and right first molar (#3), as well as angular deviation of occlusal plane were analyzed with descriptive statistics. Differences between two objects were also explored with Mann Whitney U test.
RESULTS
The 20 virtual facebow records using the smartphone 3D scanner deviated from the CBCT measurements (trueness) by 1.14 ± 0.40 mm at #9, 1.20 ± 0.50 mm at #14, 1.12 ± 0.51 mm at the #3, and 1.48 ± 0.56° in the occlusal plane. The VFTs deviated from each other by 1.06 ± 0.50 mm at #9, 1.09 ± 0.49 mm at #14, 1.11 ± 0.58 mm at #3, and 0.81 ± 0.58° in the occlusal plane. When all sites combined, the trueness was 1.14 ± 0.40 mm, and the precision was 1.08 ± 0.52 mm. Out of eight measurements, three measurements were significantly different between subjects. Nevertheless, the mean difference was small.
CONCLUSIONS
Virtual facebow records made using smartphone-based face scan can capture the maxilla position with high trueness and precision. The deviation can be anticipated as around 1 mm in linear distance and 1° in angulation.
Topics: Computer-Aided Design; Cone-Beam Computed Tomography; Dental Occlusion; Female; Humans; Imaging, Three-Dimensional; Male; Maxilla; Models, Dental; Smartphone
PubMed: 33876857
DOI: 10.1111/jopr.13366 -
The Journal of Prosthetic Dentistry Feb 2020Complex digital workflows have been developed to create virtual dental patients. Direct and indirect digital methods are available for transferring analog patient...
STATEMENT OF PROBLEM
Complex digital workflows have been developed to create virtual dental patients. Direct and indirect digital methods are available for transferring analog patient information to virtual articulators. The direct method consists solely of digital workflows. The indirect method combines analog steps and digital procedures, representing an intermediate solution between the analog and direct digital approach. Studies that have investigated the overall accuracy of the virtual working space are sparse.
PURPOSE
The purpose of this clinical study was to investigate the accuracy of the virtual dental space using the indirect digital workflow.
MATERIAL AND METHODS
Mounted gypsum casts of 18 patients were used for indirect scanning. The maxillary casts were mounted in their skull-related position with a kinematic facebow. The mandibular casts were mounted in centric relation to the maxillary casts. The obtained digitized casts were transferred to a virtual articulator. An occlusal analysis was performed both in the analog and virtual environments, and the coordinates of matching analog and virtual contact points were measured. The trueness and precision of the indirect transferring procedure were assessed.
RESULTS
A total of 194 analog points was considered in the reference. Ninety-three percent of all analog points matched a virtual correspondent, and 96% of the analog first contacts between the casts were also present as first contacts in the virtual space. The trueness of the data transfer, corresponding to the spatial distance between the matching analog and virtual points, was 0.55 ±0.31 mm. The maximum recorded deviation was 1.02 mm.
CONCLUSIONS
The correspondence between the number and position of analog and virtual contacts was high. The mean absolute deviation of the matching point-pairs was better than that reported for the direct digital method. Under the conditions described, the virtual dental space created with the indirect digital method can be reliably used for virtual occlusal analysis in clinical practice.
Topics: Dental Articulators; Humans; Jaw Relation Record; Mandible; Maxilla; Models, Dental
PubMed: 31227241
DOI: 10.1016/j.prosdent.2018.12.019 -
Journal of International Society of... 2021To meet the needs of society, it is obligatory to provide standardized skill training to undergraduate students in dental colleges. Surveys related to teaching...
OBJECTIVES
To meet the needs of society, it is obligatory to provide standardized skill training to undergraduate students in dental colleges. Surveys related to teaching curriculum are valuable means to evaluate education across the country. The aim of this study was to find the trends in the undergraduate teaching curriculum, by determining the differences in the teaching methods and principles of fabrication of removable partial dentures in dental colleges in Saudi Arabia and to compare these with the curriculum of North American dental schools and Turkish dental schools.
MATERIALS AND METHODS
An online survey was conducted in 23 dental colleges of Saudi Arabia. Descriptive data analysis was performed to synopsize the information.
RESULTS
Eighteen out of 23 (78.23%) dental colleges of Saudi Arabia answered the questionnaire; 88.9% of the colleges follow the practice of using custom trays for making final impressions; and 44.4% of the colleges use only polyvinyl siloxane for making final impressions. Semiadjustable articulators were commonly used for mounting study casts (61.1%) and master casts (66.6%). An in-house production laboratory is present in 72.2% of the colleges. Cobalt-chromium alloy is used in 94.4% of the colleges for the framework. A set protocol for postinsertion adjustment visits is followed in 94.4% of the colleges.
CONCLUSIONS
Dental colleges of Saudi Arabia have similar standards of removable partial denture education at the undergraduate level, with variations in a few aspects. Removable partial denture teaching programs of Saudi Arabian dental colleges are comparable to similar programs in dental schools of the United States and Turkey.
PubMed: 34036075
DOI: 10.4103/jispcd.JISPCD_374_20 -
Stomatologiia 2022Was determination of TMJ anatomical and functional parameters in patients without clinical manifestations of TMJ dysfunction and analysis of possible relationships...
THE AIM OF THE STUDY
Was determination of TMJ anatomical and functional parameters in patients without clinical manifestations of TMJ dysfunction and analysis of possible relationships between them.
MATERIAL AND METHODS
TMJ anatomical parameters of 25 volunteers (22-27 years old) without TMJ dysfunction, malocclusion and more than one tooth adentia were determined on CT scans and lab teeth scans: inclination of the distal slopes of the articular eminence (DS AE), height and width of the condyles, height of AE, inclination of the longitudinal axes of the condyles; as well as functional parameters of LJ movements: horizontal condylar inclination (HCI) during protrusion and laterotrusion, lateral condylar inclination during protrusion and laterotrusion, immediate side shift, incisor and canine guidance, and correlations between them were evaluated.
RESULTS
The majority of the TMJ anatomical parameters are almost equal by mean values on the right and left sides. The main TMJ functional parameters on the right and left sides also have similar values but much higher variability, asymmetry and unpredictability. The existing anatomical asymmetry of the DS AE is compensated by articular discs, which makes HCI more symmetrical.
CONCLUSION
Protrusion movements have a higher probability of reproduction by mechanical articulators while laterotrusion movements have a very low probability. The existence of relationship between the inclination of DS AE and HCI, between HCI and the incisor guidance, between the inclination of DS AE and the incisor guidance is questionable. The conducted research proves the weakness or complete absence of correlation between them.
Topics: Dental Occlusion; Humans; Incisor; Mandibular Condyle; Temporomandibular Joint; Temporomandibular Joint Dysfunction Syndrome
PubMed: 35640180
DOI: 10.17116/stomat202210103149 -
Journal of Oral Biology and... 2022Gothic arch Tracing has been a common modality in the recording of centric jaw relation. There has been two ways of recording the gothic tracing. They are extra oral and...
INTRODUCTION
Gothic arch Tracing has been a common modality in the recording of centric jaw relation. There has been two ways of recording the gothic tracing. They are extra oral and intra oral tracing. Among the extra oral tracers hight tracers are the most used tracers.
AIM
Intra-oral and extra-oral tracers have a number of individual advantages and limitations. With the idea to overcome the short comings of both the tracers, hybrid tracers were made. Hybrid tracers could be a good alternative to the Hight-tracer in recording centric relation and can provide better clinical and teaching experience to the students.
METHODOLOGY
The hybrid tracer is a two-component assembly, upper and lower component. The upper component has a central bearing plate and stylus in continuation with the central bearing plate. The lower component has central bearing device with three central bearing points one anteriorly and two posteriorly, and it has a tracing platform (15 × 35 mm) in continuation with the central bearing device. The length of these upper and lower components ismade to confine within the incisal rod of semi adjustable articulator.
RESULT
hybrid tracers showed more accuracy while recording the centric jaw relation. There was more stability and equalization of pressure during the movement due to a tripod effect of three screws. Hence it provided more precise recording and being less technique sensitive. It was also more comfortable and acceptable by the patient.
CONCLUSION
hybrid tracers hence will provide more accuracy and precision in recording of horizontal jaw relation. This will in turn help in fabricating a successful prosthesis and enhance the well-being of the patient. This tracer will also be significant in institutions for educational purpose.
CLINICAL IMPLICATION
Hybrid tracers are simple, non-technique sensitive, provide balance, equalization of pressure, stabilize the occlusal rims well, are close to the centre of rotation providing precise record and provide easy access and visibility to the operator which will help the operator in guiding the patient well for a correct jaw relation.
PubMed: 36203859
DOI: 10.1016/j.jobcr.2022.09.013 -
The Journal of Prosthetic Dentistry Jun 2021The purpose of this technique report was to describe a fully digital technique to evaluate the mandibular position both in centric relation occlusion (CRO) and maximal...
The purpose of this technique report was to describe a fully digital technique to evaluate the mandibular position both in centric relation occlusion (CRO) and maximal intercuspation position (MIP). The procedure transfers data relative to the position of the maxillary and mandibular dentition to a virtual articulator based on a single cone beam computed tomography (CBCT) image. A CBCT scan of the patient was obtained in CRO, and the maxillary and mandibular casts were scanned both in CRO and MIP with an intraoral scanner. The model CRO scan data were registered on the dental part of the CBCT image by using a virtual articulator program, and a virtual facebow transfer process and mounting was performed. The virtual articulator was positioned in the right and left condyle medial pole and right orbitale. The mandibular position was evaluated in CRO and MIP by superimposing the data of the mandible position in both CRO and MIP. A quantitative 3D measurement was obtained by using the grid function. Based on this protocol, it is possible to use a fully digital approach to transfer the position of a patient's maxillary dentition to a virtual articulator based on the data from a single CBCT scan and intraoral scans. This technique eliminates the traditional facebow transfer and mounting process and complicated laboratory procedures for evaluating mandibular positional changes in CRO and MIP.
Topics: Cone-Beam Computed Tomography; Dental Articulators; Dental Occlusion; Humans; Jaw Relation Record; Mandible; Models, Dental
PubMed: 32624222
DOI: 10.1016/j.prosdent.2020.04.002 -
Medicina (Kaunas, Lithuania) Jul 2023Learning to speak properly requires a fully formed brain, good eyesight, and a functioning auditory system. Defective phonation is the outcome of a failure in the... (Review)
Review
Learning to speak properly requires a fully formed brain, good eyesight, and a functioning auditory system. Defective phonation is the outcome of a failure in the development of any of the systems or components involved in speech production. Dentures with strong phonetic skills can be fabricated with the help of a dentist who has a firm grasp of speech production and phonetic characteristics. Every dentist strives to perfect their craft by perfecting the balance between the technical, cosmetic, and acoustic aspects of dentistry, or "phonetics". The ideal prosthesis for a patient is one that not only sounds good but also functions well mechanically and aesthetically. Words are spoken by using articulators that alter their size and form. : Therefore, a prosthesis should be made in such a way that it does not interfere with the ability to communicate. As a result, a prosthodontist has to have a solid grasp of how speech is made and the numerous parts that go into it.
Topics: Humans; Speech; Phonetics; Phonation; Learning; Brain
PubMed: 37512133
DOI: 10.3390/medicina59071322 -
Journal of Prosthodontics : Official... Mar 2022Although the evolution of digital technology continues to improve patient data acquisition, the ability to both standardize the recording of the maxillary occlusal plane...
Although the evolution of digital technology continues to improve patient data acquisition, the ability to both standardize the recording of the maxillary occlusal plane and capture the necessary dynamic data for dento-facial analysis remains elusive. This article describes step-by-step techniques to position the maxilla on an articulator using the natural head position and a facial reference system (Kois Facial Reference Glasses) for both analog and digital workflows. A photographic technique will be presented that captures the natural head position and allows the clinician to align a 2D reference photograph with the maxillary intraoral digital scan and the virtual articulator. Using this reference photograph, the clinician can record and communicate to the technician the maxillary arch position in relationship with the facial references, as well as transfer the additively manufactured casts in the same facial orientation for mounting and analysis either virtually or on an analog articulator.
Topics: Dental Articulators; Dental Occlusion; Face; Humans; Jaw Relation Record; Maxilla; Models, Dental
PubMed: 34605582
DOI: 10.1111/jopr.13437 -
Journal of Biological Regulators and... 2021The aim of this article is to describe how, during the provisional and definitive prosthetic phases, using new digital technologies, it is possible to improve the...
The aim of this article is to describe how, during the provisional and definitive prosthetic phases, using new digital technologies, it is possible to improve the ergonomics of the prosthetist's work and reduce the discomfort of patients, subjecting them to the fewest possible appointments at the dentist. The proposal of a full digital protocol, described by the following case report, for the realization of a definitive prosthetic rehabilitation supported by a reduced number of implants, in fact, allows to considerably reduce the number of appointments and reduce any bias. A 67-year-old male patient presents for the first visit to the Department of Dentistry of the San Raffaele Hospital, wearing a removable upper prosthesis and with the request to heal the aesthetic and functional situation through prosthetics fixed. An initial panoramic radiograph was performed, intra and extra oral photos were taken and also intraoral impressions. A stereo-lithographic models are obtained from intraoral scans, and two total prostheses, upper and lower, were packaged for the provisional post-surgical phase was performed. In accordance with the All-on-4 method 8 implant fixtures were placed. For the final prosthetic phase, the patient underwent only two operative sessions. In the first session, scans were taken with the provisionals in situ, of the patient's mucous membranes and with the Scan-abutments in place. In the second session using specific CADSoftware the matching of the STL files of the three scans were created, the opposing arches of the patient were related on a digital articulator, and the milled titanium bars were immediately constructed and finished with the resin. Finally, the definitive prostheses were delivered to the patient without any other test. Digital technology has allowed a clear reduction in working times and costs and has allowed the reduction of stress for patients who undergo invasive and extensive treatments to recover aesthetics and function, and for clinicians who must manage complex cases with fewer appointments possible.
Topics: Aged; Humans; Male; Prostheses and Implants; Prosthesis Implantation; Titanium; Workflow
PubMed: 34425664
DOI: 10.23812/21-4supp1-8