-
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 -
Journal of Dentistry Mar 2022The present in vitro study evaluated the reliability and validity of two computerised occlusion analysis systems.
OBJECTIVES
The present in vitro study evaluated the reliability and validity of two computerised occlusion analysis systems.
METHODS
Three occlusion analysis methods were evaluated. The methods included one traditional method (scanning of articulating paper marks (SAP)) and two computerised systems: (dental prescale occlusion analysis system (DPO) and a modified virtual occlusion construction method (VOC)). For reliability evaluation, the occlusion of an articulator-mounted anatomical dentoform was analysed ten times with each of the three methods. Occlusal contact areas and contact number values were obtained and the coefficient of variation (CoV) of each method was compared. For validity evaluation, resin casts of the dentition of 10 human subjects were used for analysis. Paired t-tests, regression analysis and Bland-Altman analysis were used to evaluate the difference and agreement amongst the three methods.
RESULTS
The CoV values of occlusal contact areas from the entire dentition were in the order: SAP (5.7%) < DPO (12.7%) < VOC (15.6%). Higher values was found in the anterior teeth (19.8-40.8%). Significant differences were identified in the occlusal contact areas of the entire dentition and posterior teeth obtained from SAP and DPO; a significant correlation was detected between the two methods (P < 0.01). Bland-Altman agreement analysis indicated good agreement between SAP and VOC.
CONCLUSIONS
Both DPO and VOC have good reliability and validity. They are potential alternatives for analysis of occlusal contacts.
CLINICAL SIGNIFICANCE
The dental prescale occlusion analysis system and the modified virtual occlusion constructed method combine convenience with the objectivity of digital technology. These computerised occlusion analysis systems may be used for quantitative analysis of occlusal contacts in clinical practice, with good reliability and validity.
Topics: Dental Occlusion; Dentition; Humans; Reproducibility of Results
PubMed: 35081421
DOI: 10.1016/j.jdent.2022.104051 -
Maedica Jun 2023The success of complex prosthodontic treatment is believed to be conditioned by condylar path replication in the articulator, as there is a continuing debate in the...
The success of complex prosthodontic treatment is believed to be conditioned by condylar path replication in the articulator, as there is a continuing debate in the scientific community regarding the anatomical relationship between joint and dental morphology. The purpose of this study was to investigate the potential correlation between incisal and condylar guidance. The study population consisted of 20-30-year-old full dentate individuals with Angle class 1 occlusion, whose cone-beam computed tomography (CBCT) scans were analyzed by two investigators. The anterior slope of the right and left glenoid fossa angle and the palatal slope of all maxillary frontal teeth were measured by software tools at three defined landmarks, and the mean values were calculated. Statistical analysis was performed using IBM SPSS Statistics software (version 19.0), and the Pearson r coefficient test was used to assess correlations. The results reveal a highly statistically significant correlation between median condylar slopes and between median incisal slopes of the anterior teeth, on the left and right side, in the three standard areas (p<0.01). However, no significant correlation was found between the condylar slopes and the incisal slopes of the anterior teeth (p>0.01) in class 1 Angle subjects. In conclusion, this study did not provide evidence to support the existence of a significant correlation between incisal and condylar guidance in the population under investigation.
PubMed: 37588818
DOI: 10.26574/maedica.2023.18.2.257 -
Primary Dental Journal Nov 2019An accurate interocclusal record is essential for the successful delivery of fixed prosthodontic restorations. There are various materials and techniques used to obtain...
An accurate interocclusal record is essential for the successful delivery of fixed prosthodontic restorations. There are various materials and techniques used to obtain an interocclusal record in order to facilitate mounting of the dental casts on an articulator. The interocclusal record describes the vertical and horizontal relationship of the maxillary and mandibular teeth. In circumstances where the vertical relationship is not supported through a tripod of widely spaced opposing contacts, the interocclusal record will be needed to restore this vertical support to prevent inaccurate mounting. The clinician should understand when an interocclusal record is required and have an awareness of the different materials and techniques available to record an interocclusal registration.
Topics: Dental Articulators; Dental Care; Dental Occlusion; Dentition; Denture Design; Humans; Jaw Relation Record; Jaw, Edentulous, Partially; Models, Dental; Prosthodontics
PubMed: 31666172
DOI: 10.1308/205016819827601473 -
European Journal of Dental Education :... Aug 2023This study aimed to investigate the difference between senior dental students and prosthodontic faculty members regarding their opinions, attitudes and adoption of six...
INTRODUCTION
This study aimed to investigate the difference between senior dental students and prosthodontic faculty members regarding their opinions, attitudes and adoption of six split-cast techniques for remounting complete dentures. The accuracy of each technique for measurements of the vertical and the anteroposterior dimensions was assessed.
MATERIALS AND METHODS
Six split-cast techniques to remove the casts were compared. A total of 115 participants removed a set of casts on six different articulators, and a questionnaire survey was administered. A digital Vernier caliper was used to measure the linear dimensional changes between the laterally pindexed references on each cast. The data were statistically analysed at α = 0.05.
RESULTS
There were significant differences between senior dental students and prosthodontic faculty members in their responses regarding adoption of daily practice and techniques requiring more skill (p = .001). To adopt a specific technique in daily practice, most students and faculty members chose long round die pins (36.4%) and central groove indexing (CGI; 40.7%), respectively. For techniques requiring more skills, most students and faculty members chose long rectangular die pins (30.7%) and short round dowel pins (33.3%), respectively.
CONCLUSION
Dental students preferred ShRP, whilst faculty members preferred LReP. All participants considered CGI to be the easiest amongst the techniques. For comparison with baseline measurements, both senior dental students and prosthodontic faculty members considered side notch indexing and double dowel pins to be the most accurate techniques for vertical measurements, and CGI for anteroposterior measurements.
Topics: Humans; Dental Articulators; Education, Dental; Prosthodontics; Faculty; Surveys and Questionnaires
PubMed: 35881669
DOI: 10.1111/eje.12841 -
Clinical Oral Investigations Jul 2023This clinical study aimed to compare the performance of various virtual articulator (VA) mounting procedures in the participants' natural head position (NHP).
OBJECTIVES
This clinical study aimed to compare the performance of various virtual articulator (VA) mounting procedures in the participants' natural head position (NHP).
MATERIALS AND METHODS
Fourteen participants with acceptable dentitions and jaw relationships were recruited in this study registered in the Clinical Trials Registry (#NCT05512455; August 2022). A virtual facebow was designed for virtual mounting and hinge axis measurement. Intraoral scans were obtained, and landmarks were placed on each participant's face to register the horizontal plane in NHP. Six virtual mounting procedures were performed for each participant. The average facebow group (AFG) used an indirect digital procedure by using the average facebow record. The average mounting group (AMG) aligned virtual arch models to VA's average occlusal plane. The smartphone facial scan group (SFG) and professional facial scan group (PFG) used facial scan images with Beyron points and horizontal landmarks, respectively. The cone-beam computed tomography (CBCT) scan group (CTG) used the condyle medial pole, and horizontal landmarks were applied. The kinematic facebow group (KFG) served as the control group, and a direct digital procedure was applied using a kinematic digital facebow and the 3D skull model. Deviations of the reference plane and the hinge axis between the KFG and other groups were calculated. The inter-observer variability in virtual mounting software operation was then evaluated using the interclass correlation coefficient (ICC) test.
RESULTS
In virtual condylar center deviations, the CTG had the lowest condylar deviations. The AFG showed larger condylar deviations than PFG, SFG, and CTG. There was no statistically significant difference between the AFG and the AMG and between the PFG and the SFG. In reference plane deviations, the AMG showed the largest angular deviation (8.23 ± 3.29°), and the AFG was 3.89 ± 2.25°. The angular deviations of PFG, SFG, and CTG were very small (means of each group < 1.00°), and there was no significant difference among them. There was no significant difference between the researchers, and the ICC test showed moderate to excellent reliability for the virtual condylar center and good to excellent reliability for the reference plane in the operation of the virtual mounting software.
CONCLUSIONS
CBCT scan provided the lowest hinge axis deviation in virtual mounting compared to average mounting, facebow record, and facial scans. The performance of the smartphone facial scanner in virtual mounting was similar to that of the professional facial scanner. Direct virtual mounting procedures using horizontal landmarks in NHP accurately recorded the horizontal plane.
CLINICAL RELEVANCE
Direct digital procedures can be reliably used for virtual articulator mounting. The use of a smartphone facial scanner provides a suitable and radiation-free option for clinicians.
Topics: Humans; Dental Articulators; Dental Occlusion; Jaw Relation Record; Maxilla; Reproducibility of Results
PubMed: 37247089
DOI: 10.1007/s00784-023-05028-9 -
Folia Medica Mar 2020A variety of indicators to register occlusal contacts are used in the daily dental practice. One of the most frequently used qualitative occlusal indicators is the... (Comparative Study)
Comparative Study
BACKGROUND
A variety of indicators to register occlusal contacts are used in the daily dental practice. One of the most frequently used qualitative occlusal indicators is the articulating paper. Its reliability is often disputed because this indicator could produce false positive results or fail to register any occlusal contacts.
AIM
To compare the number and size of the recorded contacts on a tooth surface obtained with articulating paper and foil.
MATERIALS AND METHODS
Typodonts of upper and lower jaw with intact dental arches Frasaco A-3Z were fixed in a Girbach arcon articulator. Articulating contacts were marked with 12-micron Bausch articulating foil and 200-micron Bausch articulating paper under the same load. For each study a new sheet of the occlusal indicators was used, and 10 repetitions were made for each one. After every marking, the lower jaw was dismounted from the articulator and the distribution of the markings was videographed using a camera. The number of occlusal contacts was entered in a table. We analysed the markings on the first maxillary and first mandibular molars.
RESULTS
We found that fewer and bigger contacts were recorded using the 200-micron articulating paper in comparison with the contacts obtained using the foil.
CONCLUSIONS
The type of occlusal contact indicator has an effect on the number and the size of the occlusal contact markings.
Topics: Dental Occlusion; Humans; Indicators and Reagents; Paper
PubMed: 32337889
DOI: 10.3897/folmed.62.e48018 -
The European Journal of Prosthodontics... Nov 2021Correctly articulated dental casts are essential for certain dental treatment. Articulation can be traditional: using a physical articulator; digital: using a physical...
Correctly articulated dental casts are essential for certain dental treatment. Articulation can be traditional: using a physical articulator; digital: using a physical articulator followed by 3D scanning, or virtual: using 3D scanning and software to articulate scans without initial physical articulation. This study compared the precision of traditional articulation, using physical centric relation records and an articulator and virtually, by digitally aligning scans of the casts and record. Articulated casts and centric relation records were obtained. 12 record pairs were recorded from the articulated casts. Virtual method: all records were scanned, unclamped, in a custom laboratory scanner. The casts were aligned to each scanned record to create virtual articulations. Traditional method: each record was used to physically articulate the casts. Each articulation was recorded using an intraoral scanner. The mean inter-arch separation between three key-points on each cast-pair were used to determine differences in occlusal separation in three anatomical directions, and precision of methods. Traditional articulations: standard deviations in key-point distance never exceeded 0.102mm. The virtual equivalent was 0.059mm. Statistically significant differences (p⟨0.05) between all anteroposterior separation distances were found between the methods, and in three of six lateral/vertical separations. Virtual articulation was significantly more precise than traditional articulation.
Topics: Centric Relation; Dental Articulators; Imaging, Three-Dimensional; Jaw Relation Record; Models, Dental; Workflow
PubMed: 34218536
DOI: 10.1922/EJPRD_2263Osnes07 -
The Journal of Prosthetic Dentistry Dec 2022The use of digital interocclusal registration scans for virtual articulation and mounting has been studied extensively; however, the accuracy of the cross-mounting...
STATEMENT OF PROBLEM
The use of digital interocclusal registration scans for virtual articulation and mounting has been studied extensively; however, the accuracy of the cross-mounting procedures in a digital workflow is not well understood.
PURPOSE
The purpose of this in vitro study was to compare the accuracy of digital and conventional cross-mounting by measuring the 3-dimensional deviation at each step of sequential cross-mounting.
MATERIAL AND METHODS
A set of reference casts and complete-arch interim restorations was prepared for complete-arch complete-coverage restorations, hand-articulated, and mounted in an articulator. The reference casts were then scanned with and without the interim restorations to generate 4 reference casts for cross-mounting. For the conventional group, 15 sets of the 4 casts were printed. Polyvinyl siloxane interocclusal registration records were made of the reference casts for each set, and casts were sequentially cross-mounted. For the digital workflow, 15 sets of bilateral interocclusal registration scans were made of the mounted reference casts and used to align the cast scans. Three-dimensional deviations at 2 anterior and 2 posterior points were recorded between the experimental mountings and the reference casts on each set of casts. Nonpaired t test and analysis of variance (ANOVA) were used to compare the average discrepancy between the 2 groups, and the pooled anterior versus posterior discrepancies were compared (α=.05).
RESULTS
A significant difference was found between conventional and digital cross-mounting procedures (P<.001), but no significant difference was found in either group, conventional (P=.116) or digital (P=.987), at each step of the sequential mountings. The mean ±standard deviation at the final set of related casts in the conventional workflow was 201.6 ±137.0 μm and that in the digital group was 50.3 ±47.5 μm, with a significant difference between anterior and posterior deviations in the digital group (P=.028), but not in the conventional group (P=.143). The mean ±standard deviation anterior conventional deviation was 175.6 ±119.2 μm and that in the digital group was 36.9 ±30.9 μm. The mean ±standard deviation posterior conventional deviation was 227.6 ±50.2 μm and that in the digital group was 63.7 ±57.2 μm.
CONCLUSIONS
Digital cross-mounting was more accurate than conventional cross-mounting, although increased deviation was found in the anterior region compared with the posterior region.
PubMed: 36473749
DOI: 10.1016/j.prosdent.2022.11.001 -
International Journal of Computerized... 2020The Dental Motion Decoder system (DMS-System) is a medical device based on magnetic field technology that records mandible movements. The data can be used to program an...
BACKGROUND
The Dental Motion Decoder system (DMS-System) is a medical device based on magnetic field technology that records mandible movements. The data can be used to program an articulator or can be directly processed over a computer-aided design (CAD) interface. The present study aimed to assess the reproducibility of this system in vitro and in vivo.
MATERIAL AND METHODS
Protrusive and laterotrusive movements were simulated in vitro using an articulator (SAM SE) (Group M) and in vivo (Group P) on one test individual. Measurements were carried out in two ways: 1) Measurements were taken after initializing and referencing the system using the reference points (RPs) once, followed by 30 protrusive and laterotrusive movements (M1 and P1); and 2) Thirty individual measurements were recorded using the RPs before each measurement (M2 and P2). Values for the sagittal condylar path inclination angle (sCPIA) and the Bennett angle (BA) were exported and analyzed. The reproducibility of the system was evaluated using the standard deviations (SDs) of the measurement series (sCPIA and BA for M1, M2, P1, and P2).
RESULTS
In vitro tests M1 (SD: sCPIA = 0.08 degrees; BA = 0.06 degrees) and M2 (SD: sCPIA = 0.26 degrees; BA = 0.11 degrees) showed significantly higher reproducibility (P < 0.001) compared with the in vivo measurements P1 (SD: sCPIA = 0.61 degrees; BA = 0.45 degrees) and P2 (SD: sCPIA = 1.4 degrees; BA = 0.65 degrees).
CONCLUSION
Within the limitations of the present study, the deviation in vitro, representing the reproducibility of the DMD-System, is smaller than the biologic variance observed in vivo. Therefore, reliable measurements under clinical conditions can be assumed.
Topics: Dental Articulators; Humans; Jaw Relation Record; Magnets; Mandibular Condyle; Movement; Reproducibility of Results
PubMed: 32207460
DOI: No ID Found