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Medical Science Monitor : International... Nov 2023BACKGROUND The aim of this study was to assess and compare the vertical/horizontal dimensions and occlusal accuracy of non-working/opposing casts obtained from three...
BACKGROUND The aim of this study was to assess and compare the vertical/horizontal dimensions and occlusal accuracy of non-working/opposing casts obtained from three different impression materials and 3D print cast. MATERIAL AND METHODS Dentulous Master models simulating a case of a fixed dental prosthesis were mounted on an articulator (control group). Opposing mandibular casts obtained from three different impression materialsand 3-dimensional print constituted test groups , ,and , respectively. Three points, anterior vertical (AV), posterior vertical (PV), and anteroposterior (AP) were compared for dimensional accuracy among casts. Occlusal accuracy was analyzed on Medit Link software at 3 teeth (#13, #17, and #27). After calculating means for each group, the differences were calculated at probability value of P≤0.05 using the single-sample t test, ANOVA, and Tukey test. RESULTS The dimensions were significantly different from those of the mounted master models except in Gp AL(E) and Gp AL(F) at AV dimension and Gp AL(E) at AP dimension (P>0.05). A statistically significant difference of the error of means among the 4 tested groupswere detected only at 2 dimensions (AV and PV) between the Gp AL(E) and Gp 3D-C and between Gp AL(F) and Gp 3D-C groups. Other groups showed no significant differences. CONCLUSIONS The opposing casts obtained from the extended-pour alginate and alginate alternative impression materials showed higher occlusal accuracy compared to conventional alginate and 3D printed casts.
Topics: Humans; Alginates; Mandible; Models, Dental; Printing, Three-Dimensional; Software
PubMed: 37924203
DOI: 10.12659/MSM.941654 -
Journal of Clinical and Diagnostic... Nov 2013The purpose of the study is to quantify occlusal errors seen, during the processing of complete denture.
PURPOSE
The purpose of the study is to quantify occlusal errors seen, during the processing of complete denture.
MATERIAL AND METHODS
Maxillary and mandibular complete dentures were fabricated for 30 subjects. Anterior and posterior markings were made on articulator and the distance was measured from these points before and after processing of complete dentures. Occlusal errors following processing of complete dentures was determined by subjecting the values obtained to statistical analysis using paired t-test.
RESULTS
The results indicated the existence of discrepant amount of occlusal errors following processing of complete denture and statistical test applied was paired t-test, p-values obtained are, p=0.00 anterior reference markings and p=0.006 for posterior reference markings (p ≤ 0.001 highly significant).
CONCLUSION
The processing errors are inevitable. Hence for patient comfort, laboratory remounting is an important procedure that needs to be followed as a regular step after processing of each and every denture.
PubMed: 24392422
DOI: 10.7860/JCDR/2013/6183.3630 -
Computer Methods and Programs in... Jan 2021Magnetic resonance (MR) imaging is increasingly used in studies of speech as it enables non-invasive visualisation of the vocal tract and articulators, thus providing...
BACKGROUND AND OBJECTIVE
Magnetic resonance (MR) imaging is increasingly used in studies of speech as it enables non-invasive visualisation of the vocal tract and articulators, thus providing information about their shape, size, motion and position. Extraction of this information for quantitative analysis is achieved using segmentation. Methods have been developed to segment the vocal tract, however, none of these also fully segment any articulators. The objective of this work was to develop a method to fully segment multiple groups of articulators as well as the vocal tract in two-dimensional MR images of speech, thus overcoming the limitations of existing methods.
METHODS
Five speech MR image sets (392 MR images in total), each of a different healthy adult volunteer, were used in this work. A fully convolutional network with an architecture similar to the original U-Net was developed to segment the following six regions in the image sets: the head, soft palate, jaw, tongue, vocal tract and tooth space. A five-fold cross-validation was performed to investigate the segmentation accuracy and generalisability of the network. The segmentation accuracy was assessed using standard overlap-based metrics (Dice coefficient and general Hausdorff distance) and a novel clinically relevant metric based on velopharyngeal closure.
RESULTS
The segmentations created by the method had a median Dice coefficient of 0.92 and a median general Hausdorff distance of 5mm. The method segmented the head most accurately (median Dice coefficient of 0.99), and the soft palate and tooth space least accurately (median Dice coefficients of 0.92 and 0.93 respectively). The segmentations created by the method correctly showed 90% (27 out of 30) of the velopharyngeal closures in the MR image sets.
CONCLUSIONS
An automatic method to fully segment multiple groups of articulators as well as the vocal tract in two-dimensional MR images of speech was successfully developed. The method is intended for use in clinical and non-clinical speech studies which involve quantitative analysis of the shape, size, motion and position of the vocal tract and articulators. In addition, a novel clinically relevant metric for assessing the accuracy of vocal tract and articulator segmentation methods was developed.
Topics: Adult; Deep Learning; Dental Articulators; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Speech
PubMed: 33197740
DOI: 10.1016/j.cmpb.2020.105814 -
Life (Basel, Switzerland) Jan 2023A complex prosthodontic treatment is believed to be more successful when the condylar path is replicated using the articulator. However, there is an ongoing major...
Complicated Relationships between Anterior and Condylar Guidance and Their Clinical Implications-Comparison by Cone Beam Computed Tomography and Electronic Axiography-An Observational Cohort Cross-Sectional Study.
A complex prosthodontic treatment is believed to be more successful when the condylar path is replicated using the articulator. However, there is an ongoing major disagreement between the researchers as the exact relationship between the posterior and anterior determinants has not been clear. The purpose of this study was to investigate whether the protrusive movement of the mandible does correlate with the temporomandibular joint (TMJ) anatomy or with incised features. Subjects (15 males and 15 females) were qualified for this study based on an initial interview including the following criteria: age 21-23 (+/-1), no history of trauma, orthodontic treatment, or temporomandibular disorders (TMD). For each patient, the angle of the condylar path, incisal guidance angle (IGA), interincisal angle, as well as overbite and overjet were measured on cone beam computed tomography (CBCT). This was followed by the examination with the Modjaw electronic axiograph recording and calculating the functional sagittal condylar guidance angle (SCGA) for the right and left TMJ during the protrusion. The results show that the mean functional axiographic measurement of SCGA in protrusion significantly correlates with the TMJ anatomy presented on CBCT. Moreover, a significant correlation was found between the values of SCGA in the functional and anatomical measurements in all its variants. It turned out that, statistically, the AB measurement was the most accurate. Finally, results showed that incisal relationships of permanent teeth such as overbite, overjet, incisal guidance angle and interincisal angle do not correlate with TMJ anatomy, and therefore, regarding an analyzed study group, do not affect the TMJ formation in young adults.
PubMed: 36836692
DOI: 10.3390/life13020335 -
Beijing Da Xue Xue Bao. Yi Xue Ban =... Feb 2012To compare the difference of clinical and technical processes of full-crown restorations by using traditional and Triple-tray impression techniques, consumed materials... (Comparative Study)
Comparative Study
OBJECTIVE
To compare the difference of clinical and technical processes of full-crown restorations by using traditional and Triple-tray impression techniques, consumed materials and time estimated in every procedure of these two methods.
METHODS
Four veteran clinicians were selected to carry out full-crown restorative treatment for 124 patients (130 crowns). From one impression, dentists could make casts of prepared teeth and the opposing dentition and register the interocclusal relationship.After tooth preparation,Impregum Penta polyether impression was fabricated for 76 cases(80 crowns) by Triple-tray method and 48 cases (50 crowns)by conventional method. During the whole processes, the consumption of impression materials and plaster, the time of fitting on the articulator, manufacturing procedure and try-in in clinical practice were recorded. The differences of material and time consumption in every procedure of these two methods were evaluated by Independent-Samples t test.
RESULTS
The consumption of impression materials and plaster of Triple-tray impression technique was significantly less than that of traditional impression technique(P<0.01), and average time in every procedure of Triple-tray impression technique was remarkablely reduced compared with that of the traditional impression technique (P<0.01). Triple-tray impression technique reduces operating costs and the possibility of error.
CONCLUSION
Compared with traditional impression technique, Triple-tray impression technique could reduce the consumption of time and materials in clinical and technical processes.
Topics: Crowns; Dental Impression Materials; Dental Impression Technique; Humans; Models, Dental; Time Factors
PubMed: 22353920
DOI: No ID Found -
The Journal of Advanced Prosthodontics Oct 2023This study aimed to compare the accuracy of the conventional facebow system and the newly developed POP (PNUD (Pusan National University Dental School) Occlusal Plane)...
PURPOSE
This study aimed to compare the accuracy of the conventional facebow system and the newly developed POP (PNUD (Pusan National University Dental School) Occlusal Plane) bow system for occlusal plane transfer in asymmetric ear position.
MATERIALS AND METHODS
Two dentists participated in this study, one was categorized as Experimenter 1 and the other as Experimenter 2 based on their clinical experience with the facebow (1F, 2F) and POP bow (1P, 2P) systems. The vertical height difference between the two ears of the phantom model was set to 3 mm. Experimenter 1 and Experimenter 2 performed the facebow and POP bow systems on the phantom model 10 times each, and the transfer accuracy was analyzed. The accuracy was evaluated by measuring the angle between the reference virtual plane (RVP) of the phantom model and the experimental virtual plane (EVP) of the upper mounting plate through digital superimposition. All data were statistically analyzed using a paired -test ( < .05).
RESULTS
Regardless of clinical experience, the POP bow system (0.53° ± 0.30 (1P) and 0.19° ± 0.18 (2P) for Experimenter 1 and 2, respectively) was significantly more accurate than the facebow system (1.88° ± 0.50 (1F) and 1.34° ± 0.25 (2F), respectively) in the frontal view ( < .05). In the sagittal view, no significant differences were found between the POP bow system (0.92° ± 0.50 (1P) and 0.73° ± 0.42 (2P) for Experimenter 1 and 2, respectively) and the facebow system (0.82° ± 0.49 (1F) and 0.60° ± 0.39 (2F), respectively), regardless of clinical experience ( > .05).
CONCLUSION
In cases of asymmetric ear position, the POP bow system may transfer occlusal plane information more accurately than the facebow system in the frontal view, regardless of clinical experience.
PubMed: 37936837
DOI: 10.4047/jap.2023.15.5.271 -
The Journal of Prosthetic Dentistry Apr 2024The alignment of the maxillary and mandibular digital scans obtained with an intraoral scanner (IOS) generates digital interocclusal records. Although the accuracy of...
STATEMENT OF PROBLEM
The alignment of the maxillary and mandibular digital scans obtained with an intraoral scanner (IOS) generates digital interocclusal records. Although the accuracy of maxillary and mandibular digital scans obtained from an IOS is widely studied, the accuracy of digital interocclusal records obtained with them is not; even less studied is the accuracy (trueness and precision) of the alignment methods that are available to obtain them.
PURPOSE
The purpose of this in vitro study was to assess the precision under repeatability conditions (repeatability) of the different alignment methods used to obtain digital interocclusal records.
MATERIAL AND METHODS
Digital scans of maxillary and mandibular casts of a dentate healthy adult were acquired with an IOS. Casts were then mounted in maximum intercuspal position in a semi-adjustable mechanical articulator (1801 AR Model PSH Articulator), and left and right occlusal digital scans were acquired with the IOS. Occlusal digital scans were repeated 7 times under repeatability conditions. After obtaining each pair of occlusal digital scans, the software program of the IOS automatically aligned the maxillary and mandibular digital scans with occlusal digital scans (TRI method), resulting in 7 digital interocclusal records composed of aligned maxillary and mandibular digital scans and occlusal digital scans. All 7 sets of aligned digital scans were exported and realigned in a dental computer-aided design software program by means of global and reference alignment methods (EXO-B and EXO-R methods, respectively). To assess the repeatability, the 7 aligned digital scan sets of each group were repositioned in the common coordinate system by aligning maxillary digital scans, and repeatability was calculated in terms of the distance between the vertices of the mandibular digital scans for each of the possible nonrepeating combinations of pairs (C=21). The repeatability was tested by using the Kruskal-Wallis test for nonparametric distribution followed by the Mann-Whitney U test and Bonferroni correction for pairwise comparisons (α=.05).
RESULTS
The median with interquartile range for the TRI alignment method was 47 (27) μm for the EXO-B method 41 (25) μm and 16 (5) μm for EXO-R. The Kruskal-Wallis test showed statistical difference between test groups (P<.05). The post hoc Dunn test with Bonferroni adjustment detected significant statistical differences between the EXO-R-TRI (P<.001) and EXO-R-EXO-B (P<.001) alignment methods.
CONCLUSIONS
This study found that the alignment method could influence the repeatability of digital interocclusal records. The reference best-fit alignment method (EXO-R) provided better repeatability.
Topics: Imaging, Three-Dimensional; Models, Dental; Dental Impression Technique; Software; Computer-Aided Design
PubMed: 36115710
DOI: 10.1016/j.prosdent.2022.07.014 -
Beijing Da Xue Xue Bao. Yi Xue Ban =... Feb 2020To evaluate the three-dimensional (3D) reconstruction accuracy of the intercuspal occlusion (ICO) of the dental casts, by the dental articulator position method, and...
OBJECTIVE
To evaluate the three-dimensional (3D) reconstruction accuracy of the intercuspal occlusion (ICO) of the dental casts, by the dental articulator position method, and provide a reference for clinical application.
METHODS
The standard dental casts in ICO were mounted on average values articulator, and five pairs of milling resin cylinders were respectively attached to the base of both the casts. 100 μm articulating paper and occlusal record silicone rubber were used to detect the occlusal contact number between the posterior teeth of casts mounted on articulator in ICO. The occlusal contact numbers NA detected by the two methods were calculated simultaneously, as the reference. After the upper and lower casts were scanned separately, and the buccal data of casts in ICO were scanned with the aid of the dental articulator position, registration was carried out utilizing the registration software. Then the digital casts mounted in ICO as well as the buccal occlusal data were saved in standard tessellation language (STL) format. Geomagic Studio 2013 software was used to analyze the contact number NS between digital upper and lower casts by the "deviation analysis" function. The differences were compared between N and N, to evaluate the sensitivity and positive predict value (PPV) of the model scanner to reproduce the occlusal contact with the aid of dental articulator position. The distance D between the centers of the circles at the top surface of the upper and lower corresponding cylinders was obtained by the three-coordinate measuring system Faro Edge, as the reference value. The Geomagic Studio 2013 software was used to construct the cylinders of digital casts and the distance D between the centers of the circles at the top surface of the corresponding cylinders were measured, as the test value. The one-sample T test was used to analyze the variable differences between D and D.
RESULTS
The PPV of reproducing the occlusal contact point was 0.76 and sensitivity was 0.81. The distance error of the opposite cylinder was (0.232±0.089) mm. There was no statistical difference between the feature points 5-5', while there were statistical differences between the other feature points.
CONCLUSION
By the dental articulator position method, the model scanner reproduces the occlusal contact point with high sensitivity and PPV, and that meets clinical needs. Meanwhile, the distance between the feature points is greater than the reference value, which will lead to occlusal disturbance, and require clinical grinding.
Topics: Dental Articulators; Dental Occlusion; Imaging, Three-Dimensional; Jaw Relation Record; Models, Dental; Software
PubMed: 32071477
DOI: 10.19723/j.issn.1671-167X.2020.01.022 -
Journal of Pharmacy & Bioallied Sciences Nov 2021The aim of this study was to conduct a cross-sectional questionnaire-based survey concerning the practice of occlusal splint for treating temporomandibular disorders...
AIM
The aim of this study was to conduct a cross-sectional questionnaire-based survey concerning the practice of occlusal splint for treating temporomandibular disorders (TMDs) by the dental practitioners of Jabalpur.
MATERIALS AND METHODS
A questionnaire containing questions on diagnosis, treatment, and management of TMD was given to a total of 157 general dental practitioners in Jabalpur. The responses were collected; data analysis was done by Chi-square test.
RESULTS
Of the General Dental Practitioner's, nearly 78% of participants did not attend any continuing dental education on TMD per year. More than 10 years of experience (82%) was associated with increase in positive response for treatment of TMD patient. Both the diagnosis and treatment of TMD patient were done using combination methods. The duration of splint use was considered patient dependent (42.27%) irrespective of the years of practice. Soft splint was most commonly employed for treatment, and fabrication of splint was done on hinge and mean value articulator.
CONCLUSION
The knowledge of occlusal splint by general practitioners was found to be insufficient for treating TMDs.
PubMed: 35017933
DOI: 10.4103/jpbs.jpbs_157_21 -
BMC Oral Health Mar 2023Precise occlusal design of implant-supported fixed prostheses is difficult to achieve by the conventional wax-up method, often requiring chairside adjustments. The...
BACKGROUND
Precise occlusal design of implant-supported fixed prostheses is difficult to achieve by the conventional wax-up method, often requiring chairside adjustments. The computer-aided design (CAD) method is promising. This study aims to compare the occlusal contacts and clearance of posterior implant-supported single crowns designed by the CAD and conventional methods.
METHODS
Sample size calculation indicated fourteen samples per group. Two sets of type-IV plaster casts with a single implant analog inserted in the posterior teeth region were mounted as master casts in a mechanical articulator in maximal intercuspal position (MIP). Seven working cast sets were obtained from each master cast by a closed tray technique, and mounted in MIP. Two implant-supported single crowns were designed with an occlusal clearance to achieve light occlusal contact in each working cast set by CAD and conventional method, separately. For the CAD group, the crown was designed in digital models obtained by scanning the working casts. For the conventional group, wax-up of the crown was prepared on the working casts and scanned to generate a STL file. In the working and master casts, mean and minimum occlusal clearances in the designed occlusal contact area of the both finished prostheses were calculated using the occlusal clearance (OC) and occlusal record (OR) method. The prostheses' occlusion was evaluated in master casts.
RESULTS
For the evaluation in the working casts, both design methods had similar mean occlusal clearances by the OC method (195.4 ± 43.8 vs. 179.8 ± 41.8 μm; P = 0.300), while CAD group resulted in a significantly larger minimum occlusal clearance in the designed occlusal contact area (139.5 ± 52.3 vs. 99.8 ± 43.8 μm; P = 0.043). Both design methods had similar mean and minimum occlusal clearances by the OR method (P > 0.05). For the evaluation in the master casts, both design techniques had similar mean and minimum occlusal clearances, number and distribution of occlusal contacts, and lateral interference ratios (P > 0.05).
CONCLUSION
Occlusal contact and clearance of posterior implant-supported single crowns designed by the CAD method can be at least as good as those designed by the conventional wax-up method.
Topics: Humans; Crowns; Computer-Aided Design; Dental Occlusion; Research Design; Dental Impression Technique; Dental Prosthesis Design
PubMed: 36918877
DOI: 10.1186/s12903-023-02847-w