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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 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 -
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 -
Swiss Dental Journal Dec 2020Alfred Gysi was one of the most influential dental scientists of the last century. He is primarily considered a pioneer of modern articulation and occlusion theory, and...
Alfred Gysi was one of the most influential dental scientists of the last century. He is primarily considered a pioneer of modern articulation and occlusion theory, and several of his technical developments still bear his name. But what milieu did this dentist come from, what characterized his academic career and what research contributions did he make beyond the theory of articulation? How was he perceived by contemporary experts – as a researcher and as a colleague – and how can his scientific contributions be classified from today's perspective? These are precisely the questions that this article examines. The study is based on contemporary primary sources and on Gysi's own publications. In addition, a systematic re-analysis of the available secondary literature on the life and work of Alfred Gysi and on the history of the Zurich Dental Institute was carried out. The analysis shows that Gysi had a strong influence on contemporary dental prosthodontics and contributed considerably to its scientific character, especially due to the development of articulators and face bows, which received worldwide attention. But Gysi's scientific influence was by no means limited to prosthetics. Rather, he also provided important studies on caries and the dental pulp. Moreover, he published fundamental work on dental histopathology and microphotography. The current image of Gysi therefore needs to be revised. In view of the thematic breadth of his scientific contributions, Gysi is not only the most important prosthodontist of his time, but also one of the most versatile and innovative representatives in the history of Swiss dentistry.
PubMed: 33283993
DOI: No ID Found -
Cureus Dec 2022Introduction The importance of disocclusion in maintaining the health of the stomatognathic system is well established. However, the quantification of the same is...
Introduction The importance of disocclusion in maintaining the health of the stomatognathic system is well established. However, the quantification of the same is limited. This study aimed to determine the amount of posterior teeth disocclusion in protrusive and laterotrusive movements to establish the desired disocclusion in occlusal treatments. Materials and methods Twenty dentate subjects with Angles Class I occlusion, 18-30 years, were included in the study. Direct and indirect techniques measured disocclusion at the mesiobuccal cusp tip of the mandibular first molar. In the direct technique, the protrusive and working and nonworking records were made intraorally at the edge-to-edge position of maxillary and mandibular central incisors and canines, respectively. For the indirect technique, putty indices were made on a semi-adjustable articulator at 2 millimeters (mm) eccentric movements and the disocclusion records were then made intraorally using indices at the predetermined excursions. The records were trimmed, and the disocclusion was measured using an optical microscope (ZEISS Axio Imager 2; Carl Zeiss Microscopy Deutschland GmbH, Oberkochen, Germany). The comparison of disocclusion by both techniques was done by paired t-test. The Pearson correlation coefficient was used to analyze the statistical correlation between the disocclusion obtained during different excursive movements. Results The mean disocclusion obtained by direct technique was 1.72 ± .49 mm in protrusion, 1.19 ± .50 mm for the working side, and 2.54 ± .70 mm for the nonworking side. For the indirect technique, the disocclusion obtained was 1.22 ± .37 mm in protrusion, 8.57 ± .33 mm for the working side, and 1.71 ± .61 mm for the nonworking side. On comparison, there was a statistically significant difference (<0.05) seen for the values between the groups for direct and indirect subgroups except for the left working subgroup (>0.05) with higher values in the direct group. Conclusions The disocclusion obtained by the direct technique was higher than that obtained by the indirect technique. For both techniques, as the working side disocclusion increased, the nonworking side disocclusion also increased.
PubMed: 36627993
DOI: 10.7759/cureus.32306 -
Journal of Oral Rehabilitation Oct 2022Currently, there is a lack of data relating to dental practitioners' habits with clinical occlusal assessment and the application of practical techniques in occlusion.
Evaluation of dental practitioner habits with occlusal assessment and the clinical application of practical techniques in occlusion, amongst a cohort of participants based in the UK, South Africa, Malta and Malaysia.
BACKGROUND
Currently, there is a lack of data relating to dental practitioners' habits with clinical occlusal assessment and the application of practical techniques in occlusion.
OBJECTIVES
The aim of this study was to investigate habits with clinical occlusal assessment and the practical application of established concepts in occlusion amongst a cohort of international dentists.
METHODS
A piloted questionnaire with 20 statements was distributed by 5 recruiters. The recruiters were based in Malta (1), South Africa (1), Malaysia (1) and the UK (2). Outcomes were analysed using descriptives, chi-squared and Fisher's exact test. All the analyses were carried out in Stata, Version 12. Significance was inferred at p < .05.
RESULTS
Four hundred thirty-five completed responses were included in the sample (response rate, 70.7%). Overall, high levels of agreement were reported with the provision of single-unit crown and onlay restorations (78.8%) and bridge prostheses (up to 3 units, 77.9%), respectively. One-third (33.6%) agreed to observing dynamic occlusal relationships during an adult patient dental examination, 40.7% reported using articulators for crown and bridge cases, and 25.1% agreed to taking facebow records. Under half (47.3%) of the dentists expressed dissatisfaction with their undergraduate training in occlusion, with no significant association with the variables of the number of years of experience, the country of practice or being in general practice (p ≥ .226).
CONCLUSION
The results indicate a disparity between traditionally taught and applied concepts in clinical occlusion and the undertaking of occlusal assessments and the management of occlusion in clinical practice.
Topics: Adult; Dentists; Habits; Humans; Malaysia; Malta; Professional Role; South Africa; United Kingdom
PubMed: 35851718
DOI: 10.1111/joor.13358 -
BMC Oral Health Nov 2021The scanning of plaster models for three-dimensional (3D) construction requires their rigid fixation in the intercuspal position. Factors such as installation, motion,...
PURPOSE
The scanning of plaster models for three-dimensional (3D) construction requires their rigid fixation in the intercuspal position. Factors such as installation, motion, and scanning procedures influenced the accuracy of this method, which ultimately influence the results. Therefore, the present study attempted to provide an optimal and accurate method with less complex procedures and a more accessible equipment for determining the intercuspal relation in the 3D occlusal construction of dental models.
METHODS
A pair of plastic mounting plates that could be directly attached to a mechanical articulator was designed and 3D printed. Nine axial hemispherical concaves were introduced on the axial surface of each plate. The rigidly fixed maxillary and mandibular dental models were scanned directly. The distances D between nine pairs of concaves on both mounting plates adhered to the maxillary and mandibular sections of the articulator were measured using the three-coordinate measuring machine Faro Edge as the reference. The present study comprised seven test groups varying in number and location. Assessing the reference points from each of the seven groups performed the 3D construction. The Geomagic Studio software was used to construct the concaves of digital casts, and the distances D between the pairs of concaves were measured as test values. Variable differences between D and D were analyzed.
RESULTS
An optimum distribution scheme was obtained for reference point registration by quantitatively evaluating accuracy levels of the 3D constructions of different reference point distribution patterns. This scheme can serve as a reference for related studies and dental clinic operations.
CONCLUSIONS
Three-dimensional construction of the intercuspal relation during scanning of the maxillary and mandibular models with an accuracy of 0.046 mm ± 0.009 mm can be achieved using the improved design of mounting plates.
Topics: Dental Articulators; Humans; Imaging, Three-Dimensional; Mandible; Models, Dental; Software
PubMed: 34732188
DOI: 10.1186/s12903-021-01919-z -
Journal of Clinical Medicine May 2022During prosthodontic treatment, the averaged values of the transversal condylar inclination (TCI) and the sagittal condylar inclination (SCI) are used for articulator...
BACKGROUND
During prosthodontic treatment, the averaged values of the transversal condylar inclination (TCI) and the sagittal condylar inclination (SCI) are used for articulator settings. This study evaluated different parameters of measurable mandibular movements according to skeletal classes.
METHODS
Seventy-five patients (mean age 30.8 ± 5.49) had a condylography using the Cadiax Compact device (Gamma Dental, Klosterneuburg, Austria) and cephalometric analysis performed. Statistical analysis was performed using R statistical software.
RESULTS
There was no statistical evidence to state that the value of SCI angle is different in I compared to II Skeletal Class. There were no statistically significant differences when comparing the I vs. III and II vs. III Skeletal Class. The lowest mean SCI angle values were found in subjects with Skeletal Class III. There were statistically significant differences in left-sided TCI between Class I and II. There was a statistically significant linear relationship between ANB angle value and SCI value.
CONCLUSIONS
Due to the wide individual variation in SCI and TCI values, it is advisable to use individual measurable parameters of mandibular movements during prosthetic reconstructions. The statistically significant relationship between SCI and ANB angle can be used to individualize the articulating parameters, especially in significant skeletal disproportions.
PubMed: 35566792
DOI: 10.3390/jcm11092664 -
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 -
Healthcare (Basel, Switzerland) Jun 2022The clinical remount procedure, which involves remounting the dentures on an articulator with interocclusal records, can effectively reduce occlusal discrepancies. This... (Review)
Review
The clinical remount procedure, which involves remounting the dentures on an articulator with interocclusal records, can effectively reduce occlusal discrepancies. This procedure can be applied not only to new dentures but also to those already in service; however, research in this field is still scarce. This narrative review aims to establish a hypothetical mechanism and possible indications and contraindications for this technique as a basis for further research. Current studies have revealed a high prevalence of malocclusion in delivered dentures. Performing a clinical remount on these existing dentures would enhance the oral function of the denture wearer and would enable effective and accurate correction of the accumulated errors in the jaw relationship in a stable working environment. This technique should be performed if a patient has poor masticatory function or occlusion-related complaints. However, performing a clinical remount on dentures with an excessive anterior-posterior discrepancy between the centric relation and the maximal intercuspal position or on dentures with extremely low occlusal vertical dimension, is considered less effective. The clinical remount procedure remains an essential skill both for fabricating quality dentures and maintaining those already in service.
PubMed: 35742118
DOI: 10.3390/healthcare10061067