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Journal of Clinical Medicine May 2022Information about full-digital protocols for bite registration with intraoral scanners on multiple implants in the edentulous jaw is scarce. The purpose of this...
OBJECTIVE
Information about full-digital protocols for bite registration with intraoral scanners on multiple implants in the edentulous jaw is scarce. The purpose of this comparative in vivo study was to investigate the reliability and time efficiency of a novel full-digital bite registration technique for the manufacture of full-arch maxillary fixed implant prostheses.
MATERIAL AND METHODS
In ten patients, a full-arch maxillary fixed implant prosthesis was manufactured on multi-unit abutment level through an analog prosthetic workflow. The bite registration was performed with use of a screw-retained polymethyl methacrylate (PMMA) verification jig with detachable wax rim. To articulate the definitive edentulous maxillary implant cast in centric relation at the appropriate occlusal vertical dimension (OVD) to the mandibular antagonist cast, a type II articulator (Artex, Amann Girrbach) was used. Three to six months later, a full-digital bite registration was performed with use of dual-function scan bodies and bilateral connected bite pillars. The bite pillars screwed into the scan bodies were used to adjust and articulate the edentulous maxillary implant arch to the mandibular antagonist arch at the defined OVD. Treatment time for analog and digital bite registration technique was measured in each patient. The reliability of the digital bite registration technique was evaluated by 3D comparison of two sets of stereo lithographic (STL) files obtained from each patient. The three-dimensional deviation was defined along the X-, Y- and -axes (Geomagic Control X, 3D Systems Inc., Rock Hill, SC, USA).
RESULTS
The treatment time for digital bite registration using dual-function scan bodies and bite pillars was significantly shorter than analog bite registration with verification jig and wax rim (60.30%, SD 5.72%). Minor differences between the two techniques were observed with a linear deviation range of 1115 µm (SD 668 µm) overall, 46.2 µm (SD 731.3 µm) along the -axis, -200.3 µm (SD 744.3 µm) along the -axis and 67.1 µm (SD 752.2 µm) along the -axis. Bilateral balanced contacts were registered in all patients during full-digital bite registration.
CONCLUSIONS
The novel digital bite registration technique with dual-function scan bodies and bite pillars allows for a full-digital workflow for full-arch implant supported restorations. The digital bite workflow was 60% faster, and the overall deviation was around 1 mm, which can be considered clinically acceptable.
PubMed: 35629010
DOI: 10.3390/jcm11102882 -
Journal of Indian Prosthodontic Society 2021The Aim of the study was to evaluate the reproducibility of condylar inclination values obtained using three different interocclusal recording materials in Hanau... (Randomized Controlled Trial)
Randomized Controlled Trial
Comparative evaluation of condylar guidance obtained by three different interocclusal recording materials in a semi-adjustable articulator and digital panoramic radiographic images in dentate patients: An study.
AIM
The Aim of the study was to evaluate the reproducibility of condylar inclination values obtained using three different interocclusal recording materials in Hanau Wide-Vue semi-adjustable articulator and to compare those values of condylar inclination with panoramic radiographic images.
SETTINGS AND DESIGN
In Vivo Comparative study.
MATERIALS AND METHODS
The clinical trial was carried out in the Department of Prosthodontics, M. R Ambedkar Dental College and Hospital, Bengaluru. A total of 30 dentulous subjects aged between 20 and 40 years were selected, without any signs and symptoms of temporomandibular joint disorders. With the help of a custom-made protrusive guide, protrusive records for three materials were made. These records were used for programming the articulator and the respective horizontal condylar inclination (HCI) value, and panoramic radiographs were made. The values obtained were statistically analyzed.
STATISTICAL ANALYSIS USED
Independent t-test, multiple comparisons using Bonferroni method followed by Analysis of variances (ANOVA) were used.
RESULTS
Among each pair of groups there exists a significant difference, i.e., the mean condylar inclination (degree) was found to be statistically significant between wax and polyvinyl siloxane (P < 0.01) as well as between wax and polyether (P < 0.01). No significant difference was observed between polyvinyl siloxane and polyether (P > 0.05).
CONCLUSION
HCI values differed depending on the type of material employed. The study concluded that the protrusive condylar guidance angles obtained by panoramic radiograph can be used in programming the semi-adjustable articulator and among the materials polyether gave the highest Condylar Guidance values with less variability and wax gave lowest values with greater variation.
Topics: Adult; Dental Articulators; Humans; Jaw Relation Record; Mandibular Condyle; Radiography, Dental, Digital; Radiography, Panoramic; Reproducibility of Results; Young Adult
PubMed: 34810368
DOI: 10.4103/jips.jips_239_21 -
The Journal of Prosthetic Dentistry May 2023Some contemporary articulator systems claim to be highly precise in their interchangeability, with tolerances below 10 μm in vertical error; however, the claims have...
STATEMENT OF PROBLEM
Some contemporary articulator systems claim to be highly precise in their interchangeability, with tolerances below 10 μm in vertical error; however, the claims have not been independently verified.
PURPOSE
The purpose of this study was to investigate the interchangeability of calibrated semiadjustable articulators in service over time.
MATERIAL AND METHODS
A calibrated mounting articulator served as the master articulator, while the test groups were used articulators with a minimum of 1-year use by predoctoral dental students (n=10); used articulators with a minimum of 1-year use by prosthodontic residents (n=10); and new articulators (n=10). One set of mounted maxillary and mandibular master models was positioned in the master and test articulators. High-precision reference markers on the master models were used to determine interarch 3D distance distortions (dR, dR, and dR), interocclusal 3D distance distortion (dR), interocclusal 2D distance distortions (dx, dy, and dz), and interocclusal angular distortion (dθ) relative to the master articulator. All measurements were conducted three times using a coordinate measuring machine and then averaged to derive the final data set.
RESULTS
For interarch 3D distance distortion, the mean dR ranged from 4.6 ±21.6 μm for new articulators to 56.3 ±47.6 μm for articulators used by prosthodontic residents; mean dR ranged from 65 ±48.6 μm for new articulators to 119.0 ±58.8 μm for articulators used by prosthodontic residents; and mean dR ranged from 12.7 ±39.7 μm for articulators used by prosthodontic residents to 62.8 ±75.2 μm for new articulators. For interocclusal 3D distance distortion, the mean dR ranged from 21.5 ±49.8 μm for new articulators to 68.6 ±64.9 μm for articulators used by predoctoral dental students. For the 2D distance distortions, the mean dx ranged from -17.9 ±43.4 μm for articulators used by predoctoral dental students to -61.9 ±48.3 μm for articulators used by prosthodontic residents; mean dy ranged from 18.1 ±59.4 μm for new articulators to 69.3 ±115.1 μm for articulators used by prosthodontic residents; and mean dz ranged from 29.5 ±20.2 μm for new articulators to 70.1 ±37.8 μm for articulators used by prosthodontic residents. Mean dθ ranged from -0.018 ±0.289 degree for new articulators to 0.141 ±0.267 degree for articulators used by prosthodontic residents. One-way ANOVA by articulator type revealed statistically significant differences among the test groups for dR (P=.007) and dz (P=.011) only, where articulators used by prosthodontic residents fared significantly poorer than the other test groups.
CONCLUSIONS
The new and used articulators tested did not fulfill the manufacturer's claim of accuracy of up to 10 μm in the vertical dimension. Up to 1 year of time in service, none of the investigated test groups fulfilled the criterion for articulator interchangeability, even if the more lenient threshold of 166 μm were accepted.
PubMed: 37244795
DOI: 10.1016/j.prosdent.2023.04.009 -
British Dental Journal Sep 2014The aim of this study was to identify the communication methods and production techniques used by dentists and dental technicians for the fabrication of fixed prostheses...
AIM
The aim of this study was to identify the communication methods and production techniques used by dentists and dental technicians for the fabrication of fixed prostheses within the UK from the dental technicians' perspective. This second paper reports on the production techniques utilised.
MATERIALS AND METHODS
Seven hundred and eighty-two online questionnaires were distributed to the Dental Laboratories Association membership and included a broad range of topics, such as demographics, impression disinfection and suitability, and various production techniques. Settings were managed in order to ensure anonymity of respondents. Statistical analysis was undertaken to test the influence of various demographic variables such as the source of information, the location, and the size of the dental laboratory.
RESULTS
The number of completed responses totalled 248 (32% response rate). Ninety percent of the respondents were based in England and the majority of dental laboratories were categorised as small sized (working with up to 25 dentists). Concerns were raised regarding inadequate disinfection protocols between dentists and dental laboratories and the poor quality of master impressions. Full arch plastic trays were the most popular impression tray used by dentists in the fabrication of crowns (61%) and bridgework (68%). The majority (89%) of jaw registration records were considered inaccurate. Forty-four percent of dental laboratories preferred using semi-adjustable articulators. Axial and occlusal under-preparation of abutment teeth was reported as an issue in about 25% of cases. Base metal alloy was the most (52%) commonly used alloy material. Metal-ceramic crowns were the most popular choice for anterior (69%) and posterior (70%) cases. The various factors considered did not have any statistically significant effect on the answers provided. The only notable exception was the fact that more methods of communicating the size and shape of crowns were utilised for large laboratories.
CONCLUSION
This study suggests that there are continuing issues in the production techniques utilised between dentists and dental laboratories.
Topics: Communication; Dental Prosthesis Design; United Kingdom
PubMed: 25257017
DOI: 10.1038/sj.bdj.2014.644 -
Journal of Indian Prosthodontic Society Jun 2013Determination of condylar inclination is important when restoring the occlusal surfaces of teeth. It is important to know the changing trends in horizontal condylar...
UNLABELLED
Determination of condylar inclination is important when restoring the occlusal surfaces of teeth. It is important to know the changing trends in horizontal condylar inclination with age so as to have an idea about the cuspal morphology.
AIMS AND OBJECTIVES
a) to determine the effect of age changes in horizontal condylar inclination using articulator method and radiographic method (cephalometry) b) to compare the values of horizontal condylar inclination obtained using articulator method with that of cephalometric method c) to ascertain the symmetry of horizontal condylar angle on both right and left side on an articulator. 40 dentulous individuals with Angle's class I occlusion were selected for the study. They were divided into four groups Group I: 20-29 years, Group II: 30-39 years, Group III: 40-49 years, Group IV: 50-59 years. Horizontal condylar inclination was determined on right and left side for each individual using protrusive interocclusal record in a Dentatus (ARL) semiadjustable articulator. Cephalometric recording was carried out twice on the left side, once in centric occlusion position and then in protrusive position. The two radiographs were superimposed to draw a line connecting the shifting position of condylion on an acetate tracing paper. This line when joined with Frankfurt horizontal plane gives the horizontal condylar inclination. Analysis of variance (ANOVA) revealed that there was a significant difference in horizontal condylar angle values in all the four groups which were statistically significant. There is a decrease in horizontal condylar angle values from Group I to Group IV. Horizontal condylar values obtained by articulator method and cephalometric method showed no significant difference for all the four groups tested. When horizontal condylar values obtained on right and left sides of Dentatus articulator were compared there was not much of a significant difference. Horizontal condylar values showed a decreasing trend with increasing age, i.e, as age advances there is a flattening of condylar head. Both articulator and cephalometric method yielded no significantly different values and hence both the methods can be used for determining condylar inclination. The difference in values of horizontal condylar angle on right and left sides were insignificant.
PubMed: 24431719
DOI: 10.1007/s13191-012-0192-z -
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 -
Journal of Prosthodontic Research Oct 2022Acquiring adequate attached mucosa is important in restoring masticatory function with a removable dental prosthesis or dental implant. In patients with inadequate...
PURPOSE
Acquiring adequate attached mucosa is important in restoring masticatory function with a removable dental prosthesis or dental implant. In patients with inadequate attached mucosa, a free gingival graft (FGG) with a custom stent is used. However, it is challenging to apply the conventional method for fabricating a stent with a reshaped cast in patients with reconstructed mandibles because the reconstructed mandible has limitations due to a titanium mesh, skin flap, and unique bone morphology. In the present report, we have proposed a new design and fabrication process for a mucocompressive splint via medical engineering to acquire the attached mucosa for the prosthodontic treatment of reconstructed mandibles.
METHODS
Three-dimensional (3D) craniomandibular models were reconstructed from a computed tomography dataset after mandibular reconstruction. The dentition region was replaced with highly precise scan data of the dental casts using a 3D scanner. The alveolar ridge mucosa and teeth were ideally designed using the 3D model while referring to the anatomical structures. The jig used to fabricate the working dental cast with artificial gum in real space was designed and fabricated using a 3D printer. The alveolar ridge was altered into a simulated configuration on the articulator using a jig. A mucocompressive splint was fabricated on an altered dental cast. The splint was immediately seated on the mandible without any major adjustments after the FGG.
CONCLUSION
Adequate attached mucosa for the prosthodontic treatment of a reconstructed mandible was obtained by the pre-surgical fabrication of a mucocompressive splint through medical engineering.
Topics: Dental Implants; Humans; Mandible; Mandibular Reconstruction; Splints; Titanium
PubMed: 35067490
DOI: 10.2186/jpr.JPR_D_21_00160 -
The Angle Orthodontist 1996Two different articulator systems are commonly used by orthodontists to reveal the maxillomandibular relationship for improved diagnosis and treatment planning. The... (Comparative Study)
Comparative Study
Two different articulator systems are commonly used by orthodontists to reveal the maxillomandibular relationship for improved diagnosis and treatment planning. The purposes of the study were: (1) to compare the SAM and the Panadent articulator systems when recording condylar discrepancies for the same patient; (2) to evaluate the interchangeability of the SAM estimated facebow when mounting to the Panadent articulator; and (3) to evaluate the direction of condylar movement between centric relation (CR) and centric occlusion (CO). Maxillary and mandibular impressions, CO and CR bite registrations, and SAM and Panadent facebow recordings were taken for 37 patients. There were no statistically significant differences between the SAM and the Panadent systems (p > 0.05). However, the SAM facebow should not be used when mounting to the Panadent articulator. In most cases, the condyle moves down and back when the subject bites into maximum intercuspation.
Topics: Centric Relation; Dental Articulators; Dental Impression Technique; Dental Occlusion; Dental Occlusion, Centric; Equipment Design; Humans; Jaw Relation Record; Malocclusion; Mandible; Mandibular Condyle; Maxilla; Models, Dental; Movement; Patient Care Planning
PubMed: 8863965
DOI: 10.1043/0003-3219(1996)066<0293:RCMWTF>2.3.CO;2 -
Journal of Psycholinguistic Research Dec 2023Generalization in motor control is the extent to which motor learning affects movements in situations different than those in which it originally occurred. Recent data...
Generalization in motor control is the extent to which motor learning affects movements in situations different than those in which it originally occurred. Recent data on orofacial speech movements indicates that motor sequence learning generalizes to novel syllable sequences containing phonotactically illegal, but previously practiced, consonant clusters. Practicing an entire syllable, however, results in even larger performance gains compared to practicing just its clusters. These patterns of generalization could reflect language-general changes in phonological memory storage and/or inter-articulator coordination during motor sequence learning. To disentangle these factors, we conducted two experiments in which talkers intensively practiced producing novel syllables containing illegal onset and coda clusters over two consecutive days. During the practice phases of both experiments, we observed that, through repetition, talkers gradually produced the syllables with fewer errors, indicative of learning. After learning, talkers were tested for generalization to single syllables (Experiment 1) or syllable pairs (Experiment 2) that overlapped to varying degrees with the practiced syllables. Across both experiments, we found that performance improvements from practicing syllables with illegal clusters partially generalized to novel syllables that contained those clusters, but performance was more error prone if the clusters occurred in a different syllable position (onset versus coda) as in practice, demonstrating that inter-articulator coordination is contextually sensitive. Furthermore, changing the position of a cluster was found to be more deleterious to motor performance during the production of the second syllables in syllable pairs, which required talkers to store more phonological material in memory prior to articulation, compared to single syllables. This interaction effect reveals a complex interplay between memory storage and inter-articulator coordination on generalization in speech motor sequence learning.
Topics: Humans; Speech; Dental Articulators; Linguistics; Language; Speech Perception; Phonetics
PubMed: 37488461
DOI: 10.1007/s10936-023-09998-5 -
Case Reports in Dentistry 2022In this article, two cases with generalized dental wear and four cases with localized dental wear are reported. In some of the cases, the worn teeth were restored with...
BACKGROUND
In this article, two cases with generalized dental wear and four cases with localized dental wear are reported. In some of the cases, the worn teeth were restored with direct composite techniques with no mock-up and articulator mounting according to the canine rise method. This method is used without any change in the intercuspation of posterior teeth without a muscle relaxation appliance. It introduces a stable occlusal condition that can alter neuromuscular reflex activity, leading to improvements in certain muscle pain disorders. It is also used to protect the teeth and supporting structures from abnormal forces that might create a further breakdown and/or tooth wear.
METHODS
The first step of treatment in all the cases was a composite build-up for maxillary and mandibular canines to restrict and guide the horizontal and vertical jaw movements and create adequate space for restorations. The second step was the placement of direct or indirect restorations on upper and lower anterior teeth efficiently and accurately.
RESULTS
This method enhanced the esthetic outcomes in a conservative approach with no reduction in tooth material or time-consuming treatments.
CONCLUSIONS
This technique can be suggested for the treatment of worn teeth in patients with Angle's Cl I and Cl II classifications of malocclusion based on the follow-up results. It is not applicable for the treatment of worn teeth in patients with Angle's class III because occlusion is reversed, and canine teeth do not have guidance role. . This method significantly reduces the overall treatment time, and additional steps are required to restore the worn-out teeth and/or occlusion using the canine rise method.
PubMed: 35265380
DOI: 10.1155/2022/9949879