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Journal of Oral Rehabilitation Mar 2024Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known.
OBJECTIVE
To determine the immediate effect of eccentric occlusal interferences on masticatory performance.
METHODS
This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi-adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1-week washout period was applied between tests.
RESULTS
Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p < .05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p < .05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p < .05). The chewing rate did not differ among conditions (p = .1944).
CONCLUSION
Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles.
CLINICAL TRIAL REGISTRATION
Brazilian Registry of Clinical Trials (RBR-8g5zfg8).
Topics: Humans; Dental Occlusion; Mandible; Mastication; Molar; Particle Size; Double-Blind Method
PubMed: 37964439
DOI: 10.1111/joor.13620 -
The Journal of Prosthetic Dentistry Nov 2023The introduction of digital technology in dentistry has resulted in a shift from conventional methods to digital techniques. However, mounting a digitized dental cast on...
STATEMENT OF PROBLEM
The introduction of digital technology in dentistry has resulted in a shift from conventional methods to digital techniques. However, mounting a digitized dental cast on a virtual articulator is challenging. Several techniques have been suggested to resolve this problem, but in the absence of a standardized method, digitized dental casts are often mounted arbitrarily on a virtual articulator.
PURPOSE
The purpose of this clinical study was to compare the accuracy of a novel virtual facebow transfer (VM) technique based on cone beam computed tomography (CBCT) with that of the conventional mounting (CM) technique using a facebow.
MATERIAL AND METHODS
Five repeated mountings were performed with each technique for 15 participants. In the CM group, dental casts were mounted using a facebow record and scanned for transmission to the virtual dental space. In the VM group, digital dental casts were mounted on the standard tessellation language file of a reference articulator by reconstructing a file of the participant's skull from CBCT data. In this group, a virtual facebow, prepared by scanning the articulator and facebow complex, was used. After the CM and VM casts had been aligned, the coordinates of target points set on the maxillary right central incisor, maxillary right first molar, and maxillary left first molar were determined, and the mean ±standard deviation distance between the target points was calculated to compare the precision of the techniques. Additionally, vectors of the target point on the maxillary right central incisor were compared to analyze the spatial difference between the techniques. Finally, the occlusal plane angle was calculated. For the correlation analysis of repeated measured data, a 1-way repeated measures analysis of variance (ANOVA) was first performed. The Kolmogorov-Smirnov test was performed to determine normality, and a paired t test and the Wilcoxon signed rank test were performed for normally and nonnormally distributed variables, respectively (α=.05).
RESULTS
The mean distance between target points was significantly greater in the CM group (4.72 ±1.45 to 5.17 ±1.54 mm) than in the VM group (2.14 ±0.58 to 2.35 ±0.60 mm) (P<.05). The standard deviation between target points was significantly greater in the CM group (1.60 ±0.64 to 2.30 ±0.87 mm) than in the VM group (0.74 ±0.23 to 1.12 ±0.45 mm) (P<.05). The maxillary right central incisor was located more anteriorly in the VM group than in the CM (100%, P<.05) group. The occlusal plane angle was significantly steeper in the CM group than in the VM group (8.14 degrees versus 2.13 degrees, P<.05).
CONCLUSIONS
The VM technique was more precise than the CM technique. VM casts were positioned ahead of CM casts. Further, the occlusal plane angle tended to be steeper with the CM technique than with the VM technique.
PubMed: 37957064
DOI: 10.1016/j.prosdent.2023.08.025 -
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 -
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 -
International Journal of Computerized... Jun 2024There is an ongoing debate about the benefits of the facebow and individual articulator settings in prosthodontics when compared with simpler methods. The present study...
AIM
There is an ongoing debate about the benefits of the facebow and individual articulator settings in prosthodontics when compared with simpler methods. The present study aims to determine whether the implementation of novel algorithmic articulator concepts may be an alternative to avoid dynamic interference contacts during the design process of fixed posterior restorations, and to what extent the occlusal morphology of the restoration is affected.
MATERIALS AND METHODS
From a chairside CAD database, a total of 50 clinical patient cases documenting 61 planned fixed restorations in the posterior tooth region were selected. A common CAD software program was used for the automated knowledge-based design process. When designing the restorations, functional concepts were applied, including the pure static occlusion, the average articulation, three different articulator settings as a control, and a combination of a broad range of articulation parameters (the full range dynamic articulation). The resulting dynamic contact points were compared both visually and metrically with a monitoring software program.
RESULTS
There is a highly significant difference in avoiding dynamic interference contacts when applying the full range dynamic articulation compared with the pure static occlusion (P < 0.001) and the average articulation (P < 0.001). Furthermore, the superimposition revealed that the surface of the restorations showed nearly no visual morphologic changes after virtually grinding-in the interpenetrating contact points.
CONCLUSION
The full range dynamic articulation can be used for the design of small fixed posterior restorations to avoid most dynamic interference contacts without the need for determining individual parameters for each patient.
Topics: Humans; Algorithms; Dental Prosthesis Design; Computer-Aided Design; Dental Occlusion; Dental Restoration, Permanent; Software; Dental Articulators
PubMed: 37823544
DOI: 10.3290/j.ijcd.b4494379 -
The Saudi Dental Journal Sep 2023Digitalized workflow eliminates the need for the tray, impression materials, its decontamination, packaging and shipping, pouring with plaster, cast fabrication,...
Digitalized workflow eliminates the need for the tray, impression materials, its decontamination, packaging and shipping, pouring with plaster, cast fabrication, mounting in an articulator, reducing storage spaces, and the risks of any loss or fracture of the plaster model is overcome by archiving on the computer. This clinical investigation aimed to evaluate the effectiveness of the fully digitalized rehabilitation [implant-supported prosthesis] method in partially edentulous patients and with TMD, using advanced software. Twelve patients requiring implant-supported prosthesis in the mandibular molar area with Temporomandibular disorders [TMD] were selected. The fully digitalized rehabilitation method with advanced software was used for rehabilitation. For each subject, Optical impressions, CBCT scan, and Digital recording of jaw movement data. Guided implant surgery and digitalized prosthetic rehabilitation; were performed. The effectiveness of the digitalized workflow was assessed by evaluating the changes in the joint symptoms before and after the end of the treatment, changes in the electromyographic tracings, the precision of the prosthetic artefact, assessed through the amount of chair adjustment operating time and the number of retouching/ modifications to be carried out before the completion of the work. The results showed that the mean operative time required in 12 patients was 9.42 min, significantly less than the time recorded in previous studies when the medium mean was 16.00 min. The mean number of touch-ups [adjustments] was less than 3, most of which were on the interproximal surfaces. There were no significant changes recorded in the electromyography tracings. There were also no changes in joint symptoms. It was found that this way of working was entirely reliable and significantly reduced operating times and the number of appointments. Digital flow is beneficial ei dysfunctional patients, not about improvements in temporomandibular symptoms but in times of operability and prosthetic retouching.
PubMed: 37817790
DOI: 10.1016/j.sdentj.2023.05.024 -
Journal of Esthetic and Restorative... Jan 2024Complete arch implant rehabilitation necessitates meticulous treatment planning and high-level collaboration between surgical and prosthetic dental teams. Emerging...
OBJECTIVE
Complete arch implant rehabilitation necessitates meticulous treatment planning and high-level collaboration between surgical and prosthetic dental teams. Emerging virtual technologies hold considerable promise in streamlining this process. The aim of this article is to extend recommendations to clinicians venturing into the virtual patient-assisted esthetic implant rehabilitation workflow.
OVERVIEW
This article summarizes recommendations for virtual patient-assisted esthetic implant rehabilitation in the following five aspects: three-dimensional data handling and superimposition, occlusion and virtual articulator integration in creating virtual patients, streamlined face- and prosthetic-driven surgical planning, reuse of presurgical data ("Copy & Paste"), and final impression for passive fitting of final restoration. To illustrate these principles, a case with complete-mouth implant rehabilitation completed within six visits using this virtual patient workflow is presented.
CONCLUSION
The virtual patient workflow serves as an invaluable tool to perform treatment planning, enhance efficiency, and ensure predictable outcomes in esthetic complete arch implant rehabilitation.
CLINICAL SIGNIFICANCE
Virtual workflows are increasingly prevalent in esthetic implant rehabilitation. Nevertheless, these workflows necessitate a distinct set of knowledge and tools divergent from conventional dentistry practices. This article offers guidelines and recommendations for dental clinicians who are new to this field.
Topics: Humans; Computer-Aided Design; Dental Prosthesis, Implant-Supported; Esthetics, Dental; Dental Implants; Workflow
PubMed: 37792734
DOI: 10.1111/jerd.13142 -
The Journal of Prosthetic Dentistry Sep 2023Although different digital occlusal analyzers have been marketed, comparative studies are lacking.
STATEMENT OF PROBLEM
Although different digital occlusal analyzers have been marketed, comparative studies are lacking.
PURPOSE
The purpose of this in vitro study was to compare the repeatability and reproducibility of 2 different digital occlusal analyzers (T-Scan and OccluSense) for measuring the right- and left-side balance of occlusal contact forces.
MATERIAL AND METHODS
The repeatability and reproducibility of the 2 digital occlusal analyzers for measuring the balance of occlusal contact forces were determined and compared by using the Gauge Repeatability and Reproducibility tests based on the International Organization for Standardization (ISO), ISO 5725-2 and ISO 5725-3 standards. Ten different dental casts were mounted in the maximum intercuspation position on a semi-adjustable articulator. Then, the balance of occlusal contact forces in each of the 10 articulated dental casts was measured 24 times with each of the 2 digital occlusal analyzers. In addition, as the OccluSense, unlike the T-Scan, does not have a centering support for the piezoelectric film sensor, measurements with it were performed without and with a custom-designed and manufactured centering support. Finally, the repeatability and reproducibility of both digital occlusal analyzers were determined and compared using the Gauge Repeatability and Reproducibility tests.
RESULTS
The repeatability and reproducibility tests revealed that only 0.8% of the variance of the measurements obtained with the T-Scan was due to repeatability and reproducibility (0.4% repeatability, 0.4% reproducibility). In contrast, 12% of the variance of the measurements obtained with the OccluSense was due to repeatability and reproducibility (2.2% repeatability, 9.8% reproducibility). However, when using OccluSense with the centering support, the variance decreased to 6.4% (2.8% repeatability, 3.6% reproducibility). According to the Automotive Industry Action Group classification, the repeatability and reproducibility of the T-Scan were good, those of the OccluSense poor, and those of the OccluSense with the centering support medium.
CONCLUSIONS
The repeatability and reproducibility of the T-Scan were significantly better than those of the OccluSense for measuring the balance of occlusal contact forces. Furthermore, the repeatability and reproducibility of the OccluSense were significantly improved when used with a device to center the piezoelectric film sensor between the incisors. Nevertheless, the repeatability and reproducibility of the T-Scan were better.
PubMed: 37661548
DOI: 10.1016/j.prosdent.2023.07.026 -
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 -
Journal of Dentistry Oct 2023A digital workflow for implant-supported fixed complete prostheses (ISFCP) using photogrammetry (PG), virtual articulator (VA), and virtual facebow (VF) data remains a...
BACKGROUND
A digital workflow for implant-supported fixed complete prostheses (ISFCP) using photogrammetry (PG), virtual articulator (VA), and virtual facebow (VF) data remains a challenge.
METHODS
The novel ISFCP technique included four steps: (1) formation of a dynamic virtual patient, (2) integration of PG data, (3) fabrication of a diagnostic ISFCP, and (4) fabrication of a definitive ISFCP and test of the deviation.
RESULTS
Dynamic virtual patients were formed by integrating PG, VA, and VF data. The cumulative root mean square deviation between the designed data and actual definitive prosthesis was 140.4 µm.
CONCLUSIONS
The novel technique for ISFCP fabrication described in this paper can help optimise the clinical efficiency and quality of ISFCP but requires an initial learning curve.
CLINICAL SIGNIFICANCE
This technique provides a direct workflow, using PG, VA, and VF data, to fabricate ISFCP based on the provisional restoration.
Topics: Humans; Dental Prosthesis Design; Dental Implants; Dental Prosthesis, Implant-Supported; Workflow; Computer-Aided Design
PubMed: 37574104
DOI: 10.1016/j.jdent.2023.104649