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The Journal of Advanced Prosthodontics Dec 2021The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach...
PURPOSE
The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach (CF) and a protocol using 3D printed casts (PC).
MATERIALS AND METHODS
A titanium implant was inserted at position of lower right first molar in a typodont. The implant position was scanned using an intraoral scanner and SICs were fabricated accordingly. Ten crowns (CF; n = 10) were subject to a digital cast-free workflow without any labside occlusal and interproximal modifications. Ten other identical crowns (PC) were adjusted to 3D printed casts before delivery. All crowns were then adapted to the testing model, simulating chair-side adjustments during clinical placement. Adjustment time, quantity of adjustments, and contact relationship were assessed. Data were analyzed using SPSS software ( < .05).
RESULTS
Median and interquartile range (IQR) of clinical adjustment time was 02:44 (IQR 00:45) minutes in group CF and 01:46 (IQR 00:21) minutes in group PC. Laboratory and clinical adjustment time in group PC was 04:25 (IQR 00:59) minutes in total. Mean and standard deviation (±SD) of root mean squared error (RMSE) of quantity of clinical adjustments was 45 ± 7 µm in group CF and 34 ± 6 µm in group PC. RMSE of total adjustments was 61 ± 11 µm in group PC. Quality of occlusal contacts was better in group CF.
CONCLUSION
Time effort for clinical adjustments was higher in the cast-free protocol, whereas quantity of modifications was lower, and the occlusal contact relationship was found more favourable.
PubMed: 35003551
DOI: 10.4047/jap.2021.13.6.351 -
Journal of Dentistry Jan 2023This prospective crossover clinical trial aimed to compare the complete-digital and -analog workflows in terms of occlusal adjustment of 3-unit tooth-supported fixed... (Clinical Trial)
Clinical Trial
AIM
This prospective crossover clinical trial aimed to compare the complete-digital and -analog workflows in terms of occlusal adjustment of 3-unit tooth-supported fixed dental prostheses, operator, and patient preferences.
MATERIALS AND METHOD
This study included twelve patients receiving fourteen 3-unit posterior FDPs. 2 FDPs were made for each restoration site: one fabricated in complete-digital workflow comprising intraoral scan with static bite registration (Trios 3) and a monolithic zirconia FDP (test); the other fabricated in complete-analog workflow comprising conventional impression/face-bow transfer and a porcelain-fused-to-metal FDP (control). The FDPs (n=28) were intraorally/provisionally fixed, and quadrant-like intraoral scans were taken for every FDP before & after their occlusal adjustments. Pre- and post-adjustment scans of each FDP were then superimposed using best-fit alignment (GOM Inspect) to measure the volumetric occlusal adjustment amount (mm) (3Matic) (Mann Whitney U, α=0.05). The patient and operator experience for digital and analog workflows were evaluated using visual analog scales (Wilcoxon test, α=0.05).
RESULTS
Mean occlusal adjustments were 7.63 mm [±7.02] and 25.95 mm [±39.61] for test and control groups, respectively. The volumetric adjustment difference was clinically noticeable but not significant (P=0.12). The impression and digital workflow adjustment were perceived more favorably by both operator (P=0.003, P=0.046, respectively) and the patients (P=0.003, P=0.002, respectively).
CONCLUSIONS
Within the limitations of this clinical study, the complete digital workflow with digital static bite-registration provided high occlusal accuracy for short-span tooth-supported FDPs. In addition, the patient and operator preferences significantly favored the digital workflow.
CLINICAL SIGNIFICANCE
Complete-digital workflow employing intraoral scanning and model-free fabrication of monolithic-Zr short-span tooth-supported FDPs offers an effective treatment modality with sufficient occlusal accuracy. Therefore complete-digital workflow is a valid alternative for complete-analog workflow comprising conventional impression, face-bow transfer, and use of a semi-adjustable articulator.
Topics: Humans; Computer-Aided Design; Dental Prosthesis Design; Occlusal Adjustment; Prospective Studies; Workflow; Zirconium; Cross-Over Studies
PubMed: 36403691
DOI: 10.1016/j.jdent.2022.104365 -
Clinical Oral Investigations Jul 2021To evaluate the precision of aligner (Invisalign®) treatment with the current material (SmartTrack®) in achieving expansion or contraction of the maxilla and occlusal...
OBJECTIVES
To evaluate the precision of aligner (Invisalign®) treatment with the current material (SmartTrack®) in achieving expansion or contraction of the maxilla and occlusal contacts as simulated in the proprietary planning software (ClinCheck®, CC).
MATERIALS AND METHODS
Thirty patients thus treated were retrospectively evaluated. Four maxillary models were analyzed per patient: a pretreatment model, a scan-based CC model, a posttreatment clinical model, and a CC model reflecting the treatment outcome as initially simulated. Thirteen transverse parameters were measured on each model separately by two investigators. Occlusal contacts were also analyzed.
RESULTS
The measuring method was validated by both investigators arriving at similar results for the effectiveness by which the simulated treatment goals had been clinically achieved. Significant differences (p < 0.05; Wilcoxon signed-rank test) were observed for transfer precision from the casts to the planning software and between the simulated and clinical outcomes. Intense occlusal contacts in the simulations materialized less common (≈ 2%) than ideal contacts (≈ 60%) in the clinical outcomes.
CONCLUSIONS
The effectiveness of achieving the simulated transverse goals was 45% and was generally not found to be better with SmartTrack® than with the previously used Ex30® material. Out of 100 simulated occlusal contacts, 40 will never materialize, and achieving around 60 will adequately ensure a clinically favorable contact pattern.
CLINICAL RELEVANCE
With the caveat that any overcorrection will to some extent reduce the precision, it seems perfectly possible to make deliberate use of overcorrection in current aligner therapies for transverse maxillary expansion or contraction.
Topics: Humans; Malocclusion; Maxilla; Occlusal Adjustment; Orthodontic Appliances, Removable; Palatal Expansion Technique; Retrospective Studies
PubMed: 33474622
DOI: 10.1007/s00784-021-03780-4 -
BDJ Open May 2023To measure the required clinical time and volume of occlusal adjustment when the maxillary cast is positioned in a virtual articulator using one of three methods:...
OBJECTIVE
To measure the required clinical time and volume of occlusal adjustment when the maxillary cast is positioned in a virtual articulator using one of three methods: digitization of a facebow-mounted mechanical articulator (group A), virtual Bonwill triangle (group B) or a 3D face scan (group F).
MATERIALS AND METHODS
In this randomized, triple-blind, crossover trial; 11 participants were enrolled. Every participant had one molar indicated for a single crown restoration. Three crowns were designed and milled for every participant molar totaling 33 crowns. Each of the three crowns was fabricated with the participant's casts virtually mounted utilizing a different method. An impression was taken of the crown in place before occlusal adjustment. The occlusal adjustment was then performed and timed with the three crowns in the different groups. After the occlusal adjustment, an impression of the adjusted crown was taken. The pre-adjustment and post-adjustment impressions were digitally superimposed and the volume difference was measured. The Kruskal-Wallis test was used to compare the groups.
RESULTS
Group A showed the shortest mean adjustment time (3:44.59 ± 3:39.07) followed by group F (4:30.09 ± 2:01.50) and group B (4:35.30 ± 2:32.33). The mean adjustment volume for group A was (28 ± 19.1 mm) followed by group F (30.5 ± 18.8 mm) and group B (40.6 ± 29.5 mm). Different virtual mounting methods had no statistically significant effect on adjustment time (P-value = 0.538) or adjustment volume (P-value = 0.490).
CONCLUSIONS
A simplified approach in virtual articulator mounting appears to be justified in the construction of a single full-coverage prosthesis. Added labor, time and cost of more elaborate virtual mounting methods seem to be counterproductive.
PubMed: 37164989
DOI: 10.1038/s41405-023-00146-8 -
International Journal of Computerized... Sep 2022With the development of new materials, 3D printing has had an immense impact on dentistry. The latest innovations are the direct manufacturing of temporary and permanent...
AIM
With the development of new materials, 3D printing has had an immense impact on dentistry. The latest innovations are the direct manufacturing of temporary and permanent crown and bridge restorations, inlays, onlays, and veneers. In the present case report, 3D-printing technology was used to control and adjust the occlusal rehabilitation with 3D-printed crowns.
MATERIALS AND METHODS
A 44-year-old male patient with pathologic dental attrition visited the Department of Restorative Dentistry at the University of Würzburg (Würzburg, Germany). The attrition process was far advanced, and no conventional conservative therapy was indicated. For the rehabilitation of the tooth substance loss, dental height, and appearance, a permanent solution with dental crowns was elected. After the preparation, the restorations were constructed digitally. For the control of the occlusal height, appearance, and color, the restorations were fabricated with a 3D printer and temporarily cemented. The crowns showed a high precision, and only minimal occlusal corrections were needed. After a trial period of 2 weeks and another fine occlusal adjustment, the temporary crowns were removed and scanned. The data were matched to the original construction file, which could be used to optimize the final rehabilitation. The final restorations were made of monolithic zirconia, with only minimal occlusal corrections required.
CONCLUSION
At the present time, dentistry is experiencing a great shift toward new and interesting production solutions with 3D-printing technologies. Such technologies give dentists the ability to create more predictable and cost-effective treatments. 3D printing is already being used to create temporary and definitive dental crowns as well as complex treatments, as is shown in the present case report. (Int J Comput Dent 2022;25(3):325-332; doi: 10.3290/j.ijcd.b3380909).
Topics: Adult; Computer-Aided Design; Crowns; Dental Prosthesis Design; Humans; Male; Occlusal Adjustment; Printing, Three-Dimensional; Stereolithography
PubMed: 36125805
DOI: 10.3290/j.ijcd.b3380909 -
Heliyon May 2022The periodontal ligaments are very important sensory organ for our daily life such as perception of food size or hardness, determination of jaw position, and adjustment...
The periodontal ligaments are very important sensory organ for our daily life such as perception of food size or hardness, determination of jaw position, and adjustment of masticatory strength. The sensory properties of the periodontal ligament, especially those of the maxillary and mandibular molars, have not yet been fully investigated. Somatosensory evoked magnetic fields (SEFs) can be measured and evaluated for latency and intensity to determine the sensory transmission characteristics of each body parts. However, previous reports on SEFs in the oral region have only reported differences in upper and lower gingival and lip sensations. In this study, the aim was to clarify these sensory characteristics by measuring SEFs during mechanical stimulation of the periodontal ligament in the maxillary and mandibular first molars. Somatosensory evoked magnetic fields were measured in the contralateral hemispheres of 33 healthy volunteers. Mechanical stimulation of the maxillary and mandibular right first molars, and the left wrist was performed with a specific handmade tool. The first peak latency for the mandibular first molars was 41.7 ± 5.70 ms (mean ± SD), significantly shorter than that for the maxillary first molars at 47.7 ± 7.36 ms. The peak intensity for the mandibular first molars was 13.9 ± 6.06 nAm, significantly larger than that for the maxillary first molars at 7.63 ± 3.55 nAm. The locations in the contralateral hemispheres showed no significant difference between the maxillary first molars and mandibular first molars. These locations were more anteroinferior and exterior than that of the wrist, as suggested by the brain homunculus. Neural signals from the mandibular periodontal ligaments pass faster and more intensely to the central nervous system than those from the maxillary periodontal ligaments, and may preferentially participate in adjustment of the occlusal force and the occlusal position.
PubMed: 35620631
DOI: 10.1016/j.heliyon.2022.e09464 -
The Journal of Prosthetic Dentistry Nov 2023Standard-diameter dental implants are not always applicable because of anatomic limitations of the residual ridge. Thus, mini-implants have been increasingly used and... (Meta-Analysis)
Meta-Analysis Review
STATEMENT OF PROBLEM
Standard-diameter dental implants are not always applicable because of anatomic limitations of the residual ridge. Thus, mini-implants have been increasingly used and offer an alternative. However, data regarding prosthetic complications, maintenance factors, and clinical outcomes are limited.
PURPOSE
The purpose of this systematic review and meta-analysis was to compare prosthetic complications and maintenance events and clinical outcomes in residual ridges rehabilitated with mandibular implant overdentures (IODs) by using standard implants or mini-implants.
MATERIAL AND METHODS
Nine electronic databases were searched. Quantitative analyses to measure the risk ratio (RR) and standardized mean difference (SMD) were applied. Those methods were used to assess prosthetic complications and maintenance events (abutment adjustments, replacement of retentive element, occlusal adjustment, and overdenture fracture) and clinical outcomes related to postoperative pain, probing depth (PD), plaque index (PI), marginal bone loss (MBL), and implant survival rate.
RESULTS
Altogether, 7 publications were selected. Mini-implants presented reduced abutment adjustments (RR 0.23 [0.07, 0.73], P=.01), replacement of retentive element (RR 0.41 [0.31, 0.54], P<.001), occlusal adjustment (RR 0.53 [0.31, 0.91], P=.02), and overdenture fracture (RR 0.46 [0.23, 0.94], P=.03) compared with standard implants. Additionally, mini-implants presented lower values for PI at 6 months (SMD -0.27 [-0.47, -0.08], P=.006) and 12 months (SMD -0.25 [-0.46, -0.05], P=.01). No additional tangible differences were noted.
CONCLUSIONS
Mini-implants might be an alternative choice based on the number of prosthetic complications and maintenance events. This was also confirmed by the comparable clinical data between standard implants and mini-implants.
Topics: Humans; Dental Implants; Denture, Overlay; Dental Prosthesis, Implant-Supported; Alveolar Bone Loss; Mandible
PubMed: 35120735
DOI: 10.1016/j.prosdent.2021.11.010 -
Dental Materials Journal May 2021The attrition of enamel when opposed by ceramics is of great concern. The purpose of this study was to evaluate enamel wear against high translucent zirconia (Zr),...
The attrition of enamel when opposed by ceramics is of great concern. The purpose of this study was to evaluate enamel wear against high translucent zirconia (Zr), lithium disilicate (LD), gold (Au), and enamel (E) with different surface and contact conditions. The materials were divided into two groups: polished and ground (n=8 each). Two-body wear tests were performed against human enamel with vertical and horizontal, horizontal, and vertical repetitive movements as experiments 1 to 3 respectively. The surface roughness of all materials except Zr changed throughout the experiments. In experiment 1, Zr and Au showed less antagonist wear when polished than when ground. In experiment 2, polished groups showed less antagonist wear than ground groups in all materials. In experiment 3, Zr and LD exerted greater antagonist wear than E, regardless of Ra. These findings confirm the importance of polishing and occlusal adjustment of zirconia.
Topics: Ceramics; Dental Implants; Dental Polishing; Dental Porcelain; Humans; Materials Testing; Occlusal Adjustment; Surface Properties; Zirconium
PubMed: 33456027
DOI: 10.4012/dmj.2020-190 -
Zhonghua Kou Qiang Yi Xue Za Zhi =... Oct 2023Rehabilitation of complete edentulism is naturally related to temporomandibular joint (TMJ) since the proper functioning of complete denture depends on the normal... (Review)
Review
Rehabilitation of complete edentulism is naturally related to temporomandibular joint (TMJ) since the proper functioning of complete denture depends on the normal movement of TMJ. This review briefly introduced the design of occlusion in complete denture, characteristic of different occlusal patterns, and key points in registration of maxillomandibular relationship and occlusal adjustment. This review emphasized the significance of complete denture restoration to the health of TMJ.
Topics: Humans; Temporomandibular Joint; Temporomandibular Joint Disorders; Dental Occlusion; Occlusal Adjustment; Denture, Complete; Tooth Loss
PubMed: 37818531
DOI: 10.3760/cma.j.cn112144-20230730-00048 -
Journal of Dentistry Feb 2022The aim of this study was to compare the occlusal precision of computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) milled versus 3D printed...
OBJECTIVES
The aim of this study was to compare the occlusal precision of computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) milled versus 3D printed polymethylmethacrylate (PMMA) temporary prosthetic crowns , starting from the same digital CAD design.
MATERIALS AND METHODS
The study sample included 34 patients presenting 34 premolars in need of prosthetic rehabilitation: a total of 68 temporary crowns were manufactured, 34 of which milled and 34 printed. Immediately after manufacturing, the milled and printed provisionals were scanned with a desktop scanner (E1, 3Shape) to obtain STL files, that were superimposed to the original CAD design in order to identify the occlusal trueness (Analysis A). A second occlusal comparison was performed by scanning both kind of provisional after being placed intraorally with Trios scanner (3 Shape); intraoral scans were obtained in order to compare STL files of provisionals before and after occlusal adjustments (Analysis B). The occlusal trueness was identified at three reference points, P1 (vestibular cusp), P2 (palatal / lingual cusp), P3 (central fossa). The statistical analysis was performed using the R 3.4.3 statistical software (The R Foundation for Statistical Computing), with a significance level of p <0.05.
RESULTS
Overall, the printed crowns showed lower occlusal differences than the milled crowns, when compared to the CAD design file, with a statistically significant difference in P1 (difference of 0.025 ± 0.046 mm), P2 (difference of 0.027 ± 0 0.044 mm) and P3 ( difference of 0.018 ± 0.050) for Analysis A (p <0.05). In the Analysis B the direct comparison between the degree of average difference between the pre-adjustment and the post-occlusal adjustment of the milled and printed crowns shows that the printed crowns have lower occlusal mean difference values in all three points compared to the milled ones (difference of 0.146 ± 0.273 mm in P1, 0.285 ± 0.360 mm in P2 and 0.257 ± 0.277 mm in P3).
CONCLUSIONS
Within the limitation of this study, the data obtained showed a better occlusal surface dimensional accuracy of the 3D printed provisional crowns, when compared to the milled ones. Comparing the results obtained, it is possible to assume that the intraoral scans also had a contribution to occlusion, beside the manufacturing method. 3D printing can be successfully applied for manufacturing temporary PMMA crowns.
Topics: Computer-Aided Design; Crowns; Dental Prosthesis Design; Humans; Printing, Three-Dimensional
PubMed: 34910962
DOI: 10.1016/j.jdent.2021.103924