scholarly journals Color and Translucency Stability of Three-Dimensional Printable Dental Materials for Crown and Bridge Restorations

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 650
Author(s):  
Jong-Eun Kim ◽  
Won-Huy Choi ◽  
Dasun Lee ◽  
Yooseok Shin ◽  
Sung-Ho Park ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Dental Materials ◽  
Three Dimensional ◽  
Digital Light Processing ◽  
Color Changes ◽  
Repeated Measures Analysis ◽  
Color Differences ◽  
Distinct Color ◽  
Materials Used ◽  
And Storage

The purpose of this study was to examine and compare color and translucency stability of three-dimensional (3D) printable dental materials for crown and bridge restorations. Five different materials were investigated, and twelve disc-shaped specimens of two different thicknesses (1 and 2 mm) were prepared using a digital light processing 3D printer. Color measurements were made according to the CIELAB color scale (L*, a*, and b*) using a spectrophotometer 1 h, 1 day, 1 week, one month, and six months after post-curing of the materials, and the translucency parameter (TP) was calculated. The L*, a*, b*, and TP values were compared among the different materials and storage periods using repeated measures analysis of variance. Color and translucency changes of the specimens after the different storage periods were compared with 1 h measurements to determine whether they exceeded clinically perceivable thresholds. The L*, a*, b*, and TP values showed significant differences according to the storage periods, as well as among the materials. Until one month, some materials demonstrated distinct color differences, while others showed small color differences below a clinically perceivable threshold. The translucency differences were not clinically perceivable for any specimen. After six months, all specimens demonstrated large color changes, whereas the changes in translucency were relatively small. In conclusion, the color of 3D printable dental materials changed with time, and the differences varied with the materials used. On the contrary, the changes in translucency were small. Overall, the materials became darker, more yellowish, and more opaque after six months of water storage.

scholarly journals Cytocompatibility of 3D printed dental materials for temporary restorations on fibroblasts

2020 ◽  
Author(s):  
Jung-Hyun Park ◽  
Hyun Lee ◽  
Jong-Woo Kim ◽  
Ji-Hwan Kim
Keyword(s):  
3D Printing ◽  
Laser Scanning ◽  
Dental Materials ◽  
Three Dimensional ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
Control Group ◽  
Digital Light Processing ◽  
3D Printed ◽  
Materials Used

Abstract Background Three-dimensional (3D) printing is widely used in the fabrication of dental prostheses; however, the influence of dental materials used for 3D printing on temporary restoration of fibroblasts in tissues is unclear. Thus, the influence of different dental materials on fibroblasts were investigated. Methods Digital light processing (DLP) type 3D printing was used. Specimens in the control group were fabricated by mixing liquid and powder self-curing resin restoration materials. The temporary resin materials used were Model, Castable, Clear-SG, Tray, and Temporary, and the self-curing resin materials used were Lang dental, Alike, Milky blue, TOKVSO CUREFAST, and UniFast III. Fibroblast cells were cultured on each specimen and subsequently post-treated for analysis. Morphology of the adhered cells were observed using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM). Results CLSM and SEM cell imaging revealed that the 3D printed material group presented better cell adhesion with well-distributed filopodia compared to that in the conventional resin material group. Cell proliferation was significantly higher in the 3D printing materials. Conclusion This indicates that using resins fabricated by 3D printing technology rather than the ones fabricated by self-curing technology is recommended for the fabrication of dental temporary restorations.

The Spatial Dependency of Shoulder Muscle Demands for Seated Lateral Hand Force Exertions

2014 ◽  
Vol 30 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Alison C. McDonald ◽  
Elora C. Brenneman ◽  
Alan C. Cudlip ◽  
Clark R. Dickerson
Keyword(s):  
Repeated Measures ◽  
Muscle Activation ◽  
Three Dimensional ◽  
Emg Activity ◽  
Hand Position ◽  
Individual Muscle ◽  
Repeated Measures Analysis ◽  
Spatial Parameters ◽  
Shoulder Complex ◽  
The Right

As the modern workplace is dominated by submaximal repetitive tasks, knowledge of the effect of task location is important to ensure workers are unexposed to potentially injurious demands imposed by repetitive work in awkward or sustained postures. The purpose of this investigation was to develop a three-dimensional spatial map of the muscle activity for the right upper extremity during laterally directed submaximal force exertions. Electromyographic (EMG) activity was recorded from fourteen muscles surrounding the shoulder complex as the participants exerted 40N of force in two directions (leftward, rightward) at 70 defined locations. Hand position in both push directions strongly influenced total and certain individual muscle demands as identified by repeated measures analysis of variance (P< .001). During rightward exertions individual muscle activation varied from 1 to 21% MVE and during leftward exertions it varied from 1 to 27% MVE with hand location. Continuous prediction equations for muscular demands based on three-dimensional spatial parameters were created with explained variance ranging from 25 to 73%. The study provides novel information for evaluating existing and proactive workplace designs, and may help identify preferred geometric placements of lateral exertions in occupational settings to lower muscular demands, potentially mitigating fatigue and associated musculoskeletal risks.

3D Printing in Dentistry—State of the Art

2020 ◽  
Vol 45 (1) ◽  
pp. 30-40 ◽  
Author(s):  
A Kessler ◽  
R Hickel ◽  
M Reymus
Keyword(s):  
3D Printing ◽  
Clinical Application ◽  
Industrial Revolution ◽  
Rapid Development ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Fused Filament Fabrication ◽  
Digital Light Processing ◽  
Materials Used ◽  
Binder Jetting

SUMMARY Three-dimensional (3D) printing is a rapidly developing technology that has gained widespread acceptance in dentistry. Compared to conventional (lost-wax technique) and subtractive computer numeric controlled methods, 3D printing offers process engineering advantages. Materials such as plastics, metals, and ceramics can be manufactured using various techniques. 3D printing was introduced over three decades ago. Today, it is experiencing rapid development due to the expiration of many patents and is often described as the key technology of the next industrial revolution. The transition to its clinical application in dentistry is highly dependent on the available materials, which must not only provide the required accuracy but also the necessary biological and physical properties. The aim of this work is to provide an up-to-date overview of the different printing techniques: stereolithography, digital light processing, photopolymer jetting, material jetting, binder jetting, selective laser sintering, selective laser melting, and fused filament fabrication. Additionally, particular attention is paid to the materials used in dentistry and their clinical application.

scholarly journals A Review on the Biocompatibility of PMMA-Based Dental Materials for Interim Prosthetic Restorations with a Glimpse into Their Modern Manufacturing Techniques

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2894 ◽  
Author(s):  
Silviu Mirel Pituru ◽  
Maria Greabu ◽  
Alexandra Totan ◽  
Marina Imre ◽  
Mihaela Pantea ◽  
...  
Keyword(s):  
Dental Materials ◽  
Three Dimensional ◽  
Oral Epithelial Cells ◽  
Prosthetic Materials ◽  
Oral Environment ◽  
Pulp Cells ◽  
3D Printed ◽  
Manufacturing Techniques ◽  
Materials Used ◽  
Oral Epithelial

This paper’s primary aim is to outline relevant aspects regarding the biocompatibility of PMMA (poly(methyl methacrylate))-based materials used for obtaining interim prosthetic restorations, such as the interaction with oral epithelial cells, fibroblasts or dental pulp cells, the salivary oxidative stress response, and monomer release. Additionally, the oral environment’s biochemical response to modern interim dental materials containing PMMA (obtained via subtractive or additive methods) is highlighted in this review. The studies included in this paper confirmed that PMMA-based materials interact in a complex way with the oral environment, and therefore, different concerns about the possible adverse oral effects caused by these materials were analyzed. Adjacent to these aspects, the present work describes several advantages of PMMA-based dental materials. Moreover, the paper underlines that recent scientific studies ascertain that the modern techniques used for obtaining interim prosthetic materials, milled PMMA, and 3D (three-dimensional) printed resins, have distinctive advantages compared to the conventional ones. However, considering the limited number of studies focusing on the chemical composition and biocompatibility of these modern interim prosthetic materials, especially for the 3D printed ones, more aspects regarding their interaction with the oral environment need to be further investigated.

Citrate Storage Affects Thrombelastograph®Analysis

2000 ◽  
Vol 92 (5) ◽  
pp. 1242-1249 ◽  
Author(s):  
Vladimir Camenzind ◽  
Thomas Bombeli ◽  
Burkhardt Seifert ◽  
Marina Jamnicki ◽  
Dragoljub Popovic ◽  
...  
Keyword(s):  
Blood Coagulation ◽  
Analysis Of Variance ◽  
Whole Blood ◽  
Repeated Measures ◽  
Surgical Patients ◽  
Time Points ◽  
Prothrombin Fragment ◽  
Repeated Measures Analysis ◽  
Thrombin Activation ◽  
And Storage

Background Thrombelastograph analysis (TEG) is used to evaluate blood coagulation. Ideally, whole blood is immediately processed. If impossible, blood may be citrated and assessed after recalcification. No data describe the effect of such treatment and storage on TEG parameters. Methods Three studies were performed in 90 surgical patients. In 30 patients, blood was citrated (1:10, 0. 129 M) and recalcified (20 microl 2 M CaCl2 to 340 microl citrated blood), and TEG was performed with native blood and after recalcification after 0, 15, and 30 min of citrate storage. In another 30 patients, TEG was performed with citrated blood recalcified immediately and after 1-72 h storage. In a third study, thrombin-antithrombin complex, prothrombin fragment 1+2, and beta-thromboglobulin were measured (using enzyme-linked immunoabsorbant assay tests) at corresponding time points. Data were compared using repeated-measures analysis of variance and post hocpaired t tests. Results TEG parameters were different in recalcified citrated blood compared with native blood (P &lt; 0.05) and changed significantly during 30-min (P &lt; 0.025) and 72-h (P &lt; 0.001) citrate storage. TEG parameters measured between 1 and 8 h of citrate storage were stable. Thrombin-antithrombin complex and prothrombin fragment 1+2 values were not elevated in native blood. After 30 min of citrate storage a gradual thrombin activation was observed, as evidenced by increasing thrombin-antithrombin complex and prothrombin fragment 1+2 values (P &lt; 0.05). beta-Thromboglobulin level was increased after 2 and 8 h of citrate storage (P &lt; 0.01). Conclusions Analysis of native blood yields the most reliable TEG results. Should immediate TEG processing not be possible, citrated blood may be used if recalcified after 1-8 h.

The effect of valgus and varus femoral osteotomies on measures of anteversion in the dog

2017 ◽  
Vol 30 (03) ◽  
pp. 184-190 ◽  
Author(s):  
Rachel Adams ◽  
Brad Gilleland ◽  
Farrah Monibi ◽  
Samuel Franklin
Keyword(s):  
Repeated Measures ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Femoral Anteversion ◽  
Coxa Vara ◽  
Neck Shaft Angle ◽  
Repeated Measures Analysis ◽  
Shaft Angle ◽  
Coxa Valga ◽  
Head Neck

Summary Objective: To determine whether femoral osteotomies that change frontal plane alignment without affecting torsion influence anteversion and inclination. Methods: Femurs without deformity were scanned to create three-dimensional reconstructions. The femoral head-neck axis was identified by placement of a virtual intra-medullary pin. A proximal osteotomy was simulated to create three conditions while keeping torsion constant: Normal, Coxa Valga (neck-shaft angle increased by 12°), and Coxa Vara (neck-shaft angle decreased by 12°). Femoral anteversion was measured from an axial image in all three conditions. Femoral inclination was calculated for all conditions using the neck-shaft and anteversion angles. Changes in anteversion and inclination were calculated and compared using a one-way repeated measures analysis of variance. Distal femoral osteotomies were then simulated with the native femurs, inducing 18° of distal varus with no change to torsion. Changes in anteversion and inclination for the Normal and Distal Varus conditions were calculated and compared by a paired t-test. Results: Version changed by a mean of 13.9° (± 1.5; p <0.0001) from the Coxa Valga to Coxa Vara conditions while inclination changed by a mean of 1.3° (± 0.39; p <0.01). Version changed by a mean of 6.6° (± 0.7; p <0.0001) between the Distal Varus and Normal conditions while inclination changed by a mean of –3.8° (± 0.75; p <0.001). Clinical significance: Femoral version changes with changing frontal plane alignment even when torsion is constant. This should be considered when correcting femoral deformities.

scholarly journals Three-dimensional Analysis of Lip Changes in Response To Simulated Maxillary Incisor Advancement

2019 ◽  
Vol 90 (1) ◽  
pp. 118-124
Author(s):  
Joanne Au ◽  
Li Mei ◽  
Florence Bennani ◽  
Austin Kang ◽  
Mauro Farella
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Interindividual Variation ◽  
Maxillary Incisor ◽  
Anatomical Landmarks ◽  
Repeated Measures Analysis ◽  
3D Stereophotogrammetry ◽  
Study Participants

ABSTRACT Objective To assess the immediate response of lips in three dimensions (3D) resulting from simulated maxillary incisor advancement. Materials and Methods Incremental maxillary incisor advancement was simulated by placing wax of increasing thickness (+2 mm, +4 mm, +6 mm) on the incisors of 20 participants, and the induced lip changes were recorded using 3D stereophotogrammetry. The induced displacement of lip landmarks was quantified using 3D image analysis software. Data were analyzed using a repeated-measures analysis of variance (ANOVA) after adjusting for age and sex of the study participants. Results A large interindividual variation in lip response to simulated incisor advancement was observed. A significant overall effect on 3D lip changes was found for increasing values of simulated incisor advancement (F = 13.2; P &lt; .001) as well as significant differences between anatomical landmarks of the lip (F = 7.4; P &lt; .01). Most points moved outward and anterosuperiorly, except the midpoint and corners of the lip. Greatest movement was observed in the sagittal plane, followed by the vertical and transverse planes. Conclusions Maxillary incisor advancement significantly affects upper lip change in three planes of space: particularly the anteroposterior plane, in which the response to simulated advancement appears to be nonlinear.

scholarly journals Cytocompatibility of 3D printed dental materials for temporary restorations on fibroblasts

2020 ◽  
Author(s):  
Jung-Hyun Park ◽  
Hyun Lee ◽  
Jong-Woo Kim ◽  
Ji-Hwan Kim
Keyword(s):  
Cell Proliferation ◽  
Cell Adhesion ◽  
3D Printing ◽  
Laser Scanning ◽  
Dental Materials ◽  
Confocal Laser ◽  
Control Group ◽  
Digital Light Processing ◽  
3D Printed ◽  
Materials Used

Abstract Background Three-dimensional (3D) printing is widely used in the fabrication of dental prostheses; however, the influence of dental materials used for 3D printing on temporary restoration of fibroblasts in tissues is unclear. Thus, the influence of different dental materials on fibroblasts were investigated. Methods Digital light processing (DLP) type 3D printing was used. Specimens in the control group were fabricated by mixing liquid and powder self-curing resin restoration materials. The temporary resin materials used were Model, Castable, Clear-SG, Tray, and Temporary, and the self-curing resin materials used were Lang dental, Alike, Milky blue, TOKVSO CUREFAST, and UniFast III. Fibroblast cells were cultured on each specimen and subsequently post-treated for analysis. Morphology of the adhered cells were observed using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM). Results CLSM and SEM cell imaging revealed that the 3D printed material group presented better cell adhesion with well-distributed filopodia compared to that in the conventional resin material group. Cell proliferation was significantly higher in the 3D printing materials. Conclusion Superior cytocompatibility of the specimens fabricated through 3D printing and polishing process was demonstrated with the proof of better cell adhesion and higher cell proliferation.

scholarly journals Cytocompatibility of 3D printed dental materials for temporary restorations on fibroblasts

2020 ◽  
Author(s):  
Jung-Hyun Park ◽  
Hyun Lee ◽  
Jong-Woo Kim ◽  
Ji-Hwan Kim
Keyword(s):  
Cell Proliferation ◽  
Cell Adhesion ◽  
3D Printing ◽  
Laser Scanning ◽  
Dental Materials ◽  
Confocal Laser ◽  
Control Group ◽  
Digital Light Processing ◽  
3D Printed ◽  
Materials Used

Abstract Background Three-dimensional (3D) printing is widely used in the fabrication of dental prostheses; however, the influence of dental materials used for 3D printing on temporary restoration of fibroblasts in tissues is unclear. Thus, the influence of different dental materials on fibroblasts were investigated. Methods Digital light processing (DLP) type 3D printing was used. Specimens in the control group were fabricated by mixing liquid and powder self-curing resin restoration materials. The temporary resin materials used were Model, Castable, Clear-SG, Tray, and Temporary, and the self-curing resin materials used were Lang dental, Alike, Milky blue, TOKVSO CUREFAST, and UniFast III. Fibroblast cells were cultured on each specimen and subsequently post-treated for analysis. Morphology of the adhered cells were observed using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM). Results CLSM and SEM cell imaging revealed that the 3D printed material group presented better cell adhesion with well-distributed filopodia compared to that in the conventional resin material group. Cell proliferation was significantly higher in the 3D printing materials. Conclusion Superior cytocompatibility of the specimens fabricated through 3D printing and polishing process was demonstrated with the proof of better cell adhesion and higher cell proliferation.

scholarly journals Kinetic Sensitivity of a New Lumbo-Pelvic Model to Variation in Segment Parameter Input

2013 ◽  
Vol 29 (3) ◽  
pp. 354-359 ◽  
Author(s):  
Helen Crewe ◽  
Amity Campbell ◽  
Bruce Elliott ◽  
Jacqueline Alderson
Keyword(s):  
Repeated Measures ◽  
Three Dimensional ◽  
Analysis Data ◽  
Data Sets ◽  
Anatomical Landmarks ◽  
Vertebral Level ◽  
Repeated Measures Analysis ◽  
Final Approach ◽  
Segmentation Approach ◽  
Body Segment Parameters

This study aimed to assess variability in lumbo-pelvic forces and moments during a dynamic high-impact activity (cricket fast bowling) when calculated using different body segment parameters (BSPs). The first three BSPs were estimated using methods where the trunk was divided into segments according to nonspinal anatomical landmarks. The final approach defined segment boundaries according to vertebral level. Three-dimensional motion analysis data from nine male cricketers’ bowling trials were processed using the four BSPs. A repeated-measures analysis of variance revealed no significant effect on peak lumbo-pelvic forces. However, the segmentation approach based on vertebral level resulted in significantly larger peak flexion and lateral flexion moments than the other BSP data sets. This has implications for comparisons between studies using different BSPs. Further, given that a method defined with reference to vertebral level more closely corresponds with relevant anatomical structures, this approach may more accurately reflect lumbar moments.

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