scholarly journals Retention Forces of Prosthetic Clasps over a Simulated Wearing Period of Six Years In-Vitro: Direct Metal Laser Melting Versus Dental Casting

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5339
Author(s):  
Moritz Mutschler ◽  
Florian Schweitzer ◽  
Sebastian Spintzyk ◽  
Jürgen Geis-Gerstorfer ◽  
Fabian Huettig
Keyword(s):  
Clinical Relevance ◽  
Fatigue Behavior ◽  
Molar Tooth ◽  
Tooth Crown ◽  
Laser Melting ◽  
Dental Casting ◽  
Retention Force ◽  
Computer Aided ◽  
Dental Application

This study determinates the persistence of retention force in Akers-clasps for removable partial dentures made from Co-Cr alloy. Therefore, standardized computer-aided designed (CAD) clasp #1 specimens were made by direct metal laser melting (DMLM, n = 10) and by lost-wax dental casting (DC) of computer-aided manufactured (CAM) replicas (n = 10, DC) from two comparable Co-Cr alloys. The retention force was tested after manufacturing for 9000 cycles of setting and removal from a molar tooth crown analog made from zirconia; simulating in-vitro a duration of six years in service. The first and last 360 cycles (T0 and T1, 3 months each) of all specimens were selected for comparison of retention forces between the materials. A constant decrease of 6% from the initial retention force (T0 = 4.86 N, SD = 0.077; T1 = 4.57 N, SD = 0.037) was detected at the DC specimens, and an increase of 4% in DMLM specimens (T0 = 5.69 N, SD = 0.078; T1 = 5.92 N, SD = 0.077); all differences were statistically significant (p < 0.0001). Even if these deviations are not of clinical relevance, further studies and applications should investigate the fatigue behavior of laser melted Co-Cr-alloys for dental application.

scholarly journals Parameters Affecting the Retention Force of CAD/CAM Telescopic Crowns: A Focused Review of In Vitro Studies

2021 ◽  
Vol 10 (19) ◽  
pp. 4429
Author(s):  
Abdullah Kamel ◽  
Amr Badr ◽  
Gehan Fekry ◽  
James Tsoi
Keyword(s):  
Scoping Review ◽  
Computer Aided Design ◽  
In Vitro Studies ◽  
Eligibility Criteria ◽  
Retention Force ◽  
Electronic Search ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

Telescopic systems constructed using computer aided design and computer aided manufacture (CAD/CAM) can overcome many drawbacks associated with conventionally constructed ones. Since retention is considered the most important function of these retainers, this scoping review aimed to discuss and summarize the parameters that affect this function in CAD/CAM-manufactured telescopic crowns and to compare their retention force values with the recommended retention force. An electronic search was done in Pubmed and Google Scholar databases using different keyword combinations to find the related articles. Seventeen articles that follow the eligibility criteria for this review were selected and analyzed for detection of each of the tested parameters and their effect on retention force. The parameters tested in these articles were divided into parameters related to design, manufacturing, material type, and test condition. Regardless of the effect of these parameters, the retention force values recorded in most of the selected studies laid within or were higher than the recommended retention force (2.5–10 N), which indicated the need to design and set the combination of materials of telescopic systems according to oral biomechanics.

scholarly journals Homozygous MTAP deletion in primary human glioblastoma is not associated with elevation of methylthioadenosine

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yasaman Barekatain ◽  
Jeffrey J. Ackroyd ◽  
Victoria C. Yan ◽  
Sunada Khadka ◽  
Lin Wang ◽  
...  
Keyword(s):  
Clinical Relevance ◽  
Homozygous Deletion ◽  
In Vitro Models ◽  
Arginine Methyltransferase ◽  
Human Glioblastoma ◽  
Primary Glioblastoma ◽  
Methylthioadenosine Phosphorylase ◽  
Metabolomic Profiling

AbstractHomozygous deletion of methylthioadenosine phosphorylase (MTAP) in cancers such as glioblastoma represents a potentially targetable vulnerability. Homozygous MTAP-deleted cell lines in culture show elevation of MTAP’s substrate metabolite, methylthioadenosine (MTA). High levels of MTA inhibit protein arginine methyltransferase 5 (PRMT5), which sensitizes MTAP-deleted cells to PRMT5 and methionine adenosyltransferase 2A (MAT2A) inhibition. While this concept has been extensively corroborated in vitro, the clinical relevance relies on exhibiting significant MTA accumulation in human glioblastoma. In this work, using comprehensive metabolomic profiling, we show that MTA secreted by MTAP-deleted cells in vitro results in high levels of extracellular MTA. We further demonstrate that homozygous MTAP-deleted primary glioblastoma tumors do not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma. These findings highlight metabolic discrepancies between in vitro models and primary human tumors that must be considered when developing strategies for precision therapies targeting glioblastoma with homozygous MTAP deletion.

scholarly journals Comparison of Proximal Contacts of Class II Resin Composite Restorations In Vitro

2006 ◽  
Vol 31 (6) ◽  
pp. 688-693 ◽  
Author(s):  
B. A. C. Loomans ◽  
N. J. M. Opdam ◽  
F. J. M. Roeters ◽  
E. M. Bronkhorst ◽  
R. C. W. Burgersdijk
Keyword(s):  
Clinical Relevance ◽  
Resin Composite ◽  
Class Ii ◽  
Composite Restorations ◽  
Composite Restoration

Clinical Relevance When placing a Class II resin composite restoration, the use of sectional matrix systems and separation rings to obtain tight proximal contacts is recommended.

Comparison of Temperature Changes in the Pulp Chamber Induced by Various Light Curing Units, In Vitro

10.2341/05-26 ◽  
2006 ◽  
Vol 31 (2) ◽  
pp. 261-265 ◽  
Author(s):  
A. R. Yazici ◽  
A. Müftü ◽  
G. Kugel ◽  
R. D. Perry
Keyword(s):  
Clinical Relevance ◽  
Critical Factor ◽  
Pulp Chamber ◽  
Temperature Changes ◽  
Thermal Transfer ◽  
Light Curing

Clinical Relevance The thickness of the residual dentin is a critical factor in the reducing thermal transfer to pulp, and this transfer varies with the curing unit used.

scholarly journals The Influence of Exposure Energy Density on Porosity and Microhardness of the SLM Additive Manufactured Elements

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2304 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Krzysztof Grzelak ◽  
Janusz Mierzyński
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Final Analysis ◽  
Machine Building ◽  
Layer By Layer ◽  
Laser Melting ◽  
Measurement Results ◽  
Computer Aided ◽  
Exposure Energy ◽  
Aided Design

Selective laser melting (SLM) is an additive manufacturing technique. It allows elements with very complex geometry to be produced using metallic powders. A geometry of manufacturing elements is based only on 3D computer-aided design (CAD) data. The metal powder is melted selectively layer by layer using an ytterbium laser. This paper contains the results of porosity and microhardness analysis made on specimens manufactured during a specially prepared process. Final analysis helped to discover connections between changing hatching distance, exposure speed and porosity. There were no significant differences in microhardness and porosity measurement results in the planes perpendicular and parallel to the machine building platform surface.

Marginal, Internal Fit and Microleakage of Zirconia Infrastructures: An In-Vitro Study

2011 ◽  
Vol 36 (1) ◽  
pp. 72-79 ◽  
Author(s):  
L. Korkut ◽  
H. S. Cotert ◽  
H. Kurtulmus
Keyword(s):  
Clinical Relevance ◽  
In Vitro Study ◽  
Manufacturing Technology ◽  
Vitro Study ◽  
Internal Fit ◽  
Fitting Accuracy

Clinical Relevance Fitting accuracy and microleakage dominate prognostic covariates for the long-term durability of crown restorations. The fitting accuracy and microleakage potential of zirconia infrastructures might be influenced by manufacturing technology.

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