scholarly journals Challenging the Resin-Zirconia Interface by Thermal Cycling or Mechanical Load Cycling or Their Combinations

2020 ◽  
Vol 10 (20) ◽  
pp. 7352
Author(s):  
Sung-Min Kwon ◽  
Young Kyung Kim ◽  
Tae-Yub Kwon
Keyword(s):  
Thermal Cycling ◽  
Mechanical Load ◽  
In Vitro Study ◽  
Resin Cements ◽  
Mechanical And Physical Properties ◽  
Load Cycling ◽  
Bonding Area ◽  
Before And After ◽  
Aging Conditions

The purpose of this in vitro study was to evaluate the influence of mechanical load cycling (MLC), which simulated mastication, alone or combined with thermal cycling (TC), on the resin shear bond strength (SBS) to zirconia. Two resin cements (Panavia F2.0 and RelyX U200) were bonded (bonding area: 2.38 mm) to air-abraded zirconia (Everest ZS-Ronde). The specimens were subjected to SBS test before and after TC (5000 cycles), MLC (5000 cycles in 37 °C water), TC/MLC, or MLC/TC aging (n = 15). Before SBS test, the mechanical and physical properties of the two resin cements were studied (n = 5). For both resins, unlike TC (p > 0.05), the three MLC-containing aging conditions significantly decreased the SBS values when compared to the non-aged condition (p < 0.05). In the case of MLC-only aging, RelyX U200, with significantly higher hydrophobicity (p = 0.004), showed a significantly higher SBS value than Panavia F2.0 (p = 0.035). The MLC aging-containing groups showed increased occurrence of mixed failure. The application of MLC combined with TC may more closely simulate intraoral conditions.

scholarly journals Effect of Thermo-mechanical Load Cycling on Microleakage in Class II Ormocer Restorations

2009 ◽  
Vol 03 (03) ◽  
pp. 200-206 ◽  
Author(s):  
Dina Erdilek ◽  
Can Dörter ◽  
Fatma Koray ◽  
Karl-Heinz Kunzelmann ◽  
Begum Guray Efes ◽  
...  
Keyword(s):  
Hybrid Composite ◽  
Mechanical Load ◽  
In Vitro Study ◽  
Clinical Problem ◽  
Class Ii ◽  
Dye Penetration ◽  
Load Cycling ◽  
In Vitro Assessment ◽  
Distal Direction

ABSTRACTObjectives: The objective of this in vitro study was to evaluate the marginal sealing ability of an ormocer in comparison with a hybrid composite when using thermocycling and load cycling procedures together in the study design.Methods: Modified proximal Class II cavities were prepared on the mesial and distal surfaces of twenty-two human premolars. Each tooth was restored with Admira and contralaterally with TPH Spectrum. Half of all of the teeth were subjected to thermo-mechanical load cycling. After dye penetration, longitudinal sections in mesio-distal direction were prepared and examined under a stereomicroscope. Data were analyzed with Mann Whitney U test.Results: The results showed that the thermo-mechanical load cycling caused a statistically significant increase in gingival microleakage when compared with the non-thermocycled and nonloaded restorations for both the materials Admira (P=0.006) and TPH Spectrum (P=0.023).Conclusions: Simultaneous load cycling and thermocycling are decisive factors in the in vitro assessment of gingival microleakage, which still remains to be a clinical problem even with the ormocer system Admira. (Eur J Dent 2009;3:200-206)

Histologic evidence that mast cells contribute to local tissue inflammation in peripheral spondyloarthritis by regulating interleukin-17A content

Rheumatology ◽  
2018 ◽  
Vol 58 (4) ◽  
pp. 617-627 ◽  
Author(s):  
Sijia Chen ◽  
Troy Noordenbos ◽  
Iris Blijdorp ◽  
Leonieke van Mens ◽  
Carmen A Ambarus ◽  
...  
Keyword(s):  
Mast Cells ◽  
Synovial Tissue ◽  
In Vitro Study ◽  
Allergic Diseases ◽  
Psoriatic Skin ◽  
Tissue Inflammation ◽  
Interleukin 17A ◽  
Before And After ◽  
Peripheral Spondyloarthritis

Abstract Objectives Synovial mast cells contain IL-17A, a key driver of tissue inflammation in SpA. A recent in vitro study showed that tissue-derived mast cells can capture and release exogenous IL-17A. The present study aimed to investigate if this mechanism could contribute to tissue inflammation in SpA. Methods Potential activation of mast cells by IL-17A was assessed by gene expression analysis of the Laboratory of Allergic Diseases 2 (LAD2) mast cell line. The presence of IL-17A-positive mast cells was assessed by immunohistochemistry in synovial tissue obtained before and after secukinumab treatment, as well as in skin and gut tissues from SpA-related conditions. Results IL-17A did not induce a pro-inflammatory response in human LAD2 mast cells according to the canonical IL-17A signalling pathway. In SpA synovial tissue, the percentage of IL-17A-positive mast cells increased upon treatment with secukinumab. IL-17A-positive mast cells were also readily detectable in non-inflamed barrier tissues such as skin and gut. In non-inflamed dermis and gut submucosa, IL-17A-positive mast cells are the most prevalent IL-17A-positive cells in situ. Compared with non-inflamed tissues, both total mast cells and IL-17A-positive mast cells were increased in psoriatic skin dermis and in submucosa from inflammatory bowel disease gut. In contrast, the proportion of IL-17A-positive mast cells was strikingly lower in the inflamed compared with non-inflamed gut lamina propria. Conclusion IL-17A-positive mast cells are present across SpA target tissues and correlate inversely with inflammation, indicating that their IL-17A content can be regulated. Tissue-resident mast cells may act as IL-17A-loaded sentinel cells, which release IL-17A to amplify tissue inflammation.

Comparison of bivalirudin, enoxaparin, and unfractionated heparin in preventing cardiac catheter thrombosis

2008 ◽  
Vol 100 (10) ◽  
pp. 693-698 ◽  
Author(s):  
Michael Buerke ◽  
Sebastian Schubert ◽  
Iris Reindl ◽  
Thomas Michel ◽  
Baerbel Hauroeder ◽  
...  
Keyword(s):  
Unfractionated Heparin ◽  
Continuous Infusion ◽  
Treatment Strategies ◽  
In Vitro Study ◽  
Coronary Intervention ◽  
Thrombin Inhibitor ◽  
P Value ◽  
Cardiac Catheter ◽  
Before And After

SummaryBivalirudin, a direct thrombin inhibitor binds specifically and reversibly to both fibrin-bound and unbound thrombin. Bivalirudin is approved for use as an anticoagulant in patients undergoing percutaneous coronary intervention. The OASIS-5 trial presented a significant increase in cardiac catheter thrombosis for the pentasaccharid fondaparinux compared to enoxaparin. Catheter thrombosis has never been reported in any trial using bivalirudin. Our study compared the development of catheter thrombosis for bivalirudin, enoxaparin, and unfractionated heparin in a controlled in-vitro environment. Ten healthy male volunteers were pretreated with aspirin 500 mg 2 hours before venesection of 50 ml of blood. The seven groups of anticoagulant combinations tested were:UFH, UFH + eptifibatide, enoxaparin, enoxaparin + eptifibatide, bivalirudin bolus, bivalirudin + eptifibatide, bivalirudin bolus + continuous infusion. The blood/anticoagulant mix continuously circulated through a cardiac guiding catheter for 60 minutes or until the catheter became blocked with thrombus. Thrombus development was assessed by weighing each catheter before and after the procedure. Electron microscopy was used to quantify the degree of erythrocyte, platelet and fibrin deposition. Following anticoagulation with bolus dose bivalirudin, the catheter was invariably occluded with thrombus after 33 minutes of circulation. However, a continuous infusion of Bivalirudin prevented the development of occlusive catheter thrombosis. In the bolus bivalirudin group the mean thrombus weight was significantly greater than in all other groups (p-value < 0.01 in all analyses). Bivalirudin given as a bolus was not sufficient to prevent cardiac catheter thrombosis in our in-vitro study. However, a continuous infusion of bivalirudin had similar anti-thrombotic efficacy compared to other treatment strategies.

scholarly journals Comparison of the Remineralizing Effect of Brushing with Aloe vera versus Fluoride Toothpaste

2020 ◽  
Author(s):  
Teresa Al Haddad ◽  
Elie Khoury ◽  
Nada Farhat Mchayleh
Keyword(s):  
Repeated Measures ◽  
Aloe Vera ◽  
In Vitro Study ◽  
P Value ◽  
Fluoride Toothpaste ◽  
Before And After ◽  
The Difference ◽  
Group B ◽  
Ca:P Ratio

Abstract Objectives The aim of the present in vitro study is to compare the remineralization brushing effect of three toothpastes and Aloe vera (AV) gel. Materials and Methods Forty sound extracted teeth were placed in a demineralizing solution for 4 days and randomly assigned to four groups: group A: 1,450-ppm fluoride toothpaste; group B: AV nonfluoridated toothpaste; group C: AV 1,000-ppm fluoridated toothpaste; and group D: AV gel. A 3-minute pH cycling was performed twice a day for each group for 12 days. Specimens were analyzed before and after by scanning electron microscope—energy dispersive X-ray. Statistical analysis The outcomes were analyzed by Kolmogorov–Smirnov’s tests, repeated-measures analyses of variance followed by univariate analyses, and Bonferroni’s multiple comparisons tests to compare the calcium-to-phosphorus (Ca:P) ratio within time among toothpaste groups. Results Following remineralization, the Ca:P ratio increased in all groups. The difference of the Ca:P ratio was not significant between groups C, D, and A. The mean ratio was significantly lower in group B (p-value = 0.026). Conclusions The AV gel demonstrated a remineralization capacity equal to that of the 1,450-ppm fluoride toothpaste. In contrast, fluoride-free AV toothpaste showed a lower remineralization efficiency. Further studies are required to understand its mechanism.

scholarly journals Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1853 ◽  
Author(s):  
Ella Naumova ◽  
Felix Roth ◽  
Berit Geis ◽  
Christine Baulig ◽  
Wolfgang Arnold ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Storage Conditions ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Cobalt Chromium ◽  
Retention Force ◽  
Implant Abutments ◽  
Aging Conditions

The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt–chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (−773 N), whereas RelyX TempBond NE had the lowest (−146 N). After aging (S2), Meron had the highest retention force median value difference (−783 N), whereas RelyX TempBond NE had the lowest (−168 N). Recementation decreased the retention force of the implant-supported cobalt–chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.

Demineralization Inhibitory Effects of Highly Concentrated Fluoride Dentifrice and Fluoride Gels/Solutions on Sound Dentin and Artificial Dentin Caries Lesions in vitro

2020 ◽  
pp. 1-14
Author(s):  
Daniel Erdwey ◽  
Hendrik Meyer-Lueckel ◽  
Marcella Esteves-Oliveira ◽  
Christian Apel ◽  
Richard Johannes Wierichs
Keyword(s):  
In Vitro Study ◽  
Inhibitory Effect ◽  
Negative Effects ◽  
Dentin Caries ◽  
Before And After ◽  
Amine Fluoride ◽  
Ph Cycling ◽  
Fluoride Dentifrice ◽  
Caries Lesions

<b><i>Objectives:</i></b> The aim of this in vitro study was to compare the demineralization inhibitory effect of gels/solutions used in combination with either standard or highly fluoridated dentifrices on sound dentin as well as on artificial dentin caries-like lesions. <b><i>Methods:</i></b> Bovine dentin specimens (<i>n</i> = 240) with two different surfaces each (sound [ST] and artificial caries lesion [DT]) were prepared and randomly allocated to twelve groups. Weekly interventions during pH-cycling (28 days, 6 × 120 min demineralization/day) were: the application of gels/solutions containing amine fluoride/sodium fluoride (12,500 ppm F [ppm]; pH = 4.4; AmF); NaF (12,500 ppm; pH = 6.6; NaF1); NaF (12,500 ppm; pH = 6.3; NaF2); silver diamine fluoride (14,200 ppm; pH = 8.7; SDF); acidulated phosphate fluoride (12,500 ppm; pH = 3.8; APF), and no intervention (standard control; S). Furthermore, half of the specimens in each group were brushed (10 s; twice per day) with dentifrice slurries containing either 1,450 ppm (e.g., AmF<sub>1450</sub>) or 5,000 ppm (e.g., AmF<sub>5000</sub>). Differences in integrated mineral loss (ΔΔZ) and lesion depth (ΔLD) were calculated between values before and after pH-cycling using transversal microradiography. <b><i>Results:</i></b> After pH-cycling Ss showed significantly increased ΔZ<sub>DT</sub> and LD<sub>DT</sub> values, indicating further demineralization. In contrast, except for one, all groups including fluoride gels/solutions showed significantly decreased ΔZ<sub>DT</sub> values. Additional use of most fluoride gels/solutions significantly enhanced mineral gain, mainly in the surface area; however, acidic gels/solutions seemed to have negative effects on lesion depths. <b><i>Significance:</i></b> Under the present pH-cycling conditions the highly fluoridated dentifrice significantly reduced caries progression and additional application of nearly all of the fluoride gels/solutions resulted in remineralization. However, there was no difference in the remineralizing capacity of fluoride gels/solutions when used in combination with either standard or highly fluoridated dentifrices.

scholarly journals Deformation of the Internal Connection of Narrow Implants after Insertion in Dense Bone: An in Vitro Study

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1833 ◽  
Author(s):  
Rafael Delgado-Ruiz ◽  
Ana Nicolas Silvente ◽  
Georgios Romanos
Keyword(s):  
In Vitro Study ◽  
Surface Damage ◽  
Insertion Torque ◽  
Type Ii ◽  
Before And After ◽  
Post Test ◽  
Group A ◽  
Group B ◽  
Connection Length

Implant connections must resist surgical and prosthetic procedures without deformation. This study evaluated the deformation of different internal connections (IC) of narrow dental implants (NDI) after their insertion in artificial dense bone. Thirty NDI, with different IC geometries, Group A (internal hexagon), Group B (tri-channeled), and Group C (four-channeled), with the same length and similar narrow diameters, were inserted in type II density bone blocks. Drilling protocols for dense bone from each implant manufacturer were followed. The Insertion torque (IT), connection length, vertex angles, and wall deformations were analyzed before and after the insertion of the implants. ANOVA (Analysis of Variance) and Tukey post-test were used for statistical comparisons. IT values were higher for Group A, surface damage, and titanium particles were observed in the IC in all the groups. Angle deformations between 5 and 70 degrees were present in all the groups, and the walls of Group B connection were the most affected by deformations (p < 0.05). Within the limitations of this experiment, it can be concluded that narrow diameter implants will suffer deformation of the implant connection and will also experience surface damage and titanium particle release when inserted in type II bone density.

scholarly journals Single blinded in-vitro study comparing microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramic, cemented with three resin cements

2019 ◽  
Vol 18 (4) ◽  
pp. 764-772
Author(s):  
Asa Yazdani Fard ◽  
Zuryati Ab Ghani ◽  
Zaihan Ariffin ◽  
Dasmawati Mohamad
Keyword(s):  
Computer Aided Design ◽  
Medical Science ◽  
In Vitro Study ◽  
Resin Cement ◽  
Blue Dye ◽  
Resin Cements ◽  
Etch And Rinse ◽  
Computer Aided ◽  
Cad Cam

Background: Studies on microleakage of Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) crowns are abundant. However many of them are inconclusive, especially those using self adhesive cements. Aims: To compare the microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramics, cemented with three resin cements. Materials and Methods: Crown preparation was made on 54 extracted human premolars. Impressions were captured optically using CEREC 3D machine intraoral camera, and crowns were milled from feldspathic ceramic (CEREC® Blocs PC, VITA) and resin nano ceramic (Lava™ Ultimate CAD/CAM Restorative, 3M ESPE) blocks. The crowns were then cemented with three cements (n = 9); RelyX™ U200 Self-Adhesive Resin Cement (3M ESPE); NX3 Nexus ® cement with two-step etch-and-rinse adhesive (Kerr Corporation) or three/multistep etch-and-rinse resin cement, Variolink® II/Syntac Classic (Ivoclar Vivadent). The specimens were kept in water for 24 hours, thermocycled, and then soaked in methylene blue dye for 24 hours, before being sectioned mesiodistally. Microleakage was assessed using a fivepoint scale using stereomicroscope. Statistical analysis of the data was carried out using ONEWay ANOVA. Results: CEREC® Blocs PC crowns showed significantly less microleakage (p< 0.001) compared to Lava™ Ultimate. RelyX™ U200 showed significantly lower microleakage (p< 0.001) compared to other cements. Combination of Lava™ Ultimate crown cemented with RelyX™ U200 showed the least microleakage (p< 0.001). Conclusions: The microleakage scores were affected by the types of crown and cements. Bangladesh Journal of Medical Science Vol.18(4) 2019 p.764-772

scholarly journals In Vitro Study on the Effect of a New Bioactive Desensitizer on Dentin Tubule Sealing and Bonding

2020 ◽  
Vol 11 (2) ◽  
pp. 38
Author(s):  
Minh N. Luong ◽  
Laurie Huang ◽  
Daniel C. N. Chan ◽  
Alireza Sadr
Keyword(s):  
Bond Strength ◽  
In Vitro Study ◽  
Vitro Study ◽  
Acid Pretreatment ◽  
Universal Adhesive ◽  
Cross Sectional ◽  
Before And After ◽  
Human Dentin ◽  
Microshear Bond Strength

Bioactive mineral-based dentin desensitizers that can quickly and effectively seal dentinal tubules and promote dentin mineralization are desired. This in vitro study evaluated a novel nanohydroxyapatite-based desensitizer, Predicta (PBD, Parkell), and its effect on bond strength of dental adhesives. Human dentin discs (2-mm thick) were subjected to 0.5 M EDTA to remove the smear layer and expose tubules, treated with PBD, and processed for surface and cross-sectional SEM examination before and after immersion in simulated body fluid (SBF) for four weeks (ISO 23317-2014). The effects of two dental desensitizers on the microshear bond strength of a universal adhesive and a two-step self-etch system were compared. SEM showed coverage and penetration of nanoparticles in wide tubules on the PBD-treated dentin at the baseline. After four weeks in SBF, untreated dentin showed amorphous mineral deposits while PBD-treated dentin disclosed a highly mineralized structure integrated with dentin. Desensitizers significantly reduced microshear bond strength test (MSBS) of adhesives by 15–20% on average, depending on the bonding protocol. In conclusion, PBD demonstrated effective immediate tubules sealing capability and promoted mineral crystal growth over dentin and into the tubules during SBF-storage. For bonding to desensitizer-treated dentin, a two-step self-etching adhesive or universal bond with phosphoric acid pretreatment are recommended.

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