scholarly journals Influence of descending height of standardized antagonist for the in-vitro wear resistance of dental composite materials

2019 ◽  
Vol 6 (1) ◽  
pp. 955-961
Author(s):  
Ivan Chakalov ◽  
Pavlina Koleva ◽  
Ivan Gerzhikov ◽  
Nickolay Apostolov
2018 ◽  
Vol 25 (4) ◽  
pp. 781-787 ◽  
Author(s):  
Efe Cetin Yılmaz ◽  
Recep Sadeler

Abstract This paper investigates the three-body wear resistance rates of five restorative dental composite materials at different mastication cycles and compares the results with that of an amalgam material. Five specimens of each material were exposed three-body wear tests using a computer-controlled chewing simulator with steatite balls as the antagonist (1.6 Hz, 49 N load; 120,000, 240,000 and 480,000 mechanical cycles; and thermal cycling between 5 and 55°C at 5 min/cycle and 3000 cycles) immersed in a poppy seed slurry (three-body wear environment). Initially, the microhardness values of the composite materials in the Vicker’s hardness (HV) scale were determined. The mean volume loss of the worn surfaces was measured with a three-dimensional profilometer. Means and standard deviations were calculated, and statistical analysis was performed using one-way ANOVA (α=0.05). Additionally, scanning electron microscopy analysis was performed to examine the wear tracks on the surface. The interactions between the composite resin and mean volume loss were found to be significant. The three-body wear rates for the composites Durafil and Kalore composite were significantly higher than those of the other composites and the amalgam irrespective of the number of mastication cycles. Filtek Z250 and Filtek Supreme composite resins had good three-body wear resistance similar to that of the amalgam. However, this study suggests that the correlation between Vicker’s hardness and three-body wear resistance is not significant.


Author(s):  
David J. Bradshaw ◽  
James T. Walker ◽  
Bernd Burger ◽  
Bernd Gangnus ◽  
Phil D. Marsh

Author(s):  
Markéta Šimková ◽  
Antonín Tichý ◽  
Michaela Dušková ◽  
Jana Vítků ◽  
Lucie Kolatorova ◽  
...  

2019 ◽  
Vol 56 (3) ◽  
pp. 529-533
Author(s):  
Mihaela Pantea ◽  
Diana Andreea Ighigeanu ◽  
Alexandra Totan ◽  
Maria Greabu ◽  
Daniela Miricescu ◽  
...  

This in vitro study analyses the biochemical interaction between saliva and three types of dental composite resins (a direct resin, an indirect resin and a dual-cure resin used for cementation of indirect dental restorations). The resin samples were obtained following a specific protocol and in line with the producers� recommendations; the resin samples were incubated with saliva samples collected from 19 healthy volunteers. The obtained results showed that the tested composite resins did not produce significant changes in oxidative stress parameters that were analysed (albumin, uric acid, GGT / gamma glutamyl transferase, OXSR-1 / oxidative stress responsive kinase 1) and do not influence the inflammatory salivary status reflected by the levels of IL-6 - an inflammatory marker.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 567
Author(s):  
Anun Wongpayakyotin ◽  
Chanchira Jubsilp ◽  
Sunan Tiptipakorn ◽  
Phattarin Mora ◽  
Christopher W. Bielawski ◽  
...  

A series of substituted polybenzoxazines was synthesized and studied as binders in non-asbestos friction composite materials. The structures of the polybenzoxazines were varied in a systemic fashion by increasing the number and position of pendant alkyl (methyl) groups and was accomplished using the respective aromatic amines during the polymer synthesis step. By investigating the key thermomechanical and tribological characteristics displayed by the composite materials, the underlying structure-properties relationships were deconvoluted. Composite friction materials with higher thermomechanical and wear resistance properties were obtained from polybenzoxazines with relatively high crosslink densities. In contrast, polybenzoxazines with relatively low crosslink densities afforded composite friction materials with an improved coefficient of friction values and specific wear rates.


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 470
Author(s):  
Andrea Kowalska ◽  
Jerzy Sokolowski ◽  
Kinga Bociong

The presented paper concerns current knowledge of commercial and alternative photoinitiator systems used in dentistry. It discusses alternative and commercial photoinitiators and focuses on mechanisms of polymerization process, in vitro measurement methods and factors influencing the degree of conversion and hardness of dental resins. PubMed, Academia.edu, Google Scholar, Elsevier, ResearchGate and Mendeley, analysis from 1985 to 2020 were searched electronically with appropriate keywords. Over 60 articles were chosen based on relevance to this review. Dental light-cured composites are the most common filling used in dentistry, but every photoinitiator system requires proper light-curing system with suitable spectrum of light. Alternation of photoinitiator might cause changing the values of biomechanical properties such as: degree of conversion, hardness, biocompatibility. This review contains comparison of biomechanical properties of dental composites including different photosensitizers among other: camphorquinone, phenanthrenequinone, benzophenone and 1-phenyl-1,2 propanedione, trimethylbenzoyl-diphenylphosphine oxide, benzoyl peroxide. The major aim of this article was to point out alternative photoinitiators which would compensate the disadvantages of camphorquinone such as: yellow staining or poor biocompatibility and also would have mechanical properties as satisfactory as camphorquinone. Research showed there is not an adequate photoinitiator which can be as sufficient as camphorquinone (CQ), but alternative photosensitizers like: benzoyl germanium or novel acylphosphine oxide photoinitiators used synergistically with CQ are able to improve aesthetic properties and degree of conversion of dental resin.


2014 ◽  
Vol 60 (5) ◽  
pp. 200-203
Author(s):  
Andreea Borş ◽  
Cristina Molnar-Varlam ◽  
Melinda Székely

Abstract Objective: The aim of this in vitro study was to evaluate the influence of erosive conditions on the wear resistance of aesthetic direct restorative materials. Methods: Six dental filling materials were tested: two composites (Filtek Z550 and X-tra fil), two compomers (Dyract Extra and Twinky Star) and two glass ionomers (Ketac Molar and Fuji II LC). Twenty disks (10mm×2mm) of each material were prepared (n=120) and kept in artificial saliva at 37˚C for 24 hours. Specimens were cycled in acidic soft drink (Coca-Cola) 5×/day, for 5’, over 30 days. Initial surface roughness ISR (Ra-μm) and final surface roughness FSR were measured using a profilometer. The wear rate was calculated as difference of final minus the initial roughness (ΔSR=FSR-ISR). For statistical analysis t-test and one-way ANOVA test were used by GraphPad Prism version 5.03 statistical software. The level of significance was set at p<0.05. Results: The erosive wear rates (mean±SD, μm) after exposure to acidic beverage were: 0.30±0.03 (Ketac Molar), 0.28±0.04 (Fuji II LC), 0.27±0.00 (Filtek Z550), 0.23±0.01 (X-tra fil), 0.20±0.00 (Twinky Star) and 0.14±0.01 Dyract Extra, respectively. There were significant differences between the tested materials (p<0.05). Conclusions: Dental filling materials had different behaviour under the same erosive condition, however all investigated aesthetic restorative materials showed surface degradation. These findings suggest that erosive wear resistance of tooth coloured restoratives could influence their longevity in intraoral acidic conditions. Acknowledgements: The study was supported by the Internal Research Grant no. 5/30.01.2013 of the University of Medicine and Pharmacy of Tirgu Mureş.


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