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Wednesday, 13 October 2010

Monomer elution from a dental composite

Recently, I started a series of studies on monomer elution from composites with colleagues from University of Belgrade School of Dentistry and Faculty of Technology and Metallurgy. One of these experiments was presented a month ago at an international material science and engineering conference YUCOMAT.

The nano-hybrid composite Filtek Z250 (3M ESPE) was used to study elution kinetics of monomers UDMA and HEMA over 28 days post-immersion in either distilled water or 75% ethanol. Kinetic models were proposed and it was shown that monomer elution followed the first order law for both UDMA and HEMA irrespective of the medium. However, there were some differences in that UDMA eluted more rapidly during the first 24 h and then much more slowly over the 28-day period. This indicates that during the first 24 h elution from the sample surface occurred whereas the slow phase corresponds to monomer elution from inside the polymer. On the other hand, HEMA did not start to elute immediately, but only after 24 h and the eluted concentrations increased over the 28 days. Though HEMA is not a genuine ingredient of the studied composite, its slow elution and small eluted amounts seem to support a previous statement by other authors that HEMA could elute as a product of degradation of UDMA. (We are currently investigating this hypothesis.)

Monday, 4 October 2010

Dental Materials Blog: Year 1

It has been a year since I started writing on this blog. During this first year, nearly 6700 visits and 12000 pageviews have been made by more than 5300 unique visitors. The average number of visits per day has been increasing constantly and currently is 17.70. What I am particularly proud is that one fifth of all visitors have returned and visited the blog more than once. Another important figure is that visitors come from more than 120 countries in the world (Figure 1.). The importance of this information is not so much related to the blog itself, but shows that in almost every corner of the Earth people search for dental information and want to expand their knowledge.
Figure 1. Map overlay

The most frequently visited posts are related to MTA in endodontics and the list of free full texts, self-adhering composite Vertise Flow and nano-filled, resin-modified glass ionomer Ketac N100. Likewise, the most frequently used keywords are "dental materials", ""MTA dental material", ""MTA dental", "mineral trioxide aggregate",  "Vertise Flow"...

Comments were disabled for most of the year, because I haven't noticed there was a problem, but a visitor drew my attention to it. Comments are now fixed and those received so far are all very positive.

I would like to encourage fellow researchers and clinicians to contribute to the Dental Materials Blog with their own posts, it is free and the choice of topics is entirely up to the authors.