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.)

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.

Journal of Esthetic and Restorative Dentistry gets its first impact factor

A Miletic et al. study among the top 5 cited papers

In the latest list of SCI Journal Impact Factors 2009 published by Thomson Reuters, Journal of Esthetic and Restorative Dentistry is listed with the impact factor of 0.797. The Journal thanks all authors, reviewers and readers and allows free access to the top cited articles. Easy online submissions through ScholarOne Manuscripts are encouraged as this speeds up the review process. Hopefully, the Journal will maintain a growing influence in the scientific literature and increase its impact factor in the future.


It was a pleasure to see that one of the papers I did with my colleagues at the University of Belgrade School of Dentistry was among the top 5 cited articles in the Journal of Esthetic and Restorative Dentistry.

Miletic V, Ivanovic V, Dzeletovic B, Lezaja M.
Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing.

I look forward to submitting the results of my current studies to the Journal of Esthetic and Restorative Dentistry.

Recent books on dental materials II

The previous "Recent books" list on this blog is updated with, according to some scholars, the best book in this field.

Now in its ninth edition, Materials Science for Dentistry by Professor Brian W. Darvell (2009, 688 pages) continues its reputation as the most authoritative available reference for students of dentistry. It is also a valuable resource for academics and practitioners in the field. 

For more information about the book and the author, please visit publisher's website. 

News from jobs.ac.uk

Research Fellow

University of Birmingham - School of Dentistry

Fixed Term for 12 months

The main purpose of the post will be to undertake a series of activities that have been identified which will contribute to the creation of a mechanistic understanding of how polymer adhesives interact with ceramic surface defects and confer reinforcement. Innovative steps will be made to optimise ceramic reinforcement ultimately leading to novel solutions to prevent the fracture of dental ceramic restorations in service.

The candidate should have a degree in Materials Science, Engineering or Chemical Engineering and hold a PhD or be near completion of a PhD.

Salary from £27,319 to £35,646 a year, with potential progression to £37,839 a year. Maximum starting salary £27,319 a year

Closing date: 10th September 2010

Tooth bleaching techniques - clinical steps

Take a look at the clinical steps of tooth bleaching presented by my dear colleague and friend, Tatjana Savic Stankovic BDS, MSc from University of Belgrade School of Dentistry. For more information, contact Dr Savic Stankovic by email tanjeze@gmail.com

If you can't see this presentation, you should download Adobe Flash Player. It's free. Click here.

88th IADR General Session (Barcelona, 2010)

Effect of Preparation and Storage on Adhesive Monomer Conversion

V. MILETIC,  University of Belgrade, Belgrade, Serbia,  
A. SANTINI, The University of Edinburgh, Edinburgh, United Kingdom

Objectives: To study the effect of sample preparation and storage conditions on the degree of conversion (DC) of two adhesive systems using micro-Raman spectroscopy.  
Methods: Sixty samples each of an etch-and-rinse (Excite) and a self-etch (Clearfil 3S) adhesive were prepared on glass slides and allocated to groups G1-G6 (n=10). Thirty samples of each adhesive were prepared on dentine discs according to manufacturer's instructions and allocated to groups D1-D6 (n=5). In groups G1 and D1, each sample was covered with a Mylar strip and cured for 10 s with a bluephase LED unit. In groups G2 and D2, samples were cured without the Mylar strip. Micro-Raman spectra were taken 5 min post-curing. Groups G3-G6 and D3-D6 were covered with Mylar strips, cured according to the same protocol and stored for 24 h: G3 and D3 at 22±2ºC and 45±3% humidity; G4 and D4 at 37±1ºC and 90±2% humidity; G5 and D5 in distilled water at 37±1ºC; G6 and D6 in buffered incubation medium at 37±1ºC. Micro-Raman spectra were taken 5 min post-curing and after storage. Data were analyzed using t-tests and repeated measures ANOVA and the level of significance was α=0.05.
Results: Higher DC values were found on dentine than glass for both adhesives (p<0.05). Higher DC values were found for both adhesives when cured on dentine with than without Mylar strips (p<0.05). Higher DC values were found for Excite cured on glass with than without Mylar strips (p<0.05), but there was no difference for Clearfil 3S (p>0.05). Both adhesives cured on dentine gave higher DC after 24 h storage irrespective of the medium (p<0.05). Excite G3 group and Clearfil 3S G3 and G4 groups showed higher DC values after storage (p<0.05).
Conclusions: Sample preparation methods and storage conditions significantly affected the DC of Excite and Clearfil 3S.

IADR 2010

If you can't see this presentation, you should download Adobe Flash Player. It's free. Click here.