News from jobs.co.uk

PhD Scholarship

Manufacturing And Characterisation Of Titanium Based Dental Implant

University of Sheffield - Department of Mechanical Engineering

Application deadline: 07 January 2010.

Call for abstracts: 88th General Session & Exhibition of the IADR

88th General Session & Exhibition of the IADR
Barcelona, Spain, July 14-17, 2010.
www.iadr.org

Abstracts can be submitted online HERE. The deadline for abstract submission is February 5, 2010. As on previous IADR conferences, one person may present only one abstract but can be co-author on an unlimited number of abstracts.

More than 4500 delegates are expected and more than 3000 abstracts submitted. There will be oral and poster discussions as well as traditional poster sessions. All delegates will receive continuing education credits according to the ADA CERP.

The new way of abstract presentation is through poster discussion sessions designed for up to 7 individual presentations. Abstracts in these sessions will be presented as posters with up to 3 PowerPoint slides in addition. Each presentation will last for 5 minutes followed by 2 minutes of discussion.

Posters will be displayed vertically, rather than horizontally. Poster dimensions will be 0.93 m (width) x 2.22 m (height).

There will be more than 20 subject areas including dental materials, cariology, dental anesthesiology, implantology, microbiology, mineralized tissue, neuroscience/TMJ, oral&maxillofacial surgery, periodontology, prosthodontics, pharmacology, pulp biology etc.

More information and detailed instructions can be found HERE.

Poll: What type of adhesive system do you use in your practice?

Please, select one or more answers from the poll in the sidebar.

Adhesive systems are nowadays classified according to the number of clinical application steps and adhesion strategy. This is one of the most widely accepted classifications in both clinical practice and scientific literature.



(a) Three-step etch-and-rinse systems: acid etching with phosphoric acid followed by the application of primer and bond from separate bottles;
(b) Two-step etch-and-rinse systems: acid etching with phosphoric acid followed by the application of primer and bond which are in one bottle;
(c) Two-step self-etch systems: self-etching primer and bond are in separate bottles;
(d) One-step self-etch systems (also known as "all-in-one" systems): all components are in one bottle

Feel free to leave a comment about your experience with any particular adhesive system.

In clinical practice, I'm using a two-step etch-and-rinse system. In PhD research, I've studied the degree of conversion and elution of unreacted monomers from a wide range of adhesive systems. Some of these results have been published in scientific dental journals and some are in press and will be published soon.

Though one-step (all-in-one) self-etch systems are currently marketed, results from many in vivo and in vitro studies suggest that these systems often have inferior properties compared to two-step self-etch and etch-and-rinse systems

Textbook of Restorative Dentistry

It is my pleasure and honour to announce that the Textbook of Restorative Dentistry (original title: Osnovi restaurativne stomatologije) has been published by my professors at Belgrade University School of Dentistry Dept. of Restorative Dentistry and Endodontics: Slavoljub Zivkovic, Mirjana Vujaskovic, Katarina Pap, Djurica Grga, Aleksandra Lukic and Nevenka Teodorovic.

This is the official textbook for undergradute students but may be very helpful to dental practitioners who have some questions regarding restorative procedure.

The book is divided in four parts. Part I presents the biology of pulp-dentine complex, its ultrastructure, but also important physiological and biochemical aspects. This chapter also explains the basics of caries etiology, pathogenesis and diagnostics.

Part II details the equipment and instruments for restorative treatment as well as techniques for caries removal.

Part III explains cavity preparation procedures according to traditional Black's principles and the adhesive cavity preparation for resin-based materials. Cavity preparation for indirect restorations is also explained. Some basic gnatological requirements in restorative treatment are mentioned in Part III.

Part IV addresses all dental materials in restorative dentistry. It contains basic clinical characteristics of materials for temporary fillings, for pulp cappings, amalgam, glass-ionomer cements, resin-based composite materials and adhesive systems as well as materials for indirect restorations.

News from jobs.ac.uk

Research Fellow in Tooth and Peridontal Tissue/Biomechanics/Biomedical Engineering
(Click for more information)

Faculty of Engineering

University of Leeds - School of Mechanical Engineering

Salary: £29,704 to £35,469. It is likely that an appointment will be made at or below £31,513 p.a.

Application deadline: 8 December 2009

Wiley-Blackwell books: Dental Materials at a Glance [20% off]

A couple of days ago, I got an email from Wiley-Blackwell offering certain dental books at discount, 20% off the original price.

Among the books at discount is "Dental Materials at a Glance" by J. Anthony von Fraunhofer, Professor Emeritus at the Baltimore College of Dental Surgery Dental School, University of Maryland and formerly was Professor and Director of Biomaterials Science in the Department of Oral and Maxillofacial Surgery.

I'm not quite sure why I got this offer, either because I subscribed to the newsletter from Wiley-Blackwell or because I already purchased at least one book. Anyway, I'm considering to buy Dental Materials at a Glance since it's now only $27.19. Having bought another book from this "At a Glance" series (Medical Statistics at a Glance), I assume this book about dental materials is written in a similar succinct and readable way with many useful illustrations.

It contains 28 chapters on 72 pages, i.e. 2-3 pages per chapter, which seems to be the pattern for all books from this series. According to the table of contents, the first part looks like a glossary of scientific terms relevant to any dental materials scientist. The second part seems to be a short overview of important properties of contemporary dental materials. There's also a free downloadable chapter HERE.

Nano-filled resin-modified glass-ionomer cement: "nano-ionomer" Ketac N100

In addition to conventional and resin-modified glass-ionomer cements, a nano-filled resin-modified glass ionomer cement, or “nano-ionomer”, was developed by 3M ESPE a couple of years ago – Ketac N100.

It is stated by the manufacturer that indications for the use of this nano-ionomer include primary teeth restorations, small Class I, Class III and IV, temporary restorations, filling defects and undercuts, “sandwich” technique with resin-based composites, core build-ups with min 50% of the remaining tooth for support.

The nano-ionomer is based on the acrylic and itaconic acid copolymers necessary for the glass-ionomer reaction with fluoroaluminosilicate (FAS) glass and water. The nano-ionomer also contains a blend of resin monomers, BisGMA, TEGDMA, PEGDMA and HEMA which polymerize via the free radical addition upon curing and it is stated that the primary curing mechanism is by light activation. The originality of this glass-ionomer cement is the inclusion of nano-fillers which constitute up to two thirds of the filler content (circa 69 wt%).

Other advantages stated by the manufacturer are a simplified procedure which requires the priming but not the separate conditioning step and a precise dispensing and mixing “clicker” mechanism.

In spite of its uniqueness amongst other dental formulations, the nano-ionomer has not been investigated to a greater extent in the scientific dental literature. Medline search using the keyword “Ketac N100” resulted in only 4 papers in international peer-reviewed journals. Another paper was found using the keyword “nano-ionomer”. It is my pleasure to mention that the first of these 5 papers was done in Serbia by my colleagues from the Paediatric Dept of the School of Dentistry, Belgrade and the Dept. of Dentistry School of Medicine, Novi Sad.

It has been reported that fluoride concentration on material surface is similar for Ketac N100 and other glass-ionomer cements from the Fuji “family” but Ketac N100 showed less porosities and surface cracks than Fuji materials (Markovic et al 2008).

A study on bonding orthodontic brackets showed significantly lower shear bond strength for Ketac N100 compared to a conventional light-cure orthodontic bonding adhesive (Transbond XT). However, it has been suggested that this nano-ionomer may be used for bonding orthodontic brackets since the obtained shear bond strength is within clinically acceptable range (Uysal et al. 2009).

Another study using the shear bond strength as an adhesion parameter showed that Er:YAG laser dentine pre-treatment results in lower bond strength values compared to acid etching or a combined acid-etching and laser pre-treatment (Korkmaz et al. 2009).

A study on microleakage around Class V cavities showed that Er:YAG preparation results in greater microleakage than a conventional cavity preparation with a bur when a nano-ionomer (Ketac N100) and a nano-composite (Filtek Supreme XT) were used as restorative materials (Ozel et al. 2009).

In a study by Leuven BIOMAT Research Cluster it has been concluded that Ketac N100 “bonded as effectively to enamel and dentin as a conventional glass-ionomer (Fuji IX GP), but bonded less effectively than a conventional resin-modified glass-ionomer (Fuji II LC). Its bonding mechanism should be attributed to micro-mechanical interlocking provided by the surface roughness, most likely combined with chemical interaction through its acrylic/itaconic acid copolymers” (Coutinho et al. 2009).

More research is needed to investigate other mechanical properties of the nano-ionomer, its biochemical stability in the oral environment, fluoride release etc. Ultimately, well-designed randomized clinical trials will reveal the longevity and anti-cariogenic effect of this material in clinical conditions.

References:

• Markovic DLj, Petrovic BB, Peric TO. Fluoride content and recharge ability of five glassionomer dental materials. BMC Oral Health 2008; 28:8-21.
• Uysal T, Yagci A, Uysal B, Akdogan G. Are nano-composites and nano-ionomers suitable for orthodontic bracket bonding? Eur J Orthod 2009; Apr 28 [epub ahead of print]
• Korkmaz Y, Ozel E, Attar N, Ozge Bicer C. Influence of different conditioning methods on the shear bond strength of novel light-curing nano-ionomer restorative to enamel and dentin. Laser Med Sci 2009; Aug 18 [epub ahead of print]
• Ozel E, Korkmaz Y, Attar N, Bicer CO, Firatli E. Leakage pathway of different nano-restorative materials in class V cavities prepared by Er:YAG laser and bur preparation. Photomed Laser Surg 2009; 27:783-789
• Coutinho E, Cardoso MV, De Munck J, Neves AA, Van Landuyt KL, Poitevin A, Peumans M, Lambrechts P, Van Meerbeek B. Bonding effectiveness and interfacial characterization of a nano-filled resin-modified glass-ionomer. Dent Mater 2009; 25:1347-1357.