Report

Visit to Leuven BIOMAT Research Cluster, Catholic University of Leuven, Belgium, under the supervision of Prof. Dr Bart Van Meerbeek

The visit took place in October-November 2002. The main goal of the stipend was to conduct a research project “A comparative in-vivo longevity study of a self–etch versus total-etch adhesive”, as previously accepted by the CED Board.

The visit started with a very thorough introduction to the Catholic University of Leuven, its research facilities, co-operation between different departments within the University. Later on I was introduced to Leuven BIOMAT Research Cluster (LBRC) and its staff. I received meticulous training on some of equipment used. I found it very interesting having the chance to get to know research methods applied at the LBRC.

After completing most of my planned research, the enthusiastic & research stimulating atmosphere at LBRC caused me to propose another research project „Technique sensitivity of self-etching primer to dentin and enamel”, which after slight modifications was accepted. Performing the second research project gave me a chance to further improve my lab skills and obtain more of research know-how. The first research project was prepared for an abstract to be presented at IADR meeting in Gothenburg (abstract # 0046), the second will be prepared for future publication.

The staff of LBRC was very helpful and extremely patient despite my endless questions and requests for assistance; they kept eagerly providing me any information or help I needed. It was also interesting to meet Japanese researchers visiting LBRC, to get know their ideas and comments on adhesive technology.

In the meantime I had a chance to meet faculty members and got an inside view on details about the graduate curriculum, postgraduate programs, Belgium’s dental health service and standards. I picked up inspiring details of work organization in the Department.

There was also time to see some sites in Belgium, meet faculty members also on informal occasions, enjoy and taste famous Belgium specialities.

I am very satisfied with the Program, the main achievements in my opinion were not only the research performed and the science transfer, but also a chance for future co-operation with the Catholic University of Leuven.

Jacek Iracki

Department of Conservative Dentistry

Medical University of Warsaw

Miodowa 18

00-246 Warsaw,

Poland

0046 Micro-tensile Bond Strength of a Contemporary Total-etch and Self-etch Adhesive after in vivo Degradation

J. IRACKI¹, J. DE MUNCK², K. SHIRAI³, P. LAMBRECHTS², and B. VAN MEERBEEK², ¹ Medical University of Warsaw, Poland, ² Catholic University of Leuven, Belgium, ³ Hiroshima University, Japan

Long-term durability of the bond between tooth and restorative material is one of the most critical factors affecting the clinical performance of adhesive restorations.

Objectives: The aim of the study was to evaluate the bonding effectiveness of a total-etch and a self-etch adhesive to dentin after 6-month in-vivo service, using a micro-tensile bond strength (µTBS) set-up and Fe-SEM.

Methods: Class-I restorations were placed in 10 human caries-free third molars and pre-molars scheduled for extraction (approved by Committee for Medical Ethics, Warshaw University). The cavities were restored using either a three-step total-etch adhesive (OptiBond FL, Kerr) or a ‘mild' two-step self-etch adhesive (Clearfil SE, Kuraray) along with one resin composite (Z100, 3M Espe). After 6 months of in-vivo service, the teeth were extracted and 2-4 µTBS samples were prepared from each restoration. Samples from in-vitro prepared restorations (stored for 24hr in water) served as controls.

Results:

µTBS (MPa) 24 hr in-vitro ptf/n* 6-month in-vivo ptf/n*

OptiBond FL 30.7 ± 11.5 0/20 27.9 ± 15.2 2/19

Clearfil SE 28.3 ± 8.3 0/16 23.4 ± 7.6 0/12

*ptf/n = Pre-testing failures/ number of samples

Two-way ANOVA and Scheffe's statistical analysis (p<0.05) revealed no significant bond degradation, nor any significant difference between both adhesives tested. The 2 pre-testing failures recorded for the OptiBond FL in-vivo group originated from upper third molars that were difficultly accessible, which consequently may have led to inaccurate adhesive application.

Conclusions: In-vivo degradation up to 6 months seemed not to influence the µTBS of the tested total- and self-etch adhesive. Also Fe-SEM examination did not reveal distinct ultra-morphologic features of bond degradation.

This study was supported by a Visiting Scholar Program from IADR-CED.

81st General Session of the International Association for Dental Research (June 25-28, 2003)