Winner 2001 - The IADR.CED Visiting Scholar Stipend

 Alp Dabanoglu

 

25th November, 2002

 

 

Dear Board Members of IADR-CED,

 

 

I would like to present the following report that consisting the studies, experiences, and informations that I have gained in my visit from the Dentistry School of Ludwig Maximilians University in Münich.

 

Respectfully Yours,

 

 

Med. Dent Alp DABANOGLU

     University of Istanbul

       Faculty of Dentistry

      Department of Conservative Dentistry

 

 

 

STUDY REPORT

 

I was invited to the Dental School of Ludwig Maximillians University by Prof. Dr. Hickel being awarded by the Visiting Scholar Stipend given by the IADR-CED to give the young research assistants the opportunity to gain experience and knowledge, and to become familiar with the laboratory equipment and systems, and by the way to complete an authorised research project under these circumstances.

 

In this report that I have prepared as there is a little time left in my working period, I am telling about the researches I have completed, the knowledge I have gained, the laboratory equipment that I have learnt to operate, the working conditions here and my opinions about the culture and the environment.

 

Completed Studies,

1.      In-vitro evaluation of marginal integrity and microleakage of Ormocer based materials with different cavity design. (Main study project)

2.      Wear and fatigue properties of 28 new composite materials

3.      Setting stress of 10 composite materials using different curing methods

4.      Quantitative and qualitative marginal integrity of seven new self etching primers and one 3-step adhesive materials

5.      Mechanical surface properties of 10 different composite materials after different curing procedures

6.      Mechanical surface properties of composite based materials after wear study in different regions.

 

Equipment’s which are used in these studies

·        Thermocycling Machine

·        Fatigue Loading Simulator

·        Scanning Electron Microscope

·        ACTA wear and fatigue machine

·        3D Laser Scanner

·        Stress-strain analyser

·        Nanoindentation machine

 

Study methods and techniques

·        Ageing of dental materials,

·        Scanning Electron Microscope technology and how to use it,

·        Quantitative analysis method in evaluation of marginal integrity of filling materials,

·        Quantitative and qualitative methods for microleakage evaluation.

·        Wear and Fatigue properties of dental materials and their evaluation,

·        Three-body wear evaluation method,

·        Taking more than 250 photos from the sample by SEM, the experience of handling SEM is increased.

·        Many information is obtained about the stress value of dental materials during polymerisation procedure,

·        Effect of different curing methods when occurring  stress of composite materials

·        Adhesive materials and their properties,

·        Comprehensive information about self-etching primers

·        Obtaining the SEM photos of Hybrid Layer and tag formation of adhesive materials by Nikaido technique.

·        Determination of the nano mechanical properties with nano-indenter machine

·        Effects of different curing procedure on the nano mechanical properties of composite materials

 

In addition to these studies, I have learnt and got information about following subjects;

·        General equipment’s, discipline and working procedures of a Dental Research Laboratory. Also I have gained knowledge on the meaning of Tribology and its systems.

·        Computerisation of the results which are obtained from the mechanical equipment’s. Also I have got some information concerning software.

·        Comprehensive information about improvement in the light-curing source which is used for polymerisation of dental materials.

·        I got some information about Universal Testing Machine and CEREC I,II, and III systems.

·        I have attended a course that called emergency in dentistry.

·        I have obtained all papers and journals that I need, from the library.

 

 

THANKS

 

I would like to express my thanks;

 

To IADR-CED for the Visiting Scholar Stipend.

 

To Prof. Reinhard Hickel, Prof. Kremers, Prof. Kunzelmann and Dr. Manhart from the Ludwig Maximilians University

 

To Prof. Fatma Koray, supervisor of my study project, from the Istanbul University

 

 

 

 

Med. Dent Alp DABANOGLU

     University of Istanbul

       Faculty of Dentistry

      Department of Conservative Dentistry

 

 

1969 Marginal Integrity and Microleakage Evaluation of Cervical Restorations

 

A. DABANOGLU1, K.H. KUNZELMANN2, R. HICKEL2, F. KORAY1, and J. MANHART2, 1 Istanbul University, Faculty of Dentistry, Dept. of Conservative Dentistry, Turkey, 2 Dental school of the LMU, Dept of Restorative Dentistry and Periodontology, Munich, Germany

 

Objectives: The aim of this in-vitro study was to evaluate the marginal integrity and microleakage of cervical dentin bonded ormocer restorations with or without placing flowables after different kind of cavity preparations.

 

Methods: Thirty-two caries-free human premolars were divided into four equal groups. Standardized conventional Class V cavities for GroupA (GrA) and GroupB (GrB) and Nodge Shape cervical cavities for GroupC (GrC) and GroupD (GrD) were prepared at the buccal surfaces of teeth. Half of finishing lines (circumference 10mm, depth 2mm) of cavities were placed within dentin. Material application completed as follows; for GrA and GrC-Admira (Voco, Cuxhaven); for GrB and GrD-Admira + AdmiraFlow (Voco,Cuxhaven). Teeth were then subjected to thermocycling (5/55 0C, 2000 x) and fatigue load cycling (force=50N, 50000x). Before and after artificial ageing procedure, epoxy replicas were produced for quantitatively assessment of marginal integrity in the SEM. Specimens were stored in methylene blue (5%) for 3 hours and sectioned to measure the microleakage quantitatively. Statistical analysis was performed by using Kruskal-Wallis and Dunn's Multiple Comparison test.

 

Results: Difference in values of gap formation were statistically significant between GrB (10.78±4.8) and GrD (20.18±2.7) on dentinal margin (p<0,05) and between GrB (7.76±2.4) and GrC (16.48±3.6) on the enamel margin (p<0,05). Microleakage in GrB (415.9±157.2) was less than GrC (1347.0±386.8) on dentin limited margin (p<0,001) as it was GrB (243.5±96.31) less than GrC (921.5±327.0) on the enamel limited margin (p<0,001).

 

Conclusion: Cavity design and the application of flowables prior to the restoration effect on the marginal integrity and microleakage of the cervical restoration. This study was supported by IADR-CED Visiting Scholar Stipend 2001.

 

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