SHORT-TERM RESEARCH TRAINING PROGRAM IN
DENTAL AND CRANIOFACIAL
BIOENGINEERING
May 21–July 27, 2007
University of Missouri-Kansas City (UMKC)
School of Dentistry

The UMKC School of Dentistry invites applications from senior undergraduate students, graduate students and postdoctoral fellows to participate in a leadership and research training program designed to develop a new interdisciplinary research workforce in Dental and Craniofacial Bioengineering. This 10-week summer program will provide participants with intensive didactic instruction and research experiences in dental and craniofacial bioengineering.

2006 Trainees:
Back row (left to right): Marlieke de Bruijn, Fernando D. Nussenbaum, Amy Becker, Grant Snider, Rick Weber
Front row (left to right): Mona M. Kalayeh, Natalie Gorman, Jenny Melander, Jessie Huber, Geminia T. Carey

Philosophy and Overview

The training program is based on the philosophy that the fusion of knowledge from diverse disciplines can lead to creative approaches to intractable problems involving the oral, dental and craniofacial system. The identification and development of effective solutions to the multifactorial nature of human disease requires research approaches that cross traditional discipline boundaries and integrate knowledge from various fields of investigation. These new approaches require investigators from diverse backgrounds working collectively in cross-disciplinary research teams to address and resolve complex biomedical problems. Because of the interdisciplinary emphasis of UMKC’s research and educational programs, this institution is uniquely positioned to respond effectively and directly to the goal of training a new interdisciplinary workforce in dental and craniofacial bioengineering.

Rick and Amy are developing new software that will allow the integration of hyperspectral imaging data.
They are working as key members of a group to develop a new computing platform for data integration,
analysis and visualization of hyperspectral imaging results.

Projects

Micro-Scale Structure/Property Changes in Dentin Adhesives
Mentors: Dr. Paulette Spencer, Dr. Anil Misra, Dr. Yong Wang, Dr. Elisabet Kostoryz
Post-doctoral Fellows: Drs. Qiang Ye and Xinglin Guo
Ph.D. Student: Orestes Marangos

Introduction
If composite resins are to be considered a viable alternative to dental amalgam, the durability of the dentin/adhesive bond must be improved. Under in vivo conditions this bond can be the first defense against substances that penetrate and ultimately, undermine the composite restoration. Our recent in situ characterization of the molecular structure and micro-mechanical properties of the bond formed at the dentin/adhesive interface has indicated a serious limitation, i.e., physical separation of the commercial BisGMA-based adhesives upon mixing with water in the demineralized dentin substrate. The critical dimethacrylate (BisGMA), the component contributing most to the cross-linked polymeric adhesive, infiltrated a fraction of the wet, demineralized dentin substrate. The focus of this work is the development of methacrylate-based adhesives that are water-compatible and resistant to breakdown under conditions simulating the oral cavity.

Overview
Performance of these adhesives when subjected to the environmental and mechanical loading found in the oral cavity is of significant interest. Our lab is engaged in the development of the next generation of adhesives, i.e. adhesives that are water compatible and durable under conditions that simulate function in the mouth. As part of the characterization studies, cured specimens of model adhesives formulated to be water compatible and resistant to enzymatic breakdown will be prepared. These specimens will be subjected to aqueous storage and thermal cycling, thus simulating environmental challenges in the mouth. Following aging, the specimens will be subjected to mechanical loading to determine their viscoelastic properties. The specimens will be characterized using various analytical modalities, e.g. scanning acoustic microscopy, FTIR, Raman, etc. to determine changes in the micro-scale structure/properties of the model adhesive formulations as a function of aqueous and thermal challenge.

From the project, trainees will gain “hand-on” experience in the analytical techniques used in micro-scale structure/property characterization of materials. They should gain an understanding of:
1. The factors that influence the durability of dentin adhesives under conditions simulating clinical function.
2. How mechanical properties of adhesives are measured
3. How micro-mechanical properties at the material/tissue interface are measured
4. How polymerization kinetics influences the structure of dentin adhesives
5. How to evaluate molecular structure at the adhesive/dentin interface
6. How aging affects the structure/property relationships of the adhesive
7. Development of testing procedure

Multi-Resolution Analysis of Hyperspectral Data and Images Implementation in the Structure Property Function (SPF) Software
Mentors: Dr. Yong Wang, Dr. Ganesh Thiagarajan

Introduction
Determining the structure/property relationships of tissues or materials depends on analyses using a variety of analytical instruments. In most laboratories, these complementary analyses are performed on a heterogeneous mix of instrumentation which has been acquired from different manufacturers. Each instrument uses the software unique to its vendor, and frequently, the data from each instrument must be stored in a proprietary format. Software peculiar to a particular instrument may have difficulty reading different data types. These limitations may force investigators to evaluate results independent of other analyses.

The overall focus of this work is the development of a comprehensive computing platform system that can efficiently and intelligently integrate, manage, analyze, extract and visualize large hyperspectral imaging datasets. Hyperspectral imaging presents many challenges from the point of view of data and signal analysis due to the large amount and high dimensionality of the data. Existing software is not well suited to the analysis or extraction of such complex data.

Overview
A common data platform (CDF) is currently under development in a Matlab environment to analyze data from instruments such as micro Raman spectroscopy, Fourier Transform Infrared (FTIR) which have different spatial resolutions. The objective is to develop a common platform in which such multi resolution data can be efficiently and quickly analyzed. A GUI is currently under development for the past two years with a number of functionalities already built in to achieve this goal. Work is also in progress to develop algorithms to develop imaging based on analytical techniques such as K-means clustering, principal component analysis (PCA) etc. The proposed project would involve collection of actual data on the same specimen (dentin/adhesive sample) from different instruments (Raman, FTIR and SAM) and calibrate the SPF software to perform analysis on such multi-resolution data. Analysis outcomes would include the characterization of the structure-property-function of the dentine/adhesive junction sample. The work would involve the aspects of experimentation such as data collection from the sample and also development of software in a Matlab environment.

From the project, trainees should gain an understanding of:
1. Why data integration is important to the visualization of information recorded from widely varying analytical techniques
2. How to manage data integration without compromising the integrity of the original, complex datasets
3. How to construct quantitative structure/property data images from the fused datasets
4. How data integration facilitates pattern recognition in large, high dimensional and complex datasets
5. Methods of software validation

Modeling the structure/property relationships in the temporomandibular joint
Mentors: Dr. Trent Guess, Dr. Paulette Spencer, Dr. Anil Misra, Dr. Yong Wang

The overall goal of this project is to develop a computational model of the temporomandibular joint (TMJ) that includes representation of bone, cartilage, muscle, ligaments, and the temporomandibular disk. The disk is an important tissue in joint function and the specific goal of the summer research project is to both characterize and develop a computational model of the tissue. The objective of the project is for the trainees to experience the synergy between empirical and computational methods of capturing structure/property relationships in the temporomandibular joint. The students will work to measure the material properties of the TMJ disk, apply these to a computational model, and then to experimentally verify the outcomes of the model.

From the project, trainees should gain an understanding of:
1. Why study of the structure/property relationships of the TMJ is important
2. How mechanical properties of the TMJ disk are measured
3. How these properties can be incorporated into a computational model
4. How a model can then be used to explore structure/property relationships
5. Methods of model validation
6. Development of testing procedures
7. Sensor calibration
8. Computational methods in musculoskeletal biomechanics

Natalie measures the deformation of a water-compatible adhesive formulation.
Working under the direction of post-doctoral research fellow, Dr. Qiang Ye,
Natalie and her partner, Jenny, synthesized this new adhesive. This work has been
accepted for presentation at the International Association of Dental Research meeting in
New Orleans in March, 2007, and Natalie and Jenny are co-authors on the abstract.

Chemomechanical Characterization of the Interfacial Bond Between Adhesive Resins and Clinically Relevant Substrates
Mentors: Dr. Yong Wang, Dr. Brenda Bohaty, Dr. Paulette Spencer, Dr. Anil Misra
Post-doctoral Fellows: Dr. Xiaomei Yao

Introduction
To date, dentin bonding does not provide a seal that can prevent the penetration of bacteria or other chemical substances at the composite/adhesive/tooth interface. Leakage at this interface leads to recurrent decay, post-operative sensitivity, breakdown of the bond, and premature failure of the composite restoration. If composite resins are to be considered a viable alternative to dental amalgam their clinical performance must be improved. Such improvement depends upon establishing a bond at the dentin/adhesive interface that is not only strong enough to resist the stresses associated with polymerization shrinkage, but also impervious to oral fluids.

Factors associated with resin restorations and bonding adequacy are further complicated because under clinical conditions bonding may ultimately be performed on dentin that is both caries-free and caries-affected in some portions of the same cavity preparation. The literature suggests that caries-affected dentin in permanent teeth is partially demineralized and has a lower Knoop hardness value. There is further evidence that suggests that this type of dentin is also porous and disorganized, and has mineral precipitates that remain in the tubules. While there is very little literature characterizing caries-affected primary dentin, it is likely that these structural dentinal changes can also be found in caries-affected primary dentin.

Overview
Understanding the structure and properties of the bond that forms at the interface between adhesive resins and bio-altered, clinically relevant substrates requires high resolution analytical techniques that allow direct nondestructive, in situ detection of the variable composition and in homogeneity across the length and breadth of the interface. The purpose of this investigation will be to characterize the structural properties of the dentin/adhesive interface in caries-free (CF) and caries-affected (CA) primary and permanent dentin using complementary techniques. Recovered caries-free and caries-affected permanent and primary teeth with be restored with composite resin restorations. The teeth will be sectioned and analyzed with various imaging techniques, including Raman, scanning acoustic microscopy and potentially scanning electron microscopy. The project will be designed so that the mechanical and chemical properties of the adhesive/dentin interface can be analyzed.

From the project, trainees will gain “hand-on” experience in analytical techniques used in nano- and micro-scale morphologic characterization of material/tissue interfaces: They should gain an understanding of:
1. The effect of the substrate on reactions at the adhesive/dentin interface
2. How factors such as moisture, mineral content and distribution effect morphologic relationships at the adhesive/dentin interface
3. How disease affects the morphologic structure at the adhesive/dentin interface
4. Development of testing procedure
5. The relationship of structure to micro-mechanical properties at the adhesive/dentin interface
6. How adhesive/dentin interfacial structure/property relationships are used in the development of new adhesives

“Wow! You can do that? I did not know that anyone could measure mechanical properties
in situ at micrometer resolution.” Faculty mentor, Dr. Yong Wang, uses the high frequency
scanning acoustic microscope to help Mona complete her analysis of the structure/property
relationships at the material/tissue interface. This work has been accepted for presentation at the
International Association of Dental Research meeting in New Orleans in March, 2007.
Mona and her research partner, Marlieke, are co-authors on the abstract.

Stipend

Pre-doctoral trainees will receive a $3,800 stipend and post-doctoral trainees will receive an $11,700 stipend for the 10-week period. Program participants will receive reimbursement for travel costs to the UMKC campus and a $1,600 housing allowance.

Admission and Information

Applicants to the Short-Term Research Training Program in Dental and Craniofacial Bioengineering must be U.S. citizens or permanent residents. Applicants should submit (via email) a letter of intent and resume including GPA and references to Program Director Dr. Paulette Spencer at: spencerp@umkc.edu. Applications must be received by March 19, 2007. Invitations to participate in the program will be announced in early April 2007.

Grant and Jessie explain the sites within the methacrylate matrix that are
accessible to attack and breakdown by enzymes that are present in the mouth.

Comments from past attendees

I JUST WANTED to send you one last email thanking you for the wonderful opportunity I had this summer. It was a great experience doing cutting-edge research for CRISP. I cannot begin to tell you how much I learned. I was very lucky to be a part of this new paradigm. I will proudly hang up my certificate when I some day get an office of my own. My parents were very excited to get to see my presentation and are still raving about it to all their friends and family. Thanks again for your kindness and support of such a wonderful summer. I hope to see you both soon!

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THANKS EVERYONE for such a great program! The internship overall was a wonderful learning experience. I can now take what I’ve learned here and potentially apply it to a senior project. I think that the internship was a great success.

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OVERALL, I FEEL these 10 weeks have been an extremely valuable learning experience. There are very few programs that introduce you to so many different subjects and fields of study. I think that is the main strength of this program, to show how a truly interdisciplinary department works together toward a common goal. Oftentimes research departments are too segregated and too competitive in their work, trying to be the group to publish the most papers and get the most grant money. During my time here I never got the sense that it was all about the money. That is something that is actually quite important when bringing in young scientists. Another strength is the quality of the faculty at UMKC. Everyone that was a part of this program was extremely helpful and extremely knowledgeable in their field. I never experienced a problem communicating with the faculty or graduate students on any level.

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WHILE WORKING in an interdisciplinary setting, I had the opportunity to meet people of different studies (various types of engineers, biology majors, dentists, computer scientists, etc.). I’ve learned that input from many people with different experiences can solve a problem faster than one person working by trial and error. This is something uncommon to other types of research programs. Most importantly, I had a great summer. I can’t think of a better way I could have spent my time.

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THIS PROGRAM exposed students to dentistry and its problems in a way that is very effective. I gained an incredible amount of useful information to take back with me. I also feel that the research I was exposed to was very useful and exciting. I like that the research was left up to me. I was not hand fed what to do, and I had to make decisions on my own.

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I ENJOYED this research experience so much because it integrated the clinical as well as the research aspect of dentistry. I have truly enjoyed this summer research experience at UMKC-School of Dentistry and am truly grateful for having been given the opportunity to participate as a “pioneer” in this program. As a pre-dental student, this program has not only given me the opportunity to work at a dental school all summer (a dream come true for a pre-dent) but it has more importantly opened my eyes to the research aspect of dentistry. With the experience I gained this summer I am very eager and interested to pursue research throughout my undergraduate career and then in dental school by entering into a PhD/DDS program.

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CLOSE INTERACTION with professors and post-docs was excellent!

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THE DIDACTIC INSTRUCTION portion was very interesting. There was a good mix of clinical/research/oral biology information. This aspect of the program is good because it helps trainees look beyond the narrow focus of their project to the broad field of dental science.

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GOOD MIX of students from different academic levels and backgrounds

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I ENJOYED this summer program because it provided individuals the opportunity to participate in research projects that they otherwise might not be able to. By offering interdisciplinary programs, individuals from different backgrounds were able to come together and contribute innovative ideas and views. This program allowed me to do biomedical research pertaining to biomechanics, even though I specialized in signal processing for graduate school. As a result, this research provided me with a different area of biomedical engineering, and I was able to use programs and modeling software that add to my knowledge of the area of bioengineering as a whole. Overall, the STRTP was organized very well. As the prestige of this program grows, I will be glad to say I was in one of the pioneering groups.

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OVERALL, MY SUMMER experience with the Short Term Research Training Program was a positive one. I feel like the interdisciplinary aspect of the program provides participants with a unique opportunity for exposure to a variety of disciplines related to the dental field. In this same respect, I thought that the Friday talks on both the clinical and the scientific aspects made for a good balance of the topics the program exposed us to.

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I ENJOYED the experience of giving a research presentation; this gave us practice in a valuable skill no matter where our future jobs take us.

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MY OVERALL REVIEW of the program is very positive. I was very pleased, as a scientist, to work in a different field. I thought that the mentors were very helpful, and were a main reason that the program was so successful.

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OVERALL I FELT this was an excellent program. The interdisciplinary nature of the program impressed me greatly. Not being an engineer, I felt this was a wonderful learning experience for me. Not only did I get exposure to a new field, but I felt that because my background was slightly different I was able to make unique contributions.

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WORKING LUNCH on Friday was good. Just being with other trainees was a nice way to end the (stressful) week

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THE DIDACTIC TRAINING portion of the program was great. It was a good length (not too long), and it gave me a good introduction into several areas within the dental field. I also liked the balance between both clinical and research work.

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WHILE I HATED IT AT THE TIME, having to prepare for that first presentation practice was a good idea. It forced me to get organized and begin thinking about the conclusions for our research.

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EVERYONE WAS VERY HELPFUL and encouraging. I never felt intimidated to ask questions or seek help.

Grant uses Raman spectroscopy to collect a chemical image of an adhesive that was degraded
by exposure to enzymes. The work from this project has been accepted for presentation at the
International Association of Dental Research meeting in New Orleans in March, 2007. Grant
and Jessie are co-authors on the abstract.

Faculty

The UMKC Center for Research on Interfacial Structure and Properties (UMKC-CRISP) — under the leadership of Director Dr. Paulette Spencer and Co Directors Drs. Mehmet Bilgen, J. Lawrence Katz, Anil Misra, Lisa Friis and Yong Wang — serves as the locus for the program along with an outstanding faculty of engineers, scientists and clinicians working collaboratively among the UMKC Department of Oral Biology, the UMKC School of Computing and Engineering and the University of Kansas Medical Center.

Funded by: The National Institutes of Health (NIH)

UMKC is an equal opportunity/affirmative action institution.