2004 Scientific Abstracts
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1. Reproducibility of Confocal Microscopy in Root Caries Evaluation in Vitro
M.J.Toro *, A. Haider , K. Yi , G. J. Eckert , C. González-Cabezas Indiana University School of Dentistry, USA; Division of Biostatistics, Indiana University School of Medicine, USA Root caries is a widespread dental problem. In vitro root caries models are important tools in preliminary testing of dental products prior to expensive clinical trials. Previous studies in our laboratory have demonstrated that confocal laser scanning microscopy (CLSM) is useful to measure root dentin mineral changes. However, the reproducibility of this technique is unknown. Objectives: To determine the intra- and inter-examiner reproducibility for the measurement of root lesion fluorescence parameters using CLSM. Methods: Blocks of human root dentin from a previous in vitro study on the effect of different treatment regimens on lesion initiation and progression were used. Following analysis of all specimens of this prior study, 29 sections were chosen to represent a range of lesion severity. Four images from each specimen were taken and analyzed by three examiners (M.J.T, A.H, K.Y), independently and then re-taken and re-analyzed 24 h later. The lesion parameters analyzed were: area, total fluorescence and depth. Intraclass Correlation Coefficients (ICCs) and ANOVA were used to assess the intra- and inter-examiner agreement. Results: ICCs for all the parameters showed very good agreement within examiners (0.72-0.96) and between examiners (0.79-0.91). ANOVA showed significant differences within and between the examiners for some parameters. Conclusions: The results of this study showed the CLSM method has an overall good reproducibility. However, extensive training and calibration are required to further standardize the procedure. 2. Fluoride Varnish and Chlorhexidine Gel Effect on Secondary Caries Progression
M. FONTANA1, J. WEFEL2, A. HAIDER1, G.J. ECKERT3, G.K. STOOKEY1, and C. GONZALEZ-CABEZAS.1 (1 Indiana University, School of Dentistry, 2 University of Iowa, Iowa City, 3 Indiana University School of Medicine) Secondary caries (SC) is one of the main reasons for restoration replacement. Objective: To determine the efficacy of a 5% NaF varnish (FV; OMNII, USA) and a 1% chlorhexidine gel (CHXg) in inhibiting progression of SC lesions. Methods: A 1x4x1.5 mm cavity was prepared on the buccal surface of 56 human molars, and restored with amalgam. SC lesions were developed using a microbial caries model for 3 days. Half of each specimen was then painted with an acid-resistant nail varnish to maintain the baseline lesion. Specimens were divided into 4 groups and treated with the following: placebo varnish and placebo gel, placebo varnish and CHXg, FV and placebo gel, FV and CHXg. The varnishes were kept on for 24h, prior to specimens being subjected to 4 more days of bacterial challenge, during which the gel treatments (4 min) were applied at the end of the first 24h, followed by reinoculation with Streptococcus mutans at the end of the second day. Specimens were analyzed for bacterial colonization, sectioned through both baseline and treated lesions, and analyzed using confocal laser scanning microscopy (CLSM) to determine the extent of the change in the lesion after treatment. Results: There were significantly lower (p<0.05) bacterial counts (CFU/ml) with the CHXg than without it, and with the FV than without it. CLSM data indicated a significant reduction in SC wall lesion depth progression for the FV and for the CHXg, but the combined effect (FV + CHXg) was not significant. FV had also a significant effect in reducing overall progression of SC total lesion fluorescence as assessed by CLSM. Conclusion: Application of FV to an active SC significantly slowed down lesion progression. CHXg application had a significant effect only on wall lesion progression. This study was funded by the National Institutes of Health grant #P01 DE13540. 3. Galactose breakdown in Streptococcus mutans is by the tagatose-phosphate pathway
J. COOK* and A.L. HONEYMAN, Baylor College of Dentistry, Texas A&M University System Health Science Center, Dallas, TX, USA. Streptococcus mutans ferments various carbohydrates to form lactic acid, which lowers the pH of the local environment. This change initiates dental caries formation. To identify the galactose fermentation pathway, various molecular probes were used. S. mutans cells were grown in defined bacteriological media containing various carbohydrates and the total cellular RNA isolated. Slot blot hybridizations of the RNA were used to determine the metabolic genes active during fermentation of the carbohydrates. The molecular results obtained indicate the tagatose-phosphate pathway is expressed in the presence of galactose. These molecular results were supported by various genetic knockouts. A galactose-kinase mutant strain maintained the ability to ferment galactose while a strain unable to use lactose totally blocked galactose fermentation. These results indicate the S. mutans ferments galactose exclusively via the lactose utilization genes. This research identifies a target within S. mutans that can be used to block fermentation of lactose and galactose from the diet, with the greatest application to diets that are rich in dairy products. 4. Relationship between Early Childhood Caries and Obesity
Courtney Brooks, Rosie Roldan, Maria Trujillo Objective: Childhood obesity carries with it many co-morbidities; Type II diabetes, orthopedic problems, sleep apnea, and psychological and behavioral problems; and has been associated with high refined sugar intake. Because of the relationship between sucrose and development of dental caries, the purpose of this study is to determine the association between obesity and caries rates in young children. Methods: 812 children aged 2-5 years participated in this study. Patients were enrolled with informed consent given by the parent or guardian. Data collected included the child’s age, ethnicity, weight, height, and def score. Body Mass Index (BMI) was calculated using the Center for Disease Control BMI calculator. Children were divided into five weight classes based on percentile values of BMI: Group I (>95th percentile), Group II (75th-95th percentile), Group III (25th-75th percentile), Group IV (5th -25th percentile), and Group V (<5th percentile). Data analysis consisted of descriptive statistics, analysis of variance and appropriate post-tests to determine significant differences between the groups. Results: There was no significant difference in mean BMI values between groups categorized by age, ethnicity or sex. Of the patients 812, 168 (21%) were classified as overweight (Group I), 546 (67%) were average BMI (Groups II-III), while 98(12%) were underweight (Group IV –V).Older children were more likely to have a higher def score (p<0.0001). There was no significant difference between mean BMI values and def score. Conclusion: There is no relationship between BMI and caries rate, however def scores are significantly higher in older children. In this study population, there was a 6% higher prevalence of overweight children compared to the children population in Texas or the United States. Failure to thrive rates within the study population and the national prevalence were similar. 5. A Novel Approach to Increase the Efficacy of Anti-Tumor Therapies
F.R. Urzua, P. Kumar, R.J. Benedict, P.J. Polverini Objectives: Radiotherapy is widely used in cancer treatment. However, treatment failures often result due to the development of radio-resistant tumor cells and endothelial cells. We have previously shown that endothelial cells are protected against radiation via activation of the phosphoinositide-3-kinase (PI3K)-Akt-Bcl-2 survival pathway. We therefore hypothesize that a combination treatment consisting of low doses of PI3K inhibitor (LY294002), cisplatin and radiation could significantly enhance the therapeutic efficacy of traditional therapies, while dramatically decreasing untoward side effects associated with the maximum tolerated doses of these anti-tumor agents. Methods: In vivo SCID Mouse Model –Human dermal microvascular endothelial cells (HDMEC 9x105) and oral squamous cell carcinoma cells (OSCC-3 1x105) were mixed with Matrigel (100µl) and injected into the hind limbs of SCID mice. Additionally, two PLF-scaffolds (HDMEC+VEGF) were implanted in the dorsal region (subcutaneously). The animals were then treated (14 days) with LY294002, cisplatin, and irradiation, either alone or in combination. Tumors and scaffolds were then removed, weighed, and measured. The samples were fixed (10%-phosphate-buffered-formalin) overnight and paraffin embedded. The tumor cells undergoing apoptosis were analyzed by in situ TUNEL staining. Immunolocalization of blood vessels – Human blood vessels in the tumors and scaffolds were immunostained using anti-human Von Wiillebrand factor and anti-human CD31 antibodies. The stained micro-vessels were counted blindly in random fields at 200x. Metamorph software was used to quantify vessel area in all samples. Results: Combination treatment significantly inhibited tumor growth in vivo (>90%), and showed significantly higher tumor cell death than those treated with single therapies. The combination treatment also significantly inhibited tumor angiogenesis (>90%), while it had significantly less effect on physiological angiogenesis (<30%). Conclusion: The combination of low doses of LY294002 and cisplatin significantly enhanced the therapeutic efficacy of radiation therapy by targeting tumor blood vessels. These results suggest a novel approach to increase the therapeutic efficacy of current anticancer therapies while decreasing negative side effects. 6. Key Determinants of Dental Care Access in an Hispanic Community
J. Farias, B.S., R. Espinoza, B.A., J. Moreno, B.S. UCLA School of Dentistry, Post-Baccalaureate Program There are disparities in access to oral health services between ethnic minority groups and the general population. Using data from 586 respondents to the Community Engagement Process Survey conducted in Pacoima, California in 2001, we analyzed determinants of access to dental care among Hispanics in this community. Following Andersen's Behavioral Model of Health Services, we examined the effects of predisposing, enabling, and need variables using bivariate and logistic regression analyses executed by the STATA 6 program. Using accesses to care as the dependent variable we conducted bivariate analyses and found that citizenship, ability to speak English, education, and unmet need were statistically significant variables. However, when we conducted a multivariate analyses, taking all factor into consideration, only usual source of care and dental insurance remained statistical significant at the P< 0.05 level in determining access. Thus, being able to identify a dental provider and also having dental insurance are key variables for Hispanics in this community in determining access to dental care. This study was funded by: Los Angeles Urban Funders, California Endowment-Community Oral Health Initiative: Partners, Programs, Pipeline, and the International Center for Dental Health Policy, UCLA School of Dentistry 7. The Integration of a Smoking Cessation Program with Initial Phase Hygiene Therapy to Control Periodontal Disease
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9. Spanish Class for Dental Personnel (Student service initiative)
A. Names of Student Project Directors: Brandon Wright (Spanish Class Coordinator) Richard Bauman (University of Kentucky HDA President) B. Contact Information via Richard Bauman: Phone: 859 797 3174 Fax: 859 257 5550 Address: 4241 Steamboat Rd. Lexington, Kentucky 40514 C. Abstract for the Project/Program: This project has been designed to provide the dental team with knowledge of basic Spanish grammar and dental related phrases. Open to all College of Dentistry faculty, staff and students. The course consists of 15 thirty-minute sessions per semester, which are taught by a bilingual student dentist. Since the Hispanic population has increased by 13% in Kentucky in the past year, the student dentist population identified a definite need. Drawing on their own resources, with minimal assistance from the College and using their own extracurricular time, the students developed and implemented a Spanish course for dental personnel. D. Importance of this Project/Program: This project allows the dental team to communicate independently with the Hispanic patient. Student dentists also teach this project as part of the University of Kentucky HDA chapter. The classes are open to the whole dental school. 10. UPRSD Hispanic Center of Excellence Focused on Health Disparities
K. Crespo, J. Torres. School of Dentistry, Medical Sciences Campus, University of Puerto Rico. The goal of the UPRSD Hispanic Center of Excellence Focused on Health Disparities is to improve Hispanic students’ performance and train Hispanic faculty in innovative instructional methodologies and research methods. It will be accomplished through activities that promote critical thinking, individualized learning and cultural competence. It also aims to improve the competitive applicant pool with a special emphasis on students from disadvantaged backgrounds and from health professional shortage areas. The objectives of the COE during the three year period aim to: 1) increase students’ passing rates and scores on the NBDE, Parts I&II; 2) train faculty in the use of innovative instructional strategies and the development of culturally sensitive multimedia instructional materials; 3) develop standardized patient’s blueprints, a bank of cases, interactive computerized instructional material, a Hispanic oral health research issues web site and a community experience in disadvantaged communities around the Island; 4) expand the UPRSD student Summer Research Internship Program and train faculty through collaborative research; 5) expand the Externship program through an additional clinical experience in an underserved community to provide services to the elderly population; and 6) increase the competitive applicant pool through a linkage with the HCOP based in San Germán Campus of the Interamerican University, the Medicine Clubs of the School of Medicine’s HCOE and the Kids in Health Careers Program of the HRSA funded Pediatric Dentistry Training Program. In the long run the project will help reduce oral health disparities in Hispanic populations. 11. Health Careers Summer Academy
Carlos Garza-Gongora The State University of New York at Buffalo, School of Dental Medicine The State University of New York at Buffalo, School of Dental Medicine and the Erie Niagara AHEC (Health Area Education Center) joined forces this summer to enlighten and motivate ambitious underrepresented students who are interested in learning more about opportunities in the health care fields. During the Health Careers Summer Academy at UB, the students are introduced to Nursing, Dentistry, Medicine & Biomedical Sciences, Public Health, Social Work and Pharmacy. Included in the student activities were case presentations involving the many disciplines in dentistry and a tour of the research facilities on campus. The hands on exercises included alginate impressions and restoring typodont teeth with amalgam and resin. The closing event was a dental based Jeopardy game in which the students could apply what they had learned during their visit to the Dental School. The AHEC program was a huge success based on the students’ and counselor’s feedback. The AHEC counselors were extremely impressed with the day’s events and expressed interest in repeating the experience with new students next year. The real success of the program came from hearing that a few of the students were interested and motivated to pursue a career in healthcare. More programs like the Health Careers Summer Academy are essential in introducing different avenues in healthcare to students who are not normally exposed to these fields. AHEC is a locally directed, federal and state supported program that was established to improve healthcare by establishing partnerships with institutions that train health professionals and the communities that need them the most. Its goal is to address the unequal distribution of the healthcare work force in the underserved communities. 12. Comparison of the Time Elapsed since most Recent Visit to Dentist and Physician in the Hispanic Population
Trujillo MI, Roldan R, Abadeer LM Objective: Parents may be prioritizing the general health of their children over the oral health of their children. Children see physicians an average of 9 to 10 times during their first year. However, there is a significant number of children that do not see a dentist until after the age of 3, if even then. This seems to be the case even though the current recommendation is that the first dental visit occurs by one year of age. Several studies suggest a relationship between oral health and general health evidenced by several facts. 1.) Many systemic diseases and conditions have oral manifestations. 2.) The oral cavity is a portal of entry as well as the site of disease for microbial infections that affect general health status. 3.) The oral cavity and its functions can be adversely affected by many pharmaceuticals and other therapies commonly used in treating systemic conditions. 4.) Individuals such as immunocompromised and hospitalized patients are at greater risk for general morbidity due to oral infections. 5.) Some studies also show the relationship between periodontal disease and diabetes, cardiovascular disease and stroke. There exists a close relationship between oral health and general health. Therefore the purpose of this study is to compare the priority that Hispanic families confer to medical care versus dental care, based on the time elapsed since last contact with a physician and the dentist respectively in children under eighteen years of age in the U.S. Methods: The publication “Summary Health Statistics for U.S. Children: National Health Interview Survey, 2002,” by the United States Department of Health and Human Services, Centers for Disease Control and Prevention, contains national data regarding health care for children under eighteen years of age. From the results of this survey, we extracted data that were very specific in scope. These data focused on the time elapsed since the most previous contact with a medical professional and the time elapsed since the most previous contact with a dental professional. We compared variables such as ethnic origin, family structure, region, family income, parent’s education, and health insurance coverage. Results: Sixty eight percent Hispanic children had a more recent contact (within the last 6 months) with the physician while 43% visited the dentist.( P <.0001)Families headed by both parents had more recent contact with a general health care provider and dentist compared to all other types of families (mother-only, father-only, and only legal guardian). The higher the education level of the parent(s), the higher the higher the percentage of children with the more recent contact with physicians and dentists. Eighty percent Children with Medicaid have had more recent contact with a health care provider than any other group (52% not insured, 77% privately insured). However, children that are privately insured visited the dentist more recently (64%) than any of the others (30% uninsured, 46% Medicaid). Regionally, the Northeast region of the United States had a most recent contact in both general health and dental care than the other regions in the United States (P< .0001). Conclusion: According to this survey, there is a disparity in the utilization of dental care vs. general health care in Hispanic children less than eighteen years of age in the United States. The data suggest that Hispanic families prioritized the general health care over dental health care based on their contact with those professionals. 13. Key Determinants of Dental Care Access in an Hispanic Community
J. Farias, B.S., R. Espinoza, B.A., J. Moreno, B.S. UCLA School of Dentistry, Post-Baccalaureate Program There are disparities in access to oral health services between ethnic minority groups and the general population. Using data from 586 respondents to the Community Engagement Process Survey conducted in Pacoima, California in 2001, we analyzed determinants of access to dental care among Hispanics in this community. Following Andersen's Behavioral Model of Health Services, we examined the effects of predisposing, enabling, and need variables using bivariate and logistic regression analyses executed by the STATA 6 program. Using accesses to care as the dependent variable we conducted bivariate analyses and found that citizenship, ability to speak English, education, and unmet need were statistically significant variables. However, when we conducted a multivariate analyses, taking all factor into consideration, only usual source of care and dental insurance remained statistical significant at the P< 0.05 level in determining access. Thus, being able to identify a dental provider and also having dental insurance are key variables for Hispanics in this community in determining access to dental care. This study was funded by: Los Angeles Urban Funders, California Endowment-Community Oral Health Initiative: Partners, Programs, Pipeline, and the International Center for Dental Health Policy, UCLA School of Dentistry 14. A Novel Approach to Increase the Efficacy of Anti-Tumor Therapies
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