JDE
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Dent Educ. 68(8): 819-822 2004
© 2004 American Dental Education Association
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Behnke, A. R.
Right arrow Articles by Hassell, T. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Behnke, A. R.
Right arrow Articles by Hassell, T. M.

Critical Issues in Dental Education: Genetics Education for Dental Health Professionals

Need for Genetics Education in U.S. Dental and Dental Hygiene Programs

Alisa Rose Behnke, S.D.H.; Thomas M. Hassell, D.D.S., Dr.med.dent., Ph.D.

Key words: genetics, genetics education, dental schools survey, dental hygiene programs survey

Submitted for publication 02/11/04; accepted 05/28/04


   Abstract
Top
 Abstract
Methods
 Results
 Discussion
 References
 
The two major afflictions of the oral cavity are dental caries and gingival/periodontal disease. While microorganisms have long been acknowledged as important etiologic factors, the most recent research data demonstrate that both of these pathologic conditions have a strong shereditary base, i.e., even in the presence of putative pathogenic microorganisms, if the host individual is not genetically susceptible, ensuing disease will be mild or even nonexistent. In the face of this evidence for heritability of the two major oral diseases, we evaluated what educational experiences in genetics were provided to students in U.S. dental schools and dental hygiene programs in 2003–04. Our survey of fifty-four dental schools revealed that only one requires a formal genetics course before admission, and only six incorporate a required genetics course within the dental curriculum. Of the 264 dental hygiene programs surveyed, none require a formal genetics course as a prerequisite for admission, and none require a formal genetics course within their curricula. The enormous successes, and future promise, of the Human Genome Project suggest that genetics will soon dominate the future of medicine and dentistry, in prediction of diseases, disease diagnosis, and, eventually, therapy for genetically based disorders. It is therefore incumbent upon dental and dental hygiene education programs to provide genetics education for tomorrow’s practitioners.

Throughout generations, it has been casually noticed that "dental diseases seem to run in families." Non-scientific reports were common in the early 1900s; for example, consider these anecdotal observations cited in Hassell and Harris1: "Inheritance plays a massive role in periodontitis. I once saw a mother of eight who had periodontal disease, and so did four of her children"; "We can detect no environmental factor to explain the differences in caries susceptibility between caries-prone and caries-free individuals/parents/siblings. We conclude that genetic factors play an appreciable part in determining individual resistance against dental caries."

Beyond these anecdotal observations, the question of a possible true genetic predisposition toward dental caries was studied in earnest in the first half of the twentieth century by several reputable investigators.2–4 In an elegant animal model system, Hunt and Hoppert demonstrated in 1944 that dental caries susceptibility is a heritable trait.5 Klein, in his 1946 study of DMFT in 5,400 individuals from 1,150 different families, concluded that "dental disease in children involves strong familial vectors (sic) which . . . have a genetic basis."6 Comprehensive reviews of the research on heritability of caries were published in 19637 and 1972.8 In 1988, a landmark study was published by Boraas et al.9 Their six-year retrospective study of a large cohort of fraternal and identical adult twins demonstrated that almost 90 percent of dental parameters investigated were associated with highly significant within-pair resemblance in the identical twins, thus providing new and convincing evidence for a significant genetic component in dental caries experience.

The genetic basis of inflammatory periodontal disorders was less established until quite recently, primarily due to the relative complexity of the disease, continually emerging new knowledge about its pathogenesis, vagueness of clinical diagnosis and statistical quantitation, and the profession’s own nomenclature for classifying these diseases, which continues to evolve.10 During the 1950s, Baer et al. performed an exhaustive series of mouse breeding experiments, using strains that were highly susceptible to alveolar bone loss and other strains that were quite resistant, and concluded that these strains differed at several genetic loci, each of which exerted an effect on periodontal disease susceptibility.11–13

In the 1990s, the periodontal research group at the University of Minnesota14–18 used the large Minnesota Twins Registry19 to conduct a series of studies to define the magnitude of hereditary control over periodontal disease susceptibility. Their initial reports indicated that up to 80 percent of the population variances in gingival and periodontal clinical indices could be accounted for by hereditary factors. In a more recent study of another large human twin cohort,20 hereditary factors accounted for approximately 50 percent of "adult periodontitis," still a dramatic genetic effect. Similar findings were reported by other investigators.21 In 2000, Michalowicz et al. concluded that "the basis for the heritability of periodontitis appears to be biological and not behavioral in nature."20 Excellent reviews of the influences of genetics in periodontal diseases have appeared recently.1,22,23

Deciphering the mechanisms of such genetic control is difficult. Recent clinical and laboratory investigations have shed light on some mechanisms and spurred increased interest in identifying genetic risk factors for adult periodontitis. Clinical disease incidence and severity have been found to be associated with gene polymorphisms in interleukin (IL)-1a and IL-1b,24–26 IgG Fcg receptor,27,28 and HLA loci.29 In vitro studies using gingival fibroblasts from human twins have demonstrated that the cellular proliferation rate is genetically regulated.30 Further, responses of periodontal connective tissue cells to the metabolic products of pathogenic oral bacteria have been shown to be under genetic control.31

The successes of the Human Genome Project (HGP)32 promise to solidify genetics as the new cornerstone of medicine and dentistry now and into the future. Enormous strides have already been made in using genomic research to predict disease occurrence (e.g., breast cancer, myocardial infarction, periodontitis, melanoma, Alzheimer’s disease, diabetes). With current research targeting new ways to intercept disease processes before they start, "pharmacogenetic" approaches to heritable disorders systemically and in the oral cavity may be implemented in the future.

New knowledge emerging from the HGP is creating an educational dental/medical paradigm shift. Therefore, we wished to ascertain the current state of genetics education in U.S. dental schools and dental hygiene programs.


   Methods
Top
 Abstract
 Methods
Results
 Discussion
 References
 
This survey was conducted during December 2003 and January 2004, at which time there were fifty-six U.S. dental schools. Two of these had only recently opened and were not surveyed. There are 264 U.S. dental hygiene education and training programs.

Our approach was twofold. First, we used the Internet to access curricular components of all 318 D.D.S. and R.D.H. programs from their websites. Then, after examining and collating all information from the websites, telephone interviews were conducted with either the director of admissions or the chair of the curriculum committee at the U.S. dental schools to confirm our initial assessments from the web data. Similar telephone interviews were conducted with appropriate administrative individuals at 185 of the 264 dental hygiene programs. These 185 programs were chosen for telephone interviews because of inconsistencies, vagueness, or omissions in their web-based curricular listings.

Our approach was the same in each telephone interview. We sought answers to three basic questions:


   Results
Top
 Abstract
 Methods
 Results
Discussion
 References
 
Of the 264 dental hygiene programs in the United States, not one currently requires a genetics course for entry into the program, and not one has a required genetics course within the professional curriculum itself. Several programs reported that they "suggested" to applicants that a genetics course would be valuable or otherwise "helpful" for entry into the program.

Of the fifty-four dental schools in the United States that we surveyed via website and telephone interview, only one (University of Florida College of Dentistry, Gainesville, FL) currently requires a genetics course before entry into the program of study. As of December 2003, the core curricula of the following six U.S. dental schools contain a formal, required course in genetics:

Four of the genetics courses required in U.S. dental schools are taught by faculty members from collocated medical schools, with, in some cases, guest lectures by dental school faculty members. Two courses are taught by dental school faculty members.


   Discussion
Top
 Abstract
 Methods
 Results
 Discussion
References
 
Clearly, U.S. dental and dental hygiene programs are already far behind in terms of educating tomorrow’s practitioners in genetics and its implications on clinical practice.

Our survey results need not necessarily be viewed as critical of those schools and programs not currently requiring formal genetics education because it is possible, and likely, that some aspects of genetics are included in other courses such as developmental biology, pathology, or molecular biology. Our survey did not address these possibilities, but Dudlicek et al.33 reported in detail about this aspect of dental education (but not dental hygiene education). Further, Dudlicek et al. report survey data that were collected in 2001, while our study was conducted during the 2003–04 academic year. Dudlicek et al. report that eight dental schools require a formal genetics course, while our survey found only six. We have ascertained now that two dental schools dropped their genetics requirement since 2001. This finding demonstrates that few U.S. dental schools are emphasizing genetics in their curricula in a formal manner; indeed, the trend appears to be toward reducing courses in genetics.

In summary, genetics is the future of dentistry and medicine. Institutions offering professional health care education in the United States must quickly come to accept this fact and move to incorporate formal study of genetics, and its implications, into the prerequisite array of coursework and into the body of study within professional education. In 1997, even three years before the DNA code was finally deciphered, the scientific director of the Human Genome Project, Dr. Francis Collins, published a prescient paper in the Journal of the American Medical Association entitled "Preparing Health Professionals for the Genetic Revolution."34 A Journal of Dental Education article by former NIDCR Director Slavkin in 200135 implored educators to access and evaluate the recommendations put forth by a Blue Ribbon Panel on the Future of Education and Training in Dental and Craniofacial Sciences (see www/nidcr.nih.gov). Both Collins and Slavkin advocated increased curricular emphasis on genetics education. In the words of Slavkin, "change" and "revision" are the operative terms for the coming decades of the twenty-first century.


   Footnotes
 
Ms. Behnke is a dental hygiene student in the baccalaureate program and Dr. Hassell is Professor of Dental Hygiene in the College of Health Professions, Northern Arizona University. Direct correspondence and requests for reprints to Dr. Thomas M. Hassell, Northern Arizona University, P.O. Box 15065, Flagstaff, AZ 86011-5065; 928-853-8387 phone; 928-523-6195 fax; thomas.hassell{at}nau.edu


   REFERENCES
Top
 Abstract
 Methods
 Results
 Discussion
 References
 

  1. Hassell TM, Harris EL. Genetic influences in caries and periodontal diseases. Crit Rev Oral Biol Med 1995;6: 319–42.[Abstract]
  2. Siemens H, Hunold X. Zwillingspathologie: Untersuchungen der Mundhöle [Twins pathology: examinations of the oral cavity]. Arch Derm Syph 1924;147:409–23.
  3. Dahlberg G, Dahlberg B. Ueber Karies und andere Zahnverönderungen bei Zwillingen [On caries and other dental disorders in twins]. Uppsala Lakför Förl 1942;47:395–416.
  4. Mansbridge B. Heredity and dental caries. J Dent Res 1959;38:337–47.[Free Full Text]
  5. Hunt H, Hoppert C. Inheritance of susceptibility to caries in albino rats. J Dent Res 1944;23:385–401.[Abstract/Free Full Text]
  6. Klein H. The family and dental disease. IV. Dental disease (DMF) experience in parents and offspring. J Am Dent Assoc 1946;33:735–43.
  7. Finn S, Caldwell R. Dental caries in twins. I. A comparison of the caries experience of monozygotic twins, dizygotic twins, and unrelated children. Arch Oral Biol 1963;8:571–85.
  8. Zengo A, Mandel I. Sucrose tasting and dental caries in man. Arch Oral Biol 1972;17:605–7.[Medline]
  9. Boraas IC, Messer LB, Till M. A genetic contribution to dental caries, occlusion, and morphology as demonstrated by twins raised apart. J Dent Res 1988;57:1150–5.
  10. Ranney R. Classification of periodontal diseases. Periodontol 2000 1993;2:13–25.
  11. Baer P, Lieberman I. Observations on some genetic characteristics of the periodontium in three strains of inbred mice. Oral Surg Oral Med Oral Pathol 1959;12:820–9.[Medline]
  12. Baer P, Lieberman I. Periodontal disease in six strains of inbred mice. J Dent Res 1960;39:215–25.[Free Full Text]
  13. Baer P, Crittenden D, Jay GE Jr, Lieberman I. Studies on periodontal disease in the mouse. II. Genetic and maternal effects. J Dent Res 1961;40:23–33.[Free Full Text]
  14. Michalowicz B, Aeppli D, Kuba RB, Bereuter IE, Conry JP, Segal NL, et al. A twin study of genetic variation in proportional radiographic alveolar bone height. J Dent Res 1991a;70:1431–5.[Abstract/Free Full Text]
  15. Michalowicz B, Aeppli DP, Virag JG, Klump DG, Hinrichs JE, Segal NL, et al. Periodontal findings in adult twins. J Periodontol 1991b;62:293–9.[Medline]
  16. Michalowicz B. Use of twin models to estimate genetic influence on periodontitis. J Dent Res 1992;71:165 (abs).
  17. Michalowicz B. Genetics and inheritance considerations in periodontal disease. Curr Opin Periodontol 1993; 11–17.
  18. Michalowicz B. Genetic and heritable risk factors in periodontal disease. J Periodontol 1994;65:479–88.[Medline]
  19. Bouchard T. Twins reared together and apart: what they tell us about human diversity. In: Fox SW, ed. Individuality and determinism: chemical and biological bases. New York: Plenum Publishers, 1984:147–78.
  20. Michalowicz B, Diehl S, Gunsolley J, Sparks B, Brooks C, Koertge T, et al. Evidence of a substantial genetic basis for risk of adult periodontitis. J Periodontol 2000;71:1699–707.[Medline]
  21. Corey I, Nance W, Hofstede P, Schenkein H. Self-reported periodontal disease in a Virginia twin population. J Periodontol 1993;64:1205–08.[Medline]
  22. Hart T. Genetic risk factors for early-onset periodontitis. J Periodontol 1996;67:355–66.
  23. Hart T, Kornman K. Genetic factors in the pathogenesis of periodontitis. Periodontol 2000 1997;14:202–15.
  24. Diehl SR, Wang Y, Brooks CN, et al. Linkage disequilibrium of interleukin-1 genetic polymorphisms with early-onset periodontitis. J Periodontol 1999;70:418–30.[Medline]
  25. Kornman KS, Crane A, Wang HY, et al. The interleukin-1 genotype as a severity factor in adult periodontal disease. J Clin Periodontol 1997;24:72–7.[Medline]
  26. Gore EA, Sanders JJ, Pandey JP, Palesch Y, Galbraith GM. Interleukin-1 beta+3953 allele 2: association with disease status in adult periodontitis. J Clin Periodontol 1998;25:781–5.[Medline]
  27. Kobayashi T, Westerdaal NA, Miyazaki A, et al. Relevance of immunoglobulin G Fc receptor polymorphism to recurrence of adult periodontitis in Japanese patients. Infect Immun 1997;65:3556–60.[Abstract]
  28. Kobayashi T, Sugita N, Ludo van der Pol W, Nunokawa Y, Westerdaal N, Yamamoto K, et al. The Fc{gamma} receptor genotype as a risk factor for generalized early-onset periodontitis in Japanese patients. J Periodontol 2000;71: 1425–32.[Medline]
  29. Bonfil JJ, Dillier FL, Mercier P, et al. A "case control" study on the role of HLA DR4 in severe periodontitis and rapidly progressive periodontitis: identification of types and subtypes using molecular biology (PCR.SSO). J Clin Periodontol 1999;26:77–84.[Medline]
  30. Cockey G, Boughman J, Harris E, Hassell T. Genetic control of variation in human gingival fibroblast proliferation. In Vitro Cell Dev Biol 1989;25:253–8.
  31. Hassell T, Baehni P, Harris E, Walker C, Gabbiani G, Geinoz A. Evidence for genetic control of changes in factin polymerization caused by microorganisms: in vitro assessment using gingival fibroblasts from human twins. J Periodontal Res 1997;32:90–8.[Medline]
  32. Golden F, Lemonick M. The race is over. Time, July 3, 2000:19–23.
  33. Dudlicek L, Gettig E, Etzel K, Hart T. Status of genetics education in U.S. dental schools. J Dent Educ 2004;68(8):809–18.[Abstract/Free Full Text]
  34. Collins F. Preparing health professionals for the genetic revolution. JAMA 1997;278:1285–6.[Medline]
  35. Slavkin H. The human genome, implications for oral health and disease, and dental education. J Dent Educ 2001;65:463–79.[Abstract]



This article has been cited by other articles:


Home page
 J Dent EducHome page
A. M. Iacopino
The Influence of "New Science" on Dental Education: Current Concepts, Trends, and Models for the Future
J Dent Educ., April 1, 2007; 71(4): 450 - 462.
[Abstract] [Full Text] [PDF]

Home page
 Journal of the American Dental AssociationHome page
S. R. Diehl
Pulling teeth into the genomics era.
J Am Dent Assoc, June 1, 2006; 137(6): 710 - 716.
[Full Text] [PDF]

Home page
 J Dent EducHome page
F. Collins and L. Tabak
A Call for Increased Education in Genetics for Dental Health Professionals
J Dent Educ., August 1, 2004; 68(8): 807 - 808.
[Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Behnke, A. R.
Right arrow Articles by Hassell, T. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Behnke, A. R.
Right arrow Articles by Hassell, T. M.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS