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THE PAST AND PRESENT AS PROLOGUE
DIVERSITY OF DISEASES AND PATIENTS
TRANSFORMING TREATMENTS
TRANSFORMING HEALTH PROFESSIONAL EDUCATION
TRANSFORMING HEALTH CARE
ORAL HEALTH — NOT YET FOR ALL
HOPE FROM SCIENCE AND TECHNOLOGY
A FRAMEWORK FOR ORAL HEALTH
REFERENCES |
The challenges for oral health in the twenty-first century are formidable. First and foremost is the need to ensure that all people have access to health care and can acquire the health literacy necessary to make use of health promotion and disease prevention information and activities.
The century offers the promise of a new era for health wrought by the convergence of six cultural movements, any one of which would be sufficient to transform the human condition:
- The biological and biotechnology revolutions.
- A redistribution of the world’s people by rapid and sizable migrations within countries and across borders.
- Changing demographics in industrialized as well as developing nations.
- Changing patterns of disease, including the emergence and reemergence of infectious diseases, and changes in the organization of health care.
- Instant worldwide communication through the Internet, cable, satellite, and wireless technology.
- A continuing exponential rate of growth in information technology, specifically in computer speed, memory, and complexity.
These global currents are changing the way we live now and will have profound implications for the future of the oral and general health and well-being of all people.
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THE PAST AND PRESENT AS PROLOGUE
The Pioneers
The history and intellectual activity of the eighteenth and nineteenth centuries set the seeds for the flowering of biology in the twentieth and early twenty-first centuries (Porter 1997). The scientific and technological discoveries of the early anatomists and embryologists—the founders of cell theory and brain research—were followed by the brilliant innovations of Pasteur, Koch, and Ehrlich, who established the new fields of microbiology and immunology. The cumulative achievements of these pioneers set the foundation for the diagnostic and therapeutic science and art of dentistry, medicine, nursing, and pharmacology in the twentieth century.
The seeds were also sown for the convergence of chemistry, physics, and biology in the field of molecular biology, as well as the convergence of Darwinism, fruit fly genetics, and population genetics into the modern evolutionary synthesis. These convergences inspired the current quest to identify all 100,000 genes of the human genome and to assign functional meanings to the motifs that are encoded within them.
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Vital Statistics
The growth of the world population and the transcontinental movements of people are proving a dominant force for change. The twentieth century began with increased European and Asian migrations to the United States. By 1900 the U.S. population had reached 90 million residents and the Earth’s population was approaching 1 billion people. Life expectancy in the United States was 47 years of age. Acute viral and bacterial infections were the primary causes of infant morbidity and mortality. Being edentulous, or “toothless,” was a normal expectation for mature adults.
For most of recorded human history and the 100,000 years of human prehistory, life expectancy was very low. Life expectancy at the time of the Roman Empire was approximately 28 years of age. From the beginning of the first millennium A.D. to 1900, each year of history saw an average gain of 3 days in life expectancy. Each year since 1900, however, has seen a gain of 110 days in average life expectancy (Rowe and Kahn 1998). Life expectancy at birth in the United States has increased from 47 years in 1900 to approximately 76 years today. While the entire population of the United States has tripled since 1900, the absolute number of older persons, currently 33 million, has increased elevenfold (Finch and Pike 1996, Rowe and Kahn 1998, p. 4). The U.S. population is 270 million and will reach 300 million in the next few decades. The Earth’s population doubled by 1950, doubled again by 1975, and currently is 6 billion.
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Health Improvement
Measures such as improved sanitation and housing, prenatal care, immunizations, health education and promotion, community water fluoridation, and dental sealants have greatly improved oral health for the majority of the population. Advances in science and technology, health professional education, the science of public health and clinical practice, and the health literacy of the public will continue to improve the health and well-being of Americans in the coming years (Kevles 1997, Schwartz 1998). Ever larger numbers of senior adults expect to retain a full or nearly complete dentition and to live well into their 70s, 80s, and 90s free of pain and discomfort (Slavkin 1997a).
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DIVERSITY OF DISEASES AND PATIENTS
Those seeking care in the decades ahead will present with a wide range of diseases and disorders, unevenly distributed across populations. The very youngest patients include children with complex hereditary or congenital craniofacial defects in need of expert multidisciplinary teams to repair and restore form and function. Early childhood caries, one of the most severe forms of the disease, is especially prevalent among poor children in some racial/ethnic groups in America, such as American Indians and Mexican Americans. Young adults are particularly vulnerable to unintentional and intentional craniofacial injuries. Middle-aged and older generations typically experience chronic diseases affecting the heart or lungs as well as cancers, diabetes, and the various degenerative diseases of joints and bones and the nervous system, all of which may affect or be affected by oral diseases and their treatments.
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TRANSFORMING TREATMENTS
The cultural movements that are changing the human condition will likely transform treatments for many of the complex disorders just described. The instrumentation used to detect subtle genetic variations in each of the 100,000 genes in the human genome will inexorably reveal which gene or genes are defective in hundreds of inherited and acquired craniofacial diseases or syndromes. On the horizon are promotion measures to enhance health and eliminate exposures to teratogens, as well as surgical techniques to correct the defects in utero, obviating the need for costly multiple surgeries and rehabilitation programs for affected children.
We are entering the “golden age of molecular oral health” with gene-based diagnostics, therapeutics, and biomaterials. Risk assessment for disease will be based in part on understanding the genetic variations that affect resistance or susceptibility, but also will be determined in part by environmental factors, socioeconomic status, personal behaviors, and lifestyle. The risk for early childhood caries is likely to be determined by a combination of all these factors, as well as cultural beliefs and practices within some populations. Elimination of all infections, whether in the oral cavity or elsewhere, will be seen as a critical part of health promotion.
Prevention of injuries will call for approaches that are both culturally and age sensitive, in addition to the coordinated efforts of policymakers and legislators to mandate protective gear in sports and other safety measures when necessary.
Gene therapy will be applied to treat oral and pharyngeal cancers and also will be used for the oral and systemic delivery of endogenous and synthetic molecules to treat salivary gland disorders, oral infections, and systemic disease. Highly specific drugs will be developed for the management of chronic facial pain such as trigeminal neuralgia and Bell’s palsy.
Should additional evidence in the early years of the twenty-first century further indicate that oral infections actually cause some cases of heart disease, pulmonary disease, and stroke, or trigger the birth of premature, low-birth-weight babies, treatment approaches will be radically altered.
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TRANSFORMING HEALTH PROFESSIONAL EDUCATION
The scientific and technological bases of dentistry, medicine, nursing, and pharmacy are expanding rapidly in parallel with the changing demographics of the nation, the public’s expectations for an enhanced quality of life, and changes in the management and financing of health care. Health professional schools, often organized around academic health science centers, are responding to these challenges and opportunities.
Students and clinicians alike need to be prepared to adopt evidence-based health care. Today and tomorrow, students must be well versed in epidemiology, biometry, bioinformatics, molecular biology, bioengineering, and much more. In addition, they must be prepared to adopt and implement new preventive strategies and comprehensive and molecular-based diagnostics and therapeutics; to support cost-effective community-based health programs; and to anticipate all the challenges that promotion of health entails. Clinical science or scientific evidence in the new millennium will continue to evolve in molecular dentistry and medicine with attendant opportunities for addressing the social, legal, and ethical implications. We must prepare clinicians for the nuances and complexities of modern clinical research-based results.
The previous chapters of this report provide the documentation that can be used to assess health professional education. Major progress in health promotion, disease prevention, diagnostics, therapy and therapeutics, and the socioeconomic and behavioral factors that influence oral, dental, and craniofacial health will further contribute to the transformation of health professional education.
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TRANSFORMING HEALTH CARE
We are currently witnessing a significant transformation in the financing and management of health care, which is affecting all the health specialties. Care providers are assuming new responsibilities and functions, and changing employment patterns. Traditionally, the management of health care has been centered on the providers of services and hospitals. Recently, the center has enlarged to include additional marketplace stakeholders, the purchasers of health care and health care plans, and increasingly all segments of society. The interactions among all these participants will shape health and health care for the foreseeable future.
Risk assessment models are also being developed and used to design treatment options tailored to communities and to individual patients. Increased use of information technology, greater efforts to conduct community needs assessments, and greater emphasis on enhanced quality of life expectations of patients, families, and communities are also in evidence (USDHHS 2000).
The responsibility for oral and craniofacial care involves all health professionals, so coordinated care delivery and reimbursement will be critical. Evidence-based systematic assessments and guidelines will contribute to clinical and public health decision making. In addition, the linkage between health care professions and public health and social service activities will need to be strengthened.
These trends are complemented by greater understanding of the psychosocial-behavioral aspects of oral diseases and disorders. These advances will continue to influence the nation’s capacity to address the breadth and depth of diseases and conditions affecting oral health across the life span and their relationship to general health and well-being.
Access to the Internet and increased health and science reporting in print and broadcast media have created a more knowledgeable public motivated to understand the value of healthy choices. However, increasing numbers of patients are also questioning traditional practices and seeking alternative and complementary approaches.
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ORAL HEALTH—NOT YET FOR ALL
Demographers predict that by 2050 there will be no single racial/ethnic majority in the United States. Rather, we will become an increasingly diverse nation with diverse patterns of disease and levels of health. This is especially evident for African American, Latino, Asian and Pacific Islander, and American Indian communities (Pamuk et al. 1998). Disparities in educational advancement, job opportunities, income and wealth, housing and neighborhood characteristics, health access and status, and involvement in the criminal justice system for various subpopulations will remain unless steps are taken to reverse the trends (Council of Economic Advisers 1998).
The proportion of school-aged children who are caries-free in their permanent teeth has more than doubled during the last 20 years. However, in states such as California, Texas, Louisiana, Alabama, Florida, and Georgia the trends are different; fewer than one third of the children are caries-free in their permanent dentition.
One attempt to come to the aid of poor children is the State Children’s Health Insurance Program (SCHIP), federal legislation designed to help individual states meet the health needs of children (Council of Economic Advisers 1998, NRC 1998). As of 1998, more than 11 million children in America—1 in 7 children—are estimated to be uninsured. Most of these children live in families with working parents who have jobs that do not provide health insurance and who are unable to purchase health care insurance (NRC 1998). Nationally, 1 in 6 African American children and 1 in 4 Hispanic children are uninsured, compared with 1 in 10 white children (Council of Economic Advisers 1998, NRC 1998). This limited health care access is particularly significant in relation to oral health.
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HOPE FROM SCIENCE AND TECHNOLOGY
The biological and biotechnology revolutions will accelerate, inspiring theory building and new models of miniaturization and speed that can be applied to improve oral health. The Human Genome Project will be completed no later than 2003. The entire human genetic lexicon will be accessible through the Internet. To date, more than several hundred mutated craniofacial regulatory and structural genes have been found to cause abnormal formation of oral, dental, and craniofacial tissues and structures.
In addition, the genomes of many significant viruses, bacteria, yeast, parasites, plants, and animals are currently being deciphered, and these are revolutionizing how we think about biology and human diseases (Bodmer and McKie 1995, Chambers 1995, Collins et al. 1998). At present, research is under way to decipher the genetic lexicon of 60 microbes, 6 of which are important oral pathogenic bacteria or fungi. The evolution of this knowledge will yield innovations in areas from clinical prevention to drug and biomaterials discovery. Figure 11.1 presents a model of the possible interface between genomics and molecular dentistry.
Perhaps with the sole exception of trauma, all human diseases have a genetic component. Genetic dentistry and medicine are based on the paradigm that changes or mutations in individual nucleotides within genes or alleles result in variations or polymorphisms. These mutations are either inherited or acquired after birth. For example, inherited mutations in the amelogenin gene located on the human X (and Y) chromosome can produce X-linked dominant or recessive amelogenesis imperfecta, a painful disease characterized by defective tooth enamel (Backman 1997), and mutations in the fibroblast growth factor receptor 2 gene can produce serious craniofacial birth defects such as Crouzon’s disease and other syndromes with premature fusion of cranial bones (craniosynostosis) (Cohen 1997). Mutations in a number of transcription factors that regulate development produce other craniofacial syndromes (Slavkin 1999).
The human genome contains approximately 100,000 genes or alleles. The genome consists of 3 billion nucleotides or bases. Mutations changing one or more bases, in one or more genes, can result in diseases or disorders. Many environmental factors termed mutagens, carcinogens, or teratogens can cause mutations in one or more genes resulting in human disease such as neoplastic diseases. The completion of the Human Genome Project in the next 2 years will afford an unprecedented opportunity to advance our understanding of inherited as well as acquired human diseases and disorders.
Scientific discoveries are rapidly defining single-gene mutations, mapping these individual genes in their precise positions on each of the 46 human chromosomes. These findings are being used to diagnose inherited and acquired clinical phenotypes as well as “at-risk populations” throughout the human life span.
These remarkable advances in human molecular genetics are identifying candidate genes for developing targeted gene-mediated therapeutic approaches to many oral health diseases, ranging from passive immunization for dental caries, induction of new bone and cartilage tissue, and regeneration of periodontal tissues, to the artificial synthesis of saliva for patients suffering from xerostomia.
Gene mutations also define the virulence of microbes (viruses, bacteria, yeasts, and parasites), as well as the fidelity of the human immune system. Microbial as well as human genes are extremely sensitive to environmental stress and can and do mutate, resulting in antibiotic resistance. The genetic variance within microbial genomes such as the genome of the yeast Candida albicans may be closely aligned with the host changes associated with immunologically compromised patients. The HIV viral genome is another particularly useful model for considering viral mutation frequency during pathogenesis (Slavkin 1996a). These discoveries provide the foundations for gene-based diagnostics for disease detection; therapeutic drug development; and individual predictors of drug response during the management of chronic facial pain, osteoarthritis as related to temporomandibular joint disease, and osteoporosis associated with periodontal diseases.
We are beginning to understand that polymorphisms (variations) in multiple genes confer susceptibility or resistance to chronic and disabling diseases and disorders such as osteoporosis, periodontal diseases, and temporomandibular disorders (Slavkin 1997b). In these examples, multiple genes and multiple gene-environment and gene-gene interactions are associated with the molecular etiology and pathophysiology of the disease process.
The function of most genes must inevitably be studied and understood at the level of their encoded proteins and protein-protein interactions, for these are the biologically active players of life. An enormous number of genes encode protein information that is highly conserved, that is, found in almost identical form in such diverse organisms as fruit flies and humans. Further scrutiny and analysis have determined that specific motifs encoded in larger domains of each protein serve as the “business” portion of the protein, binding to a cell surface, aggregating with other proteins, serving to catalyze a chemical reaction, binding to zinc or calcium ions, or serving other crucial functions in cell biology. The functional motifs are also being characterized in terms of structural biology. The scientific and educational communities are building large databases and then mining this information by using sophisticated information technology.
These genomic databases provide remarkable opportunities for the identification, design, and production of a new generation of biomarkers for diagnostics; innovative biomaterials for repair and regeneration; and the development of highly sensitive and specific drugs and vaccines to improve the health of all people (Baum et al. 1998, Slavkin 1996b,c, 1997a). Genomics has emerged as a major driver to realign academic, industry, and government science and technology to foster health, pharmaceutical, biotechnology, agricultural, food, chemical, environmental, energy, and computer science applications (Kaku 1997, Rifkin 1998). Many of these applications profoundly influence oral health (Slavkin 1996d, 1998a,b).
This epic period will also herald the advent of “biochemistry on a chip,” used in connection with body fluids such as saliva, cells, and tissues to diagnose diseases and disorders. The so-called chip technology will enable identification, quantitation, and complex analyses on surfaces no larger than one-centimeter square coupled to laser optical reader systems and computer-assisted informatics. Prototypes are already available to be tested against samples of saliva, cervical fluids, buccal mucosal cells, and blood (Slavkin 1998b). This technology should revolutionize saliva-based diagnostics and prognostics in oral health (Table 11.1). Major progress is also anticipated in bioengineering through nanotechnology, miniaturization, and the innovations of design and fabrication of biomaterials. Anticipated advances include the repair and regeneration of cartilage, bone, muscle, nerve, salivary glands and saliva, and teeth (cementum, dentin, enamel, and periodontal ligament) (Slavkin 1996d, 1998a,b).
Additional scientific progress in the neurosciences will have broad implications for the diagnosis and treatment of diseases and disorders of the craniofacial complex including neuromuscular-related conditions (e.g., facial and dental trauma, bruxism, autism, Mobius syndrome, Bell’s palsy, temporomandibular joint disorders, trigeminal neuralgia, Parkinson’s disease, and disorders of speech, smell, and taste), the habilitation of craniofacial syndromes, and the management of facial pain.
The field of biomimetics is an example of the translation of human genomics into innovative developments in biotechnology. The idea is to use biological strategies to solve human diseases and disorders, essentially mimicking biological processes in the design and fabrication of new biomaterials to replace body parts or synthesize new drugs or reagents. For example, biological cartilage can now be designed and produced in artificial systems that present three-dimensional forms for nose and ear replacements as required in craniofacial birth defects, head and neck trauma, and oral and pharyngeal cancer patients (Slavkin 1996b, 1998a,b). Another approach is to design and fabricate bioceramics to be used in the replacement of human enamel or dentin on the surfaces of teeth.
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A FRAMEWORK FOR ORAL HEALTH
At the most basic level, local, state, and national health care policies will continue to strive to improve the health status of all Americans. Major reforms will improve public health competency. Enlightened health literacy will continue to influence quality of life expectations. Many social, economic, and political influences will continue to influence local, state, and national priorities for health policies (Isaacs and Knickman 1999). Included in these reforms will be efforts to improve the oral and craniofacial health of the American people.
Oral and craniofacial health issues will continue to be diverse and complex. In this context, two major themes remain: the need and demand for oral and craniofacial health services; and the role, functions, and mix of health professionals (Casamassimo 1996, USDHHS 1998).
First, need and demand will continue to be the two drivers of the health service requirements of our society. Need is an epidemiologically based and clinically derived measure of the amount of disease and adverse conditions that require treatment in order for the population to be healthy. Demand measures a population’s health literacy, willingness, and capacity to utilize and finance health services. Public health literacy or competency and proactive oral health education will increase demand as well as delineate functions of oral health professionals for 2000 and beyond. Often, biomedical research advances in terms of new pharmaceuticals, devices, and procedures popularized in the media influence quality of life expectations, demand for health services, and the economy (Pardes et al. 1999). They can also lead to the creation of new types of health providers. Research also has the potential to reduce the need, demand, and costs for health services (McRae 1994). Thus outpatient surgery obviates the need for hospitalization; immunization or antibiotics control infections; and community water fluoridation, other fluorides, dental sealants, and related oral health policies help prevent dental caries.
Second, the major changes in demography, patterns of disease, and management of health care will continue to shape the roles and functions of health professionals. For example, significant increases in the numbers of senior citizens (65 years and older) with chronic facial pain, osteoarthritis, temporomandibular joint disorders, type 2 diabetes, dementia, osteoporosis, and oral and pharyngeal cancers will challenge health care providers for the next 50 years. These conditions will necessitate interdisciplinary and multidisciplinary approaches to care. Coordination of professional care with that of individuals, caregivers, and the community will be needed to control costs and ensure early diagnosis and prompt treatment.
To ensure that all people have access to health care and can acquire the health literacy necessary to make use of oral and craniofacial health promotion and disease prevention information and activities, a complete assessment of the nation’s capacity to achieve access for all is warranted. Federal, state, and local government programs, legislation, and regulation; health professional societies and organizations; professional schools, colleges within universities, and K-12 education; patient groups; the private sector; and the larger society have the responsibility to achieve access to oral health care for all.
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