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"I completed my cancer
therapy for breast cancer (surgery, radiation and
chemotherapy) and now my chief complaint is that I can not
produce saliva, and my dentist and physician note that I
present rampant tooth decay. My health insurance covered all
of my cancer therapies but does not cover my oral health
needs. Why?" This simple and poignant statement from one
of the 1.4 million cancer therapy patients each year raises a
number of significant issues. Are national, state and private
industry health policies considering the mouth as part of the
body? Why do we segregate medical, dental, mental and vision
health care? Is this not a time for integrated and
comprehensive health promotion, risk assessment, disease
prevention, diagnostics, treatments and therapeutics?
These questions herald new
opportunities as many of us consider academic professional
health education, patient care, research and health policies
in the 21st century. Is there a mouth-body connection? If
"yes," can we increase collaborations with other
colleges at USC? The nation? The world? The scientific
literature indicates that osteoarthritis, osteoporosis, oral
and pharyngeal cancer, AIDS, Parkinson's disease and
periodontal diseases each represent striking examples of
"the mouth-body connection." Many other systemic
chronic diseases and disorders such as diabetes, chronic
fatigue syndrome, fibromyalgia, pulmonary diseases, and a
number of autoimmune diseases, such as Sjogren's syndrome,
directly or indirectly compromise health and well-being.
The recent Surgeon General's
Report Oral Health in America (2000) provided a vast amount of
science-based information related to these and other
craniofacial-oral-dental diseases and disorders. This SG
Report further presented the significant progress that has
been made in reducing the extent and severity of common oral
diseases in most people through a variety of preventive
measures. However, not everyone is experiencing the same
degree of improvement or resistance to oral diseases and
disorders. Approximately 46 million Americans do not have
medical insurance, and 110 million do not have dental
insurance. Access to quality and comprehensive health care is
a major and recalcitrant problem in America! Have you read the
SG Report?
The mouth is a portal of entry,
and it is a mirror that reflects a wealth of information that
can be derived from oral fluids and tissues. The mouth
includes not only the teeth and the gums and their supporting
connective tissues, ligaments, and bone; but also the hard and
soft palate, the mucosal lining of the mouth and throat, the
tongue, the lips, the salivary glands, the oral fluid saliva,
the muscles of mastication, and the upper and lower jaws,
which are connected to the skull by the two temporomandibular
joints. The branches of the nervous, immune and vascular
systems animate, protect and nourish the oral tissues, as well
as provide
connectivity with the brain and the rest of the body. The term
craniofacial-oral-dental complex captures these anatomical and
physiological relationships.
As the gateway to the body, a
constant barrage of invaders - viruses, bacteria, parasites,
and fungi - challenges the mouth. Transmissible infectious
diseases, notably dental caries and periodontal disease, are
predominating among the ills that can compromise oral health.
Dental caries is the most common chronic disease of childhood!
Today we know that dental caries is a transmissible infectious
disease and that the bacterial pathogens are transmitted from
caregiver to infant during early childhood. Have you
read the recent paper by Soderling and colleagues,
"Influence of maternal xylitol consumption on
mother-child transmission of Mutans Streptococci: 6-year
follow-up" (Caries Research 35:173-177, 2001)? These
clinical science investigators have demonstrated that after
three years
and six years the maternal use of xylitol profoundly reduced
the dental caries experience of their children. Should we be
advocates in Southern California?
These microbes form a complex
dental plaque or biofilms that adheres to tooth surfaces.
Within these biofilms, Mutans Streptococci and several other
bacteria ferment sugars and other carbohydrates to form
acids. Repeated cycles of acid generation can result in
the microscopic dissolution of minerals in tooth enamel
resulting in dental caries. The initiation and progression of
this chronic infectious disease is modulated by genetic
variations of the microbial quorum sensing; colonization and
acid production within the biofilms; the host genetic
variations in enamel matrix composition and structure; and
both environmental and behavioral factors. Mechanical tooth
brushing, chemicals as well as immunological methods are used
to inhibit or reduce microbial colonization on tooth surfaces.
The advances from human and microbial genomics provide many
opportunities for targeted therapies such as vaccine
development for children at risk for dental caries. USC
faculty are currently engaged in these scientific adventures.
Just chat with Mahvash Navazesh, Casey Chen, Paul Denny, Steve
Goodman or Homa Zadeh for more information.
Chronic oral infections are
associated with heart and lung diseases, cerebrovascular
stroke, low-birth-weight, premature babies, and tissue/organ
transplant failures. In 2001, approximately 40 percent of the
American population presented chronic diseases and disorders.
One of the major chronic infections is periodontitis. There
are several microbes associated with this chronic and
destructive disease. Additional evidence implicates several
viral pathogens. The virulence of these pathogens includes
their role in colonization in subgingival biofilms, synthesis
and secretion of cytokines that can directly injure adjacent
tissues, and their capacity to invoke inflammatory responses.
Mutations in the cathepsin C gene are linked to the
Papillon-Lefevre syndrome that presents an extreme example of
destructive periodontal disease in children as well as in
adults. Completion of the human and microbial genomes and
functional genomic studies are beginning to reveal the
hereditability of susceptibility to a variety of infectious
diseases; critical cellular pathways associated with the
initiation and progression of disease; and candidate targets
for combined drug therapies. USC faculty such as Jorgen Slots,
Hessam Nowzari, Michael Jorgensen, Casey Chen, Steve Goodman,
and Homa Zadeh are engaged in scientific discoveries that will
significantly effect what is thought, what is taught, and what
is practiced.
Oral and pharyngeal cancers are
life threatening. With a five-year survival rate of just over
50 percent, one American dies every hour of oral cancer. Oral
cancer is the sixth most common cancer in U.S. males and takes
a disproportionate toll on African American males. Oncogenes,
proto-oncogenes and tumor suppressor genes are implicated in
oral cancers. Human and viral genome completions and a variety
of functional genomic studies suggest several gene-gene and
gene-environment (sunlight, alcohol and tobacco) interactions
that activate clusters of genes associated with cell growth
and/or cell death. Qualitative as well as quanti-tative
changes are being discovered through DNA microarray
techniques. USC faculty member David Crowe and his team are
engaged in these discoveries.
Birth defects and developmental
anomalies, frequently affect the craniofacial-oral-dental
complex. These appear most commonly as isolated cases of cleft
lip or palate, but clefting or other craniofacial defects can
also be part of complex hereditary diseases or syndromes. At
this time, hundreds of genetic mutations have been identified
that result in facial developmental defects and dental defects
in enamel, dentin, bone and cartilage. USC faculty Chuck
Shuler, Mal Snead, Maggie Zeichner-David, Janet Oldak, Yang
Chai and their teams are engaged in these discoveries.
Many systemic chronic diseases
and disorders such as diabetes, arthritis, osteoporosis,
chronic fatigue syndrome, fibromyalgia, Sjogren's syndrome and
AIDS, as well as therapies for systemic diseases, can directly
or indirectly compromise oral tissues. Using SNP-genotyping or
other high throughput technologies, the multiple genes in
complex human diseases will be identified, and the time of
expression and mechanisms of action will be ascertained. These
advances should lead to interventions for health promotion,
risk assessment and disease prevention as well as therapeutics
for treatment. USC faculty such as Hessam Nowzari, Winston
Chee, Terry Donovan and their team are exploring how to
improve implants and related prosthodontics therapy to address
treatment issues raised by chronic diseases and disorders.
These diseases and disorders of
the craniofacial-oral-dental complex at this time in human
history are coupled with the "golden age of molecular
oral health." The progress from the human genome,
microbial genomes, proteomics, bioinformatics and
biotechnology herald the promises of gene-based diagnostics,
gene-targeted therapeutics, and biomimetics with the
innovative design and fabrication of organs, tissues and
biomaterials. USC faculty such as Mal Snead, Janet Oldak,
Michael Paine and their team are pursuing innovations in
biomaterials for oral health care.
Risk assessment for disease is
increasingly being based upon subtle human and microbial
genetic variances. Gene mediated therapeutics are being
developed to enhance soft and hard tissue healing, repair and
regeneration. These multiple genetic variables are enhancing
our collective knowledge of susceptibility and/or resistance
to disease. A number of candidate genes have been identified
as risk factors for dental caries and periodontal diseases.
Gene therapy is being applied to treat oral and pharyngeal
cancers, xerostomia or "dry mouth," and to deliver
targeted therapy for oral infections and systemic diseases.
Nan Mulligan and Mahvash Navazesh and their colleagues in the
national study of AIDS in women and their children are engaged
in this clinical research.
Progress from the human and
microbial genomes, proteomics, physiomics, bioinformatics and
biotechnology is being made in understanding and treating
these and other diseases and disorders of the craniofacial-oral-dental
complex. The scientific and technological foundations of
dentistry, medicine, nursing, and pharmacy, as well as the
allied health professions, are expanding rapidly in parallel
with changes in the demographics of industrial nations,
changes in public expectations for enhanced quality of life,
and changes in the management and financing of health care.
Health professional schools are responding to these challenges
and opportunities. Public and private sector funding for
clinical research will continue to enhance multicenter,
prospective and randomized clinical trials, along with
behavioral interventions to advance health promotion, risk
assessment, and disease prevention. USC students, faculty,
staff and alumni practitioners alike must be prepared to adopt
evidence-based health care.
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