Dr. Mark A. Cruz is committed to taking a multi-disciplinary approach toward airway problems such as sleep disordered breathing. Dr. Cruz and his colleagues strive to improve the way dental health conditions related to the teeth, muscles, and the TMJ (temporomandibular joint) are addressed. Providing an approach to patients' dental health that is grounded in global wellness is the goal of the course he co-developed with orthodontist Dr. Barry Raphael. The course is called Airway Focused Dentistry Mini-Residency. Together, Dr. Cruz and Dr. Raphael are educating doctors on the West and East coasts about the relationship between the structure and function of the human airway and facial development. Dr. Cruz kicked off the 2-day course in July at the Renaissance Club Resort in Aliso Viejo, CA.
'The Great Leap Forward'
To highlight the importance of the airway and upper respiratory evolution, Dr. Cruz provided history about the evolution of humans. The evolutionary changes in the human's upper respiratory tract to facilitate speech led to a phenomenon UCLA physiologist Jared Diamond calls "The Great Leap Forward."
During the Paleolithic Period, also known as The Stone Age, Homo sapiens had sizable brains and made tools. It is well-documented that Homo sapiens lived in small bands of 6 to 10 people. This made sense in regards to hunting and sharing food.
About 40,000 years ago, the vocal tube anatomy and the necessary neuro connections that allowed Homo sapiens to have speech were completed, and they were able to create language. The other major evolutionary change was bipedal locomotion that freed up their hands to have precise work. Speech facilitated the Dawn of Civilization 10,000 to 12,000 years ago. The ability to control the food supply allowed them to move from small clans to full civilizations. Bipedal movement and the ability to communicate with speech separated man from the rest of the animal kingdom and permitted the human race to evolve to advanced civilization.
Unlike other mammals, Home sapiens are brachycephalic; meaning they have flat faces. The English bulldog has problems breathing which is called brachycephalic syndrome, a condition that leads to severe respiratory distress. When humans became bipedal, the airway became restricted. Airway dysfunction, including sleep disordered breathing, is an adverse consequence of the human upper respiratory evolution. The development of speech contributed to this dysfunction.
The human is the only mammal that has a descended larynx, which is located between the third and fourth vertebrae in a child and descends at about six months. We are born as obligate nasal breathers because we do not have the neuro connections necessary to breathe through the mouth. Therefore, sleep disordered breathing is an anatomic illness, Dr. Cruz said.
Craniofacial growth and development
The largest increase in craniofacial growth occurs in the first four years of our lives. From an infant to an adult, there is a difference in the angle of growth; which can constrict the airway.
Dr. Cruz shared the following statistics regarding craniofacial growth:
- It is 90 percent complete by age 12.
- Eighty-nine percent of youth, ages 12-17, have some occlusal disharmony.
- Sixteen percent of youth have severe handicapping malocclusion that requires mandatory treatment.
"Let's not focus on the teeth. Let's focus on the face and, more importantly, the airway. The airway is what actually drives facial growth," Dr. Cruz said.
Malocclusion (poor bite) is not an aesthetic issue that needs to be corrected by braces. It is due to improper growth, he said.
"The first and most important area of craniofacial growth and development are the individual's breathing habits. Our entire character and physiology is set up to protect this function first and foremost. And, it's driven by the most primitive part of the brain," Dr. Cruz said.
There is no question that there is a direct relationship between the growth and lack of growth of the upper and lower airway with nasal respiratory function, Dr. Cruz said, before concluding his presentation with a quote from well-known orthodontist Dr. Robert Rickett.
"From the environmental standpoint, total respiratory function has been the most overlooked factor in clinical orthodontics. The influence of the beliefs in the 30s and the 40s, the concepts of genetic dominance and the conviction of limited skeletal alterations as a possibility in therapy, led to the concept of treating just the teeth instead of the face or the patient as a whole. Biologically, the functions of mastication and respiration have been connected with the same set of muscles and the same set of nerve paths. We cannot separate them."