|Sleep Apnea from an Anatomical and Developmental Perspective|
Occlusion – The Key to Dentistry
Researcher and presenter: Brian Palmer, D.D.S. December 2004.
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I designed this final presentation for my website as a continuing education or post-graduate course for dentists, but I have also tried to keep the terminology at a level that all health care providers and the general public can hopefully understand.
This presentation, as well as the other presentations on this website, are not designed to diagnose or make any recommendations for treatment for anyone. My website is designed solely for educational purposes only, but I am hoping it will help make for a wiser consumer. Everyone needs to consult with their own personal health care provider before making any health changing decisions.
WARNING:There are some illustrations, especially of cadaver dissections, that may not be suitable for viewing by all individuals. I feel the illustrations are necessary for a better understand of the issues being covered.
Occlusion is the key to understanding dentistry and this website. My ‘bible’ for occlusion is Dr. Peter Dawson’s book, Evaluation, Diagnosis, and Treatment of Occlusal Problems, 2nd Ed, C.V. Mosby, 1989. It is probably the only dental text book that I have read from cover to cover and which I recommend for all dentists to read, especially if they want a more in-depth understanding of this presentation. My understanding of occlusion is also based on the information obtained while attending the Pankey Institute where they use a Pankey/Dawson philosophy of occlusion.
To have a balanced ‘bite’, it is necessary to first have a good stable relationship of the ‘jaw joints’ or condyles of the mandible. Try to visualize the mandible as a stable inverted tripod (example - a 3 legged support for a camera, or a 3 legged stool or table). The three legs of the tripod are the two condyles (or jaw joints) and a front tooth (or front teeth). These 3 points govern the opening and closing of the jaw. The condyles are the hinges or sockets and the anterior teeth (anterior guidance) act as guides for the direction of movement during eating and chewing. None of the posterior (back) teeth should interfere during the opening or closing of the mouth. The jaw is like a nutcracker - the stronger cracking forces are closer to the back of the mouth just like they are closer to the hinge of a nutcracker. It is a lot more difficult cracking a nut at the front end of the nutcracker than at the back of the nutcracker. This principle is also true in the mouth.
The upper (maxillary) and lower (mandibular) anterior or ‘front’ teeth include 2 centrals, 2 laterals and 2 cuspids. When the jaw slides FORWARD, the ONLY teeth that should be contacting are the anterior teeth (Anterior guidance). If ANY posterior (back) teeth contact prior to any front teeth, then some damage could be caused around that ‘interfering’ tooth. Consequences are discussed in my articles on abfractions and lateral forces.
The cuspid or ‘eye’ teeth are designed for aiding in LATERAL (side) movements. Again, NO POSTERIOR (back) tooth should contact first when moving to the side. If any posterior teeth contact first, then the same consequences can occur as stated above. Once the slide extends as far as the cuspid can guide that slide, then the force is transferred (crossed over) to the other front teeth (centrals and / or laterals).
A simplified summary of occlusion as described in Dr. Peter Dawson’s book, Evaluation, Diagnosis, and Treatment of Occlusal Problems, 2nd Ed, C.V. Mosby, 1989, page 282, is as follows:
In the absence of noxious habits, "maximum comfort with stability can be predictably achieved if the following conditions are met for the anterior teeth.
1. Stable holding contacts for each anterior tooth.
2. Centric relation contacts occurring simultaneously with equal-intensity posterior tooth contacts.
3. Position and contour of anterior teeth in harmony with the envelope of function.
4. Immediate disclusion (separation) of all posterior teeth the moment the mandible leaves centric relation.
5. Position and contour of all anterior teeth in harmony with the neutral zone and the lip closure path.
Making every anterior relationship conform to a stereotyped ideal is not always possible because tongue-thrust swallowing patterns or lip-biting habits may alter the relationship"
Noxious habits can have a negative influence on orofacial musculature development and can definitely have an impact on the above basics of occlusion. These habits are covered elsewhere on this website.
There are several different philosophies on occlusion. I believe the best and most common occlusion / disclusion philosophy is best summarized in the phrase ‘cuspid rise with anterior guidance’. Some conditions do not always allow this to happen, so another form of occlusion / disclusion happens called ‘group function’ . During group function all the pressure during movements is progressively borne by all the teeth. This is most evident in prehistoric skulls where many of the skulls have very flat teeth.
I believe the best chance for an individual to have a beautiful NATURAL smile (no need for orthodontics) with a nice occlusion is if that individual was breastfed as an infant. Muscle always wins out over bone when it comes to positioning of teeth. The main reason breastfeeding (from a dental perspective) is so important, is that infants develop the proper peri-oral musculature and tongue action during the act of breastfeeding. This development is critical for the proper positioning and alignment of the teeth, the shape and width of the dental arches and the height of the palate. These points are covered in some of my articles available elsewhere on this website.
To open any section of this presentation, just click on the title for that section.
Section A - Basics of occlusion(112 slides, 2.6MB)
Definitions of terms
Section B - Consequences(95 slides, 3.9MB)
Section C - Influencers, Part 1(62 slides, 2.7MB)
Shape of the dental arch
Section D - Influencers, Part 2(60 slides, 2.4MB)
Section E - Facial form(77 slides, 3.6MB)
Long face syndrome
Section F - Conclusion(16 slides, 216K)
A6 - Probably the biggest disagreement in dentistry is where is the healthiest position of the condyle. This is a transcranial radiograph showing a condyle while the teeth are in contact, while just barely apart, and with the mouth open.
A34 - Important article. Key point - posterior contacts increase the activity of these powerful elevating temporal muscles - the more powerful the force, the greater the possibility of more damage from a lateral force or lateral blow to the teeth. Posterior contacts may also trigger bruxing and clenching habits by activating these powerful muscles.
A35 to A40 - A way to visualize the curvature of the occlusion of the lower teeth, is to visualize a ball with a 4" radius sitting on top of the lower teeth. The ball has both the front-to-back, and side-to-side occlusal curvature of the teeth.
A41 to A51 - Not very many people really appreciate or understand the importance of the tongue. I really believe there should be a ‘specialty’ in the study of the tongue. It is critical for chewing, swallowing, speaking, shaping the dental arches and palate, positioning of the teeth, and is a key player in ones ability to breathe.
A42 - Note the importance of the curve of Wilson here. The inside (lingual) cusp is lower than the outside (buccal) cusp. This is important because the slant of the cusps influences chewed food to be directed back into the mouth, instead of being directed toward the cheeks. This makes for more efficient chewing. Also note the little man (salivary glands) spraying digestive juices onto the food as it is being ‘recycled’ back into the mouth during chewing. These enzymes are important for the proper digestion of our food. Foods not chewed well or not exposed to the digestive enzymes can lead to digestive problems as described in these illustrations.
A43 to 45 - The restriction placed on this tongue by this tight frenum prevents this 13-year-old from mashing his food against his hard palate during the chewing process. The tightness of the frenum also impacts his ability to say certain letters or words.
A46 to A51 - I believe this is a beautiful example of how a tight frenum in this 26-year-old can influence and limit her inability to ‘dump’ or direct food laterally onto her teeth. She cannot chew her food as thoroughly as she should. This results in the digestive problems that she has. In this case however, her tight frenum did not appear to have an impact on the positioning of her teeth. She is also a singer. I feel this is a beautiful example, however, for those individuals who believe that tight frenums go away by themselves or have no consequences. I encourage you to look at the 2 presentations I have on frenums located elsewhere on this website.
A58 to 59 - The concept of a ‘neutral zone’ is important to understand. Muscles always win out in a battle with bone for position. Forces from the tongue and cheeks determine the position of teeth and have a major influence on facial development and form.
A60 and 61 - Another important concept to understand. When you want to crack a nut, you put it closest to the hinge to apply the greatest ‘cracking’ force. Not only will that force crack the nut better, but it could also crack a tooth better (if that nut - or popcorn kernel was in the mouth). You convert a nutcracker into a jaw by merely bending the nutcracker at the large arrows in B. C demonstrates where the strongest forces in the mouth will be. D is a very important concept to understand - as long as there is a good solid, stable stop at the front of the nutcracker, or in the mouth, even a delicate egg (represented in yellow) will not be crushed in the back - because the jaws of the nutcracker or the teeth in the mouth do not have the crushing force to do so (because they are prevented from coming closer together because of the stable stop up front).
A62 to 64 - People with square jaws like this have powerful masseters and usually have strong bites, flattened teeth, are bruxers and have enlarged mandibular angles (that can be seen on radiographs). Their nut cracking ability is a lot stronger than someone who has a large mandibular plane angle (more open-faced).
A65 to 71 - The key to occlusion is ones ability to MOVE the jaw as illustrated in these slides. The back teeth (bicuspids and molars) should not hit while moving in ANY direction. The front teeth should do all the guiding in all directions. Crossover is when the lower teeth cross over or past the guidance of the cuspid and then are guided by the other anterior teeth (laterals and centrals). While the jaw is moving, none of the posterior teeth hit. DURING CLOSURE, however, ALL teeth should contact with equal force at the same time.
A109 to 110 - Key slides. My research, and that of others, demonstrates that prehistoric skulls rarely had the malocclusions seen in our contemporary societies today. I hypothesize that the main reason for the lack of malocclusion in prehistoric times is due to the fact that prehistoric people had no other choice of nurturing their young except to breastfeed them. No bottles or pacifiers were available. Humans are the only mammals that use bottles and pacifiers. None of the other mammals have malocclusions. I wonder why humans can’t learn from the natural instinct of other mammals?
The high rate of occlusal disharmony in 1996 and the high rate of pacifier use in 1997 are not coincidental - they are directly related!
A111 - We MUST ADDRESS and TRY TO PREVENT the cause of these occlusal disharmonies EARLY in life and then TREAT the problem, if the parents are not willing to prevent the problem, as early as possible. These occlusal disharmonies greatly impact ones ability to eat, speak, breath and sleep. Waiting too long can have morbid consequences.
Most of this section is self-explanatory.
B24 and 25 – Models are mounted on an articulator. Teeth on the models are then stained. Models are then equilibrated on the articulator before doing any equilibration in the mouth. This helps avoid ‘surprises’. The amount of tooth and stain removed on the models now show which teeth will need to be equilibrated and by how much.
B35 to 38 – Articulated models were equilibrated until anterior guidance was achieved.
B73 to 75 - After she cracked her first tooth, I recommended a hard splint for this fairly petite lady, but she would not accept the fact that she bruxed or ground her teeth while sleeping. Not until she had cracked 4 teeth and had root canals and crowns placed on all 4 teeth, did she accept my recommendation that she needed a splint. She has made these deep grooves in what once was a fairly flat splint. She now believes that she is capable of bruxing at night and wears this splint every night. She has not cracked a single tooth since wearing the splint. This case demonstrates the powerful forces generated during bruxing - and what traumatic lateral forces can do to the dentition. Merely equilibrating the teeth would not have solved the problem of bruxing.
C6 and 7 - Note mid-palatal suture line. This suture line can be separated and expanded as long as the expansion takes place BEFORE this line ossifies (solidifies). Best to expand before age 16. I am not sure what the limiting age for expansion is. With the separation of this line, the pterygoid plates can also be expanded or widened and the palate can be lowered.
C8 to 10 - Covered previously in Section A, but repeated again because of the importance of the information.
C11 - There are several factors that can impact oral cavity and airway development, so it is important to understand that even breastfed babies can have malocclusions as well, although they are at less risk for having malocclusion. It cannot be stated that breastfed babies will always have perfect occlusions.
C12 - Any kind of illness that will cause an inflammatory response, edema and swelling will increase airway resistance and cause difficulty in breathing. One of the key problems today is transmission of illnesses at day care centers. Many times these shared illnesses result in enlarged tonsils and adenoids - which in turn leads to mouth breathing - which is a major contributing factor to oral cavity development, airway development and facial form. Not receiving the mother’s colostrum and breastmilk reduces an infant’s immune capabilities and also puts the infant at high risk for illnesses.
C13 - Allergies have the same impact as issues discussed in C12. Enlarged tonsils are a major contributor to upper airway resistance and sleep disordered breathing - which in turn are major contributors to physical and psychological development of an individual.
C14 to 24 - This is the key issue that links the importance of breastfeeding to dentistry - the development of a correct swallow. Note in both the Woolridge and Escott articles that during breastfeeding, there is a peristaltic or wave-like motion by the tongue that moves the milk from the breast to the throat. The tip of the tongue stays in an advanced position. The tip of the tongue initiates the suck, but the tip of the tongue does NOT move along the underside of the breast and ‘strip’ the milk from the breast. The mother’s ‘let-down’ process also aids the advancement of the milk. This process is covered in more detail in other presentations on the importance of breastfeeding on this website. The peri-oral and jaw muscles are also involved in the act of breastfeeding, thus developing a healthy coordinated effort by all the muscles around the mouth and jaws. The same proper development of the musculature does not take place during bottle-feeding.
The correct swallow developed and learned during breastfeeding, later becomes the correct adult swallow. Incorrect swallows cause abnormal forces and create the many malocclusions and consequences of those malocclusions in adulthood.
C56 to 59 - The shape of the mouth as explained by this formula in the article by Kushida is a major link to sleep apnea and sleep disordered breathing. I encourage you to read the 2 articles and editorial that I authored that were published in Sleep Review. You can link to those articles in the section labeled ‘Articles’ found elsewhere on this website. I then encourage you to review my presentation on sleep apnea that is also located elsewhere on this website.
C60 - A caliper like this may become a standard instrument in most medical and dental offices in the near future.
D1 to 4 - Large tongue size can impact the airway by blocking it. A large tongue can also impact the position of teeth by the force it exerts on them.
D5 to 18 - Frenums rarely go away by themselves and nearly always have consequences. There is not medical or dental advantage of having a tight frenum. Lingual frenums impact ones ability to swallow and speak. They can also make breastfeeding difficult because a tight frenum does not allow the tongue to compress the breast properly. Many times a tight frenum will cause sore breasts during breastfeeding and many times leads to a cessation of breastfeeding. The best time to address a tight frenum is at birth. Labial frenums are responsible for most of the diastemas or gaps people have between their front teeth. Labial frenums can also have a negative impact of breastfeeding because they may not allow for the flaring of the upper lip that is needed to create a good seal around the breast. I encourage you to review the 2 presentations I have on frenums on this website.
D19 to 25 - Decay can allow for loss of space and drifting of teeth. This drifting then impacts the position of other teeth.
D27 to 29 - This is the oropharynx of a 90-year-old gentleman. He is very healthy for his age. He only takes one pill for a stomach problem. A contributing factor to his good health is this very roomy oropharynx - which is part of his airway. KEY POINT - he could breathe well - because he had to have a large posterior nasal aperture (PNA) in order to have an oropharynx as wide open as he has.
D30 - His mother noticed a tremendous improvement in his alertness, interest in school and energy level once the tonsils were removed.
D36 - Key illustration: To go from a small posterior nasal aperture (PNA) that causes airway restriction to a larger, healthier PNA, expansion of the palate must occur before the mid-palatal fissure ossifies / solidifies.
D37 to 54 - Scientific principles involved in airway collapse and risk for obstructive sleep apnea. Explained in more detail in my presentation on sleep apnea found elsewhere on this website.
D42 to 44 - My hypothesis is that if a soft palate and/or uvula is/are located between two restricted air-tunnels that have air rapidly passing through them (nose and mouth have some blockage), that the constant stretch on that soft tissue, could elongate them. This would be similar to a flag standing straight out in a strong wind - but because the soft tissue is stretchable - it could elongate with time.
D59 - Bottle-feeding, excessive infant habits and pacifier use can create the malocclusions that research has discovered will put individuals at risk for obstructive sleep apnea. I am hoping this website will help educate mothers-to-be about the importance of breastfeeding. Breastfeeding is the key to good total health.
Everyone, I hope, wants his or her child to be as beautiful as possible. I am hoping this section is motivating to those who want that beauty for their child.
The ratio of 1.6 to 1 is a ratio that helps make things look ‘naturally pleasant’. The ratio is used by architects to help make buildings look good and the ratio is also used by dentists who do esthetic procedures to help make teeth look as pleasing as possible.
E7 to 37 - I use my assistant and her son, with her permission, to demonstrate the benefits of breastfeeding as it relates to natural beauty, beautiful dentition and airway development. She was breastfeed and she breastfed her son. Both have nicely proportioned, pleasing faces.
E9 to 15 - Her teeth meet the principles of occlusion as discussed in Section A.
E18 to 37 - WARNING: Some of the illustrations in this section are of cadaver dissections and may not be suitable for viewing by all.
E18 - Assistant is in the dental chair with an intra-oral camera placed in a position up behind her soft palate and directed forward - looking into her nasopharynx.
E22 - Anatomy of the throat and nasopharynx.
E23 - Circle is where head of camera is located - looking forward at the eustachian tubes, turbinates and nasal septum (removed in this illustration).
E26 - View as seen through the intra-oral camera.
E30 to 32 - A great research project for someone would be to see if there is a relationship in these measurements. It could determine who is at risk for sleep apnea. Not everyone, however, can get the intra-oral camera into that position.
E33 - Camera turned down from previous position to illustrate her epiglottis and vocal cords.
E34 to 37 - Not to be outdone by my assistant, I also took pictures of my nasopharynx. I was breastfed also, and despite being a little gray and balding, my ratio actually turned out better than my assistant’s ratio. This was probably due to operator error as we were only using a basic ruler and not calipers.
E38 - I added this slide here because of the illustrations of the nasopharynx(s). Being able to see the eustachian tubes so clearly in these illustrations, you can see where if there was a lot of congestion, infection or blockage in the area of the tubes, how an infection could easily get up the tubes and cause otitis media.
E39 - 53 - This gentleman was the same age as my assistant - only difference is that he was a preemie and was bottle-fed. I strongly believe that the difference in his facial contour, occlusion, open bite, tongue thrust, narrow arches and congested oropharynx were all due to the fact that he was bottle-fed.
E54 to 55 - Another adult with a well proportioned face, a beautiful smile and nice arch form. She was exclusively breastfed and refused bottles and pacifiers. Smart baby!
E 56 to 59 - Comparison of 2 boys of the same age at 4 months and at 4 1/2 years. One was breastfed; the other was bottle-fed and was a very aggressive thumb sucker.
E57 to 71 - The same excessive thumb sucker documented over 11 years. His excessive thumb sucking habit has had consequences and has cost a lot of money.
E73 to 75 - Classical characteristics of an adult with long face syndrome.
E76 - Everyone’s throat should look like this. If it does, you are probably pretty healthy, have a well proportioned face, nice occlusion, breathe well, sleep well, and hopefully don’t snore.
E77 - Get your rulers out and start measuring to see who has well proportioned faces.
F1 - The mouth really is like a crystal ball IF you know what you are looking for. I hope this presentation will help other dentists and health care providers see things they were not taught in dental or medical school.
F3 to 4 - The swallow we develop during infancy continues on into adulthood. The correct swallow is developed during breastfeeding.
F5 to F7 - If we can screen for signs of obstructive sleep apnea (OSA) during every exam, I feel we are providing an excellent service for our patients. Prevention is so much better than waiting until someone has a heart attach or a stroke before determining they have OSA.
F8 and 9 - Evaluating for a high palate, narrow arches and cross-bites should be part of any health care screening process. High palates and narrow arches should be treated early - preferable before the ages of 16-18.
F10 - This IS the key issue of this website. There is a significant relationship between bottle-feeding, excessive noxious habits and pacifier use to the malocclusions that put individuals at risk for obstructive sleep apnea.
F11 - Obesity is also a major health problem, particularly in the USA. Another belief that I have is that obesity, obstructive sleep apnea, sleep disordered breathing and smoking may eventually bankrupt our present health care system. We ALL need to practice prevention and good health habits, or NOBODY will have quality health care in the future.
F12 - Breastfeeding is the best form of health care, and it is also the cheapest. I strongly encourage you to support breastfeeding in your society.
F15 – I would like to thank Kansas University for giving me a 4-year football scholarship. Without that scholarship I would not have been able to afford to go to college, would not have gone to dental school, would not have done any of this research and would not have been able to develop this website. Thanks KU! Go Jayhawks!
For Better Health!
Brian Palmer, D.D.S.
Leawood, Kansas, USA