What Angle is the Occlusal Plane Relative to the Horizon?
by Clayton A. Chan, DDS, MICCMO
Nature has amazingly design the masticatory system in such a manner to meet the functional demands in a very physiologic manner. Our occlusal, cervical, airway and postural complex has been pre-determined genetically to function optimally relative to earth’s gravitational forces. Because of gravity, the muscles of the structural system as well as the masticatory system allows the human being to function with the head in properly balanced manner to avoid strains and fatigue to the overall postural system. Hence, a person with a forward neck posture, which has resulted to accommodative and maintain the air flow of oxygen into the body will exhibit a flatter occlusal plane tendency indicative of an upward head tilt. The upward head tilt contributes to TMD and accommodative pathologic issues (e.g., shoulder pain, neck pain, temporal headaches) that tries to defy natures gravitational vertical forces, resulting in a flatter more leveled occlusal plane which does not represent what nature originally intended in its design.
The SN Plane is noted in the dental literature as a standard objective leveling reference. What you see in the lateral ceph below is one of one of my patients, male age 47 who presented with former TMD cervical neck problems. Symptoms were resolved with an orthotic. Head tilt corrects, including and improved occlusal plane for me to transfer to fabricate the upper and lower restorations for FM rehab. This is what I recorded. It seems to me that if SN plane is level, symptoms are gone, and patient’s head is now balanced, it seems to me that simply recording this position is the most logical to communicate with the lab to mount the case.
This is the actual photo that some skeptics have tried to alter to disparage the modified Fox Plane technique I have been advocating. (Important Note: In the background the level counter and bottles sitting on top shows that my patient’s head is leveled. The bottles and level counter top are not slanting and or angled as some scrupulous ”instructor/teachers” have tried to convey in their lectures by altering this image in their lectures to distort the truth of my Fox Plane recording). Level = Level!
I check the crown ratios (they shouldn’t look funny)…reconfirm my AP…check my patient’s subjective responses. Many dentist and I have discover that when the correct occlusal plane is properly managed, the patient doesn’t experience any neck, cervical and shoulder pain problems. If one uses the classic HIP (hamular notch and incisive papilla) method to manage the case too completion that many are discovering that this can lead to unresolved TMJ/occlusal problems. If everything seems to line up I go for it!
I mount my cases and check my cases from the lab to see if they maintained the correct maxillary orientation before delivery (labs are not allowed to cheat or change the mount unless it is wrong). I check my mount. I check the photos, I check and compare what is in the mouth, I check how the angle and slant is…I analyze and re-analyze and confirm with my lateral ceph, check my EMG data (making sure my patients are comfortable and stable), I check my Scan 4/5, scan 2’s, scan 8’s, etc. and decided that this orientation got to be right from the frontal and lateral views….then a re-check the patient and I re-check at the lab bench…. Seems right to me!
I am happy…that He is happy…. “Don’t lose sight of the Power of the Bite!” I have no regrets about the Fox…because I know it works for me and it works for all the talented clinicians who understand this concept. These pictures are immediately after lower seat, before any adjusting of any crowns….I had the patient come back the next day to TENS and refine the bite.
My patient is very pleased, no neck cervical TMD problems. The bite is awesome. After gneuromuscular esthetic dentistry the patient no longer reports cervical pain, no shoulder pain, nor any TMD issues. The patient is stable and very happy. He is a public speaker and is on streaming internet video weekly and has a great pleasing smile. You can view him at: http://www.iclv.com/ or spiritflow.net on Sunday mornings and Sunday evenings.
Although, there is some dental literature that tries to indicate that the occlusal plane is parallel to certain boney references as the hamular notch and incisive foramen) they often do not realize that cervical bones from C1 to C7 are not perpendicular, thus misleads and confuses the reader as to which horizontal they are refering to. Dental literature both in the orthodontic, restorative and prosthetic arena clearly have reported on average an occlusal plane angle of 6-14 degrees when the horizontal gaze is parallel to earth’s horizontal level. Any dental referencing technique that advocates an occlusal plane horizontal to earth’s horizontal plane certainly is contributing dental failure and postural/occlusal instability.
Dentists have ignored physiology far too long and have destroyed much with their hands, what nature has spent years growing and developing. A flat occlusal plane relative to horizontal level represents mal-alignment and dysfunction contributing to body fatigue. Neuromuscular science supports normalize occlusal form. If clinicians ignore what nature intends they WILL be building fatigue into their cases. You cannot fool physiologic and anatomical science, especially when it is tested amongst thousands of great clinicians who understand the realities of conservative, ethical and thoughful judicious “gneuromuscular/neuromuscular” treatment for their patients.
As you all know I take a lot of records and this is just a small sampling of what many have been privately emailing me to show what I do. Some may not agree, but I am fine with that. My patient is extremely happy and satisfied.
The occlusal plane should look natural and balanced with the smile (that is how it should appear)…the mount is what tweaks our minds…the lateral ceph objectively confirms the reality, but it may be a need for a paradigm shift in occlusal thinking and re-evaluate whether your occlusal plane mount is too flat or not. It’s worth investigating.
Conclusion:
1) We ultimately desire the cervical neck muscles balanced, thus we observed that the head tilts downward from an upward pathologic TMD position which TMD patients present with (flatter occlusal plane relative to horizontal level), 2) we desire optimal esthetics smiles lines and our patients to be asymptomatic. We observe on lateral cephalograms that the occlusal plane is angled – no symptoms and 3) we simply desire to reproduce what we actually see in a stable, symptom free system – angled occlusal plane, and not have our lab technicians guess or alter the mounts, thus the Fox plane method we advocate as many recognize as simple and logical is easily transfered via the Fox Plane method indicated at Occlusion Connections.
© 2009 Clayton A. Chan, DDS. All Rights Reserved.
