What Angle Is the Occlusal Plane Relative to the Horizon?

What Angle is the Occlusal Plane Relative to the Horizon?

Originally published May 2015 · Last updated May 2026

By Clayton A. Chan, D.D.S. — Founder/Director of Occlusion Connections™

Nature’s Design for the Masticatory System

Nature has amazingly designed the masticatory system in such a manner to meet the functional demands in a very physiologic manner. Our occlusal, cervical, airway, and postural system has been pre-determined genetically to function optimally relative to earth’s gravitational forces. An angled or slanted occlusal plane is nature’s design when the head is properly supported by balanced muscles.

Because of gravity, the muscles of the structural system as well as the masticatory system allow the human being to function with the head in a properly balanced manner — to avoid strains and fatigue to the overall postural system.

The Forward Neck Posture Pattern

A person with a forward neck posture will accommodate to maintain the flow of oxygen into his/her body. This forward neck and head posture tendency is indicative of an upward head tilt with a resulting flatter occlusal plane. The upward head tilt contributes to TMD and accommodative pathologic issues — including shoulder pain, neck pain, and temporal headaches.

This upward head tilt is the body’s way of accommodating a malaligned bite that tries to defy nature’s gravitational vertical forces — resulting in a flatter, more leveled occlusal plane that does not represent what nature originally intended in its design.

The SN Plane as Objective Leveling Reference

The SN (Sella-Nasion) Plane is noted in the dental literature as a standard objective leveling reference. What you see in the lateral ceph below is one of my patients — a male age 47 who presented with former TMD cervical neck problems. Symptoms were resolved with an orthotic. The previous upward head tilt responded positively to the orthotic therapy, allowing nature to correct its head posture — including an improved occlusal plane.

Based on this corrected and more normalized occlusal plane orientation as seen in the lateral cephalogram below, I want to transfer this occlusal plane orientation to a flat analyzing table on my articulator to fabricate the upper and lower restorations for full-mouth rehabilitation esthetically and anatomically.

It seems to me that if SN plane is level, symptoms are gone, and the patient’s head is now balanced — recording this position is the most logical way to communicate with the lab to mount the case.

Recording the Maxillary Occlusal Plane With the Fox Plane

To record this maxillary occlusal plane orientation, I use the Fox plane as indicated in the blog articles and other publications I have written. It takes the guess work away from the laboratory — as long as you implement the process properly, like anything. Errors can occur during the following steps:

During the bite registration stage. If one uses computerized mandibular scanning (jaw tracking — e.g., Scan 4/5 with J5 Dental TENS) and does not have adequate training to accurately interpret and record this kind of neuromuscular bite registration, error can occur before the case is even started.
If the EMG interpretation is not correct and one implements erroneous EMG diagnostic protocols — unable to decipher the differences between fatigued EMG patterns vs. normalized EMG patterns, or does not monitor the cervical group EMGs believing that these EMG recordings are the same as SCM EMG recordings — one will be greatly mistaken.
Subjective interpretation in these areas of diagnostics will also lead to failed treatment results.

I believe in using good artistic and scientific clinical judgments to record head levelness — like any diagnostic protocol. Using the Modified Fox Plane technique as I have formerly indicated is a simple, inexpensive, and effective tool every dentist in North America can use. (By the way, every dental student has been issued a Fox Plane in dental school as a basic learning tool.) Note the angle of the occlusal plane.

(These are real time pictures that I routinely take during my clinical workup to document what I actually observed.)

Note how the maxillary recording is simply recorded at level using fast-set polyvinyl on the bite fork of the Fox Plane and then transferred to a level table. This nicely correlates with the lateral ceph occlusal plane, which objectively confirms the mounting and occlusal plane transfer.

The maxillary cast is simply transferred to the table via the OPI (occlusal plane index) from the Fox Plane recording. Read more on Mounting the Maxillary Dental Cast Using the Fox Plane →

Defending the Fox Plane Recording Against Misrepresentation

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 show that my patient’s head is leveled. The bottles and level counter top are not slanting and not angled — as some scrupulous “instructor/teachers” have tried to convey in their lectures by altering this image. Level = Level!

In a purposeful attempt to disparage and misconstrue the facts of my published article, a dentist instructor “teacher” of a “cosmetic NM teaching center” used this picture, altered and flipped it, in an attempt to discredit my teachings during his lectures. What is amazingly wrong with his attempt is that he failed to fully read and comprehend the article that was published in the ICCMO Anthology — Chan, CA: A Review of the Clinical Significance of the Occlusal Plane: Its Variation and Effect on Head Posture: Optimizing the Neuromuscular Trajectory — a Key to Stabilizing the Occlusal-Cervical Posture. International College of Craniomandibular Orthopedics (ICCMO) Anthology VIII, 2007.

His biased publicized lecture subtitle shown in the below power point slide shows his unscrupulous dishonest disregard for scientific and academic teaching integrity — and is in itself a “contradiction”. Additionally, it shows his lack of knowledge and understanding of basics in lateral cephalograms.

This is the altered and flipped picture by this “occlusion teacher” with the accompanying text:

Below is the unscrupulously altered photo by the same dentist (instructor “teacher” of an institute) who purposely altered my photo again in a second power point slide (by rotating and altering the above photo) and used it without permission — in a manner to give a misleading and false impression to the attending listening doctor audience about my occlusal plane teachings and understanding of how I advocate the use of the Fox Plane.

One of my dentist colleagues discovered and reported this poorly mishandled power point slide, exposing this doctor/”teacher’s” credibility as an “occlusion instructor” by pointing out in the background the tipped bottles that were positioned on a counter in the background. The unethical teacher/lecturer purposely rotated the photo to mislead, misguide, and convey a false teaching about me and what I believe about head posture, the maxillary occlusal plane orientation, and what I consider as horizontal level.

The lecturer/”occlusion teacher” has exposed his credibility and lack of academic honor. Such stupidity does not go unnoticed by those who have astute eyes to see beyond what is obvious.

Postural balance is maintained best when the head, neck, shoulders, pelvis, and feet are leveled to Earth’s horizontal level. Dentists and the viewing audience clearly recognize what level is and realize that the angled human occlusal plane is simply determined when the dentist can clearly see things from a balanced perspective — not from a distorted, biased, and altered view.

The Lateral Cephalogram as Objective Confirmation

The unposed head posture clearly shows the natural angled occlusal plane of the same patient in this lateral cephalogram.

Lateral cephalogram (ICAT) after comprehensive restorative treatment. Note: unposed natural head position and natural angled occlusal plane. Images have not been altered or modified. (You decide… is the occlusal plane angled or flat?)

From Wax-Up to Final Restorations

The wax up was done to match the mount using the maxillary transfer table. Restorations were fabricated to the same mount without alterations to the mount. (Dr. Chan proudly gives recognition for outstanding ceramic and waxing to Las Vegas Esthetics Lab, Ray Foster and Team.)

I check the crown ratios (they shouldn’t look funny), reconfirm my AP, and check my patient’s subjective responses. Many dentists and I have discovered 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 to completion, many are discovering that this can lead to unresolved TMJ/occlusal problems. If everything seems to line up, I go for it!

Verifying the Mount Against the Patient

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. I 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 decide that this orientation has got to be right from the frontal and lateral views. Then I re-check the patient and re-check at the lab bench. Seems right to me!

The Final Result

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, shoulder pain, or any TMD issues. The patient is stable and very happy.

What the Dental Literature Says About Occlusal Plane Angle

Although there is some dental literature that tries to indicate that the occlusal plane is parallel to certain bony references (such as the hamular notch and incisive foramen), they often do not realize that cervical bones from C1 to C7 are not perpendicular — thus misleading and confusing the reader as to which horizontal they are referring to.

Dental literature — both in the orthodontic, restorative, and prosthetic arena — has clearly 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 is certainly contributing to dental failure and postural/occlusal instability.

Before and after gneuromuscular esthetic dentistry full-mouth restoration showing natural angled occlusal plane and corrected head posture — Dr. Clayton Chan, Occlusion Connections, Las Vegas

The Physiologic Occlusal Plane

A physiologic occlusal plane, determined by balanced cervical neck, shoulder, and masticatory muscles of the head, is routinely angled by nature’s design to be perpendicular to a normalized lordotic curvature of the neck from C1 to C7.

This orientation is physiologically sound according to nature’s proportional design for:

Optimal function of the pharyngeal airway (breathing)
Optimal head posture for physiologic functioning and positioning of the lower jaw
Proper shoulder posture

Proper mandibular positioning relative to the cranium does affect and impact body balance, flexion, extension, and rotational movements.

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 malalignment and dysfunction, contributing to body fatigue.

Neuromuscular science supports normalized 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 thoughtful 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 to re-evaluate whether your occlusal plane mount is too flat or not. It’s worth investigating.

Conclusion

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).
We desire optimal esthetics smile lines and our patients to be asymptomatic. We observe on lateral cephalograms that the occlusal plane is angled — no symptoms.
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, is simple and logical and easily transferred via the Fox Plane method indicated at Occlusion Connections.

To read the complete published article: A Review of the Clinical Significance of the Occlusal Plane (ICCMO Anthology VIII, 2007) →

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Written by Clayton A. Chan, D.D.S. — Founder and Director, Occlusion Connections | Las Vegas, Nevada

6170 W. Desert Inn Road, Las Vegas, Nevada 89146 | Telephone: (702) 271-2950

www.occlusionconnections.com

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What Angle is the Occlusal Plane Relative to the Horizon?