Dental Occlusion / Anterior Guidance Part 1

Should I be concerned about Dental Occlusion / Anterior Guidance?

If your dentist is blabbing about how bad your bite is and throwing in a few complex words like dental occlusion, anterior guidance and premature contacts, should you be concerned? At Westcoast dental clinics in Vietnam, we’ll try to answer these questions about dental occlusion for you in a simpler way.  If you know or have been informed that there is a problem with your bite, then it’s essential for you to understand how this problem can be improved. If you are considering a full mouth of dental work in the future to correct your bite, we trust this article will be useful and help you understand the complexities of such treatment.

Is it important for you to understand all of this? Well the short answer is no!
Most people who have undiagnosed bite issues don’t realize the seriousness of the condition. The truth is it can lead to the premature wearing down of your teeth, or the need for
root canals and even a very unaesthetic smile. If left unattended, you may even suffer from repeated tooth fractures and the loss of teeth.

Undiagnosed dental emergencies such as breaking a tooth may continue to happen despite all the brushing and flossing you do. You can try to understand the complexity of the oral mastication system, but frankly it’s quite technical. Even dentists with many years of practice continue to take courses on dental occlusion. Some study at world renowned institutes such as LVI, Dawson or Pankey, to keep up with the latest scientific advancements and expanding technologies.

Dental Occlusion: Cracked Teeth

Is it important to know about a little bit about dental occlusion as a patient? The short answer is yes if you want to get the best result. This is especially important if you want to prevent or stop suffering from having to experience a litany of dental emergencies that is caused by the overall state of your bite. If you are the type of person who prefers being well informed and clearly aware about the treatment processes, then getting more involved with the planning and design will help you get a great result. In this article  about dental occlusion our goal is to make sense of this for you.

If you are considering investing in a full mouth of crowns or veneers, or dental implant treatment such as all on 4, or all on 6 or pro-arch treatment, then these general rules and principals  will apply to you. We, at Westcoast in Vietnam, have come up with this two part article to inform and help you understand this somewhat complex topic.

Part 1 covers the definitions and quirky terminology that dentists use. In part 2, we will focus on putting these term in use by explaining what is trying to be achieved and what the dentist and lab will do.  Hopefully at the end, you have a better understanding what your dentist and dental technician will do when designing a new bite. 

There treatments of course do not come without a hefty price tag and considerable amount of work.  Having 16-28 crowns done is considered a very complex irreversible procedure that can needs to stand up to very stringent criteria in order to eliminate or reduce problems for you five to ten years from now.

Let’s begin with the first term “Dental Occlusion”, a important general term which dentists refer to has the way your teeth bite together. Wikipedia defines it “Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.”

Normal Dental Occlusion Westcoast

Every dentist is checking and working on your “dental occlusion” as a chance to maintain or to improve your bite when doing any dental restoration.

Normal Dental Occlusion Midline

Normal Dental Occlusion Midline Westcoast

Below are a set of dental definitions that are commonly used.

Dynamic occlusion
Dynamic occlusion is the concept of how the upper and lower teeth contact one another when the lower jaw (mandible) is in motion. As an example, try the following maneuver: Start by moving your lower jaw forward and then back to the closed teeth position. Next move your teeth so lower jaw is to the right, then back to the closed teeth position and finally to the left and back to the teeth closed position. All these points of contacts as you are moving towards are the lines of direction of your occlusion. You can move forwards, sideways, backwards slightly and at angles towards the canines. Think of these movements as generating lines. This is your dynamic occlusion.

What determines the shape of these lines?  Why is this important?

The shapes of these lines will determine what type of dynamic occlusion you have. It’s important because every one is different and you want to have an occlusion that is ideal for you.

Your jaw movements are made possible by the muscles of mastication, a group of muscles including the masseter and temporalis muscles. When you make a movement, it’s these muscles that contract to allow you to move along a line.

The actual lines depend on a combination of teeth positions and the shape of your teeth (steepness or flatness).

TMJ (jaw joint also known as Temporo-Mandibular Joint)
Your jaw has a special joint known as the temporo-mandibular joint, commonly known as the TMJ. If you place your fingers one centimeter forward from your ears, you can feel the TMJ when you open and close your mouth. This joint can be affected by teeth trauma, grinding or the loss of teeth, just like your neck suffering an injury. More importantly, it is the shape and position of the teeth that creates your current occlusion but the shape of your TMJ can also be a factor.. Dentists and dental laboratory technicians must determine the precise position and design of these shapes, in order to create a favorable dynamic occlusion. When the TMJ is not aligned to the teeth, or the teeth are not aligned to the TMJ, we can get Temporo-mandibular disorder, or known as TMD, a disease of the jaw joint that usually associated with pain.

Dental Occlusion - Temporomandibular - TMJ - Westcoast

Anterior Guidance
Anterior guidance is a favorite dental term used by dentists to explain how an ideal dynamic occlusion should be. It refers to the ability of your teeth to slide at the front without interrupting your back teeth.

Anterior Guidance Dental Occlusion Westcoast

In your bite, we refer to a working side and non-working side. The working side is where you are sliding your lower teeth to one side (use the canine position), your working side is the same side you are sliding. The non-working side is the side not being engaged. What is important to remember is this, with your non-working side there are no occlusal interferences. 

Dental Occlusion Working Side Interference Westcoast

What are occlusal interferences? It’s another crazy dentist term also referred to, as nonworking contacts or interferences. Dentists want to remove or prevent these from occurring.

Working side interference
When you move your jaw to one side, we want your teeth to slide over on the same side. These contacts are known as working contacts. There are two categories of working contacts known as canine guidance or group function.

Canine Guidance
If you slide you teeth to one side and your canine is the only one that guides your teeth, then you have a situation of canine guidance. This comes from an evolutionary trait in which the canines have the longest root and are best designed to take the loading forces when moving side to side.

If you have canine guidance, then you have anterior guidance as well and therefore a very good protective case of dynamic occlusion!  This is a key point.  You want to have canine or group function (below) in order to have a good bite.

Canine Guidance Westcoast

Group function
Making contact with more than one tooth when you move your jaw in a sideways motion. Is known as group function, it is second to canine guidance. 

Group Function Westcoast

Group Function Westcoast

A non-working side interference
Occurs if you slide to the working side and make contact with the other side, you don’t want this!

A key point is that we don’t want non-working interferences because they contribute to an unstable bite.

Dentists can and often should remove these because research shows interferences cause the brain and masticatory system to receive negative impulses when movement occurs. Furthermore, these interferences cause tooth trauma which should never be manufactured by the dentist if we want to achieve the best results for your dental health.

In all human beings, anterior guidance protects the posterior teeth. Simply stated by lifting up the back teeth, the back teeth are protected. When there is no anterior guidance the back teeth make contact with the front teeth and you run the risk of intense, accelerated, wear on your teeth. The sum of which will eventually be affected by TMJ disturbances.

An analogy to consider is that of a nutcracker. The closer the nut is to the hinge,  the more power you can generate. It’s a class 2 level and the jaw operates the same way. The closer the general function is to the jaw joint, the greater the force on your teeth. This is so because the posterior molars function like a class 2 lever, just like a nutcracker.

Nutcracker Dental Occlusion

The greatest force is taken by the back teeth, the molars. But you don’t want this to happen all the time because your teeth are going to be subjected to an excessive amount of pressure. By having anterior guidance we can take the constant pressure off the back teeth. Thus allowing for, a more balanced distribution of the force over all your teeth.

Anterior guidance is determined by the position and shape of the front teeth. 

Anterior Guidance

The shape of the upper front teeth in particular the length, contour of the back surface and their positioning. Essentially are the determining factors for creating anterior guidance. The height and edge position of the lower teeth and the general position of the lower front teeth, contribute to the equation to a lesser degree.

Imagine a person with front teeth that are too flat, has an open bite or is missing front teeth. Basically their front teeth will be unable to touch the lowers. 

People who lack have anterior guidance are more likely to have damaged, missing, or long term teeth problems. This occurs because they lack the protection that anterior guidance provides. They generally will suffer more wear and tear because of this condition.

Well there you go! We hope you enjoyed Part 1 on dental occlusion. If you found it difficult then you are not alone! Dentists everywhere take courses to demystify this topic. They include these important concepts with every filling, crown and full mouth crown case they perform. Here at Westcoast Vietnam, all dentists and dental technicians speak and live by the definitions of dental occlusion.

If you’d like to learn more about it all, specifically, “What dentists do to help restore anterior guidance?” Please, read Part 2, which will be dedicated to this crazy topic.

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