Occlusion (dentistry)

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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.

Malocclusion is the misalignment of teeth and jaws, or more simply, a "bad bite". Malocclusion can cause a number of health and dental problems.

Static occlusion refers to contact between teeth when the jaw is closed and stationary, while dynamic occlusion refers to occlusal contacts made when the jaw is moving. Dynamic occlusion is also termed as articulation. During chewing, there is no tooth contact between the teeth on the chewing side of the mouth.

Centric occlusion is the occlusion of opposing teeth when the mandible is in centric relation. Centric occlusion is the first tooth contact and may or may not coincide with maximum intercuspation. It is also referred to as a person's habitual bite, bite of convenience, or intercuspation position (ICP). Centric relation, not to be confused with centric occlusion, is a relationship between the maxilla and mandible.

Assessing Occlusion[1]

Extra-oral Assessment

  • Check for facial asymmetry and skeletal discrepancies
  • Measure Lower Face Height

Loss of teeth and occlusal stops can result in over-closure causing a reduced face height. Over-closure is unlikely for patients with tooth wear due to dento-alveolar compensation. Over-eruption may occur for patients due to dento-alveolar development in absence of tooth wear which may result in increased face height.

  • Temporomandibular Joints

The maximum extent the patient can open is measured between the incisal edges of the upper and lower incisors. Deviation of mandible on opening or closing should be described. Clicking, crepitus and tenderness of the jaw should be noted as well.

Intra-Oral Assessment

  • Intercuspal Position (ICP) / Centric Position

ICP is defined as position of the jaws when there is maximum intercuspation of the maxillary and mandibular teeth. Stability of occlusion in ICP is essential or further dental work will be complicated.

  • Retruded Contact Position (RCP) / Terminal Hinge Axis Position

RCP refers to the most comfortable posterior location of the mandible when it is bilaterally manipulated backwards and upwards into a retrusive position. Terminal hinge axis refers to an imaginary axis drawn through the center of the head of both condyles when the mandible opens and closes on an arc of curvature. When the mandible closes in the Terminal Hinge Axis, the first tooth contact refers to RCP.

  • Excursive Movements of the Mandible


Condyles move from the glenoid fossa in a forward and downward movement onto the articular eminence when the mandible moves into protrusion. Condylar inclination refers to the angle protrusion makes when the horizontal when the patient is sitting upright

In protrusion, contact between the teeth is governed by incisor relationship and guidance. For instance, the mandibular movement of patients with Class I incisors relationships would be inferiorly resulting in separation of the posterior teeth. This is to overcome the natural overbite of the Class I relationship for the mandible to make a protrusive movement.

Lateral Excursion

The side to which the mandible moves is called the working side and the opposite side is the non-working side. Bennett Movement refers to the lateral movement of the working side condyle when the mandible moves laterally. Bennett’s Angle is measured at the non-working condyle when it moves forward and medially during lateral excursion

Lateral excursion of the mandible is usually governed by Canine guidance or Group Function at the working side. In some cases, teeth at the non-working side can also be in contact when the condylar inclination is shallow or if the tooth guidance on the working side is shallow.

Occlusal problems

  • Malocclusion* is the result of the body trying to optimize its function in a dysfunctional environment. For example, the maxilla (upper jaw) can be placed too far anteriorly compared to the mandible (lower jaw). This would be called a Class II Malocclusion. If the mandible is placed too far posterior compared to the maxilla, it would be a Class III malocclusion. Malocclusion can can also be associated with a number of problems:
  • Misaligned ('crooked') teeth
  • Gum problems
  • The temporomandibular joint (TMJ and jaw muscles.

Malocclusion can cause teeth, fillings, and crowns to wear, break, or loosen, and teeth may be tender or ache. Receding gums can be exacerbated by a faulty bite. If the jaw is mispositioned, jaw muscles may have to work harder, which can lead to fatigue and or muscle spasms. This in turn can lead to headaches or migraines, eye or sinus pain, and pain in the neck, shoulder, or even back. Malocclusion can be a contributing factor to sleep disordered breathing which may include snoring, upper airway resistance syndrome, and / or sleep apnea (apnea means without breath). Untreated damaging malocclusion can lead to occlusal trauma.

Treatment for occlusal problems Some of the treatments for different occlusal problems include protecting the teeth with dental splints (orthotics), tooth adjustments, replacement of teeth, medication (usually temporary), a diet of softer foods, TENS to relax tensed muscles, and relaxation therapy for stress-related clenching. Removable dental appliances may be used to alter the development of the jaws. Fixed appliances such as braces may be used to move the teeth in the jaws. Jaw surgery is also used to correct malocclusion.[2]

See also


  1. ^ Advanced Operative Dentistry: A Practical Approach. David Ricketts, David Bartlett. 2011. pp. 69–86. 
  2. ^ "The History of Sleep Dentistry".  Sunday, 15 January 2017
  • "Tooth surface loss; Part 3: Occlusion and splint therapy" British Dental Journal, Vol. 186, No. 5, 1999-03-13, via nature.com. Retrieved on 2007-08-18.
  • Davies, S., and R. M. J. Gray, "Practice: What is occlusion?" British Dental Journal, Vol. 191, No. 5, pp. 235–245, 2001-09-08, via nature.com. Retrieved on 2007-08-18.
  • "What is Malocclusion?" (Website). American Academy of Pediatric Dentistry, 2007. Retrieved on 2007-08-18.
  • "Frequently Asked Questions: Jaw problems and headaches". (Website). British Dental Health Foundation, 2014. Retrieved on 2014-07-17.
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