Oregon Dental Assistants Association

Occlusion & Facial Profiles

where is your clue?

Oregon Dental Assistants Association Disclaimer

All diagrams are courtesy of the following websites:

dhonline.chattanoogastate.edu quizlet.com/8719964/skeletal-and-occlusal-

classifications-oral anatomy-flash-cards www.pua/edu.eg/PUASite/uploads/file/ Dentistry/Fall 2012

Oregon Dental Assistants Association

Prepared by:

Sheri Billetter CDA, EFDA, MADAA BS

There are 39 slides to view. For credits refer to the exam and answer sheet for instructions

Centric Occlusion

The relationship of the occlusal surfaces of one arch to those of the opposing arch.

posterior teeth are closed in a relaxed normal position.

anterior teeth have light contact. each person has their own individual centric

occlusion.

Angles Classification of Occlusion

Dr. Edward Angle developed classifications for occlusion in 1890.

he based his finding on the maxillary molar. it is important to remember that the

mesiobuccal cusp of the maxillary 1st molar is the key to occlusion.

exactly how does it interdigitate (“fit”) with the mandibular 1st molar?

Angle’s Classification of Occlusion

Class I – Normal

also known as neutro-occlusion

the MB cusp of maxillary 1st molar rests in the MB groove of mandibular 1st molar.

Class I

Look where mesiobuccal cusp of the maxillary 1st molar is located in comparison to the mandibular molar. Also look where the cuspids line up.

Angle’s Classification of Occlusion

Class II - Division 1

Distal Occlusion - Bucky Beaver appearance.

maxillary incisors tip outward from crowding.

MB cusp of the maxillary 1st molar is forward on the MB cusp of the mandibular 1st molar.

Class II

Notice the location of the MB cusp of the maxillary 1st molar.

Angle’s Classification of Occlusion

Class II - Division 2Distal Occlusion - Bucky Beaver crowded.

maxillary laterals protrude (tip facially) centrals retrude (tip lingually)

MB cusp of the maxillary 1st molar is forward of the MB cusp of the mandibular 1st molar.

Class II Division 2

Notice how far forward the MB cusp of the maxillary 1st molar is. Also the cuspid relationship and crowding in the anterior.

Angle’s Classification of Occlusion

Class III Also known as Mesial Occlusion Jay Leno, Carol Burnett - protruded jaw. lower jaw appears longer - may have a bulldog

appearance. maxillary incisors are “inside” mandibular

incisors when jaws are closed. MB cusp of the maxillary 1st molar is posterior

of the MB cusp of the mandibular 1st molar.

Class III

Location of the MB cusp of the maxillary 1st molar is distal on mandible. Cuspids and centrals are out of proper alignment.

A Bulldog appearance is common.

Types of Occlusion

Ideal Occlusion

RARE - Seldom Occurs there is a complete harmonious balance in the

relationship of the teeth and other structures. all 32 teeth are present . all 138 occlusal contacts are in a specific pattern. uses the 1st molar relationship. maxillary anteriors (slightly) overlap the

mandibular anteriors by 1/3.

Types of Occlusion

Normal Occlusion

variations are minimal. functional stability of alignment and occlusion

are maintained. 1st molar relationship is the key. molar relationship the same as ideal

occlusion.

Types of Malocclusion

What is malocclusion?

any deviation from the ideal. can be minor, moderate or severe. may involve several teeth . can include jaw position. 1st molar relationship is not always

involved.

Types of Malocclusion

Openbite

there is an existing space between the mandibular and maxillary teeth.

may be anterior openbite. may be posterior openbite. may be unilateral (one side). or bilateral (both sides).

Open Bite

anterior

Types of Malocclusion

Overbite

very deep vertical overlap - incisal edges of maxillary incisors extend far over the mandibular central incisors - can extend to the gingiva in severe cases.

maxillary incisors are over the mandibular incisors far more than the 1/3 overlap.

Normal - Moderate - Severe Overbites

Types of Malocclusion

Overjet

there is a horizontal overlap creating a protrusion or space.

between the labial surface of the mandibular incisors and the lingual surface of the maxillary incisors.

Types of Malocclusion

Severe Overjet

and posterior crossbite

Types of Malocclusion

Crossbite

teeth are positioned to the facial, buccal or lingual in contrast to its antagonist (opposing tooth).

can be maxillary or mandibular teeth. Can be anterior or posterior.

Malocclusion - Anterior Crossbite

Anterior crossbite before and after correction.

Malocclusion - Posterior Crossbite

Unilateral Posterior Crossbite - only on one side.

Malocclusion - Posterior Crossbite

Types of Malocclusion

Edge to Edge

occurs in the anterior teeth. the incisal edges contact each other edge to

edge. a cross bite or pre-crossbite condition can

exist.

Types of Malocclusion

Underbite

End to End

occurs in the molar areas there is no interdigitation of cusps or fossas - interdigitation is a natural fitting together. a cross bite or pre-crossbite condition can

exist.

Types of Malocclusion

Malocclusion

a malocclusion or deviation can be genetic or created by habits or muscular dysfunction such as:

thumbsucking or reverse swallowing

malocclusion classification depends on: the intensity, duration, how often it happens and the age it began.

Facial Profiles

Facial profiles are based on an imaginary line from the forehead, through the ala of the nose and to the chin.

Mesiognathic - considered a normal profile.

Prognathic - the mandible protrudes outward.

Retrognathic - the mandible retrudes, is small or under developed.

Facial Profiles

Deviations in Tooth Position

Torsoversion a tooth may be rotated ie: buccal wall may

face the lingual.

Infraversion tooth is not completely erupted.

Supraversion super erupted (over erupted).

Transversion tooth is in the wrong place in the arch.

Form and Function

Curve of Spee

a curvature formed by the maxillary and mandibular arches in occlusion.

curvature of the occlusal plane from the posterior to the anterior.

Curve of Spee

Form and Function

Curve of Spee

Mandibular Arch forms a slight curve inward concave (like the inside of a bowl) Maxillary Arch forms a slight curve outward convex (like the outside of a bowl)

Form and Function

Curve of Wilson

cross arch curvature of the posterior occlusal plane

extends from the tip of the right molar across the arch to the tip of the left

molar from the left to the right across the arch

Curve of Wilson

Form and Function

Functions of the Curve of Spee and the Curve of Wilson

accounts for strength and efficiency in chewing and the stability of teeth.

aids in defining occlusion. aids in denture construction. balances the arches for orthodontics.