Intro to Occlusion Exam 1 [Dental Occlusion: Marshall]

Define primary tasks of dental occlusion in modern Homo Sapiens

Food intake: Biting/cutting

Mastication: Food crushing

Ensuring the minimal distance between mandible and maxilla necessary for optimum functioning of the masseter and medial pterygoid muscles

Ensuring the vertical dimension between upper and lower jaw

Speech articulation: Particularly anterior teeth

Jaw clenching and tooth grinding

Tool and weapon

Occlusion

The static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues

Occlusal contact

Any contact relationship of opposing (maxillary and mandibular) teeth

Articulation

The static and dynamic relationship between the occlusal surfaces of the teeth during function

Jaw function involves complex mandibular movement mediated by

muscles and nerves

Static occlusion was defined and classified by

Edward H. Angle

Today we use Angle's classification scheme to classify

static occlusion and malocclusion

The Angle Classification Method

Line of Occlusion

The alignment of the occluding surfaces of the teeth as viewed in the horizontal plane

Line of Occlusion: Maxillary arch

The central fossae of the molars and premolars

The lingual fossa of the canines and incisors

Line of occlusion: Mandibular arch

The buccal cusps of the molars and premolars

The cusps of the canines and incisal edges of the incisors

Describe the essential elements of Angle's "normal occlusion"

Meso-lingual cusp of maxillary 1st molar with central fossa of mandibular 1st molar

Mesio-buccal cusp of maxillary 1st molar aligned with buccal groove of mandibular 1st molar.

Both definitions are on slides

The angle classification method is based on the antero-posterior relationship of the permanent 1st molars viewed from the

buccal aspect

Definition of Class 1 molar occlusion

Mesio-buccal cusp of maxillary 1st molar aligned with buccal groove of mandibular 1st molar. This 1st molar occlusal relationship is the determinant of Class I normal occlusion and Class I malocclusion

Class I molar occlusion

Anything in the green is chillin though

Class III molar occlusion

Class II molar occlusion

When ideal contacts exist in a static relationship we have

normal occlusion

When ideal contacts do not exist in a static relationship we have a

malocclusion

Malocclusion

deviation from normal occlusion

Angle classified malocclusion as a

static relationship lacking ideal occlusal contacts which can occur with class I molar relationship and does not occur in Class II and Class II molar relationships

Angle Class I malocclusion

- Class I molar occlusion

- Any maxillary incisor inclination

- Any amount of central incisor overject

Angle Class II Division 1 Malocclusion

- Class II molar occlusion

- Central incisor proclined

- Increased central incisor overjet

Angle Class II Division 2 Malocclusion

- Class II Molar occlusion

- Central incisor retroclined

- Later incisors may be proclined or retroclined

Angle Class III Malocclusion

- Class III molar occlusion

- Any maxillary incisor inclination

- Any amount of central incisor overject

Go to timestamp 38:43 on the panapto

Trust me

Incisor overbite

Vertical relationship between the incisal edge of the maxillary central incisor and the incisal edge of the mandibular central incisors

- Given in a percent (Amount of the surface of the mandibular incisor crown that is covered by the maxillary incisor crown)

Deep vs Open overbite

Overjet

The horizontal overlap between the facial surface of the mandibular central incisor and the incisal edge of the maxillary permanent central incisor, measured along the occlusal plane