Normal Occlusion (Ortho 2 lec)

Ideal occlusion

is perfect occlusion, never attained in nature, and is a hypothetical goal for orthodontists.

Line of occlusion (Upper)

A smooth (catenary) curve passing through the central fossa of each upper molar and across the cingulum of upper canine and incisor teeth.

Line of occlusion (Lower)

A smooth (catenary) curve that runs along the buccal cusps and incisal edges of the lower teeth.

Lawrence Andrews

6 Keys to normal occlusion is defined by __ who studied 120 cases.

What are the 6 Keys to normal occlusion

1. Molar relationship

2. Crown angulation

3. Crown inclination

4. Rotations

5. Spacing

6. Occlusal plane

1. Mesiobuccal cusp of upper first molar occludes in the groove between mesial and middle cusps of lower first molar

2. Distal surface of distobuccal cusp of upper first molar occludes with mesial surface of mesiobuccal cusp of lower second molar.

What is the correct molar relationship?

Long axis of clinical crown (LACC)

Vertical line representing the __

LA spot

__ is the center of the long axis of

clinical crown LACC.

Crown angulation

Also known as mesio-distal tip

distal (+)

In crown angulation, gingival portion of LACC is __ to the incisal portion

+

In crown angulation, there is a __ reading if the gingival portion of LACC is distal to the incisal portion

-

In crown angulation, there is a __ reading if the gingival portion of LACC is mesial to the incisal portion

space

Increasing mesio-distal width occupies more __, which means that the patient will no longer undergo veneers because of the increased mesio-distal tip.

*An option to orthodontic treatment

5 degrees to the distal

For central incisors, how many degrees is the crown angulation?

9 degrees

For lateral incisors, how many degrees is the crown angulation?

11 degrees

For canines, how many degrees is the crown angulation?

2 degrees

For premolars, how many degrees is the crown angulation?

5 degrees

For molars, how many degrees is the crown angulation?

2nd order bend

What if hindi deretsyo ang premolar after orthodontic treatment, ano gagamiting order bend to upright itself?

1st order bend

Pag magkaiba yung labiolingual measurements ng incisor, ano ang gamit na order bend?

straight

Pag may tipping, use a __wire

True

(T/F) The degree of angulation depends on tooth type.

horizontal plane reference (Crown angulation)

is the line passing through LA spots

vertical plane reference (Crown angulation)

is perpendicular to the horizontal plane

Crown inclination

Refers to the labiolingual or buccolingual inclination of LACC

Crown inclination

expressed as + or - degrees, representing the angle formed by the line which is 90° to occlusal plane (OP) and a line tangent to the bracket site

lingual to incisal

In crown inclination, a + reading indicates if gingival portion of the tangent line or of the crown is __ to __ portion

+7 torque

In the crown inclination, there is a + reading when the gingival portion of the tangent line or of the crown is lingual to the incisal portion. What is the numerical value for that?

-7 torque

If the crown inclination is __, mawawala yung lip support kasi almost straight na sya.

labial to incisal

In crown inclination, a - sign indicates if gingival portion is __ to __ portion.

mesial/forward

In crown inclination (Anterior teeth), improperly inclined anterior crowns results in upper contact points being

__

distally

In crown inclination (Anterior teeth), properly inclined anterior crowns result in contact points move __, allowing normal occlusion.

tooth size discrepancy

In crown inclination (Anterior teeth), spaces resulting from normally occluded posterior teeth and insufficiently inclined anterior teeth are often blamed on __

lingual crown inclination

In crown inclination (Upper posterior teeth), from upper canine through the molars, there is __

canines to 2nd premolars

In crown inclination (Upper posterior teeth), the lingual inclination is constant/similar from __ to __.

molars

In crown inclination (Upper posterior teeth), there is a more pronounced lingual crown inclination in __

canines to 2nd molars

In crown inclination (Lower posterior teeth), lingual inclination progressively increases from __ to __

Rotations

The 4th key of occlusion states that there should be no __

premolars/molars

If there is a rotated __ it occupy more space in the arch.

Spaces; tight

In the 5th key of occlusion, there should be no __; contact points are __.

flat or slight curve of Spee

In the 6th key of occlusion, the occlusal plane should be __

intercuspation

In the 6th key of occlusion, __ is best when occlusal plane is flat.

Deep curve of Spee

This results in more contained area for upper teeth, making normal occlusion impossible

Reverse curve of Spee

Allows excessive space for each tooth to be intercuspally placed.

Retruded contact position (RCP)

It is the contact of teeth along the retruded path of closure

Retruded contact position (RCP)

It is the initial contact during closure around a transverse horizontal axis.

Intercuspal position (ICP) or Maximal intercuspal position (MIP)

Complete intercuspation of opposing teeth independent of condylar position.

*Hindi tinitignan dito yung centric relation or the condyle, that is the __

Intercuspal position (ICP) or Maximal intercuspal position (MIP)

Best fit regardless of condylar position.

MIP

Pag sa board exam ang question ay "teeth to teeth"

Centric relation (CR)

Maxillo-mandibular relationship independent of tooth contact

Centric relation (CR)

The condyles articulate in anterior-superior position against posterior slopes of articular eminence.

CR

Pag sa board exam ang question ay "bone to bone"

Centric relation

In __, tinitignan natin yung upper and lower teeth kapag naka-occlude. We look at the position of the condyle.

Centric occlusion (CO)

The occlusion of opposing teeth when the mandible is in centric relation

Centric occlusion (CO)

This may or may not coincide with the maximal intercuspal position

1-1.5 mm

In orthodontics, the CR and CO must be both correct. But for example, the CR is correct but in the CO there is a slight slide measuring __, it is still acceptable.

Canine guidance

a form of mutually protected articulation in which horizontal and vertical overlap of canine teeth disclude the posterior teeth in the excursive movement of mandible

*When you do lateral excursive movement, the posterior must be disoccluded.

Group function

If the patient has bruxism, they will not have canine guidance, instead, they have __

Group function

multiple contact relations between the maxillary and mandibular teeth in lateral movements on the working-side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces

Mutually protected articulation

An occlusal scheme in which the posterior teeth prevent

excessive contact of the anterior teeth in maximal

intercuspal position, and the anterior teeth disengage the

posterior teeth in all mandibular excursive movements.

Mutually protected articulation

Teeth of the anterior and posterior dentitions protect

each other during function

Anterior/Incisal guidance

When you protrude the lower jaw, the posterior is disoccluded and you will have __ guidance