Maxillary first premolar Flashcards

1
Q

Posterior Teeth

A

Include:

1st and 2nd Pre-Molars, as well as the 1st, 2nd, and Third Molars

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2
Q

Characteristics of Posterior Teeth

A
  1. Greater relative faciolingual measurement compared with mesiodistal
  2. Broader contact areas- thick
  3. Contact areas are more nearly at the same level
  4. Less curvature of the cervical line and mesially and distally
  5. Shorter crown crevico-occlusally than that of anterior teeth- low to the floor
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3
Q

Pre Molars in General

A

4 in each arch, replace the deciduous molars (thus, no pre molars in primary dentition)

  • Bicuspid= two cusps
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4
Q

Mandibular Pre Molar variation in cusps

A

can range from 1-3 cusps

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5
Q

Where are the cusps and roots located?

A

They’re placed buccal and lingually, roots are also placed buccal and lingually

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6
Q

Which cusp of a max and mand 1st premolar is long and sharp?

A

Buccal cusp of the max and mandibular is the longest and sharpest. Similar to how the neighboring canine has that one cusp that is apprehensive for prehensile/tearing tooth

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7
Q

How is the buccal cusp of the max and mand 2nd premolar?

A

It is less sharp and in articulation with the opposing teeth making them more efficient and grinding like molars

KEY NOTE: THE BUCCAL CUSP IS LIKE THE CUSP OF A CANINE

WHILE THE LINGUAL CUSP IS MORE LIKE THE SURFACE OF MOLARS

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8
Q

What type of plane do the marginal ridges exist in?

A

They exist in more of a horizontal plane!, as part of the occlusal surface, instead of part of the lingual surface like anterior teeth.

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9
Q

Facial Aspect

A

Mesial- Middle Third
Distal- Middle Third

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10
Q

Proximal Aspect

A

Buccal- Cervial Third
Lingual- Middle Third (note that because the lingual cusp is shorter)

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11
Q

Occlusal Aspect

A

Occlusal Aspect
Mesial- junction of the middle and buccal third
Distal- middle third

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12
Q

Occlusal Aspect

A

Buccal- Middle Third
Lingual- Middle Third

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13
Q

First calcification

A

1.5-1.75

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14
Q

enamel completion

A

5-6 years

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15
Q

eruption

A

10-11 years

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16
Q

root completion

A

12-13 years

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17
Q

Measurements

A

Mesial distal crown width is shorter than the facial lingual crown length.

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18
Q

Roots

A

Usually have two, with two pulp canals!

If one root is present there are usually still two canals!

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19
Q

How many lobes do the maxillary 1st premolar develop from?

A

Develop from the 4 lobes just like anterior teeth, main difference is a well-formed lingual cusp, from the lingual lobe.

Crowns are shorter than the canines

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20
Q

Is the mesial cusp ridge of the buccal cusp longer than the distal cusp ridge?

A

The mesial cusp ridge is longer than distal cusp ridge. OPPOSITE of maxillary canine and opposite of the maxillary second premolar

NOT as wide mesiodistally as maxillary canine

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21
Q

What is the crown shape of a maxillary 1st premolar?

A

The crown shape is a trapezoidal shape

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22
Q

How is the mesial outline on the buccal aspect?

A

The mesial outline is slightly concave near the CEJ to the mesial contact area, and the mesial contact area is a relatively broad curvature.

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23
Q

Mesial Contact Area

A

In the Middle Third, is a relatively broad curvature, the crest of which immediately occlusal to the halfway portion from the CEJ to the tip of buccal cusp.

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24
Q

Mesial Buccal Cusp Ridge

A

IS STRAIGHTER AND LONGER than distal.

Distal cusp ridge is more round and shorter.

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25
Q

Can the mesial slope of the buccal cusp sometimes be notched or have an appearance of a concave outline?

A

YES

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26
Q

You draw a bisecting line down, where does the tup of the buccal cusp relate to bisecting line on the buccal surface of the crown?

A

It is located distally!

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27
Q

Distal Outline on Buccal Aspect

A

Distal outline from CEJ to height of contour is straighter than mesial but also may be concave,

Focus more on the distal contact area is represented by a BROADER curvature!

28
Q

Which lobe is more defined, gives a convex appearance?

A

Middle Buccal Lobe

29
Q

Buccal Ridge

A

From the buccal cusp tip to the CEJ on the buccal surface of crown!

30
Q

Are there developmental depressions on the mesial and distal surfaces of the buccal ridge?

A

YES- found in the occlusal thirds!

31
Q

Roots longer or shorter than the maxillary canine?

A

SHORTER

32
Q

Lingual Aspect

A

Crown tapers to the lingual because lingual cusp is narrower mesiodistally than the buccal cusp.

Both cusps are visible from this view!

CEJ has a greater curvature towards apex than on the buccal aspect.

33
Q

Mesial Aspect Shape

A

Trapezoidal in shape- the horizontal line across the cervix is longer than a horizontal line drawn at the cusp tips.

34
Q

Curvature of the CEJ

A

Still greater on the mesial, but not as defined as compared to anterior teeth.

35
Q

Buccal outline from the mesial aspect

A

Curves outward from the CEJ to the height of contour, and then extends to cusp tip with less convexity.

36
Q

Height of Contour on the Buccal Surface

A

At the junction between the middle and gingival/cervical third, or within the gingival third!

37
Q

Is the buccal cusp tip inline with the middle of the buccal root?

A

YES

38
Q

Lingual Outline on Mesial Aspect

A

smooth curved line starting on the CEJ and ending on the lingual cusp tip.

39
Q

Crest of Curvature of lingual

A

Is at the MIDDLE 3rd!

40
Q

Where does the mesial marginal ridge sit?

A

On the junction of the middle and incisal third!

41
Q

Mesial marginal developmental groove

A

Extends across the mesial marginal ridge onto the mesial proximal surface directly lingual to the mesial contact area

42
Q

Mesial developmental depression

A

Sits cervical to the mesial contact area, centered on the mesial proximal surface and bordered bucally and lingually by mesiobucacal and mesiolingual angles.

Even with one rooted 1st premolar the root depression is VRY NOTICEABLE for most of root length!

43
Q

Buccal Outline from the Mesial aspect

A

Relatively straight compared to a lingual inclination

Once the root bifurcates, the root may have a buccal curve in which the buccal outline is straight from CEJ to apex or buccal curve in the middle third root.

Lingual root is relatively straight but may curve towards the buccal or lingual

44
Q

Mesial Aspect: What makes up about 1/2 the root length in the bifurcated root?

A

Root Trunk

45
Q

What is the mesial marginal ridge rule on max 1st and 2nd premolars?

A

Mesial marginal ridges are more occlusal than the distal marginal ridge

46
Q

Distal Aspect

A

-Crown surface is convex at all points except for a small, flattened arc cervical to the contact area and buccal to the center of distal surface.

CEJ has less curvature

47
Q

Is there a distal marginal developmental groove?

A

NO

48
Q

Is the root trunk flat without a development depression on the distal side?

A

YES

49
Q

What is the shape of the crown on the occlusal aspect?

A

Irregular Hexagonal Shape
- Wider on the Buccal than the Lingual

50
Q

The crest of the buccal ridge in comparison to the crest of the lingual ridge?

A

DISTAL to

51
Q

The crest of the buccal ridge in comparison to the crest of the lingual ridge?

A

DISTAL to

52
Q

Mesial Contact area is _______ to the distal contact area

A

Lingual

53
Q

Buccal cusp tip

A

Distal on a bisecting line

54
Q

Mesiobuccal cusp ridge longer or shorter than distobuccal ridge?

A

Longer

55
Q

TRUE OR FALSE: ALL other premolars have a buccal cusp slightly MESIAL to a bisecting line

A

TRUE- in this case- the max 1st pre molar has buccal cusp tip to the Distal

56
Q

Where is the lingual cusp tip located in regards to a bisecting line?

A

MESIAL for both maxillary premolars

57
Q

What is circumscribed by the cusp ridges and marginal ridges?

A

the occlusal surface– aka the occlusal table

58
Q

Occlusal Table

A

Buccal cusp tip
Mesiobuccal cusp ridge
Mesiomarginal ridge
Mesiolingual cusp ridge
Lingual cusp tip
Distolingual cusp ridge
Distal marginal ridge
distobuccal cusp ridge
buccal cusp tip`

59
Q

What is more visible from the occlusal view- buccal surface or lingual surface?

A

Buccal Surface

60
Q

Are there any supplemental grooves visible?

A

NO- relatively smooth occlusal surface then

61
Q

What divides the surface evenly buccolingually?

A

Central Developmental Groove

62
Q

What is near the distal marginal ridge?

A

The distobuccal developmental groove that joins the central groove

63
Q

What comes off the central groove that extends towards the mesial aspect of the buccal surface?

A

mesiobuccal developmental groove

64
Q

True or False: The mesial side of the central groove joins the mesial marginal developmental groove, which crosses the mesial marginal ridge and ends on the mesial surface?

A

True

65
Q

What happens at the junction of these grooves?

A

They are deep and referred to as the mesial and distal developmental pits

66
Q

What surrounds these pits?

A

Two depressions on the occlusal surface around these pits are called the mesial and distal triangular fossa.