Premolars O 8 Premolars O Teeth Anterior To Molars O

PREMOLARS o 8 premolars o Teeth anterior to molars o Also known as BICUSPIDS (2 cusps) o Erupts at age 10-12 and erupts ahead of maxillary permanent canine CLASS TRAITS 1. have at least 2 cusps, but may have additional cusps 2. have single buccal cusp with one or more lingual cusps ARCH TRAITS o FACIAL VIEW OF MAXILLARY PREMOLARS 1. have 2 major cusps which are approximately equal in size 2. buccal cusp is almost the same size as lingual cusp 3. crown is wider Bu-Li than M-D o PROXIMAL VIEW OF MAXILLARY PREMOLARS 1. buccal profile only shows a slight Li inclination because they are trapezoid 2. height of contour of the Li profile is at the mid portion of the crown 3. greater morphological similarly between maxillary premolar o FACIAL VIEW OF MANDIBULAR PREMOLARS 1. Bu is bigger than Li cusp 2. Crown has almost equal Bu-Li & M-D dimensions 3. Bu profiles are strongly inclined lingually o PROXIMAL VIEW OF MANDIBULAR PREMOLARS 1. shape is rhomboidal 2. Li height of contour is at the occlusal third of the crown TYPE TRAITS

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crown profile is HEXAGONAL 2. Mesiobuccal(MB) & Distobuccal(DB) corners are sharp 3. M & D profiles converge Lingually 4. Occlussal table outline is trapezoidal (where it meets its antagonist) 5. Buccocervical Ridge (BCR) are longer (BP longer, MP shorter, DP longer, LP shorter) 6. BCR oriented ML, twisted appearance 7. BC wider than LC 8. CG is long 9. Supplemental Grooves are rare 10. Bu, Central and MMG form characteristic patterns 11. Bu Ridge and lobes visible MESIAL DEVELOPMENTAL DEPRESSION – concavity within the mesial surface CONTACT AREA: JUNCTION OF OCCLUSAL & MIDDLE THIRD *MMR more occlusally positioned *DMR more cervically positioned * All MMR are occlusally positioned except for MANDIBULAR 1st PM

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MAXILLARY 1ST PREMOLAR BUCCAL VIEW

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More angular than Maxillary 2nd Premolar 2. Prominent bulging shoulders because Mesial Occlusal Angle and Distal Occlusal Angle have angular bulging shoulders 3. Mesial Contact Area – junctioning the Occlusal and Middle Thirds 4. Distal Contact Area – more cervical but still within the middle thirds 5. Prominent Bu cusp ridge  LINGUAL VIEW 1. entire buccal profile of crown is visible 2. apex of lingual root are more blunt 3. 2 root apices are visible Bu root is slightly longer 4. Li cusps are slightly mesial to the middle of the crown PROXIMAL VIEW 1. Mesial Marginal Groove (MMG) interrupts the Mesial Marginal Ridge (MMR) 2. 2 roots – Bu & Li 3. Lingual profile is straight

TRAPEZOIDAL in shape 5. Bu cusp tip is in line with the root apex 6. Li cusp tip is in line with the border of the Li root 7. root trunk is very long 8. cervical lines are flat OCCLUSAL VIEW

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MAXILLARY 2ND PREMOLAR BUCCAL VIEW 1. Crown has narrow shoulders 2. Crown is smallest in width and height 3. Mesial Occlusal Angle and Distal Occlusal Angle are less prominent and angular 4. lobes are absent 5. Bu cusp are not so prominent LINGUAL VIEW 1. none of the Bu profile is visible 2. portion of the Mesial concavity can be seen in the apical area of the root PROXIMAL VIEW 1. no MMG crossing the MMR 2. single root 3. BC and LC have the same height 4. root apex bends toward the D 5. MMR occlusally positioned; DMR cervically positioned OCCLUSAL VIEW 1. crown profile OVOID 2. MB & DB corners are rounded 3. no Li convergence 4. M & D profiles are parallel 5. Occlusal table outline is RECTANGULAR 6. M& D are parallel to each other and not inclined 7. crown is not twisted in appearance

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BCR is centered BC & LC similar in width CG is short Supplemental Grooves are frequent and numerous 12. Bu ridge and lobe not prominent *WRINKLED PREMOLARS – MAX 2nd PM

-Rosette Go 081808 