Premolars Flashcards
Function
Mastication
Maintains vertical dimension
Assist canines in shearing and cutting
Support cheeks
VDR-VDO=FWS
60-57=3 mm
Premolar loves
3 facial lobes
1 or 2 lingual lobes
Depends on 1 or 2 lingual cusps
Premolars general
CEJ still larger mesial but less curved
Roots taper apically and lingually
Marginal ridge horizontal
Facial in cervical third and lingual in middle third
Premolars buccal
Pentagon Distal contact is more cervical than mesial Except first mandibular premolars Mesial cusp ridge shorter than distal Except maxillary first premolars
Premolars lingual
Crown narrows Except 3 cusp types - 2 lingual cusp on mandibular 2 nd will make lingual wider Buccal cusp larger than lingual Lingual cusps go mesial Except mandibular first premolars
Premolars proximal
Mesial marginal ridge is more occlusal than distal
Except mandibular first premolars
Proximal contact follow the ridge pattern
Mandibular will have crown tilt lingual
Maxillary have crown over root axis
Premolars occlusal
Wider faciolingually than mesiodistally
Proximal contacts are Buccal to Buccalingual midline
Lingual embrasures are larger than Buccal
Triangular ridge form the transverse ridge
Except mandibular 2nd with 3 cusps and mandibular 1st with mesiolingual groove
Maxillary will have prominent Buccal ridge
Mandibular vs maxillary
Maxillary with prominent Buccal groove
Maxillary more rectangular
Mandibular more square bc Buccalingual greater distance
Maxillary cusps are larger and Buccal is larger
Maxillary 1st
Larger than second More convergent towards CEJ Wider shoulders Bifurcation of root possible Mesial contact is occlusal middle junction Distal contact is middle third MESIAL CUSP RIDGE IS LONGER THAN DISTAL Buccal Cusp is sharper Buccal ridge more prominent on first= larger notches than 2nd Shorter lingual than 2nd Lingual cusp to mesial Lingual root is shorter than Buccal Root crown ratio 1.56 MESIAL ROOT CROWN DEPRESSION has larger central groove= marginal groove mesial Larger than 2nd maxillary = squarer Hexagonal outline= Buccal ridge sharp line angle BUCCAL CUSP POINTS DISTAL
Maxillary 1st premolars
Smaller than 1st- smaller shoulders- less convergent crown
MESIAL contact on occlusal middle junction
Distal contact on middle third
Distal cusp ridge is longer than mesial- less sharp cusp
More likely to have one root
Cusps close to same height but Buccal larger
Lingual cusp sharper than first premolars
Lingual and Buccal cusp shifted mesial
Distal root depression bigger if any
Root to crown ratio 1.82
Smaller than 1st premolars
Central groove smaller than first
More supplemental grooves
More rectangle than all premolars
Pentagon shape occlusal
Less Buccal ridge than 1st maxillary premolars
Mandibular first premolars
Longer and wider crown than second, larger
Buccal cusp is shaper than 2nd mandibular premolars
Cusp facial notches are larger will have 2, mesial larger
MESIAL cusp ridge is shorter than distal
CEJ more curved than 2nd mandibular premolars
MESIAL CONTACT IS MORE CERVICAL THAN DISTAL
Marginal ridge shorter mesial than distal, only adult tooth
MESIAL contact is in middle third and distal is occlusal third
Tapper narrower to lingual
Lingual cusp is mesial center or distal
Mesiolingual groove
Crown axis tapers lingual more than 2nd mandibular premolars
CEJ is more occlusal on the lingual side than 2nd
Diamond shape occlusally, Buccal ridge pointer than 2nd
Snake eye lack central groove
Mandibular 2nd premolars
Shorter than 1st, less taper to CEJ
Buccal cusp is less dull
Distal notch can be seen sometimes
Mesial cusp ridge is shorter than distal
Less curves CEJ
Mesial and distal contacts in occlusal third
Larger root to crown ratio than first premolars
Lingual cusp is mesial to root axis
Can have 2 lingual cusp where distal is smaller
Central groove is U, Y, H shaped
Less crown taper to root axis than 1st
Can have marginal ridge groove
Lingual CEJ is more occlusal than Buccal
Square occlusal table possible triangular
Buccal ridge is smaller than all other premolars
