HELLO

Menatalla M. Elhindawy

Morphology!!! A branch of biology that deals with the form and structure of animals and plants. The form and structure of an organism or any of its parts.

Maxillary Second Premolar

Where is it??

Is it a successor??

It is a successor..

It is a successor.. Do we have problems??

Max. 2nd premolar.. CHOROLOGY First evidence of calcification.. 2- 2 1\2 years.Enamel completed.. 6-7 years.Eruption.. 10-12 years.Root completion.. 12-14 years.

Max. 2nd premolar..In each aspect we need to full fill these requirements: Geometric outline.Outlines M., D., B., L., cusp. Contact areas or crest of curvatures.Surface anatomy.Cervical line.Root.

Max. 2nd premolar.. LABIAL ASPECT Geometric outline Trapezoidal.

II. OutlineMesial.. Slightly convex.Distal.. More convex.Cusp.. Short, less pointed and M. slop shorter then D. slop; tip is displaced to the M.

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Max. 2nd premolar.. LABIAL ASPECT III. Contact areas:M. at the junction bet. mid. and occ. 1\3s.D. at mid. of mid. 1\3.IV. Surface anatomy :Buccal and cervical ridges.V. Cervical line: convex root wise.VI. Root: single tapering from cervical to apical with a D. curved apecx.

Max. 2nd premolar.. LINGUAL ASPECT Lingual convergence.Reversed outlines.Lingual cusp is sharp, same length as buccal cusp.

Max. 2nd premolar.. MESIAL ASPECT Geometric outlinTrapezoidal.OutlinesBuccal and lingual .. Slightly convex.Cusps.. Almost same length; greater distance between cusps which widen the occ. Surface.

Max. 2nd premolar.. MESIAL ASPECT Crest of curtvture:Bucc. at junc. bet mid. and cervicalling.mid of the mid.IV. Surface anatomy : Aspect is smooth and convex with NO depressions. M. marginal ridge is more occ. than D. one.Contact area is broad. V. Cervical line: concave root wise.VI. Root: single; broad baccolingual with relatively blunt apex.Shallow developmental depression.

Max. 2nd premolar.. DISTAL ASPECT Similar to the M. aspect. D. contact area is wider and more cervical.D. marginal ridge is more cervical.Straighter cervical lines. Deeper developmental depression.

Max. 2nd premolar.. OCCLUSAL ASPECT Geometric outline: oval or rounded. Elevations: Cusps.. Both at the same size with wide distance inbetween.Marginal ridges.. thick, strong and well developed

Max. 2nd premolar.. OCCLUSAL ASPECT Depressions: Central groove.. Short with multiple supplemtal grooves.Triangular fossae: near to each other; D. is larger and deeper than M.

Any questions??

Now Lets compare 1st and 2nd maxillary premolars

Lets compare..1st premolar Buccal aspect 2nd premolar Buccal aspect

Outlines:M. concave; D. less concaveCusp: M. slop longer than D.; tip is displaced to D.Contact areas:M. Just occ. to the mid. of the mid.1\3; D. at the junc. bet. mid. and occ. 1\3s

Outlines:M. slightly convex ; D. convex Cusp: M. slop shorter than D.; tip is displaced to M.Contact areas:M. at the junc. bet. mid. and occ. 1\3s; D. at the mid. of the mid.1\3;

Lets compare..1st premolar Lingual aspect 2nd premolar Lingual aspect Lingual cusp.. Shorter 1 mm than buccalTip displaced to M. Sharp although the whole ling. surface is convex.

Lingual cusp.. same length as the buccal.Sharp.

Lets compare..1st premolar Mesial aspect 2nd premolar Mesial aspect Surface anatomy..Canine fossa.Mesial marginal developmental groove.Root..Bifurcation level mid root.Developmental depression.

Surface anatomy.. smooth and convex with no depressions. Root..Single; broad.Developmental depression.

Lets compare..1st premolar Distal aspect 2nd premolar Distal aspect Surface anatomy..No canine fossa.No mesial marginal developmental groove.Root..Bifurcation level at the apical 1\3.

Surface anatomy.. similar to M. aspect. Root..Single; broad.Deeper developmental depression.

Lets compare..1st premolar Occlusal aspect 2nd premolar Occlusal aspect Outline.. Hexagonal.Elevations.. Cusps.. Buccal and lingual.Marginal ridges.. Depressions..Long central grooveNo supplementary ones.Mesial marginal developmental groove.2 triangular fossae.

Outline.. Oval or roundedElevations.. Cusps.. Buccal and lingual.Marginal ridges.. Thicker ones Depressions..short central grooveSupplementary ones.2 triangular fossae.

Any questions??

Thank you