NBDE Part 1 – Dental Anatomy: Contact Points and Contour

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In this article, we give a complete and simpleifed guide to study the contact points and height of contour for dental anatomy section for the NBDE Part 1.

Contact Points and Contour

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Facts

  • Height of Contour (Crest of Curvature) : is an imaginary line encircling the tooth at the greatest bulge of the tooth.
  • They Form the Contact areas which the adjacent teeth contact each other mesailly and distally.
  • They Protects the surrounding givngiva, maintains hygiene and promote healthy gingiva.
  • They Prevent tooth rotation and medial drift from occurring and keeps the teeth stably positioned.
  • Thus its important to replicate the tooth contour on a dental crown to provide the same function as the natural contour.
  • Natural unworn contacts (help chewing) in the dental arch are
    • point-to-point.
    • point-to-area.
    • edge-to-edge.
    • edge-to-area.
    • Not Natural (may be due to bruxism): When area-to-Area contact occurs it leads to a scarping noise.
  • Cervical Line = CEJ (Cemento-Enamel Junction): is the line that separates the enamel from the cementum in other words separates the Anatomically Crown from the Anatomically Root.
  • The Direction of the Curvature is Towards the Apex on both the Lingual and Labial Side while towards the Occlusal/ Incisor Direction on both mesial and distal sides.
  •  Cervical Line has the Greatest curvature:
    • Upper Centrals have the Greatest Curvature.
    • Mesial Side has Higher curvature than Distal Side.
    • Anterior teeth > Premolars > Molars.

 

Facial View

I = Incisor 3rd / M = Middle 3rd / J= Junction between I and M

I = Incisor 3rd / M = Middle 3rd / J= Junction between I and M

  • All Mesial contacts are more Incisal/Occlusal than the Distal Contact.
  • The more posterior you move the more the contact point is towards the root direction.
  •  Lower centre has both contact points at the same level.Screenshot 2013-11-08 14.34.26

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The contact points are as following

contact upcontact down

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Occlusal view

  • All Teeth have there contact point Centred Faciolingual ( slightly buccal of the middle 3rd ). middle
  • 2nd premolar / 1st molar / 2nd molar contact point have a straight line that bisects every contact point.

teeth

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Side View

Side View ( C= Cervical 3rd / M = Middle 3rd)

Mesial View ( C= Cervical 3rd / M = Middle 3rd)

  • On the Facial side: height of contour of all teeth is at the Cervical 3rd.
  • On the Lingual side: height of Contour are:
    • Anterior Teeth: Cervical 3rd.
    • Posterior Teeth: Middle Third.

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About Author

Dr. Mohsen Saeed Ozaibi

A Dentist, Professional Blogger and Owner on OziDent.com. Graduated in 2009 with a Bachelor Degree in Dental Science from Misr International University. A Pioneer in Digital Dental Content Publishing.

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