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

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

• 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.

The contact points are as following

Occlusal view

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

Side View

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.