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.
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