To describe specific locations on teeth, and in particular, the crowns of teeth, line angles, point angles and crown thirds are used. These are descriptive terms as teeth are not flat but generally convex or concave surfaces that join together seamlessly

Line Angles

A line angle is the area where two tooth surfaces join together. In the purest sense, a line angle is produced by two flat surfaces meeting. Teeth have curved surfaces using line angles helps in defining specific locations on the crown and root. Line angles are named by the joining of the two surfaces.

Point Angle

A point angle is the junction of three tooth surfaces and is named by the combination of the surfaces involved.



 Link to Video File 

Click on the movie icon above to view laine and point angles.


Crown thirds


All crowns can be divided into a cervical third and a middle third. All posterior teeth (premolars and molars) have an occlusal third while all anterior teeth (incisors and canines) have an incisal third.



 Link to Video File 

Click on the movie icon above to view crown thirds.


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