Central Incisors
|
Maxillary Centrals |
Mandibular Centrals |
|
|
Contact |
Mesial: incisal 3rd, near edge Distal: near junct. Of incisal & mid 3rd. |
Both well within the incisal 3rd & at about same height. |
|
Crown |
Longest & widest of incisors. Longer than wide. |
5/8th the width of max. Very narrow. Symmetrical |
|
Incisal Angles |
Mesioincisal: about 90 degrees. Distoincisal: more rounded & obtuse. |
Distoincisal may be slightly rounded. However both basically 90 degrees. |
|
Incisal edge |
Slopes cervically distally |
|
|
Proportions |
Root slightly longer than crown. |
Root longer than crown, more so than max. |
|
Root shape |
As thick M.D. as F.L. Thick at cerv. 3rd. *not great anchor root due to conical/shortness. |
*Wider F.L. than M.D by 2.0 mm. |
|
Lingual fossae |
Less developeed than laterals. Can be shallow to deep. Deep w/ prominent marginal ridges are called shovel-shaped. |
Barely discernible. Lingual surface has concavity instead. |
|
Cingulum |
Well developed. Centered toward distal. Sits distal to the long axis. |
Small, centered & smoothe. |
|
Marginal ridges |
Prominent. Mesial longer than distal due to cingulum placement. |
Barely discernible |
|
Pits |
May possess where marginal ridges meet. Fossae contain pits. If pits than fossae are present. |
none |
|
Accessory lingual ridges |
May possess 1 to 4 |
none |
|
Root depression |
On mesial ONLY, runs longitudinally at junct of midddle & lingual 3rd. Mesial root is flattened. |
Roots flat. Both mesial and distal in middle 3rd. |
|
Incisal Edge |
1.5 to 2.0 mm. Slightly labial to long axis of root. *Distoincisal edge may be just lingual due to twisting. |
2.0 mm thick & runs straight. Lingual to the long axis of the root. |
|
CEJ |
More curvature on mesial than distal. |
Mesial curve (2.0 mm) more incisally than distal (1.6 mm). Only way to determine left from right. |
|
Height of contour |
Labial: cerv. 3rd just incisal to cervical line. Lingual: cervical 3rd. |
Labial: cervical 3rd. Note, labial surface can appear flat. Lingual: cervical 3rd. |
|
Crown width |
Wider M.D. than F.L. |
Wider F.L. than M.D. |
|
Crown outline |
Triangular, curved labially. |
Labial is slightly convex. |
|
Labial depressions |
Two |
Shallow, less pronounced |
|
Root Curvature |
Root tip may bend distally |