Lecture # (5)
Sheet written by Majdi Salameh
* Permanent maxillary lateral incisor :
- Sometimes the Cingulum is so large that they call it Talon Cusp. Talon Cusp is mostly found in permanent maxillary lateral incisor but rarely found in primary teeth . ( Talon Cusp : is a very enlarged cingulum and sometimes looks like a separated cusp ) . - The Peg shaped lateral incisor : instead of having a normal incisal edge .. the tooth is found pointed .. but it is unlike the Canine .. because the Canine tip is in the middle of the tooth ... In the peg shape, the tip is located in the mesial side of the tooth . - palatogingival groove : It starts from the lingual fossa , it interrupts the cingulum and it continues for a distance in the root surface.
- Tuberculum dentale : It is a cingulum enlarged a little bit and smaller than the Talon cusp . If it gets really large it's called Talon cusp but as long as it is small in size it's called Tuberculum dentale .
Labial Aspect :
- Mesial contact point location is higher than its location in the Maxillary Central incisor ... the location of the mesial contact point of the maxillary lateral incisor is on the junction between the incisal and middle third , where its location in Maxillary Central incisor is within the incisal third near the incisal edge .
- Distal contact point location is in the middle of the middle third (which means that it's in the middle of the crown ).
- Outlines are generally more rounded in the lateral incisor than the central incisor .
- Cervical line is more convex .
- The lateral incisor is smaller in all dimensions than Central incisor except in root length which they're in both the same length
- Mesial incisal angle is rounded and not sharp . Distal incisal angle is even more rounded .
- Mesial and distal outlines are convex .
- The apex in the lateral incisor root is more pointed than the apex in the central incisor .
- The root deviate toward the distal . But this is not a standard . That means the root can be centered sometimes or it even can be inclined mesially . But it's most common inclined distally .
Lingual Aspect :
- There are more chances to see pits and developmental grooves in the lingual aspect more than any aspect in the lateral incisor .
Mesial Aspect :
- Mesial aspect in the lateral incisor is similar to the mesial aspect of the central incisor in shape , because they're both Triangular in shape .
- Cingulum is more convex because it's more pronounced .
Incisal Aspect :
- We don't see full convexity on the labial side .
- Mesial side is convex . But the distal side has a slight depression which makes it more similar to the canine .
- The Lateral incisor is smaller mesio-distally and Labio-lingually than the central incisor .
- Labial outline is rounded in the mesial half, In the distal half there's a depression .
*Permanent Mandibular incisors :
- Crown : labio- lingually diameter is almost the same with Maxillary permanent incisors . But mesio-distally is smaller .
- Root : Cross section in Mandibular permanent incisors root shows that the shape of the root is Oval or Ovoid or Oblong .
- Cross section in Maxillary permanent incisors shows that the shape of the root is Triangular .
- Type traits : Mandibular lateral and central incisors are nearly the same in the size of Crown .. but the lateral crown is slightly larger than the central incsior crown. And also the root of the lateral incisor is slightly longer than the root of the central incisor .
Mandibular Central Incisor :
Labial Aspect :...