Dental Anatomy: Primary Dentition and parts of a tooth

Dental Anatomy is one of the most important classes of your first year. If you came into dental school knowing nothing about teeth like I did, then this is where you learn the basics of dentistry. It's important to have a strong foundation in this to pass your boards, do well in pre-clinical simulation lab, and to be a competent dentist!


I'm just going to go over the main sections here in case you were curious or just want a refresher.



Primary Dentition: 

- Deciduous, meaning it is meant to shed
- Considered the dentition of kids from 0 - 6 years old
- Starting at the most upper right tooth, which is a primary second molar, you number / letter that tooth 'A', then the tooth next to it which is a primary first molar, is 'B' and so on until you get to the most upper left primary second molar, which is 'J.'
- The two maxillary central incisors (two front teeth) are E & F.
- Then, continuing from J, you drop down t the opposing tooth of the upper left molar - the lower left primary second molar. That tooth is 'K'. Then you continue across the arch until you get to the lower right primary second molar, which is T.
- This system is referred to as Universal Numbering. Helpful hint: I always use my fingers when I'm counting! 

- Another system that we don't use that often in the US is the FDI system (also known as the International Dental Federation system). For Primary teeth, you would start at the midline (between the maxillary central incisors). The right incisor tooth is '51' and you count up until you reach the right second molar, which would be '55.' Then you start back at the midline, and the left incisor tooth is '61', and you count up until you reach the left second molar, which would be '65'. The bottom teeth order in a similar way, except you start with '71' on the lower left and '81' on the lower right.

- The last system you should know is the Palmer Notation System. This is more similar to the Universal System, but instead uses only 5 letters and indicates the location of the tooth with markings shaped like L's.




Parts of a Tooth: 

A: Apex (Plural apices) or the root tip(s)
AF- Apical Foramen
SC - Supplementary canal
B- Bone
C- Cementum
PM: Periodontal Ligament
PC: Pulp Canal
G - Gingiva
GC- Gingival Crevice
GM - Gingival Margin
PCH: Pulp Chamber
D: Dentin
E: Enamel
CR: Crown
CEJ: Cementoenamel junction. Separates the enamel of the crown from the cementum of the root and is where the gums start
PH: Pulp Horn
F: Fissure
CU: Cusp
BI: Bifurcation of roots