
* A single bilateral edentulous area crossing the midline.

* Class I :Bilateral edentulous area most posteriorly . Mod 2 : two extra edentulous areas

* Class III- Edentulous area present between anterior and posterior natural teeth posteriorly. Mod I : one extra edentulous space

* Unilateral Edentulous area

* Bilateral Edentulous area

* Edentulous area between anterior and posterior natural teeth

* Class II : unilateral edentulous area present from most posteriorly. Mod 2: Extra 2 edentulous space

* Class III- Edentulous area present between anterior and posterior natural teeth. Mod 1 – one extra edentulous space present.
Reference : Google pictures