SEIBERT CLASSIFICATION

I

Horizontal

 

II 

Vertical

 

III

Mixed

 

 

 

 

ALLEN CLASSIFICATION

A

Horizontal

 

B

Vertical

 

C

Mixed

 

 

 

COLOGNE CLASSIFICATION

Orientation

Graft needs

Relation of graft to defect

 

 

CRITICAL SIZE DEFECT

When the implant is going to be placed entirely in grafted bone