Sutures are also classified by thread diameter:

Thread materials range in diameter from 1 to 10 with the higher number corresponding to the thinner, more delicate thread.

In implant dentistry a 3-0 thread diameter is usually used to secure flaps when a mattress suturing technique is placed.

4-0 thread is used to secure most other periodontal mucoperiosteal flaps.

 With periodontal plastic surgery a 5-0 thread diameter is most often used.