Define The figure of 8 and Mattress suturing techniques

The figure of 8:  is placed similarly to the simple loop on the buccal aspect; however, on the lingual aspect, the needle penetrates through the outer, not inner, surface of the lingual flap.

Mattress suturing techniques: generally are used to resist muscle pull, evert the wound edges (this keeps epithelium away from underlying structures), and to adapt the tissue flaps tightly to the underlying structures. these can be classified as vertical mattress and horizontal mattress