• Pocket depth is the distance between gingival margin to the base of the pocket (or coronal end of junctional epithelium).
• Pocket depth of 6mm means distance between gingival margin and base of sulcus is 6mm.
• Level of attachment is the distance between CEJ and the base of pocket.
• Pocket depth is less important than level of attachment because it is not necessarily related to bone loss.
• A tooth with deep pockets may have little bone loss while a tooth with shallow pockets may have severe bone loss.
• Prognosis is considered as poor if the base of the pocket is close to root apex.
• In a pseudo pocket or gingival pocket there is no attachment loss.
• The pocket depth is due to the coronal movement of gingival margin.

• In a true pocket there is apical movement of the junctional epithelium due to the destruction of the supporting tissues.
• In supraboney pockets the base of the pocket is coronal to the underlying alveolar bone.
• Psuedopocket forms when there is deepening of the sulcus due to gingival growth rather than the displacement of junctionally epithelium apically.
• If gingival margin is on anatomic crown then level of attachment = pocket depth – distance from CEJ to gingival margin.
• If gingival margin coincides with CEJ the level of attachment = pocket depth
• If gingival margin is apical to CEJ then level of attachment= pocket depth + distance from CEJ to gingival margin

One walled pocket means only one wall of the pocket is present(hemiseptum) or three sides bone destruction is there.
• Three walled pockets or infrabony pockets have only one side bone loss, well supported by the bone on the other three sides.