Relationship of gingival thickness and bleeding to loss of probing attachment in shallow sites following nonsurgical periodontal therapy

Periodontal sites of shallow initial probing depth often seem to lose probing attachment following various types of periodontal therapy, including nonsurgical therapy. The susceptibility to this treatment-associated probing attachment loss may conceivably be related to gingival architecture as well as to the inflammatory status of the tissues. This study was designed to study the relationship of buccolingual gingival thickness and bleeding on probing in shallow buccal sites (less than or equal to 3.5 mm probing depth) to loss of probing attachment following nonsurgical therapy. 3 months following treatment consisting of oral hygiene instruction and supra- and subgingival debridement, thin (less than or equal to 1.5 mm), initially non-bleeding sites displayed a mean loss of probing attachment of 0.3 mm. Thick (greater than or equal to 2.0 mm), non-bleeding sites displayed a less noticeable mean loss of probing attachment, whereas bleeding sites of both categories of gingival thickness showed a tendency towards gains in probing attachment levels. It may be concluded that the mean loss in probing attachment levels, commonly seen for shallow sites post-therapy, may be primarily due to the changes in shallow, thin healthy areas.