What is a likely reason for a 1-2mm reduction in probing depth after scaling and root planing (SRP)?

A 1-2mm reduction in probing depth after scaling and root planing (SRP) is primarily associated with decreased pocket inflammation. The goal of SRP is to remove bacterial plaque, calculus, and other debris from the tooth surfaces and underlying tissues that contribute to periodontal disease. Following SRP, the inflammatory response in the tissues typically reduces, leading to a decrease in edema and inflammation surrounding the periodontal pockets.

As inflammation resolves, the tissues begin to heal, and the sulcular epithelium can reform into a healthier state. This healing is evidenced by reduced probing depths, as the tissue may return to a more physiologically normal state without undue inflammation. While other factors like improved oral hygiene can contribute to pocket depth changes, the direct link between SRP and reduced inflammation is the primary reason for the observed decrease in depth.

The formation of long junctional epithelium and recession of gum tissue, while relevant to periodontal healing, typically do not account for such an immediate and predictable reduction in probing depth as seen with decreased inflammation. Furthermore, improved oral hygiene is essential for maintaining health post-SRP but does not directly produce the initial immediate effects seen after the procedure itself. Hence, the most likely reason for the reduction in probing depth is