Impact of improved oral hygiene before nonsurgical periodontal instrumentation on clinical parameters and soft-tissue topography of randomly selected quadrants

To assess the effect of improved oral hygiene (OH) before nonsurgical periodontal instrumentation on soft-tissue topography in patients with advanced periodontitis. Ten systemically healthy patients with generalized periodontitis stage II/III grade C were enrolled. All received OH instruction and motivation. Supragingival and subgingival instrumentation was performed in randomly selected quadrants (split-mouth design), followed by treatment of the remaining quadrants 3 months after. Clinical parameters and intraoral scans (IOS) were obtained at baseline and 3 months after instrumentation. Surface deviations between the scans were assessed after manual prealignment and local best fit of canines and selected molars. Using color maps, deviations were categorized into four intervals: 0.5 to 1.0, 1.0 to 1.5, 1.5 to 2.0, and >2.0 mm. The surfaces of each deviation intervals were calculated. All patients maintained full mouth plaque score (FMPS) <20% after first instrumentation. Significant improvements in probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP) were observed in quadrants with improved OH before instrumentation. A 1.24 grater CAL gain was measured in sites with initial PPD ≥6 mm (p=0.002). Surface changes were two times greater (1–1.5 mm interval), 3.5 times greater (1.5–2 mm interval), and eight times greater (>2 mm interval) in quadrants instrumented before OH improvement. However, changes were not statistically significant. Improved OH before nonsurgical periodontal instrumentation significantly enhanced clinical outcomes, particularly in deeper pockets. Although smaller soft-tissue surface changes were measured, they did not reach statistical significance.