Periodontal instrumentation aims to remove plaque and calculus from the root surface. Both manual and ultrasonic instruments have been used for such decontamination; however, establishing a healthy periodontium can result in adverse effects, such as dentin hypersensitivity. The aim of this study was to evaluate the effects of hand or ultrasonic instrumentation on dentin hypersensitivity in patients undergoing non-surgical periodontal treatment. For this controlled clinical trial of a "split mouth" design, 14 patients were selected with homologous teeth in the incisor to premolar region and probing depth ≥ 5 mm on the buccal aspect of the teeth. One side (control) was instrumented with hand instruments and the other side (test) with ultrasonic instruments. Dentin hypersensitivity was assessed in the baseline and during the follow 4 weeks after treatment, with a periodontal probe scratching the root surface and with an air jet. The patient's response was detected by a visual analog scale (VAS) of 10 cm.

Inclusion Criteria:

• patients diagnosed with chronic or aggressive periodontitis, according to the American Academy of Periodontology classification15, requiring non-surgical periodontal treatment in at least two quadrants. These quadrants should present two contralateral and homologous teeth in the incisor to premolar region with probing depth ≥ 5 mm and bleeding on probing on the buccal surface.

Exclusion Criteria:

• presence of systemic illness or medication use (six months preceding the research), which could influence the response to periodontal treatment,
• performance of periodontal treatment including subgingival instrumentation in the six months preceding the study,
• performance of treatment for dentin hypersensitivity in the three months previous to the study,
• presence of periapical or pulpal changes,
• being under orthodontic treatment,
• smoking and
• pregnancy.