This study aims to evaluate the clinical results of non-surgical periodontal therapy performed with micro-instruments compared to traditional approach (standard curettes) after 6 months of follow-up.

The patients enrolled, subject to written informed consent, will be divided into a Test group (T) and a Control group (C) through a randomization process. Both groups will be motivated on the rules of oral hygiene, treated scrupulously and monitored monthly for 6 months, at the end of which the final data will be collected for statistical processing (in particular by analyzing the difference between baseline and after 6 months of the parameter "probing depth" or PD).

The aim of the study is to evaluate the clinical results of non-surgical periodontal therapy performed with micro-instruments (micro-curettes) compared to traditional instruments (standard curettes) after 6 months of follow-up.

The proposed clinical trial will be conducted according to the principles of the Declaration of Helsinki on experimentation involving human subjects.

All subjects will be recruited from the Area of Odontostomatology - Department of Neuroscience, Reproductive and Odontostomatological Sciences of the University of Naples "Federico II".

In a first phase, all patients will be treated with a supragingival scaling session in order to remove plaque and tartar and it will be provided instructions for a correct oral hygiene. After 1 week, the clinical parameters (PD, FMPS, FMBS, CAL, REC) will be recorded and the subjects randomly assigned to the Test (T) or Control (C) group.

In the Test group, after local anesthesia, subgingival mechanical debridement will be performed using an ultrasonic scaler with specific thin tips and Gracey micro-curette to minimize soft tissue trauma.

In the Control group, after local anesthesia, debridement will be performed using an ultrasonic scaler with specific thin tips and standard Gracey curettes.

At the end of the periodontal therapy, a polishing paste will be applied supragingival in both groups using a rubber cup. An antiseptic therapy based on mouthwash with chlorhexidine digluconate 0.12% (two rinses a day for the first two weeks) will then be recommended. No antibiotics will be prescribed.

Patients from both groups will be called up every month for a professional supragingival cleaning and professional motivation. The final evaluation will be carried out 6 months after the subgingival treatment.

Data analysis will be performed using statistical software (NCSS-PASS, NCSS, Kaysville, UT). The patient will be considered as a statistical unit; however an additional analysis based on the specific dental site will also be performed.

Inclusion Criteria:

• Untreated patients diagnosed with severe/advanced periodontitis with slow/moderate rate of progression
• Age > 18 years
• Patients at least 10 teeth per arch
• Presence at least of two teeth with PD > 5 mm per quadrant
• Single-rooted teeth or multi-rooted without furcation involvement

Exclusion Criteria:

• Patients with systemic diseases
• Pregnant or lactating
• Tobacco smokers (<10 cigarettes/day)
• Previous periodontal treatment in the last 2 years
• Prolonged antibiotic treatment or anti-inflammatory treatment within 6 months prior to periodontal therapy
• Furcation involvement
• Acute periodontal or endodontic abscesses
• Third molars