This is a prospective, observational, multicenter study designed to evaluate the real-world efficacy and safety of H42®, a collagen hydrogel, in the treatment of periodontal pockets. The study will include 153 observations related to 38 subjects (aged 18-65) undergoing periodontal treatment in routine clinical practice. H42® is intended for filling, reinforcing, and repairing periodontal pockets.

The primary objective is to evaluate the change in Periodontal Pocket Depth (PPD) from baseline to week 12.

Secondary objectives include assessing:

• Clinical Attachment Level (CAL): Calculated as PPD minus the distance from the cemento-enamel junction (CEJ) to the free gingival margin (FGM).
• Inflammatory Indices: Sulcus Bleeding Index (SBI), Bleeding On Probing (BOP), and Gingival Index (GI).
• Plaque Control: Plaque Index (PI) using the Silness and Löe scale.
• Patient-Reported Outcomes: Pain levels via a Numeric Rating Scale (NRS 0-10) and treatment satisfaction.
• Safety: Clinical assessment of infection (suppuration), Global Safety assessed by the Investigator (IGAS), and Global Safety assessed by the Patient (PGAS).

Participants undergo a baseline visit (V1) and six follow-up visits (V2-V7) over 12 weeks:

• V1 (Baseline): Mechanical instrumentation (scaling and root planing) followed by the application of H42® hydrogel (up to 5 pockets per patient). Baseline assessments include PPD, CAL, SBI, BOP, PI, GI, NRS pain, and radiographic imaging (X-ray or CBCT).
• V2, V3, V4 (Weeks 1, 2, 3): Evaluation of GI, pain (NRS), and presence of infection/suppuration.
• V5 (Week 4) & V6 (Week 8): Comprehensive periodontal assessment including PPD, CAL, SBI, BOP, PI, GI, and pain monitoring.
• V7 (Week 12 - End of Study): Final assessment of all periodontal parameters, radiographic imaging to measure pocket depth reduction, patient satisfaction survey, and global safety assessments (IGAS/PGAS).

Clinical photography is used throughout the study to support the evaluation of gingival inflammatory status.

Inclusion Criteria:

• Men or women with age between 18 and 65 years.
• Stage 3 generalized periodontitis
• Subjects affected by periodontal pockets with probing depth (PD) in the range between 5 to 8 mm
• For each subject a maximum of 5 defects were evaluated. If the patient presented more defects, at the beginning of the study the investigator identified the "target" lesions.
• Subjects who followed in the previous two weeks instructions to oral hygiene (proper brushing techniques twice a day, proper flossing technique daily).
• Subjects able to communicate adequately with the Investigator and to comply with the requirements for the entire study.
• The decision to prescribe H42® as an adjunctive therapy for the condition was entirely independent of that of including the patient in the study.
• Subjects or legal representatives had to be willing and able to give informed consent/assent for participation in the study.

Exclusion Criteria:

• Subjects presenting current or previous bleeding disorders.
• Subjects taking or having indications for anticoagulant therapy.
• Use of aspirin and antiplatelet agents within one week prior to treatment.
• Subjects with history of allergy or hypersensitivity to the tested device or to its ingredients, or hypersensitivity skin reaction to the investigational device, or at risk in term of precautions, warnings and contra-indications referred in the package insert of the clinical investigation device.
• Use of concomitant treatments or procedures aimed to improve gums health over the last six months before the clinical investigation enrolment, such as HA gel treatments, injection of fillers, surgery.
• Subjects unlikely to cooperate in the clinical investigation or with the clinical investigation visits.
• Pregnant or lactating women, or women of childbearing potential planning a pregnancy during the study.
• Subjects with illness, or other medical condition that, in the opinion of the investigator, would have compromised participation, or that would likely have resulted in hospitalization during the study (e.g., epilepsy), or predisposed to infections (e.g. HIV infection, acute hepatitis), or jeopardized the evaluation of the study results (e.g. herpes virus infection).
• Participation in an interventional clinical study or administration of any investigational agents in the previous 30 days.
• Any reason, according to Investigator's judgement, able to compromise compliance with procedures outlined in the study protocol or making participation in the study not advisable, was considered.

The dataset includes 153 observations related to 38 subjects, with multiple observations per subject due to different tooth positions. The study was conducted in two dental clinics located in Italy.