This randomized controlled trial adheres to the Consolidated Standards of Reporting Trials (CONSORT) 2010 guidelines and the Declaration of Helsinki ethical principles for medical research. The study complies with Good Clinical Practice (GCP) standards and will be prospectively registered with ClinicalTrials.gov to ensure transparency and accountability. A crossover design is implemented to ensure all participants receive both treatment modalities-microneedling (MN) alone and microneedling combined with injectable hyaluronic acid (MN + HA)-following an appropriate washout period, promoting equitable access while maintaining scientific rigor through within-subject comparisons.

Baseline Preparation

All enrolled participants receive comprehensive periodontal therapy at baseline, including supragingival and subgingival scaling using ultrasonic instrumentation combined with hand instruments. Standardized oral hygiene protocols are established with identical oral care products provided to each subject, including a soft-bristled toothbrush and interdental cleaning aids. All participants receive instruction in proper brushing technique with emphasis on twice-daily maintenance to ensure consistent plaque control throughout the trial.

Microneedling Intervention

The MN intervention comprises three sessions spaced seven days apart. Following baseline clinical assessment (plaque index, bleeding on probing, probing depth, clinical attachment level, keratinized tissue width, and gingival thickness) with standardized photographs, topical anesthesia is applied for one minute followed by infiltration anesthesia with 2% lidocaine with 1:100,000 epinephrine. The Dr. Pen Ultima A6 with a 24-pin cartridge is vertically inserted through keratinized gingiva until bone contact is achieved, treating from the mesial central incisor to the distal canine. Treatment ends when uniform pin-point bleeding is achieved. Post-procedure care includes gentle saline rinse, avoidance of brushing for 24 hours, twice-daily 0.12% chlorhexidine mouthwash for seven days, and avoidance of NSAIDs. Clinical reassessment occurs at 3 and 6 months.

Microneedling Plus Hyaluronic Acid Intervention

Following identical baseline assessment, anesthesia, and microneedling as the MN group, cross-linked hyaluronic acid (16-20 mg/mL, 200-400 µm particle size) is injected using 30-gauge needles (8 mm) with 1 mL insulin syringes. Two anatomical sites per area receive injections: 3 mm apical to the free gingival margin and apical to the mucogingival junction. The needle is inserted at 45 degrees, advanced 2-3 mm until blanching occurs, with a total volume of 0.04 mL per site (0.02 mL per point) at a rate not exceeding 0.01 mL per 10 seconds. Post-injection circular massage for 2-3 minutes ensures uniform distribution. Three sessions are performed seven days apart with identical post-procedure care and follow-up assessments at 3 and 6 months.

Outcome Measures

The primary outcome is the change in gingival thickness (millimeters) at treated sites from baseline to 6 months post-intervention, measured using transgingival probing. Secondary outcomes include changes in keratinized gingiva width, periodontal parameters (Plaque Index, Bleeding on Probing, Probing Pocket Depth, and Clinical Attachment Level), and patient-reported outcomes for pain, swelling, discomfort, and bleeding measured using visual analog scales at 2, 24, and 48 hours post-intervention. This comprehensive protocol ensures robust evaluation of both objective tissue augmentation and subjective patient experiences across both treatment modalities.

Inclusion Criteria:

• Adults aged ≥18 years from both sexes
• Systemically healthy individuals with no history of chronic systemic diseases.
• Participants with positive periodontal probe transparency in anterior teeth.
• Adequate oral hygiene (full-mouth plaque score ≤20%).
• Non-smokers or former smokers who quit ≥12 months prior to enrollment.
• Willingness to comply with study procedures, attend follow-up visits, and provide written informed consent.

Exclusion Criteria:

• Pregnancy or lactation.
• Use of medications affecting periodontal status or wound healing (e.g., systemic corticosteroids, bisphosphonates) within the past six months
• History of periodontal surgery or soft-tissue augmentation procedures at the target sites
• Active periodontal disease (probing depth >3 mm, clinical attachment loss >2 mm) or gingival inflammation (bleeding on probing ≥ 10%).
• Untreated carious lesions or periapical pathology in the study area.
• Systemic conditions that impair healing (e.g., uncontrolled diabetes mellitus, immunocompromised states).
• Use of anti-inflammatory or anticoagulant medications within two weeks prior to treatment.
• Known allergy to hyaluronic acid or components of the microneedling device.
• Presence of heavy gingival pigmentation at the target sites.

A double-blind design is implemented where both the outcome assessor and the statistician responsible for data analysis remain blinded to treatment allocation throughout the study. The outcome assessor, who is a calibrated examiner does not present during intervention procedures, performs all clinical measurements without knowledge of the interventions received at each site. Clinical measurements and standardized intraoral photographs are coded using an anonymous site numbering system without reference to actual treatments received. Similarly, the statistician remains blinded to treatment codes until completion of the final statistical analysis, with treatment groups coded using anonymous identifiers throughout data collection and analysis phases to prevent analytical bias