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NCT Number: NCT07061756

Nd:YAG Laser Effects on Subgingival Microbiota in Stage III-IV Periodontitis

This randomized controlled trial (RCT) aims to evaluate the clinical efficacy of Nd:YAG laser adjunctive therapy and its impact on the subgingival microbiome in patients with stage III-IV periodontitis. The study addresses two key questions: (1) Whether Nd:YAG laser combined with scaling and root planing (SRP) yields significantly greater improvements in periodontal parameters compared to SRP alone; and (2) How subgingival microbial dynamics correlate with therapeutic outcomes.

Participants were randomized into two groups: the SRP group (mechanical debridement only) and the Nd group (mechanical debridement with Nd:YAG laser therapy). Clinical parameters-including probing depth (PD), clinical attachment level (CAL), and gingival index (GI)-were assessed at baseline and 3 months post-treatment. Subgingival plaque samples were analyzed via 16S rDNA sequencing to characterize microbial community shifts.

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Key information

Conditions

Periodontitis Mouth Diseases Periodontal Diseases Stomatognathic Diseases

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The First Affiliated Hospital of Sun Yat-sen University

Guangzhou, Guangdong, 510000, China

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged 18-80 years
  • Minimum of 14 remaining natural teeth
  • Diagnosis of Stage III-IV periodontitis according to the 2018 World Workshop classification system
  • No periodontal treatment within the past 6 months
  • Willing to provide informed consent and participate in the study protocol

Exclusion criteria

  • Presence of systemic conditions that may affect periodontal treatment outcomes (e.g., uncontrolled hypertension [>140/90 mmHg], diabetes mellitus [HbA1c >7%])
  • Use of antibiotics or medications known to induce gingival enlargement (e.g., calcium channel blockers, phenytoin) within the past 3 months
  • Coagulation disorders or hematologic diseases
  • Active systemic infections
  • Pregnancy or lactation
  • Acute periodontal lesions
  • Inability to comply with study protocols

Treatment and study plan

SRP

Procedure

Full-mouth scaling and root planing (SRP) was performed using an ultrasonic scaler (EMS AIR-FLOW MASTER PIEZON®) supplemented by Gracey curettes for subgingival instrumentation. All procedures were conducted under local anesthesia by a calibrated periodontist, with each quadrant treated for a minimum of 30 minutes. Patients received standardized oral hygiene instructions and were scheduled for a 3-month postoperative follow-up.

ND

Procedure

In addition to the identical SRP protocol described above, adjunctive Nd:YAG laser therapy (Wiser Waterlase MD, Vista Dental) was applied immediately post-SRP. Laser parameters were set at 150 mJ/pulse, 20 Hz frequency with water (level 1) and air (level 3) coolant. The fiber optic tip (300 μm diameter) was moved in a continuous "Zig-zag" pattern along the root surface and pocket epithelium, maintaining 2-second irradiation per site at a 30° angle to the tooth axis. Standardized oral hygiene instructions and 3-month follow-up were similarly provided.

Primary outcomes

  1. Alpha diversity of subgingival microbiota

    Time frame: From enrollment to the end of treatment at 3 months

    The higher the alpha diversity, the greater the species richness and evenness of the microbial community.

  2. Probing Depth

    Time frame: From enrollment to the end of treatment at 3 months

    Probing depth (PD) measures the distance from the gingival margin to the base of the periodontal pocket, clinically assessing periodontal attachment loss and tissue destruction.

Secondary outcomes

  1. Beta diversity of subgingival microbiota

    Time frame: From enrollment to the end of treatment at 3 months

    Beta diversity reflects the similarity in species composition.

  2. Composition of subgingival microbiota

    Time frame: From enrollment to the end of treatment at 3 months

    The composition of subgingival microbiota refers to the taxonomic structure and relative abundance of bacterial species within the periodontal pocket biofilm, which plays a critical role in periodontal health and disease progression.

  3. Microbial phenotypes of subgingival microbiota

    Time frame: From enrollment to the end of treatment at 3 months

    The microbial phenotypes of subgingival microbiota encompass the functional and metabolic characteristics of periodontal biofilm communities, including virulence factors, antibiotic resistance profiles, and synergistic interactions that contribute to periodontal pathogenesis.

  4. Clinical Attachment Level (CAL)

    Time frame: From enrollment to the end of treatment at 3 months

    Clinical Attachment Level (CAL) measures the distance from the cementoenamel junction (CEJ) to the base of the periodontal pocket, directly quantifying periodontal tissue destruction and tooth-supporting structure loss.

  5. Gingival Index (GI)

    Time frame: From enrollment to the end of treatment at 3 months

    The Gingival Index (GI) assesses the severity of gingival inflammation through standardized scoring of redness, swelling, and bleeding tendency, providing a quantitative measure of periodontal tissue health.

  6. Plaque Index (PI)

    Time frame: From enrollment to the end of treatment at 3 months

    The Plaque Index (PI) quantifies the extent of bacterial plaque accumulation on tooth surfaces, using standardized scoring systems to assess oral hygiene status and periodontal disease risk.

  7. Bleeding on Probing (BOP)

    Time frame: From enrollment to the end of treatment at 3 months

    Bleeding on Probing (BOP) evaluates gingival inflammation by recording the presence/absence of bleeding within 30 seconds after gentle periodontal probing, serving as a key diagnostic indicator of active periodontal disease.

Sponsors and collaborators

Lead sponsor

Rui He

Other

Registry information

Official study title

Characteristics of Subgingival Microbiota in Patients With Stage III-IV Periodontitis in Response to Nd:YAG Laser-Assisted Therapy

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Jul 11, 2025
Registry last updated
Jul 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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