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

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

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.

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