Short-Term Changes in Salivary IL-6, TNF-α, and Periodontal Inflammation Following Sleeve Gastrectomy in Patients With Obesity: A Randomized Controlled Pilot Study

This randomized, controlled, prospective, longitudinal pilot study used two parallel groups. Adults aged 18-65 years with severe obesity and stage I-III periodontitis were enrolled at the 2nd Department of Surgery at the Emergency County Clinical Hospital of Targu Mures, Romania, and associated private practices. After eligibility confirmation, baseline full-mouth periodontal examination, anthropometric assessment, and unstimulated saliva collection, participants were randomly assigned to laparoscopic sleeve gastrectomy (SG) or non-surgical management (NSG). The allocation sequence was generated using a computer-based random-number procedure by an investigator who was not involved in periodontal examination or laboratory analysis. Assignments were placed in sequentially numbered, opaque, sealed envelopes and opened after completion of baseline measurements. Randomization was simple and used no blocking or stratification. Participants and treating clinicians were not blinded.

Assessments occurred at baseline, 3 months, and 6 months. Baseline was the preoperative visit for SG participants and the enrollment visit for NSG participants. Weight and height were measured, and body mass index was calculated. A single calibrated examiner performed full-mouth periodontal examinations at six sites per tooth, excluding third molars. Measures included plaque index, probing pocket depth, clinical attachment level, and bleeding on probing. Unstimulated whole saliva was collected by passive drooling between 08:00 and 10:00 after at least 2 hours without eating, drinking, smoking, toothbrushing, or mouthrinse use. Samples were centrifuged, aliquoted, stored at -80 °C, and analyzed in duplicate for salivary IL-6 and TNF-α using commercial ELISA kits. All participants received standardized oral-hygiene instructions at baseline and were advised to maintain their usual oral care. No periodontal treatment was provided during follow-up unless clinically necessary.

The primary outcomes were longitudinal changes in salivary IL-6 and TNF-α, with the principal comparison from baseline to 6 months. Secondary outcomes were longitudinal changes in plaque index, bleeding on probing, probing pocket depth, and clinical attachment level. Body weight and body mass index were contextual outcomes. Exploratory analyses examined associations between cytokine and periodontal measures. The study was designed as a pilot to assess feasibility, refine procedures, and estimate preliminary effect sizes rather than establish definitive efficacy. A formal efficacy sample-size calculation was not performed; the target sample was based on recruitment feasibility, surgical scheduling capacity, ability to complete repeated periodontal and saliva visits, and available time and funding.

Inclusion criteria

• Age 18 to 65 years.
• Body mass index (BMI) ≥35 kg/m² with one or more obesity-related comorbidities, or BMI ≥40 kg/m².
• Stage I-III periodontitis according to the 2018 periodontitis stage/grade classification.
• At least 12 natural teeth in each dental arch.
• Written informed consent provided before enrollment.

Exclusion criteria

• • Smoking more than 10 cigarettes per day.

• Periodontal treatment within the previous 6 months.
• Pregnancy or lactation.
• Previous bariatric surgery.
• Active autoimmune disorder, malignant disease, or another systemic disease known to markedly affect periodontal inflammation.
• Recent antibiotic use
• Recent systemic corticosteroid use
• Regular non-steroidal anti-inflammatory drug use within 90 days before enrollment.
• Current anti-obesity glucagon-like peptide-1 (GLP-1) therapy.