MICRO-SURG: Subgingival Microbiome in Peri-Implantitis, Regenerative, and Resective Periodontal Surgery (MICROSURG)

MICRO-SURG: Investigation of Subgingival Microbiome Changes Following Surgical Peri-Implantitis Therapy, Regenerative Periodontal Surgery, and Resective Periodontal Surgery Using Next-Generation Sequencing

This clinical study investigates how the subgingival microbiome changes after three different periodontal and peri-implant surgical procedures: (1) resective periodontal surgery, (2) regenerative periodontal surgery, and (3) peri-implantitis surgery. The aim is to characterize microbial shifts associated with these commonly used surgical treatments and to determine whether the type of surgery influences the recovery or disruption of the subgingival ecosystem. Adult patients with periodontitis or peri-implantitis will receive the procedure indicated for their condition. Subgingival plaque samples will be collected at baseline and at defined postoperative follow-up intervals. Microbiome analysis will be performed using next-generation sequencing (NGS), and microbial changes will be evaluated with the Subgingival Microbial Dysbiosis Index (SMDI). Insights from this study may help improve prevention, diagnostics, and treatment strategies for periodontal and peri-implant diseases.

Study Overview

• Status: Recruiting
• Conditions: Periodontitis; Periimplantitis
• Intervention / Treatment: Procedure: Resective Periodontal Surgery; Procedure: Regenerative Periodontal Surgery; Procedure: Surgical Peri-implantitis Therapy

• Study Type: Interventional
• Enrollment (Estimated): 84
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Benjamin Ehmke, Univ. -Prof. Dr. med. dent.; Phone Number: +4902518347059; Email: ehmke@uni-muenster.de
• Study Contact Backup: Name: Daniel Hagenfeld, PD Dr. med. dent.; Phone Number: +492518345092; Email: Daniel.hagenfeld@ukmuenster.de

Study Locations

• Germany
  • North Rhine-Westphalia
    • Münster, North Rhine-Westphalia, Germany, 48149
      • Recruiting
      • University Hospital Münster
      • Contact: Benjamin Ehmke, Univ.-Prof. Dr. med. dent.; Phone Number: +4902518347059; Email: ehmke@uni-muenster.de
      • Contact: Maher Heno; Phone Number: +492518345092; Email: Maher.heno@ukmuenster.de

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18 years or older
• Confirmed diagnosis of Peri-implantitis (for the peri-implantitis surgery arm), or Stage III/IV periodontitis (for the periodontal surgery arms)
• Indication for surgical therapy corresponding to the assigned study arm
• Ability to understand the study procedures and provide written informed consent
• Adequate oral hygiene (API/SBI according to the clinician's judgment)
• Willingness and ability to attend all follow-up visits
• Willingness to provide salivary and subgingival plaque samples for microbiome analyses (NGS, SMDI)

Exclusion Criteria:

• Systemic conditions contraindicating oral surgical procedures
• Severe systemic diseases (e.g., uncontrolled diabetes mellitus, immunosuppressive disorders)
• Use of systemic antibiotics within the previous 3 months
• Active COVID-19 infection at the time of surgery
• Pregnancy or breastfeeding
• Drug or alcohol abuse
• Smoking more than 10 cigarettes per day
• Known allergies to materials used in the assigned intervention (e.g., local anesthetics, sutures, membranes, bone grafting materials)
• Participation in another clinical study within the previous 30 days
• Acute oral infections that contraindicate participation
• Inability or unwillingness to comply with all follow-up appointments Lack of capacity to provide informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Resective Periodontal Surgery; Participants in this arm undergo subgingival microbiome sampling in the context of resective periodontal surgery. Microbiome samples are collected at standardized time points (preoperative baseline, intraoperative sampling, and postoperative follow-ups). Samples are analyzed using next-generation sequencing (NGS), including 16S rRNA profiling, and Structure-Microbial Diversity Index (SMDI) evaluation. The goal is to characterize microbial shifts associated with resective periodontal therapy.	Procedure: Resective Periodontal Surgery; Apically repositioned full-thickness mucoperiosteal flap with resective surgical treatment of periodontal defects. Includes removal of inflamed tissue and recontouring of osseous structures according to clinical indication. Microbiome samples are taken pre-, intra- and postoperatively.
Experimental: Regenerative Periodontal Surgery; Participants undergoing regenerative periodontal therapy are enrolled for longitudinal subgingival microbiome analysis. Microbiome samples are obtained at predefined time points (baseline, intraoperative, postoperative). Sequencing is performed using next-generation sequencing (NGS) and 16S rRNA analysis, with SMDI calculations to assess microbial diversity changes associated with regenerative procedures.	Procedure: Regenerative Periodontal Surgery; Regenerative periodontal therapy including the use of autogenous bone, membranes, and/or bone substitute materials for periodontal regeneration.
Experimental: Peri-Implantitis Surgery; Participants in this arm receive systematic peri-implant microbiome profiling before, during, and after peri-implantitis surgery. Sampling includes submucosal/peri-implant biofilm collection at standardized visits. Analyses include next-generation sequencing (NGS), 16S rRNA sequencing, and SMDI-based microbial diversity assessment to evaluate microbial changes associated with peri-implantitis therapy.	Procedure: Surgical Peri-implantitis Therapy; Surgical intervention for peri-implantitis including surgical access flap, defect debridement, implant surface decontamination, and resective or regenerative procedures as clinically indicated.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Subgingival Microbiome Composition After Periodontal and Peri-implant Surgery	Assessment of changes in the subgingival and peri-implant microbiome before, during, and after surgical treatment. Microbiome samples are collected at standardized time points and analyzed using next-generation sequencing (NGS), including 16S rRNA gene sequencing and Structure Microbial Diversity Index (SMDI). The primary outcome reflects quantitative and qualitative microbial shifts induced by resective periodontal surgery, regenerative periodontal surgery, or peri-implantitis surgery.	Baseline (preoperative), intraoperative sampling (Day 0), 1 week, 4 weeks, and 12 weeks postoperatively

Secondary Outcome Measures

Outcome Measure	Time Frame
Bleeding on probing	Baseline (preoperative) and 12 weeks postoperatively
Clinical attachment level (CAL) change	Baseline and 12 weeks postoperatively
Probing depth (PD) change	Baseline (preoperative) and 12 weeks postoperatively
Implant pocket change	Baseline (preoperative) and 12 weeks postoperatively

Collaborators and Investigators

• Sponsor: University Hospital Muenster
• Collaborators: dfg
• Investigators: Principal Investigator: Benjamin Ehmke, Univ. Prof. Dr. med. dent., Clinic for Periodontology and Conservative Dentistry, University of Münster

Publications and helpful links

General Publications

• Chen T, Marsh PD, Al-Hebshi NN. SMDI: An Index for Measuring Subgingival Microbial Dysbiosis. J Dent Res. 2022 Mar;101(3):331-338. doi: 10.1177/00220345211035775. Epub 2021 Aug 25.
• Garcia ME, Bindman AB, Coffman J. Language-Concordant Primary Care Physicians for a Diverse Population: The View from California. Health Equity. 2019 Jul 1;3(1):343-349. doi: 10.1089/heq.2019.0035. eCollection 2019.
• Aas JA, Paster BJ, Stokes LN, Olsen I, Dewhirst FE. Defining the normal bacterial flora of the oral cavity. J Clin Microbiol. 2005 Nov;43(11):5721-32. doi: 10.1128/JCM.43.11.5721-5732.2005.

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start (Actual): February 23, 2026
• Primary Completion (Estimated): May 18, 2026
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: February 9, 2026
• First Submitted That Met QC Criteria: February 9, 2026
• First Posted (Actual): February 17, 2026

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Next-Generation Sequencing; Periodontal Surgery; Microbiome Analysis; 16S rRNA Sequencing; Subgingival Microbiome; Regenerative Surgery; Resective Surgery; Peri-Implantitis Surgery; SMDI
• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Periodontitis; Peri-Implantitis
• Other Study ID Numbers: MICRO-SURG-UKM-2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No