MicroRepair® ABX vs Chlorhexidine 0.12% in Gingivitis Patients (GEM-CHX012)

Clinical and Salivary aMMP-8 Evaluation of 0.12% Chlorhexidine Versus MicroRepair® ABX Mouthwash in the Non-Surgical Management of Plaque-Induced Gingivitis: A Randomized Controlled Trial

This randomized controlled clinical trial is designed to compare the adjunctive effects of two mouthwashes used after professional biofilm removal in patients with generalized plaque-induced gingivitis, a reversible inflammatory condition caused by dental plaque accumulation. The two interventions under investigation are a 0.12% chlorhexidine (CHX) mouthwash, commonly used as a reference antiseptic, and a MicroRepair® ABX mouthwash containing a multi-component antibacterial complex composed of cetylpyridinium chloride, magnolol, and honokiol, combined with biomimetic hydroxyapatite.

All participants will receive standardized professional oral hygiene treatment according to the Guided Biofilm Therapy (GBT) protocol. Following this procedure, participants will be randomly assigned to one of the two study groups and instructed to use the allocated mouthwash twice daily for 14 days as an adjunct to routine oral hygiene.

Clinical outcomes will include measures of gingival inflammation and plaque accumulation, such as Full-Mouth Bleeding Score (FMBS) and Full-Mouth Plaque Score (FMPS), along with additional periodontal parameters (probing pocket depth, clinical attachment level, and gingival recession). Treatment-related effects such as tooth staining and dentinal hypersensitivity will also be evaluated. A biological outcome will be assessed through the measurement of salivary levels of active matrix metalloproteinase-8 (aMMP-8), a biomarker associated with periodontal inflammation. Patient-reported outcomes, including perceptions of gingival condition, oral comfort, and taste acceptability, will also be collected.

Participants will be followed for 6 months. The study aims to determine whether the MicroRepair® ABX mouthwash provides clinical, biological, and patient-reported outcomes comparable to those of chlorhexidine when used as an adjunct to professional biofilm removal in the management of plaque-induced gingivitis.

Study Overview

• Status: Completed
• Conditions: Gingivitis; Dental Plaque; Gingival Inflammation
• Intervention / Treatment: Drug: MicroRepair ABX mouthwash; Drug: Chlorhexidine 0.12% mouthwash

Detailed Description

Gingivitis is the most common reversible form of periodontal disease and is primarily caused by the accumulation of bacterial biofilm along the gingival margin. Chlorhexidine digluconate is widely used as an adjunct to professional oral hygiene; however, its use may be associated with adverse effects such as tooth staining, taste alteration, and mucosal irritation. In recent years, alternative formulations combining antibacterial agents and biomimetic hydroxyapatite have been investigated for their potential role in plaque control and gingival inflammation management.

This randomized, controlled, monocentric clinical trial aims to compare the clinical and biological effects of a mouthwash containing a multi-component antibacterial complex (MicroRepair® ABX), composed of cetylpyridinium chloride, magnolol, and honokiol combined with biomimetic hydroxyapatite, with those of a 0.12% chlorhexidine (CHX) mouthwash in patients with generalized plaque-induced gingivitis. Forty adult participants will be randomly assigned to receive professional oral hygiene followed by 14 days of adjunctive use of either the MicroRepair® ABX mouthwash or the 0.12% CHX mouthwash.

The primary endpoint is the reduction in gingival bleeding, assessed by the Full-Mouth Bleeding Score (FMBS). Secondary outcomes include changes in dental plaque accumulation (Full-Mouth Plaque Score, FMPS), probing pocket depth (PPD), clinical attachment level (CAL), gingival recession (REC), salivary levels of active matrix metalloproteinase-8 (aMMP-8), tooth staining assessed by the Modified Lobene Stain Index, dentinal hypersensitivity assessed by the Schiff Air Index, and patient-reported outcomes related to oral perception and tolerability.

Participants will be followed at 2 weeks, 1 month, 3 months, and 6 months. This study is designed to evaluate whether the tested multi-component mouthwash provides clinical and biological outcomes comparable to those of chlorhexidine when used as an adjunct to professional oral hygiene in the management of plaque-induced gingivitis.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Lombardy
    • Pavia, Lombardy, Italy, 27100
      • Unit of Orthodontics and Pediatric Dentistry - Section of Dentistry - Department of Clinical, Surgical, Diagnostic and Pediatrics - University of Pavia

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adults aged between 18 and 70 years
• Presence of generalized plaque-induced gingivitis, defined by bleeding on probing (BoP) ≥30% in the absence of clinical attachment loss, with probing pocket depth ≤3 mm at ≥90% of sites
• At least 20 natural teeth
• Good general health (ASA I or II)
• Signed written informed consent
• Willingness to comply with study protocol and attend all follow-up visits

Exclusion Criteria:

• Periodontitis, defined as interdental clinical attachment loss (CAL) at ≥2 non-adjacent teeth
• Systemic conditions known to affect periodontal status, including diabetes mellitus and immunodeficiencies
• Antibiotic or anti-inflammatory therapy within the previous 3 months
• Professional dental prophylaxis within the previous 3 months
• Pregnancy or breastfeeding
• Known allergy to chlorhexidine or MicroRepair components
• Use of orthodontic appliances or removable prostheses
• Smoking more than 10 cigarettes per day
• Participation in other clinical trials within the previous 6 months

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MicroRepair® ABX Mouthwash Group; Participants assigned to the experimental group will undergo baseline clinical assessments (T0) followed by professional supragingival prophylaxis according to the Guided Biofilm Therapy (GBT) protocol. Standardized oral hygiene instructions will be provided. Participants will then use a MicroRepair® ABX mouthwash, containing cetylpyridinium chloride, magnolol, honokiol, and biomimetic hydroxyapatite, twice daily for 14 days.	Drug: MicroRepair ABX mouthwash; Participants begin at T0 (baseline) with clinical assessments, oral hygiene instruction, and the start of a 14-day home regimen using MicroRepair® ABX mouthwash. The formulation contains zinc-hydroxyapatite with antibacterial agents (cetylpyridinium chloride, magnolol, honokiol). Mouthwash is used twice daily (10 mL for 30 seconds) without rinsing, and participants avoid food or drink for 1 hour afterward. All participants use the same sodium lauryl sulfate (SLS)-free toothpaste (Biorepair®) throughout the study.; Other Names: MicroRepair® ABX
Active Comparator: 0.12% Chlorhexidine Mouthwash Group; Participants assigned to the comparator group will undergo baseline clinical assessments (T0), followed by professional supragingival prophylaxis performed according to the Guided Biofilm Therapy (GBT) protocol, including plaque disclosure, ultrasonic instrumentation (EMS Piezon), and air polishing with glycine powder. Standardized oral hygiene instructions will be provided. After this initial phase, participants will be instructed to use a 0.12% chlorhexidine (CHX) mouthwash twice daily for 14 days.	Drug: Chlorhexidine 0.12% mouthwash; Participants begin at T0 (baseline) with clinical assessments, oral hygiene instruction, and the start of a 14-day home regimen using 0.12% chlorhexidine (CHX) mouthwash. Mouthwash is used twice daily (10 mL for 30 seconds) without rinsing, and participants avoid food or drink for 1 hour afterward. All participants use the same SLS-free toothpaste (Biorepair®) throughout the study.; Other Names: Chlorhexidine 0.12%

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in gingival inflammation assessed by Full Mouth Bleeding Score (FMBS)	FMBS measures the percentage of bleeding sites after gentle probing at four sites per tooth (mesial, buccal, distal, lingual). It reflects the presence and severity of gingival inflammation. Scores range from 0% (no bleeding) to 100% (bleeding at all sites). A higher FMBS indicates more severe gingival inflammation. Comparison of FMBS over time will be used to assess clinical response to treatment.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in taste perception assessed by a validated taste alteration questionnaire	Taste perception will be evaluated using a validated patient-reported questionnaire that explores the presence and severity of taste alterations (e.g., bitter, metallic, or unpleasant taste). Each item is scored on a 5-point Likert scale: 0 = no alteration, 1 = mild alteration, 2 = moderate alteration, 3 = severe alteration, 4 = very severe alteration. The total score reflects the degree of dysgeusia perceived by the patient. Mean scores will be compared between groups at each time point to assess tolerability of the mouthwashes.	2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)
Change in plaque accumulation assessed by Full Mouth Plaque Score (FMPS)	The Full Mouth Plaque Score (FMPS) quantifies the percentage of tooth surfaces with visible dental plaque, assessed after plaque disclosure at four sites per tooth (mesial, buccal, distal, lingual). The score is calculated as the number of plaque-positive sites divided by the total number of sites ×100. Scores range from 0% (no plaque) to 100% (plaque on all surfaces). Lower scores indicate better oral hygiene. FMPS will be compared between groups across time points.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)
Change in salivary inflammation assessed by activated Matrix Metalloproteinase-8 (aMMP-8) levels	Active matrix metalloproteinase-8 (aMMP-8) is a salivary biomarker of periodontal inflammation, measured with a commercial immunoenzymatic test (aMMP-8 Test®, Biomolecular Diagnostic). Results are expressed in nanograms per milliliter (ng/mL). Reference ranges: <8 ng/mL = no inflammation; 9-19 ng/mL = mild inflammation; ≥20 ng/mL = severe inflammation. aMMP-8 levels will be compared between groups from baseline (T0) to 2 weeks (T1).	Baseline (T0), 2 weeks (T1)
Change in gingival recession assessed by Recession (REC)	Gingival Recession (REC) is defined as the distance in millimeters between the cemento-enamel junction (CEJ) and the gingival margin, measured at six sites per tooth with a calibrated periodontal probe. Scores typically range from 0 mm (no recession) to ≥5 mm (advanced recession). Higher values indicate greater apical migration of the gingival margin. REC will be compared between groups across time points.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)
Change in clinical attachment level assessed by Clinical Attachment Level (CAL)	Clinical Attachment Level (CAL) is the distance from the cemento-enamel junction (CEJ) to the bottom of the gingival sulcus or periodontal pocket, measured in millimeters at six sites per tooth with a calibrated periodontal probe (Hu-Friedy PCP UNC 15). Scores typically range from 0 mm (healthy attachment) to ≥7 mm (severe attachment loss). Higher values indicate more severe periodontal damage. CAL will be compared between groups across time points.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)
Change in periodontal probing depth assessed by Probing Pocket Depth (PPD)	Periodontal probing depth (PPD) is defined as the distance from the gingival margin to the bottom of the gingival sulcus or periodontal pocket, measured in millimeters using a calibrated periodontal probe (Hu-Friedy PCP UNC 15). PPD is assessed at six sites per tooth (mesiobuccal, midbuccal, distobuccal, mesiolingual, midlingual, distolingual). For each participant, a mean PPD value is calculated at each time point. Typical scores range from 1 mm (healthy sulcus) to ≥7 mm (advanced pocket), with higher values indicating more severe periodontal inflammation or attachment loss. The primary endpoint is the change in mean PPD from baseline (T0) to 6 months (T4), comparing the two intervention groups: MicroRepair® ABX mouthwash regimen versus 0.12% chlorhexidine (CHX) mouthwash regimen.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)
Change in extrinsic staining assessed by Modified Lobene Stain Index (MLSI)	The Modified Lobene Stain Index (MLSI) assesses extrinsic tooth staining on buccal and lingual/palatal surfaces. Each surface is scored for stain area and intensity, with total scores ranging from 0 (no stain) to 3 (severe stain). Higher scores indicate more pronounced extrinsic discoloration. Index scores will be compared between groups across time points.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)
Change in dentin hypersensitivity assessed by Schiff Air Index (SAI)	The Schiff Air Index (SAI) measures dentinal hypersensitivity in response to an air stimulus applied to the cervical area of the tooth. Scores range from 0 (no response) to 3 (painful response and request to stop). Higher scores indicate greater dentinal hypersensitivity. Scores will be compared between groups across time points.	Baseline (T0), 2 weeks (T1), 1 month (T2), 3 months (T3), 6 months (T4)

Collaborators and Investigators

• Sponsor: University of Pavia
• Investigators: Principal Investigator: Andrea Scribante, Associate Professor, University of Pavia

Study record dates

Study Major Dates

• Study Start (Actual): August 30, 2025
• Primary Completion (Actual): February 28, 2026
• Study Completion (Actual): March 10, 2026

Study Registration Dates

• First Submitted: July 19, 2025
• First Submitted That Met QC Criteria: July 19, 2025
• First Posted (Actual): July 28, 2025

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 18, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Randomized Controlled Trial; Oral Hygiene; Mouthwash; Dental Plaque; Gingivitis; aMMP-8; Guided Biofilm Therapy; Gingival Inflammation; MicroRepair ABX; Chlorhexidine 0.12%
• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Tooth Diseases; Infections; Gingival Diseases; Dental Deposits; Dental Plaque; Gingivitis; Organic Chemicals; Chemical Actions and Uses; Biomedical and Dental Materials; Manufactured Materials; Technology, Industry, and Agriculture; Specialty Uses of Chemicals; Biguanides; Guanidines; Amidines; Cosmetics; Chlorhexidine; Mouthwashes
• Other Study ID Numbers: 2025-CHX0.12vsABX

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Data will be available upon motivated request to the corresponding authors.

Drug and device information, study documents

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