Touch-to-Teach Interdental Brush Instruction Versus Conventional Guidance on Gingival Health in Patients With Fixed Dental Prostheses

June 7, 2026 updated by: Gulf Medical University

Assessing the Impact of Interdental Brushing on Gingival Health and Patient-Reported Outcome Measures in Individuals With Fixed Prostheses: A Single-Blind Randomized Controlled Clinical Trial

Why is this study being done? People with dental crowns often develop inflamed gums because bacteria accumulate in the tight spaces between teeth that a regular toothbrush cannot reach. Interdental brushes can clean these spaces, but patients frequently use them incorrectly. This study tested whether a personalised, hands-on instructional method called Touch-to-Teach produces healthier gums compared with standard dental hygiene advice.

Who participated? 40 adults with at least one porcelain-fused-to-metal crown in the molar region with supragingival margins took part at Thumbay University Hospital, Ajman, UAE. Four participants withdrew; 36 completed the three-month study.

What did participants do? All participants received full-mouth scaling and standardised toothbrushing instruction. Group 1 (Touch-to-Teach) additionally received probe-guided, site-specific interdental brush selection and guided in-mouth training, with correctly sized brushes provided for home use. Group 2 (Conventional Instruction) received verbal advice, educational videos, and a model-based demonstration, with brush size selected empirically and no brushes provided for home use. Follow-up visits were conducted at one, two, and three months.

What was measured? A blinded examiner recorded gum inflammation, plaque levels, gum pocket depth, and bleeding at each visit. Both groups completed a questionnaire on brush comfort, perceived efficacy, and satisfaction at one and three months.

What were the key results? The Touch-to-Teach group showed significantly greater reductions in plaque accumulation, gingival inflammation, and probing depth compared with the control group. Both groups showed meaningful reductions in gingival bleeding over time, with no statistically significant difference between groups at three months. Patient-reported outcomes consistently favoured the Touch-to-Teach group. These findings suggest that calibrated, personalised interdental brush instruction may offer advantages for patients with fixed dental prostheses.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Background Patients with fixed dental prostheses are at increased risk of interproximal plaque accumulation due to altered crown contour and interdental geometry. Although interdental brushes are the most effective adjunct to toothbrushing for interproximal plaque removal, no randomised trial had previously evaluated the impact of instructional method on gingival outcomes in this patient population. The Touch-to-Teach method combines chairside probe-guided brush size calibration with hands-on guided in-mouth training, offering a more individualised approach than conventional model-based instruction.

Study Design Single-blind, parallel-group randomised controlled trial conducted at Thumbay University Hospital, Ajman, UAE. Ethics approval: IRB-COD-STD-69-FEB-2024. Written informed consent obtained from all participants prior to enrolment.

Interventions All participants received standardised full-mouth debridement and toothbrushing instruction before baseline. The test group received probe-guided, site-specific interdental brush selection using the Curaprox CPS Colorimetric Probe System, followed by guided in-mouth training until proficiency was demonstrated; size-calibrated brushes were provided for home use. The control group received empirical brush size selection, verbal instruction, access to EFP patient portal educational videos, and model-based demonstration; no brushes were provided for home use.

Outcomes Primary outcome: change in Gingival Index from baseline to three months. Secondary outcomes: Plaque Index, Bleeding on Probing, Probing Depth, and patient-reported outcome measures, assessed at baseline, one, two, and three months by a blinded examiner.

Sample Size Minimum 32 participants required (α = 0.05, power = 80%). Inflated by 25% to 40 participants to account for attrition. Sixty patients screened; 40 enrolled; 36 completed the three-month follow-up (18 per group; 4 withdrew).

Statistical Analysis Continuous outcomes analysed using independent t-tests or Mann-Whitney U test depending on normality. Categorical variables compared using Fisher's exact test. Intragroup BOP changes assessed using Cochran's Q test. Multiple comparisons corrected using Holm's sequential method. Significance set at p < 0.05. Analyses performed in R version 4.3.2.You've used 75% of your weekly limitGet more usageSonnet 4.6Adaptive

Study Type

Interventional

Enrollment (Actual)

32

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Arab Emirates
    • Ajman Emirate
      • Ajman, Ajman Emirate, United Arab Emirates
        • ostgraduate Dental Center, Thumbay University Hospital, Gulf Medical University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults aged 18 years and older
  • Presence of at least one porcelain-fused-to-metal (PFM) crown in the molar region with supragingival margins, in occlusal function for a minimum of 3 months prior to enrollment
  • Prosthesis does not interfere with the supracrestal attachment apparatus (biologic width preserved)
  • Clinically healthy periodontium confirmed at screening, with no signs of periodontal disease as per the 2017 World Workshop classification criteria
  • Systemically healthy with no conditions known to affect periodontal healing or gingival response
  • Ability and willingness to attend all scheduled study visits at baseline, 1 month, 2 months, and 3 months

  • Willing and able to provide written informed consent

    -- Exclusion Criteria:

  • Uncontrolled diabetes mellitus
  • Use of interdental brushes within the previous 6 months
  • Current smoker or any tobacco user
  • Use of systemic antibiotics or anti-inflammatory medications within the previous 3 months
  • Regular use of anti-plaque or antimicrobial mouth rinses within the previous 3 months
  • Currently pregnant or breastfeeding
  • Fractured or defective fixed prosthesis requiring repair or replacement prior to enrollment
  • Inability to attend scheduled follow-up visits

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Touch-to-Teach Instruction
Participants received standardized oral hygiene instruction (Modified Bass technique) and full-mouth scaling and root surface debridement, plus individualized Touch-to-Teach interdental brush instruction using the Curaprox Chairside System. A color-coded CPS colorimetric probe measured each interproximal space precisely (blue 0.6mm, red 0.7mm, pink 0.8mm, yellow 0.9mm, green 1.1mm). Matching color-coded brushes were prescribed per site. The clinician demonstrated correct technique on a dental model then guided each patient through the procedure in their own mouth until correct insertion, manipulation, and removal were demonstrated at each designated space. Prescribed size-calibrated interdental brushes were provided for home use throughout the 3-month study period
Behavioral: Touch-to-Teach interdental brush instruction

Individualized interdental brush care delivered using the Curaprox Chairside System (Curaprox AG) through three structured phases:

Diagnostic Phase: CPS colorimetric probe with five autoclavable color-coded tips (blue 0.6mm, red 0.7mm, pink 0.8mm, yellow 0.9mm, green 1.1mm) used to measure precise accessibility diameter of each interproximal space.

Prescription Phase: Matching color-coded interdental brush selected per space. Brush correctly sized when fitting snugly without wire bending or forceful insertion required.

Training Phase: Clinician demonstrated technique on dental model then guided patient through procedure in their own mouth until proficiency in correct insertion angle, gentle manipulation, and removal was achieved at each space. Prescribed brushes provided for daily home use for 3 months.
Active Comparator: Conventional Instruction (Active Comparator)
Participants received standardized oral hygiene instruction (Modified Bass technique) and full-mouth scaling and root surface debridement. Conventional guidance comprised verbal instruction, access to European Federation of Periodontology animated patient education videos on interdental cleaning, and chairside hands-on demonstration of interdental brush insertion and manipulation using dental models with error correction. Brush size was selected empirically by the clinician without a calibrated sizing system. No personalized brush prescription, no CPS probe measurement, and no in-mouth guided insertion were provided.
Behavioral: Conventional oral hygiene instruction
Standardized oral hygiene guidance comprising: verbal instruction in Modified Bass toothbrushing technique; access to European Federation of Periodontology patient portal animated education videos demonstrating interdental cleaning techniques; and chairside hands-on demonstration of interdental brush insertion and manipulation using dental models with corrections provided as necessary. Brush size selected empirically without calibrated probe system. No personalized brush prescription, no CPS probe measurement, and no in-mouth guided insertion performed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Gingival Index (GI)
Time Frame: Baseline, 1, 2, and 3 months (primary endpoint: 3 months)
Description: Full-mouth Gingival Index (Löe & Silness, 1963) assessed at crown-adjacent interproximal sites on a 0-3 ordinal scale: 0 = normal gingiva; 1 = mild inflammation, no bleeding on probing; 2 = moderate inflammation with bleeding on probing; 3 = severe inflammation with spontaneous bleeding tendency.
Baseline, 1, 2, and 3 months (primary endpoint: 3 months)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bleeding on Probing (BOP%)
Time Frame: Baseline, 1 month, 2 months, and 3 months
Presence or absence of bleeding within 10 seconds of gentle probing of the sulcus or pocket recorded at 6 sites per tooth using a UNC-15 periodontal probe. Expressed as percentage of bleeding-positive sites out of total sites examined. Clinical indicator of gingival inflammation and tissue response to each instructional method. Assessed by blinded examiner
Baseline, 1 month, 2 months, and 3 months
Patient-reported acceptability (PROM)
Time Frame: 3 months
Five-item questionnaire assessing: acceptability of interdental brush use, discomfort during use, willingness to recommend interdental brushes to others, perceived plaque removal efficacy, and self-reported regularity of use. Each item scored on a five-point Likert scale (1 = most negative response to 5 = most positive response); total scores range from 5 to 25, with higher scores indicating greater acceptability of the Touch-to-Teach instructional method. Reported as exploratory.
3 months
Plaque Index (PI)
Time Frame: Baseline, 1 month, 2 months, and 3 months
Full-mouth plaque assessed using O'Leary Plaque Control Record at 6 sites per tooth (mesiobuccal, midbuccal, distobuccal, mesiolingual, midlingual, distolingual) by running a UNC-15 periodontal probe along the gingival margin. Presence of plaque scored as 1, absence as 0. Reflects degree of interproximal plaque control achieved by each instructional method. Assessed by blinded examiner.
Baseline, 1 month, 2 months, and 3 months
Probing Pocket Depth (PD)
Time Frame: Baseline, 1 month, 2 months, and 3 months
Plaque accumulation recorded at crown-adjacent sites using the Plaque Index of Silness and Löe, applied without a disclosing agent, on a 0-3 ordinal scale: 0 = no plaque detectable by visual inspection or probe; 1 = no plaque visible to the naked eye but detectable by running the probe tip along the gingival margin; 2 = a moderate layer of plaque visible at the gingival margin; 3 = abundant soft deposits filling the gingival crevice. Higher scores indicate greater plaque accumulation. Assessed by a blinded examiner.
Baseline, 1 month, 2 months, and 3 months
Patient-Reported Outcome Measures (PROMs)
Time Frame: 1 month and 3 months
Two-part structured questionnaire. At baseline, a three-item screen assessed prior awareness of interdental cleaning aids and current oral hygiene practices. At one and three months, acceptability was assessed across four domains: comfort during interdental brush use, ease of use, perceived oral cleanliness, and overall satisfaction. Each item scored on a five-point Likert scale (1 = most negative to 5 = most positive); total scores range from 4 to 20, with higher scores indicating greater patient acceptability of the Touch-to-Teach instructional method. Reported as exploratory. Assessed by a blinded examiner.
1 month and 3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Gulf Medical University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 15, 2024

Primary Completion (Actual)

June 15, 2025

Study Completion (Actual)

June 15, 2025

Study Registration Dates

First Submitted

May 20, 2026

First Submitted That Met QC Criteria

June 7, 2026

First Posted (Actual)

June 9, 2026

Study Record Updates

Last Update Posted (Actual)

June 9, 2026

Last Update Submitted That Met QC Criteria

June 7, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MDSPerio2023 - 1

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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