Comparing the Efficacy of Toothbrushing With and Without Interproximal Cleaning Aids: A Split-Mouth Trial

This prospective split-mouth clinical trial aims to evaluate the effectiveness and safety of different interproximal cleaning aids used in addition to toothbrushing compared with toothbrushing alone in dental students diagnosed with gingivitis and presenting with intact interdental papillae.

The study will investigate whether toothbrushing alone, when performed using a standardized and effective technique, is sufficient for maintaining plaque control and gingival health, or whether the addition of interproximal cleaning devices provides further clinical benefits. The study will also assess the potential impact of these devices on interdental papilla integrity, possible soft tissue trauma, and participant motivation and adherence.

Participants will be dental students enrolled at Saint Joseph University of Beirut who meet the eligibility criteria. Eligible participants will present with gingivitis, intact interdental papillae, and no periodontal attachment loss or conditions that may interfere with periodontal health assessment. Participants with orthodontic appliances, crowns, implants, dentures, periodontitis, diastemas, systemic conditions affecting periodontal health, or medications causing gingival enlargement will be excluded.

Each participant's mouth will be divided into four quadrants in a split-mouth design. A computer-generated randomization sequence will determine the starting position of the assigned interventions to minimize site-related bias. Each quadrant will receive one of the following oral hygiene protocols:

• Quadrant 1: Toothbrushing alone (control).
• Quadrant 2: Toothbrushing combined with an interproximal brush (IPB).
• Quadrant 3: Toothbrushing combined with a water flosser (WF).
• Quadrant 4: Toothbrushing combined with a rubber toothpick (RT).

All participants will receive standardized oral hygiene instructions and a dental kit containing a soft toothbrush, fluoride toothpaste, interproximal brush, water flosser, and rubber toothpick. Participants will perform the modified Bass toothbrushing technique twice daily, in the morning and after the last meal of the day, for a period of one month (4 weeks).

For the interproximal brush group, participants will perform gentle back-and-forth movements five times in each interdental space. For the water flosser group, participants will direct the irrigator tip along the gingival margin and interdental papillae using continuous flow mode while avoiding direct contact with gingival tissues. For the rubber toothpick group, participants will perform gentle back-and-forth movements five times in each interdental space.

Clinical evaluations will be performed at four time points:

• T0: baseline before the use of interproximal cleaning aids.
• T7: one week after intervention initiation.
• T14: two weeks after intervention initiation.
• T30: one month after intervention initiation.

The primary outcomes will include:

• Quadrant Plaque Score (QPS) to evaluate plaque accumulation.
• Quadrant Bleeding Score (QBS) to assess gingival inflammation.

Secondary outcomes will include:

• Interdental papilla assessment using the Papilla Presence Index (PPI) to evaluate papillary changes and potential soft tissue damage.
• Participant motivation and satisfaction scores based on a 1-10 subjective scale evaluating ease of use, comfort, and adherence to each cleaning method.

All clinical measurements will be performed by the same calibrated examiner using a Hu-Friedy PCPUNC 15 periodontal probe. The study will provide comparative data regarding the effectiveness, safety, and acceptability of commonly used interproximal cleaning devices in individuals with gingivitis and good oral hygiene skills.