This randomized, single-blind clinical trial aims to evaluate the short-term effectiveness of two different oral hygiene instruction (OHI) methods-video-assisted instruction versus traditional 3D model demonstration-on periodontal clinical parameters in patients diagnosed with gingivitis. A critical secondary objective of this study is to investigate the predictive role of patients' baseline Oral Hygiene-Related Self-Efficacy (OHSE) on the extent of clinical healing, and to assess changes in patient-reported subjective gingival health using a Visual Analogue Scale (VAS). A total of 80 patients undergoing standard Phase 1 periodontal therapy (scaling and root planing) are randomly assigned in a 1:1 ratio to either the video instruction group or the model instruction group. Periodontal clinical indices, including Plaque Index (PI), Gingival Index (GI), Probing Depth (PD), and Bleeding on Probing (BOP), alongside patient-reported outcomes, are recorded at baseline and at a one-month follow-up by a blinded examiner. The primary hypothesis is that video-based instruction is non-inferior to conventional model-based instruction in improving clinical parameters. Furthermore, the study hypothesizes that a patient's baseline self-efficacy level-independent of the educational method received-significantly predicts the reduction in periodontal inflammation and bleeding scores.

Background and Rationale Gingivitis is a reversible inflammatory condition of the gingival tissues caused by the accumulation of dental plaque. The gold standard for its prevention and treatment is professional mechanical plaque removal (Phase 1 periodontal therapy) combined with effective, daily supragingival plaque control by the patient. However, maintaining long-term patient compliance and motivation remains a significant clinical challenge. Traditionally, oral hygiene instruction (OHI) involves verbal guidance and practical demonstration of brushing and interdental cleaning techniques on 3D dental models. With the integration of digital health technologies, video-based educational tools have emerged as a viable alternative. Video instructions offer standardized content and optimize the clinician's chair-time, which is highly valuable in busy clinical settings. While clinical indices objectively measure disease severity, contemporary periodontal care increasingly recognizes the crucial role of psychological and behavioral factors in treatment success. Oral hygiene-related self-efficacy (OHSE)-a patient's belief in their ability to maintain oral care habits even under taxing situations-is a key cognitive determinant of behavior change. Therefore, evaluating clinical outcomes in conjunction with OHSE and Patient-Reported Outcome Measures (PROMs) provides a more comprehensive understanding of periodontal healing dynamics. Study Objectives The primary objective of this study is to compare the short-term clinical efficacy of video-based versus model-based OHI delivered as an adjunct to Phase 1 periodontal treatment in patients with gingivitis. The secondary objective is to evaluate whether patients' baseline OHSE scores predict the amount of clinical improvement (reductions in Plaque Index and Bleeding on Probing) and to assess changes in self-reported gingival symptoms using a Visual Analogue Scale (VAS). Methodology and Study Design This study is designed as a prospective, randomized, single-blind, parallel-group clinical trial conducted at Ankara University Faculty of Dentistry. The trial enrolls 80 eligible patients diagnosed with plaque-induced gingivitis, characterized by a whole-mouth average Gingival Index (GI) > 2.0 and no probing depths > 4 mm. Patients with a history of systemic diseases affecting periodontal tissues, current smokers, and those who received antibiotic therapy within the last 3 months are excluded. Clinical and Behavioral Assessments Prior to any intervention (Baseline - T0), a blinded examiner assesses the periodontal health of the participants using the Plaque Index (PI), Gingival Index (GI), Probing Depth (PD), and Bleeding on Probing (BOP) at six sites per tooth. Following the clinical examination, patients complete a validated Oral Hygiene-Related Self-Efficacy (OHSE) questionnaire, which evaluates their confidence in performing toothbrushing, interdental cleaning, and regular dental visits under various psychological barriers. Additionally, patients rate their subjective gingival symptoms (e.g., bleeding, swelling, bad breath) using a 10-point VAS. Intervention Following baseline assessments, all patients receive standard Phase 1 periodontal treatment, consisting of full-mouth supragingival and subgingival scaling and polishing using ultrasonic instruments and hand curettes. Immediately after the mechanical therapy, patients are randomly allocated to one of two groups (1:1 ratio): Video Group: Patients receive a digital link to a standardized instructional video demonstrating proper toothbrushing and interdental cleaning techniques. Model Group: Patients receive one-on-one practical oral hygiene instruction demonstrated by a clinician on a 3D dental model. Follow-up and Statistical Analysis Patients are recalled at 1 month (T1) post-intervention. The same blinded examiner repeats all clinical measurements (PI, GI, PD, BOP) and patients re-evaluate their subjective gingival symptoms (VAS). Statistical analyses will be performed to assess within-group and between-group variations. The comparison of clinical improvement amounts (Δ T0 - T1) between the Video and Model groups will be conducted using Independent Samples t-tests and Analysis of Covariance (ANCOVA), adjusting for baseline clinical values and initial OHSE scores. Correlation analyses will be employed to examine the predictive relationship between baseline OHSE subsets (particularly interdental cleaning self-efficacy) and objective reductions in periodontal inflammation.

Inclusion Criteria:

Patients officially diagnosed with plaque-induced gingivitis. Patients having an average whole-mouth Gingival Index (GI) score strictly above 2.0 at baseline.

Patients aged between 18 and 65 years. Patients who have provided written informed consent to participate in the study.

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Exclusion Criteria:

Individuals with an average whole-mouth Gingival Index (GI) score of 2.0 or below.

Individuals presenting with periodontal pockets deeper than 4 mm in any single area of the mouth.

Individuals who possess fixed prosthetic restorations on any tooth. Individuals who have received any form of professional periodontal treatment within the last 6 months.

Individuals who currently smoke or use similar tobacco products. Individuals who have used systemic antibiotics for any medical or dental reason within the last 3 months.

Individuals who are physically or cognitively unable to perform adequate daily oral hygiene practices.

Individuals who have lost 5 or more natural teeth (excluding third molars/wisdom teeth).

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All collected de-identified individual participant data (IPD) that underlie the results reported in the final published article will be shared. This includes demographic data, clinical periodontal indices (PI, GI, PD, BOP), and patient-reported outcome measures (OHSE and VAS scores).

Data will be available beginning 6 months and ending 36 months following the publication of the article.

Data will be shared with researchers who provide a methodologically sound proposal for the purpose of achieving the specific aims outlined in their approved proposal. Requests should be directed to the corresponding author via email.

Due to the educational and interactive nature of the interventions (watching a video vs. receiving hands-on model demonstration), it is not possible to blind the patients or the care provider (the clinician delivering the instruction). Therefore, masking is strictly limited to the Outcomes Assessor (the clinical examiner), who performs all baseline (T0) and follow-up (T1) periodontal measurements and remains completely unaware of the patients' group allocation throughout the study.