This randomized clinical trial aims to evaluate and compare the effectiveness of surgical and nonsurgical treatment approaches for the management of interdental black triangles. Black triangles are open gingival embrasures caused by the loss or deficiency of the interdental papilla between adjacent teeth. These spaces are a common esthetic concern and may also contribute to food impaction and periodontal problems.

Thirty adult patients presenting with interdental papillary loss classified as Nordland and Tarnow Class I or II will be recruited from the outpatient clinics of the Faculty of Dentistry at King Salman International University. Eligible participants will be randomly assigned to one of three treatment groups: surgical reconstruction using the tube grafting technique, papillary augmentation using hyaluronic acid injection, or a restorative approach using the injection molding composite technique.

Clinical and photographic assessments will be performed at baseline and during follow-up visits at 3 and 6 months after treatment. The primary outcomes will be the reduction in black triangle surface area and height. Secondary outcomes will include clinical periodontal parameters such as plaque index, bleeding score, probing pocket depth, and clinical attachment level. Patient satisfaction with the esthetic outcome will also be evaluated using a Visual Analog Scale (VAS).

The findings of this study are expected to provide evidence regarding the comparative effectiveness of surgical and nonsurgical approaches for the management of interdental black triangles and help clinicians select the most predictable treatment modality for improving esthetic outcomes.

Interdental papilla deficiency resulting in the formation of "black triangles" is a frequent esthetic and functional problem in dentistry. These open gingival embrasures occur due to several factors including periodontal attachment loss, traumatic oral hygiene practices, tooth morphology, orthodontic treatment, and aging. In addition to compromising dental esthetics, black triangles may lead to food impaction, phonetic problems, and patient dissatisfaction with their smile.

Several therapeutic approaches have been proposed for the management of interdental papillary loss. These approaches can generally be classified into surgical and nonsurgical techniques. Surgical methods aim to reconstruct the lost papillary tissue through soft tissue grafting procedures such as the tube grafting technique. These procedures attempt to biologically restore the interdental papilla but may involve surgical morbidity and require advanced clinical skills.

Nonsurgical approaches have recently gained interest as minimally invasive alternatives. One such approach involves the use of injectable fillers such as hyaluronic acid to augment the volume of the interdental papilla. Hyaluronic acid is widely used in aesthetic medicine due to its biocompatibility and ability to promote tissue hydration and volumization. Another nonsurgical strategy is the restorative modification of tooth contours using the injection molding composite technique, which alters the shape of the proximal tooth surfaces to reduce the appearance of the gingival embrasure.

Despite the availability of these different treatment options, there is limited evidence directly comparing surgical and nonsurgical approaches for the management of interdental black triangles. Therefore, the present study aims to evaluate the efficacy of these treatment modalities in a randomized clinical trial design.

Thirty patients presenting with interdental papilla deficiency will be recruited from the outpatient clinic of the Faculty of Dentistry at King Salman International University. Eligible participants will be adults aged 18 to 50 years with Nordland and Tarnow Class I or II papillary loss and adequate interdental bone support (≤5 mm distance from the contact point to the alveolar crest). Participants with systemic diseases affecting wound healing, active periodontal disease, periapical pathology, pregnancy or lactation, parafunctional habits, or smoking history will be excluded.

After baseline assessment, participants will be randomly allocated into three equal groups:

Group I: Surgical reconstruction of the interdental papilla using the tube grafting technique.

Group II: Papillary augmentation using hyaluronic acid injection.

Group III: Restorative treatment using the injection molding composite technique.

Baseline clinical examination will include plaque index, bleeding index, probing pocket depth, and clinical attachment level. Standardized intraoral photographs will be obtained using a digital camera under controlled conditions. Image analysis software will be used to measure the surface area and height of the black triangle.

Follow-up assessments will be conducted at 3 months and 6 months after treatment. At each follow-up visit, clinical periodontal parameters and photographic measurements will be repeated. Patient satisfaction with the esthetic outcome will be evaluated using a Visual Analog Scale.

The primary outcomes of this study are the changes in black triangle surface area and height over time. Secondary outcomes include periodontal clinical parameters and patient-reported esthetic satisfaction. The results of this randomized clinical trial are expected to provide clinically relevant evidence regarding the effectiveness and stability of surgical and nonsurgical techniques for the management of interdental black triangles, contributing to evidence-based decision-making in esthetic dental practice.

Inclusion Criteria:

• Adults aged 18 to 50 years.

Presence of interdental black triangle classified as Nordland and Tarnow Class I or Class II.

Radiographic evidence of adequate interdental bone support, defined as ≤5 mm distance from the contact point to the alveolar crest.

Systemically healthy individuals with no medical conditions affecting wound healing.

Patients willing to participate in the study and attend follow-up visits at 3 and 6 months.

Exclusion Criteria:

• Patients with systemic diseases that may impair wound healing.

Presence of teeth with acute periapical pathology.

Presence of periodontal pockets or active periodontal disease.

Pregnant or lactating women.

Patients with parafunctional habits (e.g., bruxism).

Smokers, alcoholics, or drug abusers.

Outcome assessment will be performed by an independent examiner who is blinded to the treatment allocation. The examiner responsible for measuring the black triangle dimensions and recording clinical parameters will not be involved in delivering the interventions and will remain unaware of which treatment each participant received. Standardized intraoral photographs will be coded and analyzed without identifiers indicating the assigned treatment group to maintain assessor blinding.