Impact of Root Surface Conditioning With Erythritol Air Polishing and Hand Instrumentation on Recession Coverage Using the Modified Tunnel Technique and Subepithelial Connective Tissue Graft.

Mean root coverage (MRC), expressed as a percentage (%), assessed at 6 and 12 months post-surgery.

MRC is calculated as (GR₀ - GR₆) / GR₀ × 100% and (GR₀ - GR₁₂) / GR₀ × 100%, respectively.

Gingival recession (GR), measured in millimeters (mm) as the distance from the cemento-enamel junction (CEJ) to the gingival margin at the mid-buccal aspect of the tooth, is used solely as an input parameter for the calculation of MRC.

Distance from the cemento-enamel junction (CEJ) to the gingival margin measured at the mid-buccal aspect of the tooth.

Horizontal distance measured at the level of the cemento-enamel junction (CEJ) between the mesial and distal margins of the gingival recession.

Distance from the cemento-enamel junction (CEJ) to the bottom of the gingival sulcus.

Distance from the gingival margin to the bottom of the gingival sulcus.

Thickness of the gingiva measured 3 mm apical to the gingival margin at the mid-buccal aspect of the tooth.

Distance from the gingival margin to the mucogingival junction

% CRC = (number of teeth with CRC = 1 after treatment / total number of teeth with gingival recession at baseline) × 100.

CRC = 1: postoperative GR ≤ 0 mm, indicating complete root coverage. CRC = 0: postoperative GR > 0 mm, indicating partial or no root coverage.

Reduction in recession height at 6 months: GR₀ - GR₆ Reduction in recession height at 12 months: GR₀ - GR₁₂

Clinical attachment level gain at 6 months = CAL₀ - CAL₆

Clinical attachment level gain at 12 months = CAL₀ - CAL₁₂

Increase in keratinized tissue width at 6 months: KTW₆ - KTW₀ Increase in keratinized tissue width at 12 months: KTW₁₂ - KTW₀

Clinician-assessed tooth sensitivity evaluated using the Schiff Cold Air Sensitivity Scale.

Air will be delivered using a standard air syringe of the dental unit, positioned approximately 1 cm from the tooth surface for 5 seconds, at a working temperature of 23 °C (±4 °C), and directed at the exposed buccal surface of the tooth with gingival recession.

Patient response to the air stimulus will be assessed by the clinician using the Schiff Cold Air Sensitivity Scale as follows:

0 = No response to the air stimulus

• = Response to the air stimulus, but no request to discontinue the stimulus
• = Response to the air stimulus, with a request to discontinue the stimulus and/or turning away from the stimulus
• = Painful response to the air stimulus, with a request to discontinue the stimulus

Root Esthetic Score (RES), expressed as a composite score ranging from 0 to 10 points.

The RES is a clinician-assessed composite esthetic outcome comprising the following five components:

• Gingival Margin (GM): failure of root coverage (0 points), partial root coverage (3 points), complete root coverage (6 points);
• Marginal Tissue Contour (MTC): irregular gingival margin not following the cemento-enamel junction (CEJ) (0 points), scalloped gingival contour following the CEJ (1 point);
• Soft Tissue Texture (STT): presence of scar (0 points), absence of scars (1 point);
• Mucogingival Junction (MGJ): MGJ not aligned with the MGJ of adjacent teeth (0 points), MGJ aligned with the MGJ of adjacent teeth (1 point);
• Gingival Color (GC): color mismatch with adjacent teeth (0 points), color matching adjacent teeth (1 point).

The total RES score is calculated as the sum of all component scores, with higher scores indicating a better esthetic outcome.

Patient-reported discomfort during the procedure assessed using the Visual Analogue Scale (VAS; 0 = no discomfort, 10 = extreme discomfort).

Patient-reported pain intensity assessed using the Visual Analogue Scale (VAS; 0 = no pain, 10 = maximum pain).

Patient-reported swelling assessed using the Visual Analogue Scale (VAS; 0 = none, 10 = maximum).

Patient-reported tooth sensitivity assessed using the Visual Analogue Scale (VAS; 0 = none, 10 = maximum).

Patient-reported gingival color assessed using the Visual Analogue Scale (VAS; 0 = very poor, 10 = excellent).

Patient-reported gingival shape assessed using a single Visual Analogue Scale (VAS; 0 = very poor, 10 = excellent)

Patient-reported tooth appearance assessed using the Visual Analogue Scale (VAS; 0 = very poor, 10 = excellent).

Patient-reported procedure-related stress assessed using the Visual Analogue Scale (VAS; 0 = no stress, 10 = extreme stress).

Patient-reported treatment satisfaction assessed using the Visual Analogue Scale (VAS; 0 = not satisfied at all, 10 = completely satisfied).

Patient-reported willingness to choose the same treatment again assessed using a dichotomous (yes/no) question.

Patient-reported willingness to recommend the treatment to others assessed using a dichotomous (yes/no) question.