Effect of Modified Free Gingival Graft and Conventional Free Gingival Graft on Gingival Recession

This study will include individuals who come to Necmettin Erbakan University Faculty of Dentistry, Department of Periodontology for various reasons and agree to participate in the study (those who sign the 'informed consent form'). Radiographic and clinical evaluations are routinely performed during the periodontal examination of each patient applying to the periodontology clinic, and routine periodontal status records are taken and archived before and after each planned treatment.

The study was designed as a randomised controlled clinical trial in which 30 patients underwent free gingival grafting (FGG) operation and 30 patients underwent modified free gingival grafting operation (mod-FG). Clinical parameters of the patients were planned to be measured 1 week before, 1 month, 3 months and 6 months after the operation.

The following clinical measurements will be taken by a single investigator at baseline (1 week before surgery) and at 1, 3, 6 and 12 months after surgery:

• Gingival Recession Depth: The distance from the enamel-cementum border to the gingival margin will be measured with an accuracy of 0.1 mm.
• Recession width: The horizontal distance from the widest part of the recession at the enamel-cementum junction to the mesial and distal starting borders, measured with an accuracy of 0.1 mm.
• Keratised Tissue Height: The distance from the gingival margin to the mucogingival junction will be measured with an accuracy of 0.1 mm.
• Papil width: The length of the horizontal line connecting the zenith points of two neighbouring teeth, measured with an accuracy of 0.1 mm.
• Papil height: The length of the vertical distance from the papillary apex to the line passing through the zenith points of the teeth, measured with an accuracy of 0.1 mm.
• Tissue thickness: It will be measured 2 mm apical to the gingival margin in the mid-buccal region under topical anaesthesia with a root canal instrument fitted with a rubber stopper and the distance between the tip of the root canal instrument and the rubber stopper will be measured with a digital caliper.
• Pocket Depth: The distance between the base of the pocket and the free gingival margin will be measured with the help of a periodontal Williams probe at six points for each tooth and the pocket depth will be recorded.

After the initial examination, each person will be given individual oral hygiene instructions and will receive professional dental cleaning, root planing and polishing with a low abrasive polishing paste and a rubber band. Surgical treatment will be planned after adequate personal plaque control has been achieved.

The included participants will be randomly allocated into two groups: conventional free gingival graft (FGG, control) or modified free gingival graft (ModFGG, test). Random allocation will be done in a 1:1 ratio based on a computer-generated number list. Under local anaesthesia, the exposed root surfaces will be cleaned with Gracey curettes and rinsed thoroughly with saline. One of the following two procedures will be performed according to group allocation.

The primary outcome will be the reduction in gingival recession. Sample size calculation will be performed using a 5% significance level and 95% power, assuming that the critical difference in gingival recession reduction between the groups at the end of 12 months is 1.7 mm and the standard deviation is 1.2 mm.

Statistical analysis will be performed using the Statistical Package for the Social Sciences (SPSS) version 23 (IBM Corp., Armonk, NY). Data will be expressed as mean and standard deviation. Data normality will be assessed using the Kolmogorov-Smirnov test. Differences between parameter means in intra-group comparisons of SDG and modSDG groups will be evaluated using One-way ANOVA (Bonferroni post-hoc) test. Differences between the 2 groups in terms of gingival recession, changes in keratinized tissue height and probing depth, and percentage root coverage will be evaluated by regression analysis using time point and group distribution as main and interaction terms. Results will be expressed as predicted values and 95% confidence intervals. p<0.05 will be considered statistically significant.

Inclusion criteria

-volunteers aged between 18-65 years.

• To be systemically healthy.
• Not smoking.
• Individuals aged 18 years and over.
• Shallow vestibule (≤5 mm).
• The periodontal pocket depth of the tooth/teeth to be treated should be ≤3 mm and the degree of tooth mobility should be ≤1.
• There should be no cervical composite restoration and no caries-free lesions on the teeth to be treated.
• Presence of Cairo Type 1 class gingival recession on the buccal surface of at most 2 of the mandibular incisors.

Exclusion criteria

• pregnancy
• untreated periodontal disease
• parafunctional habits
• poor oral hygiene (persistent whole mouth plaque index > 20%)
• iodine allergy
• excessive dental crowding or misalignment of teeth.