The Efficacy of De-epithelialized Free Gingival Graft on Treatment of Multiple Gingival Recessions With Tunnel Technique

The predictable treatment of multiple adjacent gingival recessions (MAGRs) represents a major challenge in periodontal plastic surgeries due to MAGRs' complicated predisposing anatomic features, such as thin gingival phenotype or limited keratinized tissue. The present study aimed to investigate the clinical efficacy and postoperative morbidity of de-epithelialized gingival graft (DGG) compared to subepithelial connective tissue graft (SCTG) on the treatment of multiple adjacent gingival recessions (MAGRs) with tunnel technique (TUN). A total of 38 patients, who have been referred to the Gazi University Faculty of Dentistry Department of Periodontology, were randomly assigned to receive TUN in combination with either DGG or SCTG. Clinical measurements were recorded at baseline and at 3, 6 and 12 months after surgeries. Immediately after surgery, a questionnaire was given to each patient evaluating postoperative pain, patients' discomfort, sensitivity and bleeding at 1, 2, 3, 7, 14 and 28 days after surgery. Moreover, the characteristics of the grafts harvested by these two different techniques were evaluated histopathologically and histomorphometrically.

The predictable treatment of multiple adjacent gingival recessions (MAGRs) represents a major challenge in periodontal plastic surgeries due to MAGRs' complicated predisposing anatomic features, such as thin gingival phenotype or limited keratinized tissue, variations in the depth and width of the adjacent recession defects, shallow vestibules and high frenum attachments. Furthermore, in these cases, wound healing is often more difficult due to factors such as larger avascular surface and poor blood supply.

The coronally advanced flap (CAF) or the tunnel technique (TUN) with graft-based subepithelial connective tissue procedures have been reported to be the most predictable methods for the treatment of MAGRs. On account of the advantages of TUN, including superior blood supply and advanced wound healing owing to its conservative characteristics associated with the flap elevation without papillae dissection or vertical releasing incisions, this approach has recently achieved popularity compared to other methods.

Although the use of connective tissue grafts (CTGs), together with various surgical techniques, has been accepted as "the gold standart" for the treatment of GRs, some disadvantages of CTG are underlined. Limited donor tissue in the cases where inadequate amount of palatal tissue thickness and/or a bigger dimension of CTG is needed, as in the treatment of MAGRs are claimed to be among those disadvantages (Zucchelli et al., 2010). Moreover, subepitelial CTG (SCTG), either harvested by 'trap-door' (TD) or 'single-incision' (SI) approaches, have been frequently associated with post-operative pain and discomfort, as well as palatal flap necrosis/dehiscence at the donor site.

To overcome these limitations, and obtain a firmer and uniform CTG, de-epithelializing of the free gingival grafts (FGG) have been proposed, especially when palatal fibromucosal tissue thickness is inadequate (≤2.5 mm) and a large graft dimension in apico-coronal or mesio-distal directions is required. De-epithelialized gingival graft (DGG) have also been suggested to have less prone to post-operative shrinkage, because of obtaining larger amount of collagen-rich connective tissue from lamina propria, minimal amount of fatty/glandular tissue and less number of medium to large vessels. Previously it was reported that DGG applied with the TUN presented better manuplation in recipent area and reduced postoperative morbidity compared to a conventional CTG, and resulted in a successful root coverage outcome with increased both width and thickness of the keratinized tissue in the treatment of MAGRs. In a randomized clinical trial (RCT), Zuchelli et al. found no significant differences regarding post-operative pain and root coverage outcomes when compared SCTG and DGG in combination with CAF in the treatment of single or multiple GRs. However, a significant difference was observed in terms of keratinized tissue thickness (KTT) in favor of DGG, and this finding was attributed to the its characteristics of better stability, low shrinkage rates and to allow the incorporation of the portion of connective tissue closest to the epithelium. Despite all biologically advantages of DGG, there is scarce information in the literature on its clinical significance in combination with TUN compared to conventional CTG procedures in the treatment of MAGRs. Therefore, the present study aimed to investigate the clinical efficacy and postoperative morbidity of DGG compared to SCTG on treatment of MAGRs with TUN. The primary objective was to assess the root coverage outcomes of DGG versus SCTG with TUN at 1-year postoperatively. The secondary objectives were to evaluate postoperative patient morbidity of these procedures and the characteristics of the grafts harvested by these two different techniques histopathologically and histomorphometrically.

Eligibility Criteria:
Inclusion Criteria:

* • Age between 18 - 60 years,

  * Non-smoker and systemically healthy,
  * No active periodontal disease,
  * Presence of at least two single-rooted teeth with Miller class I and/or II (RT1) (Cairo, Nieri, Cincinelli, Mervelt, \& Pagliaro, 2011; Miller, 1985) buccal gingival recession defects ≥2 mm in depth
  * Full mouth plaque and bleeding score of \<15% and no probing depths \>3 mm,
  * Absence of non-carious cervical lesions (NCCLs) and non-detectable cemento-enamel junction (CEJ) at the defect sites,
  * No history of previous periodontal plastic surgery at the affected sites.

Exclusion Criteria:

* • Presence of caries lesions or restorations in the cervical area,

  * Intake of medications which impede periodontal tissue health and healing,
  * Medical contraindications for periodontal surgical procedures,
  * Pregnancy and lactation.