Effects of Laser Stimulation on Wound Healing of Human Palatal Tissue

The purpose of this study is to assess the effects of photobiomodulation (PBM) with an Er:YAG laser on the palatal donor site following subepithelial connective tissue graft (SECTG) surgery. Patient-centred outcomes and wound healing will be compared between a control group, who receives no laser treatment, and the test group receiving PBM therapy. It is hypothesized that laser stimulation will have a beneficial effect on the patient's post-operative experience as well as the healing of the tissues.

The study is a randomized clinical trial comparing palatal donor sites that receive PBM with an Er:YAG laser and palatal donor sites receiving no additional treatment, following SETG surgery. A computerized randomization program will assign patients to one of two groups. Participants will be block-randomized to ensure balance between the operators.

The palate is anesthetized with 2% lidocaine (1:100000 epinephrine) by greater palatine nerve block, nasopalatine nerve block, and local infiltration. The thickness of the tissue at donor site of the palate is measured by transgingival probing ("bone sounding"). The palatal tissue is harvested from the area bordered mesially by the root of the canine and distally by the palatal root of the first molar, extending laterally to approximately 2 mm from the gingival margin and medially far enough to obtain an adequate area of tissue for the required size of the graft while ensuring not to encroach on the palatal neurovascular bundle.

A horizontal incision, corresponding to the necessary length of the graft, is made at 90 degrees to the bone approximately 2 mm from the gingival margin. Within this first incision, the scalpel is angled at approximately 135 degrees and a split-thickness dissection of the palatal tissue is extended medially. As the scalpel is advanced, the angle of the blade is further flattened until it is nearly parallel to the surface of the bone. The incision is extended until the necessary dimensions of the graft tissue are reached. Incisions are then made to the bone at the mesial, distal, and medial borders of the graft. The donor tissue is detached from the bone with a periosteal elevator and placed on a saline-soaked gauze.

The length, width, and thickness of the graft, the thickness of the remaining flap of palatal tissue, and the length of the palatal incision will be measured with digital calipers to the nearest 0.1 mm. The palatal incision will be closed with cyanoacrylate. Immediately following completion of the surgical procedure, Group A will receive PBM of the donor site and Group B will receive sham treatment with the laser unit turned off. The parameters used for PBM will be those shown to induce maximal proliferation of gingival fibroblasts using an Er:YAG laser: Energy \[80 mJ\], Duration \[30 s\], and Pulse Rate \[25 Hz\].

Post-operatively, both groups receive 2 g of Amoxicillin (or 600 mg of Clindamycin in cases of penicillin allergies) and the standard post-surgical instructions given to patients at the Graduate Periodontics clinic. Patients are then provided a Visual Analog Scale (VAS) questionnaire to rate their pain from 0-10 each night for 1 week and 30 Ibuprofen (200 mg) tablets.

Patients will be followed up with at 1-week, 2-week, and 6-week post-operative appointments. Photographs will be taken at all appointments. At the first appointment, participants will return their completed VAS and any remaining Ibuprofen tablets. The donor site will be examined by a clinician who did not perform the surgery and assessed according to Fickl's Modified Early-Wound Healing Index (MEHI) and Landry's Healing Index (HI). Patients will also answer a modified Oral Impacts on Daily Performance (OIDP) questionnaire. At the 2-week appointment, the palate will again be evaluated by the same operator and assessed according to the MEHI and HI. At the 6-week appointment, the donor site will be anesthetized with local infiltration of 2% lidocaine (1:100000 epinephrine), ensuring not to inject anesthetic into the tissue overlying where the graft was harvested from. Tissue thickness at the donor site will be measured via transgingival probing, in the same method as was used pre-operatively, and a histological specimen of the tissue will be harvested and placed in 10% neutral buffered formalin. Barring any ongoing post-surgical complications at this point, the patient's participation in the study is now complete.

Eligibility Criteria:
Inclusion Criteria:

* ASA I or II
* Full Mouth Plaque Score (FMPS) \< 20%
* Full Mouth Bleeding Score (FMBS) \< 20%

Exclusion Criteria:

* Any contraindications for periodontal surgery,
* Anticoagulant usage
* Corticosteroid usage
* Smoking \> 10 cigarettes/day.