Effects of Er:YAG Photobiomodulation Therapy on Wound Healing of Human Palatal Mucosa After Connective Tissue Graft Harvesting: A Pilot Study
Phase: NA
Conditions: Healing Surgical Wounds, Pain Measurement
Sponsor: University of Manitoba

 
 
 
 
Effects of Er:YAG Photobiomodulation Therapy on Wound Healing of 
Human Palatal Mucosa After Connective Tissue Graft Harvesting: 
A Pilot Study 
 
 
 
 
 
 
NCT03741062 
October 16, 2020 
 
 
 

 
STUDY PROTOCOL 
Participants 
Patients of the Graduate Periodontics Clinic at the University of Manitoba who require a 
subepithelial connective tissue graft (SECTG) utilizing autogenous donor tissue harvested from 
the palate, during the time period from Fall 2018 to Spring 2020, and who sign the consent form 
will be eligible to participate.  Patients will receive initial periodontal examination and treatment 
if necessary.  Patients must be classified as ASA I or ASA II according to the American Society of 
Anesthesiologists and demonstrate both a Full Mouth Plaque Score (FMPS) and a Full Mouth 
Bleeding Score (FMBS) <20% to be included in the study.  Patients with any contraindications for 
periodontal surgery, who are currently taking anticoagulants or corticosteroids, or who smoke 
>10 cigarettes/day will be excluded from the study. 
 
Clinical Methodology 
A computerized randomization program will assign participants to one of two groups.  Patients 
will be block-randomized to ensure a balance between all the operators.  Both groups will 
undergo SECTG surgery for root coverage utilizing an autogenous graft obtained from the 
patient’s palate.  Details regarding the preparation of the recipient site and the specific root 
coverage technique will not be dictated by the experimental protocol as they will have no effect 
on the outcomes being measured.  The palate is anesthetized with 2% lidocaine (1:100000 
epinephrine) by greater palatine nerve block, nasopalatine nerve block, and local infiltration as 
needed, ensuring not to inject anesthetic into the graft tissue.  Prior to harvesting the graft, the 

thickness of the palatal tissue at the donor site will be measured via transgingival probing (or 
ultrasound device).  Graft tissue will be harvested according to the Single-Incision Technique 
described by Hurzeler.   
Surgical Technique: The donor area of the palate is located between the root of the canine and 
the palatal root of the first molar.  Its lateral border is positioned approximately 2 mm from the 
gingival margin and its medial border is dictated by the position of the palatal neurovascular 
bundle which can be found 7, 12, or 17 mm from the cementoenamel junction of the 
correspondent teeth, depending on whether the palatal vault is shallow, average, or high, 
respectively.  A single horizontal incision, whose length corresponds to the required length of the 
graft, is made at 90° to the underlying bone approximately 2 mm from the gingival margin with 
a #15 blade.  The blade is then angled at approximately 135° to the bone and a split-thickness 
dissection is started within that first incision, towards the median of the palate.  As the incision 
is advanced, the angle of the scalpel is further flattened until it is nearly parallel to the bone 
surface.  Elevation of the overlying tissue should be avoided to reduce the risk of perforation 
while making this incision.  Split-thickness dissection continues until the necessary dimensions of 
the graft are obtained, ideally maintaining 1.0-1.5 mm of overlying tissue.  The SECTG is separated 
from the surrounding tissue via incisions to the bone surface at the mesial, distal, and medial 
borders of the graft.  The graft is detached from the bone with a periosteal elevator and placed 
on a saline-soaked gauze until it is transferred to the recipient site.   
The length, width, and thickness of the graft, the thickness of the remaining palatal tissue, and 
the length of the palatal incision will be measured with digital calipers to the nearest 0.1 mm.  
Palatal incisions will be closed with cyanoacrylate.  Immediately following completion of the 

surgical procedure, Group A will receive PBM treatment of the donor site with Er:YAG laser 
according to the parameters shown to induce maximal proliferation of human gingival fibroblasts 
(Energy Setting: 80 mJ, Pulse Rate: 25 Hz, Duration: 30 s).  Group B will receive sham treatment 
with the laser unit turned off. 
During all sessions of laser treatment, the manufacturer-recommended safety precautions will 
be stringently adhered to. The clinician, patient, and any other individuals inside the operatory 
must always wear Laser Safety Glasses designated for use with Er:YAG lasers.  Whenever possible, 
the individuals present within the operatory will be limited to the patient and those directly 
involved with the procedure (i.e. the clinician and assistant).  The activated laser should never be 
directed anywhere other than the intended site of treatment.  If the operator, patient, or anyone 
else in the operatory suspects they may have incurred damage to their eyes or skin, they should 
be examined by a dermatologist and/or ophthalmologist.  A sign of notification that laser surgery 
is in progress will be placed at the entrance of the operatory.  The Er:YAG laser is not intended 
for use on patients who have a pacemaker or implantable cardioverter defibrillator, however 
these patients would not fit the inclusion criteria of ASA I and ASA II classification and thus would 
already be precluded from participation in the study.  The laser unit should not be used in the 
presence of combustible anesthetic or an elevated concentration of oxygen.  If the administration 
of oxygen is absolutely necessary, it will be ensured that there is no leakage of oxygen and the 
oxygen delivery tube will be protected with a non-combustible cuff. 
Both groups will receive 2 g of Amoxicillin (or 600 mg of Clindamycin in cases of penicillin allergy) 
and 400 mg of Ibuprofen immediately following surgery, in addition to the standard post-
operative instructions given to patients at the U of M Graduate Periodontics Clinic.  This includes 

application of an ice pack for the first 24 hours, BID rinsing with 0.12% Chlorhexidine, avoiding 
the surgical sites during oral hygiene, avoiding hot foods and liquids, avoiding hard and crunchy 
foods for 24 hours after surgery, refraining from smoking for two weeks and avoiding sucking on 
straws or spitting.  Patients will also be provided with a bag of 30 200-mg Ibuprofen tablets.  They 
will be given a Visual Analogue Scale (VAS) questionnaire to rate their post-operative pain from 
0 to 10 for each night of the first post-operative week. 
At the one-week post-operative appointment, the participants will return their VAS 
questionnaires and any remaining Ibuprofen tablets.  They will be asked to fill out a modified Oral 
Impacts on Daily Performance (OIDP) questionnaire to assess the effect of the palatal wound on 
their oral-health related quality of life during the first post-operative week.  A clinician who did 
not perform the surgery and is blinded to which treatment group the patient belongs will assess 
the donor site at the one- and two-week post-operative appointments according to a modified 
early-wound healing index (MEHI) proposed by Fickl (a variation of the EHI originally conceived 
by Wachtel) as well as the healing index (HI) of Landry, Turnbull and Howley.  Participants will 
return for a six-week post-operative appointment, during which tissue thickness at the donor site 
will be measured via bone sounding and a histological specimen will be harvested with a tissue 
punch.  Tissue samples will immediately be submerged in a solution of 10% neutral buffered 
formalin.  Clinical photographs will be taken at all appointments. 
 
Risks 
There is the risk in both the test and control groups of post-operative complications that are 
associated with any periodontal surgery including intraoral pain or discomfort, bleeding, 

infection, swelling and bruising.  There is also a risk that the desired outcome, either partial or 
complete root coverage (depending on the severity and classification of the initial recession 
defect), may not be achieved by the surgical procedure. 
 
Potential Benefits 
If Er:YAG photobiomodulation of the palatal donor site results in improved and/or faster healing 
of the tissue or less post-operative discomfort, then patients requiring SETGs will benefit from a 
shorter and more pleasant healing period following their surgery.  Also, as the effects of Er:YAG 
PBM on healing have never been investigated in human studies, the information gained from this 
study would help direct future research on this topic. 
 
Consent Process 
Patients of the Graduate Periodontics Clinic at the University of Manitoba who require SECTG 
and who meet the eligibility requirements will be asked personally if they would like to be a part 
of the project.  After being given a brief description of the research, if the patient is interested, 
they will be provided a written summary of the study and a consent form to sign if they would 
like to take part. 
 
Data Security 
All data will be recorded based on the subject’s assigned number after they have agreed to 
participate and have signed the consent form.  Their names and contact information will be 
stored in a secure, locked location at the U of M Graduate Periodontics Clinic.  Findings from the 

study may be published or presented in a public forum.  Participants’ names will not be used and 
no identifying details revealed. 
 
STATISTICAL ANALYSIS PLAN 
The study will be blinded at the level of data collection and data assessment.  The primary 
outcome for this study is the patients’ post-operative discomfort from the palatal donor site 
during the first week following surgery.  This is assessed by VAS scores and analgesic 
consumption.  Friedman’s two-way ANOVA test will compare the change in VAS scores over time 
within each treatment group.  Mann-Whitney U test will compare the difference in VAS scores 
between the two groups at each time point as well as the differences in total analgesic use 
between the two groups.  The secondary outcomes are healing of the donor site and the palatal 
wound’s effect on the patients’ OHQoL.  Healing is assessed by MEHI and HI scores and by tissue 
thickness.  Wilcoxon Signed Ranks test will compare the change in MEHI and HI scores from week 
one to week two within each treatment group.  Mann-Whitney U test will compare the 
differences in MEHI and HI scores between the treatment groups as well as the differences in 
tissue thickness at six weeks post-operatively between the groups.  OHQoL is assessed by OIDP 
scores.  The differences in OIDP scores between treatment groups is compared with Mann-
Whitney U test.  The level of significance is p £0.05.  IBM SPSS Statistics for Windows (Version 
25.0) is used for analysis.