The aim of the present study was to evaluate the influence of LLLT on the recovery of the palatine donor site wounds after harvest connective tissue graft.

This was a prospective, parallel and controlled clinical trial. The population evaluated in this study was selected at Science and Technology Institute - ICT - São José dos Campos, College of Dentistry

The selected patients were randomly allocated (by a computer generated list) into:

• Group 1 (Test, n=16): Periodontal surgery for root coverage through connective tissue graft and LLLT on donor site.
• Group 2 (Control, n=16): Periodontal surgery for root coverage through connective tissue graft and LLLT SHAM on donor site.

Surgical procedure was performed by one surgeon. The gingival recession defects were treated by connective tissue graft technique. A connective tissue graft was removed from palate mucosa following Bruno technique. Briefly, a first incision on the palate was performed perpendicularly to the long axis of the teeth, 2 to 3 mm apical to the gingival margin. The mesiodistal length of the incision was determined by the length of the graft required to cover the recession. Since the selected recessions were in maxillary canines and premolars, the length of the graft vary minimally (10-12mm). The second incision was made parallel to the first one, 1-2mm apically, and parallel to the long axis of the teeth in order to separate the subepithelium connective tissue from the epithelial layer. The incision is carried far enough apically to provide a 7mm height of connective tissue to cover the denuded root surface. Afterwards, another incision parallel to the long axis of the teeth, starting from the first incision was performed to separate the subepithelium connective tissue from the periosteum. Then, the connective tissue graft was removed from the palate as atraumatically as possible. Single sutures were made on the palate (4-0 silk) and the graft was sutured on the receptor site

Clinical parameters were assessed at baseline and 7, 14, 45, 60 and 90 days post-operatively

Statistical Analysis The null hypothesis considered in the study was the absence of difference in the clinical parameters between the different groups. For data analysis, the statistical program was used. The demographic and clinical data were compared between the groups using Student's t-test. The data were first analyzed for homogeneity using the Shapiro-Wilk test, which indicated non-normal distribution. . Those presenting Shapiro-Wilk p values < 0.05 were analyzed using a Friedman test (for intragroup comparisons) and Mann-Whitney tests (for intergroup comparisons). For remaining wound area, tissue colorimetry, tissue thickness, and post-operative discomfort parameter analysis, Two Way Repeated Measures ANOVA was performed for intra and intergroup analysis. T-test was used for intergroup comparison of number of analgesics taken. Presence or absence of scar was measured by Q-square test. For all tests significance level of 5% was used.

Inclusion Criteria:

• Patients that were 20 to 70 years old, both genders; presenting gingival recession Class I or II Miller, on vital canines or pre-molars, palatine region (donor site) with no pathological or morphological alterations; patients who agreed with and signed the formal consent to participate in the study, after receiving an explanation of risks and benefits, by an individual who was not a member of the present study (Resolution no. 196 - October, 1996, and Ethics and Code of Professional Conduct in Dentistry - CFO 179/93).

Exclusion Criteria:

• Patients with systemic problems that contraindicated surgical procedure; patients under medication that would interfere with the wound healing; patients who smoked; patients who were pregnant or lactating; patients who had had periodontal surgery on the study area.