Comparison of Two Different Low-level Laser Intensity Protocols on the Healing of Palatal Wounds

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

Patients were assigned to one of the three treatment groups:

• Group 60 (Test, n=18): Periodontal surgery for root coverage through connective tissue graft and LLLT application on donor site using a 60 J/cm² dose.
• Group 30 (Test, n=18): Periodontal surgery for root coverage through connective tissue graft and LLLT application on donor site using a 30 J/cm² dose.
• Group Sham (Control, n= 18): Periodontal surgery for root coverage through connective tissue graft and LLLT SHAM on donor site.

All surgeries were performed by the same expert periodontist (MPS). Before the surgical procedure, all patients were enlightened about the causes and consequences of gingival recession and prevention techniques. Factors related to the origin of gingival recession, such as toothbrush trauma and inflammation caused by biofilm, were controlled through instruction on standardized brushing technique to avoid the influence of other hygiene methods capable of promoting trauma on soft tissues. Standardized dental floss and toothbrushes were given to patients. The surgical technique adopted in the recession defects was the trapezoidal-type of CAF and the connective tissue graft was removed from palate mucosa . 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 mesial-distal length of the incision was determined by the length of the graft required to cover the recession. Because the selected recessions were in maxillary canines and premolars, the lengths of the graft varied minimally (10-12mm). The second incision was made parallel to the first one (1-2 mm apically and parallel to the long axis of the teeth) to separate the subepithelium connective tissue from the epithelial layer. The incision is carried far enough apically to provide a 7- mm height of connective tissue to cover the denuded root surface. Afterward, 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.

The evaluated parameters were wound remaining area (WRA), scar and tissue colorimetry (TC), tissue thickness (TT) and postoperative discomfort (D), evaluated at baseline and 7, 14, 45, 60, and 90 days after surgery.

Statistical Analysis: All data were expressed as mean ± standard deviation or expressed in percentages during the descriptive phase. Data were analyzed according to distribution by the Shapiro-Wilk test. For the remaining wound area, tissue colorimetry, tissue thickness, and postoperative discomfort parameter analysis, two way repeated measures ANOVA was performed for intra- and intergroup analysis. T test was used for intergroup comparison of the number of analgesics taken. The presence or absence of scars was measured by Q-square test. Statistical analysis was performed using Sigma Plot 12.0. In all tests a significance level of 0.05 was chosen.

Inclusion criteria

• Patients were 20 to 70 years old and of both genders, presenting Class I or II Miller gingival recession on vital canines or premolars in the palatine region (donor site) with no pathological or morphological alterations.
• Patients agreed to and signed the formal consent to participate in the study after receiving an explanation of risks and benefits from 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

• Were excluded patients with systemic problems that contraindicated surgical procedure
• Those under medication that could interfere with the wound healing
• Those who smoked
• Those who were pregnant or lactating, and
• Those who had had periodontal surgery on the study area.