Electrical Stimulation Effect on Coronally Advanced Flap

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

Sixty patients presenting gingival recession will be divided in 2 groups:

• CAF group: coronally advanced flap for root coverage and sham electrical stimulation
• CAF+ES group: coronally advanced flap for root coverage plus electrical stimulation.

All surgical procedures were performed by a single operator (MPS). The gingival recession defects were randomly treated by either the trapezoidal-type of coronally advanced flap plus connective tissue graft (CAF+CTG). In brief description, CAF treatment was performed by starting with two divergent releasing incisions lateral to the recessed area. A sulcular incision was made to unite the releasing incisions and the flap was raised beyond the mucogingival junction (MGJ) in split-full-split thickness. The connective tissue graft was removed from the palate and sutured in position. Sling sutures were placed to stabilize the flap in a coronal position 2 mm above the cement-enamel junction (CEJ), followed by interrupted sutures to close the releasing incisions.

For electrical stimulation, a unit consisting of a signal generator (WaveFactoryCo., Ltd., Tokyo, Japan), a power supply (KikusuiElectronicsCo., Ltd., Tokyo, Japan) and circuit board will be used. Conductive electrodes for electrical current application will be applied to the vestibular gingival surface on each side of the flap, at a distance of 3 mm from the relaxing incisions and an alternating current of 100 microamperes (μA) at 9 kilohertz (kHz), will be distributed in order to traverse the operated area. A single application of electrical stimulation will be given for 120 seconds, once a day for a week. The electric current will have its visualization optimized through an oscilloscope. Patients randomized to the Control Group (SHAM) will receive the simulation of the electrical stimulation (ES) process.

Clinical, esthetics, and comfort of patients parameters were assessed at 45 days, 2, 3 and 6 months after the procedure.

Quantitative data were recorded as mean ± standard deviation (SD), and normality was tested using Shapiro-Wilk tests. The probing depth (PD), relative gingival recession (RGR), clinical attachment level (CAL), keratinized tissue thickness (KTT), keratinized tissue width (KTW), and dentin hypersensitivity (DH) values were examined by two-way repeated measures ANOVA to evaluate the differences within and between groups, followed by a Tukey test for multiple comparisons when the Shapiro-Wilk p value was ≥ 0.05. Those presenting Shapiro-Wilk p values < 0.05 were analyzed using a Friedman test (for intragroup comparisons) and Mann-Whitney tests (for intergroup comparisons). Patients' esthetics and discomfort measures using visual analog scale (VAS) were analyzed by T-tests. The frequency of complete root coverage was compared using χ2 tests. Intergroup root coverage esthetic score (RES) comparisons were performed with a T-test. A significance level of 0.05 was adopted.

Inclusion criteria

• Patients presenting Miller class I or II gingival recession in the maxillary canines or premolars
• Visible cemento-enamel junction (CEJ) with pulp vitality;
• Patients presenting no signs of active periodontal disease and full-mouth plaque and bleeding score ≤20%;
• Patients older than 18 years old; probing depth ˂3 mm in the included teeth;
• Patients who agreed to participate and signed an informed consent form.

Exclusion criteria

• Patients presenting systemic problems that would contraindicate the surgical procedure;
• Patients taking medications known to interfere with the wound healing process or that contraindicate the surgical procedure;
• Smokers or pregnant women;
• Patients who underwent periodontal surgery in the area of interest;
• Patients with orthodontic therapy in progress.