The treatment will consist of oral hygiene orientation, with brushing technique instructions and daily flossing recommendation. All patients will receive a demonstration of oral hygiene techniques. The calculus deposits on the teeth will be removed with an ultrasound equipment and curettes for root scaling and straightening13. In implants, calculus will be removed with specific curettes for use on the implant surface. Treatment will be performed in 2 to 4 sessions under local anesthesia (typically 2% mepivacaine with 1: 100,000 noradrenaline). Gracey periodontal curettes (numbers 3/4, 7/8, 11/12 and 13/14) and Mc Call for removal of the dental calculus will be used. Other biofilm-retaining factors, such as carious lesions, condemned teeth and maladaptive restorations, will be removed during these periodontal treatment sessions.

aPDT will be performed after conventional treatment, in sites with pockets greater than or equal to 5 mm. The PapaMblue® photosensitizer with 100 μM methylene blue will be deposited in the pockets with a syringe, with the bottom of the pouch in the coronal direction, and a pre-irradiation time of 1 min will be adopted, so that the PS may stain the entire bacterial biofilm. Then, the laser emitting an wavelength of 660 nm, with power of 100 mW, will be applied. The laser will be applied to the mucosa on the oral epithelium with an optical fiber (apparatus of DMC Therapy EC, São Carlos, Brazil). Irradiation will be performed until the entire peri-implanted pouch is illuminated for 2 minutes at each point. The 6 points around the implant will be irradiated and each irradiation point will present an area of 0.4 cm2, which will result in radiant exposure of 30 J/cm2 following 2 min of irradiation per point. The irradiation will have a constant power density of 250 mW/cm2.

The treatment will consist of oral hygiene orientation, with brushing technique instructions and daily flossing recommendation. All patients will receive a demonstration of oral hygiene techniques. The calculus deposits on the teeth will be removed with an ultrasound equipment and curettes for root scaling and straightening13. In implants, calculus will be removed with specific curettes for use on the implant surface. Treatment will be performed in 2 to 4 sessions under local anesthesia. Other biofilm-retaining factors, such as carious lesions, condemned teeth and maladaptive restorations, will be removed during these periodontal treatment sessions.

For the evaluation of clinical parameters, a single trained, calibrated examiner will examine 6 sites of each implant with a 15mm North Carolina millimeter probe (Hu-Friedy, Chicago, IL, USA) for the measurement of plaque index. The evaluation will be performed at the beginning of treatment, 30 and 60 days after the first application of aPDT.

For the evaluation of clinical parameters, a single trained, calibrated examiner will examine 6 sites of each implant with a 15mm North Carolina millimeter probe (Hu-Friedy, Chicago, IL, USA) for the measurement of probing bleeding. The evaluation will be performed at the beginning of treatment, 30 and 60 days after the first application of aPDT.

For the evaluation of clinical parameters, a single trained, calibrated examiner will examine 6 sites of each implant with a 15mm North Carolina millimeter probe (Hu-Friedy, Chicago, IL, USA) for the measurement of probing depth. The evaluation will be performed at the beginning of treatment, 30 and 60 days after the first application of aPDT.

For the evaluation of clinical parameters, a single trained, calibrated examiner will examine 6 sites of each implant with a 15mm North Carolina millimeter probe (Hu-Friedy, Chicago, IL, USA) for the measurement of gingival recession. The evaluation will be performed at the beginning of treatment, 30 and 60 days after the first application of aPDT.

For the evaluation of clinical parameters, a single trained, calibrated examiner will examine 6 sites of each implant with a 15mm North Carolina millimeter probe (Hu-Friedy, Chicago, IL, USA) for the measurement of loss of clinical insertion. The evaluation will be performed at the beginning of treatment, 30 and 60 days after the first application of aPDT.

The microbiological examination will be performed from subgingival biofilm samples collected from the mesial region of the peri-implant pockets of the selected implants. Two collections will be performed at each experimental site before and immediately after the aPDT and irradiation procedures. For the collection of the subgingival biofilm, a relative isolation of the teeth with cotton rollers will be performed, the supra-gingival biofilm will be removed with sterile gauze, and the subgingival biofilm sample will be obtained by inserting a sterile absorbent paper tip (no. 30) into the inside of the peri-implant pocket, being held in place for 30 s. The tips will be removed and stored in properly identified sterile plastic microtubes, with each paper cone being stored in a different microtube.

The samples will be used to determine the CFUs (Colony Forming Units).