After random allocation, all patients received full-mouth ultrasonic debridement using an ultrasonic scaler (Profi III Bios, Dabi Atlante, Ribeirão Preto, São Paulo, Brazil) for 1 hour. Specific tips were used (Perio sub, Dabi Atlante, Ribeirão Preto, São Paulo, Brazi). PDT was performed on only one side of the mouth and the initial step was subgingival irrigation with 0.005% methylene blue dye. To avoid contamination of the control sites with the dye, the methylene blue was applied only inside the periodontal pockets and a high-powered suction device controlled the flow. Two minutes after applying the photosensitizer, the low power laser - AsGaAl (Photon Laser III - PL7336, DMC, São Carlos -São Paulo, Brazil) was applied (660 nm, 100 mW, 9 J, 90 seconds per site, 320 J/cm2).

At least two teeth (one with PD ≥ 7 mm and another with PS ≥ 5 mm) were randomly assigned (by coin toss) to one of the treatments: with (test group) or without PDT (control group). After random allocation, all patients received full-mouth ultrasonic debridement using an ultrasonic scaler for 1 hour. Specific tips were used. PDT was performed on only one side of the mouth and the initial step was subgingival irrigation with 0.005% methylene blue dye. To avoid contamination of the control sites with the dye, the methylene blue was applied only inside the periodontal pockets and a high-powered suction device controlled the flow. Two minutes after applying the photosensitizer, the low power laser - AsGaAl was applied for 90 seconds.

Photodynamic therapy associated with full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis: a randomized-controlled clinical trial Running title: Photodynamic therapy associated with periodontal debridement

An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without difference them.

An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without difference them. After 6 months, PD decreased from 5.11 ± 0.56 mm to 2.83 ± 0.47 mm in test group (p<0.05) and from 5.15 ± 0.46 mm to 2.83 ± 0.40 mm in control group (p<0.05). The CAL changed, after 6 months, from 5.49 ± 0.76 mm to 3.41 ± 0.84 mm in th test group (p<0.05) and from 5.53 ± 0.54 to 3.39 ± 0.51 mm in control group (p<0.05).