This is a parallel-group, randomized controlled clinical trial aimed to evaluate the clinical and microbiological effects of the adjunctive topical use of diode laser and green indocyanine in the full-mouth ultrasonic debridement of patients affected by periodontitis.

Periodontitis is a chronic inflammatory disease affecting the supporting tissues of the teeth and is primarily caused by the subgingival inflammation induced by the bacterial oral biofilm. Several risk factors may condition its development and progression and, if untreated, periodontitis may lead to tooth loss and severe functional and aesthetic impairments.

A central role in the non-surgical treatment of periodontitis is played by the manual and ultrasonic debridement of supra and subgingival bacterial deposits. The benefit of a fully ultrasonic approach lies in the knowledge that removing radicular structure is not a prerequisite for periodontal healing.

However, non-surgical therapy has limitations due to limited access to some sites (furcation areas, concavities, grooves, distal sites of molars, and deep pockets), which may impair periodontal healing due to the persistence of pathogens and subsequent recolonization. In this context, the use of diode laser in combination with photoactivated solutions has been proposed as an adjunct treatment to conventional periodontal therapy to enhance the antibacterial effect and improve clinical effects, especially in areas of difficult access.

In view of theme relevance and the existence of conflicting results in the literature, the aim of the present parallel-group, randomized controlled clinical trial is to evaluate the clinical and microbiological effects of the adjunctive topical use of diode laser and indocyanine green (DLIG) in the full-mouth ultrasonic debridement (FMUD) of patients affected by periodontitis.

24 patients will be treated by FMUD and, after 7 days, randomly allocated half to the test and a half to the control group. In the test group, patients will receive an adjunctive treatment in periodontal sites with an initial pocket depth > 4mm consisting of the use of a diode laser device (Fox ARC, Sweden & Martina, Due Carrare, Italy) after pocket irrigation by a solution of indocyanine green (Emundo®, Sweden&Martina, Due Carrare, Padova, Italy), whereas the patients in the control group will receive sham treatment (ST). The same treatment will be repeated three weeks after in both the test and control groups.

Clinical assessment and microbiological analysis of subgingival plaque will be performed at baseline and after 3 and 6 months.

Inclusion criteria:

• Diagnosis of moderate to severe periodontitis
• Systemic health

Exclusion criteria:

• Systemic diseases requiring antibiotic prophylaxis or other systemic medication that could affect the patient's clinical response
• Periodontal treatment within the last 12 months or systemic antibiotic intake in the last 3 months
• Pregnancy

The patients in the control group are treated by the same operator and received a sham laser treatment in which, after pocket irrigation with the photosensitizer solution, the laser tip is inserted in the pockets but the laser unit is kept off.