Photodynamic Therapy as an Adjunct to Non-Surgical Periodontal Therapy in Stage II Periodontitis

Detailed Description Periodontitis is a multifactorial inflammatory disease driven by a dysbiotic subgingival microbiome. Despite non-surgical periodontal therapy (NSPT) being the gold standard, complete bacterial elimination is not always achieved, and residual periodontal pathogens such as Porphyromonas gingivalis and Treponema denticola can persist post-treatment. This has led to the exploration of adjunctive therapies to enhance clinical outcomes.

Antimicrobial photodynamic therapy (aPDT) is a non-antibiotic adjunct that uses a photosensitizing dye activated by laser light of a specific wavelength. Upon activation in the presence of oxygen, the dye generates cytotoxic reactive oxygen species and singlet oxygen, which disrupt bacterial cell membranes and DNA. Indocyanine green (ICG), a near-infrared photosensitizer with peak absorption in the 800-830 nm range, demonstrates high uptake among key periodontal pathogens and carries no risk of inducing antimicrobial resistance.

Study Rationale:

Current systematic reviews on aPDT as an adjunct to NSPT report contradictory findings, often attributed to heterogeneous study designs, mixed periodontitis staging, and short follow-up periods. This study addresses these limitations by focusing exclusively on a well-defined patient population with Stage II periodontitis and employing a split-mouth design to minimize inter-subject variability.

Intervention Protocol:

Control sites (NSPT alone):

Supragingival and subgingival debridement was performed using an ultrasonic scaler, followed by subgingival root instrumentation using Gracey curettes (11/12). A customized acrylic stent with a UNC-15 mm periodontal probe was used to standardize probing measurements.

Test sites (NSPT + aPDT):

Following NSPT, indocyanine green dye was reconstituted at a concentration of 5 mg/ml and delivered into the periodontal pocket via a 27-gauge needle, placed to the base of the pocket and withdrawn coronally while injecting. The photosensitizer was then activated using an Elexxion AG 810 nm diode laser, with the fiber tip moved in an apico-coronal direction parallel to the root surface within the pocket.

Randomization:

Sites were randomly allocated to test or control groups using a split-mouth design, ensuring contralateral teeth were assigned to different treatment groups.

Follow-up:

All clinical parameters - probing pocket depth (PD), clinical attachment level (CAL), gingival recession, and bleeding on probing (BOP) - were recorded at baseline and at three months post-treatment by a calibrated examiner using standardized acrylic stents.

Inclusion criteria

• - Adults aged 18 years and older
• Diagnosis of Stage II periodontitis according to the 2018 classification of the World Workshop of Periodontology (AAP/EFP)
• At least two non-adjacent sites with interproximal probing pocket depth of 4-5 mm
• Interproximal clinical attachment loss of 3-4 mm at affected sites
• Willing and able to provide written informed consent

Exclusion criteria

• Periodontal therapy including scaling and root debridement within the last 12 months
• Antibiotic use or regular use of mouthwash in the 3 months prior to enrollment
• Pregnancy
• Any systemic condition that may affect periodontal healing (e.g. uncontrolled diabetes, immunocompromised states)
• Regular use of hormonal contraceptives
• Smoking more than 10 cigarettes per day