Antimicrobial Photodynamic Therapy in the Endodontic Treatment of Anterior Primary Teeth With Pulp Necrosis

The tooth was the unit of randomization and analysis. Some participants contributed more than one eligible tooth and could have teeth allocated to both study arms. Each eligible tooth was independently randomized using opaque, sealed, sequentially numbered envelopes.

After coronal access and working-length determination, three sterile paper points were maintained in the root canal for 30 seconds to obtain the baseline microbiological sample (S1).

In the conventional-treatment arm, S1 collection was followed by chemomechanical preparation using K-files, 1% sodium hypochlorite, and Endo PTC. A second microbiological sample (S2) was then collected.

In the aPDT arm, S1 collection was followed by intracanal application of 0.005% methylene blue for 3 minutes. Irradiation was performed with a Therapy XT red laser in continuous-wave mode at 660 nm, with a mean radiant power of 100 mW, for 90 seconds, delivering a radiant energy of 9 J through an intracanal optical fiber. The canal was then irrigated with sterile saline, and S2 was collected. No chemomechanical preparation, instrumentation, or sodium hypochlorite irrigation was performed in the aPDT arm before S2 collection.

After S2 collection, teeth in both arms received UltraCal XS calcium hydroxide intracanal medication, a thin gutta-percha base, and provisional sealing with glass ionomer cement. After 7 days, the teeth were reopened, the intracanal medication was removed, the canals were irrigated with 1% sodium hypochlorite, and definitive root canal filling was performed using Guedes-Pinto iodoform paste. Restorative treatment was performed in a subsequent session.

Clinical assessments were performed at 7 days, 1 month, and 3 months. Radiographic assessments were performed at 1 and 3 months. Conventional rescue treatment was planned for teeth in the aPDT arm if pain, fistula, swelling, or other signs and symptoms persisted or worsened.

Inclusion criteria

• Children of either sex, aged 2 to 5 years, in the primary dentition stage.
• At least one restorable single-rooted anterior primary tooth with pulp necrosis caused by deep caries or dental trauma.
• At least two-thirds of the root remaining.
• Sufficient cooperation to allow safe clinical treatment.
• No systemic antibiotic therapy during the previous 3 months.
• Written informed consent provided by a parent or legal guardian.

Exclusion criteria

• Root resorption involving two-thirds or more of the root.
• Involvement of the permanent successor tooth crypt.
• Tooth requiring immediate extraction or not amenable to endodontic treatment.
• Compromised systemic health or uncontrolled chronic disease.
• Recent antibiotic use capable of affecting microbiological results.
• Noncooperative behavior that precluded safe clinical treatment.