Photodiagnosis and Photodynamic Therapy (2015) 12, 575—580 Available online at www.sciencedirect.com ScienceDirect jou rn al hom epage: www.elsevier.com/locate/pdpdt Effects of antimicrobial photodynamic therapy and surgical endodontic treatment on the bacterial load reduction and periapical lesion healing. Three years follow up Aguinaldo S. Garcez Ph.D. a,* , Julio G. Arantes-Neto b , Debora P. Sellera b , Eduardo Rodrigues Fregnani c a São Leopoldo Mandic Dental Research Center, Campinas, SP, Brazil b Associac ¸ão Paulista de Cirurgiões Dentista, São Paulo, SP, Brazil c Hospital Sírio-Libanês, São Paulo, SP, Brazil Received 3 March 2015; received in revised form 12 May 2015; accepted 1 June 2015 Available online 10 June 2015 KEYWORDS Endodontics; Antimicrobial; PDT; Periapical surgery; Bone healing Summary Besides the advances in endodontics, there are situations in which surgery is nec- essary to retain a tooth that otherwise would be extracted. This study analyzes the microbial reduction after conventional periapical surgery followed by antimicrobial photodynamic ther- apy (aPDT) in 3 years follows up. Twenty-eight teeth needing periapical surgery were enrolled in this study. Microbiological samples were taken after: (1) accessing the lesion, (2) surgical proce- dure, and (3) aPDT. The teeth received a full mucoperiosteal flap, osteotomy with a high-speed bur, manual curettage of lesion and of the root, root-end resection and retrograde cavities prepared using ultrasonic retro-tips. After the conventional procedure the cavities received an aqueous solution of methylene blue (60 M, 3 min) and were irradiated with a diode laser  = 660 nm (6 min, 15 J). After aPDT, a retrograde filling with mineral trioxide aggregate, flap re- positioning, and sutures conventionally ended the procedure. In all the cases, a periapical X-ray exam was taken before and after the surgical procedure. The microbiological samples showed an overall significant reduction, surgical procedure achieved a mean reduction of about 3.5 log while aPDT achieved a 5 log reduction. After 36 months of follow up the patients had, in average a reduction of 78% of the periapical lesion area. It appears that surgical endodontic ∗ Corresponding author at: Rua Taquara Branca, 78 ap 36A, 02069-000 São Paulo, SP, Brazil. E-mail addresses: garcez.segundo@gmail.com (A.S. Garcez), julioarantes@ig.com.br (J.G. Arantes-Neto), sellera@terra.com.br (D.P. Sellera), eduardofregnani@me.com (E.R. Fregnani). http://dx.doi.org/10.1016/j.pdpdt.2015.06.002 1572-1000/© 2015 Elsevier B.V. All rights reserved.