Immediate and residual antimicrobial effects of adjunctive photodynamic therapy on
- 1Pontifical Catholic University of Rio Grande do Sul - PUCRS, Porto Alegre, Brazil
- 2Federal University of Rio Grande do Sul - UFRGS, Porto Alegre, Brazil
- 3Pontifical Catholic University of Rio Grande do Sul - PUCRS, Porto Alegre, Brazil; Medical and Dental Center of the Military Police of Rio Grande do Sul - CMOBM, Porto Alegre, Brazil; Corresponding author at: Graduate Program in Dentistry, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande do Sul, Avenida Ipiranga, 6681, Partenon, 90619-900, Porto Alegre, Brazil.
Abstract
Objective: To evaluate the immediate and residual antimicrobial effects of adjunctive photodynamic therapy (PDT) associated with chemo-mechanical preparation (CMP) in Enterococcus faecalis -infected human root canals, with particular emphasis on whether PDT provides a persistent antimicrobial effect after treatment. Materials and methods: Sixty-four extracted single-rooted human teeth were infected with E. faecalis and randomly assigned to four experimental groups according to treatment protocol and evaluation time: CMP-immediate ( n = 10), CMP-15d ( n = 10), CMP+PDT-immediate ( n = 10), and CMP+PDT-15d ( n = 10). Positive controls consisted of infected, untreated specimens evaluated immediately ( n = 4) or after 15 days ( n = 4), whereas negative controls consisted of non-infected specimens subjected to the corresponding experimental procedures ( n = 16). Microbiological samples were collected before treatment and either immediately or 15 days after treatment. Antimicrobial efficacy was assessed by CFU/mL counts and expressed as percentage bacterial reduction. Root canal surface contamination was evaluated by scanning electron microscopy (SEM). Percentage bacterial reduction and SEM contamination scores were analyzed using the Kruskal–Wallis test followed by Dunn’s multiple-comparisons test (α=0.05). Results: All treatment protocols produced marked bacterial reduction (>99%) compared with baseline. Although the CMP+PDT groups showed numerically greater bacterial reduction and a higher frequency of specimens with undetectable bacterial growth than the CMP groups, these differences were not statistically significant ( p > 0.05). No residual antimicrobial benefit attributable to PDT was detected after the 15-day observation period. SEM analysis confirmed significantly lower contamination scores in treated specimens than in untreated controls but showed no consistent differences between CMP alone and CMP+PDT. Conclusions: Adjunctive PDT did not provide a statistically significant additional antimicrobial benefit over conventional chemo-mechanical preparation, either immediately after treatment or after 15 days. No residual antimicrobial effect attributable to PDT was detected.
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BibTeX
@article{santos2026immediate,
title = {{Immediate and residual antimicrobial effects of adjunctive photodynamic therapy on}},
author = {Antonio José Pecinali Santos and Catherine Bandiera Zaleski and José Antônio Poli de Figueiredo and Sílvia Dias de Oliveira and Maximiliano Schünke Gomes},
journal = {Photodiagnosis and Photodynamic Therapy},
year = {2026},
month = oct,
doi = {10.1016/j.pdpdt.2026.105690},
url = {https://doi.org/10.1016/j.pdpdt.2026.105690},
note = {CC BY},
}
RIS
TY - JOUR
TI - Immediate and residual antimicrobial effects of adjunctive photodynamic therapy on
AU - Antonio José Pecinali Santos
AU - Catherine Bandiera Zaleski
AU - José Antônio Poli de Figueiredo
AU - Sílvia Dias de Oliveira
AU - Maximiliano Schünke Gomes
PY - 2026
DA - 2026/10/30
JO - Photodiagnosis and Photodynamic Therapy
DO - 10.1016/j.pdpdt.2026.105690
UR - https://doi.org/10.1016/j.pdpdt.2026.105690
AB - Objective: To evaluate the immediate and residual antimicrobial effects of adjunctive photodynamic therapy (PDT) associated with chemo-mechanical preparation (CMP) in Enterococcus faecalis -infected human root canals, with particular emphasis on whether PDT provides a persistent antimicrobial effect after treatment. Materials and methods: Sixty-four extracted single-rooted human teeth were infected with E. faecalis and randomly assigned to four experimental groups according to treatment protocol and evaluation time: CMP-immediate ( n = 10), CMP-15d ( n = 10), CMP+PDT-immediate ( n = 10), and CMP+PDT-15d ( n = 10). Positive controls consisted of infected, untreated specimens evaluated immediately ( n = 4) or after 15 days ( n = 4), whereas negative controls consisted of non-infected specimens subjected to the corresponding experimental procedures ( n = 16). Microbiological samples were collected before treatment and either immediately or 15 days after treatment. Antimicrobial efficacy was assessed by CFU/mL counts and expressed as percentage bacterial reduction. Root canal surface contamination was evaluated by scanning electron microscopy (SEM). Percentage bacterial reduction and SEM contamination scores were analyzed using the Kruskal–Wallis test followed by Dunn’s multiple-comparisons test (α=0.05). Results: All treatment protocols produced marked bacterial reduction (>99%) compared with baseline. Although the CMP+PDT groups showed numerically greater bacterial reduction and a higher frequency of specimens with undetectable bacterial growth than the CMP groups, these differences were not statistically significant ( p > 0.05). No residual antimicrobial benefit attributable to PDT was detected after the 15-day observation period. SEM analysis confirmed significantly lower contamination scores in treated specimens than in untreated controls but showed no consistent differences between CMP alone and CMP+PDT. Conclusions: Adjunctive PDT did not provide a statistically significant additional antimicrobial benefit over conventional chemo-mechanical preparation, either immediately after treatment or after 15 days. No residual antimicrobial effect attributable to PDT was detected.
SN - 1572-1000
SN - 1873-1597
ER -