Investigation on the effect of antimicrobial photodynamic therapy as an adjunct for management of deep caries lesions-study protocol for a randomized, parallel groups, controlled clinical trial.

Background: Alternatively to conventional treatments, chemo-mechanical caries removal agents can be used. A modality of treatment that has been increasing in dentistry is antimicrobial photodynamic therapy (aPDT). Bixa orellana is being researched for application in aPDT. This protocol aims to determine the effectiveness of aPDT with Bixa orellana extract in deep caries lesions.

Methods: A total of 160 teeth with deep occlusal dental caries will be selected and divided into 4 groups: G1 - control group (Caries removal with a low-speed drill); G2 - Partial Caries Removal with Papacarie™ (Fórmula e Ação, São Paulo, SP, Brazil); G3 - Partial Caries Removal with Papacarie™ and application Bixa orellana extract (20%) (Fórmula e Ação, São Paulo, SP, Brazil); G4 - Partial Caries Removal with Papacarie™ and application Bixa orellana extract (20%) with LED (Valo Cordless Ultradent®, South Jordan, UT, USA) (aPDT). After treatment, all the teeth will be restored with glass ionomer cement and followed up clinically and radiographically, with evaluations at immediately, 1 week, and 1, 3, 6, and 12 months. Dentin samples before and after treatment will be analyzed microbiologically. The efficacy of treatments will be assessed with microbiological (colony-forming units, before and after carious tissue removal), radiographic (integrity of the periapical area and eventual changes in the radiolucent zones), and clinical examinations (retention of the restorative material in the cavity and occurrence of secondary caries), as well as with the time required for the procedures and the need for anesthesia during the procedures. In case data distribution is normal, analysis of variance (ANOVA) will be used for both the dependent and independent variables. In case the data distribution is not normal, the Friedman test will be used for the dependent variables. For independent variables, the Kruskal-Wallis test will be used.

Discussion: Procedures using aPDT have been developed for the treatment of dental caries, but there are few controlled clinical trials in the literature confirming its efficacy.

Trial Registration: This protocol is registered at ClinicalTrials.gov under the number NCT05236205 and it was first posted on 01/21/2022 and last updated on 05/10/2022.