Effect of chemomechanical preparation associated with photodynamic therapy in the reduction of microbial, LPS, LTA, substance p and pro-inflammatory cytokines in primary endodontic infection

Abstract

Lipopolysaccharide (LPS) or endotoxin is the main virulence factor of Gram-negative bacteria and is able to stimulate cells to produce pro-inflammatory cytokines involved in periapical tissue destruction, while lipoteichoic acid (ATL) is one of the virulence factors of Gram-positive bacteria. Photodynamic therapy (PDT) is a complementary method of disinfecting the root canal (RC), in addition to being used to treat several types of pain. Thus, the objectives of this work are: a) to study the microbiota of the RCs before and after the chemo-mechanical preparation (CMP) (experimental and control groups),after PDT (experimental group), 07 days after CMP by the Checkerboard method; b) to monitor the effect of CMP(experimental and control group) and PDT (experimental group) on cultivable bacteria levels by counting colony-forming units (CFU / mL); c) to evaluate the levels of LPS, LTA, substance P and pro-inflammatory cytokines IL1-² and TNF-± from the RCs before and after CMP (experimental and control groups), after PDT (experimental group) and 07 days after CMP (experimental ad control groups); d) to correlate clinical findings with microbiological content, levels of LPS, LTA, substance P and pro-inflammatory cytokines IL1-² and TNF-±; e) to monitor the reduction of a possible postoperative pain with and without the use of PDT. Twenty patients with teeth with necrotic pulp and periapical lesion will be selected, randomly divided into two groups: control group (n =10) conventional endodontic treatment without PDT, and the experimental group (PDT, n =10), where after CMP, PDT will be performed. The samples from CRs will be collected with sterile/pyrogenic paper cones and then will be frozen for analysis. The quantification of LPS will be performed using the LAL method; while the LTA, substance P and pro-inflammatory cytokines IL1-² and TNF-± by ELISA. All the results obtained, as well as the clinical aspects of the teeth involved, will be tabulated in Excel and later analyzed statistically by specific software. (AU)