Effectiveness of the use of lasers or chlorhexidine on S. mutans reduction inartificialcaries lesions

• Grant number: 17/15191-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2017
• End date: September 30, 2018
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Patricia Moreira de Freitas Costa e Silva
• Grantee: Renan Felip Neres Santos
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In order to preserve the dental structure, dentin remnants affected by caries may be left after removal of the carious tissue. Disinfectant techniques are used for the removal of bacteria after cavity preparation. In addition, caries removal methods, less invasive than the traditional use of high-speed drills, have been introduced, such as high power lasers. In the context of microbial reduction, high power lasers (photothermal effect) and low power lasers associated with photosensitizers (antimicrobial photodynamic therapy) can be used. The objective of this in vitro study is to evaluate the use of lasers or chlorhexidine on microbial reduction in artificially induced caries lesions. Forty human dentin discs will be analyzed according to surface treatment (n = 10): G1 - no treatment; G2 - 2% chlorhexidine digluconate; G3 - antimicrobial photodynamic therapy 1 (low power laser 660 nm + 0.01% methylene blue); G4 - antimicrobial photodynamic therapy 2 (low power laser 660 nm + 0.005% methylene blue). The dentin affected by caries will be induced by an artificial model developed with S. Mutans, with a lesion depth of 500 ¼m. Carious dentin will be collected by a sterile carbide spherical drill positioned at the greatest depth of the lesion (500 ¼m). The primary outcome (quantitative evaluation) is the reduction of bacteria, performed by the calculation of colony forming units (CFU) for each of the proposed treatments. Statistical analysis will be done to compare bacterial reduction within groups. (AU)