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The action of photodynamic therapy on human dental plaque

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Vanessa Tessarolli
Total Authors: 1
Document type: Master's Dissertation
Press: Bauru.
Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
Defense date:
Examining board members:
Maria Aparecida de Andrade Moreira Machado; Ruy Cesar Camargo Abdo; Maria Cristina Borsatto
Advisor: Maria Aparecida de Andrade Moreira Machado

The mechanical and chemical controls of dental plaque are important methods of caries prevention. The mechanical control is efficient if its run properly and daily. It can be made by a dentist (professional cleaning) or by patients themselves (toothbrushing). The chemical control should be used additionally, when the mechanical control cant be performed properly, them the biofilm can accumulate and in consequence, there are risks of dental caries or periodontal disease. For chemical control, many antimicrobial substances are related in literature. Several studies have shown that chlorexidine (CLX) is an effective antimicrobial substance against dental plaque. However, it presents some limitations like: tooth staining, loss of taste, conditions that limit its use by prolonged periods. Therefore, the search by new alternatives in microbial control of plaque is very important for improvement the treatment. In last decades, the use of light for activation of a photosensitizer appears like an alternative treatment with antimicrobial function. This treatment is called Photodynamic Therapy (PDT), recently Photochemotherapy (PACT). In PACT, the light activates a photosensitizer that is bond in microorganism and it can kill it or inhibit its growing. If this treatment is effective on human dental plaque, it will have positive impact for Dentistry and new protocols of chemical control will be developed. The present study aim was analyze the chlorexidine effect and the PDT effect (using Toluidine blue (TBO) and Liquid Chlorophyll (LC) like photosensitizer) in human natural dental plaque formed in situ. Volunteers wore a palatal appliance containing bovine enamel blocks, where the biofilm was formed. After 48 hours, different therapies were performed on plaque: (1) distilled water: negative control; (2) CLX; (3) Laser irradiation; (4) TBO; (5) TBO + Laser; (6) CL; (7) CL + Laser. The plaque samples were collected and dispersed. Next, serial dilutions were prepared and seeded onto different culture broth for the determination of the number of colony-forming units per gram (CFU/g) of total microorganisms, total Streptococcus, Streptococcus mutans, Lactobacillus and C. albicans. Samples were stained with acridine orange to analyze cells viability. The results can reveal only information about total microorganism and total Streptococcus. When the groups (2-7) were compared with the group (1), significant microbial reduction was observed only in group treated with CLX (3). The other therapies showed only a discrete reduction in relation of group (1). The cell viability showed similar results in all groups. Therefore, the CLX proved its antimicrobial effect. More studies are necessary for exact evaluation of effect of TFD on dental plaque human. (AU)

FAPESP's process: 08/07396-9 - Phododynamic therapy action in human dental biofilm
Grantee:Vanessa Tessarolli
Support type: Scholarships in Brazil - Master