Influence of sucrose on genotypic diversity of S. mutans in dental biofilm detected by AP-PCR, in situ and in vivo study

Author(s)

Rodrigo Alex Arthur

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2006-02-22

Examining board members

Cinthia Pereira Machado Tabchoury; Marcia Pinto Alves Mayer; Pedro Luiz Rosalen

• Advisor: Renata de Oliveira Mattos Graner; Cinthia Pereira Machado Tabchoury

Abstract

selecting acid-tolerant microorganisms. However, little is known about the influence of sucrose on genotypic diversity of Streptococcus mutans. The aim of this crossover study was to evaluate S. mutans genotypic diversity found in dental biofilm formed in vivo and in situ in the presence of sucrose and glucose+fructose. Seven days before the beginning of the experiment and throughout the entire experiment, the volunteers used a non-fluoridated dentifrice. In the beginning of the experiment, stimulated saliva was collected from the volunteers for mutans streptococci, total streptococci and total microbiota counts, and for identification of S. mutans genotypes. During the in vivo study, 7 healthy adult volunteers rinsed with distilled and deionized water, 10% glucose + 10% fructose or 20% sucrose solution, 8 x/day, during three consecutive days. Dental hygiene was suspensed in the region of upper pre-molars and molars and the biofilm formed in these teeth was collected at the end of the period. For the in situ study, which occurred in three phases of 3 days each, the same volunteers wore intra-oral acrylic palatal appliances containing 2 blocks of human sound dental enamel and dripped onto the blocks, in each phase, one of the treatments described above, 8 times per day and the biofilm formed was collected after 3 days of formation. All volunteers were submitted to all treatments. S. mutans morphological types present in biofilm and saliva were isolated, DNA was extracted and their molecular identity was confirmed by PCR with specific primers. Only one geno type was present in saliva from 85.7% of volunteers, but in the in vivo and in situ biofilms, besides this salivary genotype, others were found. Similar genotypic diversity was found in vivo compared to in situ biofilm. There was no quantitative difference in genotypic diversity of S. mutans among the experimental treatments, but glucose+fructose and sucrose harbored different genotypes compared to DDW (AU)