Activity of carvacrol and thymol in vivo against streptococcus mutans and caries experience in caries-free children : a longitudinal study

This study aimed to compare the anticaries and antimicrobial efficacy of four different substances: 20% carvacrol (CAR), 10% carvacrol in association with 10% thymol (CAR+THY), 20% chlorhexidine (CHX) and 5% sodium fluoride (NaF), in high-risk, caries-free children. One hundred and twenty children, between 36 and 71-months age, were selected from public preschools from a neighborhood in Fortaleza (Ceará). Children were classified as a high caries-risk group according to the American Academy of Pediatric Dentistry Guidelines. These children were randomly allocated into four different treatment groups. Antimicrobial agents were made as varnishes and applied every 3 months, during one year. Patients were monitored every 3 months for new caries lesions. Saliva was collected before treatment initiation (B) and after 7 (D7), 30 (D30), 90 (D90), 180 (D180) and 360 (D360) days post-treatment for MS detection. For microbiological analysis, samples were cultivated on MSB agar media and incubated at 37o C under microaerofilic conditions, during 48 hours. Bacterial colonies were confirmed as being MS through biochemical tests. MS counts were expressed in colony forming units (CFU/mL). Data was considered significant when p<0.02. When comparing MS levels between B and D7, no difference was observed between groups (p=0,032). Comparisons of the percentage MS reduction between groups (D30-D90) demonstrated a significant difference (p=0,002), with a difference between CAR versus CAR+THY (p=0.003), CAR+THY versus CHX (p=0.004), and CHX versus NaF (p=0.014). CAR+THY presented the smallest percentage reduction, while CHX presented the greatest. We observed an increase in MS in the groups treated with CHX and NaF at D360. With the exception of the NaF group, comparisons between dmfs within each group, demonstrated a significant difference between the initial dmfs and the dmfs measured 9 months after treatment initiation. A significant positive correlation between the total dental surfaces and the patient’s age was observed in all groups. No significant difference was found between caries density of the different age groups within and between groups. The dmfs scores did not differ between groups (p=0,746). In conclusion, all treatments produced significant MS reduction with great variations within and between groups, associated with low caries experience.Este trabalho buscou comparar a eficácia anti-cárie e antimicrobiana de quatro diferentes substâncias: carvacrol 20% (CAR), carvacrol 10% em associação com o timol a 10% (CAR+THY), clorexidina a 20% (CHX) e fluoreto de sódio a 5% (NaF), em crianças de alto risco e livres de cárie. Cento e vinte crianças, entre 36 a 71 meses, foram selecionadas de pré-escolas públicas de um bairro do Município de Fortaleza (Ceará), caracterizando-as segundo os critérios de risco à carie da Academia Americana de Odontologia Pediátrica como crianças de alto risco. Essas crianças foram randomicamente distribuídas nos quatro grupos de tratamento. Os antimicrobianos foram manipulados na forma de verniz e aplicados trimestralmente durante um ano. Pacientes foram monitorados trimestralmente, através de exames clínicos periódicos para avaliação do surgimento de lesões de cárie. Foram coletadas salivas antes do início do tratamento (B), após 7 (D7), 30 (D30), 90 (D90), 180 (D180) e 360 (D360) dias de tratamento para detecção de EGM. Na análise microbiológica as amostras foram cultivadas sobre Agar MSB, incubadas em estufa a 37° C, com atmosfera de microaerofilia, durante 48 horas. As colônias foram confirmadas como sendo EGM a partir de provas bioquímicas. A contagem bacteriana foi expressa em unidades formadoras de colônias (UFC/mL). Dados foram considerados significativos quando p