Study of concentration and activity of carbonic anhydrase VI in saliva and biofilm of children in school age and its relation to tooth decay

Orientador: Marines Nobre dos Santos UchoaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A anidrase carbônica VI (AC VI) é a principal enzima responsável pela manutenção da capacidade tampão no meio bucal. Não há relatos na literatura sobre a relação entre a atividade dessa isoenzima, pH, fluxo e capacidade tampão e a prevalência de cárie, e se a atividade da AC VI pode ser empregada como indicador de risco de cárie. Os objetivos desta tese foram: 1)Realizar uma revisão sistemática da literatura 2)Determinar a concentração e atividade da AC VI na saliva e biofilme de crianças com cárie (C) e livres de cárie (LC) bem como o fluxo salivar, pH e capacidade tamponante; e 3)Investigar a relação entre essas variáveis na saliva e biofilme e a cárie dental. Para isto, 74 escolares de 7 a 9 anos foram divididos em 2 grupos. Foi realizado exame clínico, coleta de saliva e biofilme. Os ensaios da concentração da AC VI foram realizados por Elisa. A análise da atividade da AC VI por zimografia. O fluxo salivar foi expresso em mL/min. O pH foi determinado por um medidor de pH portátil, e o pH do biofilme por eletrodo específico. A capacidade tamponante da saliva foi medida eletrometricamente. Os dados foram submetidos ao teste t de Student e Mann-Whitney, além da análise de correlação de Pearson e Spearman (?=0,05). A análise bivariada foi realizada com o objetivo de verificar associações entre a variável dependente e independentes. Na modelagem multivariada, as associações entre as variáveis dependentes e independentes foram expressas como odds ratios com intervalos de confiança de 95%. Os resultados mostraram valores significativamente maiores de fluxo, pH e capacidade tampão salivar no grupo LC. O pH do biofilme também foi maior no grupo LC. A concentração da AC VI na saliva e no biofilme foi significativamente maior no grupo LC. Já a atividade da AC VI foi significativamente maior no grupo C na saliva e biofilme. Observou-se correlação negativa entre a capacidade tampão salivar e a cárie dentária. Além disso, observou-se uma correlação positiva entre a concentração e atividade da AC VI na saliva e uma correlação negativa entre a capacidade tampão e a atividade da isoenzima no grupo C. No grupo LC foi observada correlação negativa entre o pH e concentração da AC VI. Um menor fluxo salivar e uma maior atividade da isoenzima foram significativamente associados com a cárie. Para a placa dental, foi observada correlação negativa entre atividade e concentração da AC VI e entre o pH e a atividade da AC VI no grupo LC. No grupo C foi observada correlação negativa entre o pH e a concentração da AC VI. Conclui-se que a AC VI mostrou estar mais ativa na saliva e placa dental de crianças com cárie ativa. Uma maior concentração da AC VI na saliva e placa dental de crianças livres de cárie sugere que como são menos expostas a desafios cariogênicos, o sistema carbonato seria menos ativado. A AC VI na saliva e placa dentária pode ser considerada uma proteína anti-cáries, além de um biomarcador para a cárie dentáriaAbstract: The carbonic anhydrase VI (CA VI) is the main enzyme responsible for maintaining the buffer capacity in the oral environment. There are no reports in the literature on the relationship between the activity of this isoenzyme, pH, flow and buffering capacity and the prevalence of caries, and if the activity of CA VI can be employed as caries risk indicator. The objectives of this thesis were: 1) Conduct a systematic review of the literature 2) Determine the concentration and activity of CA VI in saliva and dental plaque of children with caries (C) and caries-free (CF) and the salivary flow, pH and buffering capacity; and 3) To investigate the relationship between these variables in saliva and dental plaque and tooth decay. For this, 74 students aged 7 to 9 years old were divided into 2 groups. It performed clinical examination, saliva collection and biofilm. The assays of the concentration of CA VI was performed by Elisa. The analysis of the CA VI activity by zymography. The salivary flow rate was expressed in ml/min. The salivary pH was determined by a portable pHmeter and the plaque pH with a selective electrode. The buffering capacity of saliva was measured eletrometrically. Data were subjected to Student's t test and Mann-Whitney, besides the Pearson and Spearman correlation analysis (? = 0.05). A bivariate analysis was performed in order to verify associations between the dependent and independent variables. In multivariate modeling, associations between the dependent and independent variables were expressed as odds ratios with 95% confidence intervals. The results showed significantly higher values of flow, salivar pH and buffering capacity in the CF group. The pH of the biofilm was also higher in the CF group. The concentration of CA VI in saliva and plaque were significantly higher in the LC group. The activity of CA VI was significantly higher in group C in saliva and plaque. There was a negative correlation between salivary buffering capacity and tooth decay. Moreover, a positive correlation was observed between the concentration and activity of CA VI in saliva and a negative correlation between the buffer capacity and isoenzyme activity in group C. In the CF group there was a negative correlation between pH and concentration of CA VI. A minor salivary flow and increased isoenzyme activity were significantly associated with caries. For dental plaque, it was observed negative correlation between activity and concentration of CA VI and between pH and activity of CA VI in the LC group. In the C group there was a negative correlation between pH and concentration of the CA VI. It concludes that the CA VI proved to be more active in saliva and dental plaque of children with active decay. Greater concentration of CA VI in saliva and dental plaque of caries-free children suggests that they are less exposed to cariogenic challenges, the system carbonate would be less active. The CA VI in saliva and dental plaque can be considered an anti-caries protein, as well as a biomarker for dental cariesDoutoradoOdontopediatriaDoutora em Odontologia2012/02886-3, 2012/15834-1FAPES

The protective potential of Carbonic Anhydrase VI (CA VI) against tooth decay in children: A systematic review of the literature

Carbonic anhydrase VI (CA VI) catalyzes the reversible hydration of carbon dioxide in saliva with possible pH regulation, taste perception, and tooth formation effects. Objective: The aim of this work was to undertake a systematic review regarding the relationship between the expression/activity of CA VI in saliva and in dental biofilm and caries experience. Study design: Five databases were searched until February 2020. The composition was based on the PRISMA statement and on the PICOS model. First author, year, subject characteristics, analysis performed, outcome, measures & variables were extracted. The used terms were “carbonic anhydrase VI”, “saliva”, “dental biofilm” and “dental caries”.Results: Five studies in the English language were selected for this systematic review and the main discussed topics were the expression/activity of CA VI in saliva and/or in the dental biofilm of children, and its relationship with dental caries. Conclusion: Salivary carbonic anhydrase plays an important role in the caries dynamics process since there is an association between the expression/activity of CA VI in saliva and the experience of caries. Thus, this protein can predict the risk of dental caries in young patients