Relationship among salivary carbonic anhydrase VI activity, alpha-salivary amylase, buffering capacity, salivary flow rate and dental caries in children

Author(s)

Thayse Rodrigues de Souza

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2016-06-24

Examining board members

Marinês Nobre dos Santos; Alberto Carlos Botazzo Delbem; Thais Marchini de Oliveira Valarelli; Paula Midori Castelo; Michelle Franz Montan

• Advisor: Marinês Nobre dos Santos

Abstract

The carbonic anhydrase VI (CAVI) and ?-amylase (SAA) enzymes are present in saliva. AC VI is responsible for catalyzing the main reaction buffering the oral cavity. SAA is associated with the pellicle and biofilms formation and starch metabolism. There are no reports in the literature that have longitudinally investigated the relationship between AC VI and dental caries and a cross-sectional study to investigate the SAA activity after a cariogenic challenge. The objectives of the Chapter 1 of this thesis were: Determine the stimulated salivary flow (SSFR), buffer capacity (BC) and CA VI activity in the saliva of children with caries and caries-free before and after rinsing with a sucrose solution to 20% and to investigate the relationship of these variables with dental caries in a longitudinal study of one year of follow-up. And of the Chapter 2: Investigate the SAA activity in saliva of children with caries and caries-free before and after rinsing with a sucrose solution at 20% and its relationship with SSFR, BC and dental caries in a cross-sectional study. Were allocated to the study of Chapter 1 47 children 48-78 months age, divided into three groups after calculation of caries increment after one year: caries free group (CF), caries lesion group (CL) and arrestment caries group (AC). And in Chapter 2, 38 children aging 48-77 months old, divided into two groups: caries lesion group (CL) and caries free group (CF). The activity of CA VI was quantified by zymography. The SSFR was expressed in mL/min. The BC was measured by Ericsson¿s method. The SAA activity was analyzed by the enzyme kinetic assay. Wilcoxon test and the Kruskal-Wallis test for paired comparisons of the values of CAVI before and after the rinses and comparison between groups respectively. To SSFR and BC data were employed the tests mentioned above in the two Chapters. The Student t test paired and independent were employed to the SAA data. It was also performed Spearman correlation analysis (? = 0.05). The results of chapter 1 show that CA VI activity significantly decreased after the cariogenic challenge at the CF group in baseline and follow-up and at AC group only at the follow-up (p= 0.037, p=0.028 e p=0.027, respectively). No change in CA VI activity was found at the two periods of the study in CL group. Salivary CA VI activity before rinse at the baseline shows also a negative correlation with dental caries at the baseline before and after rinse and at the follow-up before the rinse in the CL group (r=-0.609, p=0.004 e r=-0.516, p=0,020, r= -0.545, p=0.013, respectively). A negative correlation was found between dental caries at baseline as well at follow-up and BC after rinse at follow-up (r=-0.345, p=0.017 e r=-0.303, p=0.038 respectively). The results of Chapter 2 shows that the CL group exhibited a significant increase on SAA activity after rinse (p=0.001), and significantly differed from CF group (p=0.033). The results of the two Chapters show a significant increase and decrease of SSFR and BC respectively after the sucrose rinse solution in both groups. It is concluded that the AC VI activity possible participates on the oral pH control after a cariogenic challenge, particularly in children with caries. It is also suggested possible involvement of SAA as a facilitator of the decay process due to the increase of its activity when the children were submitted to a cariogenic challenge in the group of children with caries (AU)

• FAPESP's process: 12/02516-1 - Relationship among Salivary Carbonic Anhydrase VI Activity, Buffer capacity and Flow Rate and Dental Caries in Primary Dentition - Longitudinal study in 36 to 72- month-old preschool children
• Grantee: Thayse Rodrigues de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate