Interactive Effect of Salivary Protein Carbonyl, Total Glutathione, pH, and Flow Rate on Root Caries Severity: A Case-Control Study.

Aims and Objectives: Oxidant and antioxidant components in saliva play an essential role in caries development. The purpose of the current study was to disclose the interactive effect of salivary protein carbonyl (PC), total glutathione (GSH), pH, and flow rate on root caries severity. Materials and Methods: The control and study groups consisted of 90 older adults of both genders classified into six groups: normal salivary flow rate with no root caries (control), normal salivary flow rate with incipient root caries, normal salivary flow rate with shallow root caries, hyposalivation with no root caries, hyposalivation with incipient root caries, and hyposalivation with shallow root caries. Each group consisted of 15 older adults. The study participants were selected from those patients who attended the teaching hospital at the College of the Dentistry/University of Baghdad and fit the study’s criteria. Unstimulated saliva was collected. Both salivary pH and flow rate were determined immediately. After that, saliva was subjected to biochemical analysis to determine PC and total GSH levels colorimetrically. Root surface caries was diagnosed clinically using the Root Caries Index. Data were statistically analyzed using descriptive statistics, two-way univariate analysis of variance, two-way multivariate analysis of variance, and Pearson’s correlation coefficient (α = 5%). Results: Salivary total glutathione revealed a significant interactive effect with salivary flow rate and root decay severity. Levels of salivary total GSH were significantly higher in subjects with shallow root caries than those with incipient root caries; no root caries levels of salivary PC were significantly high in the hyposalivation group, but no correlation with caries severity was found. High root caries severity was found to be associated with reduced salivary pH and flow rate. Conclusion: A significant interactive effect was recorded for salivary flow rate, pH, and total GSH on root caries severity except for salivary PC.