Can oral ADS activity or arginine levels be a caries risk indicator? A systematic review and meta-analysis

The objective of this study was to evaluate the association between salivary and plaque arginine levels/ADS activities with dental caries. A systematic search was performed as per PRISMA statement using PubMed, Scopus, Cochrane Library, and Web of Science. Published studies that investigated adults and children (P) with caries-active status (E) and caries-free status (C), whereby arginine levels/ADS activity (O) was measured in saliva/plaque to analyze exposure-outcome association compared to the control group were deemed eligible for inclusion. Quality assessment was performed using combined Newcastle-Ottawa Scale and Modified RTI Item Bank scale. Meta-analysis was performed for effect size, precision estimation, and subgroup effects analysis. Of 233 records identified, seven (kappa = 1.00) were included for qualitative synthesis (systematic review) and four for quantitative synthesis (meta-analysis). No specific bias could be identified in five studies assessed as per the Modified RTI Item Bank scale. Two studies received lower scores on the Newcastle Ottawa scale. Plaque ADS activity in adults (effect size = 0.93, p = 0.008), salivary ADS activity in adults and children (effect size = 0.85, p < 0.001), and salivary ADS activity in adults (effect size = 0.87, p < 0.001) identified a statistically significant effect size. Subgroup analysis demonstrated non-significant variance (Q value = 0.042, p = 0.838) between saliva and plaque ADS activities of adults. The results of this review suggest the salivary and plaque ADS activities appear to be promising caries risk indicators for adults, while results remain inconclusive in children. Measuring ADS activities (saliva or plaque) can be a potential caries risk indicator in adults. The protocol was registered on PROSPERO database: CRD42017060701.