The effect of space maintainers on salivary pH, flow rate, and the oral microflora

Background: Space maintainers are used to preserve created space caused by the premature loss of primary teeth but they may also upset the oral environment and play a role in caries formation. The current research aimed to assess the impact of removable and fixed space maintainers on salivary pH, flow rate, and the oral microflora. Methods: Thirty-eight patients aged between 4 and 10 years, each of whom required a fixed (n = 19) or removable space maintainer (n = 19), were enrolled in this research. The salivary pH, saliva flow rate, salivary Streptococcus mutans, and Lactobacillus counts were measured immediately prior to the placement of the space maintainers (baseline-T0) and during the follow-up period, at the 1st (T1), 3rd (T3), and 6th (T6) month. The Wilcoxon, Mann-Whitney U test and Friedman tests were applied for statistical analyses. Results: Streptococcus mutans and Lactobacillus counts were significantly higher at the 6th month time period in comparison with the baseline scores for both groups (P < 0.001). The salivary pH and flow rates did not change significantly at any measurement period (P > 0.05). Conclusions: Space maintainers can favour caries formation by changing the oral microflora. It is advisable to warn patients and their parents of the risks and provide motivation to perform meticulous oral hygiene.