Aim: Placement of fixed space maintainer (FSM) and removable space maintainer (RSM) may increase the risk of gingivitis in children. This study aimed to assess the effect of using FSMs and RSMs on periodontal parameters in 6–12-year olds. Materials and methods: This interventional prospective study was conducted on systemically healthy 6–12-year olds (mean age of 8 years) presenting at the Department of Pediatrics, Tehran University requiring space maintainers. The probing pocket depth (PPD), bleeding on probing (BOP), and gingival index (GI) were recorded at the baseline and 6 months after using space maintainers in the abutment teeth in patients with fixed space maintainers and in the tooth with the Adams clasp in children with removable space maintainers as well as the same teeth in the opposing jaw/quadrant as controls. Results: A significant increase in PPD was noted in distolingual and mesiolingual sites at 6 months after placement of FSM (p < 0.05). This increase was not significant for RSM at any site. A significant increase in GI and BOP was also noted at 6 months after placement of FSM and RSM (p < 0.05). Caries index did not show a significant change in FSM but caries index significantly increased following the use of RSM. Conclusion: BOP and GI increase following placement of FSM and RSM, and PPD increases in distolingual and mesiolingual areas of the banded tooth.