Comparison of immediate and conventional loading protocols with respect to marginal bone loss around implants supporting mandibular overdentures: A systematic review and meta-analysis

Purpose: To compare marginal bone level changes (MBLCs) of immediately- and conventionally-loaded implants supporting a mandibular implant overdenture (IOD). Materials and methods: Both electronic (MEDLINE, PubMed, and The Cochrane Library) and manual searches were conducted for all relevant studies published from 1 January 2000 to 1 November, 2017. Randomized controlled trials (RCTs) and prospective studies with a minimum follow-up of 12 months were selected. Studies which utilized implants narrower than 3 mm were excluded from analysis. Results: Four studies met the criteria, with two evaluating horizontal bone loss. There were 70 patients in the test group (immediate loading) and 60 in the control group (conventional loading). Follow-up lasted 6-36 months, with MBLCs being interpreted from standardized periapical x-rays, panoramics or cone beam computed tomography. Each patient was given 2-3 implants. After 6 and 12 months, the differences in MBLCs were 0.04 mm (95% CI: -0.21, 0.29) and 0. 00 mm (95% CI: -0.35, 0.36) respectively. Subgroup analysis of RCTs with 2 implants revealed group differences in MBLCs as 0.13 mm (95% CI: -0.22, 0.48) and that in horizontal bone loss as 0.04 mm (95% CI: -0.02, 0.10). No statistically significant differences were identified (p > 0.05). Conclusion: The MBLCs of immediately-loaded implants for mandibular IODs seems comparable to those of conventional loading. (C) 2018 The Authors. Published by Elsevier Ltd on behalf of The Japanese Association for Dental Science.