Objective:To systematically investigate the different influences of Hawley’s retainer

vacuum-formed retainer and fixed lingual retainer on periodontal conditions. Methods :The related articles in Cochrane Library

Embase

Pub Med

CBM

CNKI and Wangfang database were retrieved from inception to December 2014. All articles are about the influence of the three types of retainers on periodontium. Literature from other sources was searched by hand. Review Manager 5.2 was used to conduct Meta-analysis. Results:Seven articles accorded with the inclusion criteria. Of all these articles

three were about Hawley’s retainer and vacuum-formed retainer

three were about Hawley’s retainer and fixed lingual retainer

and one was about the different influences of three retainers on periodontal health. The results showed greater periodontal harm in vacuum-formed retainer group than in Hawley’s retainer group at the first month（PLI:MD =0.01

95% CI =-0.38 to 0.40

P =0.970;GI:MD =0.07

95% CI =-0.36 to 0.50

P =0.740） and the third month（PLI:MD=0.23

95% CI=-0.14 to 0.61

P=0.230;GI:MD=0.35

95% CI=-0.02 to 0.72

P=0.060）based on PLI and GI

while no significant difference was observed between two groups at the sixth month（PLI:MD=0.08

95% CI=-0.67 to 0.84

P=0.840;GI:MD =0.16

95% CI =-0.60 to 0.91

P =0.680）. Besides

no significant difference was observed between fixed lingual retainer and Hawley ’s retainer at the first month（PLI:MD =0.06

95% CI =-0. 01 to 0.13

P=0.090;GI:MD=0.52

95% CI=0.24 to 0.80

P=0.000）

3 month（PLI:MD =0.13

95% CI=0.09 to 0.17

P=0.000;GI:MD=0.47

95% CI=0.21 to 0.74

P=0.000）

and 6 month（PLI:MD=0.99

95% CI=-0.05 to 2.03

P=0.060;GI:MD=0.19

95% CI=-0.14 to 0.52

P=0.260）. Conclusion:Fixed lingual retainer has greater tendency to impair periodontal health than Hawley’s retainer

and vacuum-formed retainer poses greater impairment on periodontal health higher than Hawley’s retainer does in short term. Due to limited number of included studies and lack of high-quality studies

high-quality and large-scale samples are still needed to further verify our study results.