Toll-like receptor (TLR) and matrix metalloproteinase (MMP) polymorphisms and periodontitis susceptibility: a meta-analysis

The aim of this study was to determine whether the toll-like receptor (TLR) and matrix metalloproteinase (MMP) polymorphisms confers susceptibility to periodontitis in ethnically different populations. A literature search using PubMed and Embase provided the data to conduct a meta-analysis on the associations between the TLR2 Arg753Gln, TLR4 Asp299Gly, Thr399Ile, MMP-1 -1607 G1/G2 and MMP-9 -1562 C/T polymorphisms and periodontitis. A total of 32 studies (14 on TLR polymorphisms and 18 on MMP polymorphisms) were considered in the meta-analysis. The meta-analysis showed no association between periodontitis and the TLR2 753Arg allele (Odds ratio [OR] = 0.962, 95 % confidence interval [CI] = 0.662-1.400, p = 0.841). Meta-analysis of the TLR4 Asp299Gly and Thr399Ile polymorphisms showed no association between periodontitis and the TLR4 299Asp allele in all study subjects (OR = 0.984, 95 % CI = 0.761-1.271, p = 0.900; OR = 1.030, 95 % CI = 0.748-1.418, p = 0.854). Meta-analysis showed an association between the MMP-1 -1607 G2G2 genotype and periodontitis in Asians (OR = 3.778, 95 % CI = 1.210-11.80, p = 0.022). Meta-analysis containing only studies in Hardy-Weinberg equilibrium revealed no association between chronic periodontitis and the MMP-9 -1562TT genotype (OR = 0.638, 95 % CI = 0.265-1.533, p = 0.315). This meta-analysis demonstrates a lack of association between the TLR2 Arg753Gln, TLR4 Asp299Gly, Thr399Ile, MMP-9 -1562 C/T polymorphisms and periodontitis, but shows an association between the MMP-1 -1607 G2G2 genotype and periodontitis in Asians.