Evaluation of the relationship between interleukin-1 gene cluster polymorphisms and early implant failure in non-smoking patients

Objective: The aim of the present study was to investigate the relationship between specific polymorphisms of the interleukin-1 gene cluster and the early failure of osseointegrated implants. Material and methods: The subject population was composed by a test group comprising 28 non-smoking patients (mean age 52.7) that had suffered one or more early implant failures and by a control group consisting of 34 individuals (mean age 43.3) with one or more healthy implants. Genomic DNA from buccal mucosa was amplified by the polymerase chain reaction (PCR), followed by restriction fragment length polymorphism (RFLP) and submitted to polyacrylamide gel electrophoresis to distinguish the alleles of the interleukin-1A (-889), interleukin-1B (+3953), interleukin-1B (-511) and interleukin-RN (intron 2) gene polymorphisms. Differences in the allele and genotype frequencies between control and test groups were assessed by chi(2) test or by Monte Carlo simulations (P < 0.05). Haplotype frequencies, linkage disequilibrium and Hardy-Weinberg equilibrium were also estimated. Results: No statistically significant differences were found in the genotype distribution or allelic frequencies of the polymorphisms. No differences were observed between control and test groups when different interleukin-1 gene cluster haplotypes were compared. Nevertheless, the interleukin-1A (-889) and interleukin-1B (+3953) polymorphic sites were in strong linkage disequilibrium (P=0.00014 for control group and P=0.0238 for the test group). Conclusion: This study suggests that polymorphisms in the interleukin-1 gene cluster are not associated with early implant failure in a non-smoking Brazilian population.