Objective To examine the distribution of I1,1 genotypes among the people with Han nationality of different peri- odontal health status and to evaluate if there is an association between the genotype of II,1 and the severity of periodontitis. Meth- ods 271 subjects of Han nationality were selected, among them there~182~of chronic periodontitis and 89 subjects of periodontal healthy control. Full periodontal examinations~taken including full-mouth clinical attachment loss measurements, probing depths and bleeding on probing. DNA samples~obtained with buccal swabbing technique and were further analyzed for ILG1 genotype polymorphisms using PCR-RFLP-based method. Results The results showed a significant increase in the frequency of IL, 1 A-889/Nco I allele 2 , II.1 B+3953/Taq I allele 2, IIr1B-511/Ava I allele 2, IL, 1A-889 plus Ur1B-511 allele 2 and II, 1 B + 3953 plus IL- 1 B-511 allele 2 in patients with severe chronic periodontitis as compared with periodontally healthy controls. Conclusion Findings from this study bring into question the usefulness of the genotypes of allele 2 of II-IA-889, IL-IB-511 and IL- 1B+ 3953 as a method for determining the susceptibility of Chinese patients to chronic periodontitis. There is a possible rule of IIrlgene polymorphisms in the susceptibility to chronic periodontitis for some patients.
