Background: IL-1 is the main regulator of inflammatory reactions. This cytokine also plays an important role in bone tissue remodeling processes. The IL-1α-coding gene and the IL-1β-coding gene are located on the long arm of chromosome 2. These genes contain polymorphic sites. Polymorphic modifications in IL-1-coding genes determine the level of IL-1 release, which can affect bone tissue regeneration.
Objectives: The objective of the present study was to assess the correlation between IL-1B-511 genetic polymorphism and the regeneration of the alveolar ridge bone.
Material and methods: The study was carried out at the Department of Oral Surgery in Bytom, Poland, which is part of the Silesian Medical University of Katowice. The study population comprised 92 patients with mandibular or maxillary alveolar bone defects which had developed following the surgical removal of tooth roots or the enucleation of impacted teeth or cysts. Genetic material was obtained from the epithelial cells of the inner buccal surface. The IL-1B-511 genotype was determined in each patient by means of the phenol-chloroform technique, in order to enable DNA isolation, as well as by the PCR-RFLP method. Once this had been achieved the patients could be classified into 3 groups according to the following genotypes: IL-1B-511 1/1, IL-1B-511 1/2 and IL-1B-511 2/2. Bone regeneration was assessed radiographically using Digora 2.5 software. A comparison was made over a 6-month follow-up period of post-operative bone loss regeneration observed in patients with different types of the IL-1B-511 gene (alleles 1/1, 1/2, 2/2).
Results: A careful analysis of the X-ray images showed that the average increase in the optical density of post-operative bone defects was statistically lower in patients with the IL-1B-511 2/2 genotype than in those possessing the IL-1B-511 1/1 or IL-1B-511 1/2 genotypes. The results indicate that alveolar bone regeneration proceeds more slowly in patients with the IL-1B-511 2/2 genotype compared to those with alleles 1/1 and 1/2.