IL-15 Gene Polymorphism Associated With Early Marginal Bone Loss Around Endosseous Dental Implants

ABSTRACT

Objective: Early marginal bone loss around dental implants before stage II surgery occurs occasionally despite lack of obvious cause and etiology of this bone loss is not clear. Genetic polymorphisms that regulate the inflammatory process have been considered a genetic risk factor for early bone loss around implants. Interleukin-15 (IL-15) up-regulates pro-inflammatory cytokines such as TNF-α and IL-6 and enhances immunoglobulin secretion in the presence of oral bacteria lipopolysaccharides. In peri-implant tissues, those pathways may lead to bone resorption. IL-15 has potential role in bone remodeling, and resorption of bone around the hip implants. rs1057972 polymorphisms in the IL-15 gene have been associated with inflammatory and autoimmune diseases. The aim of this study was to investigate whether the IL-15 gene polymorphism is associated with early peri-implant bone loss before stage-II surgery.

Materials and Methods:A total of 194 implants were placed in 74 unrelated patients. The patients were divided into 2 groups: 1) study group: with 1 or more marginal bone loss greater than 0.5 mm; and 2) control group: with marginal bone resorption less than 0.5 mm. After DNA collection and purification, IL-15 polymorphism analysis was performed using TaqMan genotyping assay. Interferences of clinical and local parameters related with early marginal bone loss were also evaluated. Linear regression tests were performed between each of the groups to determine which genotype groups were significantly different from one another.

Results: rs1057972 SNP was within Hardy-Weinberg equilibrium (p>0.05).  The frequency of IL-15 rs1057972 polymorphism was significantly higher among patients in early marginal bone loss (+) group than those in early marginal bone loss (−) group (P < .05). Regarding rs1057972polymorphism, the allele T was associated with early marginal bone loss (p=0.03) around implants. There was no significant difference between other predisposing factors.

Conclusion: These results may suggest a potential role of genetic variation in alleles of rs1057972polymorphism of IL-15 gene in the etiology of early marginal bone loss around implants.

Reference

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