Analysis of the transforming growth factor-beta 1 gene promoter polymorphisms in early osseointegrated implant failure.

Transforming growth factor-beta 1 is a multifunctional cytokine involved in extracellular matrix deposition, reduction of inflammation, and promotion of wound healing. Single nucleotide polymorphisms in the promoter region of human transforming growth factor-beta 1 gene, C-509T and G-800A, have been shown to increase the transcriptional activity of this cytokine and have been associated with a variety of diseases. The objective of this study was to investigate the possible association between these single nucleotide polymorphisms and the early implant failure. A sample of 68 nonsmoking patients was divided into two groups: a test group comprising 28 patients with one or more early failed implants and a control group consisting of 40 individuals with one or more healthy implants. Genomic DNA from oral mucosa was amplified by polymerase chain reaction and analyzed by restriction fragment length polymorphism. The significance of the differences in observed frequencies of single nucleotide polymorphisms was assessed using the chi square test and Fisher's exact test. The cited single nucleotide polymorphisms in transforming growth factor-beta 1 were analyzed in combination as haplotype using the computer program ARLEQUIN. The authors did not observe significant differences in the allele and genotypes to both single nucleotide polymorphisms of transforming growth factor-beta 1 gene (C-509T and G-800A) between control and early implant failure groups. The distribution of the haplotypes arranged as allele and genotypes were similar between control and test groups. These results indicate that C-509T and G-800A polymorphisms in the transforming growth factor-beta 1 gene are not associated separately or in haplotype combinations with early implant failure, suggesting that the presence of those single nucleotide polymorphisms alone do not constitute a genetic risk factor for early implant failure in the Brazilian population.