RESUMEN
This study evaluated the frequency of the tumor necrosis factor-alpha (TNF-α) -308 G/A polymorphism in Brazilians with periodontal health (PH = 51), chronic periodontitis (CP = 74) and generalized aggressive periodontitis (GAgP = 38). Human DNA was obtained from mouthwash samples and TNF-α genotyping was performed by PCR and RFLP analyses. Differences in clinical and genetic parameters among groups were sought by Kruskal-Wallis, χ² and Fisher's exact tests. The allele -308G was detected in 91.7 percent, whereas the allele -308A was found in 35.4 percent of all subjects. No significant differences were observed in the frequency of these alleles (χ² = 2.610, p > 0.05) and the genotypes G/G, G/A, and A/A (χ² = 2.547, p = 0.636) among groups. The data suggest that the TNF-α -308 G/A polymorphism is not associated with periodontitis in this Brazilian population.