TNF and periodontitis: At gingival level, differences were still present after two weeks, among rats without periodontitis (49.57 ± 4.50 vs. 26.05 ± 2.52 pg/mL for IL-1β, p < 0.01; and 34.39 ± 3.19 vs. 18.44 ± 1.87 pg/mL for TNF-α, p < 0.05), although the correlation with PTH levels presented 2-weeks before, was found just in non-injected rats (r = 0.93, p < 0.001 for IL-1β; and r = 0.79, p < 0.01 for TNF-α).