OBJECTIVE: this article aims to analyze the expression of TNF-α, RANKL, and osteoclast cells count after application of DDMM as GBR in mandibular bone defects.

METHODOLOGY: this is an experimental study with a post-test only control group design, which began with the randomization of 120 rats into five groups: K(-), without membrane implantation; K(+), PPCM; P1, DDMM; P2, DDMM + bone graft; P3, PPCM + bone graft. The expression of TNF-α, RANKL, and osteoclast cells count were observed, followed by analysis using a one-way ANOVA and post hoc Tukey HSD comparison test.

RESULTS: there were significant differences in the expression of TNF-α, RANKL, and osteoclast cells count in all study groups (p=0.000). TNF-α showed a decreasing difference with the highest expression in the K(-) group on day 3 of 12.00±2.16. RANKL expression increased on day 14 and decreased on day 21 in all groups. The osteoclast cells count generally showed a critical period with the highest increase in the K(-) group on day 14 of 73.00±0.00.