To assess the volumetric bone changes in double barrel vascularized fibular flap used for mandibular reconstruction using 3D miniplate versus 3D titanium mesh tray. Twenty patients seeking mandibular reconstruction were selected for this 2-arm parallel randomized clinical trial with a 1:1 allocation ratio. Both groups underwent double-barrel fibula free flap for mandibular reconstruction with fixation of the superior barrel to the inferior barrel using a Titanium mesh (Group A) or a 3D plate (Group B). The primary outcome was volumetric bone changes (immediate to 6 months postoperatively). Eleven participants (55%) were females, and 9 participants (45%) were males. The mean age of patients in group A was (28.8±8.9) years, while group B was (30.7±11.4) years. There was a statistically significant difference within each group in the volumetric bone changes with means of -7942.1±1804.8mm3 and -6288.8±2607.3 for groups A and B, respectively. The difference between both groups was statistically insignificant with the mean of -1653.3±1002.8mm3. The percentage of mean volumetric change relative to immediate postoperatively for group A was -14.15%, while in group B was -11.01%. Both the titanium mesh tray and the 3D plate were effective in the fixation of the superior barrel of the vascularized fibular flap for mandibular reconstruction. There was no difference between both modalities regarding volumetric bone changes.