BACKGROUND: To investigate the risk factors for plate exposure in primary oral cancer patients with mandibular defects undergoing tumor ablation followed by vascularized free fibular flap (FFF) transfer, we conducted a retrospective observational study in a single institution in Taiwan. METHODS: Between 2015 and 2019, a total of 292 primary oral cancer patients who underwent FFF reconstruction was performed. A variety of clinicopathological, surgical together with post-operative parameters were identified and assessed. The data was statistically analyzed with univariate and multivariate logistic regression and the probability of plate exposure-free rate was plotted as Kaplan-Meier survival curve. RESULTS: The overall plate exposure rate was 28.76 %. The re-exploration group had a higher rate of plate exposure than patients without re-exploration (12.2% vs. 5%, p <
0.05). The 3-year probability of plate exposure-free rate in patients with (n =216) and without (n =76) post-operative radiotherapy were 65.9% and 92.5%, and in patients with (n =141) and without (n= 151) post-operative wound infection were 55.3% and 91.2%, respectively. The multivariate logistic regression showed post-operative radiotherapy and wound infection were independent risk factors for developing plate exposure (adjusted odds ratio [95% CI]: 3.73 [1.37-10.68] and 10.71 [5.15-22.26], p = 0.01 and p <
0.001, respectively). More patients required surgical intervention to manage the exposure of hardware.