Most of complications after impacted mandibular third molar (iLM3) extraction surgeries are transient and resolved spontaneously within one or two weeks, but some of them are more complicated and required further treatments to alleviate the symptoms. The aim of study is to revisit incidence and predictors of complications after iLM3 surgery by reviewing previous literature and investigating a population-based data. From Taiwan National Health Insurance Research Database, records of 16,609 patients who had received iLM3 extraction under ambulatory settings were retrieved for analysis. Outcomes of interest included dry socket (DS), prolonged temporomandibular joint symptoms (TMD), and surgical site infection (SSI), which necessitated additional appointments to manage. Odds ratios of having those complications between different variables were analyzed. The incidence rates of DS, TMD, and SSI were 3.6%, 0.41%, 0.17%, respectively; while they ranged from 0.33-19.14% (DS), 0-4.17% (TMD), and 0.2-5.17% (SSI) in previous studies. Logistic regression revealed DS significantly correlated with complexity of odontectomy (2.5-fold of risk) and history of gingivitis or pericoronitis (1.3-fold of risk). More TMD was found in female than male patients (0.5% versus 0.3%). However, no factors associated with SSI was found; neither did we find aging as a risk in association with any of above complications. Compared to previous studies, our data supports that surgical intervention should be considered in iLM3 with risk of gingivitis or pericoronitis to reduce the occurrence of DS. The original information in this article, which provides a "real-world" evidence, along with the organizing data we summarized from previous article, can serve as a reference for clinicians in assessing the complication risks before treatment of iLM3.