Although varicella zoster virus (VZV) infection commonly occurs in the oral and maxillofacial region, tooth exfoliation and alveolar osteonecrosis are relatively rare complications. We describe two cases of tooth exfoliation and alveolar osteonecrosis caused by VZV infection of the trigeminal nerve and review the literature. A 66-year-old man and a 38-year-old man were referred to our hospital because of tooth exfoliation. The first patient had a history of spinocerebellar degeneration, and the second had a history of chronic myelogenous leukemia. Tooth exfoliation occurred on day 21 and day 25 after the onset of VZV infection, respectively. Clinicopathological examination in the first patient revealed actinomyces infection. Panorama x-ray films obtained previously in the second patient revealed no evidence of severe periodontal disease before VZV infection. These findings suggested that tooth exfoliation and osteonecrosis by VZV infection were not only caused by existing severe dental infectious disease, but also by various factors such as multiple oral bacteria, tissue reaction to VZV infection, and compromised status.