This case report describes a lateral luxation of an upper incisor in a 19-year-old non-professional boxer. The tooth displacement gradually worsened over several months because the boxer received repeated blows to the head without using a mouthguard. Being a chronic dental trauma, rather than an acute lateral luxation, this case had several unique features: the labial plate of the alveolar bone was penetrated, the root apex was free in the vestibulum, the tooth was mobile (second degree) and radiographs revealed bone resorption. This case emphasized the need for a mouthguard to be used even with amateur boxing. The dental practitioner should educate his sportsmen-patients of the risk of sport-related dental trauma and the benefit of a mouthguard.