The search did not reveal any information about Marina Krauss missing a tooth. The results mainly relate to Marina Krauss as a climbing partner of Laura Dahlmeier and the tragic accident involving Dahlmeier, but no details were found explaining why Marina Krauss might be missing a tooth. If you want, the missing tooth could be due to common reasons such as an accident, dental issues, or other personal medical reasons, but there is no publicly available information specifically addressing why Marina Krauss is missing a tooth. If you want a more reliable answer, please specify if this is about a public incident, a fictional character, or a real person.