While extracting a maxillary third molar, it is noted that one of the root is missing, the root tip is most likely to be in the:

The location of root tip will depend on the position of 3rd molar. For Mandibular 3rd molar, if the tooth is vertically positioned, the root tip is most likely in the submandibular space. If the tooth is in mesioangular or horizontal position, it will be located in pterygomandibular space. Maxillary third molar is usually pushed into the infratemporal space.