<prompt> Ludwigs angina is -Unstable anginaPrizmetals anginaInfection of submandibular spaceInfection of retropharyngeal space  <response>: Ans. is c i.e., Infection of submandibular space o Caldwell-Luc operation is a process of opening the maxillary antrum through canine fossa by sublabial approach and dealing with the pathology inside the antrum.o In this surgery, antrum is reached through a incision in gingivolabial sulcus from lateral incisor to 2nd molar and then opening of antrum in this area.o During the surgery a noso-antral window is made through the inferior meatus so that after the surgery, packing of sinus can be removed through this window. 