 Hello everyone, in this video and the video is to be followed, we shall be discussing some of the frequently asked OMFS short-knought questions in university exams. The first short-knought question is winter's lines. Winter's lines are three imaginary lines drawn on the radio tap and specifically intra-oral periapical radio tap. These lines determine the position and depth of an impacted third molar. This method was first described by George Winter. So these lines are described as white amber and red lines. The first line or the white line is drawn along the occlusion surface of the erected mandibular molars and extended posteriorly over the third molar region. So from this white line, the axial intonation or position of impacted tooth can be assessed. The white line also provides an indication regarding the depth at which the tooth is lying in the mandibular when compared to the erected second molar. So basically it indicates the difference in occlusion levels of the first, second and third molars. The second imaginary line or the amber line, which is drawn from the surface of the bone lying beside to the third molar to the crest of the interdental septum between the first and the second molar. The amber line indicates the margin of the angular bone enclosing the tooth. Hence when soft tissues are reflected, only that portion of the tooth shown on the film to be lying above and in front of the amber line will be missing. While the rest of the tooth will be enclosed within the angular bone. So basically it represents the height of the bone level in which the third molar is encased. The red line is an imaginary line drawn perpendicular from the amber line to an imaginary point of application of an elevator. Usually this point is the cemento enamel junction on the mesial aspect of the impacted tooth. Unless it is distoangular impacted tooth, where the application point is the distal cemento enamel junction. The red line indicates the amount of bone that will have to be removed before elevation of the tooth. That is the depth of the tooth in the jaw and the difficulty encountered in removing that particular tooth can be assessed using red line. With each increase in the length of the red line by one mm, the impacted tooth becomes three times more difficult to remove. This is opined by hope. If the red line is less than five millimeter, then the tooth can be removed under local anesthesia. Anything above five mm, the tooth needs to be removed under general anesthesia or local anesthesia sedation would be more appropriate. That's all for this video. The rest of the questions will be continued in the subsequent videos. Thank you.