 So another session on dentistry and more, so today's topic is with sepracel. So with sepracel is basically it's not perfectly an analysis, it is basically a diagnostic aid to measure the Joe discrepancy on a lateral cephalogram. So with sepracel was put forward by Aleksandar Jacobson and he was working in the university of Witwatersrand. So that is why this name has came with sepracel, it is that university's name that Witwatersrand, he was working in that university that Aleksandar Jacobson. And the basic purpose is to identify instances in which the ANB reading does not accurately reflects the extent of anterior posterior jaw displacer on a sagittal plane. So we have seen this ANB angle that is nasion, point A on the maxilla and point B on the mandible. So this ANB angle is usually 2 degree. So this we have seen in senors analysis but sometimes this reading might be wrong and there are lot of shortcomings in ANB angle because the ANB angle decreases when the anterior facial height is increased. So there is increased anterior facial height, this ANB angle decreases. So to avoid that ANB angle discrepancies in patient to patient Mr. Aleksandar Jacobson put forward this Witsepracel and because ANB angle basically reflects the relationship of jaws of each other and also to the cranial base. So as I said it is a diagnostic aid to measure the jaw discrepancy on a lateral seph. And usually there can also be the ANB angle affected by the rotations and variations of sagittal and vertical jaw dimensions relative to the cranial base. So to avoid this problem Jacobson put forward this Witsepracel and what we are doing in Witsepracel is this is a enlarged portion of the point A, point B and the central incisor the lateral seph enlarged portion. So from point A and point B and we are making a functional occlusion plane this line is functional occlusion plane by maximum intercuspation seen. So this is a functional occlusion plane and we draw a perpendicular line from A to this occlusion plane which is known as AO and a perpendicular line from point B to the occlusion plane which is known as BO. So this is functional occlusion plane a line dropping from point A and a line from point B that is perpendicular line AO and BO. So this is the procedure we are doing in Witsepracel. So basically this class 2 if it is a class 2 relation we know this maxillary proclination will be there the maxillary teeth will be proclined. So the point A will be ahead of point B. So AO will be ahead of point BO in class 2 and this BO will be ahead of point AO in class 3 and most commonly this will coincide in mostly the female cases. So among women it is coinciding AO and BO will coincide. So the functional occlusion plane is the key plane that is a plane where we keep reference for Witsepracel. So how do we apply this Witsepracel? So instead of taking angle we are taking linear measurement. So that is the difference between ANB angle here ANB angle the angulation between A to B compared with the nasium point. So since there is lot of problem with the skeletal parameters so there is lot of discrepancy may happen with the ANB angle. So to avoid that angular measurement we are taking linear measurement especially the dental parameter we are taking the measurement between AO and BO to describe the anterior posterior joharmony because it is not affected by the skeletal parameters. But again measuring this distance to explain the joharmony of our maxilla mantiple it is again under criticism because the problem is this occlusion plane this occlusion plane can be easily affected by tooth eruption and dental development. So there are difficulties or inaccuracies like identification of occlusion plane also will be there and also inclination of occlusion plane may change by the vertical movement of incisors, molasses or both during the treatment. So Witsepracel also is not a perfect method so it can also be affected because of this occlusion plane may change during the tooth eruption and development inaccuracies in identifying this occlusion plane and inclination of occlusion plane due to the growth changes. So that is all about Witsepracel it is an adjacent to ANB angle because the angulation difficulties or the problems associated with angle and its changes we move to another technique of dental parameters that is difference between the occlusion plane that is connecting AO and BO and comparing and associating with the ANB angle. So that is all about Witsepracel it is a linear measurement between the two points AO and BO and providing an additional information regarding the Joe Disarmonie in an anterior post zero line. So I will come up with a new session under industry and more thank you.