 Today we have an orthodontic topic that is maxillary expansion, so how do we expand maxilla. So we have two methods, one is slow and one is rapid. So two ways we can do the expansion of maxilla. So let's see what are the basic differences between slow maxilla expansion and rapid maxilla expansion. So we have nine parameters here. So let's see how it differs in these parameters, the first one is type of expansion. So in slow expansion is both skeletal and dental is happening from the beginning that is in one is to one ratio but whereas in rapid maxillary expansion it is mostly skeletal that is at the beginning period and later dental is coming. So it is like eight is to two ratio that is mostly skeletal expansion is happening and the next one is rate of expansion as the name suggests the rate of expansion is slow here and it is very rapid here and the tissue retraction. Since it is a slow expansion the tissue retraction is more of physiologic in nature but it is traumatic to the tissue since we are applying very rapid process a greater amount of force. So coming to the foos used it is a milder force in slow expansion that is two to four LBS and it is greater compared to slow and rapid expansion that is 10 to 20 LBS. So the frequency of activation is low and less frequent in slow expansion that is 0.5 to 1 mm per week but in rapid expansion it is 0.2, 0.5 to 1 mm per day. This is per week and this is per day and duration of treatment this since it is a slow expansion it takes longer duration as it is rapid it will be completed at a shorter span and type of appliance is used in slow expansion mostly both can be used that is fixed and removal appliances can be used but in rapid expansion it is mostly fixed appliance. So the age group where we can do this expansion the slow expansion can be applied to any age group but rapid expansion should be focused the age group where the mid palatine suture is not fused so it should be applied before the fusion of mid palatal suture and regarding the retention there is less chance of relapse in slow expansion but has more chance of relapse in rapid expansion. So let us see few examples for slow expansion devices that is quad helix and w spring and in rapid expansion devices we have both tooth and tissue bone and tooth bone in tooth and tissue bone we have the rich wheeler and hash type appliances and tooth bone we have isaxon and hyrax appliances. So that is the basic difference between maxilla maxilla expansion slow and rapid the name itself gives many clues the force applied the frequency of activation is very much related to the rapid expansion and the frequency of interval is more in rapid and the problem is this is more traumatic the tissues but the advantages this will be completed very first. So that is all about maxilla expansion slow and rapid. So I will come up with a new session on the intestine mode thank you.