 Hello everyone, welcome back to another session in the industry and more. So today's topic in prosthodontics is Kennedy's classification of idangelo space and apple gates rule. So it's a very common question and it's a simple one. There are many classifications put forward to classify the idangelo space but the most accepted one is Kennedy's classification. He proposed his classification in 1923. So it gives a positional picture of the teeth present but little information of the exact number of teeth absent or present. He basically pointed out the idangelo space numbers not the number of teeth absent or present. So moving on the class 1. So he classified into 4, 1, 2, 3 and 4. So the Kennedy's classification 1 from the picture itself it's very clear. The missing teeth on bilateral side that is the most posterior areas are missing. So it is the missing sum or all of the teeth on both sides in a single latch and there are no teeth posterior to the idangelo area. So this is the most posterior area. There is no teeth posterior to this area. That is class 1 and class 2 it is a unilateral idangelo area that is only one side the teeth are absent and there is no teeth posterior to this. So it is also known as unilateral distal extension. In the class 3 it is unilateral idangelo area with natural teeth anterior and posterior to it. So it is also known as tooth bone because it is supported by the remaining natural teeth only. And the class 4 it is a single but bilateral which is crossing the midline and this idangelo area anterior to the remaining natural teeth. So the remaining natural teeth are at the posterior side. So the anterior bilateral area which is crossing the midline which is also known as anterior extension and there is no modification for this. So the modification is nothing but the number of idangelo space present. So class 1 will take the class 1 and there is missing tooth like this. So here the two teeth are missing here one teeth are missing. So one, two irrespective of the number of teeth. So Kennedy was highlighting only the idangelo space not the numbers of teeth. So one space and two space. So this is class 1 modification 2. If it was just like this it is missing only at this point only this tooth is missing it will become class 1 modification 1. Even if it is missing like this or missing like this it will be still class 1 modification number 1 because it is not the number of teeth it is the number of spaces that matters. So that is class 1, class 2, class 3 and class 4 and the modification it is the number of idangelo space. So again in class 2 also modification will be there. If it is like this it will be class 2 modification 1. If it is like this class 2 modification 2, class 2 modification 3. So it depends on the number of idangelo space. But there is no modification in class 4. Now let us move on to Applegate's rule. So Applegate's rule there are 8 rules are there. So it is to understand the Kennedy's classification better and also to avoid the confusion. The first rule is classification should follow rather than precede extraction that might alter the original classification. Means always we should do the extraction prior to the classification because if you are seeing a person's upper arch like this this is class 3 idangelo space. So and we are planning the treatment according to this classification and after a period of time we are finding out that the bone support is lesser for this remaining one tooth and we are going to extract this also. Now this becomes class 2. But our treatment was initially based on the class 3. So in order to avoid the confusion in treatment plan also classification we should first do the extraction then cover for classification. That is why the saying the classification should follow rather than precede extraction that might alter the original classification that is rule number 1. Now rule number 2 if third molar is missing and not to be replaced it is not considered in the classification. Suppose we have third molars the central lateral canine premolars and third molars. If this third molar is missing and we are not planning to replace it it is not considered in the classification. Here is the second rule the third rule if the third molar is present and is to be used an abutment it is considered in the classification. In case if you are planning to use this as abutment we need to consider it in the classification. And the rule number 4 so 3 is the third molar is present 2 is if it is not present. The fourth rule is if the second molar is missing and is not to be replaced it is not considered in the classification. So the second molar is missing and we are not planning to replace it it is not considered in the classification. And rule number 5 rule number 5 is the most posterior idensilus area or areas always determine the classification. So the most posterior area. So if you have a posterior idensilus area here so this is one area and we have one area here and we have one more idensilus area here. So we need to consider only this one. So this will be class 2, Kennedy's class 2 with modification number 2. So this is Kennedy's class 2, class 2 modification 2. We are not considering this idensilus area or this idensilus area we are considering the most posterior idensilus area and the remaining idensilus areas will be the modification. And the sixth one is the idensilus area other than the most posterior one which determine the classification are referred as modifications which we already talked about. The most posterior one is considered for the Kennedy's classification and the remaining idensilus areas considered as modification that is the rule number 6. And rule number 7 the extent of modification is not considered only the number of idensilus areas are considered that is if we have a missing tooth suppose if we have a missing tooth 1, 2, 3, 4 that is not considered it is just considered as one idensilus space. Here only one tooth is missing again it is considered as idensilus space just one idensilus space here four teeth missing again the second idensilus space not the number of teeth ok it is a space just a space is considered as one not the number of teeth that is a rule number 7 and the rule number 8 the last rule is there can be no modification in class 4 because any additional idensilus space will definitely be posterior to it and will determine the classification. Suppose let us take if we have a modification if we have a idensilus space here so what will happen so this will be class 3, class 3 Kennedy's class 3 modification 1. So we cannot have any modification in class 4 because if there is a modification if there is idensilus space it will become class 3 modification 1 or modification 2. So there will not be any modification possible in class 4. So that is the apple gates rule 8 rules so I will recap once again the first one is classification should follow rather than precede extraction that might alter the original classification rule number 2 if the third molar is missing and not to be replaced does not considered rule number 3 if the third molar is present and is considered and is keeping it as an abutment it is considered rule number 4 if the second molar is missing and it is not to be replaced it is not considered in classification rule number 5 the most posterior idensilus area is considered or determine the classification and idensilus area that is rule number 6 idensilus area other than the posterior will be considered as a modification and the seventh one only the extent of modification is extent of modification is not considered only the number of idensilus areas that is the number of missing teeth in the modification space is not considered only the number of idensilus spaces are considered and the rule number 8 the last one is there is no modification possible for class 4 and apple gate has a modification in 1960 okay so apple gate modified the classification on the condition of abutment to include two or more additional groups that is class 5 class 5 it is a modification that is a change in the class 3 that is which is idensilus area bounded anteriorly and posteriorly by the natural teeth so this is almost like class 3 but what is the change in which the anterior abutment is not suitable for support so this is the anterior abutment abutment is the supporting tooth okay where we attach our class for any apparatus attaching apparatus so the anterior abutment is not suitable for support so it is basically a class 3 where the anterior abutment cannot be used as an abutment so this is apple gates 1960 modification which is known as the class 5 and one more we have that is class 6 the class 6 is nothing but idensilus area in which the teeth adjacent to the space are capable of so again the class 3 one where the teeth adjacent that is abutment teeth are capable of total support of the required processes so we can take support only from this adjacent tooth because this teeth are very capable we don't need any tissue support mostly this denture like rpds are mostly tooth and tissue supported it will take support from both the tooth and also the tissue but this case the classics where the processes can take the support from the tooth itself or we can say the tooth can give the support for the entire processes in such case we can call it as the class 6 so this is a separate group that is apple gates modified in 1960 so we can say we have six classification basically one two three four and five and six five and six are again a little change in class three five is where the anterior abutment is not suitable classics where the abutments are enough to give the total support that is tissue support is not required the tooth itself can give support and we have eight apple gates rule so that's all about canadi's classification and apple gates rule so i'll come up with a new topic in process on next thank you