INTERNAL ANATOMY INBDE NBDE PART 2 NEET INI-CET

yeah happiness back here uh with the next topic that is uh the internal anatomy and the considerations okay so it's one of the important topic and of course i can tell you this is one of the memory based topic in entire subject of endodontics in a few cases you may miss the logics but it is mandatory that you have to learn because they are going to give questions on this particular area so let's start the topic so first of all like uh like how can i compare like something like uh you are if you are adapted to a particular room for example you have your study room and you're very adapted to your room because you are staying in the same room for years so what happens is on one day there is no power okay but you can enter the room because you are well aware of the room because you know which object or which article or which book is there at which place and you can easily close your eyes and you can easily pick the book because you have command on the anatomy of the room so endodontic anatomy is something like that if you don't know you cannot enter because it's something like a blind game until you have an endodontic microscope or until you have a dental operating microscope if you have a dental operating microscope dental operating microscope is going to improve the visualization means it's going to provide you the magnification and it's going to provide you the illumination it's going to provide the light for the dark room whereas regular most of the operated systems like we go for blindfold we don't know what is there but we just dig and we just find something so it's something like that a successful root canal treatment requires a strong command knowledge on the anatomy of the teeth as well as the anatomy of the root canals and their modifications so there are few things which i'm going to discuss basically i'll be focusing more on your questions rather than the concepts so because i'll try to cover the areas where most of your questions will come from so as already discussed okay so when you want to visualize something like when you want to visualize the the tentinal maps which are on the floor of the pulp or if you want to visualize the fractures or crack tooth syndrome i told you to use a dye that is preferably you can use this methyl methyl blue or you can use two percentages of iodine okay followed by you're going to visualize under dental operating microscope or under magnification either by using loops so that you can visualize this dental map clearly and just to make a note of this particular test which is very very important they're going to ask the questions that is called a stamp face bubble test so regularly what is the mechanism of sodium hypochlorite of course we learn it in irrigation solutions the mechanism of sodium hypochlorite is to identify the vital structure is identify the organic structure and dissolve it so while dissolving these organic structures for the leftover vital structure means the vital structure in the root canal is going to be the vital wall we can see this vital pulp so whenever it identifies the vital valve it is going to dissolve so when dissolving it's going to release bubbles that bubble test is called as samford's bubble test the material used is sodium hypochloride and it's going to identify the mist canals where the vital pulp is there the next one of course radiographs reminds the primary and the most important method of identifying the root canal morphology but is it one radiograph no it is a radiograph of multiple directions so there is one question that is given in one of the recent session like what is waltran's radiographic method so walters radiographic method is something very specific to end up okay so you take two radiographs with a difference in horizontal angulation of 10 to 15 degrees so you maintain the same vertical angulation but you you will have a different horizontal angulation so the change in the horizontal angulation is what is the change the change is 10 to 15 degrees so when you change this horizontal angulation by 10 to 15 degrees you can see the overlapped things for example in one situation there may be two canals which are present on the uh the digital root of the mandibular molar may overlap but once you change the angulation they can be seen as two that is the main use of this wall trans radiographic method so make a note always try to take more than two or two radiographs more than two or two radiographs are mandatory and different horizontal angulations maintaining the same vertical angulation same vertical and different horizontal very important the next comes of course uh the latest trend of cbct has lots of importance in dentistry and of course i like most of you are preparing for dds and according to my references and according to my like feedbacks from my seniors and most of us in usa it is mandatory to take a radiograph before you start any root canal treatment and they charge a decent amount for cbcd also but i feel like in india it's very rare to see a cbct before you start an adult treatment in the clinical scenario very very rare in the clinical practice like in the colleges for the academic use of course i have seen i have taken cbct's but uh so that's what the trend is like in usa so it's mandatory that you have to learn so much related to cbcp so cbct is something like it's going to give you three dimensional view it's going to give the anatomy at different levels anatomy everywhere so it is the best modality it's a non-invasive best modality by which you can i mean like uh know the anatomy without damaging the tooth structure right so you can see this is a case where you hack you can see more canals regular anatomy as everyone can do but a tricky or complicated anatomy you you must need aids like cbcd you just need it's like dental operating microscopes to see that with the naked eye because it's all like blind game until now everything is blind again so you need something to visualize it so the best method is going to be the cpcd and of course i already was stressing you from day one that is dental operating microscope maybe not a few dental colleges i mean like dental schools and dental universities which may ask you to do your bench test under magnification either by using the loops or either by using the gentle operating microscope like before you go and attend this bench test make sure you just aware of this okay so because most of you were not well aware of dental operating microscope so you need to work or loops we regularly don't use it okay so i want you guys to make a note of this okay in future it is required to know what is happening around this so i just want to talk about few important aspects here and there which were given in examinations or which are which were the questions uh in your examination so first i am going to talk about the maxillary central regularly your maxillary central incisor is going to have one root and one canalic and you can see the lateral canals in 60 percentage of cases and your maxillary central is most often i mean if you see the canal it is most often triangular in shape very rarely you can see oval so it's better to better to go for a triangle as a as a very very decent and a good option the next comes is the maxillary lateral so maxillary lateral you will have curvatures curvatures are most common in maxillary lateral incisor okay regularly you see one root and one canal and the shape if you come to the shape it is oval in shape you will have curved roots make a note you'll have curved roots and make a note we have already discussed these two points that is your palatal gingival group is most common at this area and your palatal abscesses your palatal abscess are also most common in the maxillary lateral the next comes is the maxillary canal maxillary cannon is also one root and one canal mostly and it is the longest okay your maxillary canine and mandibular cannon are the longest tooth in the in the oral cavities okay and if you see the cross section the cross section is all and make a note your maxillary canine uh is having a digital inclination okay so all your maxillary maxillary lateral maxillary central maxillary canine all these are having a bit distill inclination okay so that's an important thing that you have to make a note so i'll slide away jump to the mandibles okay so coming to the mandibular centrals and laterals mostly it is central and laterals are centrals and laterals are they contains one root but chances of two canals are common right chances of two canals are very common like in 20 to 40 percentage of cases you'll have two canals in the maxillary centrals maxillary central and lateral incisor and the cross section you see is long wall the cross section you see is long oval in this case and coming to the mandibular canine so the few important things that you have to make a note about mandibler cannon one route okay one route you'll have one route and the crown was labial inclined you'll have a labial inclination of the crown so whenever you have a labially inclined crown make sure you you you try to you try to do the axis opening by giving by by giving the proper direction if not you're going to cause the perforation right so it is very very important you just make and what about this labial uh i mean labially inclined okay and the next important aspect is coming to the cross section you see it is large vowel okay so these are the important things that you have to make a note and of course these c-shaped canals are not much familiar in the case of americans so they may not ask you questions but these are most commonly seen in the case of uh asian asian people okay they may ask this question uh uh in the in the in the bench test okay so she shaped canals are most commonly seen in which are the teeth the c-shaped canals are most commonly seen in the case of mandibler second molar mandela second molar you can see these three shaped canals most commonly and these are common in the case of asians okay i hope you have done these important points and coming to this normal uh tooth structure it's divided into kernel root and radicular radicular portion and each component is going to have enamel dentin pulp cementum and pdl which we are going to discuss in detail in dental uh not so the pulp is classified into coronal pulp and the radicular pulp and the coronal pulp of course this is a question again for you guys coronal pulp has how many surfaces coronal pulp has six surfaces what are the six surfaces that is occlusal mesial digital buccal lingual and floor make a note of this next jumping to the pulp horns and of course i hope you know the meaning of pulp horns which which are going into the cusps and the lobes and the application-based question is why permanent crowns are contra indicated in any individuals because pulp horns are highly placed when you're giving crown cutting there are high chances that the pulp horns can be exposed right the next course is the radicular pulp radical pulp is the pulp that extending from the cervical region of the crown towards the epics so this is called as this part is called as the radicular pulp so the radicular pulp at the end is going to communicate with the very epical connective tissue through a foramen called as the apical foramen the next comes you need to make a note of this landmarks that is i mean the most important uh essential landmark to identify the pulp chamber is cemento enamel junction so make a note cemento enamel junction is an important landmark for location for location of pulp chamber and orifices whereas cemento dentinal junction is an important landmark where your root canal preparation should end okay so if you see this dental structure teeth okay so this is your cemento enamel junction whereas whereas this is your cement or dentinal junction so your root canal preparation is going to start at cement enamel junction and at cement or dentinal junction so this is the end where you are going to find the working length so your working length your biomechanical preparation your observation everything should end at cement or dentinal junction they should start at cement enamel junction right so location of pulp chamber cement enamel junction and end of your preparation everything cement antenna junction so these are the few uh i mean last that you have to make a note laughs centricity means your your floor of pulp chamber is always located in the center of the teeth at the level of cement and ammo junction law of concentricity says that the walls of the pulp chamber are always concentric to the external surface okay same as external surface at the level of cement and i will junction law of ch is of course this is a constant and important landmark which helps in the position of the pulp chamber okay the next goes is basing upon the relationship of the pulp chamber and the clinical crown the pulp horns i mean the pulp chamber has some symmetry class the symmetric law is symmetric lava the lava one says that except there is exception except for maxillary molars the orifices of the canals are equidistant means they are if you draw like this they are equidistant in in a particular direction that is the mesodigital direction la 2 says that except for the maxillary molars the orifice of the canal slice a line perpendicular to the line drawn from okay this is a line okay if you draw a perpendicular line they they lie in the same area so if you draw a perpendicular line okay ah across the center of the pulp chamber so this is lava and this is la two of symmetry law of color change has already discussing about the dentinal map so the dark color where you can see something like a map this is called as dentinal map so the color of the pulp chamber is always darker so the dentinal map is always darker than the walls the walls will be bright in color whereas your tentacle map will be dark in color so law of orifice location one the orifice location one last says that most of your canals are located at the junction of the wall and the floor so this is the floor and this is the wall so at the junction of both so at the junction of wall and floor you can see your orifices location 2 says that it is located at the angles angles in the floor involved previously i told it it can be located in the junction junction is this angle is this so if it is not located in the junction it will be located in the angle next rfs location 3 says that okay previously the first one is junction the second one is the angle and the third one says that it is located at the terminals of the root developmental fusion lines okay so root developmental fissure lines are nothing but the same area okay developmental fission lines is a place where you can see the orifices is the law of orifice location three says that so we need to make a note about the canal configurations according to the beans there are four types of canals first one is one one means it starts as a one and ends as a one second one is two one okay it starts as two separate canals and ends at one so it is called as two one the third one is two two start set two one two and set two one two the third one fourth one is start set one and then set two so it is one one two one 2 2 1 2 that is type 1 type 2 type 3 and type 4 so there is slight modification of veins and it is done by vertices in vertices you will have eight types okay that is type one that is one one type two that is two one type three one two one means it starts as one splits into two and ends at one type four which is two two starts at one two and set one two you have this is two two the next comes is type five okay type five is starts at 1 and ends at 2 type 6 it is starts at 2 combine to 1 and end set 2 type 7 is 1 2 1 2 starts at 1 splits into 2 again one and split into two type eight is three three you have one two three you have one two three i hope it's very very clear they're going to ask this configuration questions were being asked so please do make a note of this next comes are the accessory canals so accessory canals are an extra canals right it's it's an extra canals you can see all these my nude extra channels so these are the minute canals uh that are extended horizontally or vertically laterally from the sorry from the from the pulp and peridone okay so these are either horizontal vertical lateral and make a note that 98 percent is of ethical ramifications 93 percentage of lateral ramifications are present in apical one-third so this is an ethical one-third area where you see lots of ramifications that's apical is 98 and lateral is 97 so that is a reason why whenever whenever your root canal system fails we generally go for a back section so apex sector is done by like how many uh how many millimeters it is done by so it is done by three millimeters why because all these epical and lateral ramifications are present in the three millimeters so remove them because these ramifications are the primary reason for the endodontic failure so remove them accessory canals your lateral canals all these ramifications are the causes for the failure of endodontic treatment so remove them so okay if you want to remove where you have to remove so this apical three millimeters is going to contain them so remove it right so basically how this apical uh accessory channels are formed accelerate channels are formed by the entrapment of the periodontal ligament vessels in this root shield helium during the calcification because of which you can see this accessory channels and detection of accessory channels how can you detect an accessory canal so when you're going through the periodontal ligament uh during your radiographic observation if you if you see a periodontal ligament observe the thickness of the periodontal ligament of the periodontal ligament space suddenly you can see a bubble or suddenly you can see some deviation on the lateral wall of the root okay because if you see this is your periodontal ligament so suddenly if you see some morphological change in the periodontal ligament for example this is your root and you see your periodontal ligament like this suddenly you can see some extra thing then you can predict okay there is some chances of occurrence of some axiory or lateral canals all that particular area uh significance is uh they play a very vital role uh in in the exchange of the irritants or irritants or the bacterial components okay because they are going to be the culprits for the endodontic failure and pulp may be in this area may be inflamed or necrotic okay so you need to take certain precautions to remove this and to make this area very clean okay because it's very difficult to access with a normal uh conventional endodontic therapy so you need to go for advanced endodontic therapies where you need to plan and remove these accessory canals so the next course is the fercation canal canal which is seen in the furcation area is called as fercation canals okay so these are most commonly seen in the case of multiple rooted teeth where you'll have bifurcations trifurcation at that particular area you can see this forcation canals isthmus okay i hope you have learned this definition is a two canals okay when they're connected by something which is not visible so is defined as a you can see you can see the diagram as a ribbon shaped inter canal communication or a transverse anastomosis or a corridor between two root canals where you can contain dental pulp and pulp related tissues so that is called as isthmus and you have to take utmost care to dissolve or remove the pulpal tissue or the irritants that are present in this isthmus area also it's very difficult to do this but by using the advanced irrigation solutions or irrigation protocols and the devices you can you can remove the isomers also so we learn about few abnormalities okay this is an abnormality which is seen in the asian population but it is very familiar so they can ask you okay shovel-shaped incisors are seen in the case of anterior teeth okay and the next comes is of course we have discussed this in the class that is this palette of gingerbread surgery i have discussed with you so this is a lateral incisor which is having this palette of gingival growth which is leading to endoperial lesion so how you have a treat you have to open the flap and you have to seal everything over this particular area with gic followed by because you have a heavy bone loss here so it is mandatory that you have to keep a graft bone graft over this particular area and you have to seal it so uh the i mean suturing is done so this is a three months follow-up and this is a six months follow-up you can see uh reduction the radiolucency okay so here compared to here you can reduction the radiolucency and decreasing in the uh probing depth okay so let's let's learn a few important aspect your maxillary and mandibular molars are very very important because i can see many equations on this particular area so we'll be discussing the mandibular molars in detail so coming to the mandibular molar that is the first mandibular molar you can see the outline the outline is uh trapezoidal and outline important point and if you see the canals uh on the mesial side you have two canals uh digital side in the most of the situation you have one canal so these two canals are the mesolingual and mesobuckle once one is going to the lingual side one is going to the buccal side and the distal canal is regularly oval in shape and you have one digital canal which is largest in most of the cases okay uh and if it is the largest one and if it is one it is regularly present in the center but if you suspect a canal which is present in either buccal or lingual direction not in the central then you can assume that there are two channels okay for example if you find it on the buccal side that still cannot then you have to you have to negotiate and try to find on the lingual side also then if you have two canals on the digital side that is that can be seen in 28 percentage of cases these two canals are nothing but distur-lingual and dystrophical so if it is three canals that is mesolingual mesobuccal and distal if it is four canals that is mesolingual mesobuccal disto lingual and disturbance right so this is an important thing that you have to make out and make a note uh your your axis axis opening should be always on the mesial side okay two thirds of your axis opening should be on the mesial side because your pulp chamber the two thirds of the pulp chamber of this teeth will be on the mesial side so your axis opening should begin on the mesial side okay so that is very very important that you have to make a note and the teeth which most frequently uh go for endodontic treatment mostly endodontic treatment is your maxillary molars so your mandibular molars when compared with the maxillary molars okay so morally we do endodontic treatment on the mandibular molecules because mandibular molars are more prone for dental caries because in most of the situations smaller leading to pulpal infection is because of dental care so dental caries is more in the maxillary sorry it's more in the mandibular first molars okay it's more in the mandibular molar so root canal treatments are more in mandibular molars when compared with the maxillary molars and make a note care should be taken because maxillary man this mandibular molars are more prone for lingual perforation so you do more lingual perforations in uh this mandibler molars so you have to take utmost care to avoid that okay so that is an important thing that you have to make you know so this is the difference between the maxillary and the mandibular okay so you can see this is a maxillary molar regularly you will see this is a palatal sorry i mean regular this is a maxillary first molar so this is a palatal one parallel one is the biggest one and the next one is you'll have you'll have miso buckle and you'll have disturbance right so this miso buckle is one is mb1 and one is mb2 so mesobuckles sometimes it will be one and most of the cases it it will be splitted into two that is mesobuccal and one and miso buckle two then this two buckle and this is a parallel and coming to the mandibular as already discussed regularly you will have your mesobuckle okay your mesolingual disturbance and distilling one regularly you may have this configuration two sometimes the two three canals may be splitted into four your maxillary molar will have this combination three if it is four it will be splitted into two that is mb1 and md2 i hope uh you're clear about this so when i'm talking about this i'm already done with the max the max first the mandibular first smaller i'll be talking about the maxillary first molar because most of your questions will move around the maxillary and mandibular molars okay so the first important thing is the triangular outline the outline of the chamber is triangular outline and and if you see this what we have discussed the triangular outline is this is one right this is one right and this is one right this is mb this is disturbance and this is parallel so this this gives a triangular shape right this triangular shape so in this triangular shape the apex is formed by the effects is formed by the palatal okay the apex is formed by the palatal root whereas your base is formed by the these two okay your base is formed by these two and whenever you have the suspection of the fourth canal the fourth canal will be lingual to that of the mesobucca so your mb2 will be lingual to mb1 okay lingual to the mb1 okay the next important thing is uh most common cause for the failure okay teeth with maximum failure rate is the maxillary first molar because you most of us with the naked eye it's very difficult to identify this ambit so that is a reason why so the most complicated root canal anatomy or the most complex root canal anatomy is seen in the case of maxillary first molar and you can see 90 percentage of cases of maxillary first molar will have this mb2 followed by your accessory canals and more than 58 to 60 percentage of cases you can see mb2 so mb2 is seen in more than half of the cases okay and make a note your palatal canal is the largest canal and it is the widest canal it is the good tempered kernel very well good tapered canal you can see a maxillary first molar so apart from this when when you want to place post post there is something called as post and core which we'll be discussing further so when you want to place this post okay for a particular teeth pose should always be placed in the largest canal so for a maxillary first molar the post should be placed in the palatal for mandibular first molar the pose should be placed in the digital okay so these are the important things that you have to make here when i'm talking about the maxillary first molar the next comes is i just want to give a brief idea about this maxillary first premolar few questions on maxillary a few questions on your maxillary first premolar so coming to the maxillary first premolar regularly your maxillary first premolar will have two canals so your maxillary first premolar will have maxillary first premolar will have two canals in most of the cases it will be two canals right so and like in around like 70 percentage of cases it will be two canals in around like 30 percentage of cases it will be uh one canal okay one channel okay so so this is a this is a this is i mean like this is two two that is two two means two uh two configuration two roots and two canals in the case of seventy percentage of cases and one root in case of thirty percentage of cases this is this is regularly and out of these two canals if you see the two canals one is buckle and second one is palatal the parallel canal is the largest and the wider one okay the parallel canal is the largest and the middle one and make a note maxillary first premolar there is one problem on the mesial side that is you can see this mesial concavity which we learn in dental anatomy so this mesial concavity is the most common site of perforation so you have to be at most care when you are treating the maxillary first molar endodontically because there are high chances that you may perforate at this area so when you come to the cervical level of this maxillary first premolar uh the cervical level where you can where you can see an electrical shape electrical shape and few people they call it as a figure of eight they call it as figure of it but make a note the opening the opening axis opening of this maxillary first premolar is the oval shift the next goes is the mandib the next course is the maxillary second premolar so we are done with the first until now so we will be focusing on the second removal so maxillary second premolar uh is almost like the same it has 75 percentage of single root and around like 20 25 percent is of two roots very rarely you can see the other modifications in this but make a note the difference between the max first and mandible first is mandible second mandibular second premolar is mandibular second premolar has high incidence of axillary canals accessory canals around 60 percentage of cases you can see these accessory cameras and making it all the maxillary teeth are are in very close approximation to that of the maxillary sinus sinusitis so you have to take utmost care regarding the maxillary sinusitis okay when you're treating this uh maxillary tree that is the maxillary first second premolars maxillary first and second molars okay so this is all about uh your maxillary second premolar the next comes that we need to make a note about the mandibler premolars so the most commonly asked question about mandibular premolars if you if you consider these two i'm not good at diagrams if you consider these two as a mandibular premolars so make a note there is some landmark that is present between the two premolars that landmark is called as a mental foramen so you have to use slob rule to rule out so whenever you are planning an endodontic treatment in relation to these teeth and sometimes what happen like if you if you do slop from this side what happens is the same the same iop i can look like this look like this so this is an overlapping this is actually not a periapical lesion this is in a mental format sometimes it can be periapical lesion also so what you have to do is like you have to apply the slob rule so that by changing the angulation the mental foramen changes the mental foramen changes if it is moving away then it is mental foramen if it is like in the similar way something like this after changing the angulation if it is something like this so then you can consider it's a periapical lesion so it is very important consideration you can apply your wall trans technique over here or you can apply your slop technique over here to identify whether it is a mental foramen or whether it periapical lesion and second most important thing as you have a bundle of nerves which are going in between these teeth okay regularly your periapical endodontic surgeries so something like we have an endodontic surgery topic also these surgeries are contraindicated in this particular area because you have a vital structure that is a mental foramen containing the mental nerves is there so the endodontic surgeries are contraindicated in this particular case and uh the next important thing that you have to make a note is uh your mandible or first and second premolars so the difference between the first and second premolars uh when coming to the anatomies the first premolar will contain two canals two canals which may end with two orifices or which may end with one orifice okay so uh this is around like 27 percentage of cases and the second one is mostly it will be one and one that is one channel and one one foramen and it will be around like 80 to 85 percentage of cases so that is the law basic difference that you have to make you know when you're talking about the first and the second premolars okay so i think this is more than sufficient so last but not the least is you can see this typical morphologies which are nowadays the most commonly asked question that is one is intermolaris and second one is paramolaris so what is intermolaris intermolaris is an additional distrolingual root okay both are seen in the mandibular molars okay so if it is an additional disto lingual root then it is called as entomolaris if it is an additional root dystrophical root then it is called as para molaris okay so make a note ento is disto lingual root and para is dystopical right so please do make a note of these two differences because again these two are commonly asked questions if you see the recent sessions of your uh in video as well as nbd part two there were lots of questions moving around this in many many official groups okay done for now signing off dr srikanth from team imbd conquer let's enjoy this learning phase which not only gives you uh the tagline of pass in the examination but gives you lots of knowledge and interest towards dentistry or a particular field in dentistry