[Music] this video is sponsored by bootcamp.com check it out for iron bde prep and use coupon code mental dental for 10 off hey everyone dr ryan here and welcome to my dental anatomy video series this series is going to be all about the structure and function of teeth so adults usually have 32 permanent teeth but some people have more and some have less the complete set of adult teeth is called the permanent dentition distributed between an upper arch and a lower arch the anterior teeth are the front six teeth in both arches the posterior teeth are all the teeth behind those anterior teeth again in both arches incisors are the front four teeth and therefore in sizing or cutting food the upper incisors are arguably the most important teeth for smile aesthetics and they also serve a function in phonetics producing f and v sounds when they touch the lower lip canines are getting closer to the corners of the mouth and sometimes they're referred to as eye teeth because if you drew a line straight down from the eyes they would be pretty close to that line they're longer and pointed for tearing food the molars are for chewing milling and grinding food and the premolars also contribute to chewing as well but to a lesser extent because they're smaller but they can definitely hold food as it's being chewed topics like tooth numbering and eruption dates are things covered in my basic dentistry video so i'm not going to go over them here but i do want to go over conventions for tooth naming really quick when we talk about a specific tooth in the series we're going to start with which arch it belongs to maxillary upper or mandibular lower then we'll say if it's on the right or left side and finally what kind of tooth it is so for example we would say for tooth number eight that's the maxillary right central incisor as part of this series i'll go through each kind of tooth with you and look at the key landmarks and high-yield features of each one from its different views or aspects we'll take a look at the facial view or the facial aspect also called the labial aspect for anterior teeth or the buccal aspect for posterior teeth we'll also look at the lingual aspect which is also called palatal for maxillary teeth since that surface is adjacent to the hard palate we'll look at the mesial and distal aspects we'll look at the biting surface referred to as the incisal surface for anterior teeth or occlusal surface for posterior teeth and lastly some teeth i'll show you a cross section of the crown or root and i'll refer to those views as internal because they're inside the tooth all right next let's review some common terms that we'll refer to throughout this series so a cusp is a pointed or rounded elevation or mound on the crown of a tooth a tubercle is a small elevation on a tooth due to extra formation of enamel so it's a deviation from normal a lobe refers to a center of calcification from which a tooth develops basically the separate divisions that come together to form a tooth often in molars the lobes will become individual cusps most teeth develop from four lobes but we'll go over this more in detail with each specific tooth mamelons refer to small bumps that appear on the incisal edges of teeth when they first erupt and they usually wear away over time due to normal contact with opposing teeth if they remain beyond the age of 10 on those incisors then that might be a sign of an anterior open bite where the front teeth just aren't touching imprecation lines are tiny little ridges or wrinkles that run horizontally or mesio-distally on the cervical third that means towards the gums of the labial surface of anterior teeth the reason why they appear is due to the incremental enamel deposition as the crown is forming perichymata refer to tiny grooves in between those imprecation lines and i'll show you examples of what this looks like in the next video when we talk about the maxillary central incisor the height of contour is the widest part of a tooth essentially the part of a certain tooth surface that sticks out the most on the facial aspect or the lingual aspect etc and i'll show you examples of that as well in future videos the proximal contact is the area of a tooth in contact with an adjacent tooth in the same arch and the last term on this slide is embrasure so whereas a diastema is a space or a gap between two teeth an embrasure is the space around teeth so these v-shaped valleys that you see between teeth are called embrasures and they allow for the passage of food around teeth so that food isn't as likely to be stuck in between them alright so some more terms a groove is a linear depression in a tooth and they come in different shapes and sizes developmental grooves are the biggest ones and they're formed by the uniting of lobes during development of the crown of a tooth so for example on tooth number 12 here there's a central groove that you can see that's between the three facial lobes and the lingual lobe there are also smaller shallow grooves called supplemental grooves that give the occlusal surface a more wrinkly appearance a fossa is a shallow rounded or angular depression usually at the coalescence of multiple grooves so for example this premolar has two triangularly shaped fossa here a fissure is a deeper than normal groove where there was an imperfect union between those developmental lobes i would definitely call this a fissure right here on tooth number 15 a deeper than normal groove a pit is a place where grooves or fissures come together to create a small pinpoint depression this is where decay is most often to begin and that's why sealants are often placed in the pits and fissures to prevent decay in those areas that are most susceptible to decay and hardest for the patient to clean tooth number 13 here for example has a mesial and a distal pit a ridge is basically the opposite of a groove it's a linear elevation of enamel on a tooth crown and they also come in different shapes and sizes marginal ridges are elevated areas that form the mesial and distal borders of teeth triangular ridges descend from a cusp tip and widen as they run down toward the middle of an occlusal surface and last term on this slide is cingulum which is a convex protuberance on the lingual surface of anterior teeth right next to the gingiva and we'll take a closer look at this u-shaped ridge when again we talk about the maxillary central incisor in the next video of this series and i have five more terms for you that are less to do with the crown of a tooth and more to do with its root so an apex is the very end or tip of a tooth root and the apical foramen is an opening at the end of a tooth root where nerves and blood vessels enter and exit through next term is furcation and just like how a tree branch splits into two some teeth have multiple roots and that branching point or dividing point of a multi-rooted tooth is called the furcation it's called a bifurcation if it branches into two roots in a triforcation if it branches into three roots the cemento enamel junction or cej for short is where the cementum and enamel layers meet on a tooth's surface it's also called the cervical line since it forms a line on the neck of the tooth the part of the tooth right by the gums and lastly we have the root trunk that's the area of a root between the cej and the frication finally let's apply some of the terms we just learned and give you some overarching trends and general features that apply to the entire permanent dentition as far as teeth most likely to be missing third molars are most common then mandibular second premolars and finally maxillary laterals i know there's a lot of discourse around which of these two is most likely missing after the wisdom teeth but this is the trend i have settled on being most accurate for patients in the united states so that is what i recommend you study and memorize for the board exam as far as tallest crowns first is mandibular canines then maxillary centrals and finally maxillary canines this one's interesting all teeth are wider facial lingually than mesio-distally except maxillary incisors and mandibular molars which are wider mesio-distally all teeth have a facial height of contour in the cervical third except mandibular molars which have their height of contour in the middle third all teeth have their lingual height of contour in the cervical third if it's an anterior tooth or middle third if it's a posterior tooth except for those pesky mandibular second premolars which have their lingual height of contour in the occlusal third generally as you go distally and more posteriorly the crown heights of teeth decrease and for molars the lengths of root trunks increase lingual embrasures are almost always larger than their facial counterparts and that's to encourage the pushing of food towards the tongue alright so with all of that background we're now ready to dive in tooth by tooth so stay tuned for the next videos in this series it for this video thank you so much for watching please like this video if you enjoyed it and subscribe to this channel for much more on dentistry if you'd like to support me please check out my patreon page and thank you to all of my patrons for their support you can unlock access to my video slides to take notes on and practice questions for the board exams so go check that out the link is in the description thanks again for watching everyone i'll see you in the next video [Music]