HOSA Studying (Dental Science) PDF - Study of Teeth & Oral Anatomy

Notes: Tooth Morphology - Study of the structure and form of teeth Eruption / eruption schedule - When the teeth grow and come up into the mouth (Ex. when babies get their teeth, and when baby teeth fall out and adult teeth come in) Dentition - Natural teeth in position in the...

Notes: Tooth Morphology - Study of the structure and form of teeth Eruption / eruption schedule - When the teeth grow and come up into the mouth (Ex. when babies get their teeth, and when baby teeth fall out and adult teeth come in) Dentition - Natural teeth in position in the mouth Posterior - The very back teeth (Ex. when our t-eeth are actually in our mouths we feel the jaws as being posterior) ○ Posterior teeth have (most of the time) 2 roots and multiple cusps Anterior - The front teeth Deciduous - Primary / Baby teeth ○ There are 20 deciduous teeth instead of the 32 adult / permanent teeth ○ These teeth stay in a kid’s mouth until the age of 6, and all the rest of the permanent teeth grow in between the ages of 6-17 Maxillary Arch - Upper set of teeth, set in the Maxillary bone ○ This arch is fixed to the skull  Mandibular Arch - Lower set of teeth, set in the Mandibular bone ○ This arch is mobile ○ It is what helps us chew and brings the biting force up towards the maxillary arch Both arches have the same number of teeth Teeth are designed to ensure proper function and positioning (i.e. teeth are made to chew, and also made to stay in the same position they grew into) ○ Teeth support the teeth beside and on top of / below (in the opposing arch) ○ This ensure that displacement and teeth movement does not occur The teeth in the maxillary arch (top arch) slightly overlap with the teeth in the mandibular arch (bottom arch) ○ This happens in proper alignment, sometimes teeth do not align properly (then you need braces and invisalign) Adjacent - Next to ○ All teeth adjacent to each other touch (except for the last teeth in both arches)  Midline - An imaginary vertical line that separates the mouth into four sections ○ This midline is also the line of reflection in a way ○ The right side of the teeth are the same as the left side Quadrant - The mouth’s dental arches split into four parts ○ Each quadrant has eight teeth ○ Each quadrant is a mirror image of the quadrant next to it ***Quadrants are labeled based on THE PATIENT’S LEFT AND RIGHT  Deciduous teeth (baby teeth) have 20 teeth, 10 in each arch and 5 in each quadrant Other than quadrants, the teeth can also be divided into sextants (sixths) Deciduous Teeth Diagram Tooth Name Function Central Incisor Cut and bite food Lateral Incisor Cutting food Canine (Cuspid) Tears thicker foods like meats Molars Chewing food  Permanent Teeth Diagram Tooth Name Function Central Incisor Cut and bite food Lateral Incisor Cutting food Canine Tears thicker foods like (Cuspid) meats Premolar Pulverize and break down (Bicuspids) food (preparation for the molars to break down more) Molars Chewing food  Cusps - pointed / rounded part of the tooth ○ Canines are also called Cuspids Bicuspid - Another name for premolar ○ Premolars are sometimes called bicuspids since they have two cusps ○ This is sometimes wrong since some some premolars have three cusps instead of two Third molars are farthest from the midline and called Wisdom Teeth The teeth between the two cuspids (canines) are the anterior teeth Anterior teeth have: ○ Single roots ○ A Tearing Edge called in incisal edge (the red lines)  Deciduous dentition (Primary teeth) start eruption at around 6 months of age Typically, all 20 teeth have fully erupted by the age of 3 Mixed Dentition - When both deciduous (primary) and permanent teeth are in the dentition (jaw bone) / mouth ○ This lasts from the ages of 6-12 ○ After the age of 12, most of the deciduous teeth are gone Exfoliated - Shed or drop from the oral cavity Permanent dentition keeps coming in until the ages of 17-21 (wisdom teeth as well) Succedaneous - The permanent teeth “succeed” / replace specific deciduous teeth ○ Ex. the anterior teeth Nonsuccedanous - The permanent teeth that don’t “succeed” the deciduous teeth ○ Ex. The molars don’t succeed any teeth, they come in as the jaw grows naturally   9.5 (first picture) is how a 7-8 year old’s teeth look like ○ The blue teeth are Succedaneous teeth that have the next teeth below them 9.6 (second picture) is how a 5 year old’s teeth look ○ The green teeth are Nonsuccedaneous teeth that DO NOT have the next teeth below them ○ They are growing straight through the bone, and don’t have any tooth before Gingiva - The tissue of your jaws that surrounds the base of the teeth. Cementum - A layer of hard dental tissue covering the anatomic root Crown - The part of your tooth that you can see (Most of the time) ○ Clinical Crown - The part you CAN see (No matter what)  ○ Anatomical Crown - The part that is still the crown, but you can’t see This can be caused by naturally or by an inflamed gingiva (example) Root - The bottom part of the tooth that you can’t see that is connected to the bone ○ Clinical Root - A part of the root that is seen, whether it be due to gum recession or just naturally Sometimes when periodontists and other specialists will refer to the clinical crown as being the visible crown and root segments So, sometimes this is useless ○ Anatomical Root - The part of the root that is under the gingiva and NOT SEEN Cervical line - The line that separates the root and the crown ○ Its derived from the word cervix which means “neck of” ○ The cervical line is also called the Cementoenamel Junction (CEJ) Different Parts of the Teeth: ○ Proximal Side - The side that touches / faces the tooth next to it (this includes both left and right side of the tooth)  ○ Mesial Side - The side towards the midline ○ Distal Side - The side away from the Midline ○ Labial Side - The side that touches your lips (specifically for the anterior teeth) ○ Lingual Side - The inside side of the teeth (For all teeth) On the maxillary (top) arch, it's also called the Palatal Surface ○ Incisal Edge - Cutting edge / top part of the tooth ○ Buccal Side - The side that touches your lips (specifically for the posterior teeth) ○ Occlusal Side - The top part of molars that do the chewing Types of tooth surfaces: ○ Convex - Outward curving surface ○ Concave - Inward or dented curved surface Teeth Crown - Thirds: ○ *Incisal Third* (ONLY IN ANTERIOR TEETH) - The third of the tooth closest to the incisal edge (the top edge of the tooth) ○ Occlusal Third (ONLY IN POSTERIOR TEETH)- The top third of the tooth closest to the occlusal side (chewing surface) of the tooth ○ Cervical Third - The third of the tooth closest to the cervix / gingiva (near the gums of your teeth) ○ Middle Third - The space between the Incisal Third and the Cervical Third Apex - The very end tip of a tooth’s root Root of Tooth- Thirds (Same for anterior and posterior): ○ Cervical Third - The third closest to the crown (This is opposite from the crown version; that is the crown closest to the gingiva and this is the root closes to the crown) ○ Middle Third - The middle part of the root ○ Apical Third - This is the apex / very bottom part of the root  These thirds are used by dentists to describe teeth, as well as do specific diagnosis Contact Area - The area where two teeth come together (the proximal sides of two teeth come together) ○ The contact area is usually in the middle third of the crown ○ This is the area you floss ○ This makes sure teeth don't move and shift ○ There is usually a little triangular gap under the contact area where food gets stuck Diastema - Space between two teeth ○ Usually used to talk about a gap in the maxillary central incisors (two ○ teeth) Embrasure - The triangular space in the gingival direction (Downwards in this case) where two teeth touch ○ This is also where you floss Apical Foramen - A small hole (or holes in some cases Ex. molars will have a hole in each apex, thus 2 - 3 holes) where the nerves and blood vessels go through  Bifurcated - When the nerves and blood vessels fork in through two holes Buccal Groove - a Linear grove in the posterior teeth that goes from the middle of the buccal area of the tooth (touches your cheeks) to the occlusal area of the tooth (chewing area) ○ The end of the groove (the part that touches your cheek) is the Buccal Pix Cingulum - A convex (outward pointing) area on the lingual (interior) part of your anterior teeth at the bottom (near the gingiva) Cusps - The round / pointy mound on posterior teeth Cusp of Carabelli - A fifth cusp located on the mesial (close to the midline) side of most maxillary first molars (all other molars have 4 cusps) Lobes - the separate parts that fuse together to make teeth crowns ○ In molars, the lobes usually become cusps  Developmental Groove - The middle grove in the occlusal surface (top chewing part of molars) that is made from the fusing of the lobes Fissure - An imperfect version of the developmental groove where the lobes did not fully connect properly ○ Bacteria and infection can start in fissures Fossa - small depressions in teeth (they can be round or angular) ○ The picture has 2; disto-lingual means away from the midline and on the inside (tongue touching) side of the teeth ○ Mesio-Lingual means towards the midline and on the inside (tongue touching) side of the teeth Furcation - The part where a multi-root tooth splits from one crown into two separate roots Mamelons - The three little bumps you have on your anterior when your permanent teeth erupt  Ridge - Linear elevation of enamel on teeth Marginal Ridges - Little borders on the mesial (close to midline) and distal (away from midline) areas of teeth on the lingual (tongue side) of the tooth Oblique Ridge - Elevated enamel that extends obliquely (slantedly) across the occlusal (chewing surface) of morals ○ On maxillary first molars, the oblique ridge goes from disto-buccal cusp (the cusp away from the midline that touches the cheek) to the mesio-lingual-cusp (the cusp the is towards the midline that touches the tongue) Pit - The spots where grooves come together / where fissures cross ○ The fissures and grooves as the longer lines across the teeth ○ The pit is the area where they come together and go a little deeper inwards  Supplemental Groove - Small grooves that branch off of the developmental groove Triangular Ridge - Ridge / elevation that goes from the cusps to the middle occlusal (chewing surface) of posterior teeth ○ As it goes towards the cusps, the ridge widens making a triangle Transverse Ridge - The combination of two triangular ridges that ends up making a small section of an elevated ridge Trifurcated - Three roots coming from the same trunk / crown of a tooth Maxillary Central Incisors: These are the front two teeth on the top arch They are important to a person’s appearance ○ They shape, color, and size of these teeth have a big impact on a person’s overall smile They also support the face and lips, thus having them in the proper spots is important These teeth are also important for pronouncing sounds like the S sound and the T sound These teeth do not have cusps, instead they have an incisal edge that helps bite and cut foods to prepare for the morals When the central incisors and the lateral incisors come in, they have 3 mamelons (the bumps) ○ These mamelons are caused by the lobes coming together to create the tooth As time goes on, the mamelons flatten because of attrition (everyday wear) Imbrication Lines - Three faint curved lines that are present in central incisors near the gingival area on the labial (lip facing) side CEJ - The cemento-enamel junction; this is the separation where the crown ends and the root begins  The Maxillary Central Incisor has the longest crown of any maxillary tooth The labial (lip facing) surface in this tooth is FULLY CONVEX (it is shaped outward from mesial to distal and gingival to incisal The lingual (toung facing) surface is mostly concave ○ The only part that in convex is the gingival-third where there is the Cingulum The cingulum spreads from mesial to distal in an arch pattern ○ This later forms the marginal ridges The mesial (close to midline) surface is slightly longer than the distal (away from midline) surface The mesial-incisal side (bottom sharp side) of the tooth has an approximate 90 degree angle The distal-incisal side is more rounded The root is 1.5 - 2 times as long as the crown The starts off at the CEJ to get skinnier than the crown It then widens up when it gets to the root and tapers off again at the apex Maxillary Lateral Incisors: This is the second tooth from the midline The Maxillary Lateral Incisors very similar to the central incisors The Maxillary Lateral Incisors are the smallest teeth in the max-arch The maxillary lateral incisors are 3/10ths smaller than the central incisors next to them The length of the root is also smaller, but similar to the central The crown of the lateral is narrower than the central ○ This is especially true in females The distal-incisal edge is even more rounded than the central The length of the distal side is a lot shorter than the mesial side Anomalies - Teeth that vary from the normal version of the tooth The max-lateral incisors have a lot of anomalies Peg Laterals - A type of anomaly where the lateral incisor crown is peg shaped and smooth. It does not touch any of the surrounding teeth ○ This is the most common type of lateral anomaly Agenesis - When the tooth buds do not form properly. The root is curved and either a distorted crown will appear or no crown at all ○ These can appear generation after generation Maxillary Canine (Cuspids): Called the “Cornerstone of the mouth” since they are at the corner of your smile This tooth turns the corner of the arch and rounds the arch Canines are used to tear hard foods like meats The canines are very important for supporting facial muscles Canine Eminence - The liable (lip facing) part of the bone that contributes to a person’s upper lip appearance Canines have the longest and most stable roots of the maxillary arch The crown is convex towards the labial (lip facing) side Canines have a ridge running vertically The pointy edge is slightly off center towards the mesial side The mesial side of the canine is longer than the distal side Canines are more rounded than both of the incisors Canines have 2 concave fossas on the lingual (tongue facing) side ○ One is on the mesial side and one is on the distal side  ○ There is a lingual ridge dividing both of them On the outer sides of the fossas, there are the marginal and distal ridges Maxillary First Premolar (Bicuspid): From the front (facial side), the first premolar looks a lot like a cuspid ○ This is because the labial (lip facing side) is a lot longer and wider than the lingual side The cusps come together on the occlusal (chewing surface) to make a central groove The central groove extends to become the mesial and distal grooves These two grooves are bordered by the mesial / distal marginal ridges This first premolar is bifurcated (two roots) that are slightly separated ○ One root is on the labial (lip facing) side and the other is on the lingual side The roots are shorter and resemble the roots of molars There is a slight depression in the roots of this tooth ○ This makes this tooth more susceptible to gum disease The first premolar does not have the biggest effect on a person’s appearance ○ That's why it is sometimes removed during orthodontics ○ The positioning of the premolars also allow movement from both the anterior and posterior teeth Maxillary Second Premolar (Bicuspid): Very very similar to the first premolar The only differences are as follows: ○ The cusps on this premolar are closer in size to each other, and thus look more like a molar than a canine ○ The cusp slope between the mesial-buccal cusp and the distal-buccal cusp is shorter than on the first premolar ○ The second premolar only has one root ○ The depression in the mesial root is more shallow than in the first premolar ○ Both the first and second premolars are wider bucco-lingually than mesio-distally This means they are wider front to back as opposed to left to right ○ The second premolar is more narrow mesio-disstally (Left to Right) than the first premolar Maxillary First Molar: Also called the “6 year molar” ○ This is because its eruption time at around 6 years old  The first molar is square in shape and has 4 cusps ○ Mesio-Buccal, Mesio-Lingual, Disto-Buccal and Disto-Lingual There is also a fifth mini cusp, the Cusp of Carabelli on the side of the Mesio-Lingual cusp In between the Mesio-Buccal and the Disto-Buccal cusps, there is the Buccal Groove that extends half the length of the buccal (cheek facing side) side of the crown ○ The buccal groove ends at the Buccal Pit The lingual cusps are a little bit longer than the buccal cusps Mesio-Lingual and Disto-Lingual cusps are separated by the Lingual Groove that extends half the length of the lingual (tonge facing side) side of the crown ○ The buccal groove ends at the Lingual Pit The root is Trifurcated (three roots)  The first two roots are the Meso-Buccal and Distal-Buccal roots (cheek facing roots) ○ These two roots are curved towards each other The third root is on the lingual side, and is the largest and longest root of the three Each root has its own canal On the occlusal (chewing) surface of the tooth, the 4 cusps come together to make the Central Fossa The Oblique Ridge connects the Mesio-Lingual cusp to the Disto-Buccal cusp The Transverse Ridge connect the Mesio-Lingual cusp to the Mesio-Buccal cusp The distal side of the molar has the distal marginal ridge occlusal surface The mesial side of the molar has the mesial marginal ridge on the occlusal surface All of these ridges make the occlusal surface of the molar textureful and makes it easy to grind food Maxillary Second Molar: This is called the “12 year molar” because of the age of eruption The second molar has both a smaller crown and a smaller root than the first molar The second molar has 4 cusps with the same names of the first molar (no mini cusp) ○ They are: Mesio-Buccal, Mesio-Lingual, Disto-Buccal and Disto-Lingual The mesial side of the tooth is wider than the distal side of the tooth The occlusal surface of the molar is smaller, but it does the same thing as the first molar Supplemental Groove - shallow grooves on the occlusal part of a tooth The second molar has more supplemental grooves, making it look more wrinkled than the first molar The second molar’s roots are slightly closer together than the first molar’s Maxillary Third Molar (Wisdom Teeth): There are many different variations of the third molar, so there is no one shape or size for it They get the name “wisdom teeth” because they come when a person is more mature / wise Lots of people don’t develop third molars If someone does develop third molars, they usually don't erupt properly in the oral cavity because there isn’t enough space A dentist may recommend someone to get this molar removed If the wisdom teeth have enough space to erupt naturally, they will be very similar to the second molar, only a little bit smaller There are even more grooves than the second molar, so this tooth looks even more wrinkly Wisdom teeth have no definitive number of roots, but the roots are fused together Mandibular Central Incisor : This is the least variable (most predictable) tooth in the mouth This is the smallest tooth in the permanent teeth dentition Opposite to the maxillary arch, the bottom central incisor is smaller than the bottom lateral incisor  Same as the maxillary central incisors, these mandibular central incisors also erupt with three small mamelons ○ These mamelons go away pretty soon after eruption The labial (lip facing) side is convex, and has no depressions or imbrication lines (unlike the maxillary centrals) The crown is narrow and makes sharp 90 degree angles at both the mesial and distal ends The lingual (tongue facing) side is concave, except for the cingulum near the gingiva The root is a long triangle that ends at the apex Mandibular Lateral Incisor : Basically the exact same as the maxillary lateral incisor The mandibular lateral is a little bit bigger (root and crown) than the maxillary Sometimes, the mesial and distal sides are a little bit concave ○ If this happens, the mesial side is shallower than the distal side The lateral incisor is shaped as the mandibular lateral incisor ○ The only difference is that the lateral incisor has a shorter and slightly rounded distal side There are no abnormalities in this tooth, unlike the maxillary Mandibular Canine (Cuspid) : Third tooth from the midline Same as the maxillary canine, but slightly less developed than the maxillary canine and a little bit less sharp The crown is the almost the same length as the maxillary canine, but the root is shorter ○ It is still longer than the mandibular central and lateral incisors, but not as long as the maxillary canine The distal cusp slope is longer than the mesial cusp slope The cingulum and marginal ridges are not as prominent as on the maxillary canine The more prominent buccal ridge helps give shape to the face The canine is the longest tooth in the mandibular The tooth has deep depressions on the mesial and distal sides Mandibular First Premolar (Bicuspid) : This tooth acts more like a transition tooth It looks more similar to a mandibular canine It has two cusps; one lingual and one buccal The lingual cusp is almost always nonfunctioning, and looks a lot like a mandibular canine The buccal cusp is larger and has a more pronounced convex shape Like in mandibular canines, the mesial cusp slope is shorter than the distal cusp slope The tooth has both distal and mesial ridges As the buccal and lingual cusps come together, a transverse ridge crosses the tooth The root of this tooth is even shorter than the mandibular second premolar There is slight bifurcation (the nerves split through two holes) at the apex Mandibular Second Premolar (Bicuspid) : This tooth is similar to the mandibular first premolar, but this tooth is less long and more wide  The cusps on this second premolar are more developed, and have up to 3 functioning cusps This tooth helps transition from cutting food to chewing food The occlusal surface of this tooth is similar to the molars The lingual (tonge facing) cusps are shorter than the buccal (cheek facing) cusps The lingual and buccal cusps are divided by the lingual groove The mesio-lingual cusp is a little bit bigger than the disto-lingual cusp Bicanineate - Two cusp second premolar Bicanineate second premolars are not very common ○ These are made of a large buccal cusp and a lingual cusp ○ The occlusal groove pattern can be in the ‘H’ pattern or in the ‘U’ / ‘C’ pattern Tricanineate - Three cusp second premolar Tricanineate second premolars are more common ○ They have 1 buccal cusp and 2 lingual cusps ○ The groove pattern usually looks like a ‘Y’ All of the cusps into these grooves in the middle  The root for this tooth is shorter than the maxillary canine, but bigger than the mandibular first premolar The root is a single canal that is angled slightly towards the distal Mandibular First Molar: All of the mandibular molars are the biggest and strongest teeth in the mandibular arch Also called the ‘6 year molar’ since it erupts at 6 years old ○ Usually erupts a little bit earlier than the maxillary first molar In considered the keystone of the dental arch Is the largest mandibular tooth and has the widest crown in the mouth This has FIVE functioning cusps!!! The Mesio-Buccal cusp is the bulkiest / thickest and longest of the three buccal cusps ○ But it is shorter than the lingual cusps The Disto-Buccal cusp is a round cusp found in between the bigger Mesio-Buccal cusp and Disto-Lingual cusp The Disto-Lingual and Mesio-Lingual cusps are the longest and sharpest on this molar ○ The Mesio-Lingual cusp is sometimes a little bit smaller than the Disto-Lingual cusp All the cusps come together on the central fossa  The buccal groove separates the mesio-buccal cusp and the disto-buccal cusp ○ It ends halfway down the buccal surface of the crown at the buccal pit The mesial side of the tooth is a little bit concave (inward) The distal side of the tooth is pretty straight This tooth has two roots; Distal and Mesial ○ The mesial root is stronger and wider  The mesial root usually has two pulp canals, meaning there are two holes where the nerves go through on the same root The root is pretty flat It curves first towards the mesial side then back towards the distal side The distal root is smaller and weaker The distal root is usually pretty straight, but might sometimes curve a little bit The distal root usually has a wider canal The outside of the distal root is convex (outwards) Mandibular Second Molar: A smaller version of the first molar It has 4 cusps: ○ Mesio-Buccal, ○ Mesio-Lingual, ○ Disto-Buccal and ○ Disto-Lingual They are all basically the same size, but the Mesio-Buccal is a little bit bigger and Disto-Lingual cusp is the smallest The are divided by the buccal groove and the lingual groove  Both of these grooves go down the sides of the tooth (around half of it) They end with pits or shallow depressions This second molar has more supplementary grooves than the first mandibular molar The roots of the second mandibular molar are shorter than the first molar The second molars have two bifurcated roots that are typically pretty close to each other ○ Sometimes they can even be fused together The second molar roots are angled towards the distal side The mesial root is wider and can sometimes have two canals in one root They are similar to the first molar roots, but the mesial root is flatter and the distal root is rounder Mandibular Third Molar (Wisdom Teeth): Many variations of different shapes and sizes Is like a smaller version of the second molar (If it properly erupts) The third molar have a very wrinkled surface The roots are often fused together The roots angle so far towards the distal direction that sometimes it seems like the roots are horizontal instead of vertical There can be up to four roots, all that can be fused together  They are usually very hard to clean Deciduous (Primary / Baby) Teeth: There are a total of 20 teeth in deciduous dentition Deciduous teeth can be called: ○ Primary Teeth ○ Milk Teeth ○ Baby Teeth ○ First Teeth They start erupting at 6 months, and finish erupting at 2-3 years of age People don’t care that much about baby teeth since they think that the permanent teeth will come in afterwards anyways But baby teeth are very important because they teach kids about mastication (chewing) and phonetics (speaking) Baby teeth also also help establish a kids positive self image Baby teeth start exfoliating (falling out) at age 6, but they are still an important part of facial development The crown of baby teeth is very small compared to the root The cervical ridge (separation between crown and root) is more pronounced and obvious Baby teeth are a lot whiter and sometimes a little blueish compared to the yellow-gray of natural permanent teeth  The enamel and dentin (The layer directly under the enamel) are a lot thinner in baby teeth, but the pulp is a lot bigger Pulp Horns - Extensions of pulp that go up into cusps The deciduous molars have really big pulp horns in the mesial side Because of this, the pulp is a lot closer to the surface of the deciduous tooth Deciduous Maxillary Central Incisor: The Deciduous Maxillary Central Incisor is very similar to the permanent maxillary central incisor The only big difference is their size, the deciduous Deciduous Maxillary Central Incisor is a lot smaller The Deciduous Maxillary Central Incisor is also the only tooth in both dentitions that is wider than it is tall This tooth does not have any mamelons when it erupts The labial (lip facing) surface of this tooth is convex and smooth Deciduous Maxillary Lateral Incisor: The Deciduous Maxillary Lateral Incisor is similar to the Central Incisor in many ways But it is smaller than the central incisor This tooth is also longer than it is wide The Deciduous Maxillary Lateral Incisor has a more rounded incisal edge at the mesial and distal sides that the straight incisal edges of the central incisor Deciduous Maxillary Canine (Cuspid): The Deciduous Maxillary Canine seems very wide, but the canine is actually longer than it is wide It is more convex than the permanent maxillary canine It is more constricting and inward at the cervix (neck) of the tooth There is a pronounced cingulum, as well as mesial and distal marginal ridges The root is similar to the Deciduous incisors, but longer ○ Not even close to the permanent canine Deciduous Maxillary First Molar: This tooth is very similar to the permanent first premolar It has four cusps; the mesio-buccal and mesio-lingual are the most prominent The mesio-lingual cusp is the biggest and longest The disto-lingual is the smallest ○ Sometimes is is absent and doesn’t appear on the tooth The tooth has both oblique and transverse ridges, but they are not as prominent as with permanent teeth The tooth has 3 roots that spread rapidly and are widely spaced Deciduous Maxillary Second Molar: Basically the exact same as the first molar It has 4 primary cusps, but sometimes has a Cusp of Carabelli It has 3, widely spaced roots Deciduous Mandibular Central Incisor: Is very similar to the permanent mandibular lateral incisor The crown of the tooth is a little wider than the permanent mandibular lateral incisor The shape and form is almost the exact same as the permanent mandibular lateral incisor The root of the tooth is slender and pretty long Mesial and distal surfaces are flat, while lingual and labial surfaces are convex Deciduous Mandibular Lateral Incisor: Very similar to the Deciduous Mandibular Central Incisor ○ Only real difference is that the central incisor is longer and wider The cingulum, as well as the mesial and distal marginal ridges are more pronounced The Fossa is not as shallow as on the central At the apex of the root, the root curves towards the distal direction Deciduous Mandibular Canine (Cuspid): A lot more delicate than the Deciduous Maxillary Canine The root is shorter and smaller The cingulum, as well as the mesial and distal marginal ridges are less pronounced than the Deciduous Maxillary Canine The mesio-incisal slope is not as long as the disto-incisal slope ○ This is kind of similar to the mandibular permanent canine Deciduous Mandibular First Molar: This tooth resembles literally no other tooth It has four cusps The biggest cusp is the mesio-buccal cusp The second biggest cusp is the mesio-lingual cusp The disto-lingual and disto-buccal cusps are a lot smaller than the mesio cusps The buccal (cheek facing) surface is longer than the lingual (tongue facing) surface The buccal surface has a cervical ridge (separation between crown and root) The tooth has two roots; mesial and distal  The mesial root is a lot longer and wider The apex of the mesial root is flattened / squared off Deciduous Mandibular Second Molar: Very similar to the permanent mandibular first molar It is smaller than the permanent mandibular first molar It has 4 cusps The mesio-buccal and disto-buccal cusps are almost the same size The mesial root is longer and wider The distal root is smaller The roots of the Deciduous Mandibular Second Molar are almost the same size as the permanent mandibular first molar