Oral Anatomy Study Guide PDF

Chapter 1: Oral Anatomy The Face Area Eyesnosecheeks andlips Includes the eyes, nose, cheeks, and lips Plays a crucial role in facial expression and function Oral Tissues softissue gumtonguelips hard tissueteethandpalate...

Chapter 1: Oral Anatomy The Face Area Eyesnosecheeks andlips Includes the eyes, nose, cheeks, and lips Plays a crucial role in facial expression and function Oral Tissues softissue gumtonguelips hard tissueteethandpalate Includes the soft tissues (e.g., gums, tongue, lips) and hard tissues (e.g., teeth, palate) Responsible for various functions like chewing, swallowing, speech, and taste The Roof of the Mouth Also known as the palate keratinized Divided into the hard palate (anterior) and soft palate (posterior) Plays a role in swallowing and speech The Throat Area Includes the pharynx and larynx  Involved in swallowing and phonation The Floor of the Mouth Includes the tongue and surrounding soft tissues Facilitates speech, swallowing, and taste The Tongue Muscular organ in the floor of the mouth Plays a key role in taste, swallowing, and speech Chapter 2: Tooth Anatomy The Crown surface above gumline The visible portion of the tooth above the gum line Composed of enamel (outer covering), dentin, and pulp (innermost layer) The Root The portion of the tooth below the gum line Composed of cementum (outer covering), dentin, and pulp  Tooth Surfaces ProximalSurfaces Lingual: The surface facing the tongue Facial: The surface facing the cheek or lips Buccal: The surface facing the cheek Mesial: The surface closest to the midline of the dental arch Distal: The surface farthest from the midline of the dental arch Proximal: The surfaces between adjacent teeth Contact area Occlusal/Incisal: The chewing surface of posterior/anterior teeth Tooth Surfaces (Detailed) Incisal/Occlusal: The biting/chewing surface Cervical: The area near the gum line Apical: The area near the root tip Mesial: The surface closest to the midline Middle: The central portion of the tooth Distal: The surface farthest from the midline Line Angles  Anterior Teeth: o Labioincisal o Mesiolingual o Mesiolabial Posterior Teeth: o Mesio-occlusal o Mesiolingual o Mesiobuccal o Bucco-occlusal o Linguo-occlusal o Distolingual o Distobuccal o Disto-occlusal o Linguoincisal o Distolingual o Distolabial Point Angles Anterior Teeth: o Mesiolabioincisal o Mesiolinguoincisal o Distolabioincisal o Distolinguoincisal Posterior Teeth: o Mesiolinguo-occlusal o Mesiobucco-occlusal o Distolinguo-occlusal o Distobucco-occlusal Tooth Terminology Tubercle: Small elevation of enamel on the crown Fossa: Depression or concavity on the tooth surface Pit: Pinpoint hole in a fossa or elsewhere on the tooth Cusp: Mound on the crown that makes up a major division of the occlusal or incisal surface Ridge: Elevated portion of a tooth that runs in a line Developmental Grooves: Remain after the fusion of tooth lobes Anterior Teeth Labial development grooves: Two grooves on the labial surface that separate the three lobes Lingual groove: Separates the labial development grooves from the fourth lobe on the lingual surface Posterior Teeth Cusps: Most obvious landmarks, varying in number depending on the tooth Triangular Ridges: Main ridges on each cusp, running from the cusp tip to the central occlusal surface Transverse Ridge: Union of two triangular ridges crossing the occlusal surface  Chapter 3: Tooth Relationships Contact Areas and Interproximal Spaces Contact Area: Flattened portion of the tooth where it touches the adjacent tooth Contact Point: Where the occlusal cusp of one tooth touches the occlusal portion of another tooth in the opposing arch Interproximal Spaces: Triangular-shaped spaces between teeth, formed by bone and the proximal surfaces r Embrasures n Cervical Embrasure: Occurs when there is gingival recession, and the interdental papilla and bone no longer fill the entire interproximal space Embrasures (Spillways): Spaces between teeth that are occlusal to the contact areas Tooth Contours Direct food off teeth and against the gingiva at the proper angle Too much deflection = not enough gingival stimulation Too little deflection = allows food to pack into the gingival crevice Allow the tongue to rest against the tooth Facial height allows for maximum cleaning of lips and cheeks Cervical Line Curvature The curvature of the cementoenamel junction (CEJ) depends on the height of the contact area and the diameter of the crown The mesial curvature of a tooth is greater than the distal curvature CEJ Mandibular anterior teeth show less curvature than their maxillary counterparts Periodontium The supporting structures of the teeth, including the gums, alveolar bone, cementum, and periodontal ligament Chapter 4: Dental Arches and Dentition Dental Arches Maxillary Arch: The upper dental arch Mandibular Arch: The lower dental arch Each arch is divided into four quadrants: RMx LMx o Right Maxillary o Left Maxillary o Right Mandibular o Left Mandibular 9 RM LM Dentition Primary Dentition: 20 deciduous (baby) teeth Secondary Dentition: 32 permanent teeth Atot Tooth Naming and Coding Systems Universal System: Numbers teeth 1-32 from right to left, maxillary to mandibular Palmer Notation System: Uses quadrant numbers and tooth position numbers FDI System: Uses a two-digit system to identify each tooth Chapter 5: Tooth Development and Eruption Calcification The hardening of tooth tissues by the deposition of mineral salts Mamelons The incisal ridges of the three labial developmental lobes on newly erupted incisors Separated by developmental grooves and only present when incisors first erupt Premolar Lobes and Cusps Maxillary Premolars: Three facial lobes and one lingual lobe Mandibular Premolars: First has the same number and arrangement as maxillary, second may have 2 or 3 cusps with three occlusal types (U-shaped, H-shaped, Y-shaped) Molar Lobes and Cusps 2ndpremolar  Have two facial and two lingual lobes Exception: First maxillary molars usually have a fifth or minor lobe (lobe of Carabelli's or cusp of Carabelli) Each lobe develops a cusp Second molars are usually much smaller than first molars in all cusp proportions Third molars are the most unpredictable of all teeth Tooth Eruption Eruptbeforemaxillary Mandibular teeth usually precede maxillary teeth of the same type Teeth generally appear in pairs, one on the right and one on the left Permanent teeth erupt slightly earlier in girls than in boys Eruption Timing Mandibular Central Incisors: ~6-8 months Maxillary Central Incisors: ~2 months later PrimaryTeeth Maxillary Lateral Incisors: ~1 year old Mandibular Lateral Incisors: ~1-2 months later Mandibular and Maxillary First Molars: ~16 months Canines: ~16-20 months Second Molars: ~2 years old Permanent Mandibular First Molars: ~6 years old First Endand Permanent Maxillary First Molars: A few weeks later permanent Permanent Mandibular Central Incisors: ~6-7 years old ftp.PIayaiarsmand Permanent Maxillary Central Incisors: ~7-8 years old MaxandMand Permanent Lateral Incisors: ~7-9 years old LateralIncisors Permanent Mandibular Canines: ~9-10 years old MandibularCanines Mand Permanent First Premolars: ~10-12 years old molars Maxand Mand First pre and Permanent Second Premolars: ~10-12 years old secondpremolarsMax Permanent Maxillary Canines: ~11-12 years old MaxillaryCanine Permanent Second Molars: ~11-13 years old SecondMolars Max andMand Permanent Third Molars: ~17 years old+ Third Molars MaxandMand Mesial Drift Permanent molars have a tendency to erupt and move mesially (toward the midline) Can cause problems if a deciduous tooth was lost prematurely or if premolars and canines have not yet erupted Exfoliation of babyteeth Rootsdissolved are The process by which the roots of a deciduous tooth are dissolved (or resorbed) so that the tooth can fall out Occurs as the permanent tooth erupts, with osteoclasts destroying the deciduous root Occlusal Plane Forms as teeth erupt and meet their antagonist in the opposite arch Called the curve of Spee unless it is flat Allows for more occlusal space than a flat line Only flat if no teeth are crowded in the arch Comprehensive Study Notes: Chapters 8, 10, and 11 Chapter 8: The Tissue Gingival Unit Coronally feasted Free Gingiva: The portion of the gingiva that is not attached to the tooth Attached Gingiva: The portion of the gingiva that is firmly attached to the underlying alveolar bone Alveolar Mucosa: The thin, freely movable tissue that lines the rest of the mouth Attachment Unit (Attachment Apparatus) Cementum: Calcified tissue covering the root of the tooth Sharpey's Fibers: Embedded in the cementum or alveolar bone, keeping the gingiva closely attached to the tooth surface Periodontal Ligament: Connects the cementum to the alveolar bone Alveolar Process Bony structure that houses the tooth sockets (alveoli) Composed of cortical and trabecular bone, as well as basal and bundle bone Mucosa Alveolar Mucosa: Thin, freely movable tissue that tears easily Underlying Mucosa: Dense collagen fibers, also found on the hard palate EEE man  Masicatorymucosa Keratinizedcells Masticatory Mucosa: Thick, keratinized epithelial covering of the free and attached gingiva Other Components sulcus between tooth and free gingiva Sulcus: Space between the tooth and the free gingiva Dentinogingival Junction: Where the tooth surface meets the gingival tissue Junctional Epithelium: Specialized epithelium that attaches the gingiva to the tooth Chapter 10: Anterior Teeth and Premolars Anterior Teeth Incisors: Forcutting bittingintofood o Incisal edge is more square mesially Incisa endge squareMesial is o Maxillary centrals are the widest mesiodistally with a well-developed lingual cingulum o Maxillary laterals are smaller than the centrals o Mandibular centrals are hard to distinguish, and the root may tip mandibles distally o Mandibular laterals are larger than the mandibular centrals Canines: cuspids gripping tearing achefstentrals Buffyggfᵈ o Maxillary canines have the bulkiest crowns and a well-developed lingual cingulum o Mandibular canines have a smoother lingual surface Premolars Bicuspids 2cusp each point Maxillary Premolars: o Have two major cusps (buccal and lingual) o Wider faciolingually than Zmajor cusps mesiodistally buccal lingual o First premolars typically have two roots (buccal and lingual) with mesial depressions and grooves o Second premolars usually have one root and no mesial depression maxists 2nd Mandibular Premolars: Max o Have a prominent facial cusp and one or two lingual cusps o Nearly equal faciolingual and mesiodistal widths treat o First premolars have an obvious transverse ridge and no central pit o Mandibular Second premolars have no transverse ridge but have a central pit and a premolars distinguishable occlusal surface navelor es transverse Chapter 10: Molars Crushing andgrindingfood molar Maxillary Molars Crowns are wider faciolingually than mesiodistally see Have three roots: two on the facial side and one on the lingual side First molars often have a fifth cusp, and the mesiolingual cusp is larger than the distolingual cusp Second molars have no fifth cusp, and the mesiolingual cusp is larger than the distolingual cusp; the roots are closer together than the first molars Mandibular Molars Crowns are wider mesiodistally than faciolingually created t.EE Have two roots: one mesial and one distal First molars have three facial cusps and two facial grooves, with the distal cusp being the smallest facial cusp u Efci Second molars have two facial cusps and one facial groove, with the buccal height ofeEfEe contour in the cervical third and the lingual in the middle third Chapter 11: Roots Sensory System Pulp tissue in the inner part of the root contains nerves that only emit a pain response when stimulated Common stimuli include dehydration, rubbing with an instrument, friction, and abrasion Nourishment Arteries, veins, and lymph tissue nourish the tooth from the inside Remove harmful products and carbon dioxide Apical foramen is the orifice in the apex of the root where vessels enter and exit If vessels are restricted, nerves and other tissues can die Support or Anchorage The amount of resistance a tooth can handle is affected by its width, shape, length, curvature, number of roots, concavity, and the direction of the periodontal fibers Other Root Information  Furcations: Rough surface areas where the roots diverge Enamel Pearls: Small enamel projections on the root surface Mobility: Affected by the periodontal ligament Root Canals Nerves and blood vessels leave the tooth through the root apex Anterior teeth usually have one large root canal per tooth, except for the mandibular canine, which sometimes has two Mandibular premolars usually have one canal, while maxillary premolars often have two Maxillary first molars usually have three roots and three canals, with the mesiobuccal root often having two canals Mandibular molars usually have two root canals, with the mesial canal being wider and bigger than the distal Anterior Teeth: Incisors and Canines Incisors Central Incisor crown of all incisors Anatomy of Incisors (Chapter 12) Largest Function food Shovel-shaped with sharp incisal edges Cut bite shear Wider cervical areas Lipsuppetsthetisech Crest of curvature in the cervical third of the crown Greater curvature of the cervical line on the mesial aspect than the distal Maxillary incisors have the greatest curvature of the cervical line (1) Maxillary Central Incisors Evidence of calcification begins at 3 months Erupt between 7-8 years Root completed by 10 years Widest mesiodistally of all anterior teeth 8 Straight mesial side, curved distal side Potential anomalies: short root, unusually long crown, gemination (1) Maxillary Central Incisor Facial Aspect FACIAL Developmental lines divide the surface into three parts, each separating a primary lobe Mamelons initially distinct, forming the incisal ridge 3 facial lobes of MesialOutline Convex development straight Slightly Distal Outlinethan Incisal Angle L More Convex RightAngle Sharp Angle Rod  morecurd camshape Straight Be.tt ftthenthecrow Slightly convex and very smooth (1) 4Borders MesialM Ridge Maxillary Central Incisor Lingual Aspect Irregular fossa depression Distal M Ridge One concavity with a cingulum Lingual Smooth convexity immediately below the cervical line outtingly cingulum May have 2+ lingual ridges Linguini'edge Usually developmental grooves extending from the cingulum into the lingual fossa Crown and root taper lingually (1) Maxillary Central Incisor Mesial, Distal, and Incisal Aspects Triangular crown Incisal ridge centered over the middle of the root wide Labial outline slightly convex Greater cervical curvature on the mesial surface than any other tooth Cervical line (CEJ) less curved on the distal (1) Mesial CEJ is the Maxillary Central Incisor Incisal Aspect largest Incisal ridge slopes lingually Crown has a triangular shape Crown apex on the lingual surface (1) Cingulume Maxillary Lateral Incisors moredistal Evidence of calcification begins at 1 year LINGUAL Erupt between 8-9 years smaller and rounded crown Root completed by 11 years longerroot Smaller in all dimensions except root length Vary more in form than any tooth except third molars Features more prominent than central incisors (1) Maxillary Lateral Incisor Facial Aspect 1 Long More curvature than central incisors Rounded incisal ridge Rounded angles medially and distally More convex labial surface than central incisors Root length greater in proportion to crown length than central incisors Root often 1.5 times the length of the crown (1)  Maxillary Lateral Incisor Lingual Aspect Mesial and distal marginal ridges pronounced Lingual ridges more convex than central incisors Cingulum usually prominent Fix Linguoincisal ridge better developed than central incisors Lingual fossa more concave and circumscribed than central incisors fossa is smalleranddeeper Lingual pit more frequently present (1) Maxillary Lateral Incisor Mesial, Distal, and Incisal Aspects Mesial aspect similar to a small central incisor, except the root appears longer Distal aspect same as mesial, except less curvature of the cervical line Incisal aspect resembles a central incisor or small canine, with a larger cingulum and incisal ridge, and more convexity (1) pronounced Maxillary Lateral Incisor Root Aspects cingulum Narrower mesiodistally than a maxillary central incisor thin root As long as the central incisor root but appears thinner Long Apical portion often curves distally and ends in a sharp apex (1) Mandibular Central Incisors Tip of the root point distally Evidence of calcification begins at 3 months Erupt between 6-7 years Root completed by 9 years Smallest teeth in the mouth smallest teethmouth Derived from four lobes: three labial and one lingual (1) Mandibular Central Incisor Facial Aspect Very smooth facial surface Gingivoincisal outline almost straight up and down Height of contour at the incisal third on both mesial and distal surfaces (1) Mandibular Central Incisor Lingual Aspect Cingulum much smaller than maxillary incisors  revenge No tubercle extensions or lingual pits Fossa very shallow (1) Mandibular Central Incisor Mesial, Distal, and Incisal Aspects Incisal edge tends toward the lingual half of the tooth, slanting labially Incised edge shows wear toward the facial aspect (1) Mandibular Lateral Incisors Evidence of calcification begins at 4 months Erupt between 7-8 years Root completed by 10 years Differentiation from mandibular central incisors: o Bigger, wider, longer o More prominent anatomic features on the lingual aspect o Slightly more convex and concave o Greater facial curvature o Endpoints of mesiofacial line angle farther apart than distofacial (1) Mandibular Lateral Incisor Facial Aspect More rounded appearance mesially and distally Developmental grooves deeper Height of contour at contact areas is at the incisal third (1) Mandibular Lateral Incisor Lingual Aspect Ridges more developed Fossa appears, with enamel tubercles often extending into it Lingual pit more often present than in central incisors (1) Mandibular Lateral Incisor Mesial, Distal, and Incisal Aspects Contour on labial and lingual surfaces higher at the gingival third Thicker at the linguoincisal ridge and narrower labiolingually Greater cervical curvature on the mesial side than distal Rounded general appearance, with deeper developmental grooves May appear rotated on the root axis (1) Mandibular Incisor Roots  Lateral incisor slightly wider, thicker, and longer than the central Lateral incisor apex may point labially or distally Proximal grooves commonly found on the root surface Three pulp horns, single root canal Canals are straight and narrow, with little variation Mandibular lateral canal is larger and may show more variation than the central (1) Canines Maxillary Canines (Chapter 13) Calcification at umonths Evidence of calcification begins at 4 months Eruption 11 12yearsof age Enamel completed between 6-7 years Root completedby 13 15409 roots Erupt between 11-12 years Longestteeth and long Root completed between 13-15 years Longest teeth in the mouth, anchored by extremely long roots Located in the corner of the mouth, with a special bony projection (canine eminence) Holding and tearing function, most stable teeth in the mouth (2) Maxillary Canine Facial Aspect Mesially straighter crown with slight convexity, distally rounded Root is slender compared to the crown, with a conical shape and blunt apex May have a sharp curve (2) care shaped root Maxillary Canine Lingual Aspect blunt apex gets Root tapers toward the lingual surface Well-developed lingual ridge from cusp tip to cingulum lingual fossa Two lingual fossae on either side of the lingual ridge 2 Well-developed cingulum, the largest of all anterior teeth (2) Gtepe'd cingulum Maxillary Canine Mesial and Distal Aspects Greater labiolingual bulk than other anterior teeth Labial surface more convex than other maxillary anterior teeth Shallow developmental depression from cervical line to root apex Mesial surface convex except for a flat space between contact area and cervical line Distal marginal ridge more developed and heavier in outline than mesial (2) Maxillary Canine Incisal Aspect Cusp tip is labial to the center of the crown labiolingually and mesial to the center mesiodistally Wider labiolingually than any anterior teeth (2) Maxillary Canine Root Usually the longest of any tooth, very strong and firmly embedded Apical portion often points distally but seldom mesially Root pointsdistally Large pulp chamber with a single pulp horn Gip Usually straight, may be curved with the root (2) Mandibular Canines Evidence of calcification begins at 4 months calcificationbegins at months Enamel completed by 7 years Eruption between 9 10 yeast Erupt between 9-10 years Rootcompleted Root completed by 13 years Y.ro a Similar to maxillary canines in general form Differences: o Crown slightly narrower mesiodistally o May have a longer crown, shorter root shorter root than maxillary canine o Lingual surface smoother, more like other mandibular anterior teeth o Cingulum less developed, marginal ridges less prominent o Cusp tip less in developed, cusp ridges thinner Dirt o May have bifurcated roots o Distal contact area more incisal (2) Mandibular Canine Facial Aspect smaller facial aspect Straighter mesial outline than maxillary canine, otherwise similar (2) Mandibular Canine Lingual Aspect Crown is flatter, lingual features less prominent Resembles other mandibular anterior teeth, except for a larger cingulum and pronounced lingual ridge (2) Mandibular Canine Mesial and Distal Aspects Less developed cingulum, thinner marginal ridges Cusp tip more lingually inclined 27  Cervical line curves more toward the incisal portion Root may be more pointed at the apex, with a more pronounced developmental depression Root may be bifurcated (2) 2 Mandibular Canine Incisal Aspect 85 Cusp tip is located more lingually compared to maxillary canines Incisal edge slants toward the lingual (2) Mandibular Canine Root Second longest root in the mouth, longest mandibular root May have a bifurcated root in the apical third Large pulp chamber, may have two separate root canals (one labial, one lingual) that join at the apex or have separate apical foramina (2) Premolars in General (Chapter 14) There are a total of 8 premolars, with 2 premolars per quadrant Premolars are immediately anterior to the permanent molars The lingual cusps of mandibular premolars are less functional compared to the maxillary premolars The first mandibular premolar can resemble the mandibular canine Premolars have shorter crowns and roots compared to the canines Compared to anterior teeth, premolars have: o Greater facial-lingual measurement in relation to the mesio-distal measurement o Broader and closer mesial and distal contact areas o Less curvature of the cervical line on the mesial and distal surfaces o Shorter crown measurements in the cervico-occlusal direction Maxillary 1st Premolar Eruption 10 11years of age Eruption: 10 to 11 years Buccalga.gl gyslspcnsp Has buccal and lingual cusps, with the buccal cusp usually being longer qf Typically has 2 roots: buccal and lingual FacingBuccal Lingual Maxillary 1st Premolar Buccal Aspect Similar appearance to the maxillary canine, but with a shorter and narrower crown short narrow crown 5 Ñ  WE Sharper mesial and distal marginal ridges Extremely well-developed middle facial lobe Tip of the facial cusp is distal to the midline Maxillary 1st Premolar Lingual Aspect Lingual cusp is shorter than the facial cusp Tip of the lingual cusp is slightly mesial to the midline Maxillary 1st Premolar Mesial Mesial marginal groove extends cervically from the mesial marginal ridge Mesial developmental depression is located cervically to the mesial contact area, continuing cervically to join the developmental depression between the roots Maxillary 1st Premolar Distal Similar to the mesial view, but without a groove crossing the distal marginal ridge and no developmental depression May have a distinct distal marginal groove Cervical line is less curved than on the mesial surface Maxillary 1st Premolar Occlusal Has two well-developed cusps, with the lingual cusp being more pointed and the facial cusp being larger and longer Each cusp has four ridges: facial, lingual, distal, and mesial Triangular ridge runs from the cusp tip to the central groove, eventually joining to form a transverse ridge Crown is wider on the buccal surface than the lingual Well-defined central developmental groove, mesial marginal developmental groove, mesiobuccal developmental groove, and distobuccal developmental groove Mesial triangular fossa harbors the mesiobuccal developmental groove Maxillary 2nd Premolar Eruption: 10 to 12 years Resembles the maxillary first premolar, but with more individual variation Crown is less angular and more rounded Root is usually longer and may be single or double 2CUSPS Triangular Ridge  give Maxillary 2nd Premolar Buccal Aspect Buccal cusp is shorter and less pointed than the first premolar Maxillary 2nd Premolar Lingual a o Lingual cusp is almost the same length as the buccal cusp Little variation from the first premolar Maxillary 2nd Premolar Mesial and Distal Y Mesial aspect has a shallow developmental groove Distal aspect shows features similar to the first premolar Maxillary 2nd Premolar Occlusal More rounded than the first premolar Greater distance between the cusp tips in the bucco-lingual direction Lingual cusp is almost as wide as the buccal cusp Comparison of Maxillary 1st and 2nd Premolars Feature1st Premolar2nd PremolarCrown ShapeMore angularMore roundedCusp LengthsBuccal cusp longerBuccal and lingual cusps more equalCusp SeparationLess distance between cuspsGreater distance between cusps Mandibular 1st Premolar RE.EE Eruption: 10 to 12 years Similar in appearance to the mandibular canine Dominant facial cusp Smaller than the mandibular second premolar Single-rooted Mandibular 1st Premolar Buccal Aspect Well-developed middle buccal lobe Sharp buccal cusp 28  Mesial cusp ridge is shorter than the distal Mandibular 1st Premolar Lingual Lingual cusp is small Occlusal surface slopes lingually in a cervical direction Mesiolingual developmental groove separates the mesial marginal ridge from the lingual cusp Mandibular 1st Premolar Mesial Mesiolingual developmental groove is visible between the mesiobuccal and lingual lobes Mandibular 1st Premolar Distal No mesiolingual developmental groove is evident Distal marginal ridge is more developed than the mesial, with unbroken continuity Mandibular 1st Premolar Occlusal Marginal ridges are well-developed Lingual cusp is small Buccal cusp shows a heavy facial triangular ridge and a smaller lingual ridge Only premolars with a transverse ridge that does not cross the occlusal developmental groove Mandibular 2nd Premolar Eruption: 11 to 12 years Larger than the mandibular first premolar Buccal view resembles the first premolar, but with a shorter buccal cusp residing More efficient occlusion than the first molars Root does not bifurcate Mandibular 2nd Premolar Buccal Aspect Buccal cusp is shorter than the first premolar Mandibular 2nd Premolar Lingual Two common forms: EYE 29  o Three-cusp form: Mesiolingual and distolingual cusps present, with the mesiolingual being wider and longer, divided by a lingual groove o Two-cusp form: Single lingual lobe higher than the first premolar, with no groove Mandibular 2nd Premolar Mesial No mesiolingual developmental groove Mandibular 2nd Premolar Distal Distal marginal ridge is at a lower level than the mesial marginal ridge, allowing the occlusal surface to be visible Mandibular 2nd Premolar Occlusal Three-cusp form: Buccal cusp is largest, followed by the mesiolingual and distolingual cusps Lingual groove present Three developmental grooves: mesial, distal, and lingual Possible three pits: central, mesial, and distal Y-shaped outline Two-Cusp Mandibular 2nd Premolar Has only one well-developed lingual cusp U- or H-shaped occlusal outline No central pit No lingual groove U Molars Overview Molars are the largest and strongest teeth in the mouth. They are nonsuccedaneous or accessional teeth, meaning they do not replace any primary teeth. The first permanent molars erupt distal to the primary second molars and are usually the first permanent teeth to erupt. Mandibular teeth typically erupt slightly before maxillary teeth. (MOLARS CHAPTER 15) Cusp Anatomy  Light Each cusp is formed from a lobe. Major cusps are large and well-developed. Minor cusps are smaller, less developed, less functional, and not always present. Some molars may have a fifth lobe that develops into a supplementary cusp. (MOLARS CHAPTER 15) Maxillary 1st Molars Eruption: 6 to 7 years Largest teeth in the maxillary arch Three well-developed major cusps and one minor cusp (distolingual cusp, or tubercle, of 3 Carabelli) Two cusps on the buccal side, two on the lingual Three widely separated roots (MAXILLARY 1ST) Maxillary 1st Molar Buccal Aspect Four cusps visible: mesiobuccal (MB), distobuccal (DB), mesiolingual (ML), and distolingual (DL) Buccal developmental groove divides the buccal cusps Buccal pit with two small grooves Three roots visible: MB, DB, and lingual (MAX 1ST BUCCAL ASPECT) Maxillary 1st Molar Lingual Aspect ML cusp is the largest, MB cusp is the next largest, and DL cusp is the smallest and shortest of the functional cusps Lingual developmental groove (DL groove) Lingual root is usually the longest (MAX 1ST LINGUAL) Maxillary 1st Molar Mesial Aspect Clear profile of the cusp of Carabelli (MAX 1ST MESIAL) aug Maxillary 1st Molar Distal Aspect Distal marginal ridge is shorter and less prominent than the mesial More of the occlusal surface is visible Distobuccal root is the narrowest of the three (MAX 1ST DISTAL) Maxillary 1st Molar Occlusal Aspect Exit pedal  Oblique Wider lingually than buccally Ridge Central developmental pit in the central fossa Buccal developmental groove radiates from the central developmental pit Central developmental groove terminates at the mesial triangular fossa PELY Oblique ridge, a transverse ridge unique to maxillary molars, runs from the tip of the mesiolingual cusp to the tip of the distobuccal cusp (MAX 1ST OCCLUSAL) Maxillary 2nd Molars Eruption: 11 to 13 years Crowns are shorter and narrower than the first maxillary molars 9Eur No fifth lobe Distolingual cusp is less developed Roots are closer together and may be fused (MAX 2ND MOLARS) Maxillary 2nd Molar Buccal Aspect Buccal roots are the same length and closer together Crown is shorter and narrower than the maxillary first molar (MAX 2ND BUCCAL ASPECT) Maxillary 2nd Molar Lingual Aspect No cusp of Carabelli (MAX 2ND LINGUAL) Maxillary 2nd Molar Occlusal Aspect Mesiobuccal and mesiolingual cusps are as developed as the first molar Distobuccal cusp is slightly smaller, and the distolingual cusp is noticeably smaller More supplemental grooves and pits (MAX 2ND OCCLUSAL) Maxillary Molar Roots Trifurcated, with mesiobuccal, distobuccal, and lingual roots Roots connect to one root trunk, providing a sturdy anchor against displacement forces Lingual root is the longest, and the distobuccal root is the shortest All three roots are visible from the buccal view Bifurcation point is about 4 mm apical to the cervical line Pulp chamber and three main pulp canals, one for each root (MAXILLARY MOLAR ROOTS) Mandibular Molars Two roots: mesial and distal  Four major cusps; if a fifth cusp is present, it is a minor cusp Two buccal cusps are nearly equal in size, and two lingual cusps are almost equal in size Crown is broader mesiodistally than buccolingually (MANDIBULAR MOLARS IN GENERAL) Buccal Mandibular 1st Molars Fifaist Eruption: 6 years Usually the first permanent teeth to erupt Normally have five cusps: two buccal, two lingual (major), and one distal (minor) Largest teeth in the mandibular arch Generally have two roots: mesial and distal (MANDIBULAR 1ST MOLARS) Mandibular 1st Molar Buccal Aspect One distal and two buccal cusps Mesiobuccal cusp is the widest, and the distal cusp is the smallest Mesiobuccal and distobuccal cusps are approximately equal in height, separated by the mesiobuccal groove that ends in a pit (MAND 1ST BUCCAL ASPECT) v Mandibular 1st Molar Lingual Aspect Twats Mesiolingual and distolingual cusps are about equal in height, separated by the lingual developmental groove 30 Bifurcation of the roots begins with the bifurcation groove on the root trunk (MAND 1ST LINGUAL ASPECT) Mandibular 1st Molar Mesial Aspect Mesiolingual and mesiobuccal cusps, with the mesiolingual cusp being higher Mesial marginal ridge has a prominent crest, divided by the mesial marginal groove Buccal profile marked by the buccocervical ridge (MAND 1ST MESIAL ASPECT) Mandibular 1st Molar Distal Aspect Distolingual cusp is the largest, the distobuccal cusp is next, and the distal cusp is the smallest Distobuccal groove (MAND 1ST DISTAL) Mandibular 1st Molar Occlusal Aspect Five functional cusps  Three buccal cusps separated by two buccal grooves, and two lingual cusps separated by one lingual groove, forming a Y-shaped pattern Distobuccal cusp is the smallest major cusp Central developmental groove, mesiobuccal developmental groove, distobuccal pucca developmental groove, and lingual developmental groove (MAND 1ST OCCLUSAL) Mandibular 2nd Molars Eruption: 11 to 13 years Resemble the mandibular first molars buccally and lingually All four cusps are nearly equal in size Occlusally, the second molars have a more rectangular shape (MAND 2ND MOLARS) Mandibular 2nd Molar Buccal Aspect Similar to the first molar Crown is shorter mesiodistally Two equal-sized buccal cusps, separated by a single buccal groove (MAND 2ND BUCCAL ASPECT) 31 Mandibular 2nd Molar Lingual Aspect Mesiolingual and distolingual cusps are the same size, separated by the lingual groove, with a lingual pit (MAND 2ND LINGUAL) Mandibular 2nd Molar Occlusal Aspect Cusps are equal in size Developmental grooves traverse the occlusal surface in a cross pattern: buccal, lingual, and central developmental Three pits: mesial, distal, and central (MAND 2ND OCCLUSAL) Mandibular Molar Roots Two roots: mesial and distal Lingual Mesial root is longer, stronger, and curves mesially then turns distally Distal root is straight and may curve at the apical third (MANDIBULAR MOLAR ROOTS) Deciduous Teeth and Occlusion Review Primary Teeth Characteristics (Chapter 6) 4k pay yoga centE  20 total teeth 20 total deciduousteeth Universal numbering system A-T A T numbering Resemble permanent teeth but have: crowns spacesbetween Shaffer o Shorter crowns o Whiter appearance o Spaces between teeth that grow as the jaw grows o Allow room for tithing grows larger permanent teeth to erupt Allows forroom permanent for Eruption Dates (Chapter 16) teeth Mandibular teeth usually erupt first Mandibular Entire process takes about 2-3 years eye Central Incisors: 6-12 months Lateral Incisors: 7-13 months First Molars: 12-19 months Primary Canines: 16-22 months Second Molars: 21-33 months Tretption Leeward spaces Importance of Deciduous Teeth r Maintain space for permanent teeth Allow for bone growth of dental arches As bone grows, spaces develop between teeth: o Primate space: Between maxillary lateral incisor and canine, or between mandibular canine and first molar o Leeway spaces: Between first and second molars Leeway spaces allow extra margin of space for permanent canines, first and second premolars Resorption of deciduous roots helps guide eruption of permanent replacements If deciduous tooth is missing, permanent counterpart will not form If deciduous tooth is compromised, it may not leave enough room for permanent replacement Mixed DentitionBoth deciduous and permanent teeth are present Transition period when both primary and permanent teeth are present Occlusion Development (Chapter 6)  Begins with eruption of primary teeth Primary molars erupt around 16 months and establish intercuspation - the mesial-distal and buccal-lingual relationships that determine how maxillary and mandibular teeth touch, hit, and interlock Primary Occlusion Has three anteroposterior molar relationships called steps or planes: o Mesial step: Mandibular molars more mesial than maxillary counterparts o Flush terminal plane: Distal of deciduous second molars are even o Distal step x̅Diastemae: Maxillarymolars are moremesial I Spaces created when dental arches grow but teeth stay the same size Permanent Occlusion Permanent molars erupt and push the spaces between teeth closed Leeway space gained when permanent premolars replace deciduous ones Mandible continues to grow, usually ensuring a Class I relationship Malocclusions Deep bite: o Condyle head displaced distally o Posterior teeth don' t erupt enough o Hyperactive masticatory muscles o Condyle growth angle causes less mesial jaw development Horizontal alignment: o Tongue pushes teeth outward o Cheek/lip muscles keep teeth from going too far o Balance brings teeth into alignment o Disruption in balance leads to malocclusion Vertical alignment: o Mandibular posterior teeth crown tip lingually, roots tip laterally o Maxillary posterior teeth crown have slight buccal inclination, roots have slight lingual inclination o Anterior teeth have slight labial protrusion and lateral incline o All teeth have slight mesial inclination Centric Occlusion Position of mandible relative to maxillae Determined by how teeth fit together when jaws are closed  print Related to tooth occlusion, not muscle or bone Overjet, Overbite, and Crossbite 7 Overjet: Horizontal overlap of maxillary teeth over mandibular Overbite: Vertical overlap of maxillary anterior teeth over mandibular Crossbite: Mandibular teeth located facial to maxillary counterparts vet Occlusal Classifications Skeletal: re Edition nitrate o Class I: Maxilla and mandible in normal relationship o Class II: Mandible retruded, distal relationship with maxilla o Class III: Mandible start protruded, mesial relationship with maxilla Dental: Set forward o Molar Classification: ▪ Class I: Occlusal Relationship (Neutroclusion) ▪ Class II: Occlusal Relationship (Distoclusion) ▪ Class III: Occlusal Relationship (Mesioclusion) o Canine Classification: ▪ Class I: Mandibular canine distal within premolar width of maxillary ▪ Class II: Mandibular canine distal beyond premolar width of maxillary ▪ Class III: Mandibular canine mesial beyond premolar width of maxillary Other Occlusal Concepts Protrusion: Mandible moves forward, only anterior teeth should touch Premature contact: One tooth hits harder than others, can damage TMJ Ideal Occlusion CurveofSpee Occlusal plane almost flat with slight curve of Spee Tight proximal contacts, no spaces FEELSPACES No rotated teeth tigh Symmetric, well-formed arches Crowns tipped slightly mesially Maxillary third molar almost straight up and down Maxillary first molar is stolarized, tipped mesially  All 1st molars erupt at 6 years old All 1st premolars erupts at loliz yearsold All lateral incisors erupt at 719 yearsold All 2nd molars erupt at 1113 old All 2nd premolars erupt at years idk yeasold Erika 130ᵗʰ Eruptsat78y.o FistMolarsAll Erupts deciliters 179.0 Editio de nc Eat Erupts at oy.o.mn EEaD Fire 111791g yo 111387Ad in 9 Mars time at glio old Mandibular canines erupt years old canines erupt at 11112 years Maxillary Mandibular central incisors erupt at 6 yo at 7 84.0 Maxillary central incisors erupt