Dental Anatomy Introduction PDF

INTRODUCTION Dental Anatomy Includes: 1- Structures of the oral cavity. 2- Overview of the dentitions 3- The relationship of the teeth to each other. 1- Structures of the oral cavity. 1-Lips 2-Gingiva 3-Cheek 4-Tongue 5-Floor of the mouth 6-Roof of the mouth 7- Teeth ...

INTRODUCTION Dental Anatomy Includes: 1- Structures of the oral cavity. 2- Overview of the dentitions 3- The relationship of the teeth to each other. 1- Structures of the oral cavity. 1-Lips 2-Gingiva 3-Cheek 4-Tongue 5-Floor of the mouth 6-Roof of the mouth 7- Teeth  1- Lips Two Lips Upper Lip and Lower Lip. The Corner of the mouth where the two lips meet is called Commissure Two Grooves are distinguished around lips. *Nasolabial groove *Labiomental groove.  2- Gingiva It is the tissue surrounds the cervical part of teeth.  3- Cheeks Linea alba buccalis Parotid papilla  4- Tongue The tongue is a broad flat organ composed of muscles and glands. It rests in the floor of the mouth. It is the principle organ of taste and is most important in speech,mastication and swallowing.  5- Floor of the mouth It is shiny and some large blood vessels may be seen near the surface. Beneath the tongue there are two bilateral bulges caused by the presence of large salivary glands.  6- Roof of the mouth Its anterior part is called hard palate. Its posterior part is called soft palate which ends by a small fleshy structure named uvula  7- Teeth Teeth are arranged in upper and lower dental arches. The upper arch is called Maxilla The teeth in this arch are called upper or maxillary teeth The lower arch is called the Mandible The teeth in this arch are called lower or mandibular teeth. Midline divides each arch into two equal right and left halves. There are 4 Quadrants in the oral cavity. There are Four types of teeth : 1-Incisors: There are two incisors, central incisor and lateral incisor. 2- Canines: There is one canine in each quadrant. Incisors and canines are considered Anterior Teeth.  3-Premolars There are two in each quadrant. First and second premolars. 4-Molars: There are three in each quadrant. First, second and third molars. Premolars and molars are considered Posterior teeth  Function Of Teeth 1- Mastication  Functions Of Teeth 1- Mastication: It is the most important function of the teeth. The teeth are designed to perform this function. Incisors Canine Premolars Molars Chisel like Wedge like At least two Multiple projections Cutting or Cutting and projections (cusps) incising tearing (cusps). Grinding Tearing and grinding 2- Appearance Nice smile Bad smile 2- Appearance: - Well arranged clean teeth with proper alignment give nice appearance to the face. – Teeth give support to the facial expressions. 3- Speech: Teeth are important for clear pronunciation and for production of sound. 4- Growth of jaws: The teeth play a role in the growth of the jaws in some periods of life. Types of Dentitions Humans have two dentitions 1-The primary dentition 2-The permanent dentition The mixed dentition *The Dentitions 1-Teeth types 2-Dentition periods 1-The primary dentition (deciduous, predecessors): 6m to 6y 20 teeth. 10 maxillary and 10 mandibular. 2 incisors, 1 canine and 2 molars. The dental formula (no and types of teeth) is: 2 1 2 I --- C ---- M ---- = 10 2 1 2  2-The permanent dentition: after 12 y (secondary, adult or succedaneous ) 32 teeth, 16 maxillary and 16 mandibular. 2 incisors, 1 canine, 2 premolars and 3 molars. The dental formula is : 2 1 2 3 I ---- C ---- PM --- M ---- = 16 2 1 2 3  Note The permanent molars are not preceded with deciduous teeth so they may be termed as non- succedaneous teeth.  The mixed dentition: 6y to 12 y Surfaces of Teeth  Each tooth has 5 surfaces like a box with 4 sides and a roof. MASTICATORY LINGUAL DISTAL MESIAL FACIAL  FACIAL LABIAL BUCCAL Towards lip Towards cheek ANTERIOR POSTERIOR TEETH TEETH FACIAL  LINGUAL PALATAL LINGUAL (Upper) (Lower) Towards Towards palate tongue LINGUAL  PROXIMAL MESIAL towards DISTAL away from midline midline DISTAL MESIAL  MIDLINE M M D D  MASTICATORY INCISAL OCCLUSAL Masticatory For anterior teeth For posterior teeth Mention the surfaces  Line and point angles Line Point angle angle Labial Distal Buccal Distal  NOTE  In anterior teeth, mesio-incisal & disto- incisal line angles don’t exist.  Why?  The meeting of the mesial and distal surfaces with incisal ridge are rounded. Labial Distal Buccal Distal Labial 10 Buccal Division of tooth surfaces Incisal & occlusal Middle Lingual Buccal Mesial Middle Distal Middle Cervical  Mesial Middle Distal Lingual Buccal Middle Cervical Middle Apical Distal half Mesial half Lingual half Buccal half  Tooth identification system To identify a specific tooth should mention: 1-Types of dentition (permanent or deciduous) 2-The arch (upper or lower) 3-The quadrant (right or left) 4-The name of the tooth  Tooth identification system 1) Palmer Notation System: The permanent teeth are numbered from 1-8 on each side from the midline. Upper right Upper left 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 Lower right Lower left 8 Upper right third molar 3 Upper left per. canine 5 Lower left second premolar 1 Lower right per. central incisor The deciduous teeth are lettered from A-E on each side from the midline. Upper right Upper left E D C B A A B C D E E D C B A A B C D E Lower right Lower left B Upper left deciduous lateral D Upper right first deciduous molar incisor Lower right second deciduous C Lower left deciduous canine E molar  1-Palmer Notation System For permanent teeth Right Left 8-1 3 2 1 1 2 3 1-8 4 4 5 5 6 6 7 7 8 8 8 7 6 8-1 5 1-8 4 3 1 2 Palmer Notation System A For primary teeth B C E-A D A-E E E-A A-E  2- The international numbering system (The two digit system) The teeth are designed by using two-digit systems: a. The first digit of the code is located at the left side of the numb and indicates the quadrant. In the permanent dentition. In the deciduous dentition. U.R. 1 2 U.L. U.R. 5 6 U.L L.R. 4 3 L. L. L.R. 8 7 L.L. b. The second digit is located at the right side of the number and indicates the number of the tooth in the quadrant. ****The two digits should be pronounced separately.  Permanent teeth 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 15 Upper right second premolar 33 Lower left per. canine Deciduous teeth 55 54 53 52 51 61 62 63 64 65 85 84 83 82 81 71 72 73 74 75 55 Upper right second deciduous 72 Lower left lateral deciduous incisor molar  For permanent Teeth 12 11 21 22 13 23 14 24 First Digit = quadrant 15 25 16 26 17 27 Second Digit = tooth number 18 28 38 48 1 2 47 37 36 46 35 4 3 45 44 34 43 33 42 41 31 32  For Primary Teeth 51 61 52 62 53 63 54 64 First Digit = quadrant Second Digit = tooth number 55 5 6 65 8 7 85 75 5 6 84 8 7 74 83 73 82 81 71 72  3)The universal numbering system (American numbering system): The number is always preceded by the sign # to designate that the system is used for universal system. Permanent teeth (1 – 32) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 #28 Lower right first premolar #16 Upper left third molar  Deciduous teeth (1 – 20) The number is preceded by d # 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 Or (A - T) The letter is preceded by # only A B C D E F G H I J T S R Q P O N M L K d# 14 Lower left deciduous #B Upper right deciduous lateral incisor first molar  Universal system for Permanent Teeth  Universal System for Primary Teeth Anatomical landmarks of Tooth crown Lobe Crown Elevations Tubercle Ridge  Lobe One of the primary centers of calcification and growth formed during crown development.  Each tooth develops from 4 lobes or more.  Molars: 4 lobes (2Premolars:  Anteriors: Buccal 4 lobes & 2 Lingual) (3(3Buccal Labial & 1 Lingual) Two lobes may be found in:  Peg-shaped upper lateral incisor.  Supernumerary teeth.  Mamelons 1.Lobe Cingulum Mature form Cusps  A. Mamelons Three small round projections of enamel present in Pulp the chamber incisal third of of upper newly erupted incisors. incisors has 3 pulp horns corresponding After normal use, to these they 3 eventually wear down into a labial flat lobes (mamelons). edge.  B. Cingulum It is a rounded prominence or bulge on the cervical third of the lingual surface of the crown of anterior teeth.  C. Cusp  An elevation nearly pyramidal in shape.  Formed of enamel, dentin & pulp. Found on occlusal surface of posterior teeth & incisal portion of canine.  2.Tubercle  It is a small elevation, produced by excessive formation of enamel ONLY.  CUSP TUBERCLE  3.Ridge A linear elevation on the different surfaces of the crown. 1.Labial ridge In canines 2. Buccal ridge In premolars 3.Lingual ridge In canines 4- Incisal ridge In all anterior teeth. 5.Cervical ridge At cervical 1/3 of facial surfaces of all teeth. 6.Marginal ridge In all anterior & posterior teeth. 7. Triangular ridge In all posterior teeth. 8. Cusp ridge In all posterior teeth. 9.Transverse ridge In lower premolars. 10.Oblique ridge In upper molars. Mention the name of the decayed part.  SURFACE ANATOMY OF PERMANENT ANTERIOR TEETH  Intended Learning Outcomes (ILO’s) a- Knowledge and understanding By the end of the course, the student should be able to: 4. Define the anatomical landmarks of the crowns of human teeth. 5. Identify and describe the morphological features as well as the pulp cavities of anterior and premolar human teeth, in addition to memorizing their chronologies. b- Intellectual skills: By the end of the course, the student should be able to: b.2. Distinguish any morphological abnormalities in human teeth.  Anterior teeth They are divided into: Incisors And Canines  Incisors There are four maxillary and mandibular incisors. ♥ Two central incisors contact with each other in the midline (mesially) and with the lateral incisors distally. ♥ Two lateral incisors contact with the central incisor mesially and with the canine distally.  Functions Mastication (incising for incisors and tearing for canine), Esthetic Speaking (Pronunciation) Growth of the jaws.  Number of lobes: All anterior teeth (incisors and canines) formed of four lobes, three labially and one lingually. 4 4 1 2 3 1 2 3  Chronology Enamel organ appearance.  5 m.i.u Beginning of calcification. 3-4 m.  Crown completed. 4-5y Eruption. 7-8 y Root completed. 10-11y  Beginning Crown Eruption Root of calc. completed completed (m) (Y) (Y) (Y) 1 7-8 3-4 1 6-7 2 10-12 8-9 2 3-4 7-8 3 11-12 4-5 3 9-10  Permanent maxillary central incisor  1 Maxillary central incisor is the first tooth from the midline. The two upper centrals are the widest of all the anterior teeth. The crown is the longest of all human teeth. All teeth have 5 aspects 1 Labial Lingual Mesial Distal Incisal  For easy teeth description We have to speak about : Geometric outline of the crown. Outlines of the crown and root. Straight Convex Concave Surface anatomy of the crown and root (anatomical landmarks). Cervical line. Root.  Geometric outline of the crown Facial and lingual aspects have trapezoidal outline. Smallest uneven side cervically.  Facial and lingual outlines of the crown Cervical outline (convex root wise) Distal outline Mesial outline (more convex) (convex) D Contact area M Contact area At the junction of M& I 1\ 3. In the I 1\ 3. Rounded Incisal (straight and may Sharp mesioincisal distoincisal angle have mamelons) angle Newly erupted teeth 1 1 2 3  Outlines of the root The mesial and distal outline of the root tapered to a blunt apex The apex is centralized on the long axis so extraction could be done by rotation movement  Surface anatomy of the crown and root. Labial aspect Elevations: The crown surface is smooth and convex with maximum convexity at the cervical third (cervical ridge) Depressions: Shallow developmental grooves could be seen separating mamelons. The root surface is smooth and convex  Lingual aspect Elevations: Marginal ridges (mesial and distal) Cingulum (cervically) Incisal ridge cingulum Depressions: Lingual fossa ( it lies between the previous elevations). Incisal Marginal ridge ridges This convergence of the teeth is to accommodate the larger arch size facially than lingually  Geometric outline of the crown Proximal (mesial and distal) aspects have triangular outline Base cervically. Apex incisally.  Mesial and distal Outlines It’s Triangular and formed of Labial outline: convex with maximum convixity at the cervical third which represent (cervical ridge). Lingual outline: Convex incisally which represent (incisal ridge). Concave at the middle which represent (lingual fossa). Convex cervically which represent (cingulum). Cervical outline: Curves incisally.  M D The crown has smooth convex proximal surfaces. Contact areas: Near the junction of I & M 1\ 3. Near the MI angle. Cervical line: Curved incisally, Its curvature The curvature is shallower than is greater than any other mesially. teeth in the mouth.  Outlines of the root The outlines tapered from the cervical line to a blunt rounded apex They have convex smooth surfaces.  Incisal aspect Outline and surface anatomy The outline is triangular in shape. The base is placed labially and apex lingually. The mesiodistal dimension (width) is greater than the labiolingual The crown is tapered lingually. Note: The elevations and depressions in the crown lingually and labially appeared in this aspect. Labial Lingual Mesial Distal Incisal  Number of lobes: All anterior teeth (incisors and canines) formed of four lobes, three labially and one lingually. 4 3 1 common situation is to find upper lateral incisors have pointed forms (peg-shaped lateral incisors) with a different number of lobes. In some individuals, the lateral incisors are missing entirely. The lateral incisor is smaller in all dimensions than the central incisor. 1 2  1 2 Labial aspect D M D M sharp M I angle. rounded M I angle. rounded D I angle. more rounded D I angle. Incisal outline Straight Rounded 1 2 Newly erupted tooth has The mamelons are mamelons. less pronounced. 1 2 Labial surface: Convex or slightly flat. More convex. Labial D G. Less prominent. 1 2 The mesial and distal The mesial and distal outline of the root tapered outline of the root tapered to a blunt apex to a pointed apex The apex centralized on The apex directed distally the long axis  Lingual aspect Elevations: Marginal ridges (mesial and distal) Cingulum Marginal Cingulum (cervically) ridges Incisal ridge Depressions: Incisal ridge Lingual fossa, more concave and circumscribed Note: Lingual pit could be found in the 2 and Notice that all elevations are well developed than 1. 1 1 2 3  1 2 Mesial aspect Lb Lg Lb Lg The crown long and thick labiolingually. Shorter and thinner. The mesial surface is flat The surface is flatter. Contact area at I 1\3 near the M I angle. Near or at the junction of I & M 1\3 No developmental depression in root. There is shallow developmental depression in the root. Mesial cervical line : Curves incisally, Its convex incisally (less than central). curvature is greater than any other teeth in the mouth.  1 2 Distal aspect C.A. at the junction of I & M 1\3 In the middle third of the crown. No developmental groove. There is developmental groove. The distal marginal ridge is Distal marginal ridge is irregular. regular.  Incisal aspect 1 2 Wide M D. Smaller in size. Labial and lingual O.L. Labial and lingual O.L. are flat and broad. are more rounded. When palatal pit is present; it is located in the depth of the lingual fossa  Pulp cavity. Pulp cavity is formed of: Pulp chamber that is present in the crown. Its outline follows the outline of the crown. In young teeth, it has pulp horns related to each mamelon 2 Showed similar but smaller pulp cavity. MD LL Pulp chamber in 2 has one rounded or two less sharp pulp horns (M & D). Root canal is present in the root and follows its outline. In each of the incisors there is only one root canal. The root canal ends in an apical foramen