Teeth Introduction PDF

Introduction and Nomenclature  Teeth and dental arches: The upper arch is called the 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. Each dental arch has a Midline that...

Introduction and Nomenclature  Teeth and dental arches: The upper arch is called the 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. Each dental arch has a Midline that divides it Into two equal right and left segments named As Quadrant. There are Four Quadrants in the oral cavity.. UPPER OR MAXILLARY TEETH LOWER OR MANDIBULAR TEETH In The Oral Cavity There Are Four 2 1 Classes Of Teeth That Includes: 1-Incisors: 3 - There is two incisors The central incisor and The lateral incisor. 4 2-Canines: -There is one canine in each quadrant. 3-Premolars: -There are two in each quadrant. First and second premolars. 4-Molars: -There are three in each quadrant. They are the first molar, the second molar and the third molar. -The incisors and canines are considered anterior teeth since they are closer to the midline. - Molars and premolars are considered posterior teeth since they are farther from the midline.  The Dentitions 1-The primary dentition: (deciduous ) This begins at 6 monthes and ends at 6 years. Why? The eruption of primary teeth begins at 6 monthes (for lower central incisor) and ends at 2 years(for the upper second deciduous molar). 20 teeth. 10 maxillary and 10 mandibular. 5 teeth are present in each quadrant. 2 incisors. 1 canine. and 2 molars. The dental formula is: 2 1 2 I --- C ---- M ---- = 10 2 1 2 2- The mixed dentition :(Transient phase) Begins at 6 years with eruption of the 1st permanent molar and ends at 12 years with shedding of the last deciduous tooth. The oral cavity contains both deciduous and permanent teeth. Ugly duckling stage Why? 3-The permanent dentition: (secondary, adult or succedaneous ) This begins at 12 years when all deciduous teeth are replaced by their permanent successors and persists for the whole life span of the teeth. 32 teeth, 16 maxillary and 16 mandibular. 8 teeth in each quadrant are Present. 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  X – Ray Showing 1- Primary dentition 2- Mixed dentition 6 m - 6 ys 6 ys - 12 ys 3- Permanent dentition 12 ys and up  Tooth Identification Systems 1) Palmer Notation System: It represents the four quadrants of the dentition as if you facing the patient. In upper right In upper left In lower right In lower left 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 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 Palmer Notation System 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 number 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 Deciduous teeth 55 54 53 52 51 61 62 63 64 65 85 84 83 82 81 71 72 73 74 75  3)The universal numbering system (American numbering system):. The number is always preceded by the sign # to designate that the system used is the 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 Deciduous teeth (1 – 20) 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 Deciduous teeth (A - T) A B C D E F G H I J T S R Q P O N M L K  Tooth Anatomy 1- Macro-anatomy of the tooth Each tooth has three anatomical parts: Enamel I.Crown Cementum II.The Neck: cervical line or cemento-enamel junction (CEJ). II.Root (s) Anatomical And Clinical Crown And Root Gingival Gingival Recession Recession Anatomical crown Clinical Crown Part of the Anatomical root Tooth Anatomy 2- Micro-anatomy of the tooth -Three calcified tissues: Enamel Dentin Cementum + One soft specialized connective tissue: Pulp.  SUMMARY Enamel: Coveres the anatomical crown, Most Mineralized, Yellowish White. Cementum: Coveres the anatomical root, Medium For The Attachment, Dull Yellow, Thickness. Dentin: Makes the main bulk of the tooth.Surrounds The Pulp Cavities, Underlying The Enamel and The Cementum, Yellow. Pulp: Housed In The Pulp Cavity, Soft Tissue, Supply.  Anatomy Of The Pulp Cavity Consists Of Two Parts 1 - Pulp chamber Pulp + pulp horns Horn 2 - Root canal (s) + apical foramen + accessory canals  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: - 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. Tooth Surfaces  Facial surfaces LABIAL OR BUCCAL TOWARDS TOWARDS THE LIP THE CHEEK FOR FOR ANTERIOR POSTERIOR TEETH TEETH  Lingual surfaces PALATAL OR LINGUAL TOWARDS TOWARDS THE PALATE THE TONGUE FOR MAXILLARY FOR MANDIBULAR TEETH TEETH  Proximal surfaces & TOWARDS THE MIDLINE AWAY FROM THE MIDLINE FOR ALL THE TEETH  Occluding surfaces INCISAL OR OCCLUSAL FOR ANTERIOR TEETH FOR POSTERIOR TEETH  Division Into Thirds For descriptive purposes ( to locate the anatomical landmarks ): - Crown surfaces could be divided horizontally or vertically into three portions or thirds, - The root could be divided into thirds horizontally, while vertically into halves by the root axis line { labial (buccal) & lingual and/or mesial & distal }. Division Into Thirds  Line And Point Angles Line Point angle angle  Line And Point Angles Line angle: It is formed by the junction of two surfaces and its name is derived from both surfaces Point angle: It is formed by the junction of three surfaces and its name is derived from these surfaces. Note: The anterior teeth have fewer line angles because the meeting of the mesial and distal line surfaces with incisal ridge are rounded , so the mesio-incisal and disto-incisal line angles are practically not exist.. Anatomical Landmarks Of The Crown A - Crown Elevations (1) Lobe. It is one of the primary centers of calcification and growth formed during the crown development. Each tooth begins to develop from four lobes or more. The pulp chamber has pulp horns corresponding to these lobes. PULP THE MATURE FORMS HORN OF LOBES ARE: 1. Mamelones 2.Cingulum 3.Cusps 2. Mamelones: They are three small round projections of enamel present in the incisal third of newly erupted incisors. After normal use, eventually the mamelones wear down into a flat edge. 3.Cingulum: It is the enlargement or bulge on the cervical third of lingual surface of the crown in anterior teeth (incisors and canines). It is also called the lingo- cervical ridge 4.Cusps: They are pyramidal projections on the incisal portion of the canine and on the occlusal surfaces of the premolars and molars teeth. 5-Tubercle: It is a small elevation due to excessive formation of enamel. Tubercle is noticed at the palatal surface of E & 6 It differs from cusp as it is formed of enamel only while cusp is formed of pulp horn covered by dentin and enamel. B ENAMEL DENTI D M N PULP HORN P Cusp Tubercle  (6) Ridge: It is a linear elevation on the different surfaces of the crown. a-Labial Ridge: b-Buccal Ridge: c-Cervical Ridge: Found on the Usually found on It is found on the labial surfaces the buccal surfaces cervical one third of of canines. of the premolars. the facial surfaces of all the teeth.  d-Incisal Ridge: e-Cusp Ridge: Cusp Slopes Or Cusp Arms f-Lingual Ridge: g-Marginal Ridge: IR NOTE: Usually distal cusp slope is longer than mesial cusp slope in all teeth except C and 4 where the mesial cusp slope is longer than the distal  1 g-Marginal Ridges 2 h-Triangular Ridges: All posterior tooth cusps have a triangular ridge, except the mesiolingual cusp on maxillary molars which has two triangular ridges 1 2  i-Transverse Ridge: Found in lower premolars j-Oblique Ridge: (E67 may be D, 8) Remember that all teeth either anterior or posterior have cervical ridge and two marginal ridges (mesial and distal one).  B- Crown Depression: 1- DEVELOPMENTAL GROOVE: It is narrow, shallow and sharply defined short or long, denoting union of primary lobes.  2- SUPPLEMENTAL GROOVES: They are small, irregularly placed auxiliary grooves. Branches from developmental grooves. Found usually on occlusal surfaces. They do not denote union of primary lobes. The third molars followed by second permanent molars are characterized by high number of supplemental grooves. 8 8  3- FISSURE: It is found in the bottom of developmental groove. Results from incomplete union of the primary lobes. Cusp It isCusp tipin enamel. a fault tip Developmen tal groove Ename lDenti Fissur n e SULCUS: It is a broad depression or valley on the occlusal surfaces of posterior teeth. Its inclines meet in a developmental groove and extend to the cusp tips. 4- FOSSA: It is a small depression or concavity. Found in both anterior and posterior teeth. Its name is derived from its place: a- LINGUAL FOSSA: Found on the lingual surfaces of anterior teeth. LF b- MESIAL AND DISTAL TRIANGULAR FOSSAE: Found on the occlusal surfaces of posterior teeth mesial and distal to the marginal ridges. DTF MTF DM MM R R c- CENTRAL FOSSA: Found on occlusal surfaces of molars. They are formed by the converging of ridges terminating at a central point where there is the junction of grooves. CF CP  2- PITS: a- TRUE PITS: These are small pinpoint c. depression. Present at the p. junction / or at the ends of the developmental grooves. They may be found at the bottom d. p. of the central fossa (central pit) or at the bottom of the mesial and distal triangular fossae m. (mesial and distal pits). p. b- FAULT PIT incomplete formation of enamel. It is located at the end of the buccal developmental grooves of the lower molars or palatal developmental p.p b.p grooves of the upper molars... SOCKET: It is the bony space in the alveolar bone containing the roots of erupted tooth. CRYPT: It is the bony space in the alveolar bone containing the developing unerupted tooth.