Teeth Anatomy Introduction PDF

*The Dentitions Humans have two dentitions 1-The primary dentition 2-The permanent dentition  *The Dentitions 1-Tooth types 2-Dentition periods 1-The primary dentition: 6m to 6y 20 teeth. 10 maxillary and 10 mandibular. 2 incisors, 1 canine and 2 molars. The dental formula is: 2 1...

*The Dentitions Humans have two dentitions 1-The primary dentition 2-The permanent dentition  *The Dentitions 1-Tooth types 2-Dentition periods 1-The primary dentition: 6m to 6y 20 teeth. 10 maxillary and 10 mandibular. 2 incisors, 1 canine and 2 molars. The dental formula is: 2 1 2 I --- C ---- M ---- = 10 2 1 2 1- primary Dentition period ( From 6 months to 6 years) The only deciduous teeth are seen in the oral cavity 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 3- Secondary ( permanent ) Dentition period ( after 12 years of age ) The only permanent teeth are seen in the oral cavity.  Note The permanent molars are not preceded with deciduous teeth so they may be termed as non- succedaneous teeth. 2- Mixed Dentition period ( From 6 years to 12 years of age) Deciduous and permanent teeth are seen in the oral cavity  Mixed Deciduous Primary dentition Mixed dentition 6m-6y 6 y -12 y Shedding: It is the physiological loss of the Permanent deciduous teeth and their subsequent replacement by permanent teeth. Permanent dentition 12 y and up  X – Ray Showing 1- Primary dentition 2- Mixed dentition 6m-6y 6 y - 12 y 3- Permanent dentition 12 y and up  Tooth Anatomy 1- Macro-anatomy of the tooth Each tooth has three anatomical parts: Enamel 1- Crown Cementum 2- The Neck: cervical line. 3- Root (s)  Anatomical and clinical crown. Anatomical Clinical Crown Crown  Anatomical and clinical crown Clinical Clinical Anatomical crown crown crown Is the part of a tooth ☻The part that is visible in the of the tooth oral cavity above covered by the gum line. enamel. Clinical crown may include all of the anatomical crown and part of the root. Part of the anatomical crown may be covered by gingiva. Anatomical And Clinical Crown And Root Clinical Anatomical Crown Crown Clinical Root Anatomical Root Anatomical And Clinical Crown And Root Gingival Recession Gingival Recession Anatomical Clinical crown Crown Part of the Anatomical root Anatomical And Clinical Crown And Root C.C. CROWN A.C. ROOT C.R. A.R. Newly Erupted Teeth CROWN A.C. C.C ROOT A.R. C.R. Gingival Recession Teeth May Be Divided According To The Number Of Roots Single rooted teeth The undivided portion of the Multirooted teeth root is called: Root Trunk.  Teeth may be divided according to no. of roots into: Single rooted teeth Multirooted teeth  Junctions of tooth tissues There are three sites of Junction Enamel 1- Cemento-enamel junction DEJ (CEJ): Cervical line CEJ Dentin 2- Dentino-enamel junction Pulp (DEJ): 3- Dentino-cemental junction (DCJ): DCJ Cementum  3-Tooth designation 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 canine 5 Lower left second premolar 1 Lower right 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 D Upper right first deciduous molar lateral incisor Lower right second C Lower left deciduous canine E deciduous molar 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 15 Upper right second premolar 33 Lower left permanent canine Deciduous teeth 55 54 53 52 51 61 62 63 64 65 85 84 83 82 81 71 72 73 74 75 Upper right second Lower left lateral deciduous 55 deciduous molar 72 incisor 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 3-Tooth Orientational Terms: Each Tooth Has Five Surfaces Like A Box With 4 Sides And A Roof.  LABIAL OR BUCCAL Towards the Towards the lip cheek FOR POSTERIOR TEETH ANTERIOR TEETH PALATAL OR LINGUAL towards the towards the palate tongue MESIAL towards OR DISTAL away from the midline the midline MIDLINE  INCISAL OR OCCLUSAL For anterior teeth For posterior teeth To determine a specific area of the crown. Line and point angles Line Point angle angle Incisal edge Line And Point Angles Of The Anterior Teeth Line And Point Angles Of The Posterior Teeth  Note: Incisal ridge 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..  Horizontal division into thirds O O A A M M C C M M C C C C C M M M C A A I M I O: Occlusal M: middle C: cervical I : incisal A : apical  Vertical division into thirds M D M L M B P D L M M M D. Distal M. Mesial or Middle L. Lingual or labial B. Buccal  Division into thirds Incisal &occlusal Lingual Middle Buccal Distal Mesial Middle Middle Cervical  Middle Mesial Distal Middle Buccal Lingual Cervical Middle Apical Distal half Mesial half Buccal half Lingual half  Anatomical landmarks Lobe. A - Crown Elevations Tubercle. Ridge.  Lobe. It is one of the primary centers of calcification and growth formed during the crown development. There are three, four or five lobes The pulp chamber has pulp horns corresponding to these lobes.  Mamelons Lobe Cingulum Cusps  1. 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.  2.Cingulum: It is the enlargement or bulge on the cervical third of lingual surface of the crown in anterior teeth.  Cusp: Elevation of various shape & size present on **Incisal portion of canine. **The occlusal surface of post. Teeth It is formed of enamel, dentin& pulp Tubercle. It is a small elevation. It is produced by excessive formation of enamel. Tubercle differs from cusp as it is formed of enamel only while cusp is formed of pulp horn covered by dentin and enamel.  Ridge. It is a linear elevation on the different surfaces of the crown. Facial Lingual Occlusal A- Ridges on the facial surface (Labial and Buccal): Labial Ridge: Buccal Ridge: Cervical Ridge: Found on the labial Usually found on the It is found on the surfaces of buccal surfaces of the cervical one third of canines. premolars. the facial surfaces of all the teeth. Well developed in the (D) followed by (E).  B- Ridges on the lingual surface: 1.Incisal Ridge: 2.Cusp Ridge: 3.Lingual Ridge: 4.Marginal Ridge: IR C- Ridges on the occlusal surface of posterior teeth: 1 1.Marginal Ridges 2 2.Triangular Ridges: 1 2  Cusp Ridges Triangular R. DBC MBC Cusp Tip DMR MMR DLC MLC 3.Transverse 4.Oblique Ridge: (E67 may be D, 8)  Triangular Transverse Oblique All occlusal Upper molars surfaces of Lower premolar. posterior teeth.  B- Crown Depressions Linear depression Circumscribed depressions  Developmental grooves Denoting union of lobes Supplemental grooves 1- Linear depression They do not denote union of lobes. Fissures Incomplete enamel union 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.  Lingual fossa Fossa Mesial &distal fossa Central fossa Circumscribed depressions True Pits Faulty  Fossa Mesial &distal Lingual fossa Central fossa triangular fossae  pit True pit Faulty pit Present in the bottom of Usually develops as a central, mesial and distal result of incomplete triangular fossae. formation of enamel. At the end of buccal groove  *Dental anatomy terminology Each erupted tooth is surrounded and supported by the bone of the jaw. It’s called socket or alveolus The developing tooth present in a bony space and is called crypt. SOCKET: It is the bony space in the alveolar bone containing the roots of erupted tooth. It is the bony space in the alveolar bone CRYPT: containing the developing unerupted tooth.  OTHER TERMS SELF CLEANSING SURFACES: Facial Lingual Those surfaces of the teeth that are cleaned by the normal functional action of the tongue, lips, cheeks and lubricated by mouth fluids. Incisal Occlusal CALCIFICATION: The organic framework of a tooth becomes hard by depossition of calcium and phosphorous salts brought in by small blood vessels. Organic Hard Framework Tissues