Dental Anatomy Lec 2-3 PDF

Course Title: Dental Anatomy I Course Code: OBI011 Topic of Lecture : -Tooth Anatomy and Surfaces. - Line and Point Angles. - Division into Thirds. Lecturer: Dr. Tamer Badawy Post : Lecturer P r o g r a m O F D e n t i s t r y...

Course Title: Dental Anatomy I Course Code: OBI011 Topic of Lecture : -Tooth Anatomy and Surfaces. - Line and Point Angles. - Division into Thirds. Lecturer: Dr. Tamer Badawy Post : Lecturer P r o g r a m O F D e n t i s t r y T h e F u t u r e S t a r t s H e r e F A L L 2 0 2 3 - 2 0 2 4 Upon successful completion of the course the students should be able to:  Tooth Anatomy Macro-Anatomy of the Tooth Each tooth has three anatomical parts: Enamel 1- Crown Cementum 2- The Neck: cervical line. 3- Root (s)  Micro-Anatomy of the Tooth The main structural elements of tooth include three calcified tissues (Enamel, Dentin and Cementum) and one delicate specialized connective tissue (Pulp).  Micro-Anatomy of the Tooth Enamel Dentin Pulp tissue -The main bulk (body) of tooth formed of Dentin -Dentin of crown (coronal D.), Dentin of root (Radicular D.) Alveolar - The dentin of the crown is covered by Enamel Bone - The dentin of the root is covered by Cementum - The central part of tooth ( inside dentin) there is pulp cavity which contain Pulp tissue - The root is embedded inside bony cavity ( formed of alveolar bone) called Socket -The root is surrounded by Periodontal Ligament which attach cementum to alveolar bone  Anatomy of the Pulp Cavity The pulp cavity is the cavity in the central portion of the tooth containing the pulp tissue. It is divided into the pulp chamber (in the crown) and the root canals (in the roots). 1.Pulp Chamber and Pulp Horns Each pulp chamber has a roof at its incisal or occlusal border often with projections called pulp horns, and the pulp chambers of multirooted teeth have a floor at the cervical portion with an opening (orifice) for each root canal. 2- Root canal(s) (pulp canal(s)) are the portions of the pulp cavity located within the root(s) of a tooth. Root canals connect to the pulp chamber through canal orifices on the floor of the pulp chamber, and pulp canals open to the outside of the tooth through openings called Apical Foramen. Pocket Dentistry.com  Junctions of tooth tissues Enamel 1- Cemento-enamel junction (CEJ): Cervical DEJ line CEJ Dentin 2- Dentino-enamel junction (DEJ): Pulp 3- Dentino-cemental junction (DCJ): DCJ Cementum  Anatomical and Clinical crown. Anatomical Crown Is that part of the tooth covered by enamel. Clinical Crown The clinical crown is the part of a tooth that is visible (seen) in the oral cavity and not covered by gingiva.  Anatomical and Clinical Crown Clinical Anatomical Crown Crown  Anatomical and Clinical Crown Clinical Clinical Clinical crown crown crown Anatomical crown Gingiva Gingiva Gingiva Is the part of a tooth that The part of the Gingival recession is visible in the tooth covered by oral cavity. enamel.  Clinical crown is that part of teeth seen in oral cavity (Part of the anatomical crown may be covered by gingiva.) Clinical crown may include all of the anatomical crown and part of the anatomical root. Part of Anatomical root Gingival Recession Anatomical crown Clinical crown  Anatomical and Clinical Root Anatomical root: It is the portion of the tooth that covered by cementum. Clinical root: It is that part of a tooth, which is under the gingiva, not exposed to the oral cavity and embedded in the jaw bones. The clinical root may be longer than the anatomical root. On newly erupted teeth, any part of the crown not exposed to the oral cavity is considered to be part of the clinical root. The clinical root may be shorter than the anatomical root In an elderly person due to gingival recession … because the portion of the root that is exposed to the oral cavity is considered part of the clinical crown.  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 crown Clinical 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. Trifurcation Bifurcation  Teeth may be divided according to the number of roots into: Single rooted teeth: Anterior teeth (incisors and canines). Premolars (except the upper first premolar). Muliple rooted teeth: Double rooted teeth: ( have two roots) Upper first premolars. May be lower canines. Lower molars. Triple rooted teeth: (have three roots) Upper molars. The undivided portion of the root is called Root Trunk. Tooth surfaces Each tooth has five surfaces Like a box with 4 sides and a roof.  OR BUCCAL LABIAL Towards the Towards the lip cheek FOR POSTERIOR ANTERIOR TEETH TEETH Lower first premolar LABIAL Surface PALATAL towards LINGUAL the palate towards the tongue (Upper teeth) OR (Lower teeth) Palatal surface Lingual surface  MESIAL DISTAL Towards the midline OR Away from the midline MIDLINE M D  INCISAL OR OCCLUSAL For Anterior Teeth For Posterior Teeth Line and Point Angles To determine a specific area of the crown. Line and point angles Line Point angle angle  Line angle It is formed by the junction of two surfaces and its name is derived from both surfaces. For example when mesial surface meets lingual surface the line angle is named as mesiolingual line angles.  Point angle It is formed by the junction of three surfaces and its name is derived from these surfaces. For example when mesial, lingual and incisal surfaces meet, the point angle is named as mesio-lingo-incisal point angle.  Anterior teeth 6 Line angles 4 Point angles 1- Mesio-labial L.A 1- Mesio-labio- incisal P.A 2- Mesio-lingual L.A 2- Mesio-linguo- incisal P.A 3- Disto-labial L.A 3- Disto-labio- incisal P.A 4- Disto-lingual L.A 4- Disto-linguo- incisal P.A 5- Labio-incisal L.A 6- Linguo-incisal L.A When we add incisal surface to the first four line angles of anterior teeth respectively you can get the 4 point angles.  Note: 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 existent.  Posterior teeth 8 Line angles 4 Point angles 1- Mesio-buccal L.A 1- Mesio-bucco- occlusal P.A 2- Mesio-lingual L.A 2- Mesio-linguo- occlusal P.A 3- Disto-buccal L.A 3- Disto-bucco- occlusal P.A 4- Disto-lingual L.A 4- Disto-linguo- occlusal P.A 5- Bucco-occlusal L.A 6- Linguo-occlusal L.A 7- Mesio-occlusal L.A 8- Disto-occlusal L.A When we add occlusal surface to the first four line angles of posterior teeth respectively you can get the 4 point angles. Division of Crown and Root into Thirds  Division into Thirds The crown surface can be divided both horizontally or vertically into three portions or thirds for purposes for description, location of anatomic landmarks and contact areas The root can be divided into thirds only horizontally. Remember: The root is also divided vertically into halves by the root axis line, such that the halves are either labial (buccal)/lingual or mesial/distal.  Division into Thirds Incisal &occlusal Middle Middle Buccal Distal Lingual Mesial Middle Cervical Labial View Proximal (Mesial or Distal) View  Cervical Middle Apical Distal half Labial View Mesial half Buccal half Lingual half Proximal (Mesial or Distal) View