Dental Anatomy Lec 4 PDF

Course Title: Dental Anatomy I Course Code: BDS021 Topic of Lecture : -Crown Depressions - Life History of the Tooth Lecturer: Dr. Tamer Abdelhady Badawy Post : Lecturer P r o g r a m O F D e n t i s t r y T h e...

Course Title: Dental Anatomy I Course Code: BDS021 Topic of Lecture : -Crown Depressions - Life History of the Tooth Lecturer: Dr. Tamer Abdelhady 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 4 - 2 0 2 5 By the end of this lecture, the student will be able to:  B- Crown Depressions 1-Linear Depressions 2-Circumscribed Depressions 3- Sulcus  A-Developmental grooves Denoting union of lobes 1- Linear B-Supplemental grooves Depressions They do not denote union of lobes. Fissure Sealant C-Fissures Incomplete enamel union Developmental Groove Fissure Dental Caries always begin in deep fissures Developmental Groove: Shallow, linear depression represents the site of union of primary lobes. Grooves are found on the occlusal surfaces Of posterior teeth and may extend to the buccal and lingual surfaces. They are named according to location.Grooves act as spillways for cusps during lateral and protrusive jaw motions. Supplemental Groove: They are short, irregular linear depression found usually on the occlusal surface and do not represent union of lobes. They are auxilliary grooves radiating from the developmental grooves. They can be named according to the parts of the tooth on which they are found (mesiobuccal, distolingual…etc supplemental grooves). The third (8) followed by the second permanent Molars (7) are characterized by numerous supplemental grooves giving their occlusal surfaces a WRINKLED appearance. Fissure: It is a linear depression found on the bottom of developmental groove as a result of incomplete union of Primary lobes. It is a fault in enamel. Dental caries often begins in a deep fissure.  2-Circumscribed Depressions A-Fossa B-Pits  A-Fossa -It is a small depression found in both anterior and posterior teeth. -It is named according to Location or Shape: A- Lingual Fossa: Found on the lingual surfaces of anterior teeth. B- Central Fossa: Found on the occlusal surfaces of molars. C- Mesial and Distal Triangular Fossa: Found on the occlusal surfaces of posterior teeth, mesial and distal to marginal ridges of posterior teeth.  Lingual fossa A-Fossa Mesial &distal fossae Lingual Central fossa fossa Circumscribed depressions True B-Pits Faulty  A-Fossa Mesial &distal triangular Lingual fossa Central fossa fossae Lingual fossa Found on the occlusal surfaces of Found on occlusal surfaces posterior teeth Found on the lingual surfaces of of molars anterior teeth  B-Pits These are small pinpoint depression present at the junction or at the ends of the developmental grooves. True Pits are found at the bottom of the central fossa (central pit) or at the bottom of the mesial and distal triangular fossae (mesial and distal pits). Faulty pits usually develop as a result of incomplete formation of enamel. It is located at the end of the buccal developmental grooves ( D.G) of the lower molars (Buccal Pit) or palatal D.G of the upper molars (Palatal Pit).  B-Pit True pit Faulty pit Present in the bottom of central, mesial and distal triangular fossae. Usually develops as a result of incomplete formation of ( central,mesial & distal pit) enamel. 3-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. SOCKET (Alveolus): It is the Bony space in the alveolar bone containing the roots of erupted tooth. Alveoli It is the Bony space in the alveolar bone containing the CRYPT: crown of 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 deposition of calcium and phosphorous crystals. Organic Hard Tissues Framework Quiz1 Sample Question Identify line and point angles Life history of the tooth Prof Samah Mehanny Edited by: Dr. Tamer Badawy  1-Soft growth stage: dental organ appearance. Tooth germ The deciduous and most of permanent teeth start their 1-Dental development inside the jaw (Enamel) organ before birth. Tooth germ is formed of soft tissue and does not appear in the x-ray films 2-Dental papilla 3-Dental sac 2-Calcification: Calcification of the hard dental tissues (enamel, dentin and cementum) occurred by specialized cells.  3-Eruption: -The eruption of the mandibular tooth usually precedes the maxillary tooth. -The teeth in both sides of the jaw erupt at the same time. -Teeth erupt in girls earlier than boys. - The tooth erupts in the oral cavity when its crown is completely formed as well as cervical one third of the root. Chronology of a tooth: is the order in which a series of events happened Enamel organ appearance. (soft growth stage) Beginning of calcification.  Crown completed. Eruption. Root completed.  4 - Attrition: Is physiological loss of the hard dental structure due to the continuous friction of the teeth (Tooth-Tooth contact) with each other during mastication 5- Shedding of the deciduous teeth: Is the physiological loss of the deciduous teeth after their roots are subjected to RESORPTION and their subsequent replacement by their permanent successors.