Oral Anatomy PDF

Introduction to Dental Anatomy Jeorge V. Junio, DMD, MS Dent Educ Dental Anatomy } a field of anatomy dedicated to the study of human tooth structures. } The development, appearance, and classification of teeth fall within its purview. } Dental Anatomy is al...

Introduction to Dental Anatomy Jeorge V. Junio, DMD, MS Dent Educ Dental Anatomy } a field of anatomy dedicated to the study of human tooth structures. } The development, appearance, and classification of teeth fall within its purview. } Dental Anatomy is also a taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment. Dental Anatomy De ned as the study of the development, morphology, function, and identity of each of the teeth in the human dentitions, as well as the way in which the teeth relate in shape, form, structure, color, and function to the other teeth in the same dental arch and to the teeth in the opposing arch fi Dental Anatomy, Physiology and Occlusion Provides one of the basic components of the skills needed to practice all phases of Dentistry Application of Dental Anatomy to Clinical Practice Human Dentition Heterodont ➡ Greek meaning “different teeth “ Diphyodont ➡ two sets of teeth in a life time Formation of the Dentitions (Overview) Diphyodont two sets of teeth in a life time 1. Temporary Teeth 2. Permanent Teeth Formation of the Dentitions (Overview) 1. Temporary Teeth also known Deciduous Teeth , Primary Teeth, Baby Teeth or Milk Teeth begins to form at about 14 weeks in utero & completed post natally about 3 years of age begins to emerge at the mean age of 6 mts, and the last emerge at a mean age of 28 +- 4 months (3 yrs old) Formation of the Dentitions (Overview) 2. Permanent Teeth also known Secondary Dentition to erupt at a mean age of 6yo. marks the Transition Stage Transition Stage Mixed Dentition Stage or Ugly Duckling Stage a stage at which there is a mixture of deciduous and succedaneous teeth present. Transition Period: 6-12 years of age Dif cult time for a child ➡ Habits, missing teeth, teeth of different colors and hues, crowding and malpositioning are evident fi Two Types of Permanent Teeth 1. Succedaneous Teeth 2. Non-Succedaneous Teeth Two Types of Permanent Teeth 1. Succedaneous Teeth Permanent Teeth that replaces the deciduous teeth in the dental arch Central Incisors, Lateral Incisors, Canines, Premolars Two Types of Permanent Teeth 2. Non - Succedaneous Teeth or Accessional Dentition / Teeth Maxillary and Mandibular 1st, 2nd and 3rd Molar The Deciduous Teeth ⦿ 20 Deciduous Teeth a. 8 incisors b. 4 canines c. 8 molars The Deciduous Teeth Upper/Maxillary Anterior Teeth Central incisor Lateral incisor Canine The Deciduous Teeth Lower/Mandibular Anterior Teeth Central incisor Lateral incisor Canine The Deciduous Teeth Lower/Mandibular Posterior Teeth 2nd Molar 1st Molar Eruption Sequence of Deciduous Teeth The Permanent Teeth ⦿ The permanent teeth to appear in the oral cavity by the age of 6 yrs old is mandibular first permanent molar. ⦿ There are 32 Permanent Teeth a. 8 incisors b. 4 canine c. 8 premolars d. 12 molars Upper/Maxillary Anterior Teeth Central Incisor Canine Lateral Incisor Upper/Mandibular Anterior Teeth Central Incisor Canine Lateral Incisor Lower/Mandibular Teeth 2nd Molar 1st Molar 2nd Premolar 1st Premolar Canine Lateral Incisor Central Incisor Upper/Maxillary Teeth Central Incisor Lateral Incisor Canine 1st Premolar 2nd Premolar 1st Molar 2nd Molar  Eruption Sequence of Permanent Teeth Maxillary Teeth Mandibular Teeth Types of Teeth Based on Location 1. Anterior Teeth - Front Teeth - Central & Lateral Incisors and Canines 2. Posterior Teeth - Back Teeth - Premolars and Molars Types of Teeth Based on Location Incisors ⦿ are the squarish, sharp-edged teeth at the front and middle of the mouth. There are four on the bottom and four on the top. Types of Teeth Based on Location Canines / Cuspid ⦿ To the sides of the incisors are the long, sharp canines, two on the bottom and two on the top. Types of Teeth Based on Location Premolars / Bicuspids ⦿ Behind the canines ⦿ There are two sets, or a total of four premolars, two behind each of the canines on the bottom and two behind each canine on the top. ⦿ These teeth are absent in the primary set. Types of Teeth Based on Location Molars ⦿ situated behind the premolars, have points and grooves. ⦿ There are 12 molars in the adult mouth, three sets in each jaw called first, second, and third molars. ⦿ The third molars are called Wisdom Teeth. Types of Teeth Based on Location ⦿ Wisdom teeth get their name because, as the last teeth to erupt, they break through when a person is becoming an adult and is supposedly wiser. ⦿ Wisdom teeth are not essential today, but some people believe they evolved thousands of years ago when human diets consisted of mostly raw foods that required extra chewing power. TEETH Development of Teeth ⦿ The tooth is a structure formed by the combination of different kinds of tissues. ⦿ Each tissue is formed by different cell types that work in a well co-ordinated and co-dependent way. ⦿ The tooth goes through the following phases of development, named based on the peculiarities of the Stages of Tooth Development. a. Bud stage b. Cap stage c. Bell stage d. Maturation The different tissues with their respective cells of formation are as follows; ⦿ Enamel - Ameloblasts ⦿ Dentin - Odontoblasts ⦿ Dental Pulp - Mesenchymal Cells ⦿ The Root is formed by a combination of the dentin and cementum formed by Odontoblasts and Cementocytes respectively. The tooth development is completed after its the eruption. Structure of the Teeth ⦿ The tooth is a mineralized entity. ⦿ It can be divide into Two Portions; 1. Coronal or the Crown Structure ➡ is the visible portion of the tooth 2. Radicular or the Root Portion ➡ is covered by the gingival or the gums. Structure of the Teeth ⦿ Enamel Junction/CEJ - Also known as Cervical Line - “Neck” portion of a tooth ๏ CEJ Configurations: Structure of the Teeth ⦿ The difference in crown and root of the tooth lies in the fact that enamel is the outer covering of the crown, a highly calcified structure while cementum covers the root. ⦿ The second layer is the dentin and the pulp forming the core respectively. Structure of the Teeth ⦿ Basically the tooth consists of Four Type of Tissues; 1. Enamel 2. Dentin 3. Pulp 4. Cementum Four Type of Tissues; 1. Enamel ⦿ It is the hardest tissue in the human body, covering the crown of the tooth. ⦿ It is highly mineralized tissue as 96% of it’s content is mineral organic content and water comprising the rest. Four Type of Tissues; 2. Dentin ⦿ A hard yellow substance, dentin makes up most of the tooth/main bulk. Coronal Dentin - crown portion Radicular Dentin - root area Dentino-Enamel Junction / DEJ - Junction between the enamel and dentin Four Type of Tissues; 2. Dentin ⦿ It is the dentin that gives the tooth its slightly yellowish tint. ⦿ Any insult/injury to the dentin is sure to cause you pain. Four Type of Tissues; 3. Cementum ⦿ covers the root and holds the tooth in place within the jawbone ⦿ is as hard as bone but not as hard as enamel, which enables the tooth to; 1. withstand the pressure of chewing 2. protects it from harmful bacteria 3. changes in temperature from hot and cold foods Four Type of Tissues; 3. Cementum ⦿ Attached to the alveolar bone by the fibers of the Periodontal Ligament and to the soft tissue of the gingiva by the gingival fibers Four Type of Tissues; 4. Pulp ⦿ is the innermost portion of the tooth. ⦿ Unlike the other parts of the tooth, the pulp is soft. ⦿ It is made of; 1. connective tissue 2. nerves 3. blood vessels which nourish the tooth. Four Type of Tissues; 4. Pulp ⦿ Two Parts: 1. Pulp Chamber - at the crown portion - Contains the coronal Pulp 2. Pulp Canal - at the root area - Contains the Radicular Pulp ⦿ Collectively known as PULP CAVITY Four Type of Tissues; 4. Pulp ⦿ Blood Vessels and Nerves enter the root through a small hole at the very bottom of the tooth called the Apical Foramen. Apical Foramen ⦿ Opening at the apex of a root through which the nerve and blood vessels of the pulp enters and exits. Apex ๏ Dentino-Cemental Junction ๏ Terminal end of a root by which the pulp tissue enters and exits Alveolar Process ๏ Bony process of the jaw which houses the tooth in place in the dental arch Structures of the Periodontium Periodontal Ligament Membrane Dense connective tissue organized into fiber groups that connects the cementum covering of the root of the tooth with the alveolar bone of the socket wall Periodontal Ligament Membrane 9 Principal Periodontal Ligaments / Fibers Alveolar Bone Proper / Alveolus The part of the alveolar process that lines the bony sockets into which the roots of the teeth are embedded  Supporting Alveolar Bone Part of the bone which surrounds the Alveolar Bone Proper and gives support to the sockets  Gingiva Part of the oral mucosa that covers the alveolar processes of the jaws and surrounds the cervical areas of the teeth. Parts: 1. Free / Marginal / Unattached Gingiva 2. Attached Gingiva 3. Gingival Sulcus Free Gingiva / Marginal Gingiva part of the gingiva that surrounds the tooth in a collar like fashion and is not directly attached to the tooth surface. 1.5 - 2 mm wide Free Gingiva / Marginal Gingiva Free Gingival Margin - Terminal edge of the free gingiva Free Gingival Groove - Separates the Free Gingiva from the Attached Gingiva  Gingival Sulcus V - shaped shallow crevice 1.8 mm Bounded by the free gingiva and a tooth surface Presence of curricular fluid  Attached Gingiva the portion of the gingiva extending from the gingival margin to the alveolar mucosa  Interdental Papilla / Gingiva Occupies the gingival embrasure Anterior Region Pyramidal form & flattened over molar region Scalloped form Presence of interdental col Interdental Gingiva  Alveolar Mucosa Lines the alveolar bone of the oral cavity Muco-Gingival Junction Surfaces and Ridges of the Teeth Five Surfaces of the Teeth 1. Labial / Buccal Surface 2. Lingual Surface 2. Mesial Surface 3. Distal Surface 5. Incisal / Occlusal Surface Tooth Surfaces Incisors and Canine - 4 surfaces and 1 ridge Premolars and Molars - 5 surfaces Five Surfaces of the Teeth Labial Surface The surface of the tooth facing towards the lips Anterior Teeth ( Incisors and Canines ) Five Surfaces of the Teeth Buccal Surface Surface facing towards the cheek area / buccal mucosa Posterior Teeth ( Premolars to Molars ) Five Surfaces of the Teeth Labial and Buccal surfaces are collectively called, FACIAL SURFACES Five Surfaces of the Teeth Lingual Surfaces All surfaces facing towards the tongue area Five Surfaces of the Teeth Occlusal Surfaces Surface of the premolars and molars which comes in contact with those in the opposite jaw during the act of closure (occlusion) Five Surfaces of the Teeth Incisal Surfaces Incisors and Canines Surfaces that comes in contact with the opposite teeth during occlusion Five Surfaces of the Teeth PROXIMAL SURFACES Surfaces of the teeth facing towards the adjoining teeth in the same dental arch Either MESIAL or DISTAL in reference to the position of the surface relative to the median line of the face Five Surfaces of the Teeth PROXIMAL SURFACES Midline - median line of the face Vertical line drawn through the center of the face passing between the central incisors at their point of contact with each other in both the maxilla and the mandible. Five Surfaces of the Teeth PROXIMAL SURFACES 1. Mesial Surface - proximal surfaces facing towards the median line 2. Distal Surface - surfaces most distant or away from the midline Contact Area The area of the medial and distal surface of a tooth which touches its neighboring tooth in the same arch. Other Landmarks Cusp, Tubercle, Cingulum, Ridge, Marginal Ridge Triangular Ridge, Transverse Ridge, Oblique Ridge Fossa, Sulcus Developmental Groove, Supplemental Groove Pit, Lobe Cusp An elevation or mound on the crown portion of a tooth making up a division part of the occlusal surface Tubercle A small elevation on some portion of the crown produced by an extra formation of enamel Deviations from the typical form Cingulum Latin word for “girdle” Is the lingual lobe of an anterior tooth Makes up the bulk of the cervical third of the lingual surface Ridge Any linear elevation on the surface of a tooth and is named according to location Ex. Buccal Ridge, Lingual Ridge, Marginal Ridge Marginal Ridge Rounded borders of the enamel that forms the mesial and distal margins of the occlusal surfaces of the premolars and molars The mesial and distal margins of the lingual surfaces of the incisors and canines. Triangular Ridge Descends from the tips of the cusps of molars and premolars towards the central part of the occlusal surfaces Are named according to the cusp that they belong Triangular Ridge of the buccal cusp of the Maxillary First Premolar Transverse Ridge Union of two triangular ridge ( ex. buccal and lingual ) crossing transversely the surface of a posterior tooth. Oblique Ridge A ridge crossing obliquely the occlusal surface of maxillary molars Formed by the union of the triangular ridge of the distobuccal cusp and the distal ridge of the mesiolingual cusp Fossa An irregular depression or concavity Lingual Fossae - lingual surfaces of incisors Central Fossae - occlusal surfaces of molars Formed where there is a junction of grooves Triangular Fossae Found on molars and premolars on the occlusal surfaces medial or distal to marginal ridges Sometimes found on the lingual surfaces of maxillary incisors at the edge of the lingual fosse where the marginal ridges and the cingulum meet. Sulcus A long depression or valley in the surface of a tooth between ridges and cusps , the inclines of which meet at an angle Has a Developmental Grove at the junction of its inclines. Developmental Groove Is a shallow groove or line between the primary parts of the crown or root. Supplemental Groove Less distinct Also a shallow linear depression on the surface of a tooth, but is supplemental to a developmental groove and does not mark the junction of primary parts. Pits Are small pinpoint depressions located at the junction of developmental grooves or at terminals of those grooves. Central Pit - a term used to describe a landmark in the central fossa of molars where developmental grooves join. Lobe Is one of the primary sections of formation in the development of the crown. Cusps and crowns are representatives of lobes Mamelons any of the three rounded protuberances found on the incised surfaces of newly erupted incisor teeth. Roots 1. Mono-Rooted - 1 Root (Max. and Mand. Anterior Teeth) 2. Bi-Rooted - 2 Roots (Max. Pre Molars and Mand. Molars) 3. Multi-Rooted - 3 or more Roots (Max. Molars) Divisions into Thirds, Line Angles and Point Angles The use of Line Angles and Point Angles are for descriptive terms to indicate a location of a tooth surface. Division of Thirds : ROOT Root : 1. Cervical Third 2. Middle Third 3. Apical Third Division of Thirds : CROWN Cervico Incisal/Occlusal : Incisal / Occlusal Thirds, Middle Third and Cervical Third. Division of Thirds : CROWN Mesiodistally : Mesial Third, Middle Third and Distal Third Division of Thirds : CROWN Labio/Buccolingually : Labial / Buccal Third, Middle and Lingual Thirds Line Angle Formed by the junction of two surfaces and derives its name from the combination of 2 surfaces that join. Line Angle Point Angle Formed by the Formed by the junction of two junction of 3 surfaces. surfaces and derives Derives its name its name from the from the combination combination of 2 surfaces that join. of the names of the surfaces forming it. Line Angles of Anterior Teeth Line Angles of Posterior Teeth Point Angles of Anterior Tooth Point Angles of Posterior Teeth Line Angles Anterior Tooth Posterior Tooth 1. Mesiolabial 1. Mesiobuccal 2. Mesiolingual 2. Mesiolingual 3. Distolabial 3. Distobuccal 4. Distolingual 4. Distolingual 5. Labioincisal 5. Bucco occlusal 6. Linguoincisal 6. Linguo occlusal 7. Mesioincisal 7. Disto occlusal 8. Distoincisal 8. Mesio occlusal Point Angles Anterior Tooth Posterior Tooth 1. Mesiolabioincisal 1. Mesiobucco-occlusal 2. Mesiolinguoincisal 2. Mesiolinguo-occlusal 3. Distolabioincisal 3. Distobucco-occlusal 4. Distolinguoincisal 4. Distolinguo-occlusal Summary : Terminology is an essential basis for communication, and therefore the importance of learning the nomenclature for dental anatomy cannot be minimized.  Dental Nomenclature  Nomenclature A rst step in understanding Oral Anatomy A System of Names used to describe or classify the material in a subject. fi Nomenclature Maxillary refers to the upper jaw or, the maxilla Mandibular refers to the lower jaw, or mandible  Nomenclature Primary / Deciduous Dentition “Primary “ - constituting, or belonging to the rst stage in any process. “Deciduous” - not permanent, transitory Permanent Dentition Succedaneous - successore dentition Non - Succedaneous fi Formulae for Mammalian Teeth uses denomination and numbers to differentiate the human dentition from other species. Denomination is represented by the initial letter in its name ( I - Incisor, C - Canine ) Each letter is followed by a horizontal line and the number of each type of tooth is placed above the line for maxilla, and below the line for mandible. Formulae for Mammalian Teeth Dental Formula for the Primary Dentition in humans Reading; Incisors (2 maxillary, 2 mandibular) Canines (1 maxillary, 1 mandibular) Molars (2 maxillary, 2 mandibular) Ten teeth all together on one side, right or left. Formulae for Mammalian Teeth Dental Formula for Permanent Human Dentition:  Tooth Numbering System Nomenclature: Order 1. Permanent or Deciduous? 2. Maxillary or Mandibular? 3. Right or Left? 4. Tooth Type (Incisor, Canine, Premolar or Molar)? Ex. Permanent Maxillary Right Lateral Incisor Tooth Numbering System “Short Hand“ system of tooth notation. Permanent Maxillary Right Lateral Incisor  Tooth Numbering System Symbolic System 1. Palmer Dental Notation Also known as Zsigmondy / Palmer Notation System Introduced by Adolph Zsigmondy of Vienna in 1861 Modi ed for the primary dentition in 1874 Recommended by the ADA in 1947 fi  Tooth Numbering System Symbolic System 1. Palmer Dental Notation Each Quadrant is represented by the following symbols Each Teeth is represented by: Letter - for Deciduous Teeth Number - for Permanent Teeth  Tooth Numbering System Symbolic System 1. Palmer Dental Notation The arches are divided into 4 quadrants with the entire dentition been noted as follows: Primary Dentition Permanent Dentition  Tooth Numbering System Symbolic System 1. Palmer Dental Notation  Tooth Numbering System 2. Universal System of Notation Primary Dentition - uses upper case letters for each of the primary teeth - beginning with the Maxillary Right 2nd Molar with Letter A. - end in Mandibular Right 2nd Molar  Tooth Numbering System 2. Universal System of Notation Permanent Dentition - uses numbers 1- 32, - beginning with the Maxillary Right 3rd Molar - end in Mandibular Right 3rd Molar  Tooth Numbering System 3. FDI SYSTEM / TWO DIGIT SYSTEM Federation Dentaire Internationale Adopted by the WHO for both Primary and Permanent Dentition  Tooth Numbering System 3. FDI SYSTEM / TWO DIGIT SYSTEM First Digit - represents the quadrant to which the teeth is located Second Digit - represents the type of tooth 1 2 5 6 87654321 12345678 54321 12345 87654321 12345678 54321 12345 4 3 8 7 Ex. 11 - Permanent Maxillary Right Central Incisor 65 - Primary Maxillary Left Second Molar  Tooth Numbering System 3. FDI SYSTEM / TWO DIGIT SYSTEM  Tooth Numbering System 3. FDI SYSTEM / TWO DIGIT SYSTEM EXAMPLES FDI SYSTEM TOOTH 11 PERMANENT MAXILLARY RIGHT CENTRAL INCISOR EXAMPLES FDI SYSTEM TOOTH 85 PRIMARY MANDIBULAR RIGHT SECOND MOLAR EXAMPLES UNIVERSAL SYSTEM TOOTH 11 PERMANENT MAXILLARY LEFT CANINE EXAMPLES UNIVERSAL SYSTEM TOOTH E PRIMARY MAXILLARY RIGHT CENTRAL INCISOR EXAMPLES C PRIMARY MANDIBULAR RIGHT CANINE EXAMPLES 5 PERMANENT MAXILLARY LEFT SECOND PREMOLAR  One Way Traffic 1. URPQ 2 2. UA 3 1 3. ULPQ 4. LLPQ 5. LA 6 4 6. LRPQ 5  IDENTIFYING THE TOOTH 1. Side - Right or Left Side 2. Arch - Upper or Lower / Maxillary or Mandibular 3. Set - Primary or Permanent Tooth 4. Tooth - Incisors, Canine, Premolars or Molars