Presentation is loading. Please wait.

Presentation is loading. Please wait.

Human Dentition.

Similar presentations


Presentation on theme: "Human Dentition."— Presentation transcript:

1 Human Dentition

2 Dental Anatomy Nomenclature
The Jaws

3 Dental Arches

4 A. The maxilla B. The mandible is two bones forming the upper jaw;
they are rigidly attached to the skull. B. The mandible is a horse-shoe shaped bone which articulates with the skull by way of the temporo-mandibular joint the TMJ.

5 Quadrants: right & left quadrants
Maxillary right and left. Mandibular right and left. 4 Quadrants

6 Functions of Teeth *Efficient mastication of food.
*Maintenance of a normal facial appearance. *Formulation of clear speech. Incisor Canine Premolar Molar

7 1- Mastication: At least two projections (cusps). Tearing and grinding
Wedge like Cutting and tearing Multiple projections (cusps) Grinding Chisel like Cutting or incising Incisors Canine Premolar Molar

8 2- Appearance: 3- Speech: 4- Growth of jaws:
- Well arranged clean teeth with proper alignment give nice appearance to the face. – Teeth give support to the facial expressions. 3- Speech: for clear pronunciation and production of sound. 4- Growth of jaws: The teeth play a role in the growth of the jaws in some periods of life.

9 Types of Teeth

10 Anterior Teeth for cutting & tearing food Posterior Teeth

11 Incisors function as cutting or shearing instruments for food.
Canines possess the longest roots of all teeth and are located at the corners of the dental arch. Premolars act like the canines in the tearing of food and are similar to molars in the grinding of food. Molars are located nearest the temporomandibular joint (TMJ), which serves as the fulcrum during function. Incisors (central and lateral) The incisors are located near the entrance of the oral cavity and function as cutting or shearing instruments for food. From a proximal view, the crowns of these teeth have a triangular shape with a narrow incisal surface, including the incisal edge, and a broad cervical base. The incisors contribute significantly in cutting actions and other functions; esthetics; and phonetics. Canines The canines possess the longest roots of all teeth and are located at the corners of the dental arch. They function in the seizing, piercing, and tearing of food, as well as in cutting. From a proximal view the crown also has a triangular shape with a thick incisal ridge. The stocky anatomic form of the crown and length of the root are reasons why these teeth are strong, stable abutment teeth for a fixed or removable prosthesis. The canines serve as imortant guides in occlusion because of their anchorage and position in the dental arches. Premolars The premolars serve a dual role in function: they act like the canines in the tearing of food and are similar to molars in the grinding of food. Whereas the first premolars are angular, with their facial cusps resembling the canines, the lingual cusps of the maxillary premolars and molars have a more rounded anatomic form. The occlusal surfaces present in a series of curves in the form of concavities and convexities that should be maintained throughout life for correct occlusal contacts and function. Molars The molars are large, multicusped, strongly anchored teeth located nearest the temporomandibular joint (TMJ), which serves as the fulcrum during function. These teeth have a major role in the crushing, grinding, and chewing of food to the smallest dimensions suitable for deglutition. The occlusal surfaces of both premolars and molars act as a myriad of shears that function in the final mastication of food. The premolars and molars are also important in maintaining the vertical dimension of the face. All definitions from: Sturdevant JR, Lundeen TF, Sluder TB Jr. Clinical significance of dental anatomy, histology, physiology, and occlusion. In: Roberson TM, Heymann HO, Swift EJ Jr, eds. Sturdevant's Art and Science of Operative Dentistry. 4th ed. St. Louis, MO: Mosby; 2002:15-16.

12 Anterior Teeth- Upper Anterior Teeth- Lower Canine Central Incisors
lateral Canine Central Incisors Canine lateral Anterior Teeth- Lower

13 Premolars: (in permanent only)

14 First premolar & Second premolar
Upper First premolar & Second premolar Lower

15 Upper First second Molars Wisdom tooth =Third permanent molar Lower

16 Single-rooted Multi-rooted

17 Types of Dentitions: Primary & Permanent Dentition

18 Types& forms: Deciuous Set of Teeth.: Permanent Set of Teeth.:
2 incisors, 1 canine, 2 molars in each quadrant Permanent Set of Teeth.: 2 premolars, 3 molars

19 Types of Dentitions: I-Primary Dentition

20 Deciduous ,baby, milk teeth:
a. Twenty ( 20) primary teeth. b. 10 in each arch c in each quadrant In function: 2 years  12 years 6 years  years Eruption of first permanent molar Shedding of last primary molar

21 ERUPTION  pure permanent dentition From 6 months to 2 years:
 pure deciduous dentition * At three years all roots are complete From 6y to 12 y:  mixed dentition From 12 y onwards:  pure permanent dentition

22 Mixed Dentition Period

23 6 years  eruption of first permanent molar

24 In function: 12 years through out life

25 Teeth: Identification Tooth Surfaces
Each tooth has Five surfaces: Labial Apical Lingual Distal Apical Mesial Apical Labial Lingual Distal Mesial Incisal Tooth surfaces include: Apical: Pertaining to the apex or root of the tooth Labial: Pertaining to the lip; describes the front surface of anterior teeth Lingual: Pertaining to the tongue; describes the back (interior) surface of all teeth Distal: The surface of the tooth that is away from the median line Mesial: The surface of the tooth that is towards the median line Incisal Incisal Surfaces of teeth are identified by the relationship to surrounding orofacial structures

26 palatal Apical: Pertaining to the apex or root of the tooth Labial: Pertaining to the lip; describes the front surface of anterior teeth Lingual: Pertaining to the tongue; describes the back (interior) surface of all teeth Distal: The surface of the tooth that is away from the median line Mesial: The surface of the tooth that is toward the median line

27 Functioning Surfaces:
chewing/biting surfaces of teeth : OCCLUSAL: chewing surfaces of posterior teeth INCISAL: the anteriors’ biting surface

28 Oral Anatomy and Physiology
The Dental Tissues: Enamel Dentin Pulp Chamber Odontoblast Layer Periodontal Ligament Gingiva Alveolar Bone Cementum Pulp Canals Apical Foramen Enamel Dentin Odontoblast Layer Gingiva Pulp Chamber Periodontal Ligament Cementum The anatomic tooth crown is the portion of the tooth covered by enamel. The anatomic root is the lower two thirds of a tooth. The roots are normally subgingival, buried in bone, and serve to anchor the tooth in position. The pulp cavity houses the dental pulp, an organ of myelinated and unmyelinated nerves, arteries, veins, lymph channels, connective tissue cells, and various other cells involved in formative or developmental, nutritive, sensory, protective, and defensive or reparative processes. Alveolar Bone Pulp Canals Apical Foramen

29 Oral Anatomy and Physiology
The 3 parts of a tooth: Anatomic Crown Anatomic Crown Anatomic Root Pulp Chamber Pulp Chamber The anatomic tooth crown is the portion of the tooth covered by enamel. The anatomic root is the lower two thirds of a tooth. The roots are normally subgingival, buried in bone, and serve to anchor the tooth in position. The pulp cavity houses the dental pulp, an organ of myelinated and unmyelinated nerves, arteries, veins, lymph channels, connective tissue cells, and various other cells involved in formative or developmental, nutritive, sensory, protective, and defensive or reparative processes. Anatomic Root

30 Oral Anatomy and Physiology
The anatomic crown is the portion of the tooth covered by enamel. The anatomic root is the lower two thirds of a tooth. The pulp chamber houses the dental pulp, an organ of myelinated and unmyelinated nerves, arteries, veins, lymph channels, connective tissue cells, and various other cells. Anatomic Crown Pulp Chamber The anatomic tooth crown is the portion of the tooth covered by enamel. The anatomic root is the lower two thirds of a tooth. The roots are normally subgingival, buried in bone, and serve to anchor the tooth in position. The pulp cavity houses the dental pulp, an organ of myelinated and unmyelinated nerves, arteries, veins, lymph channels, connective tissue cells, and various other cells involved in formative or developmental, nutritive, sensory, protective, and defensive or reparative processes. Anatomic Root

31 Oral Anatomy and Physiology
Enamel The 4 main dental tissues: Dental Pulp Dentin Enamel Dentin Cementum Dental Pulp The 4 main dental tissues are: Enamel Dentin Cementum Dental pulp Cementum

32 Dental Tissues—Enamel2
Structure Highly calcified and hardest tissue in the body Crystalline in nature Enamel rods Insensitive—no nerves Acid-soluble—will demineralize at a pH of 5.5 and lower Cannot be renewed Darkens with age as enamel is lost Fluoride and saliva can help with remineralization Enamel can be lost by:3,4 Physical mechanism Abrasion (mechanical wear) Attrition (tooth-to-tooth contact) Abfraction (lesions) Chemical dissolution Erosion by extrinsic acids (from diet) Erosion by intrinsic acids (from the oral cavity/digestive tract) Multifactorial etiology Combination of physical and chemical factors Structure Highly calcified and hardest tissue in the body Crystalline in nature Enamel rods Insensitive—no nerves Acid-soluble—will demineralize at a pH of 5.5 and lower Cannot be renewed Darkens with age as enamel is lost Fluoride and saliva can help with remineralization

33 Dental Tissues—Dentin2
Softer than enamel Susceptible to tooth wear (physical or chemical) Does not have a nerve supply but can be sensitive Is produced throughout life Will demineralize at a pH of 6.5 and lower Three classifications Primary Secondary Tertiary Softer than enamel Susceptible to tooth wear (physical or chemical) Does not have a nerve supply but can be sensitive Is produced throughout life Three classifications Primary Secondary Tertiary Will demineralize at a pH of 6.5 and lower Primary dentin forms the initial shape of the tooth. It is usually completed 3 years after tooth eruption (for permanent teeth). Secondary dentin is deposited after the formation of the primary dentin. Secondary dentin forms on all internal aspects of the pulp cavity, but in the pulp chamber of multirooted teeth it tends to be thicker on the roof and floor than on the side walls. Tertiary dentin, or “reparative dentin” is formed by replacement odontoblasts in response to moderate-level irritants such as attrition, abrasion, erosion, trauma, moderate-rate dental caries, and some operative procedures. It usually appears as a localized dentin deposit on the wall of the pulp cavity immediately subadjacent to the area of the tooth that has received the injury.

34 Dental Tissues—Dentin2
Three classifications: Primary dentin forms the initial shape of the tooth. Secondary dentin is deposited after the formation of the primary dentin on all internal aspects of the pulp cavity. Tertiary dentin, or “reparative dentin” is formed by replacement odontoblasts in response to moderate-level irritants such as attrition, abrasion, erosion, trauma, moderate-rate dental caries, and some operative procedures. Softer than enamel Susceptible to tooth wear (physical or chemical) Does not have a nerve supply but can be sensitive Is produced throughout life Three classifications Primary Secondary Tertiary Will demineralize at a pH of 6.5 and lower Primary dentin forms the initial shape of the tooth. It is usually completed 3 years after tooth eruption (for permanent teeth). Secondary dentin is deposited after the formation of the primary dentin. Secondary dentin forms on all internal aspects of the pulp cavity, but in the pulp chamber of multirooted teeth it tends to be thicker on the roof and floor than on the side walls. Tertiary dentin, or “reparative dentin” is formed by replacement odontoblasts in response to moderate-level irritants such as attrition, abrasion, erosion, trauma, moderate-rate dental caries, and some operative procedures. It usually appears as a localized dentin deposit on the wall of the pulp cavity immediately subadjacent to the area of the tooth that has received the injury.

35 Secondary physiologic irregular secondary dentin
Types of Dentin Dentin Primary physiologic dentin Secondary physiologic dentin Tertiary dentin or reparative dentin or reactionary dentin or irregular secondary dentin Mantle dentin Circumpulpal dentin Peritubular dentin Intertubular dentin

36 Dental Tissues—Dentin (Tubules)2
Dentinal tubules connect the dentin and the pulp (innermost part of the tooth, circumscribed by the dentin and lined with a layer of odontoblast cells) The tubules run parallel to each other in an S-shape course Tubules contain fluid and nerve fibers External stimuli cause movement of the dentinal fluid, a hydrodynamic movement, which can result in short, sharp pain episodes Dentin Pulp Tubule Odontoblast Cell Nerve Fibers The tubules run parallel to each other in an S-shape course. The tubules are filled with a fluid. External stimuli cause movement of the dentinal fluid, a hydrodynamic movement, which can result in short, sharp pain episodes. These details are important in understanding dentin hypersensitivity. Fluid

37 Presence of tubules renders dentin permeable to fluoride
Number of tubules per unit area varies depending on the location because of the decreasing area of the dentin surfaces in the pulpal direction The tubules run parallel to each other in an S-shape course. The tubules are filled with a fluid. External stimuli cause movement of the dentinal fluid, a hydrodynamic movement, which can result in short, sharp pain episodes. These details are important in understanding dentin hypersensitivity.

38 Association between erosion and dentin hypersensitivity3
Open/patent tubules – Greater in number – Larger in diameter Removal of smear layer Erosion/tooth wear Enamel Tubules Exposed Dentin Odontoblast Associations between erosion and hypersensitivity involve: Open/patent tubules Greater in number Larger in diameter Removal of smear layer Erosion/tooth wear Undercalcified Receding Gingiva

39 Oral Anatomy and Physiology
Dental Tissue—Cementum2 Thin layer of mineralized tissue covering the dentin Softer than enamel and dentin Anchors the tooth to the alveolar bone along with the periodontal ligament Not sensitive Cementum is: Thin layer of mineralized tissue covering the dentin Softer than enamel and dentin Anchors the tooth to the alveolar bone along with the periodontal ligament Not sensitive

40 Dental Tissue—Dental Pulp2
The Pulp is a soft mesenchymal connective tissue that occupies pulp cavity in the central part of the teeth. It is a special organ because of the unique environment

41 Morphlogy *The coronal pulp: it is present in the pulp chamber.
*The radicular pulp: it is that part of the pulp extending from the cervical region of the crown to the root apex. *Apical foramen: The pulp organs are continuous with the periapical tissue through the apical foramen.

42 Accessory canals: They are commonly seen to extend from the radicular pulp latrally through the root dentin to the periodontal ligament. They are numerous in the apical third of the root. Accessory canals

43 CORONAL PULP It is the pulp occupying the pulp chamber of the crown of the tooth In young teeth it resembles the shape of the outer dentin It has six surfaces : occlusal, mesial, distal, buccal, lingual and floor. Pulp horns are projections into the cusp This pulp constricts at the cervical region where it continues as the radicular pulp

44 RADICULAR PULP It is the pulp occupying the pulp canals of the root of the tooth In the anterior tooth it is single and in the posterior teeth it is multiple The radicular portions of the pulp is continuous with the periapical tissues through apical foramen As age advances the width of the radicular pulp is reduced, and so is the apical foramen.

45 APICAL FORAMEN Pulp cavity terminates at root apex as small opening called apical foramen Radicular pulp continuous with connective tissue of the periodontium through this foramen. Wide open during development of root Sometimes apical opening is found on the lateral side of the apex There may be 2-3 foramina split by cementum or dentin- APICAL DELTA

46 ACCESSORY CANAL Leading laterally from the radicular pulp into the periodontal tissue. Present in the apical third of the root sheath cells Formed due to premature loss of HERS or when developing root encounters a blood vessel. Overall occurrence is 33% May also be present at the furcation region

47 Functions of the Dental Pulp
Nutrition: blood supply for pulp and dentin. Sensory: changes in temp., vibration and chemical that affect the dentin and pulp. Formative: the pulp involve in the support, maintenance and continued formation of dentin. (dentinogenesis) Protective: Development and formation of secondary and tertiary dentin which increase the coverage of the pulp.

48 Defensive: triggering of inflammatory and immune response.
First line of defense to injuries and infection of dentine Tertiary dentine Immuno-competent Clearance of toxic substances

49 Dentin_pulp complex Dentin and pulp are embryologically, histologically, and functionally the same tissue and therefore are considered as a complex Both dentin and pulp have a common origin from the dental papilla.


Download ppt "Human Dentition."

Similar presentations


Ads by Google