Oral Anatomy & Histology (Review: Outcome 1) Flashcards
Anatomy
The study of the human body’s shape and structure
Nomenclature
System of name in science
Anatomical position
- Standing erect (upright)
- Toes pointed forward & feet flat on the floor
- Eyes directed to the horizon facing observer
- Arms by the sides with palms facing forward
Superior
ABOVE another part or closer to the head
- Ex. Nose is superior to the mouth
Inferior
BELOW another part, or closer to feet
- Ex. Heart is inferior to neck
Anterior
Toward the FRONT
- Ex. Heart is anterior to spine
Posterior
Toward the BACK
- Ex. Ear is posterior to nose
Medial
Toward the midline of the body
- Ex. Nose is medial to ears
Lateral
Away from midline of the body structure
- Ex. Ears are lateral to eyes
Proximal
CLOSE to a point of attachment or closer to trunk of body
- Ex. Elbow is proximal to wrist (close to should attachment)
Distal
FURTHER from a point of attachment or further from trunk of body
- Ex. Fingers are distal to wrist
Dorsal
On the back
- Ex. Spine is on dorsal side of body
Vertral
On the front
- Ex. Face is on ventral side of body
Planes (of the body)
Imaginary lines used to divide the body into sections
Midsagittal plane
VERTICAL plane that divides body into equal right and left halves
Parasagittal plane
ANY VERTICAL plane that does not pass through the midline of body & divides body into unequal right & left
Frontal/Coronal plane
Divides body into ANTERIOR & POSTERIOR portions
Horizontal/Transverse plane
Divides body into SUPERIOR & INFERIOR portions
Parts of Anterior Teeth
Central incisors, Lateral incisors, Canines (Cuspids)
Parts of Posterior Teeth
Premolars (Bicuspids), Molars
Make up of Permanent Dentition
Each arch has:
a. 4 permanent incisors (2 Central, 2 Lateral)
b. 2 permanent canines (cuspids)
c. 4 permanent premolars (bicuspids)
d. 6 permanent molars
How many permanent teeth in total?
32 teeth in a mouth
How many in permanent Maxillary and Mandibular arches?
Each have 16 teeth
How many permanent teeth in each quadrant?
8 teeth in each quadrant
a. 3 molars
b. 2 premolars (Bicuspids)
c. 1 canine (Cuspid)
d. 2 incisors (Central and Lateral)
How many primary teeth in each quadrant?
5 teeth in each quadrant
a. 2 molars
b. 1 canine (Cuspid)
c. 2 incisors (Central and Lateral)
How many primary teeth in total?
20 teeth in total
(10 in each arch)
Dental Sextants
Dentition is divided into 6 segments
- Each arch is divided into 3:
- 5 teeth in each posterior sextants (3 molars, 2 premolars) - right and left side
- 6 teeth in each anterior sextant (2 canines, 4 incisors - Central & Lateral)
Anatomical crown
The part covered by enamel (whole crown of the tooth, whether it has erupted or not)
Always remains the same
Clinical crown
The part of the tooth that can be seen in the mouth (this may include all or only part of the anatomical crown & may even include part of root)
Bifurcation
Division of the root trunk into 2
- found on lower molars
Trifurcation
Division of the root trunk into 3
- provides tooth with maximum anchorage against biting force
- found on upper molars where anchorage is essential
Composition of the tooth structure (Tooth tissues)
- Enamel
- Dentin
- Cementum
- Pulp
Enamel
A hard protective tissue that covers the crown of the tooth
- hardest tooth structure
- smooth (self-cleansing)
- thickest at the tip of the crown, thinner at cervical portion
Dentin
Makes up the main bulk of the tooth
- Found in both the crown and root of the tooth
- softer than enamel, harder than cementum or bone
- can continue to form throughout lifespan of a tooth
Cementum
Covers the root of the tooth
- attaches the tooth to the bone
- softer than enamel or dentin (least calcified tooth)
- light yellow in colour
Pulp
Soft connective tissue containing nerves & blood vessels in the center of tooth (non-mineralized)
- surrounded by dentin
- nourishing and sensory (pain) function
- composed of blood vessels, lymph vessels, connective tissues, nerve tissues and odontoblasts (special dentin formation cells)
Parts of pulp cavity
- Pulp chamber
- Pulp canal
*Pulp horn = extension of the chamber
Common structures of the tooth
- Crown
- CEJ (Cemento-enamel junction) also called Cervical line or cervix
- Root
- Apex (terminal end of root –> Apical foramen = tiny opening in the apex for blood vessels and nerves to enter)
Periodontal Ligament
Suspends the tooth and provides it with nourishment
- located between bone of the alveolar process and cementum
Radicular
Have to do with the tooth root
- the radicular pulp is the pulp contained in the root
Incisors (Location, shape, function)
4 incisors in each arch (2 Central, 2 Lateral)
- Location: Central (side by side at midline); Lateral (on each side of the central incisors)
- Shape: Single rooted, crowns are arched and angle toward one sharp incisal edge
- Function: to cut or incise food with their thin edges
Tongue side is shovel shaped (helps move food to the posterior part of mouth)
Canines/Cuspids (Location, shape, function)
2 cuspids in each arch
- Location: Next to lateral incisors, establishes the corner of the arches
- Shape: Anchored with the longest root, one pointed cusp
- Function: Used for holding, grasping, and tearing food
Referred to as the CORNERSTONE of the mouth
Premolars/Bicuspids (Location, shape, function)
4 premolars in each arch (2 first premolars, 2 second premolars)
- Location: First premolars are next to canines, followed by second premolars
- Shape: Maxillary first premolars have bifurcated roots, all others have 1 root, 1 prominent cusp with 1 or 2 lesser lingual cusps
- Function: Hold food, like canines because they have cusps; also to grind food
Molars (Location, shape, function)
6 molars in each arch (3 in each quadrant)
1st, 2nd, 3rd molars (Wisdom tooth)
- Location: First molars are next to second premolars, second molars next to the first molars and third molars next to second molars (the furthest in the mouth)
- Shape: Bifurcated or trifurcated roots, broad chewing surfaces with 4 to 5 cusps
- Function: Grinding or chewing food
What are the tooth surfaces?
a. Occlusal surfaces (posterior teeth)
b. Incisal surfaces (anterior teeth)
c. Lingual surfaces (palatal maxillary teeth) - tongue side
d. Facial surfaces (Buccal, Labial)
e. Proximal surfaces (Mesial, Distal)
f. Interproximal area (space between the teeth)
Line Angles
Separate two surface of a tooth by forming a junction of the two surfaces
Point Angles
The point in which 3 surfaces will meet (only the corners)
Rules of determining line and point angles
Line Angles:
1. Sides = Mesial or Distal (M/D)
2. Front/back = Facial or Lingual (F/L)
Point Angles:
1. Sides
2. Front/back
3. Biting surfaces = incisal or occlusal
Anterior Teeth - Line Angles
- Distolabial
- Mesiolabial
- Distolingual
- Mesiolingual
- Linguoincisal
- Labioincisal
Posterior Teeth - Line Angles
- Distobuccal
- Mesiobuccal
- Distolingual
- Mesiolingual
- Disto-occlusal
- Mesio-occlusal
- Bucco-occlusal
- Linguo-occlusal
Anterior Teeth - Point Angles
- Mesiolabioincisal
- Distolabioincisal
- Mesiolinguoincisal
- Distolinguoincisal
Posterior Teeth - Point Angles
- Mesiobucco-occlusal
- Distobucco-occlusal
- Mesiolinguo-occlusal
- Distolinguo-occlusal
What are the 3 anatomic features of teeth?
- Contours
- Contacts
- Embrasures
*Anatomic features of the teeth help maintain their positions in the arch and protect the tissues during mastication
Contours of teeth
All teeth have a curved surface except when tooth is fractured or worn
- Some surfaces are convex, some are concave
- General principle: crown of tooth narrows toward the cervical line
- Facial & Lingual contours (provides gingiva with adequate stimulation for health, while protecting it from damage from food)
- Mesial & Distal contours (provide normal contact and embrasure form)
Height of contour
The “bulge” or widest point on a specific surface of the crown
- Contact areas on mesial and distal surfaces are usually considered the height of contour on proximal surfaces
Contact (Anatomic Feature of teeth)
The area where the crowns of adjacent teeth in the same arch physically touch on each proximal surface
Proper contact serves the following purposes:
- Prevents food from being trapped between the teeth
- Stabilizes the dental arches by holding the teeth in either arch in positive contact with each other
- Protects the interproximal gingival tissue from trauma during mastication
Embrasures (Anatomic Feature of teeth)
A triangular space in a gingival direction between the proximal surfaces of 2 adjoining teeth in contact
- They are continuous with the interproximal spaces between the teeth
What are the clinical considerations for tooth surfaces?
- The tooth’s angles, height of contour, and spaces define the front or face of a tooth when the design of a patient’s smile is considered, because these features are noted first when contemplating someone’s smile
- Altering placement and shape of these features changes the face of a tooth and its perceived size and appearance of smile
- Note: Mesial part of the face and silhouette of a tooth is more angled vertically than distal part
Developmental Depressions
Outline the separations among the labial developmental lobes
Cingulum
A raised, rounded area on the cervical third of the lingual surface
- All anteriors on the lingual surfaces have a cingulum
Mamelons
Rounded enamel extension on the incisal ridges of incisors (wears off)
Developmental Groove
A sharp, deep, V-shaped linear depression that marks the junction among the developmental lobes
- Anteriors may have on their lingual surface
- Posterior: located in the same place and mark the junction among the developmental lobes
- 3 different developmental grooves:
i. Supplemental groove
ii. Marginal groove (cross the marginal ridges)
iii. Triangular groove (separate marginal ridge from triangular ridge of a cusp)
Fossa/Fossae
A shallow, wide depression
- On Anteriors: located on lingual
- On Posteriors: Triangular fossa
Developmental Pits
Located in the deepest part of each fossa
Occlusal Pits
A sharp pinpoint depression where 2 or more grooves meet
Marginal Ridge (Anterior)
Present on lingual surface
- A rounded, raised border on the mesial and distal sides
Marginal Ridge (Posterior)
Raised border on the occlusal surface
- Located on distal and mesial surfaces
Triangular Ridges
Cusp ridges that descend from the cusps tips toward the central part of the occlusal table
Transverse Ridge
Joining of 2 triangular ridges crossing the occlusal table transversely, or from the labial to lingual
Incisal Ridge
The incisal surface of the long crown of an anterior tooth
Ala-Tragus Line
Used to landmark for x-rays
Ala of nose = wing
Tragus of ear = projection anterior to the external opening of ear
Vestibule
The space between the teeth and the inner mucosal lining of the lips and cheeks
Oral Cavity Proper
The space on the tongue side within the upper and lower dental arches
Parts of the Vestibule
- Vestibular (Mucolabial fold)
- Labial frenulum
- Labial mucosa
- Alveolar mucosa
- Labial Maxillary gingiva
- Labial Mandibular gingiva
Linea Alba (Buccal Mucosa)
White ridge of raised tissue extends horizontally at the level where the maxillary and mandibular teeth come together
- caused by friction with the teeth
Fordyce Spots (Buccal Mucosa)
Normal, small, yellowish elevations that may appear on the buccal mucosa
Mucogingival Junction
A distinct line of colour change where the alveolar mucosa meets with attached gingivae
Attached gingiva
A lighter colour gingiva
- extends from the base of the sulcus to the mucogingival junction
- stippled, dense tissue that is self-protecting, firmly bound and resilient
Alveolar Mucosa
Covers the alveolar bone
- Loosely attached to bone
- Redder in colour than labial or buccal mucosa
Frenum (Frenulum)
A narrow fold of mucous membrane passing from fixed tissue to more movable tissue
- Found at the inner midline of both upper and lower lips and by the cuspid or bicuspid areas
- The Frena/Frenula attach the lips to the alveolar mucosa and the tongue to the floor of the mouth
Gingiva
Surrounds the tooth like a collar
- Self-cleansing
- Firm and resistant
- Can be tightly adapted to tooth and bone
- Stippled and resemble the rind of an orange
Bony Eminence (Attached gingiva)
Raised contour of bone that follows the roots of the teeth
- Canine Eminence
Maxillary Tuberosity (Attached Gingiva)
Small extension of bone posterior to last maxillary tooth
Retromolar area
Bone posterior to last mandibular tooth
Exostoses
Localized growth of bone
Functions of Hard Palate
- Crush food
- Assist in swallowing
- Prevent injury to the oral structures by determining texture and temperature of food
Characteristics and Functions of Soft Palate
Posterior third of palate
- Composed of: muscular fibers covered with mucosa
- Most posterior portion is the uvula
- Function: Assists by closing off the nasal cavity during swallowing or speaking - specifically the uvula
Parts of the Tongue
- Dorsum: upper surface
- Ventral: under surface
- Median sulcus: the depression down the midline
Circumvallate/Vallate Papillae
A V-shaped row of circular, raised papillae about 2/3 of the way back
- Involved in gag reflex
- Contain taste buds
Filiform Papillae
Threadlike projections of epithelial tissue
- Cover the anterior 2/3 of the tongue
- Provide tactile sense
Fungiform Papillae
Reddish, small, mushroom-shaped dots
- Dorsal surface
- Anterior, 2/3 of the tongue
- Contain taste buds
Foliate Papillae
On lateral surface, back in the region of the circumvallate papillae
- Some taste buds
Lingual Tonsils
- Near the midline on the dorsum of the tongue
- Directly behind the circumvallate papilla
- Similar to the tissue of palatine tonsils
- Works as a defense mechanism in that area
Characteristics of Ventral surface of Tongue
- Underside of tongue
- Large visible blood vessels and deep lingual veins
- Plica fimbriate/e
- Sublingual caruncle
Types of Mucous Membranes
- Masticatory Mucosa
- Specialized Mucosa
- Lining Mucosa
Masticatory Mucosa
Oral mucosa that covers the hard palate, dorsum of the tongue, and gingiva
Specialized Mucosa
Mucous membrane on the tongue in the form of lingual papillae (structures associated with sensations of taste)
Lining Mucosa
Mucous membrane that covers the inside of the cheeks, vestibule, lips, soft palate, and underside of the tongue
- Acts as a cushion for underlying structures
Universal Numbering System
Most widely used system in U.S. for the designation of both dentitions because it is adaptable to electronic data
Universal Numbering System for Primary Dentition
Consecutive arrangement by using capital letters
A through T - starting with maxillary right second molar, moving clockwise, and ending with mandibular right second molar
e.g.
- H = left maxillary canine
- Q = right mandibular lateral incisors
Universal Numbering System for Permanent Dentition
Consecutive arrangement using digits 1 through 32
- Starting with maxillary right third molar, moving clockwise, and ending with the mandibular right third molar
e.g.
- 13 = maxillary left second premolar
- 27 = mandibular right canine
Federation Dentaire Internationale (FDI)
System used internationally (International Numbering System - INS)
- Uses a two-digit code
- First digit = quadrant
- Second digit = tooth’s position in this quadrant
FDI for Primary Dentition
Digits: 5 to 8
- Clockwise, starting on upper right
E.g.
6.4 = Maxillary left first molar (Quad #6, tooth #4)
FDI for Permanent Dentition
Digits: 1 to 4
- Clockwise, starting on upper right
E.g.
3.2 = Mandibular left lateral incisors (Quad #3, tooth #2)
Palmer Method
A right-angle symbol indicating quadrants and arch, with tooth number placed inside
