Final Review Flashcards
How is melanin produced?
Produced by melanocytes
Passed through melanocytes to granular layer and absorbed into keratin
How much sun protection should you use?
SPF 30 and then reapply after 30 minutes + ever hour after that
How much does using tanning beds before age 30 increase the risk of melanoma?
75%- CT gets damaged
Which epithelial layer has the highest mitotic activity?
Stratum germinativum (basal layer)
Cell structures of skeletal muscle tissue
Myoblasts- muscles cells
Myofibrils- contractile elements (protein fibers- actin & myosin
Components of a muscle cell
Sarcoplasm- cytoplasm containing organelles
Sarcolemma- Cell membrane
Sarcoplasmic reticulum- System of tubes that communicates nerve impulses and enables contraction
Sarcomere- Contractile unit of myofibrils
What do mast cells produce?
AKA Leukocytes
Heparin- anticoagulant
Histamine- induces capillaries to release plasma
Where is the amniotic cavity located?
Forms from the amniotic sac above the epiblast and below the yolk sac
Cells of the developing embryo
Tropoblast
Epiblast
Hypoblast
When are tropoblasts formed and what do they give rise to?
Created during blastocyst formation as an outer layer of cells
Attaches blastocyst to the uterus during implantation
When are epiblasts formed and what do they give rise to?
Top layer of cells of the bilaminar germ disc
Gets renamed ectoderm–> becomes mesoderms–>endoderm
When are hypoblasts formed and what do they give rise to?
Bottom layer of cells in bilaminar germ disc
Hypoblast gets dumped into yolk sac (nourishment)
What is the primitive streak?
Elevation of epiblast on posterior border of primitive groove
Guides epiblast to form TGD
What is the primitive node?
Elevation of epiblast cells on the primitive pit
Guides proliferating epiblast to form future notochord
What does the prechordal plate form?
Oropharyngeal membrane
Separates future primitive mouth from primitive gut
Origin of the thyroid gland
Foramen cecum
Origin of the pituitary gland
Rathke’s Pouch forms the anterior pituitary gland
Associated structures of the frontonasal process
Lateral nasal process- alae of nose & nasolabial sulcus
Medial nasal processes- Columella & tip of nose, nasal septum, pre-maxilla
Intermaxillary segment- Philtrum, center of uppe rlip, premaxilla, alveolar ridge
Branchial grooves vs branchial pouches
Each have 4 pairs that correspond to the other
Grooves are external, pouches are internal
1st groove forms the external auditory canal. 1st pouch forms internal auditory canal
Remaining branchial grooves form the neck
2nd pouch forms tonsils
First branchial arch and associated structures
Posterior 2/3 upper lip, maxilla and hard palate
Cheeks and entire lower lip and mandibular arch
Anterior 2/3 of the tongue
How does linea alba form?
Fusion of the maxillary and mandibular processes
Associated structures of the 2nd branchial arch
Posterior 1/3 (root) of tongue
Reichert’s cartilage gives rise to: stapes, styloid process, lesser cornu of hyoid, superior aspect body of hyoid, perichondrium
Muscles of facial expression
7th facial nerve
How does a cleft lip form?
Partial or complete failure of the intermaxillary segment & maxillary process to fuse- failure of fusion btw the max process w/ the lateral borders of the center portion of the upper lip
Week 8
How do cleft palates form?
Premaxilla and/or secondary palate fail to fuse w/ nasal septum
And/or failure of premaxilla to fuse w/ secondary palate
Characteristics of inner enamel epithelium
Concave inner layer of the enamel organ
Single cell layer
When do stellate reticulum form?
Star shaped core cells form during the cap stage
Pushes apart OEE and IEE and helps form cap shape
Collapses during apposition
What is the function of stratum intermedium?
Transports nutrients to pre-ameloblasts during the apposition stage
Flat layer of cells between stellate reticulum and IEE
Bell stage
What does the cervical loop give rise to?
Gives rise to the cervix of the tooth–> future CEJ
Inferior circumference of the cap– junction of OEE and IEE
Formation of membrane preformative and DEJ
Basement membrane renamed membrane preformative during apposition
MP disintegrates after attachment of odontoblasts and ameloblasts
Mantle dentin and aprismatic enamel form the DEJ
What does HERS/epithelial cylinder form from?
The cervical loop
What does the epithelial diaphragm form from?
Forms from HERS inferior rim folding medially
Determines shape, size and # of roots
At the site of the apical foramen
When do cell rests of Malassez form?
WHen HERS breaks down, initiating cementum formation
What are accessory canals?
Parts of HERS break down too soon, before root dentin forms
These breaks become innervated with BV and nerves
Which germ layer does dental lamina form from?
Basal layer of oral epithelium
Derived from ectoderm
Lines stomodeum
When does the dental papilla form?
During cap stage from ectomesenchyme tissue
Gives rise to dentin and pulp
Fills concavity of the cap
Determines what type the tooth will be (inductive capabilities)
Cap stage associated cells and structures
Cells: Stellate reticulum, OEE, IEE, mesenchymal cells
Structures: Enamel knot***, cervical loop, dental papilla, dental follicle
Bell stage associated cells and histological changes
Cells: stratum intermedium, preameloblasts, preodontoblasts
Histological changes: OEE squamous to low cuboidal, IEE squamous to tall columnar (form preameloblasts). Dental papilla increase in size, dental lamina starts disintegrating forming cell rests of Serres
Epithelial-mesenchyme interaction
Dental papilla stimulates IEE to form preameloblasts- determines morphology
Enamel organ- preameloblasts stimulate dental papilla to form preodontoblasts
Associated cells of apposition stage
Odontoblasts form
Ameloblasts form
Stellate reticulum collapses
What forms from the termination of amelogenesis?
REE forms and triggers termination of amelogenesis (forms on formed enamel)
WHat is Nasmyth’s membrane?
Primary cuticle forms between REE and formed enamel
Participates in early formation of DGJ
Secreted by post-ameloblasts
What is the current theory on dentin hypersensitivity?
Hydrodynamic theory- Change in tissue fluid pressure in dentin tubule gets transmitted to the pulp/nerve fibers
Causes of dentin sensitivity
Thermal- cold/ice/hot
Mechanical- brushing/instrumentation/hand or ultrasonic
Dehydration- drying w/ air or gauze
Chemical- food (sweet/sour); composite restorations, vital bleaching
Biofilm/Plaque
What is primary dentin?
All dentin that forms prior to completion of root
Mantle dentin
Circumpulpal dentin
What is secondary dentin?
All dentin formed after root formation or primary dentin
Similar to circumpulpal dentin
Naturally firming, not caused by trauma
What is tertiary dentin?
Reparative/reactive dentin
Forms in response to caries or trauma (abrasion, abfraction)
Can be regular or irregular in formation
The higher the severity of trauma, the more irregular the formation
What are dead tracts?
Caused by caries and/or trauma
Area of empty dentin tubules beneath a carious lesion where odontoblasts have died and not laid down sclerotic dentin
Metabolic disturbances in dentin
Lines of Von Ebner/ Imbrication Lines
Contour line of Owen
Neonatal line
What are lines of Von Ebner?
Marks daily deposition of dentin (growth rings)
What are contour lines of Owen?
Wide rings caused by a metabolic change (fever, dehydration, medication etc)
Individual could be sick or something that happened to that person that day
What are neonatal lines?
Metabolic shock of birth
Accentuated by lines of Owen
What are Tome’s processes? What do they do?
Short blunt process at the very end of ameloblasts.
Creates rod space that will back-fill with enamel matrix to form prism
Forms as ameloblasts move away from enamel
Metabolic disturbances in enamel
Daily imbrication lines
Striae of Retzius
Neonatal Line
Daily imbrication lines in enamel
Like lines of Von Ebner
Perpendicular to enamel rods
Daily production of enamel
What are Striae of Retzius
Like lines of Owen in dentin
Overlapping areas on labial surface
What are perikymata?
Shallow grooves between striae of Retzius
What forms neonatal lines in enamel?
Metabolic shock of birth
Accentuated Striae of Retzius
What does the ASA block anesthetize?
Incisors and canines
What does the MSA block anesthetize?
Premolars and MB root of max 1st molar
What does the PSA block anesthetize?
DB and P root of max 1st molars, 2nd molars and 3rd molars
What does the IA block anesthetize?
All mandibular teeth (incisors and molars) and lingual gingiva
What does the BN/Long buccal block anesthetize?
Posterior buccal gingiva
What does the MI/mental incisive block anesthetize?
Mandibular anteriors, premolars and associated gingiva
Deciduous universal tooth numbering
Maxillary teeth= A through J
Mandibular teeth= K through T
Permanent universal tooth numbering
Maxillary teeth= 1 through 16
Mandibular teeth= 17 though 32
Cells in pulp
Fibroblasts Odontoblasts*** Mesenchymal cells Pericytes/Rouget cells Dendritic cells Macrophages Extravasated WBC's***
What are dystrophic calcifications?
Calcifications in roots canals
Calcified collagen fibers surrounding nerve fibers and BV
What are focal calcifications?
Pulp stones
Calcified bodies, irregular to round in shape
May lodge in or over the root canal
What are the 4 pulp layers/zones?
Odontoblastic layer
Cell Free Zone
Cell Rich layer
Pulp Core
What is the 1st pulp zone?
Odontoblastic layer- peripheral layer- highly mitotic
Formative, protective, sensory
What is the 2nd Pulp zone?
Cell Free Zone- Fewer cells- increased number of mesenchyme cells during dentinogenesis
Sensory, nutritive
Contains nerves, BV, collagen and ground substance
What is the 3rd Pulp Zone?
Cell Rich Zone- increased cell content
Fibroblasts, mesenchyme
Formative, nutritive, sensory
Contains nerves and BV
What is the 4th Pulp zone?
Pulp Core- bulk of pulp
Formative, sensory, nutritive
Where is Rashkow’s Plexus?
Deep to the cell rich zone
What provides blood supply to the teeth?
Cell rich zone- majority through pulp
Maxillary artery
Max= superior alveolar artery
Mand= inferior alveolar artery
Pulpal BV branch off PDL vessels
What innervates the teeth?
Trigeminal nerve
Max= foramen rotundum- ASA, MSA, PSA
Mand= foramen ovale- IA, BN, M/I
Cellular vs Acellular cementum
Acellular covers the entire root- no cementocytes
Cellular covers acellular cememntum on the apical 1/3 of root- contains cementocytes, house canaliculi in lacunae for nourishment
Helps maintain occlusion
What are intrinsic cementum fibers?
NOT PDL FIBERS
Produced by cementoblasts
Contained in cementum
Run parallel to DCJ
What are extrinsic collagen fibers?
Sharpey’s fibers (PDL fibers)
Produced by fibroblasts
Terminal ends of PDL/principle fibers trapped in surface of cementum
What are the resorption properties on cementum?
More resistant to resorption because it is avascular–> fewer cementoclasts/odontoclasts
Allows tooth movement w/o destroying the root
CEJ variations
Meets enamel- 30%- smooth
Overlaps enamel- 60%- convexity
Falls short of enamel- 10%- concavity
What is calcium hydroxyapatite for cementum derived from?
Mantle dentin
What are the cells of cementum?
Cementoblasts- form cementum matrix
Cementocytes- Mature cells (cementoblasts trapped in calcified matrix)
Cementoclasts- Resorb cementum
Why does continual formation of cementum occur?
Increases PDL space/width
Maintains root length
Maintains occlusion due to attrition
- A decrease in cementum may constrict the apical foramen and blood supply
Types of Bone
Cancellous Bone (spongy) Compact Bone (dense)
What is cancellous bone? Types of lamellae?
Spongy bone- large, open marrow spaces
Types of lamellae- trabeculae (thick) and spicules (thin)
What is compact bone? Types of lamellae?
Dense bone- smaller marrow spaces
Types of lamellae: external circumferential, internal circumferential, interstitial, haversian
Trabecullae of cancellous bone
Thick and composed of several layers
Increased number of osteocytes and osteoblasts
What are the 3 types of CT coverings?
Periosteum
Endosteum
Mucoperiosteum
What is periosteum?
Outer fibrous layer is dense CT- attachment point for tendons/muscles
Inner osteogenic layer (next to bone) is mostly osteoblasts and osteoclasts- attachment point for periosteum via extrinsic fibers
What is endosteum?
Lines marrow cavities
Delicate membrane on internal surfaces of bone
What is mucoperiosteum?
Covers hard palate
Outer surface attachment point for masticatory epithelium
Inner surface attaches to periosteum of hard palate
Intramembranous bone formation (head and neck)
Collagen sheath forms–> primary bone forms–> secondary bone replaces primary bone
Intracartilagenous bone formation (long bones)
Primary bone cartilage model forms (Meckle’s)–> Secondary bone forms- entire calcified bone complex is resorbed and replaced
What are resorption bays?
Howship Lacunae
Found on outer surface of bone and membranes
House osteoclasts
What is alveolar bone proper?
Lines alveolus, surrounds root
Contains Sharpey’s fibers
Referred to as: Lamina dura, cribiform plate, bundle bone (perforations for BV, nerves, lymphatics. Very dense, anchors sharpeys fibers)
Attachment point for PDL
Attaches to ABP
Extends from ABP to cementum
Alveolar crest
Free border of alveolus
Follos contours of CEJ
Most coronal portion is interproximal
Most apical portion L/B & P/L
What is supporting alveolar bone?
Supports alveoli and ABP
What are the 2 types of bone that comprise the SAB?
Cortical plate (compact)- B/L/P surfaces
Spongiosa (cancellous)- btw cortical plates and surrounds ABP and alveous
Describe trabecular arrangement of spongiosa. How does this help?
Haphazard arrangement- sparce, ladder-like appearance
Resist vertical forces
Describe the interdental septum
Bony projections that separate adjacent alveoli
Spongy bone covered by ABP
Zuckerkandl & Herschfelds canals
Describe the interradicular septum
Bony septum intervening between roots
Spongy bone covered by ABP
Zuckerkandl & Herschfelds canals
What is the embryonic origin of alveolar bone?
Neural crest cells
Where are osteoblasts of alveolar bone derived from?
Ectomesenchyme/mesenchyme cells of the dental sac
Osteogenic cells
What is the distance of the CEJ to the alveolar crest?
1.8mm
1-2 mm
What are the three words for ABP?
Lamina dura
Cribiform plate
Bundle bone
WHat is lamina dura?
Compact bone that lies adjacent to the PDL
Surrounds tooth socket and provides attachment surface for sharpeys fibers
WHat is the cribiform plate?
Contains holes where Volkmann canals pass from alveolar bone into the PDL
What is bundle bone?
Term for the portion of the alveolar bone that surrounds the teeth and into which the sharpeys fibers anchor themselves.
Also perforations for BV, nerves, lymphatics
Where are Zuckerkandl & Herschfeld canals located? What are they?
Contained in the interdental and interradicular septums
Canals containing BV, lymphatics and nerves
What causes reversal lines?
When osteoclastic activity stops
What is Wolf’s Law?
Ideal tooth movement keeps root & PDL intact
With horizontal PRESSURE, AB resorbs
With horizontal TENSION, AB forms
What are Sharpey’s fibers?
Extrinsic fibers that insert into cementum and AB
Terminal ends of principle fibers
WHat is the function of ground substance?
Acts as a hydraulic system during mastication
What are the principle fiber groups?
Alveolar crest fibers Horizontal fibers Oblique fibers Apical fibers Interradicular fibers
Where are alveolar crest fibers located? What forces do they resist?
Alex of crest to cementum @ cervix of the root
Resists tilting, occlusal, avulsive and rotational forces
Where are horizontal fibers located? What forces do they resist?
Extend from ABP to cementum just apical to alveolar crest fibers- coronal 1/3 of root
Resist tilting and rotational forces
Where are oblique fibers located? What forces do they resist?
Extend obliquely from ABP to cementum just apical to horizontal fibers- mid portion of root
Most resistant to occlusal forces and some rotational
Where are apical fibers located? What forces do they resist?
Extend from ABP to apical cementum
Resist avulsive forces and rotational forces
Where are interradicular fibers located? What forces do they resist?
Multi-rooted teeth only- extend from apex of interradicular septum to cementum of furcation area
Resist tilting, occlusal, avulsive, rotational forces
Where are circular fibers located?
Encircle cervix of tooth in CT of free gingiva and papilla
Where are alveogingival fibers located?
CT of free and attached gingiva to alveolar crest
Where are dentoperiosteal fibers located?
CT of attached gingiva from alveolar cortical plate to cervical cementum
Where are dentogingival fibers located?
CT of free and attached gingiva from cementum
Where are transseptal/interdental fibers located?
Cementum in tooth, in CT of interdental papilla, to cementum of adjacent tooth
Gingival coloration
Coral pink to brown- melanin and BV
Associated structures of gingiva
Free gingiva Gingival margin Free gingival groove Gingival sulcus Junctional epithelium Attached gingiva Interdental papilla
Attachment of ortho/parakeratinized epithelium to CT
Tightly bound, relatively immovable, withstands strong shearing forces and is less permeable
Slower cell turnover
What is basal lamina?
Two cell layers that separate epithelium from CT
What is the attachment mechanism of basal lamina
Occurs via hemidesmosomes
The more the tissue needs to be anchored and stay in place, the more prominent the epithelial ridges will be
Location of attached gingiva
Extends from free gingiva to MGJ and attaches to alveolar bone
B/L/P/L
Concentratuon of rete ridges in free gingiva
Increased concentration of rete ridges
Characteristics of lining mucosa
Nonkeratinized, stratified squamous epithelium
Found in the sulcus, JE, col region, floor of mouth, ventral surface of tongue, soft palate
Characteristics of epithelial rete ridges
Concave, torturous curves of basal lamina that increase surface area contact to CT
Most prominent in masticatory mucosa
Function of gingival ligaments
Supports the gingiva
Characteristics of JE
Forms floor of gingival sulcus
At same level of free gingival groove
Attaches gingiva directly to tooth surface via hemidesmosomes
External separates epithelial cells & lamina propria
Internal anchors to lamina densa
Which are the first teeth to exfoliate?
Maxillary and mandibular centrals
E&F
O&P
6-7 years
Which are the first non-succedaneous teeth to erupt?
Maxillary and mandibular 1st molars at 6-7 years
8 & 9
24 & 25
During which stage does formation of ABP occur?
Eruptive stage
Order of tissue resorption during exfoliation
1st- Cementum
2nd- Dentin & Pulp
3rd- Enamel
Enamel formation vs root formation & maturation
Enamel is fully formed but not calcified until several years after eruption
Root formation occurs during the eruptive stage and aids in eruption
Both finish maturing post eruption
What is the current eruption theory?
Myofibroblasts of PDL exhibit contractile capabilities, pulling tooth in an axial direction
What are the 3 major salivary glands and their secretion
Parotid gland- pure serous
Submandibular- mixed
Sublingual- mixed
Which glands secrete intermittently and continuously?
Major glands secrete intermittently
Minor glands secrete continuously
What are the 3 acinar cell types?
Pure serous TSU- watery thin saliva
Pure mucous TSU- viscous, thick saliva
Mixed TSU- combination secretion
Mandibular condyle CT covering in children
Covered by hyaline cartilage
Mandibular condyle CT covering in adults
Covered by fibrocartilage
Cells of the articular disc
Composed of collagen and elastin
Collagen derived from fibroblasts
Cells of acute inflammation
Presence of PMN’s
More symptoms, pain etc.
Cells of chronic inflammation
Lymphocytes and plasma cells
Less symptoms, pain etc.
Cardinal signs of inflammation
Color change
Swelling/edema
Bleeding and suppuration
Cardinal symptoms of inflammation
Pain
Heat
Loss of function (cant chew)
Which anesthesia blocks must be administered to cover the maxillary 1st molar?
MSA and PSA
