510-9 Flashcards
Define: Distal, Mesial, Labial, Buccal, Facial, Lingual
Toward: Molars, Incisors, Lips, Cheeks, (lips + cheek), Tongue
Define Occlusal
Top of a tooth - portion that touches another tooth.
The organic material in enamel is composed of what and comprises what percentage of overall composite?
Type I collagen / Comprises only 0.5% of enamel.
What is the main component of enamel?
Hydroxyapatite (Calcium Phosphate Hydroxide)
Ca10(PO4)6(OH)2
What can too much Fluoride cause?
Fluorosis. It can interfere with normal enamel production and create divots on the surface of teeth creating a mottled look.
Why do different acids produce different textures on enamel.
Orientation of crystals to the acid will erode some parts of enamel preferentially.
Is the Dentinoenamel Junction (DEJ) smooth?
No. It is jagged and resists shearing forces.
What are 3 types of enamel defects?
Enamel Lammela (dark lines running all the way through enamel)
Tufts (smaller crack-like formations close to the DEJ
Spindles (small radiating imperfections at the DEJ)
What does the odontoblast process connect?
The Odontoblast to the DEJ
What substance makes up most of the tooth?
Primary Dentin
What are the 2 types of tertiary dentin?
Reactionary (laid down by existing odontoblasts)
Reparative (laid down by newly differentiated odontoblasts)
What type of fibrils surround a developing odontoblast process?
Type I collagen fibrils.
What can lead to a dead dentinal tract?
Odontoblast death
Where is the Dentin-Pulp complex innervated?
By nerve loops that travel into the predentin originating in the Nerve plexus of Raschkow.
What is one problem with direct innervation theory.
Before Raschkow and loops develop in teeth they can already feel pain.
What’s a problem with Odontoblast as receptor theory?
In Vivo measurements suggest membrane potentials cannot propagate a neural signal.
What is the best theory of dentin sensitivity?
Hydrodynamic model suggests droplets oozing out of dentin after exposure “pull” (via tubules) on Plexus of Raschkow and surrounding innervations.
In composition cementum is most similar to:
Bone
What is the most important type of cementum?
Anchorage cementum. This is acellular and has extrinsic fibers.
Where are cellular and acellular cementum located?
Cellular is at the root of the tooth and has a role in repair and movement.
Acellular is above and serves as an attachment to the dentin.
Describe AEFC vs CIFC
acellular extrinsic fiber cementum - no nuclei
cellular intrinsic fiber cementum - nuclei
What is the principle tissue for tooth attachment?
Acellular Extrinsic Fiber Cementum
this is called extrinsic because the attaching fibers come mainly from the fibroblasts of the periodontal ligament
Where is cellular intrinsic fiber cementum found?
pre-molars and molars
involved in repair
Is abutment or overlap the most common type of cementoenamel junction.
Overlap (60%)
10% cases have too little cementum @ junction
