FINALSTUDY GUIDE Flashcards
what is the average diameter of the apical foramen?
.3-.6 mm
what canal of the MD molars is the biggest?
the distal of the MD molar
what canal of the MX molar is the largest?
the palatal has the largest diameter
why does the pulp become smaller with age?
constant slow formation of dentin
this dentin happens after the tooth maturation, is slower, and is less symmetrical?
secondary dentin
what is tertiary dentin?
resposne to injury, caries, restoration, trauma. it’s the least organized and localized formation
subdivided into reactionary- tubular dentin continuous with original dentin and is formed during ODBI
and repartive-
is repartive tertiary dentin tubular or atubular?
atubular. formed by new ODBI because the original were killed with caries.
where do lateral canals usually form?
apical 1/3
best pulp capping material with a diagnosis of reversible pulpits?
calcium hydroxide
what is the function of the odontoblast cell body?
secretory cell. MAKES PROTEIN! lies aubadjacent to the unmineralized dentin matrix (pre dentin)
what is the function of the cell process?
makes dentin a living, sensate structure. SECRETES! extends outward for a variable distance through the dentinal tubule.
The process of LIVING
what is the most common cell type in the pulp?
fibroblasts
purpose of the fibroblasts in the pulp?
produce and maintain collagen and ground substance after pulp structure during disease
what is the most prominent immune cell in the dental pulp?
dendritic cells- they are the antigen presenting cells
what is a free pulp calcification?
it’s surrounded by pulp tissue!
what is an attached pulp calficiation?
it’s continuous with dentin
what is embedded pulp calcificaiton?
it’s surrounded by dentin (tertiary usuallY)
what are diffuse or linear deposits with neuromuscular bundles?
usually seen in aged, traumatized, or chronically inflamed pulps. Not pathological or symptomatic.
T/F the pulp has arterioles that eventually branch into a rich capillary network in the subodnotnblastic plexus?
true
what kind of dentin is laid down as we age?
peritubular
what is inter-tubular dentin?
between the tubules.
In health, what is the width of the periodontal ligament?
.15 mm for young
.21 mm for old
A variant of asymptomatic apical periodontitis, representing an increase in trabecular bone in response to persistent irritation
condensing osteitis
where is condensing osteitis usually found?
in the mandibular posterior teeth.
can occur in the apex of any tooth though
T/F
Condensing osteotis is always associated with pain
FALSE. depends if it is associated with pulpits or plural necrosis. It may or may not be sensitive
What is the difference between condensing osteitis, and scerlotis bone?
condensing osteotis is associated with pathologic process
What distinguishes AAA?
SWELLING and sometimes elevated temp.
What is the purpose of the percussion test?
tests for inflammation of the PDL. this could be pathologic or iatrogenic. **be sure to check for bruxism and hyper occlusion
Purpose of transiluminaton in pulp testing?
helps to identify longitudinal crown fractures because the fx will not transmit light!!!
What is the principle threat to the pulp when trying to use pulpal protection?
caries! second most is during the treatment of dental caries.
Why might LA be problematic for the pulp?
think of the ischemia from the EPI! Healthy pulps can withstand ischemia for one hour or more
T/F
It is a good idea to DESICCATE the dentin or use harsh chemicals?
super false….that’s a terrible idea. Dry cavity preps with cotton pellets and short blasts of air vs. harsh chemicals.
T/F
The diameter and density of dentinal tubules increase w/ cavity depth.
TRUE
how much dentin is ideal to protect the pulp from most irritation?
1 mm
T/F
Microorganisms present in dental caries are the MAIN SOURCES OF IRRITATION OF THE DENTAL PULP AND PERIRADICULAR TISSUES.
TRUE
why do we like nickel titanium instruments?
• Nickel-titanium instruments are more flexible and adapt more readily to fine, curved canals but have no advantage over stainless steel files in irregular canal spaces.
what has a better cutting efficiency?
SS
what is a disadvantage of the increased flexibility of NiTi?
you cannot preserve the file.
what is the size of the tip of a #25 file?
.25 mm
tip size of #50 = .5 mm etc.
Why might we chose a 21 mm instrumetn vs. a 31 mm instrument?
shorter= more operator control and easier access to poster teeth iwht a limited opening impairs access.
what are the 3 different file lengths?
21mm, 25 mm, and 31 mm
What does it mean when we say we have a .02 mm taper?
this means the the file diameter increases by .02 mm for each running gym of file length.
if .04 taper, that means the file diameter increases by .04 mm every 1 mm of the length.
SO the tip is the same, it’s just the ratio that is different
what is the purpose of the barbed broach?
stainless steel instruments with plastic handles. barbs enable and remove canal contents and should neither bound in the canal or aggressively forced around a canal curvature.
advantage of Nickel titanium engine files vs. stainless steel?
engine driven = better control in small curved canals and they don’t have a cutting END.
what are some common defects we see with the hand file?
unwinding of the flutes, roll up of the flutes, tip distortion, corossion
what do we use for lateral condensation?
the spreader!!! stiff and made of annealed SS
you do have niTi spreaders though too
what kind of cleaning should we employ for the sharp edge instrument?
DRY heat. 160C for 60 mins
Do we auto clave the files?
no, used just once. The other instruments are autoclaved.
where is the roof chamber approximately in molars?
it’s at the level of the CEJ
T/F
When two canals occur in the root they tend to be more oval.
True
T/F
lateral canals supply collateral circulation and therefore contribute little to pulp function and probably represent an anomaly that occurred during root formation
FALSE do not
T/F
lateral canals must be cleaned and obturate?
no.
these are not important for the success of root canal
how far away is the apical foramen from the true apex of the tooth?
.5-1 mm
what is the prognosis of a lingual groove?
often not good…results in a deep narrow periodontal defect that occasionally communicates with the pulp
where are dens in dent usually found?
also called dens invaginatus- most common the max lateral from folding of the enamel organ during proliferation.
often results in an early pulp oral cavity communication = root canal
where do we see dens evaginatus?
often seen in the mandibular premolars. those with asian, NA, or hispanics.
Looks like a small tubercle
Describe WL?
TThe WL is defined as the distance from a predetermined coronal reference point to the point that the cleaning and shaping and obturation should terminate.
T/F
Take off the rubber dam with each radiograph?
false- that’s why it’s plastic!
what is a sodium hypochlorite accident/
when he sodium hypochlroite extends beyond the apex
What in the heck is the smear layer?
amorphous, irrgeular accumulation of organic pulpal material and inorganic
how thick is the smear layer?
1-5 micrometers
Do we want to keep or remove the smear layer?
get rid of it! if the pulp is necrotic, we want to remove this with acids or other chelating agents.
we can use 17% EDTA for ` minute followed by rinse with NaCOl
HOWEVER…no consensus here. You can just use NaOCL
Where are the “danger” zones?
danger zones are located in the frugal area of molars between canals and the furcation.
This area often has less dentin between the canal to the outer surface of the root.
Root concavities are a big risk too
