Endo Test 1 Flashcards
Endo is concerned with…
MORPHOLOGY, PHYSIOLOGY, PATHOLOGY of PULP and PERI-RADICULAR TISSUE
Apical periodontitis
Detected by peri-radicular radiolucency – INCREASED OSTEOCLAST ACTIVITY
NSRCT is to remove the __ and __ of microorganisms to pulpal and periradicular space
presence and access
What three factors determine how fast Apical Perio heals?
Chemomechanical debridement and restoration, endo pathogens, host factors
What two cytokines released by macrophages play an important role in bone resorption
IL1 beta and PGs
5 things in NSRCT
Diagnosis coronal access instrumentation obturation final restoration
Diagnosis is made up of 3 things
history (med and dent)
classification of pulpal and periradicular disease
treatment plan
how many positive signs or symptoms do you need before starting RC treatment?
TWO
What are the 3 goals of coronal access
straight line access
conserving tooth structure
unroof pulp chamber and remove pulp horns
law of centrality
pulp chamber is always in the CENTER of the tooth
it is at the level of the CEJ
Law of concentricity
walls of pulp chamber are concentric to the external surface of the tooth at the CEJ
Same amount of tooth lies between the outside and the pulp chamber
Law of CEJ
CEJ is the most consistent, reproducible landmark for locating the pulp chamber
CEJ is easy to see, even on heavily restored teeth
roof of pulp chamber at CEJ usually
law of symmetry I
EXCEPT FOR MAX MOLARS – orifices are equdistant from MD drawn on camber floor
Law of Symmetry II
Except for MAX MOLARS – the orifices lie on a line PERPENDICULAR to the MD line
Law of color change
Color of the floor of the pulp chambers is darker than the walls
Law of orifice location I
orifices located at junction of wall and floor
Law of orifice location II
Orifices are located at the terminus of the developmental fusion lines
**Champagne bubble test - helps you locate orifice
what are the 2 major goals of instrumentations
cleaning and shaping
what are some chemicals you can use to clean
NaOCL - irrigation
Ca(OH)2 - between appointments
What kind of shape do you want to achieve through the shaping stage
continuously tapering conical shape from apical to coronal ends of the RC system
What is the goal of obturation
create a fluid-tight seal int he entire length of the RD system and to entomb any residual pathogens
Coronal seal
temporary and final restoration
prevent microleakage
What are some indications for NSRCT
Irreversible pulpitis pulpal necrosis hyperplastic pulp prosthetics excessive supraeruption interna/eternal resortpion endo --> perio
CONTRAINDICATIONS to NSRCT
tooth is unrestorable insufficient perio support massive root resorption non-strategic tooth canal instrumentation not practical
When do you evaluate NSRCT after you do it
6 months after
then yearly after that
how do you know you were successful?
tooth is asymptomatic
tooth si functional and firmly seated in alveolus
soft tissue is normal
radiographs show normal lamina dura and no more PA radiolucency
How do you know NSRCT was unsuccessful
symptomatic tooth
soft tissue – sinus tract plus palpation
PA radiolucency still there
Successful endo depends on
effective pain control and anxiety control
what is endo pain secondary to
inflammatory mediators on nociceptors
What are the THREE Ds to control endo pain
diagnosis
definitive dental treatment
drugs – there are 3 drug classes that can act at CNS, act on axons, act on the inflammatory mediators
after you do NSRCT, how does the root grow back
SCAP – stem cells from apical papilla
Pulp is from what origin
mesenchymal
pulp is mostly
CT – highly vascularized and innervated
what are the functions of pulp
inductive formatie nutritive sensory protective
Pulp horns in incisors are
located MD
pulp horns in post teeth correspond to
cusp tips
pulp chambers tend to occuppy
crown center
dimensions of pulp chamber depend on
shape of crown and trunk
“pulp cavity” is divided into what two things
pulp chamber and root canal
coronal part and radicular part
what kind of curve to most root canals have
FL – so a curved canal is often undetectable on a facial projection radiograph
wide roots tend to have
more than one canal
root canal extends from what to what
orifice to apical foramen
the shape of the pulp system reflects
the surface outline of the crown and root
Weine canal classification - TYPE 1
one orifice - one canal - one foramen - (1-1)
Weine canal classification - TYPE 2
two orifices - two canals - one foramen (2-1)
Weine canal classification - TYPE 3
Two orifices - two canals - two foramina (2-2)
Weine canal classification - TYPE 4
one orifice - two canals - two foramina (1-2)
What are somet things that can alter the internal anatomy of a root
age, irritants (that stimulate increased dentin formation – like caries, perio disease, etc)
calcifications
internal resorption - uncommon and not extensive
the apical foramen is usually…
NOT at the true anatomic apex of root
Apical constriction
if present, it is not radiographically visble and usually not detectable with tactile sensation
the apical constriction is usually how far away from the apical foramen
0.5 to 0.75 mm away from the apical foramen
the apical foramen is usually how far away from the anatomic apex?
3mm
Dens invaginatus
max laterals
infolding of enamel
leads to variation in root and pulp anatomy
could be a source of irritation
dens EVAGINATUS
seen in mand premolars
small tubercle on the occlusal surface – has pulp
if the tubercle fractures, there is pulp exposure and it can lead to pulp necrosis
source of where bacteria enters
where do you see high pulp horns
mesio buccal of first molars
where do you see lingual groove
max laterals
can lead to a deep narrow perio defect which can have pulpal communication
Dilaceration
complex root curves
info about the max central
triangular access 1 canal at apex 22mm long root root is broad BL labial/facial curvature apically
max lateral
Triangle – oval access
1 canal at apex
Distsal curved root at apex
Max canine
oval access
LONGEST TOOTH - 26 mm
1 canal at apex
distal curved root at apex
Max first PM
oval access -- wide FL 1 canal - 26% 2 canals - 69% 3 canals - 5% mesial concavity on crown and root at CEJ
Max 2nd PM
75% - 1 canal at apex*
24% - 2 canals at apex*
1% - 3 canals at apex*
Max 1st molar
Triangle access - base toward facial and apex toward lingual -- situated more on the mesial side of tooth --the 2 MB canals are 1-3 mm apart MB root: 82% has one canal; 18% has 2 DB root - 1 canal Palatal root - 1 canal
Max 2nd Molar
MB root - 88% has 1 canal; 12% has 2
DB root - 1 canal
Palatal root - 1 canal
the palatal root is facially curved in…
55% of first molars
37% of second molars
Mandibular incisors
centrals - 3% have 2 canals
laterals - 2% have 2 canals
Mandibular canine
oval access – widest FL access
6% have 2 canals
Mand 1st PM
oval acces - wide
74% have 1 canal
25% have 2 canals
what is different about mand PM crown?
crown is at 30 degree angle to root
Mand 2nd PM
oval access - wide FL
97% have 1 canal
3% have 2 canals
Mand 1st molar
81% of mesial root has 2 canal orifices and 61% of those have 2 canals that exit the apex
Distal root – 22% have 2 canal orifices and 15% of those heave 2 canals that exit the apex
mand 2nd molars
Mesial root - 64% have 2 canal orifices and of that 35% have two canals that exit the apex
distal root - 7% have 2 canal orifices and of that 5% have 2 canals at the apex
so the distal root of mand 2nd molar is usually 1 canal orifice and one canal at apex
what is a radix paramolaris
additional FACIAL root
Radix entomolaris
additional LINGUAL root
Principles of endo access are…
removal of all defective restorations and caries before entering the pulp
removing unsupported tooth structure
create access cavity walls that do not restrict straight or direct line passage of instruments tot he apical foramen
where do you want your straight line access to reach
apical third of canal or where the initial curve of the canal begins
proper access allows for three thing:
effective irrigation
cleaning and shaping
quality obturation
what are the two safe ended burs
endo-z and tapered diamond
what can you use the endo explorer to do
locate orifices and evaluate straight line access
what is the major etiologic factor of pulpal disease
bacteria
Bacterial-induced inflammation and necrosis of pulpal tissue.
–need to remove presence and access of bacteria
what are portals of entry for bacteria into pulp
attrition or other trauma caries failed restoration -- microleakage anachoresis- bacteria gather in one spot perio--> endo connections
what kind of bacteria invade pulp
polymicrobial = 5-8 diff types
the percent of obligate anaerobes increases over time
more G- than G+
Why does necrotic pulp favor anaerobes?
low O2 tension
rich in Polypeptides and AA
favors commensal interactions among microbes — one bacteria’s trash is another’s treasure
successful NSRCT involves
disruption and removal of bacteria
AP is associated with what bacteria
Prevotella - pain and sinus tract too
Porphyromonas - pain and sinus tract too
Fusobacterium
Peptostreptococcus
Not all infection is caused by bacteria…
Yeast. Herpes. HIV also involved
if there is bacterial colonization, are you INFECTED?
NO. most of thse bacteria are NORMAL FLORA.
when can you call it INFECTION
when there is DAMAGE to the host with emergence of clinical signs and symptoms
where does most of the pathology of infections come from
release of bacterial compound ( LPS, capsules, enzymes etc)
Activation of HOST’S cytokine network
Destruction of host cells and microbes
How does the pulp respond to infection?
Non-specific: PMNS –> liquefactive necrosis –> abscess - or macrophages
Specific immune response: TH > Ts > Plasma
Secondary dentin formation
Vital pulp can help stop growth of bacteria.. but necrotic pulp is not resistant to infection
What are the major cell types in peri-radicular lesions
Macrophages, lymphocytes (T>B), plasma cells, PMNs, NK, eosinophils, mast cells
This infiltrate can comprise ~50% of all cells
increased osteoclast activity leads to apical perio… through what?
IL 1 - beta
PGs
What if bacteria are present during obturation/
success drops from 94% to 68%
What is so special about Enterococcus faecalis
33-60% of NSRCTs have E. Faecalis
How far can microbes grow into dentinal tubules in 14-21 days?
300-400um
this is why uthscsa does a “crown down”
what is the best method of cleaning?
cleaning and shaping (instrumentation)
with 0.5% NaOCL and
Ca(OH)2 for 1 week
If there is pulpal necrosis with AP present, there is…
> 90% chance of intraradicular infection
what are some techniques to reduce bacteria
Rubber dam
Chemomechanical debridement (modified crown-down, larger file size, copious NaOCl irrigation)
Inter-appointment medicament (Ca(OH)2 has best antibacterial effectiveness)
Quality of obturation
Seal of temporary and final restoration
what are some properties of an ideal irrigant
removes debris antimicrobial dissovles organic tissue removes smear layer disinfects areas not accessible to files lubcricates files -- so you don't have separation non-toxic not altered by dentin
Rank the irrigants from most to least useful
4% NaOCl > 2.5% NaOCl > 2% chlorhexidine > 0.2% chlorhex > EDTA > citric acid > 0.5% NaOCl
do EDTA to remove smear layer
When do you prescribe abx?
systemic involvement: lymphadenopath, fever, malaise etc
Pt has compromised immune system: disease or drugs
if the signs/symptoms are rapidly increasing
if there is involvement of an anatomic danger zone
when you do use abx.. you should
check up on PT every 24 hrs
use loading doses
Thee are 3 most common strains of pathogens
eubacterium (91 strains)
peptostreptococus (65 strains)
black-pigmented bacteroids (30 strains)
ALL ARE SUSCEPTIBLE TO PENICILLINS
what percent of the bacteria are susceptible to amoxicillin + clavulanic acid
99% – it is the BEST
augmentin
what is the worst abx?
metronidzole – only 42% are susceptible
list the abx in order of best to worst
amox + clavulanic acid > clindo > amox = clarithromycin > penicilin > metronidzole
3 stages of odontogenesis
Bud –> cap –> bell –> eruption
when is the enamel knot seen?
starts proliferating at cap stage – it is where the CUSPS or incisal edge will be
where are the number of cusps defined
bell stage
As the tooth erupts, there are NO MORE AMELOBLASTS.. only…?
odontoblasts which persist though life
Hertwigs epithelial root sheath
epithelial origin
communicates with the mesenchymal stem cells
enamel knot determines crown shape
what determines root shape
hertwig’s epithelial root sheath
what are some cells found in the pulp
Fibroblasts Odontoblasts Dendritic Cells PMNs (neutrophils and macrophages) Lymphocytes Endothelial Cells and Neurons Mesenchymal (Stem) Cells
what is the most numerous cell in the pulp
fibroblasts
what does fibroblasts make>
type 1 and 3 collagen
it degrades collagen fibrils (turnover)
and has secretory function – growth factors
what is the most specialized cell in dental pulp
odontoblasts
– make and sescrete DENTIN
makes type 1 collagen and proteoglycans for the ECM
secretes growth factors
believed to be able to detect antigens
what growth factors do fibroblasts secrete
NGF and NPY
what growth factors do odontoblasts secrete
dentin sialoprotein
DPP
what is the ultimate APC>
dendritic cell
highly specialized immune cell
similar to Langerhans cell in skin
class 2 APC
presents it to T cells via MHC II
Macrohpages and neutrophils
move toward a chemokine [] gradient
has APC activity
can squeeze into dentinal tubules
releases inflammatory mediators – IL1 and TNF alpha
which is the regulatory T cell
CD 4
T HELPER
which is the effector t cell
CD 8
CYTOTOXIC T CELL
what makes up the ECM
water GAGs Type 1 and 3 collagen Non-collagenous proteins ----tenascin and fibronectin
what does fibronectin do
Substrate adhesion glycoproteins
Involved in the attachment, spreading and migration of cells
why is the pulp considered MICROvascularized
the biggest artery that enters is an arteriole
the biggest vein that exits is a venule
what is a C fiber
low conducting
THROBBING PAIN
dull ache
typical linflammatory pain
what is an A-delta fiber
sharp and quick pain
dentinal HSR
fluid moving up and down to cause a delta to go off
describe the pathosis in periradicular tissue
Breakdown of bone, PDL and possibly cementum
Loss of cementum may lead the root susceptible to resorptive processes
Periradicular lesion heals with successful Endo TX, if lesion is of endodontic origin.
what are the biologic objectives of cleaning and shaping
Progressively reduce the number of viable bacteria
Remove all tissues and debris
Avoid irritation of the periradicular tissues
what are the MECHANICAL objectives of cleaning and shpaing
Achieve a continuously Tapering Cone Shape
Smooth Canal Walls
Development of an apical stop (matrix)
Avoid Iatrogenic Preparation Errors
what are the 3 steps to cleaning and shaping
Preliminary Crown-Down (pre-flaring of the initial 2/3)
Final Crown-Down
Apical Preparation
what do you use when you crown down
shape root canal system
use different TAPER but SAME SZE
k3
25mm at tip – but various tapers
what are the goals of PRELIMINARY CROWN DOWN === step 1
enlarge canal orifice
achieve straight line access to apical 1/3
gross debridgement of coronal 1/3
What are the goals for the FINAL crown down —— step 2
improve line access to apical 1/3
maintains a glide path into the apical 1/3
gross debridement of the whole root canal system
3rd step - final apical prep
final debridement of apical 1/3
creation of an apical stop (matrix)
how do you get the EWL?
subtract 1mm from the canal length
in the final crown down, what taper K3 file do you have to reach the working length with?
0.04 taper
what provides sensation to pulp
V2 and V3
what are the chemical properties of gutta percha
Soluble in chloroform and xylene
Slightly soluble in eucalyptol
Insoluble in aqueous solutions
what are the biologic properties of gutta percha
Minimally irritating to tissue
Non-biodegradable
Easily sterilized
the master cone is..
tapered
ID’d by numbers - 30, 35, 40 etc
the non-standardized cone is
not tapered – ID’d by name: fine, extra fine, med fine etc
why is gutta percha better than silver tips?
gutta percha adapts to canal walls
what does the thermafill carrier do
combines the properties of gutta percha and silver tips
WHAT ARE THE EFFECTS OF EDTA
Softens dentin. Distinct antimicrobial properties. Moderately irritating. Suitable as irrigating agent. Removes smear layer. Demineralization proportional to time. Partial demineralization.
what is cavit
most commonly used temporary sealer
but don’t use in vital teeth because it needs water to set??
it dehydrates the dentin and causes more pain to PT
use only on non vitals
intermediate restorative material (IRM)
does NOT need water to set
a standard K file has
16 mm of screw area
25 mm length total
when do you use a barb broach
NOT IN A NARROW OR CURVED CANAL
only use for Gross tissue removal from the root canal space
Pulpectomy Debridement
K# profiles have a
onstant tip size and varying taper
the colored ones… have
constant 0.04 taper but varying tip size
what ist he largest k file we use
20
what are the non-cellular defenses of pulp
outward fluid movement
tert dentin
AV shunts
what are the cellular mechanisms of defense for pulp
tert dentin
robust immune response
what kind of pressure is in pulp from fulid movement
positive pressure
outward movement
tert dentin
body’s own restorative material
can be reactionary or reparative
less tubular than reg dentin
makes a hard tissue barrier – dentin bridge
bacterial insult to pulp results in what three things
direct cellular damage
acute inflammatory response
chronic inflammatory response
what is allodynia
reduced threshold – something that should not be painful is painful
what is hyperalgesia
increased signaling – amplifies noxious stimulus
when there is an inward flow of noxious agents…
there is inflammation
then increased intra-pulpal tissue pressure
then outward flow of dentinal fluid
which REDUCES ITHE INWARD FLOW OF NOXIOUS AGENTS!
once you have carious exposure, the chances are
SLIM JIM.
do not perform a direct pulp cap of carious exposed teeth
the master cone for gutta percha should be…
fitted in a dry canal
the master cone of gutta percha should be what when you withdraw it
slightly resistant
does the master cone extend to the working length?
yes
how do you confirm that the apical fit for the master gutta percha cone is good
radiographic
how do you dry the canal
sterile paper points
how do you pick a master cone size
same size as master apical file
set it to the working length
a correct fit gutta percha cone should
be at the WL
slightly resist removal
what if the master cone does not fit
inser the MAF again and make sure it goes down to the correct WL
clear the apex with a 10 file
irrigate and reinsert the master gutta percha cone to the WL or select another gutta percha cone of the same esize
what if you don’t feel resistance?
the final prep is larger than originally believed – operator error
test a larger cone then
only use the larger cone if it goes all the way down to the WL
what if the new master cone feels resistant but it doesn’t reach the WL
you have to go back with the Profile and use one size larger than the origianl cone tested
How does one know when the root canal sealer is properly mixed?
When there is a dense, homogenous, smooth, creamy mass which when the spatula is raised three fourths(3/4) to One(1) inch from the mixing slab, the string of sealer holds 4-5 seconds before breaking
How do you coat the canal walls with sealer
choose a profile instrument 2 sizes smaller than what your MAF was and set it to your WL and coat it with sealer
when do you use a counter clock wise rotation
straight canal when sealing canal
when do you use a wiggle motion when sealing canal walls
curved canal
WHAT DOES “LATERAL CONDENSATION” OF GUTTA PERCHA MEAN?
using spreaders and plungers to fill the root canal system
when do you use a yellow FF spreader
small canals
when do you use a red MF spreader
medium canals
when do you use a F blue spreader
large cnaals
how far from the WL do you need to be when you do lateral compaction
1-2 mm
choose an acessory cone that matches the spreader size you chose
CAVIT can only be used with
non vital teeth it needs water and it will pull water from dentin and dehyrate it and cause more pain if the tooth is vital
