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287 Cards in this Set

  • Front
  • Back
What is the primary function of the dental pulp?
Formation
Which of the following is not a stage of tooth formation?
Basal
From what cells are odontoblasts derived?
Undifferentiated ectomesenchymal
Where does deposition of unmineralized dentin matrix begin and in what direction does it proceed?
Begins at cups tip and progresses cervically
The cervical loop is the location of which of the following?
Where inner and outer dental epithelium meet
What is the first thin layer of dentin that is formed?
Mantle dentin
Epithelial cell rests of Malassez are remnants of what?
Epithelial root sheath
Why are lateral canals clinically significant?
They allow pulp disease to extend to periodontal tissues
What morphological Changes occur to the dental pulp over time?
Overal size of pulp chamber is reduced
The cementodentinal junction (CDJ) is which of the following?
The area where cementum contacts dentin inside the canal
What is the defensive function of the dental pulp?
Odontoblast formation of dentin in response to injury
Which of the following is not a major component of the odontoblast?
Synaptic junction
What cell type is primarily related to the immune system in the dental pulp?
Dendritic
What type of collagen is the most prominent found in the dental pulp?
Type I
Which of the following is not a type of pulp stone?
Floating
Lack of knowledge of pulp anatomy is the ______________ most common cause of treatment failure.
Second
Of the following, which is the best technique to determine if a root contains 2 canals?
Interpreting angled radiographs
The shape of the canal in cross-section is variable but is almost always round in the apical third.(t/f)
First part true, second part false
Multiple canals in mandibular premolars occur most often in which population?
African-Americans
Alterations in the anatomy of the pulp space occur because of which of the following a.age b.resorption c.calcifications
All of the above
Calcifications encountered in the pulp space do which of the following?
Represent additional dentin formation
Which of the following is not associated with the radicular pulp?
Pulp horns
Accessory canals are more common in the apical 3rd, and more common in posterior teeth.(t/f)
Entire sentence is true
Which of the following are true regarding the apical foramen?
The foramen is most commonly located 0.5mm to 1.0mm away from the anatomic root apex
Dens invaginatus (dens in dente) occurs most commonly in which teeth?
Maxillary lateral incisors
The lingual groove defect is (1) found most frequently in maxillary central incisors and (2) has poor prognosis for treatment.(t/f)
Statement 1 is false, statement 2 is true
A C-shaped canal is characterized by which of the following?a.Has complex internal anatomy b.Is most commonly found in the Asian population c.Usually occurs in mandibular 2nd molars d.Should be referred to an endodontist for tx
All of the above
Of the following, which tooth or root is the most likely to have 2 canals?
Mandibular 1st molar mesial root
The lingual root of the maxillary first molar often has a curvature in the apical third to which of the following?
Buccal
Diagnostic radiology is helpful in all of the following except: a.Identifying pathosis b.Determining root anatomy c. Determining pulp anatomy
Determining pulp responsiveness
What are working length radiographs?
Radiographs determine the distance from radiographic apex to a reference point
Radiographs are useful to evaluate the following qualities of an obturation except which of the following?
Sealer thickness
Radiographs are useful in evaluating success and failure at recalls because they do which of the following?
May show failures that often occur without adverse signs or symptoms
The most accurate radiographs are made by doing which of the following:
Using a paralleling device
Use of a paralleling technique may not be feasible when which of the following occurs:
There are maxillary tori
F speed film requires how much less exposure compared to E speed film?
20-25%
What does the con-image shift do?
It assists in identifying superimposed canals
What occurs as cone position moves away from parallel?
Lingual object moves relatively in same direction as the cone
Which is the disadvantage of the cone-image shift?
It may superimpose normal anatomic structures over the root apex
Which of the following is a distinguishing characteristic of a radiolucent lesion of endodontic pathosis?
The radiolucency stays at the apex regardless of cone angulation
A radiolucency of endodontic origin is usually present which what type of pulpal diagnosis?
Necrotic pulp
What is the usual radiographic appearance of condensing osteitis?
Diffuse radiopaque appearance
A mesial projection cone adjustment during working length radiographs is indicated for what?
Maxillary molars with a ML canal
Digital radiography has not been proven to do which of the following?
Provide superior image quality
Which of the following is not a main portal of entry for microogranisms to enter the dental pulp?
Occlusal grooves
Why is there greater dentin permeability near the pulp?
Higher density of dentinal tubules
Exposed dentin provides an unimpeded access for bacteria to enter the pulp.(t/f)
False
What is anachoresis?
Microorganisms transport from blood vessels into damaged tissue
Root canals can become infected through anachoresis.(t/f)
False
Which of the following is not a category of intraradicular infections? A.Primary b.Secondary c.Tertiary d.Persistent
tertiary
The most common microorganisms in primary endodontic infections are
Gram-negative bacteria
Which of the following is not a source of nutrients for bacteria within the root canal system?
Inflamed vital pulp tissue
Which of the following microorganisms are commonly present in large percentages of root canal- treated teeth that present with persistent apical periodontitis, indicative of failed treatment?
Enterococcus faecalis
Gram-positive bacteria have been demonstrated to a.Have higher occurrence in post-instrumentation samples b.Are more resistant to anti-microbial treatment c.Are able to adapt to harsh environmental conditions
All of the above
A direct pulp exposure of a carious lesion is necessary to have a pulpal response and inflammation(t/f)
False
What factor is the most important in determining if pulp tissue becomes necrotic slowly or rapidly after carious pulp exposure and pulpal inflammation?
Lymph drainage
What is necessary for pulp and periradicular pathosis to develop?
Presence of bacteria
Which of following statements is true regarding mechanical irritants?
Operative procedures without water coolant cause more irritation than those performed under water spray
What nonspecific inflammatory mediators are not present when the dental pulp is irritated?
Epinephrine
What cell type associated with immune response is not present in severely inflamed dental pulp?a.T-lymphocytes b.B-lymphocytes c.Macrophages
Odontoclasts
What is the cause of pain during progression of pulpal injury?
Increase of venule vascular permeability
What is reversible pulpitis?
Yields a positive response to thermal pulp testing
What is irreversible pulpitis?
A severe inflammatory process
Which of the following is not a hard tissue change that may result from pulpal irritation or inflammation?a.Calcification of pulp tissue spaces b.Resorption of pulp tissue spaces c.Formation of pulp tissues
Thickening of PDL
What are the signs and symptoms associated with symptomatic apical periodontitis (acute apical periodontitis)?
Marked or excruciating pain on tapping with a mirror handle
What histologic feature differentiates a periapical granuloma from a periapical cyst?
Presence of an epithelial lined cavity
Which of the following is not associated with acute apical abscess? A.Moderate to severe discomfort b.Negative response to electric pulp testing c.Tenderness to percussion and palpation
Intense and prolonged response to thermal stimulus
What factors may impact and influence whether periradicular lesions heal completely or incompletely? A.Size of the lesion b.Blood supply c.Systemic disease
All of the above
What is the most important aid in distinguishing between endodontic and non-endodontic periradicular lesions
Pulp vitality testing
tooth development begins when?
6th week of embryonic life
3 stages of tooth development
bud cap and bell
most important stage of tooth development
bell-major tooth and crown development
what forms enamel
enamel organ
what forms dentin and pulp
enamel papilla
what forms the pdl (cementum, bone, and sharpeys fibers
dental follicle/dental sac
what is made of ectodermal cells
enamel organ
whats made of ectomesenchymal cells
dental papilla and follicle
what cells make:
enamel
dentin
cememntum
bone
sharpey fibers
ameloblast
odontoblast
cementoblast
osteoblast
fibroblast
what forms first, dentin or enamel?
dentin
Explain the differentiation of IEE into forming enamel?
IEE differentiates into ameloblasts, which differentiates ectomesenchymal cells of papilla into odontoblasts which then stimulates secretion of dentin then in turn stimulates ameloblasts to secrete enamel
Hertwig's Epithelial Root Sheath (HERS) is formed from
IEE and OEE
HERS determines?
size and shape of roots of the teeth
when does cementum form?
when HERS fragments, exposing dentin to the dental follicle, allowing cementum to be laid down
what are the Epithelial Rests of Malassez?
remnants of HERS in the PDL
Epithelial Rests of Malassez are involved in forming what?
radicular cysts during chronic inflammation
before dentin is formed, breaks in HERS can form?
accessory and lateral canals
accessory and lateral canals are most common in the?
apical third of the root
accessory and lateral canals can act as passageways for?
bacteria and their by products to communicate btw the PDL and the tooth
HERS stops when
root formation is complete and apical foramen is closed
major apical foramen is located where? apex of the root or coronal to it?
coronal
coronal
apical foramen is how large
0.3-0.6mm (funnel shaped)
narrowest portion of the apical foramen is the?
apical constriction-0.5mm from Major apical diameter
what are the 5 functions of the pulp?
induction
formation
nutrition
defense
sensation
what is the pulp function of induction?
dentin formation induces enamel formation
what is the pulp function of formation?
odontoblast forms dentin. MOST IMPORTANT FUNCTION
what is the pulp function of nutrition?
nutrients to cells through vascularity
what is the pulp function of defense?
macrophages, dendritic cells, lymphocytes, and tertiary.sclerotic dentin is formed
what is the pulp function of sensation?
pain sensation, a delta and c fibers
what is 70% inorganic and 20% organic?
dentin
what makes up of type 1 collagen?
dentin
which type of dentin is formed before the tooth erupts?
primary dentin
what type of dentin forms after the tooth erupts and throughout life
secondary dentin
type of dentin that forms from a pathologic process (caries and trauma)
tertiary dentin
type of dentin that protects pulp from noxious stimuli and injury
tertiaty dentin
what are the types of tertiaty dentin?
reactionary and reparative
type of tertiary dentin formed from the original odontoblasts
reactionary
type of tertiary dentin from new/replacement odontoblasts
reparative
calcified pulp chambers/canals form from
excessive secondary and tertiary dentin
3 layers of dentin are
mantle
circumpulpal
predentin
1st layer of dentin formed is
mantle
mantle dentin is formed from this type of dentin
primary
circumpupal dentin is formed from what types of dentin
primary and secondary
why is it easier for bacteria to infect the pulp?
dentinal tubules are wider and more concentrated at the pulp compared to the DEJ
what type of dentin is located between the tubules?
intertublar
what dentin lines the dentin tubules
intratubular/peritubular
whats more mineralized intertubular or inratubular dentin
intratubular
whats the process of blocking dentinal tubules in response to stimuli and decreasing permeability?
dentinal scleroris
pulp zone next to predentin
odontoblast layer
next to odontoblast layer and contains capillary and sensory nerve fiber plexus (Plexus of Rashkow)
cell free zone
zone contains high proportions of fibroblasts and immune cells
cell rich zone
zone thats the central mass of pulp and contrains vessels and nerves. COMMON CELL TYPE IS FIBROBLASTS
Pulp proper
____are post mitotic and do NOT undergo cell division
odontoblasts
makes type 1 and 3 collagens, GAGs, and most common cell type in pulp
Fibroblasts
most common immune cell in pulp
dendritic cells
acts as APC
Dendritic and Macophages
acts as a scavenger and an APC
macrophages
pro-inflammatory mediators
Macrophages
activate macophages and b cell antibody production
t-lymphocytes
present in injured pulps only
mast cells
in a 55:45 ratio in the pulp
Collagen type 1 and 3
acts as a sieve for nutrients and provides tissue tugor
GAGs/Proteoglycans
blood vessels in the pulp
arterioles, cappillaries and venules
shunting system for pulp injury and repair
arteriovenous and venovenous
helps remove tissue fluid buildup
lymphatic vessels
younger or older people pulp are more vascular?
younger-more vascular, easier to repair
coronal vascular supply is almost ______ that of radicular region
twice, because more odontoblasts and fibroblasts in those locations so need more nutrients
venules drain POSTERIORLY into
maxillary vein
venules drain ANTERIORLY into
facial vein
what vessels decrease intersititial fluid pressure
lymphatics
regulation of pulpal blood flow is controlled by
Sympathetic Autonomic System-vasoconstriction
inflammed pulp is controlled by
neuronal regulation
-A, c-fibers release neuropeptides and cause vasodilation
changes in pulp during inflammation
increase:
vascular permeability
intersitial tissue fluid/proteins
pulp is a _____-______ environment
non-compliant environment
because of it being non-compliant what occurs when theres inflammation of the pulp
strangulation of the pulp
Self Strangulation Theory
 in Tissue pressure causes strangulation of vessels, generalized collapse of all venules, cessation of blood flow and subsequent ischemia and necrosis
Does the Self stangulation theory still hold true?
No-Capillaries localize blood to specific area of injury – localization of tissue fluid pressure to injured area
DOES NOT AFFECT THE WHOLE PULP
Normal Pulpal Tissue Fluid Pressure is maintained adjacent to injured area by
1. increase intraluminal pressure of local capillaries-equal with outside pressure
2.increase exchange of nutrients/waste
3. anastomoses
4.lymphatic drainage
ALL RESULT IN LOCALIZED INFLAMMATION
what happens if the insult is removed and if it is not removed
pulp heals or becomes necrotic
maxillary teeth are innervated (sensory) by what?
V2
mandibular teeth are innervated (sensory) by what?
V3
the 2 sensory fibers of the pulp?
a-fibers (myelinated) and c-fibers (unmyleinated)
whats more abundant in the pulp, a or c fibers?
c fibers
two types of A fibers and which is more abundant
delta-more abundant
beta
nerve bundles pass through pulp and ramify into _______ in the subodontoblastic cell free zone
plexus of rashkow
fibers located in or near the odontoblast layer
a fibers
fibers within the pulp not near the odontoblast layers or cell free layers
c fibers
fastest conducting fibers and deals with pressure and touch
a beta
fibers for pain temperature and touch
a delta
pain sensation fibers
c fibers
all sensory nerve fibers in pulp/dentin function as
nociceptors
all afferent impulses generate the sensation of ____
pain
sharp/pricking pain, low threshold for exicitation
a-delta
burning aching less bearable pain, high threshold for excitation
c fibers
explain dentinal hypersensitivty
Fluid in dentinal tubules moves in response to painful stimuli
Thermal, mechanical, chemical, hyperosmotic stimuli
a-fibers act as ______receptors
mechanoreceptors activated by movement of fluid = Dentinal Pain (sharp)
causes inward flow during the Hydrodynamic Theory
heat
causes outward flow during the Hydrodynamic Theory
cold
air
hyper-osmotic
what causes a stronger nerve response, inward or outward flow
outward
pulp stone: surrounded by pulp tissue
free stones
pulp stone: continuous with dentin
attached
pulp stone: surrounded entirely by dentin
embedded
calcifications cause what type of pain symptoms and how big do they get when you feel the pain?
tricky ricky at it again. NOT RESPONSIBLE FOR PAIN SYMPTOMS REGARDLESS OF SIZE-can block access to canals during RCT
what occurs when to pulp as we grow older
Decreased cellularity
Decreased vascularity
Decreased innervation
Increased number and thickness of collagen fibers
3 types of cementum
Acellular afibrillar cementum:
Acellular extrinsic fiber cementum:
Cellular intrinsic fiber cementum:
Acellular afibrillar cementum:
Covers the teeth at and along the cemento-enamel junction (CEJ)
Acellular extrinsic fiber cementum
Confined to the coronal half of the root
Cellular intrinsic fiber cementum
is Confined to the apical half of the root
Cementum acts as an attachment for between the bone
sharpeys fibers
functions of the PDL
Supports the tooth
Absorb occlusal forces
Keep tooth in socket
connects the PDL to the tooth?
sharpeys fibers
more abundant in PULP a-delta or beta fibers?
delta
more abundant in PDL a-delta or beta fibers?
beta
a beta fibers in pdl
Allows patient identification of tooth with apical periodontitis-tap on it and can tell which tooth is tapped on
Radiopaque appearance on radiographs of alveolar bone is the
lamina dura
cause of radiographic loss of lamina dura
periapical inflammation
highest portion of the pulp-most likely for pulp exposure.
pulp horns
opening of the tooth
apical foramen
side of root to furcation area
lateral canal
bottom of pulp chamber
furcation canal
where do you stop instrumentation
at the apical constriction-minor apical diameter
Weine Classification: one single canal with one foramen
type 1
Weine Classification: two canals converging to one foramen
type 2
Weine Classification: two canals and two foramina
type 3
Weine Classification: one canal dividing into two canals with two separate foramina
type 4
Maxillary Central Incisor
Single root
Single canal most of the time
Triangular pulp chamber outline
Pulp chamber usually has 3 pulp horns (mesial, center and distal)
Average age of eruption: 7-8 yrs
Average age of calcification: 10 yrs
occurs 2-3yrs after eruption
calcifications
______ prevents direct access to the root canal and deflects files labially, often resulting in a ledge or perforation
lingual shoulder
Maxillary Lateral Incisor
Single Root
Single canal most of the time
Average age of eruption: 8-9 yrs
Average age of calcification: 11yrs
Usually has two pulp horns (mesial & distal)
Access outline similar to max. central incisor, however slightly more compressed, due to less prominent pulp horns
Maxillary Canine
Single root
Single canal most of the time
No pulp horns
Oval external access outline due to absence of pulp horns
Pulp chamber wider buccolingually than mesiodistally
Average age of eruption: 10-12 yrs
Average age of calcification: 13-15 yrs
pulp chambers
Wider BL than MD for Max Canine
Wider MD than BL for Mx Central and Lateral
Mandibular Incisors
2 canals common – 20-40% (division occurs in coronal –middle third). into one foramen-type 2 weine
pulp chamber/root canal is wider labiolingually than mesiodistally
Access outline usually oval-triangular
Average age of eruption: 6-8 yrs
Average age of calcification: 9-10 yrs
where must you open the mandibular incisors
lingually towards cingulum as the 2nd canal is often missed
Mandibular Canine
Oval access outline form consistent with pulp chamber (wide buccolingually and narrow mesiodistally)
Similar to Max canine, however dimensions are smaller and presence of 2 roots and 2 canals is not uncommon
Average age of eruption: 9-10 yrs
Average age of calcification: 13 yrs
Maxillary 1st Premolar
May have one, two, or three roots and canals; it most often has two roots with two canals
Buccal and lingual (palatal) pulp horns and a pulp chamber that is wider buccolingually than mesiodistally
Oval external access outline form
Average Age of eruption: 10-11 yrs
Average age of calcification: 12-13 yrs
because of this on Maxillary 1st premolars, if exteneded prep can cause perforation
mesial concavity
cuspal coverage Mx 1st and 2nd Premolar needed after RCT because
mesiodistal root and buccal cusps prone to fracture
Maxillary 2nd Premolar
About 50% of time 2 canals at the apex, and then converges.
Has one root most of the time ~85% single root
Root canal morphology 75 % - 1 canal at apex
Buccal and lingual (palatal) pulp horns with pulp chamber wider buccolingually than mesiodistally. Buccal pulp horn larger than lingual
Oval external access outline form BL>MD
Average Age of eruption: 10-12 yrs
Average age of calcification: 12-14 yrs
Mandibular 1st Premolar
BL>MD
Two pulp horns are present: a large, pointed buccal horn and a small, rounded lingual horn
74% one canal
2 roots – 5.5% (3 times higher incidence in African-American)
Access outline: Oval
Common to have 2 canals. And usually split. Weine type 4.
Average age of eruption: 10-12 yrs
Average age of calcification: 12-13 yrs
Mandibular 2nd Premolar
Pulp chamber and access outline - Oval
Two roots – 1.5% (3 times higher incidence in African-Americans)
Root canal morphology: 97.5% one canal
Average age of eruption: 11-12 yrs
Average age of calcification: 13-14 yrs
need to remove lingual shoulders on these teeth
Maxillary and Mandibular anteriors
Mx 1st Molar
Usually has three roots that are widely spread buccolingually
Pulp chamber widest in the buccolingual dimension, and four pulp horns are present
Pulp chamber and access outline triangular to rhomboid
Average age of eruption: 6-7 yrs
Average age of calcification: 9-10 yrs
MB root of Mx 1st Molar
70-95% 2 canals. 2nd canal is ML or MB2.
Widest buccolingually
Palatal/Lingual root of Mx 1st Molar
The palatal root is the longest, has the largest diameter, and generally offers the easiest access. From the orifiice, it is wide mesiodistally
Mx 2nd Molar
Morphology similar to 1st molar, however roots and pulp horns are closer to each other and lengths are slightly shorter
Two roots with two canals is not uncommon – 8% have only B & P canals
Lower incidence of MB2 (ML) canal relative to 1st molar
Average age of eruption: 11-13 yrs
Average age of calcification: 14-16 yrs
Pulp chamber and canals smaller MD when compared to first molar
Md 1st Molar
Earliest permanent posterior tooth to erupt and is the tooth that most often requires root canal therapy
Usually has two roots but occasionally it can have three.
3 canals – 64% (Weine Type III ~60%)-2 mesial 1 distal
Average age of eruption: 6 yrs
Average age of calcification: 9-10 yrs
Middle mesial-btw mesial buccal and mesial lingual and joins with either.
Pulp chamber floor is roughly trapezoid
Md 2nd Molar
Pulp chamber similar to 1st molar but slightly smaller and more compressed
Access outline more triangular
Presence of only 2 canals (single mesial and distal) more common than in 1st molars
Average age of eruption: 11-13 yrs
Average age of calcification: 14-15 yrs
Most frequent tooth to fracture. Bc smaller and occlusal table smaller and cant stand a lot of force. And bc of its location in the tooth
Mesial root always curves out and then in
Distal root curve straight.
third molars
Radicular anatomy of maxillary and mandibular 3rd molars are highly unpredictable and vary greatly
Root canal morphology – Anywhere from 1-4 roots with 1-6 root canals
common 3rd molar features
-Fused root system
-Short rounded crowns and conical roots
-Larger chamber area and shorter canal spaces
-Malalignment of the tooth may be a factor in treatment.
c-shaped canals are most common in
Md 2nd molar
7-8% of time and most in asians.
what is a c shaped canal
is a single, ribbon-shaped orifice with an arc of 180 degrees or more. The result is a large curved orifice.  
C-shaped-orifcaces shaped and arced in 180 degrees to apical foramen. Harder to treat and tissue in btw that’s harder to clean. A lot...
is a single, ribbon-shaped orifice with an arc of 180 degrees or more. The result is a large curved orifice.
C-shaped-orifcaces shaped and arced in 180 degrees to apical foramen. Harder to treat and tissue in btw that’s harder to clean. A lot of anastomoses and communicated with other orifices. Greater failure rate.
The floor of the pulp chamber is always located in the center of the tooth at the level of the CEJ
Law of Centrality
The walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ, that is, the external root surface anatomy reflects the internal pulp chamber anatomy
Law of Concentricity
Except for the maxillary molars, canal orifices are equidistant from a line drawn in a mesiodistal direction through the center of the pulp chamber floor
First law of Symmetry
Except for the maxillary molars, canal orifices lie on a line perpendicular to a line drawn in a mesiodistal direction across the center of the pulp chamber floor
Second Law of Symmetry
The pulp chamber floor is always darker in color than the walls
white walls, yellow pulp tissue
law of color change
The orifices of the root canals are always located at the junction of the walls and the floor
Law of orifice location:
3 uses/importance for Radiographs
diagnosis
treatment
recall
identifying pathosis
determining root and pulpal anatomy
characterizing normal structures
diagnosis
determining working lengths
locating canals
obturation
treatment
healing of the pathosis
determining other treatment options
recall
primary radiograph used in endodontics is the
Periapical Radiograph or PA.
Periapical Radiograph or PA.
-At least 2mm of bone should be visible beyond the apex of the tooth.
-Entire periapical lesion should be visible
Limitations of Radiographs
-Two dimensional representation of a three dimensional object
-Superimposition of anatomic structures
-Lesion appears in the radiograph only after certain amount of destruction of bone
How is a panoramic radiography used for diagnosis?
its not. CANT BE USED FOR DIAGNOSIS of endodontic
Buccal object rule
SLOB
Clarks Rule
Cone Shift Technique
A lingual object will move in the same M/D direction as the x-ray cone head, whereas a buccal object will move in the opposite M/D direction (Same Lingual Opposite Buccal)
A lingual object will move in the same M/D direction as the x-ray cone head, whereas a buccal object will move in the opposite M/D direction (Same Lingual Opposite Buccal)
ideal SLOB shift is
20 degrees
20 degrees
SLOB allows for:
-Location of additional canals and/or roots
-Distinction between superimposition of structure
-Determination of buccal or lingual position of anatomical features or iatrogenic mishaps
PAs distort easily so take BWs as well because:
in order to minimize elongation or foreshortening.
BW’s more accurately depict the
-depth of caries
-extent of restorations
-morphology of pulp chambers
-presence of open margins
-size, position and depth of posts
Most accurate periapical radiograph is achieved using the ________ ___________
paralleling technique
paralleling technique
The film is placed parallel to the long axis of the tooth and the central beam is directed at right angles to the film.
Most accurate representation of the tooth
The ________ ________ ________ is used during anatomic configurations (i.e., shallow palate)
bisecting angle technique
bisecting angle technique
The central beam is directed at an imaginary line that bisects the angle between the tooth and film.
Tissue destruction and Radiographs
-Tissue destruction is usually more extensive than it appears radiographically.
-12.5% of cortical plate and/or 7.4 % of mineralized bone has to be destroyed before it appears on the radiograph.
Differential Diagnosis
1. Conduct vitality tests, the presence or absence of symptoms and possible etiology.
2. Take multiple radiographs from different angles and use the SLOB rule to evaluate the situation
3. In the case of anatomical radiolucencies, the healthy tooth in question should also exhibit an intact lamina dura and PDL space.
4. Finally, knowing your anatomy will prevent a misdiagnosis!
Goldman 1974 Study
These 6 examiners agreed on less than 50% of the cases. Six to eight months later, 3 of the original examiners again viewed the same radiographs. They agreed with their own previous responses 75% to 83% of the time!
2011 Tewary Hartwell Study
digital radiographs.
Conclusion: The interpretation of radiographs is subjective and most important factors are years of experience of examiner and their familiarity with digital systems.
Tools for Diagnosis
-Chief Complaint
-History of signs and symptoms
-Clinical examination
-Radiographs (Should be ordered after the clinical examination)
The goals of endodontic treatment are to
-Prevent the development of and treat apical periodontitis
-Create adequate conditions for periradicular tissue healing
An inflammatory disease of microbial origin caused primarily by infection of the root canal system
Apical Periodontitis
two types of apical periodontitis
symptomatic and asymptomatic
prevalence
As people age and grow.-preavalence is 1/3rd but then almost doubles as you get to over 60yrs old
Etiology of apical periodontitis
Infection of the pulp tissue caused by caries or other pathways is the primary cause of apical periodontitis*
caries from coronal area into pupal space.
Other etiologies
-Physical insults(overinstrumentation, overfilling)
-Chemical insults (irrigants, intracanal medication, root canal filling materials)
-Traumatic injury to the periapical tissues
-Foreign bodies
the periapical tissue reaction to irritants emerging from the root canal system that manifests as vasodilation, increased vascular permeability and exudation
Apical inflammation
physical presence of pathogenic microorganisms in the periapical tissues that subsequently produce tissue damage
Apical infection
Routes of Root Canal Infection
-Caries, fractures, exposed dentinal tubules
-Coronal leakage
-Via periodontium
-Anachoresis
Caries, fractures, exposed dentinal tubules
Non motile-travel by reproducing themselves. And travel through dentinal tubules. Or hydrostatic prassures and fluid pushes them through tubules into the pulp. –fight with inflammation.
main bacteria
lactobacillus and step mutans
microbial ingress to the root canal system after obturation
coronal leakage
via periodontium
Microbial access to the dental tubules by periodontal disease
localization of blood-borne bacteria during bacteremia to a site of inflammation
anachoresis
degree of pathogenicity or disease producing ability of a microorganism
virulence
Characteristics of a microorganism that enable it to induce disease
virulence factors
radiographic examination
-Widening of the periodontal ligament space
-Development of apical osteolytic lesions due to bone resorption
-The loss of bone is mainly caused by activated osteoclasts.
The inflammation-induced bone resorption in the periapical tissues is accompanied by
recruitment of immune cells which essentially build a defensive line against the spread of microbial invasion from the root canal (immune response)
thick peptidoglycan
Gram +
thinner wall and outer membrane. also has LPS-pathogenic factor
Gram -
sessile multicellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self-produced matrix of extracellular polymeric substance (EPS), usually polysaccharide
biofilm
Microorganisms entering the pulp and periapical tissues must be able to :
-Colonize
-Evade host defense mechanisms
-Initiate tissue destruction
-Deal with variable conditions within the root canal system
two types of endo infections
intraradicular and extraradicular
Intraradicular Infection: Primary Infection
Caused by microorganisms that initially invade and colonize necrotic pulp tissue (initial or “virgin” infection)
Intraradicular Infection: Secondary Infection
Caused by microorganisms not present in the primary infection but introduced in the root canal at some time after professional intervention (i.e., secondary to intervention)
usually with failed RCT
Intraradicular Infection: persistent infection
Caused by microorganisms that were members of a primary or secondary infection and in some way resisted intracanal antimicrobial procedures and were able to endure periods of nutrient deprivation in treated canals
obligate anaerobes are found in the
apical area-slow growing
facultative anaerobes are found in the
coronal part of the canal-rapidly growing
most common fungal infection
candida albicans
maybe associated with irreversible pulpitis and apical periodntitis
Epstein barr virus
present in dental pulp but not required for development of acute apical abscess or cellulitis of endodontic origin
Herpes Virus
Predominantly Gram negative anaerobic rods
Primary endodontic infections
Gram positive facultative anaerobes
Previously treated canals
Detected in failed treatment 3x more than primary Tx
Enterococcus faecalis
characterized by microbial invasion of the inflamed periradicular tissues and is a sequel to the intraradicular infection
Extraradicular infection
It can be dependent on or independent of the intraradicular infection
Extraradicular infection
dependent on the intraradicular infection
take care of intraradicular infection, then extra goes away
independent of the intraradicular infection
live by itself no matter of the intraradicular infection
Independent extraradicular infections would be those that are no longer fostered by the intraradicular infection and can persist even after successful eradication
If bacteria from the infected root canal gain entry into the periradicular tissues and the immune system is unable to suppress the invasion, an otherwise healthy patient eventually shows signs and symptoms of an acute apical abscess, which can in turn evolve to cellulitis
fascial space infections