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Flashcards in Online Questions Deck (76):

What stage of tooth formation involves the beginning of invagination of the developing tooth structure?

Cap stage


What is the bell-shaped structure that develops from the tooth bud?

Enamel organ
- It is ectodermal in origin
- Will be responsible for amelogenesis.


From what are odontoblasts derived?

Neural crest cells (Ectomesenchyme)


From where is differentiation of the odontoblasts controlled?

Inner enamel epithelium
- The differentiation of odontoblasts from undifferentiated ectomesenchymal cells is initiated and controlled by the ectodermal cells of the inner dental epithelium of the enamel organ.


From where does the signal initiating enamel formation originate?

- Once dentin formation has begun, the cells of the inner dental epithelium begin to respond to a signal from the odontoblasts and begin to deposit enamel.


When does the dental papilla become the dental pulp?

Late bell stage
- Odontoblasts begin to lay down dentin in the late bell stage. From this point on, the tissue within the invagination is known as the dental pulp.


What is the first thin layer of dentin that is formed?

Mantle dentin
- The first thin layer of dentin formed is called mantle dentin. The direction and size of the collagen fibers in mantle dentin differ from those in the subsequently formed circumpulpal dentin.


Epithelial cell rests of Malassez are remnants of what?

The Epithelial Rooth Sheath
- Epithelial cell rests of Malassez are cell remnants of the epithelial root sheath that persist in the periodontium in close proximity to the root after root development has been completed. They are normally functionless, but in the presence of inflammation, they can proliferate and under certain conditions may give rise to a radicular cyst.


Which cells secrete the hyaline layer of Hopewell-Smith?

Inner cells of Hertwig’s epithelial root sheath
- After the first dentin in the root has formed, the basement membrane beneath Hertwig’s sheath breaks up, and the innermost root sheath cells secrete a hyaline material over the newly formed dentin. After mineralization has occurred, this becomes the hyaline layer of Hopewell-Smith, which helps bind the soon to be formed cementum to dentin


What morphologic changes occur over time due to the dental pulp?

The overall size of the pulp chamber is reduced


The apical foramen is:

Variable in size and location


The apical constriction is:

The ideal end point of root canal cleansing


What does the dental pulp form as a defensive response?

Tertiary dentin


Approximately how many odontoblasts are present in the crown of a newly erupted tooth?

45,000 to 65,000/mm^2
- In the coronal part of the pulp space, the odontoblasts are numerous, relatively large, and columnar in shape


Which of the following cell types is an antigen-recognition cell in the dental pulp?

- Toll-like receptors (TLR2 and TLR4), when activated by components of gram-positive bacteria (lipoteichoic acid), cause the odontoblasts to release proinflammatory cytokines


What is the most prominent antigen-presenting cell in the dental pulp?

Dendritic cell
- These are antigen-presenting cells present most densely in the odontoblast layer and around blood vessels.


What type of collagen is most prominent in the dental pulp?

Type I


Which of the following is not a type of pulp stone?
- free
- attached
- embedded
- floating



What would be a typical level for interstitial pressure in a dental pulp?

+6 mmHg


What would be a typical level for interstitial pressure in an area of inflammation in a dental pulp?

+20 mmHg


Which type of nerves can be recruited to the pain system of the dental pulp in inflammation?

- Their role in the pulp is uncertain, but it is now known from other tissues that in inflammation, these Aβ fibers can be recruited to the pain system.


What is a “pulp cap”?

Capping of exposed vital pulp tissue by placing a layer of mineral trioxide aggregate (MTA)


What is the effect on blood flow to the pulp when anesthetics with vasoconstrictors are used during restorative procedures?

It is reduced to less than half of its normal rate
- When most local anesthetics containing vasoconstrictors are used in restorative dentistry, the blood flow to the pulp is reduced to less than half of its normal rate. In the case of lidocaine with epinephrine, this effect is entirely due to the vasoconstrictor.


What is dentin “blushing”?

Vascular injury (hemorrhage) of pulp tissue, often during crown preparation
- Thought to be due to frictional heat resulting in vascular injury (hemorrhage) in the pulp.


Why are deeper carious lesions more injurious to the dental pulp?

Increased dentin permeability in deeper areas and greater cellular injury to odontoblasts
- Dentin permeability increases exponentially with increasing cavity depth, as both the diameter and density of dentinal tubules increase with cavity depth (Fig. 2.5). Thus the deeper the cavity, the greater the tubular surface area into which potentially toxic substances can penetrate and diffuse to the pulp.


Why does a blast of compressed air directed at freshly exposed dentin create a sensation of pain?

It causes a rapid outward movement of fluid in patent dentinal tubules


What is the most important characteristic of any restorative material in determining its effect on the pulp tissue?

Ability to form a marginal seal
- That prevents the leakage of bacteria and their products onto dentin and then into the pulp.


What effect does orthodontic tooth movement have on the dental pulp?

It produces no clinically significant changes


What is the primary reason for placement of a liner between biocompatible restorative materials and the dentin?

To eliminate microleakage


Vital pulp therapies have variable rates of success. What is the most significant determinant of the success of vital pulp therapy?

Pulp status before the procedure


Which of the following steps is used in step-wise evacuation of caries?
- Removal all the caries in a single visit
- Placement of a calcium hydroxide base at the initial visit
- Placement of a glass ionomer base at each visit
- Removal of only a superficial layer of caries at the first visit

Placement of a glass ionomer base at each visit


What factors should be considered in case selection for direct pulp capping procedures?

Asymptomatic teeth with vital pulp


When does apical closure occur in the developing root?

Approximately 2 to 3 years after eruption


If the pulp becomes necrotic before root growth is complete, the resultant root is:

Short with thin dentin walls
- Dentin formation ceases and root development is arrested


What is apexogenesis?

Continued physiologic root formation


What is apexification?

Induction of a calcific barrier across an open apex


What is the ultimate goal of endodontic treatment?

To prevent or treat apical periodontitis


Why is there greater dentin permeability near the pulp?

Higher density of dentinal tubules


Bacterial invasion of dentinal tubules occurs more rapidly in which teeth?

Nonvital teeth


What is anachoresis?

Microorganism transport from blood vessels into damaged tissue


Root canals can become infected through anachoresis.

- There is no clear evidence showing that this process can represent a route for root canal infection. It has been shown that bacteria could not be recovered from unfilled root canals, when the blood stream was experimentally infected, unless the root canals were overinstrumented during the period of bacteremia, with resulting injury to periodontal blood vessels and blood seepage into the canal.


Which of the following is not a category of intraradicular infections?
- Primary
- Secondary
- Tertiary
- Persistent

- Intraradicular infections can be subdivided into three categories (primary, secondary, or persistent infection), depending upon when participating microorganisms established themselves within the root canal.


The most common microorganisms in primary endodontic infections are:

Gram-negative bacteria


Which is not a source of nutrients for bacteria within the root canal system?

Inflamed vital pulp tissue
- In the root canal system, bacteria can use the following as sources of nutrients: (1) necrotic pulp tissue, (2) proteins and glycoproteins from tissue fluids and exudate that seep into the root canal system via apical and lateral foramina, (3) components of saliva that may coronally penetrate the root canal, and (4) products of the metabolism of other bacteria.


Which microorganism is 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:
- Have a higher occurrence in post-instrumentation samples
- Be more resistant to antimicrobial treatments
- Adapt to harsh environmental conditions
- All of the above

All of the above
- Have a higher occurrence in post-instrumentation samples
- Be more resistant to antimicrobial treatments
- Adapt to harsh environmental conditions
Gram-positive bacteria can be more resistant to antimicrobial treatment measures and have the ability to adapt to the harsh environmental conditions in instrumented and medicated canals.


A direct pulp exposure of a carious lesion is necessary to have a pulpal response and inflammation.



What factor is the most important in determining whether pulp tissue becomes necrotic slowly or rapidly after carious pulp exposure and pulpal inflammation?

Lymph drainage
(1) Virulence of the bacteria
(2) Ability to release inflammatory fluids to avoid a marked increase in intrapulpal pressure
(3) Host resistance
(4) Amount of circulation
These are ALL factors but the MOST IMPORTANT is
(5) lymph drainage.


What is necessary for pulp and periradicular pathosis to develop?

Presence of bacteria

-Pulpal or periradicular pathosis does not develop without the presence of bacterial contamination


Which of the 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?



What cell type associated with immune response is not present in severely inflamed dental pulp?



What is the cause of pain during the progression of pulpal injury?

Increase of venule vascular permeability

Pain is often caused by several factors. The release of mediators of inflammation causes pain directly by lowering the sensory nerve threshold. These substances also cause pain indirectly by increasing both vasodilation in arterioles and vascular permeability in venules, resulting in edema and elevation of tissue pressure. This pressure acts directly on sensory nerve receptors.


Which of the following is true in reversible pulpitis?

Yields a positive response to thermal pulp testing


What is irreversible pulpitis?

A severe inflammatory process

Irreversible pulpitis may be classified as symptomatic or asymptomatic. It is a clinical condition associated with subjective and objective findings indicating the presence of severe inflammation in the pulp tissue. Irreversible pulpitis is often a sequel to and a progression of reversible pulpitis. Severe pulpal damage from extensive dentin removal during operative procedures or impairment of pulpal blood flow as a result of trauma or orthodontic movement of teeth may also cause irreversible pulpitis. Irreversible pulpitis is a severe inflammatory process that will not resolve even if the cause is removed.


Which of the following is not a hard tissue change that may result from pulpal irritation or inflammation?

Thickening of the periodontal ligament


What are the signs and symptoms associated with symptomatic apical periodontitis (SAP)?

Marked or excruciating pain on tapping with a mirror handle


What histologic feature differentiates a periapical granuloma from a periapical cyst?

Presence of an epithelium-lined cavity


Which of the following is not associated with acute apical abscess (AAA)?

An intense and prolonged response to thermal stimulus

AAA is characterized by a rapid onset and spontaneous pain. Depending on the


What factors may impact and influence whether periradicular lesions heal completely or incompletely?

Size of the lesion
Blood supply
Systemic disease
All of the above

All of the above

Size of the lesion
Blood supply
Systemic disease


What is the most important aid in distinguishing between endodontic and nonendodontic periradicular lesions?

Pulp vitality testing


Localization of pulpal pain is more difficult than localization of periradicular pain



What is the distinguishing characteristic of a chronic apical abscess (CAA)?

The presence of an abscess that is draining to a mucosal or skin surface

CAA is an inflammatory lesion of pulpal origin that is characterized by the presence of a long-standing lesion that has resulted in an abscess that is draining to a mucosal (sinus tract) or skin surface.


Which of the following are changes that occur in the pulp with age?
(1) decreased vascular elements
(2) decreased amount of collagen
(3) increased number of fibroblasts
(4) decreased number of odontoblasts
(5) increase in occurrence of calcifications

1, 2, and 3
1, 3, and 5
1, 4, and 5
2, 3, and 5
all of the above

1, 4, and 5

There is a decrease in cells, including both odontoblasts and fibroblasts. There are also fewer supportive elements (i.e., blood vessels and nerves). Fewer and smaller vessels result in a decrease in blood flow in the pulp; the significance of this decrease is unknown. Capillaries show somewhat degenerative changes in the endothelium with age. There is presumably an increase in the percentage of space occupied by collagen but less ground substance.


Which statement is not true regarding calcifications in the pulp space?

Pulp stones can increase the incidence of odontogenic pain.

Calcifications include denticles (pulp stones) and those that are diffuse (linear). These increase both in the aged pulp and in the irritated pulp. Pulp stones tend to be found in the coronal pulp, and diffuse calcifications are found in the radicular pulp.


Which of the following occurs in the pulp chamber in molars with age?

Decreases primarily in an occlusal-apical dimension


The healing capacity of older patients is significantly less than that of younger patients because of a decrease in periapical vascularity. The vascularity of the periapical tissues is a critical determinant in healing.

T/F, F,T, T/T, F/F?

The first statement is false; the second statement is true.

No evidence exists that vascular or connective tissue changes in older individuals result in significantly slower or impaired healing. Overall, there is little difference in the nature of healing between the age groups, including healing of both bone and soft tissue. Vascularity is critical to healing, and in healthy individuals, periapical blood flow is not impaired with age.


Which medical condition may directly affect (decrease) pulp resistance to injury?

None of the above

None of the above

There is no conclusive evidence that systemic or medical conditions directly affect (decrease) pulp resistance to injury.


How does pulp testing differ between older and younger patients?

Testing should be done slowly and carefully in older patients.

The pulp becomes less responsive to stimuli with age, particularly with calcific metamorphosis. Thus testing in older patients should be done slowly and carefully, with the use of different stimuli. It is common for a tooth with a vital pulp to be nonresponsive to one form of testing (e.g., cold) but to respond to another stimulus (e.g., electrical stimulus).


Which of the following is a common finding on examination of geriatric patients?

Extensive restorative experience with multiple large restorations and crowns


Which of the following is a difference between geriatric and younger patients that may affect the ability to reach a diagnosis?

Older patients are more stoic.
A decreased response to pulp testing is common.
Symptoms of pulpitis are not as acute in older patients.
All of the above

All of the above

Older patients are more stoic.
A decreased response to pulp testing is common.
Symptoms of pulpitis are not as acute in older patients.


What is a common radiographic factor in older patients?

The incidence of nonendodontic pathosis of the jaws tends to increase with age.

Bony growths, such as tori and muscle attachments (frena), may affect film positioning. Also, the older patient may have difficulty placing the film; therefore, holders should be used.


A common modification in performing root canal treatment for older patients is which of the following?

Beginning an access cavity without a rubber dam to locate a smaller chamber

A very small or nonvisible chamber may be an indication for beginning the access without the rubber dam; this aids in staying in the long axis of the tooth (Fig. 25.12). Once the canal has been located, the rubber dam is immediately placed, before working length radiographs are made.


Working length determination in elderly patients may be more difficult because of which of the following?

Increased apical foramen variability, modifying the apical anatomy

There are some differences in working length in the older patient. Because the apical foramen varies more widely than in the younger tooth and because of the decreased diameter of the canal apically, it is more difficult to determine the preferred length


Which statement is true about factors that may reduce the rate of success and healing of periapical tissues in older patients?

Canals may not be negotiated to length and may contain persistent irritants.


Which of the following is common in older patients after endodontic surgery?

Older patients experience more ecchymosis after surgery.