JOVD 2014#1 Assessment of Apical Periodontitis in Dogs and Humans: A review

Question 1

Authors?

Answer 1

Menzies, Reiter, Lewis

Question 2

What are the 5 major categories of apical periodontitis in humans that the WHO recognizes?

Answer 2

1 acute apical periodontitis of pulpal origin 2 chronic apical periodontitis 3 periapical abscess with sinus 4 periapical abscess without sinus 5 radicular cyst

Question 3

According to this review article do radicular cysts recognized to occur in dogs?

Answer 3

No

An erratum was published on this article

On page 8, paragraph 2 it is incorrectly stated that radicular cysts are not recognized to occur in dogs. The reference provided was published prior to the publication of two confirmed cases of radicular cysts. Two suspected cases of radicular cysts have also been published. Radicular cysts and periapical cysts are synonyms; periapical cysts in dogs were briefly elaborated on in the last paragraph of page 9.KH

Question 4

What is common is condensing osteitis and does is occur in humans and dogs?

Answer 4

An uncommon manifestation of periapical inflammation in humans and dogs. This occurs in a host with unusually strong local tissue resistance and a low-grade chronic pulpitis. The residual infection persists following root canal therapy however a net increase in bone production rather than destruction is seen.

Question 5

What is the primary etiology of apical periodontitis?

Answer 5

An infection of the root canal and its contents

Question 6

What are the most common routes of entry for infection ? (In descending order of frequency)

Answer 6

1 breaches in the dental hard tissue 2 severed periodontal blood vessels 3 anachoresis 4 mechanical debridement and chemical sterilization process during root canal therapy

Question 7

What is the most common cause of persistent asymptomatic periapical disease following endodontic treatment in humans?

Answer 7

Continued intraradicular microbial presence within the complex apical root canal system

Question 8

What are 5 causes of persistent intraradicular infection following standard RCT?

Answer 8

1 inadequate aseptic control 2 poor access cavity design 3 missed apical and non-apical ramifications 4 inadequate instrumentation and debridement 5 marginal temporary or permanent restoration leakage

Question 9

What are the 4 stages of apical periodontitis?

Answer 9

1 pulp exposure and colonization by microbes 2 inflammatory response 3 necrosis of the pulp 4 extension of inflammatory response extending to the periapical tissue

I would rather put:

1. pulp exposure and colonization by microbes
2. inflammatory response which lead to necrosis of the pulp
3. extension of inflammatory response extending to the periapical tissue
4. Uncoupled periapical bone resorption and a granuloma (and possibly a cyst) formation

Root canal acts as a reservoir of infection, which is inaccessible to the host’s immune system. Healing may only occur if the endodontic infection is controlled

Question 10

In infected teeth what is the microbial profile in intact teeth? In teeth with pulp exposure?

Answer 10

Intact teeth= 90% of bacteria are obligate anaerobes

Pulp exposed teeth= 70%

Question 11

How quickly following infection is the “consequences” of immune response seen histologically? Radiographically?

Answer 11

7 days=histo

14 days=radiograph

Question 12

What is a pocket cyst?

Answer 12

Form as an apithelial cell-lined sack-like extension of the root canal cavity.

Question 13

What is a true cyst?

Answer 13

Thought to originate from proliferation of the cell rests of Malassez; not in continuation with root canal

Question 14

What are the 4 zones of bone infection?

Answer 14

1. zone of stimulation
2. zone of irritation
3. zone of contamination
4. zone of infection

Question 15

In condensing osteitis which zone is the only one to involve the periapical tissue?

Answer 15

Zone of stimulation ( increased osteoblastic activity and overall lack of osteoclastic cells seen on a cellular level)

Question 16

What is the principal differential diagnosis to condensing osteitis?

Answer 16

Idiopathic osteosclerosis–both are asymptomatic, are more commonly seen in the mandible and are usually an incidental finding on dental radiographs The radiographic distinction between the two is made by assessment of the endodontic health of the associated tooth

According to AVDC Nomenclature:

Osteosclerosis (OSS): Excessive bone mineralization around the apex of a vital tooth caused by low-grade pulp irritation (asymptomatic; not requiring endodontic therapy)

Condensing osteitis (COO): Excessive bone mineralization around the apex of a non-vital tooth caused by long-standing and low-toxic exudation from an infected pulp (requiring endodontic therapy)

Question 17

What is the Hayflick limit?

Answer 17

The limited life span and capability for division of somatic cells

Question 18

Replacement of damaged cementoblast occurs where?

Answer 18

Within the periodontal ligament

Question 19

When no radiographic abnormalities were detected histological analysis confirmed apical periodontitis in what % of cases? And what % when it was detected on radiographs?

Answer 19

40% and 90%

Question 20

What are the 5 patterns of condensing osteitis?

Answer 20

1. target
2. focal
3. lucent
4. multiconfluent
5. resorptive

Question 21

Which pattern of condensing osteitis is the most common in vet. dentistry?

Answer 21

target–a radiolucent border surrounding a radiopacity

Question 22

What are the radiographic variable that could limit detection of apical periodontitis?

Answer 22

1. extent of the lesion
2. location of the lesion
3. location of the root apex
4. surrounding anatomy and anatomical features
5. angle of the x-ray
6. x-ray exposure technique
7. film processing technique
8. view interpretation

Question 23

True or False: You can differentiate between cyst, granuloma, abscess and fibro-osseous lesions using radiography

Answer 23

No, all of these lesions require histological diagnosis

Question 24

What is the minimum amount of mineralized bone loss required in order for focal bone resorption to be detected radiographically in human?

Answer 24

7.1%

Question 25

How much demineralization is required to detect generalized osteoporosis in human?

Answer 25

30-50%

Question 26

What is the primary endogenous absorber of x-rays?

Answer 26

Calcium hydroxyapatite

Question 27

True or False: A lesion will appear radiographically if it is very large even if it only involves cancellous bone?

Answer 27

FALSE–the proportion of total mineralized bone lost is likely to be too small to be distinguished on a radiograph.

Question 28

True or False: A very small lesion involving cortical bone will show significant changes that are discernable on radiographs?

Answer 28

TRUE

CP: but still since depiction of a resorptive bone lesion depends on a percentage change in total tissue density, areas of lower total density will correspondingly require a smaller volume of cortical bone resorption to be detected,so thicker cortical bone will need larger lesion than cortical bone (lost must be > 7% of total bone density)

Question 29

True or False: How soon a periapical lesion is detected on a radiograph usually depends on the proximity of the root apex to the cortex

Answer 29

TRUE

Question 30

True or False: Lesions are detectable once they involve the lamina dura

Answer 30

FALSE: most detectable lesions require both the loss of the lamina dura and the surrounding trabecular bone

Question 31

What are 2 reasons that there may be a transient increase in periapical radiolucency following root canal therapy?

Answer 31

• chemomechanical irritation
• protracted healing phase

Question 32

Which imaging mode has been shown to be more reliable at diagnosing apical periodontitis in dogs–CBCT or standard intraoral radiographs?

Answer 32

CBCT

Question 33

What is the sensitivity and specificity of periapical radigraphy compare to CBCT in diagnostic of apical periodontitis?

Answer 33

Radiog: Sens: 0.77; Spec: 1; PPV:1; NPV: 0.25; so 75% of negative result, dx healthy, had apical periodontitis; ACC: 78%

CBCT: Sens: 0.91; Spec: 1; PPV1; NPV: 0.46; so 54% of negative result, dx healthy, had apical periodontitis; ACC: 92%

Question 34

What are 3 advantages of CBCT over standard intraoral radiographs in regards to apical periodontitis?

Answer 34

1. CBCT was able to detect apical periodontitis in dogs as early as 7 days compared to radiographs at 15 days
2. CBCT allows for 3D interpretation
3. CBCT does not require cortical bone involvement for detection of the lesion

Question 35

Why did the image not appear on A and C but didn appear on B?

Answer 35

A: The amount of demineralized bone was less than 7.1% and therefore did not appear radiographically

B. The lesion appeared to involve a part of the mandible with thinner cortices (therefore more than 7.1%) and hence appeared

C.) The lesion only involved cancellous bone (no cortices) and therefore did not appear.

Question 36

To which teeth correspond the CBCT images and what does the arrow point to?

Answer 36

• Mesial root of left 2nd Mn premolar, left Mn canine root
• Arrow: Left middle mental foramen