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In Classification, diagnosis and clinical manifestations of apical periodontitis PAUL V. ABBOTT 2004 Endodontic topics

how long did it take bacterial infection to render the canals void of pulp in teeth with closed and open apices?

2months - open apex

 1month - closed apex


In Classification, diagnosis and clinical manifestations of apical periodontitis PAUL V. ABBOTT what did Abbott quote Sundqvist as having found?

Sundqvist (19) confirmed that periapical lesions were found in 18 of 19 cases where microbes were present in the canal and the size of the periapical radiolucency was directly related to the number of strains that could be isolated from the affected tooth.


When can periodontal disease  without endodontic disease mimic apical periodontitis ?

Periapical radiographs may falsely suggest an area of apical periodontitis without infection of the root canalsystem when there is extensive periodontal disease andthe pocket has extended beyond the level of the rootapex

In this situation, substantial breakdown of the supporting tissues and loss of bone (either labially orlingually) creates a radiolucency, which is superimposed over the periapical region giving the appearance of apical periodontitis


In Classification, diagnosis andclinical manifestations of apical periodontitis PAUL V. ABBOTT 2004 Endodontic topics

 what does Abbott propose as a classification system?

Table2. A clinical classification of the status of the periradicular tissues.

(a)Clinically normal periapical/periradicular tissues

(b)Apical periodontitis-Acute:Primary Secondary (or acute exacerbation)-Chronic: Granuloma Condensing osteitis

(c)Periapical cyst-True cyst, Pocket cyst

(d)Periapical abscess-Acute: Primary, Secondary- Chronic

(e)Facial cellulitis

(f)Extra-radicular infection

(g)Foreign body reaction

(h)Periapical scar

(i)External root resorption-Surface-Inflammatory-Replacement-Invasive-Pressure-Orthodontic-Physiological


 In Classification, diagnosis andclinical manifestations of apical periodontitis PAUL V. ABBOTT 2004 Endodontic topics what does abbott quote as Nair's 1997 finding regarding the presence of epithelium in apical periodontitis versus in true cysts?

Nair found over  50% of apical periodontitis lesions had epithelium present on histopathological sectioning  and subsequently the mere presence of epithelium was insufficient to make a diagnosis of a cyst.

Nair proposed that peripaical lesions must be examined in order to determine whether the epithelium forms a complete capsule around the periphery of the lesion and whether there is any communication with the root canal system


What defines a periapical pocket cyst?

A sac-like epithelium-lined cavity that is open to, and continuous with, the root canal


What defines a true periapical cyst?

A true cyst is completely enclosed by the epithelial lining and there is no communication with the root canal

 This is important as if the cyst exists separate to the root canal system then endodontic therpy will not resolve the lesion it will need to be treated separately.


Define a normal periodonteum

The tooth is not tender to percussion or pressure, and there is no tenderness to palpation of the mucosa overlying the periapical region. There is no swelling and there are no symptoms noted by the patient. Radiographically, the lamina dura is intact and the perio-dontal ligament space has a normal and consistent width around the entire root(s) of the tooth. The width of the periodontal ligament space should also be similar to that of the adjacent teeth


Other than radiolucency how might chronic apical periodontitis present?

 How is this distinguished radiographically?

As condensing osteitis or idiopathic bone sclerosis.

This can be easily distinguished from other chronic periapical conditions by its radiographic appearance since the periapical bone will appear more radiopaque than normal bone. Some cases may also have a slightly widened periodontal ligament space between the tooth root and the radiopacity.


In Classification, diagnosis and clinical manifestations of apical periodontitis PAUL V. ABBOTT 2004 Endodontic topics

 what is the recommendation for obturation material extruded beyond the apex of the tooth into the periapical region where there is concern of a foreign body reaction causing apical periodontitis

If there is a radiolucency present in conjunction with extruded root filling material, then healing cannot normally be attained by orthograde endodontic re-treatment. If this lesion has been caused by a foreign body reaction- meaning the obturation material extruded into the periapical region. Ideally in such a case, the periapical region should be monitored radiographically for several years to determine whether it heals before surgery is even considered


In Classification, diagnosis and clinical manifestations of apical periodontitis PAUL V. ABBOTT 2004 Endodontic topics

What 4 factors should be considered for every endodontic examination?

1. the status of the pulp

2. the status of the root canal

3. the status of the periapical tissues

4. the causes(s) of the condition(s).


What is the recommended limitation to scaling time/tooth for ultrasonic scalers?

Verez- fraguela's study JVD 2000 recommended that an ultrasonic scaler be used for no longer than 30 seconds per tooth.

 pulp necrosis thought to be the result of the resonance effect on the pulp resulted from 30 seconds of continuous use of the US scaler without water cooling . Acute pulpitis was evident after 15 days when this occurred


What is depicted here and how has it occurred ?

 What treatment should be applied?

Hyperplastic pulpitis 

 The pulp has attempted to respond to a complicated crown fracture and as a result the resulting granulation tissue has occluded and overgrown the fracture site.

 the pulp is generally in the terminal stage of change from vital to non vital- root canal therapy is indicated.


What is required to make a definitive diagnosis of apical periodontitis



What are the five groups of apical periodontitis as categorized by WHO?

1. acute apical periodontitis of pulpal origin

2. chronic apical periodontitis 

 3. periapical abcess with sinus

4. periapical abcess without sinus

5. radicular cyst


 When should teeth with root frctures be removed?

When the coronal segment is unstable and cannot be stabilised causing periodontal disease to ensue.

strangulation of the pulp may occur and may warrant RCT


According to Wiggs's what are the different types of endodontic /periodntic lesions?

 primary endodontic

 primary periodontal

 primary periodontal secondary endodontic

 primary endodontic  with secondary periodontic

combined endodontic periodontic  lesions

concomitant endodotnic and periodontic



What is a j lesion in endodontics?

A primary endodontic lesion which extends around the apex of the tooth into  wide periodontal dpace and then up to the gingival margin


How does a primary endo-secondary perio lesion differ from the reverse?

primary periodntal lesions will have a wedge shaped  loss of alveolar bone  and widening of the periodontal ligament space at the coronal edge.


What diagnostic tests can be used  to make an endodontic assessment of a tooth which are complimentary to visual examination




tactile assessment


What causes ledging, gouging, zipping, stripping and translation.

 All of these  are created by the use of a straight stiff file working in a curved canal and trying to regain its  stright shjape within the canal during instrumentation.


What is a barbed broach used for?

Removing the pulp from a canal, or removing medicaments, treatment materials and debris


How is a barbed broach applied to a pulp canal?

 it is inserted, turned 180degrees  and then retracted.


How is a barbed broach made?

It is made by  making small incisons in the shaft of a smooth broach. the incisions are forced open making small barbs which represent weak points in the broach.


 How is the size of the barbed broach selected?

It should be slightly smaller than the width of the  pulp canal so as to not engage in the  dentinal walls of the canal.


How is a k file made?

Manufactured from a straight stainless steel rod machined into a three or four sided tapered pyramidal blank. In cross section this would be an equilateral triangle, square or rhomboid.

 The terminal end is then twisted to produce the spirals on the working end of the file.


What is the difference between a reamer and a  file?

 A reamer has less cutting flutes per millimeter of operating head. reamers also have. smaller helical angle when compared with a file

Reamers are used in a clockwise turn fashion and a file is used as a quarter turn  and pull mode

 A  reamer  has 0.28-0.80 cutting flutes/mm

A file has 0.88-1.97 cutting flutes/mm



How are H files made?


What features of an H file make it weaker than a K file?

 The H file is only as strong as the central core

If the H file is used in a turn and pull fashion the large helical angle  will lock into the dentin.



How does a standard  file size taper from the tip to teh end of the operating head

 A size 15 file will be 0.15mm  1mm from the tip of the file. It will then taper 0.02mm for every mm of length for the 16mm of operating length and this will be 0.47mm at the end of the operating head.

 They are colour coded

White Yellow Red Blue Green Black



 What is the difference in the mechanics of debridement using an h file compared with a K file?

The K- file  is used in a rotate and pull or reaming motion and the H  file is used ina rasping motion.

 the h file is generally used to achieve coronal flare and the k file is used to achieve a rounded conical apical preparation


Condensers are  also known as pluggers.  What shape are they?

They have a flat end and are round in cross section with a slight taper, They are used for compacting material vertically into the apical portion of the tooth.


Spreaders are shaped differently to a plugger . In what way and what are they used for?

Spreaders also have a round cross section and are tapered,but they have a  pointy tip and are used for  lateral compaction of obturation material within the canal.


What is a lentulo and what does it do?

Lentulos are also called a spiral paste filler and they are used on a slow speed handpiece in a clockwise direction to spin sealer or paste into a pulp canal.


 Gates Glidden burs and  peeso reamers  are used for what purpose and what risk do they represent?

They are used to open the coronal portion of a canal or the straight  portion of the canal. They should not be used in a curved canal as the delicate shaft can easily break under flexion in a curved canal.


What is gutta percha and  and where does it come from?

It is a natural rigid latex from the Palaquim tree Palaquin gutta.


What are the two forms of gutta percha? how is it changed from one phase to another?

Gutta percha cones are manufactured in a rigid crystalline beta form.

 They can be changed to  the alpha form by heating the, which is sticky, pliable and flowable under pressure and then to an amorphous form which is plastic and can be molded. If cooling is very slow the alpha phase can be maintained.


What are the constituents of  a guuta percha point?

18-22% gutta percha and 59-76% zinc oxide and the remainder is a combination of radiodense materiald and plasticizers.


What are the  sizes of gutta oercha cones and what specific part of pbturation are they used for?

 There are standard points which match the sizes of the endodontic files and are used as primary cones and conventional points which  match the  taper of an endodontic spreader and are used predominantly as accessory cones.


What are the functions of  irrigant solutions in the root canal process?

They act as a lubricant, 

They dissolve organic pulp and necrotic debris

They soften dentin

They destroy bacteria

They flush debris from the canal

They remove the smear layer


How is the smear layer formed?


 the smear layer is formed during instrumentation and is caused by mechanical instruments  or files cutting the dentin and wiping fine particles , organic debris  and bacteria on the canal wall and forcing  it into the open dentinal tubules.


What are the ideal properties of an irrigant?

dissolve organic material

dissolve inorganic material




 able to penetrate dentinal tubules

 Easy to use


What are the commonly used irrigants? what are their individual features?

NaOCl  - sodium hypochlorite is used at 3 or 6% the full strength percentage has good tissue hydrolysing and antimicrobial properties whilst dirupting biofilms 

EDTA - ethylenediaminetetraacetic acid  is used at 17% as a chelating agent  to decalcify dentin and remove the smear layer

 Chlorhexidine is used at 2%  and has antimicrobial properties but will not remove the biofilm or dissolve necrotic organic material

Hydrogen peroxide is an effective antibacterial irrigant removing debris by effervescing but has no effect on necrotic organic material

Sterile saline is effective in diluting the pollution but has no effect on the smear layer the biofilm or in dissolving the organic tissue.



What should be avoided when making an access hole?

Avoid making access holes over