Resorption 1 - Intro + Internal - 2020

Question 1

What is required for root resorption?

Answer 1

Continual stimulation

Breakdown of the natural barriers (cannot control but can be prevented)

A blood supply

Question 2

What factors should be considered when managing patients with resoption?

Answer 2

Can’t control the breakdown of natural barriers if the resorption has started but the continual stimulation can be removed and the blood supply can be reduced.

Question 3

What are the types of resorption?

Answer 3

Internal and external.

Internal can be surface, inflammatory or replacement

External can be surface, inflammatory, replacement, invasive, orthodontic, pressure, physiological, or idiopathic.

Question 4

What is internal root resorption?

Answer 4

Internal resorption caused by removal of dentin by clastic cells. It begins at the root canal wall and progresses through dentin towards the cementum.

May also resorb cementum and perforate the external root surface

Question 5

How common is internal root resorption?

Answer 5

Not very common and affects 1 in 1000 teeth.

Typically 1 tooth per patient

Very occasionally 2 adjacent teeth with trauma the likely factor

Question 6

Which teeth commonly are affected by internal root resorption?

Answer 6

2% of luxated teeth

Cabrini et al showed that 28% occur following pulpotomy

Ahlberg et al showed that 55% occur after autotransplantation

Question 7

What is internal resorption often confused with?

Answer 7

External invasive root resorption

Question 8

What is the most common type of internal root resorption?

Answer 8

Internal inflammatory resorption

Question 9

What are the less common types of internal root resorption?

Answer 9

Internal surface resorption is very rare and cannot be detected clinically or radiographically

Internal replacement resorption is also very rare and is not well known or understood. Can easily be confused with external invasive resorption

Question 10

What are the features of internal SURFACE resorption?

Answer 10

Minor areas of resorption of the root canal wall

Not visible radiographically

Only noted histologically

Believed to be self limiting if the irritant is removed

May be a precursor to internal inflammatory resorption?

Question 11

What are the possible causes of internal SURFACE resorption?

Answer 11

Trauma to the tooth

Necrosis + infection of the coronal pulp

External whitening/bleaching of the tooth

Aetiology is UNKNOWN in most cases.

Question 12

What did the Seale et al study show about internal root resorption?

Answer 12

Dog teeth treated with 35% hydrogen peroxide applied once per week for 4 week experienced internal surface resorption and active dentinoclasts were seen.

Question 13

What is the pathogenesis of internal root resorption?

Answer 13

Largely unknown

Needs a stimulus (as discussed)

Transient in nature

Question 14

How is internal surface resorption diagnosed?

Answer 14

Can not diagnose clinically

Can not be diagnosed radiographically but progression to inflammatory can be monitored radiographically

Question 15

How is internal surface resorption managed?

Answer 15

If resorption continues as seen radiographically it is like internal inflammatory resorption

Therefore do root canal treatment

Question 16

What are the features of internal inflammatory resorption?

Answer 16

Usually described as a radiolucent “oval-shaped” increase of pulp space (not necessarily always oval shaped though)

It can occur anywhere along the length of the canal

Question 17

What are the possible causes of internal inflammatory resorption?

Answer 17

Trauma to the tooth

Necrosis + infection of the coronal pulp

Caries + Perio disease.

Aetiology is not always known or obvious

Question 18

What is the pathogenesis of internal inflammatory resorption?

Answer 18

Bacteria in the pulp -> Damage to odontoblast layer and predentine of the canal wall must be damaged -> Exposure of mineralised dentine to clastic cells

Anything that irritates the pulp can cause this to happen

Question 19

How does the causative agent of internal root resorption affect the type of root resorption observed?

Answer 19

If the cause of pulpitis was not bacteria, the number of macrophage-like cells declined after 6 - 10 weeks and fibroblast-like cells and hard tissue started forming.

If the cause was bacteria more extensive resorption was observed

Question 20

What are the histological features of teeth that have undergone internal inflammatory root resorption?

Answer 20

Bacteria detected in the dentinal tubules and the pulp space coronal to the resorptive defect where the pulp was necrotic

The clastic cells had strong tartrate resistant acid phosphatase activity and lack of odontoblasts.

Normal pulp tissue was not present (no odontoblasts and no predentin were present and instead the pulp was replaced by periodontal-like connective tissue)

Apical third of the canal had inflamed pulp.

Question 21

What is the overall pathogenesis of internal inflammatory resorption?

Answer 21

Coronal to the resorptive defect = necrotic and infected pulp tissue

Within the resorptive defect = Grnaulation tissue with clastic cells

Apical to the resorption area = pulp will be irreversibly inflamed or replaced with periodontal like connective tissue unless resorption no longer active

Progression due to interaction between the bacteria
and the tissue remaining apically - until it necroses
 The “bacterial front” gradually moves apically
through the root canal until all the pulp necroses
 As occurs in all teeth with pulp disease

2 phases for this resorption: Active and inactive phase.

Question 22

How is internal inflammatory resorption diagnosed?

Answer 22

Radiographic appearance. Radiolucent area within the tooth showing enlargement of the root canal space with or without periapical radiolucency.

Question 23

What are the clinical features of internal inflammatory resorption?

Answer 23

Usually same as teeth with pulpless infected root canal systems

PA conditions can vary (chronic apical periodontitis, chronic apical abscess, acute apical periodontitis)

Question 24

How is internal inflammatory resorption differentiated from external invasice resorption?

Answer 24

External invasive resorption is characterised by sub-gingival origin.

Radiolucent areas with poorly defined margins

Very vascular tissue that bleeds easily

Can resemble caries or internal root resorption.

Question 25

How commonly is external inflammatory resorption misdiagnosed as internal resorption?

Answer 25

In a study by Dr Abbott 36% of extensive invasive resorption cases were referred to as internal resorption.

Question 26

What are pink teeth most commonly caused by?

Answer 26

Most likely due to external invasive resorption not internal inflammatory resorption.

Question 27

What is required for internal inflammatory resorption and allows us to confidently assume pink teeth are caused by external invasive resorption?

Answer 27

Internal inflammatory resorption needs necrotic and infected pulp tissue coronal to the resorbing area to stimulate the resorption

There is insufficient space for this in the crown of the tooth.

Question 28

How is internal inflammatory resorption managed?

Answer 28

Remove the pulp (if present)

Thoroughly clean and prepare the root canal

Medicate the root canal system

Question 29

How would the active and inactive phase of internal inflammatory resorption be affected by resorption?

Answer 29

Active phase: would be necrotic coronally, inflamed / connective tissue apically

Inactive phase: Canal will be pulpless

Question 30

What is the aim of cleaning and preparing the root canal?

Answer 30

Aim to remove resorbing cells and blood supply

Copious irrigation especially with 1% NaOCl

Question 31

What is the aim of medicating the root canal system?

Answer 31

Medicate the root canal system to inhibit and destroy the clastic cells and remaining bacteria

Question 32

Which intra canal medicaments should be used for internal inflammatory resorption?

Answer 32

Corticosteroid - antibiotic compound

Ca(OH)2

Combination -> CS-AB paste + Ca(OH)2

Question 33

What are the effects of corticosteroids and tetracyclines?

Answer 33

Corticosteroids: ANti-inflammatory, antiresorptive, promote healing and are biocompatible

Tertracyclines: Anti-microbial, anti-resorptive, reduce replacement resorption and ankylosis, and promote PDL healing

Question 34

What are the antiresorptive effects of CS-AB pastes?

Answer 34

CS: Directly inhibit and prevent attachment of clastic cells

Tetracyclines: Directly inhibit collagenase and clastic cells

Question 35

What are the steps of managing internal inflammatory resorption?

Answer 35

1) Remove the pulp (if any present)
2) Thoroughly clean and prepare the root canal
3) Initially use CS-AB paste for 4 weeks (reduce inflammation, inhibit clastic cells, and anti-bacterial action)
4) Then use Ca(OH)2: Use 2 or 3 times - for 4 weeks each time.
5) Root canal filling - GP and sealer (use a thermoplastic technique for GP or lateral condesnation apically and then warmp GP in resorption defect)

Question 36

Why is Ca(OH)2 used?

Answer 36

Anti-bacterial

Dissolves necrotic tissue

Kills resorbing cells

Inactivates LPS

Encourages hard tissue repair (Esp if the resorptive lesion has perforated the root)

Question 37

How often should RCT treatment of internal inflammatory resorption be treated?

Answer 37

Clinical and radiographic reviews are essential.

Initially 6 months after RCF is completed.

Then every 3 - 4 years for as long as possible.

Question 38

What is the prognosis of internal inflammatory treatment?

Answer 38

Very few studies due to rare occurrence but generally considered to have good or excellent prognosis after root canal treatment if no perforation and if tooth not weakened too much through loss of tooth structure

Question 39

What is the definition of root resorption?

Answer 39

Resorption is either a physiological or a pathological process which results in the loss of substance from the tissue

Question 40

What causes internal inflammatory resorption?

Answer 40

Most commonly associated with trauma and caries + PD disease

Question 41

What is the pathogenesis of internal inflammatory resorption?

Answer 41

Bacteria in the pulp

Odontoblast layer and predentine of the canal wall are damaged

Mineralised dentin gets exposed to clastic cells

Injurious event that is needed to cause this damage is not known but could be anything that irritates the pulp.

Coronal to the resorption defect is necrotic and infected pulp, within the resorptive defect is granulation tissue with clastic cells, and apical to the resorption defect is irreversibly inflamed pulp tissue replaced with periodontal like connective tissue. (If there is no longer resorption then the entire canal will be pulpless and infected)

Progression occurs due to interaction between the bacteria and the remaining apical tissue until it necroses

Bacterial front gradually moves apically through the root canal until all the pulp necroses

Question 42

What are the active and inactive phase of internal inflammatory resorption?

Answer 42

During the active phase: The necrotic tissue and the granulation + clastic tissue moves throughout the root to the apex.

During the inactive phase: PA radiolucency will form enlarging the root canal space. The shape and size are variable. This may or may not have a PA radiolucency.

Question 43

How can external invasive resorption be differentiated from internal inflammatory resorption?

Answer 43

External invasive resorption is often subgingival and can be felt with a probe whereas internal inflammatory resorption can only be seen on radiograph.

Radiolucent area in external invasive resorption often has poorly defined margins whereas internal inflammatory resorption has well defined margins.

External invasive resorption leads to lots of bleeding whereas theres no bleeding caused by internal inflammatory resorption.

External invasive resorption causes pink teeth not internal inflammatory resorption.

Question 44

What does Ca(OH)2 do for internal inflammatory resorption?

Answer 44

Anti-bacterial

Dissolves necrotic tissue

Kills resorbing cells

Inactivates LPS

Question 45

How is internal replacement resorption typically diagnosed?

Answer 45

Often through incidental finding on radiograph. (Irregular enlargement of pulp space, and presence of bone replacing pulp and dentin)

Can be differentiated from external invasive resorption via probing, tube-shift, and CBCT.