Seminar 9: Resorption Flashcards
What is resorption?
Physiological or pathological process
Loss of dentine and or cementum
By clastic cells
What protects dentine and cementum from resorption?
Non mineralised components: pre dentine/pre cementum/PDL
Cells: odontblasts and cementoblasts
What feature is specifically protects cementum from resorption ?
Hyaline layer of Hopewell-Smith
How does pre dentine / cementum and PDL protect against resorption?
They secrete anti invasion factors preventing attachment of clastic cells to hard tissue surface
How does hyaline layer of Hopewell- Smith protect against External Root Resorption?
Covers dentinal tubules
Protects them against noxious stimuli and irritants
What type of cells are clastic cells?
Multinucleated giant cells
What cells resorb bone?
Osteoclasts
What cells resorb dentine and cementum?
Dentinoclasts
According to Patel et al 2010 name the stages of resorption
Attachment
Clear zone formation
Podosome formation
Resorption
What happens in the attachment stage of resorption?
Patel et al 2010
Attachment of clast to hard tissue surface
What happens in the clear zone stage of resorption?
Reorganisation of myoskeleton of clastic cell allowing intimate contact of cell membrane to resorbing surface
What happens in the podosome formation stage of resorption?
Finger like projections creating a ruffled border to increase surface area to take place
What happens in the final stage of resorption?
A highly acidic environment is created leading to hard tissue breakdown
What are the requirements for resorption to take place?
- damage to predentine/cementum and PDL
- Protection from osteoblasts/cementoblasts/fibroblasts is inhibited
- Colonisation of denuded hard tissue surface by clastic cells
How can pre dentine become damaged?
Trauma
Restorative materials/procedure
Vital bleaching
Ortho
Perio disease
How can precementum become damaged?
Trauma
Ortho
Orthognathic surgery
Perio surgery
Bruxism
Heat during RCT obturation
Once an injury has occurred how are dentinoclasts and osteoclasts activated ?
Acute inflammation which initiates resorption
What are the causes of chronic inflammation which can fuel resorption?
Pulpal: bacteria in the pulp or their products leaking via cracks or restorative materials
Perio: sub gingival plaque, Ortho, root canal infection
Resorption can be sustained by?
Chronic inflammation from pulp or PDL
How can resorption be classified?
Site
Aetiology
Pathogenesis
What are the two types of resorption by site?
Internal
External
What are the types of internal resorption?
-Transient
-Progressive (sustained by bacteria or their products OR by cytotoxic materials in pulp therapy)
-Replacement
What are the types of external resorption ?
-transient
-progressive ER without persistent inflam
-progressive with persistent inflammation by bacteria / foreign material / SG plaque
-progressive ER idiopathic
-progressive ER systematic disease
-replacement resorption
What percentage of teeth suffer from internal resorption ?
2% perm teeth
What is the pathophysiology behind IR?
Damage to predentine and odontoblast layer
How may IR present clinically ?
Pink spot if takes place in pulp chamber
How does IR appear radiographically ?
Well circumscribed symmetrical oval lesion
Continuous with root canal
Chamber CANNOT be seen through lesion
With parallax how does IR appear?
Central
What maybe seen on a X-ray with IR apical to resorption lesion?
Radiopaque calcified mass
Would you expect to get positive or negative pulp test response in IR?
Can be vital
Maybe negative or coronal pulp necrotic
When do patients typically get symptoms during resorption ?
Once the pulp becomes necrotic and infected
Which teeth are more commonly affected by IR?
Teeth following auto transplant
When would you typically see apical internal resorption ?
In teeth that have periapical lesions and associated with inflammatory external resorption
What concentration of NaOCL would you use in IR cases?
5%
Need to start RCT ASAP to avoid perforations
What is the pathophysiology behind progressive internal resorption?
- Bacterial invasion causing inflammation
- Bacteria invade pulp causing necrosis
- Blood supply is provided by vital pulp tissue apical to resorption
When does progressive internal resorption cease?
Once pulp becomes necrotic
In progressive internal replacement what tissue can be found inside the chamber ?
Dentine / bone like
Calcified material
In what instances are you more likely to see external resorption ?
Severe trauma / injury
In transient external resorption how May this appear radiographically?
Small indentations
Which cells/layer have been damaged in External transient resorption?
Precementum
Cementoblasts
How can precementum or cementoblasts become damaged
trauma
Orthodontic surgery
Orthognathic surgery
Periodontal surgery
Bruxism
Excess heat use in obturation / RCT
What is the clinical presentation of transient ER?
Self limiting
Asymp
How does transient ER appear radiographically ?
Delineations lined by intact PDL
What is the treatment required for transient ER?
Nil
What is progressive external resorption without persistent inflammation also known as?
Replacement resoprtion
In which cases would you more commonly see ER without inflam/RR?
Usually luxation injury e.g avulsion
When damage to more than 20% of cementum occurred
In RR or ER without inflammation what happens to the sites where resorption taking place?
Osteoclasts resorb bone and denuded root surface
Osteoblasts deposit bone and dentine in areas of resorption
How does RR present clinically?
High pitched sound when tapped
often asymptomatic
No physiological tooth movement
In a child how may RR present clinically as the child ages?
Infraocclusion
How does RR appear radiographically?
No PDL space ad mottling effect between bone and cementum
How do you manage RR following avulsion?
When teeth are avulsed RCT them within 7-14 days
Progressive inflammatory ER can be sustained by what?
Root canal infection
Pressure
SG plaque
Foreign body
What is the aetiology begin progressive ER sustained by inflammation?
- Root canal infection causes inflammation within PDL
- Apical CDJ is the and risk of resorption
- Necrotic bacterial products diffuse through dentinal tubules fuelling resorption
How does inflammatory Progressive ER present caused by root canal infection present clinically?
CAP
Negative pulp
May have mobility
how does inflammatory Progressive ER caused by root canal infection present radiographically?
Irregular outline
Moves in same direction as parallax
Root canal outline remains intact
How does inflammatory Progressive ER present caused by pressure present clinically?
Shortened roots
Normal PDL space
Mobile tooth
Vital pulp
How do you manage inflammatory Progressive ER present caused root canal infection?
RCT and may require long term CaOH dressing
how do you manage inflammatory Progressive ER present caused by pressure?
Removal of pressure source
How does inflammatory Progressive ER present caused by foreign body and SG plaque develop?
removal of cementum following root planing allows dentinoclasts to adhere to root surface
How does inflammatory Progressive ER present caused by foreign body/SG plaque present clinically?
Asymp initially but may develop into pulpitis
Non carious cavity may be probed subgingivally
MAY see pink spot if enamel undermined
How do you manage inflammatory Progressive ER present caused foreign body/SG plaque?
Surgical exposure
Remove resorptive lesion
restore with defect with GIC
MAY req RCT
Periradicualr EIRR caused by trauma is caused by what?
intra canal bacteria and their products
Why are younger teeth at greater risk of Periradicualr EIRR?
Wider tubules and thinner dentinal walls so easier for bacterial products to diffuse through
Name three systemic diseases associated with progressive RR
Herpes Zoster
Hypoparathyroidism
Radiotherapy
How does Herpes Zoster cause progressive RR
Internal resorption
Damage to nerve endings in pulp can lead to pulpitis
How does hypoparathyroidism cause progressive EIRR?
External
Hypomineralised dentine at greater risk of resorption
What is invasive/external cervical resorption? (ICR)
Form of external resorption
ONLY HAPPENS CERVICALLY
How does external cervical resorption develop?
damage to PDL + sub epithelial cementum
Which teeth are most commonly effected by external /invasive cervical resorption?
Mainly seen in max incisors
Mainly due to highest risk of trauma and damage from parafunctional habits
Is it true that in ICR there can be both destructive and reparative phases happening simultaneously?
TRUE
What are the predisposing factors for ICR?
+++intra-coronal bleaching esp at higher concentrations
++Trauma
+ Ortho
Can also be idiopathic
How does ICR present clinically?
Initially asymptomatic and responds to pulp tests
May see pink spot
Tooth ma also appear grey in later stages representing pulp necrosis
May detect SG non carious cavity with vascular tissue present
How does ECR present radiographically?
Bone loss around lesion
Pulp seen through resorption defect
Usually a mottled appearance
With parallax views how do internal resorption lesions change?
They do not change as X-ray tube head moves
With parallax views how do external resorption lesion change?
They change as tube head moves
How do you manage ICR?
expose resorption
can use trichloroacetic acid 90% to aid removal of lesion
+/- RCT or monitor pulp status
How can ICR lesions be classified?
Patel system
Heithersay 1999 system
Both based upon the level of lesion
Circumferential involvement
Proximity to root canal
List factors causing persistent pupal inflammation
Bacteria and their products leaking into pulp via cracks
Bacteria and their products in pulp proper
Cytotoxic materials
List factors causing persistent PDL inflammation
SG plaque
External pressure e.g. ortho/cyst
Root canal infection via foramina and denuded root surfaces
