ENDO root resorption Flashcards
what is the definition of root resorption?
a physiological or pathological event mainly occurring due to the action of activated clast cells
what is root resorption characterised by?
the transitory or progressive loss of cementum or cementum/ dentine
what is the onset of root resorption associated with?
significant necrosis of cementoblasts and/or injury to the PDL
what are the 2 phases required to cause root resorption?
injury and stimulation
what types of injury cause root resorption?
mechanical
infection of root canal or PDL
chemical
what types of mechanical injury causes root resorption?
trauma
surgical procedures
excessive pressure (impacted teeth, cyst tumours, ortho tx)
what type of chemical injury causes root resorption?
bleaching agents (30% hydrogen peroxide)
what type of stimulation causes root resorption?
infection
pressure
transient resorption (without a constant stimulus the process if self limiting)
lost systemic and endocrine disease which may cause root resorption?
hypo and hyperthyroidism
calcinosis
gauchers syndrome
turner syndrome
pagets disease
herpes zoster
what type of cells colonise damaged surfaces and initiate the resorptive process?
odontoclasts/ osteoclasts
what are howships lacunae?
depressions of odontoclasts/ osetoclasts
what cells regulate the physiological and pathological resorption of mineralised tissue?
receptor-ligand system RNAKL/RANK/OPG - part of the TNF family
what cells carry the RANK receptor?
osteoclast precursor cells and dendritic cells
what induces the fusion of osteoclast precursor cells into multinucleated cells?
binding of RANKL to RANK
what is the most common cause of resorption?
pulp infection
what are causes of resorption, based on stimulation factors?
pulp infection
PDL infection
ortho pressure
ankyloses
tumour
impacted pressure
what does EIR affect?
the external root surface
what usually causes EIR?
trauma - intrusion, lateral luxation and avulsion
how is EIR diagnosed?
radiographic and CBCT interpretation
how is EIR treated?
removal of necrotic pulp as soon as signs of EIR
calcium hydroxide as an interappointment dressing
most cases, resorption too advanced to treat
where do you find invasive cervical resorption?
on external root surface but can invade root dentine in any direction
develops immediately apical to epithelial attachment in cervical region
what causes ICR?
loss of protective non-mineralised layer at the CEJ - developmental, physical/ chemical trauma
microbial stimulation from gingival sulcus
predisposing factors: ortho, trauma, surgery, intracoronal bleaching
how is ICR differentiated from IRR?
ICR is a periodontally derived form of ERR
what are the clinical features of ICR?
asymptomatic
tooth may look pink
positive sensibility test
tooth will be vital as pulp is protected until late in the process by a layer of dentine and predentine
eventually, the lesion will perforate the canal wall resulting in canal infection and necrosis
what are the clinical classifications of ICR?
Heithersay 1999
class I - small with shallow penetration
class II - close to coronal pulp, no radicular extension
class III - deeper but not beyond coronal third
class IV - extensive beyond coronal third
what are the radiographic features of ICR?
radiolucent area which can be confused with IRR
*use parallax and CBCT for further info
what is the treatment for ICR?
remove granulation tissue from defect with 90% trichloracetic acid
restore with GI, composite or biodentine
RCT if communication with pulp canal
where does IRR originate?
in and affects the root canal wall
follows damage to odontoblastic layer and predentine
what is the aetiology of IRR?
still unknown - mostly a result of trauma
what is required for IRR to continue?
pulp tissue apical to the lesion must have a viable blood supply
eventually the pulp will become necrotic and resorption will stop
clinical appearance of IRR?
extensive resorption can result in pink discolouration of the crown (may be confused with ICR)
radiographic features of IRR?
oval, round lesions any site along root canal usually symmetrical
the outline of the root canal cannot be traced as IRR cavity is continuous with normal root canal walls
treatment for IRR?
RCT if tooth can be saved
lesion difficult to clean (bleeding) and obturate (shape) so can use thermoplastic techniques
what happens if IRR left untreated?
perforation and clast cells can obtain nutrients from surrounding tissues
what is orthodontic pressure root resorption?
apical root resorption can occur as a result of injury originating from the pressure applied to the roots during tooth movement
are teeth symptomatic in the case of ortho pressure root resorption?
teeth are asymptomatic and pulp remains vital unless pressure is such that it disturbs the apical blood supply
radiographic features of ortho pressure root resorption?
shortened roots with no signs of radiolucency in the bone
what teeth does impacted tooth pressure resorption affect?
maxillary canines and mandibular third molars
what type of tumours may cause pressure resorption?
slow growing cysts
ameloblastomas
giant cell tumours
fiber-osseous lesions
what is ankylotic root resorption referred to as?
replacement resorption
what type of injuries may cause ankylotic root resorption ?
in severe traumatic injuries: intrusive luxation, avulsion with delayed reimplantation
how is ankylotic resorption caused?
injury to the root canal is so large that healing with cementum is not possible and the bone comes into contact with the root surface.
osteoclasts are in direct contact with the mineralised dentine and therefore resorption can occur without further stimulation and bone is laid down instead
clinical findings for ankylotic root resorption?
teeth lack physiological mobility and sound metallic to percussion, sometimes in infra occlusion
radiographic findings for ankylotic root resorption?
bone fills the resorption lacuna and there is no radiolucency
treatment for ankylotic root resorption?
no stimulation factor to remove and no predictable tx
prevention - minimise damage to PDL
functional splint can be placed for 7-10 days and RCT to prevent pulpal infection and resorption
