management of deep carious lesion

what does WHO define caries as?

most common non-communicable disease with greater prevalence in pts from disadvantaged social groups

preventable disease - brush x2 day, fluoride

pathological process

breakdown of tooth tissue, enamel and dentine

  • ingestion of sugar

  • fall of pH due to acid prod of bacteria

  • demineralisation of tooth tissue

  • pH 5.5 - critical - liberation of Ca2+ and PO4-

  • pH increases - predisposition of Ca2+ and PO4-

  • equilibrium

proteolytic enzymes which breaks down organic component of tooth tissue

tooth tissue with most organic component - dentine

enamel breakdown means bulk tooth structure of dentine is vulnerable to caries

what is a deep carious lesion?

caries reaching inner quarter of dentine, but with zone of hard or firm dentine between the caries and the pulp, which is radiographically detectable when located on an interproximal or occlusal surface

risk of pulp exposure during operative treatment

extremely deep carious lesion

caries penetrating the entire thickness of dentine, radiographically detectable when located on an interproximal or occlusal surface

pulp exposure is unavoidable during operative treatment

disadvantage of radiograph is its 2D so all info is squashed on one another

CT scan for maxillary and mandibular complex - 3D image

soft dentine: can be excavated with minimum resistance using hand instruments

firm dentine: firm dentine should be resistant to excavation using hand instruments (spoon excavator)

hard dentine: hard dentine should be sound and resistant to probe penetration and scratching

subjective assessment to caries removal

pulpal response to caries

defence system:

  • lays down dentine for protection

  • immune system and puts immunoglobulin in dentinal tissue fluid to kill bacteria

what is dentine pulp?

connective tissue uniquely situated within rigid encasement of a mineralised tissue

if pulp is affected:

responds in two diff ways

mild stimulus (slow progressing lesion/tooth wear) - odontoblasts lay down reactionary dentine

stimulus tells odontoblasts to lay down dentine quicker so work harder - tertiary dentine

strong stimulus (deep rapidly progressing lesion)- odontoblasts die off, stem cells within pulp or circulating stem cells, turn into odontoblast like cells and lay down reparative dentine

strategies in managing deep carious lesion

prevention! - diet, OHI, fluoride use

delivering better oral health

if early carious lesion may stop at preventive measures or something minimally invasive

strategies in managing caries removal in DCL

probably need to cut carious and sound tissue as well

different approaches

any carious lesion going to treat - have to clear ADJ otherwise don’t know how far it progresses, need to see whole periphery of lesion at ADJ, sound ADJ

other philosophies:

non-selective caries removal - complete removal of soft and firm carious dentine from periphery and central aspects of cavity until hard dentine is reached

  • irrespective of potential damage to pulp

selective removal to firm dentine - firm dentine is left only on pulpal aspect of cavity while peripheral carious dentine is removed to hard dentine

  • affected, undergone change due to disease process

  • deepest part of carious lesion - dont get infection

selective removal to soft dentine - soft dentine is left only on pulpal aspect of cavity while peripheral carious dentine is removed to hard dentine

  • trying to get rid of infected dentine

  • leave some soft dentine, diseased tissue

  • more likely to conserve pulp and prevent loss of pulp

effects of surgical exposures of dental pulps in germ free and conventional laboratory rats

conventional rat - normal oral flora - sterile food

germ free rat - gnotobiotic group that had absence of bacteria in mouth

infection that causes problem to pulp

exposed pulp in maxillary molars

killed rats at different periods of times

for those with bacteria - histology of pulps showed that in all cases inflammation of pulp

those that were killed later on showed change in periradicular tissues , pulp had become necrotic

however absence of bacteria showed no inflammation of pulp and dentine bridge formation due to reparative dentine, pulp was regenerating

two different approaches in treating pulp

indirect treatment of the pulp

  • layer of dentine between pulp

  • selective carious-tissue removal in one stage

  • stepwise excavation

direct treatment of the pulp

  • direct pulp cap

  • partial pulpotomy

  • full pulpotomy

  • pulpectomy

step wise excavation

  • remove bulk of caries but not all

  • place therapeutic lining material - calcium hydroxide or calcium silicate cement

  • then place restoration on top

  • wait for therapeutic material to have change on dentine - causes remineralisation of tooth tissue, kills bacteria, leave for period of time (3 months)

  • stimulate odontoblasts to regulate themselves

  • increase thickness of dentine between base of cavity and pulp itself

  • go back in thru stepwise excavation and remove some of caries as now increase thickness between pulp

or selective carious-tissue removal in one-stage

compared with total caries removal - kill less pulps

direct treatment

direct pulp capping - expose tooth iatrogenically or caries exposure

application of a biomaterial directly onto exposed pulp, prior to immediate placement of a permanent restoration

pulpotomy - removal of some or all of coronal pulp tissue after exposure, followed by application of a biomaterial directly onto remaining pulp tissue prior to placement of a perm restoration

partial pulpotomy or full pulpotomy

pulpectomy - total removal of all pulp from root canal system followed by root canal treatment, prior to placement of a permanent restoration

sign of inflammation of pulp - bleeding, hyperaemia

concerns about vital pulp therapy

success rate of pulp capping is high to start off with but goes off after time

partial pulpotomy and full pulptomy has high success rate as removing inflamed tissue and getting back to sound tissue

why maintain pulp vitality?

  • pulpless teeth have no defence system or ability to protect themselves

  • proprioceptive function of the pulp - tells jaw to stop adding load when biting together

  • apexogenesis

  • endodontic treatment of the necrotic pulp is technically demanding and not always successful

  • endodontically treated teeth are prone to fracture as less dentine

injured pulp - injury from

  • caries

  • trauma

  • dental treatment

diagnostic challenge

talk to patient - socrates

s - site, where is pain

o - onset, when did pain start and was it sudden or gradual

c - character - what is pain like, ache, stabbing

r - radiation - does pain radiate anywhere else

a - associations - any other signs or symptoms associated with pain

t - time course - does pain follow any pattern

e - exacerbating - does anything change the pain

s - severity - how bad is the pain

diagnostic tests

special tests - types of pulp tests, radiographs

pulpate buccal sulcus and feel around root end and see if pt has any inflammation

tap tooth with end of mirror - does it hurt

maybe tap from side

pulp tests

^^not v accurate

pulp (vitality) testing

determining viability of the pulp

  • pulp testing

  • both normal and inflamed pulps give a positive result

  • pulp test useful for broad sifting

types of pulp tests

  • thermal

    • cold

    • hot

    • test control teeth so get an idea of response

  • electrical

  • test cavity

thermal tests

  • cold most useful - safer

  • hot - not routine, very useful when only symptom is heat sensitivity and pt cannot identify tooth

  • thermal tests gives an indication of pulp vitality and state of that pulp - preferred from an endodontic point of view

  • baseline

  • looking for - response time, intensity, duration

cold tests

  • spray cotton wool ball held in tweezers

    • ethyl chloride

    • endo ice

  • ice stick - start with last tooth and work forwards, wait 30-60s before testing next tooth to allow for delayed response

hot tests

  • gutta-percha heated in bunsen

  • if above inconclusive, isolate teeth one by one under rubber dam and bathe with hot water in large disposable syringe

response to thermal testing

  • slight +

  • moderate ++

  • severe +++

  • no discomfort -

  • no response N.R.

  • explain procedures to patients

electrical

  • not as sophisticated as seems

  • perio seem to prefer them

  • analytic pulp tester

technique

  • dry tooth

  • prophy paste to probe tip

  • get pt to complete circuit - pt lets go of handle when feels response

EPT used if teeth do not respond to thermal test and do not have periradicular lesion on radiograph

false positive pulp tests

  • signal conduction from adjacent tooth

    • moisture

    • contacting amalgams

  • partial vitality

    • multi rooted teeth

    • single rooted teeth

  • open apices (stimulation of sensory nerves in periodontal complex)

  • patient anticipation/apprehension

false negative pulp tests

incomplete circuit - poor contact with tooth surface under test

too well insulated

  • secondary/tertiary dentine in pulp chamber

  • sclerosed canals

radiographic evidence

grossly carious tooth

  • periapical condition

  • rough extent of carious lesion

  • response of pulp to irritation

periapical condition

  • widening of ligament space

  • loss of lamina dura

  • periapical radiolucency

rough extent of carious lesion

  • occlusal

  • approximally

response of pulp to irritation

  • death

  • shape and size of pulp chamber - asymmetric pulp when an assault

  • reactionary/reparative dentine

material directed therapy of exposed pulp

  • calcium hydroxide - since 1920’s, effective

  • resin bonding agents - don’t work

  • mineral trioxide aggregate (MTA)

  • biodentine et al

pulpal responses to CSCs

CaOH2

  • materials next to pulp

  • lots of inflammatory cells next to CaOH2

  • some dentine bridge - reparative dentine formation

MTA

  • no pulp inflammation

  • dentine bridge formation

calcium silicate cements

bulk calcium silicate cements

  • portland cement based

  • synthetic

film (sealer) calcium silicate cements

  • portland cement based

  • synthetic

pulp capping MTA vs calcium hydroxide

MTA performs alot better than calcium hydroxide in pulp capping

irreversible pulpitis - root canal therapy or extraction

however MTA agents are successful in pulpotomies

broad protocol for VPT

  • indications - any vital pulp

  • isolation - dental dam

  • haemorrhage control - 5 mins

  • pulpal lavage - Na0Cl

  • wound dressing - calcium silicate cement

  • restoration - restorative first principles