oral surgery Flashcards
what does an abscess ALWAYS have?
pus
what might be inside of a cyst
fluid or pus
what is a cyst?
pathological cavity having fluid or semi-fluid contents
is a cyst created by the accumulation of pus?
no
where do cysts most commonly appear in the body
jaw bones
what is a fluid filled cavity created by the accumulation of pus?
abscess
what is a cyst often lined with
epithelium
why do cysts commonly form in the jaws?
because of the epithelial remnants left over from the development of teeth eg dental lamina
what do we have remnants of epithelium in the jaws from?
- development of teeth
- fusion of pharyngeal arches
why are cysts of the jaws often epithelial lined?
because of the epithelial remnants of teeth and pharyngeal arches
are cysts always epithelial lined?
no
what are radicular inflammatory cysts derived from?
root sheath of hertwig
what classification is used for cysts of the head and neck?
WHO 2022 cyst classification
what is the most common cyst in the head and neck?
radicular cyst
what is a radicular cyst associated with
non-vital tooth
where are radicular cysts seen
anterior maxilla
how do cysts in the jaws form
- remnants lie in a little ball of dormant cells in the alveolar bone
- something triggers the ball of cells to start proliferation
- they get to a size where the growth exceeds the amount of nutrition available so the central cells die
- the peripheral cells continue to proliferate while the cells in the middle undergo apoptosis
what is usually the trigger for epithelial remnants that form cysts to being proliferation
bacterial infection
what does the pressure of the expanding cyst cause on the neighbouring bone?
osteoclastic stimulation –> resorption
what type of pressure allows a cyst to expand?
hydrostatic pressure
what can happen if an expanding cyst is close to the buccal plate or palatal shelf?
erosion of overlying cortex
what happens if a cyst erodes through the overlying cortex
can perforate through the mucosa
what drives the expansion of a cyst
hydrostatic fluid
what can a cyst present in the mouth as if eroded through the overlying cortex
- expansion of mucosa
- soft to touch - fluctuant swelling
intraorally, on palpation how would you recognise a cyst?
soft swelling of mucosa
what happens if a cyst expands at a fast rate?
can erode through the mucosa - causing an opening like a sinus
what can happen if a cyst causes an opening like a sinus through the mucosa?
bacteria can get into the cyst cavity and cause infection
what will happen if a cyst becomes infected?
becomes symptomatic
when are cysts symptomatic
when they become infected - generally not until then
what sign can bony expansion of a cyst cause intraorally?
egg-shell crackling - bone breaks to the touch
how are asymptomatic cysts often found
chance finding on a radiograph
what intraoral sign of a cyst will there be if there is only mucosa overlying it and no bone?
fluctuant swelling - soft to the touch
what may be a dental sign of cysts
- missing teeth
- carious teeth
- fractured teeth
- discoloured teeth
- loose teeth
why might teeth tilt because of a cyst
the pressure of the underlying cyst pushes the tooth out of the way
why might a cyst cause teeth to be loose?
underlying cyst may cause bone loss around the adjacent teeth
what is the name for swelling putting pressure on the alveolar nerve?
mental hypoaethesia
what percussion sound will a tooth associated with a cyst make
hollow sound
when would pain occur with a cyst?
infection
what might be a sign of a very large cyst taking over a large portion of the mandibular bone
pathological fracture
how would you know if a cyst is slow growing?
the body will form extra layers of bone over the top of the cyst to try and wall off the hydrostatic pressure
what 4 investigations would be made for a cyst
- vitality testing of teeth
- radiographs
- aspiration of contents
- biopsy
what radiographs would be taken for a cyst of the jaws
- DPT in first instance
- supplement with CBCT
what syringe and needle should be used to aspirate the contents of a cyst
10-20ml, wide bore needle
should LA be given before aspirating a cyst?
yes
what would cyst contents being clear with crystallisation that sparkles indicate?
inflammatory radicular cyst
what would cyst contents being clear with crystallisation that sparkles indicate?
inflammatory radicular cyst
what could blood in the contents of cyst indicate?
intra-alveolar vascular lesion
why would a biopsy of a cyst be taken
- establish which type
- rule out tumours
why is a cyst called “cyst-like radiolucency” clinically?
cannot call it a cyst before a biopsy confirms it
what are the management aims of a cyst?
- eradicate pathology entirely
- minimise surgical damage
- restore function as quickly as possible
what is the treatment of choice for a cyst
enucleation
what are the Tx options for a cyst
- marsupialisation
- enucleation
- both
- en bloc resection
- partial resection
how does a clinician decide between enucleation or marsupialisation
- type
- size
- site
- general medical status (for GA)
what can marsupialisation be in combination with if we want to preserve teeth involved with a cyst
peri-radicular surgery
what is enucleation
complete removal of cyst and lining
how does the body heal after enucleation
- large bony cavity fills with blood clot
- blood clot liquifies
- is replaced by granulation tissue
- replaced by bone
how long does healing after enucleation take
several months
following enucleation, how can closure be achieved?
- primary closure
- secondary closure
how is primary closure of a cyst done after enucleation
suturing the cavity over
how is secondary closure of a cyst done after enucleation
packing the defect, then replacing subsequent packs until the granulation tissue fills the base of the defect to the top
how is primary or secondary closure chosen after enucleation?
size of the cyst
adjacent vitality of teeth
any useful teeth in area
how would you plan the flap when undertaking enucleation
so it doesnt directly overly the osteotomy site - raise flap away from the cyst
how is a cyst accessed if there is still overlying bone
raise flap
osteotomise the site
how is the cyst/cyst lining removed from the defect
curettage
how should the sutures be places after enucleation of a cyst
so they are far away from the osteotomy site
why do we try and eliminate dead space when treating a cyst
- reduce reactionary haemorrhage
- reduce post-op infection
how does post-op infection happen if dead space is left when treating a cyst
the initial blood clot liquifies creating a very nutrient rich source for bacteria
how does a drain placement help with dead space after enucleation of a cyst
the vacuum sucks down the overlying mucosa to minimise the amount of dead space
other than dead space, what else does placing a drain after enucleation help with
reactionary haemorrhage as reduces the volume of blood clot that fills the space
why would a clinician choose to collapse the walls of the cavity after enucleation
converts the cavity shape into a larger shape that mucosa can fall over more easily, minimising the dead space
how can a clinician eliminate dead space after enucleation of a cyst
- biological materials
- layered soft tissue closure
- drain placement
- collapse cavity walls
what can a clinician use to fill the space after enucleation of a cyst
- pts own bone
- bone graft
- pts own muscles
what is the layered soft tissue closure post-enucleation of a cyst
suturing muscle into the area
is layered soft tissue closure post-enucleation of a cyst commonly done
no
what are the advantages of enucleation of a cyst
- complete removal for histology
- once primary closure, heals well without complication
what are the disadvantages of enucleation of a cyst
- large dead space - infection
- recurrence if incomplete removal of lining
- damage to adjacent structures
- weakening of the bone
what may be damaged during enucleation of a cyst
- teeth
- antrum
- nerves eg IAN
what may happen if a very large cyst is enucleated
pathological fracture risk
what is marsupialisation
create a window into the cyst lining to allow shrinkage of the lesion
how is a cyst marsupialised
the raised flap is sutured to the remaining lining
when is marsupialisation the treatment of choice for a cyst
when there is a very large cyst with multiple health teeth
what type of pt might marsupialisation be chosen for regardless of the cyst
older/ frail pt
what is a ‘useful’ tooth that may cause the clinician to choose marsupialisation over enucleation?
tooth that can erupt through the space where the cyst is eg canine, incisor
in marsupialisation where should the flap be planned for
directly over the area of bone we want to remove
what might be used in marsupialisation to help reduce infection
acrylic bung
what might be used in marsupialisation to help reduce infection
acrylic bung
how does an acrylic bung help reduce infection after marsupialisation
blocks orifice to prevent food entering and encourage secondary closure
what type of closure is there in marsupialisation
secondary
what are the advantages of marsupialisation
- avoids path fracture
- good for MH compromised pts that cant have GA
- avoids damage to adjacent structures
- allows useful teeth to erupt
what are the disadvantages of marsupialisation
- can close early causing recurrence
- repeat visits over long period
- manual dexterity and compliance needed from pt
- cannot get definite diagnosis
why might a cyst close prematurely when using marsupialisation
pt non-compliant with bung
why cant we get the full diagnosis when using marsupialisation
lining isnt entirely removed for pathology
what origin are radicular cyst
inflammatory
what % of dental cysts do radicular cysts make up
60
what % of dental cysts do radicular cysts make up
60
where on a non-vital tooth does a radicular cyst affect
apex
what % of radicular cyst can turn out to be a residual cyst
20
name 2 collateral cyst
paradental cyst
mandibular buccal bifurcation cyst
what is the incidence of radicular cysts
60-75%
what is the incidence of dentigerous cysts
10-15%
what is the incidence of a keratocyst
5-10%
what is the incidence of paradental cysts
3-5%
what is the incidence of gingival/lateral periodontal cysts
<1%
what is the incidence of a nasopalatine cyst
5-10%
what is a residual cyst
area of a cyst where the associated tooth has been extracted
what is the Tx for radicular cyst
enucleation with either XLA of tooth or apicectomy following RCT
how are lateral cysts and residual cysts treated
enucleation with either XLA of tooth or apicectomy following RCT
what is the Tx if a radicular cyst is really big and compromised adjacent teeth
marsupialisation +/- enucleation
how is a paradental cyst treated
enucleation + XLA of 8 if impacted
name 5 developmental cysts
- dentigerous
- eruption
- keratocyst
- lateral periodontal
- gingival
where does a dentigerous cyst form
around the crown of unerupted teeth
what does a dentigerous cyst form from
remnants of the reduced enamel epithelium
where is a dentigerous cyst always attached to
ACJ
how is a dentigerous cyst treated for an 8
enucleation and removal of associated tooth
how is a dentigerous tooth treated for any other tooth than an 8
marsupialisation and align tooth with ortho
what is a sign of a CHRONIC cyst
well defined corticated margins
what does no lamina dura indicate with a cyst
acute problem
what should the pt be told about long term outcome if marsupialisation is carried out
defect is often left in the bone
what is the Tx for a keratocyst
enucleation and XLA of tooth
what should the clinician pay attention to when removing a keratocyst
remove all the lining –> high recurrence as daughter cysts in the lining
where do keratocysts commonly form
angle of the mandible
what does a keratocyst form from
dental lamina
what is the problem with enucleation and removing the lining of a keratocyst
lining is very fragile and forms in antero-posterior “finger-like” projections through the trabeculae bone
what is carnoys solution
fixative lining that floods the cavity to fix any of the lining thats left behind
is carnoys solution advocated? why?
no, can fix delicate structures eg IAN
what is cryotherapy in cyst removal?
where the cavity is flooded with sterile saline and the cryotherapy probe is inserted until it freezes
is cryotherapy advocated in cyst removal, why?
debatable - no evidence base
what should always follow removal of keratocysts? and why
- radiographic long term follow up
- high recurrence rate
how were keratocysts previously treated when regarded as odontogenic tumours?
en bloc resection
what does root resorption often indicate in terms of type of pathology
less likely it is a cyst and more likely to be a tumour
what should you do before managing a pathology where there is root resorption
biopsy to determine diagnosis - more likely to be a tumour
what is the other name for gorlin goltz syndrome
nevoid basal cell carcinoma
what does gorlin goltz syndrome cause?
development of multiple keratocytes
what inheritance pattern does gorlin goltz syndrome follow
autosomal dominant
what genetic mutation cause gorlin goltz syndrome
PTCH gene found on chromosome 9
what % of gorlin goltz pts have an odontogenic keratocyst
75%
what is the average age that a pt with gorlin goltz syndrome will develop keratocysts in their mandibel
19
what other bony anomalies does a pt with gorlin goltz have
rib and vertebrae
what other feature of dental significance do pts with gorlin goltz syndrome have
prognathic mandible
what does a lateral periodontal cyst develop associated to
vital tooth
how can you determine the difference between developmental and inflammatory cysts prior to surgery
vitality testing of teeth
what is the Tx of a gingival cyst
enucleation/ excision
what is the most common epithelial non-odontogenic (fissure) cyst
nasopalatine duct cyst
where does a nasopalatine duct cyst develop
incisive canal
what does a nasopalatine duct cyst for from
remnants of the fusion of the pharyngeal arches - sensory organ of jacobson
what symptom is characteristic of a nasopalatine duct cyst
salty taste
what type of radiolucency is often seen with a nasopalatine duct cyst
heart shaped
what is the Tx of a nasopalatine duct cyst
enucleation after establishing vitality of adjacent teeth
how would a nasopalatine duct cyst be accessed
full-thickness palatal envelope flap
where do nasolabial cysts form
in the nasolabial fold between the upper lip and cheek
what is the Tx of nasolabial cysts
marsupialisation
name a non-epithelialise primary bone cyst
staphnes idiopathic bone cyst
what is staphnes idiopathic bone cyst
developmental abnormality
what causes the formation of staphnes defect
ectopic salivary tissues in the concavity of the mandible
which salivary gland causes staphnes defect
sublingual
what is the Tx for staphnes idiopathic bone cyst
none needed
name 2 bone cysts
- aneurysmal bone cyst
- solitary (haemorrhagic) bone cyst
what is the aetiology of aneurysmal bone cyst
unknown
what age group does aneurysmal bone cyst affect
10-20 years
where deos aneurysmal bone cyst appear
mandible
what can be seen histologically in an aneurysmal bone cyst
- mass of blood filled spaces with scattered giant cells
what does currettage of an aneurysmal bone cyst often cause
triggers healing
how is diagnosis of aneurysmal bone cyst determined
biopsy
how is a biopsy of an aneurysmal bone cyst taken
- raise flap
- make osteotomy
- currette out contents
who is a solitary bone cyst often seen in
teenagers
what gender are solitary bone cysts more common in
female
where are solitary bone cysts commonly found
mandible
what will be seen radiographically for solitary bone cysts
large radiolucency arching up between roots of teeth
what is the Tx of a solitary bone cyst
resolve spontaneously
what are solitary bone cysts thought to be caused by
bleed in the bone
what is an ameloblastoma
odontogenic tumour
what are ameloblastomas derived from
dental lamina
is ameloblastoma benign or malignant
benign
what age group are ameloblastomas most commonly seen in
40-50
what % of ameloblastomas are found in the mandible
80
what characteristics do ameloblastoma have
aggressive and invasive
what will be seen radiographically for an ameloblastoma
uni/multi-ocular, defined or diffuse edged, usually displaces adjacent structures
how are ameloblastomas diagnosed
biopsy under LA
what do we need from the biopsy to be able to diagnose ameloblastoma histologically
part of the lining
what are the three subtypes of ameloblastoma
- luminal
- intraluminal
- mural
how are the different subtypes of ameloblastoma differentiated from each other
according to the distribution of the proliferation of the epithelium
how are luminal and intraluminal ameloblastomas treated
conservatively
what mutation causes ameloblastoma
BRAF p. V600E mutations
what is the newest odontogenic lesion that is an epithelial odotogenic neoplasm called?
adenoid ameloblastoma
what is adenoid ameloblastoma composed of
cribriform architecture and duct-like structures frequently including dentinoid
what is dentinoid
dysplastic form of dentine
how many cases of adenoid ameloblastoma have been documented
40
what is the Tx for ameloblastoma (mural)
en bloc resection
