Third Molar Flashcards
eruption
- approx 18-24yrs, varies
- may still be present and begin to erupt in elderly/edentulous pt
CO denture rocking/no longer fits
crown and root calcification
- crown: begins 7-10yo, completed by 18yo
- root: completed btw 18-25yo
stats of missing
- at least 1 missing in 25% adults
- maxilla
- female
guidance and their summary
SIGN 43 2000 - must justify the need of surgical removal
NICE 2000 - discourage removal unless pathology assoc.
most up to date (currently in use):
FDS RCS 2020 (Faculty of dental surgery, royal college of surgeons) - change from soley therapeutic approach to mixed intervention
nerves at risk during SR L8s
lingual
IAN
mylohyoid and long buccal - less common and effects less obvious
location of lingual n
varies
- lies on superior attachment of mylohyoid muscle
- at level of lingual plate in 15-18%
- 0-3.5mm medial to mandible
impacted meaning
tooth eruption is blocked
- full/ partial functional position
incidence of impacted lower third molar
around 50%
consequence of impaction
- caries
- periconronitis
- cyst formaiton
U removal indications
cheek biting/buccally erupted overeruption traumatising L operculum PE and impacted non-fct pt undergoing GA
therapeutic indication of wisdom extraction
- caries (8/7)
- pericoronitis
- periodontal disease (7d)
- local bone infection
- Dentigerous cyst
- tumours
- external root resorption of 7/8
SIGN vs NICE
SIGN - ≥1 episode of infection
NICE >1
imaging
OPT
(+/- PA)
+/- CBCT (3D relationship to nerve)
clinical assessment of M3M
eruption status - how many cusps seen
PD status - pockets distal to 7?
TMJ - rule out TMJ, similar pain to pericoronitis
exclude other causes
local infection
caries/resorption
occlusal relationship
regional LNs
any associated pathology
degree of surgical access
working space
STs
Types of imapction
- plus transverse (buccal / lingual)
- aberrant ( in odd place)
working space
distance between L7 and ascending ramus
radiological assessment
- orientation and position (impaction)
- impaction depth
- relationship to IDC/MS
follicular width
working distance
crown - size, shape, caries
roots - number, morphology, apical hooks
bone levels
adjacent tooth
any surrounding pathology
- dentigerous cyst
- loss of bone distal to crown
when to consider when follicle turning to dentigerous cyst?
if follicle > 3mm size
3 key radiographic signs of M3M - possible increased risk to IAN
diversion/deflection of canal
darkening of root where crossed by canal
interruption of tram line / lamina dura of canal
8 radiographic signs of possible increased risk to IAN - M3M removal
diversion/deflection of canal darkening of root interruption of white lines/LD of canal deflection of root narrowing of IDC narrowing of root dark and bifid root juxta apical area?
juxta apical area
well-defined radiolucent area adjacent that isn’t related to PA pathology
can appear corticated
lamina dura round tooth intact
lateral to root rather than apex
what is the most common orientation of impaction? M3M
mesial 40%
what is orientation of impaction measured against?
the curve of spee
- curve of occlusal plane
- draw lines through long axis of 7 and 8 and compare
what are the types of depth of impaction and what does it indicate?
- superficial - 8 crown relate to 7crown
- moderate - 8 crown to 7 crown+root
- deep - 8 crown to 7 root
- amount of bone removal required
why is L. disto-angular 8s difficult to extract?
- bone removal required (ascending ramus dense bone)
- vector of movement during elevation is distal so tooth has nowhere to go
- roots of 8 often v close to roots of 7 - can make it difficult to get an application point to elevate (also care not to damage 7 roots during mesial bone removal)
pericoronitis definition
- Inflammation around the crown of a PE tooth
- need communication with oral cavity
if not visible careful probing 7d for comunication
pericoronitis aetiology
- food and debris get trapped under operculum - inflammation/infection
S+S of pericoronitis
pain swelling (IO or EO) bad taste pus discharge occlusal trauma to operculum ulceration of operculum evidence of cheek biting foetor oris limited mouth opening dysphagia pyrexia malaise regional lymphadenopathy
which LNs are often raised and palpable in pericoronitis?
SM or upper cervical chain
pericoronitis EO swelling
severe cases
often at angle of mandible and may extend into SM region
spread of infection of pericoronitis
laterally into cheek
distobuccally under masseter (submasseteric abscess and profound trismus)
sublingual
SM
area around tonsils and paraphyaryngeal space (dysphagia)
less commonly - through anterior pillar of fauces area into SP (dysphagia)
tx of pericoronitis
- I+D of pericoronal abscess if required +/- IDB
- irrigation
- warm saline in 10-20ml syringe w blunt needle
under operculum - ext U8 if traumatising operculum
- usually no ABs unless severe
systemically unwell
EO swelling
immunocompromised e.g. diabetic - if large EO swelling, systemically unwell, trismus, dysphagia - refer to MF/A+E - phone first for advice
- pt instructions
- no removal of 8 until pericoronitis resolved - removal of periculum not recommended - will just grow back
pericoronitis pt instructions
freq warm saline or MW
- teaspoon salt warm water
analgesia
keep fluid levels up and keep eating (soft diet)
pericoronitis astringent/antiseptic
e.g. talbots iodine - applied with college tweezers - one drop beneath operculum
not if have incised a localised pus collection
not on fresh/open wounds
ext of L8 pericoronitis
generally don’t ext affected 8 until acute episode has resolved
- unless in hospital with GA for I+D - ext tooth then
operculectomy
prev
no longer carried out - often grows back
predisposing factors for pericoronitis
PE (usually 20-25yrs) and vertical or distoangular impaction
opposing maxillary 8 causing mechanical trauma contributing to recurrent infection
upper resp tract infections, stress and fatigue PC
poor OH
Previous episodes of pericoronitis
insufficient space between ascending ramus of L jaw and distal aspect of 7
white race
a full dentition
SDCEP pericoronitis initial management (emergency ?)
determine if airway compromised - pt unable to swallow own saliva/push tongue forwards out of their mouth
- yes: emergency care/999
SDCEP pericoronitis adults
recommend analgesia
no ABs unless signs of spreading infection (e.g. limited mouth opening, facial swelling), systemic infection, IC pt, persistent swelling
rinse 0.2% CHX MW
seek urgent dental care
SDCEP pericoronitis children
optimal analgesia
soft toothbrushing around area
rinsing mouth after food
pericoronitis SDCEP subsequent care for adults
US scaling/debridement to remove any foreign body, under LA
irrigate 0.2% CHX MW
ext if repeated episodes
ext/adjust an opposing tooth where there is trauma to the inflamed operculum if the position of the tooth suggests it is unlikely to achieve fct in future
local measures for pericoronitis
irrigation and debridement
1st line ABs for pericoronitis
metronidazole 400mg, 9 tablets, x3 daily
avoid alcohol, not if on warfarin
2nd line Abs for pericoronitis
amoxicillin 500mg, 9 capsules x3 daily
- hypersensitivity reactions
RCS FDS guidelines - factors regarding M3M status
pt age and medical status (complications and recovery)
risk of complications (IAN/leaving M3M in situ)
pt access e.g. military
opposing contralateral 8 if having GA
RCS FDS guidelines - diseased/high risk of disease development and asymptomatic
assess likelihood of disease development - high/low risk
high risk - consider surgical
if any doubt and tooth has higher risk of surgical complications - active surveillance until symptoms develop/early disease progression has been proven
quiescent pathology may inc undiagnosed 7/8:
- caries
- PDD
- resorption (internal or external)
- cysts or tumours
RCS FDS guidelines - diseased/high risk of disease development and symptomatic
consideration for therapeutic exts is indicated for:
single severe acute or recurrent subacute pericoronitis
unrestorable caries of M3M or to assist Rx of adjacent tooth
PDD compromising M3M and/or adjacent tooth
resorption of M3M and/or adjacent tooth
fractured M3M
M3M periapical abscess, irreversible pulpitis or acute spreading infection
surrounding pathology (cysts/tumours) associated w M3M
tx to be considered:
- therapeutic removal of M3M (or coronectomy)
- removal of U3M
RCS FDS guidelines - non-diseased/low risk of development and asymptomatic
clinical review and radiographs if indicated. Make assessment of risk of disease and review interval
factors for consideration for prophylactic removal
- medical: planned medical tx/therapy that may complicate the likely surgery of M3Ms inc: pharmaceutical therapy (bisphosphonates, antiangiogenics, chemo), radio of HandN, immunosuppressant therapy
- surgical: M3M lies within perimeter of a surgical field: mandibular fractures, orthognathic surgery, resection of disease (benign and malignant lesions)
RCS FDS guidelines - non-diseased/low risk of development and symptomatic
leave deeply impacted M3Ms with no associated disease
manage other diagnoses causing pain in the region
- TMD
- parotid disease
- skin lesions
- migraines or other primary headaches
- referred pain from angina, cervical spine
- oropharyngeal oncology
RCS FDS guidelines - main reason for removal
infection
RCS FDS guidelines - significant radiological signs of risk to IAN
diversion of IAN canal
darkening of root
interruption of cortical white line
RCS FDS guidelines - CBCT
not routinely
evidence it doesn’t offer benefit in reducing incidence of IAN neurosensory disturbance
- if findings expected to alter tx decision
- see if direct contact or bony wall between
RCS FDS guidelines - common tx
referral clinical review removal of M3M ext of U8 coronectomy
RCS FDS guidelines - less common tx
operculectomy
surgical exposure
presurgical ortho
surgical reimplantation/autotransplantation
RCS FDS guidelines - comment on NICE 2000
discouraged prophylactic removal
- but evidence this isn’t always best - delays surgery and damage to 7
RCS FDS guidelines - why do coronectomy?
if close to IAN, reduce risk of injury
RCS FDS guidelines - coronectomy risks
pain and infection
potential future need for removal of the roots
RCS FDS guidelines - coronectomy contraindications
non-vital caries with risk of pulpal involvement tooth mobility apical disease association with cystic tissue that is unlikely to resolve if root left in situ tumours IC prev radio to H+N/tx before radio NM disorders diabetes unable to return for tx easily should complications occur
RCS FDS guidelines - CHX benefits
effective (gel more) - prevents alveolar osteitis
RCS FDS guidelines - adverse events of CHX
staining altered taste burning sensation hypersensitivity mucosal lesions
RCS FDS guidelines - routine radiographic screening of UE8s with no disease or symptoms
not recommended
RCS FDS guidelines - clinical review
just reviewing S+S
only xray if clinical S/S of disease
- routine BWs should inc distal of 7
RCS FDS guidelines - active surveillance
non-op management strategy for retained M3Ms - prescribed, regularly scheduled set of follow up visits that inc both clinical and radiographic examinations
explaining procedure to pt
flap - small cut in gum to get access
sectioning - cut tooth into smaller pieces to remove it
possible drilling
sutures (stitches) - whether dissolvable
intra-op complications
fracture of tooth, root, alveolar plate, tuberosity TMJ dislocation haemorrhage ST damage OAC loss of tooth/root broken instruments damage to Rx in 7 if edentulous/atrophic mandible, aberrant 8 close to lower border, large cystic lesion associated w 8 - explain risk of jaw fracture - because your L jaw is thin - it is rare but could break, we would arrange for it to be sorted - break can sometimes happen post-op direct trauma to IA NV bundle
loss of tooth/root into:
lingual space
MS
pterygoid space
ST damage
puncture/laceration with instruments - gingivae/FOM/palate
burns - from handpiece resting on L lip
crush - papillae/lip
tears - gingivae/palate
damage to Rx in 7
if this happens temp Rx placed at time then back for permanent Rx
post-op complications of M3M extraction
pain
swelling
bruising
bleeding
infection with pus
jaw stiffness/limited mouth opening
dry socket (localised osteitis)
Nerve damage :
- numbness (anaesthesia) or
- tingling (paresthesia) of L lip, chin, side of tongue
usually temporary - recovery up to 18-24m - dysaesthesia (rare)
- reduced sensation - hypoaesthesia
- heightened sensation - hyperaesthesia
altered taste (rare)
rare post-op complications
Osteomyelitis
Osteoradionecrosis
MRONJ
actinomycosis
how to explain dry socket to a pt
a slower healing painful socket
1-2wks to settle
come and see us
why can altered taste result?
chorda tympani arises from facial nerve, taste buds from ant 2/3 tongue, carries fibres via lingual nerve
how to explain dysaesthesia to a pt
painful, uncomfortable, unpleasant sensation of L lip, chin, tongue, sometimes neuralgic type pain
should you do CBCT?
if concerns of close proximity from radiograph - offer CBCT
- but would scan change tx?
damage to IDN stats
temporary (weeks/months) - average 10-20% permanent - average 1% and under - higher 5% and above if IDC and roots close proximity
discussing risks to nerves
can recover up to 18-24m but after this time not much hope for any further recovery
often discuss warnings as one e.g. lip/chin and side of tongue - %s similar
if close proximity suggested by xray/confirmed by CBCT - explain in relation to the nerve that supplies lip/chin/teeth/gums on that side
explain risks to side of tongue remain average because nerve runs in STs and can’t be seen on xrays
talk about IDC to pt (canal nerve runs in) - can only see bony canal
tx options
do nothing - monitor - may need local measures - irrigate, review, pt advice, risk of recurrence, food trap (surgical) extraction CBCT coronectomy
surgical access - flap design principle
max access with min trauma
larger flaps heal just as quickly as smaller ones
wide-based incision - circulation
use scalpel in one firm continuous stroke
no sharp angles
adequate sized flap
flap reflection should be down to bone and done cleanly
minimise trauma to papillae
no crushing
keep tissue moist
ensure flap margins and sutures will lie on sound bone
ensure wounds aren’t closed under tension
aim for healing by primary intention - minimise scarring
stages of surgery of M3M ext
anaesthesia access bone removal and tooth division as necessary debridement suture haemostasis POIs post-op medication
access
buccal mucoperiosteal flap
+/- lingual flap (debate)
ST retraction/reflection
access
protect STs
retraction
should be on bone at all times not on STs - needs to go under periosteum
avoid dissection occurring superficial to periosteum
- reduce ST bruising/trauma
may get post-surgery tingling due to pressure on nerve (temp)
what facilitates retraction?
flap design
where should you commence flap-raising?
commence flap raising at base of relieving incision (already gaping/bone visible)
instruments for ST retraction
minnesota retractor
rake retractor
howarth’s periosteal elevator
instruments for ST reflection
Ash periosteal elevator
Howarth’s periosteal elevator
Curved Warwick james elevator
Mitchell trimmer
most difficult reflection - reflect with min trauma
papilla - tend to be well-tethered - try to release it before proceeding with reflection distally (avoid tears)
mucogingival jct
why raise flap?
access to surgical site
improve visibility, visualise application point
facilitate bone removal
flap considerations
important structures (esp for relieving incision) e.g. nerves
blood supply and healing
aesthetics
ease of suturing post-op
flaps and papillae
need to either include or exclude papillae
atraumatic/passive retraction
rest firmly on bone
aware of adjacent structures e.g. mental n
3-sided flap
Distal relieving incision - runs out buccally to avoid RM pad as sometimes lingual nerve runs there
intracrevicular incision
mesial relieving incision
- better to include papilla as easier to suture back up
lingual flap and risk
variable use
depends on procedure, visibility, access, amount and area of bone removal and surgeon
can lead to stretching of lingual n which runs close to lingual aspect of L8s
more morbidity with less experienced operators
envelope flap
Pros:
- easier to suture back
- lower risk of damage to vital structures
- Reduced scarring
- wider base assures vascularity
Cons:
- reduced access, challenging to reflect
- tearing
- periodontal damage and recession due to sulcular incision
what blade to cut a flap?
number 15
how to cut a flap?
incise with firm continuous stroke
- feel area with finger first
- pen grip
- finger rest on sound support
- use non-dominant index finger to apply tension to mucosa
full thickness through mucosa and periosteum to bone
crevicular incision
hold scalpel in LA of tooth
blade kept immediately against tooth surface
relieving incision
typically anterior to papilla
draw blade downward/forwards across mucogingival jct
draw blade forward more horizontally having crossed MGJ (to level of apices of teeth)
- to make wider base so better blood supply
drilling
electrical straight handpiece with saline cooled bur
- avoid surgical emphysema (air driven/ turbine) - can get infected
round or fissure SS (often bone) and tungsten carbide (often teeth) burs
protect STs
buccal gutter
start distal (just in front of lingual plate) and bring bur buccally and mesially for safety of lingual n (prevent drill slipping into lingual space)
on buccal aspect of tooth and onto distal aspect of impaction
aim - deep narrow gutter (at least as deep as bur head)
- need to get to bleeding cancellous bone
irrigate - visibility/avoid bony necrosis
away from important structures where possible
usually create gutter extending MD with position of application point dependant on root morphology/access
aim of bone removal
allow correct application of elevators on M and B of tooth, better visual access
when would you section a tooth?
if tooth removal still not possible with elevators +/- forceps and adequate bone removal
horizontal tooth sectioning
make cut higher than for a coronectomy so easier to get roots
above CEJ
only drill approx 5/6 through - leave E to protect adjacent structures then use and twist elevator to snap. Lever off
vertical tooth sectioning
works best on 2 rooted teeth
elevate M+D aspects separately
be v careful of roots of 7
occ need to section each root
lingual split technique
old technique
prev used under GA, often in younger pts
requires lingual flap
lingual wall of 8 socket removed using a mallet and chisel
can remove tooth in one piece by rotating it lingually
takes away some bone behind tooth
- good for distally impacted teeth
forceps commonly used for L
molars, cowhorns, universal, roots
forceps commonly used for U
8s, molars, universal, roots, Bayonet
types of debridement
physical
irrigation
suction
physical debridement
bone file/handpiece to remove sharp bony edges
Mitchell’s trimmer/Victoria Curette to remove ST debris
don’t scrape right at bottom of socket - risk IDN
debris and any follicular or granulation tissue from chronic infection should be curetted
- esp if hidden behind 7
irrigation debridement
sterile saline into socket and under flap
must irrigate below flap before you reposition it
suction debridement
aspirate under flap to remove debris
check socket for retained apices etc
2 methods of suturing
flap closure
anatomical repositioning
When do you do flap closure
some suture flap across socket to lingual side, effectively closing the wound completely
- do if on bisphosphonates/MRONJ risk
anatomical repositioning
most prefer to return flap to its original position, leaving a socket
aims of suturing
reposition tissues cover bone prevent wound breakdown achieve haemostasis encourage healing by primary intention
how to suture flap
usually use mesial suture first as your positioning suture
- can redo it more securely at end
need suture in each papilla
put a suture in the vertical relieving incision if risk of bleeding
normally use resorbable
post-op advice
pain
- expect it - take analgesia before LA wears off
aid healing
- don’t rinse for several hrs, then hot salty MW
- softer/cooler foods for rest of day, softer foods for next
week, eat on other side
- don’t explore socket with fingers/tongue
- be careful not to bite/burn L lip whilst numb
- brush rest of teeth as normal
- no smoking/avoid as long as can - increased risk of dry
socket regardless
- CHX MW x2 daily - not straight after brushing/around
eating
- avoid alcohol and exercise that day (increase bp - bleed)
deal w bleeding
- damp gauze/tissue and bite for 20-30mins
- contact details - you/A+E
other symptoms to expect
- swelling - peak 48hrs, resolves 7-10days, if develops
after 2-3 days likely infection, ice packs 5mins on off for
1hr that day
- bruising - settles 1-2wks
- jaw stiffness/limited opening, usually settles 1-2wks,
keep eating and drinking
sutures
- usually resorbable - may take a few days up to 2 wks to
resorb
- if non-resorbable (prolene) - warn pt they need removed
*contact details
indications for coronectomy
high risk of IAN injury
vital M3M
healthy non-IC pt
access to care for (and understanding of) related coronectomy risks
Tara Renton paper 2005
Randomised controlled trials
shows much lower risk to IAN with coronectomy compared to SR
principles of coronectomy
remove all enamel
tooth roots must not be mobile after decoronation
smooth finish to decoronated tooth and surrounding bone
what is coronectomy?
alternative to SR of entire tooth when there appears to be an increased risk of IAN damage with SR
crown removed with deliberate retention of root adjacent to IAN
aim of coronectomy
reduce risk of IAN damage
risks of coronectomy
if root is mobilised during crown removal the entire tooth must be removed (more likely with conical fused roots)
leaving roots could result in infection (rare)
can get a slow healing/painful “socket”
roots may migrate later and begin to erupt through the mucosa, may require ext
Abs
not used routinely
- consider for prolonged, difficult procedures or in IC pts e.g. diabetic
can administer pre, peri or post op
under GA sometimes one IV dose given peri-op
amoxicillin/metronidazole - 3/5/7 days
coronectomy procedure
LA
raise flap - generally standard 8 designs
(bone removal)
transection of tooth 3-4mm below the E of the crown into D
elevate/lever crown off without mobilising the roots
- only go 2/3-3/4 through with drill as if cut all way through risk to lingual nerve and artery
pulp left in place untxed
if necessary - further reduction of roots with a rosehead bur to 3-4mm below alveolar crest - not always possible
irrigate socket
flap replaced - some reposition flap leaving socket open, some close flap completely (primary closure with periosteal release if necessary)
HAPOI
follow up of coronectomy
variable
review 1-2wks, 3-6m, 1yr
some review at 2yrs but most discharge back to GDP after 6m/1yr
radiographic review
- 6m or 1yr or both
- after that if symptomatic
- some take an immediate or 1wk post-op radiograph
U8s ext
generally easier to remove can do in practice
but occ v difficult
remove by elevation (Wj, Couplands) +/- forceps (U8s)
support tuberosity w finger and thumb
- if undue resistance to elevation/ext then excessive force can fracture the tuberosity
- use forceps and support to reduce risk
if not possible to get access to a PE U8 - can raise a buccal flap +/- bone removal
peri-op control of bleeding
pressure LA w vasoconstrictor artery forceps diathermy bone wax
post-op control of bleeding
pressure (finger/swab)
LA w vasoconstrictor infiltration in STs, inject into socket or on a swab
diathermy
haemostatic agents - surgicel/kaltostat
sutures
bone wax smeared on socket wall with a blunt instrument
haemostatic forceps/artery clips
Contraindication of coronectomy
◦ Immunosuppressive
◦ Carious tooth
◦ Periodontal involved (mobile)
◦ Career wouldn’t allow regular checkup ( military )
