third molars summary Flashcards
1
Q
eruption
A
- approx 18-24yrs, varies
- may still be present and begin to erupt in elderly/edentulous pt
CO denture rocking/no longer fits
2
Q
crown and root calcification
A
- crown: begins 7-10yo, completed by 18yo
- root: completed btw 18-25yo
3
Q
stats of missing
A
- at least 1 missing in 25% adults
- maxilla
- female
4
Q
guidance and their summary
A
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
5
Q
nerves at risk during SR L8s
A
lingual
IAN
mylohyoid and long buccal - less common and effects less obvious
6
Q
location of lingual n
A
varies
- lies on superior attachment of mylohyoid muscle
- at level of lingual plate in 15-18%
- 0-3.5mm medial to mandible
7
Q
impacted meaning
A
tooth eruption is blocked
- full/ partial functional position
8
Q
incidence of impacted lower third molar
A
around 50%
9
Q
consequence of impaction
A
- caries
- periconronitis
- cyst formaiton
10
Q
U removal indications
A
cheek biting/buccally erupted overeruption traumatising L operculum PE and impacted non-fct pt undergoing GA
11
Q
therapeutic indication of wisdom extraction
A
- caries (8/7)
- pericoronitis
- periodontal disease (7d)
- local bone infection
- Dentigerous cyst
- tumours
- external root resorption of 7/8
12
Q
SIGN vs NICE
A
SIGN - ≥1 episode of infection
NICE >1
13
Q
imaging
A
OPT
(+/- PA)
+/- CBCT (3D relationship to nerve)
14
Q
clinical assessment of M3M
A
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
15
Q
Types of imapction
A
- plus transverse (buccal / lingual)
- aberrant ( in odd place)
16
Q
working space
A
distance between L7 and ascending ramus
17
Q
radiological assessment
A
- 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
18
Q
when to consider when follicle turning to dentigerous cyst?
A
if follicle > 3mm (5mm)size
if >10mm can assume is cyst
19
Q
3 key radiographic signs of M3M - possible increased risk to IAN
A
diversion/deflection of canal
darkening of root where crossed by canal
interruption of tram line / lamina dura of canal
20
Q
8 radiographic signs of possible increased risk to IAN - M3M removal
A
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?
21
Q
juxta apical area
A
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
22
Q
what is the most common orientation of impaction? M3M
A
mesial 40%
23
Q
what is orientation of impaction measured against?
A
the curve of spee
- curve of occlusal plane
- draw lines through long axis of 7 and 8 and compare
24
Q
what are the types of depth of impaction and what does it indicate?
A
- superficial - 8 crown relate to 7crown
- moderate - 8 crown to 7 crown+root
- deep - 8 crown to 7 root
- amount of bone removal required
25
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)
26
pericoronitis definition
- Inflammation around the crown of a **PE** tooth
- need communication with oral cavity
if not visible careful probing 7d for comunication
27
pericoronitis aetiology
- food and debris get trapped under operculum - inflammation/infection
28
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
```
29
which LNs are often raised and palpable in pericoronitis?
SM or upper cervical chain
30
pericoronitis EO swelling
severe cases
| often at angle of mandible and may extend into SM region
31
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)
32
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
```
33
pericoronitis pt instructions
freq warm saline or MW
- teaspoon salt warm water
analgesia
keep fluid levels up and keep eating (soft diet)
34
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
35
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
36
operculectomy
prev
| no longer carried out - often grows back
37
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
38
SDCEP pericoronitis when to send pt to hospital (emergency )
* FOM swelling
* Difficulty breathing
* Trismus
39
SDCEP pericoronitis when to prescribe ABx
- spread of infection (cellulitis / swelling)
- systemic involvement (fever, malaise)
- not resolved by local measures
- symptoms or pus >7 days
40
local measures for pericoronitis
irrigation and debridement (US)
41
1st line ABs for pericoronitis
metronidazole 400mg, 3 days , x3 daily
| avoid alcohol, not if on warfarin
42
2nd line Abs for pericoronitis
amoxicillin 500mg, 3 days, 9 capsules x3 daily
| - hypersensitivity reactions
43
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
44
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
45
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
46
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)
47
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
48
RCS FDS guidelines - main reason for removal
infection
49
RCS FDS guidelines - significant radiological signs of risk to IAN
diversion of IAN canal
darkening of root
interruption of cortical white line
50
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
51
RCS FDS guidelines - common tx
```
referral
clinical review
removal of M3M
ext of U8
coronectomy
```
52
RCS FDS guidelines - less common tx
operculectomy
surgical exposure
presurgical ortho
surgical reimplantation/autotransplantation
53
RCS FDS guidelines - comment on NICE 2000
discouraged prophylactic removal
| - but evidence this isn't always best - delays surgery and damage to 7
54
RCS FDS guidelines - why do coronectomy?
if close to IAN, reduce risk of injury
55
RCS FDS guidelines - coronectomy risks
pain and infection
| potential future need for removal of the roots
56
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
```
57
RCS FDS guidelines - CHX benefits
effective (gel more) - prevents alveolar osteitis
58
RCS FDS guidelines - adverse events of CHX
```
staining
altered taste
burning sensation
hypersensitivity
mucosal lesions
```
59
RCS FDS guidelines - routine radiographic screening of UE8s with no disease or symptoms
not recommended
60
RCS FDS guidelines - clinical review
just reviewing S+S
only xray if clinical S/S of disease
- routine BWs should inc distal of 7
61
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
62
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
63
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
64
loss of tooth/root into:
lingual space
MS
pterygoid space
65
ST damage
puncture/laceration with instruments - gingivae/FOM/palate
burns - from handpiece resting on L lip
crush - papillae/lip
tears - gingivae/palate
66
damage to Rx in 7
if this happens temp Rx placed at time then back for permanent Rx
67
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)
68
rare post-op complications
Osteomyelitis
Osteoradionecrosis
MRONJ
actinomycosis
69
how to explain dry socket to a pt
a slower healing painful socket
1-2wks to settle
come and see us
70
why can altered taste result?
**chorda tympani** arises from facial nerve CNVII , taste buds from ant 2/3 tongue, carries fibres via lingual nerve - CNV3
71
how to explain dysaesthesia to a pt
painful, uncomfortable, unpleasant sensation of L lip, chin, tongue, sometimes neuralgic type pain
72
should you do CBCT?
if concerns of close proximity from radiograph - offer CBCT
| - but would scan change tx?
73
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
```
74
discussing risks to nerves
* can recover up to **18-24m** but after this time not much hope for any further recovery
- 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
75
tx options
* do nothing - monitor
- may need local measures - irrigate, review, pt advice,
risk of recurrence, food trap
* (surgical) extraction
* CBCT
* coronectomy
76
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
77
stages of surgery of M3M ext
* anaesthesia
* access
* **bone removal** and **tooth division** as necessary
* debridement
* suture
* haemostasis
* POIs
* post-op medication
78
access
buccal mucoperiosteal flap
| +/- lingual flap (debate)
79
ST retraction/reflection
access
| protect STs
80
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)
81
what facilitates retraction?
flap design
82
where should you commence flap-raising?
commence flap raising at base of relieving incision (already gaping/bone visible)
83
instruments for ST retraction
minnesota retractor
rake retractor
howarth's periosteal elevator
84
instruments for ST reflection
Ash periosteal elevator
Howarth's periosteal elevator
Curved Warwick james elevator
Mitchell trimmer
85
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**
86
why raise flap?
access to surgical site
improve visibility, visualise application point
facilitate bone removal
87
flap considerations
important structures (esp for relieving incision) e.g. nerves
blood supply and healing
aesthetics
ease of suturing post-op
88
flaps and papillae
need to either include or exclude papillae
89
atraumatic/passive retraction
rest firmly on bone
| aware of adjacent structures e.g. mental n
90
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
91
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
92
envelope flap
| 1-sided 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**
93
what blade to cut a flap?
number 15
94
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
95
crevicular incision
hold scalpel in LA of tooth
blade kept immediately against tooth surface
96
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
97
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
* plenty **irrigation** (avoid bony necrosis + visibility)
* protect STs
98
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
99
aim of bone removal
allow correct application of elevators on M and B of tooth, better visual access
100
when would you section a tooth?
if tooth removal still not possible with elevators +/- forceps and adequate bone removal
101
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 **twist elevator to snap and Lever off**
102
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
103
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**
104
forceps commonly used for L
molars, **cowhorns**, universal, roots
105
forceps commonly used for U
8s, molars, universal, roots, **Bayonet**
106
types of debridement
physical
irrigation
suction
107
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
108
irrigation debridement
sterile saline into socket and under flap
| must irrigate below flap before you reposition it
109
suction debridement
aspirate under flap to remove debris
| check socket for retained apices etc
110
2 methods of suturing
flap closure
anatomical repositioning
111
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
112
anatomical repositioning
most prefer to return flap to its original position, leaving a socket
113
aims of suturing
reposition tissues
cover bone
**prevent wound breakdown**
achieve **haemostasis**
encourage healing by primary intention
114
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**
115
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
- 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
116
indications for coronectomy
high risk of IAN injury
vital M3M
healthy non-IC pt
access to care for (and understanding of) related coronectomy risks
117
Tara Renton paper 2005
Randomised controlled trials
shows much lower risk to IAN with coronectomy compared to SR
118
principles of coronectomy
* **remove all enamel**
* **tooth roots** must **not be mobile** after decoronation
* **smooth finish** to decoronated tooth and surrounding bone
119
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
120
aim of coronectomy
reduce risk of IAN damage
121
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
122
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
123
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
124
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 buccal flap** +/- bone removal
125
peri-op control of bleeding
pressure
LA w vasoconstrictor
artery forceps
**diathermy**
**bone wax**
126
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
127
Contraindication of coronectomy
◦ Immunosuppressive
◦ Carious tooth
◦ Periodontal involved (mobile)
◦ Career wouldn’t allow regular checkup ( military )
