Third Molars 2 Flashcards
3 parts of wisdom tooth assessment
history
clinical
radiographic
Also eval pt ability to the consequences of each tx option
history aspects for 3rd molar assessment
General Appearance
* Swelling, asymmetry, anxiety, difficulty swallowing/speaking
Presenting complaint eg recurrent pericoronitis
History of Presenting Complaint –how long, how many episodes, how often, severity, requirement for antibiotics?
Medical History – systemic enquiry, Medications, Allergies, Previous hospitalisations inc surgery
Dental History – history of extractions, dental anxiety, dental experience, regular oral hygiene
Social History – smoking, alcohol, occupation, carer, support
extra oral clinical assessment for 3rd molars
TMJ’s – assess if any TMD, similar pain as pericoronitis
Limited mouth opening (surgical access)
Lymphadenopathy – enlarged, tender
Facial asymmetry
Muscles of Mastication
intra oral clinical assessment for 3rd molars
Soft Tissue examination
Dentition
M2M – prognosis, working space – distance from M2M to ascending ramus of mandible
Eruption and status of the M3Ms – any communication, how erupted (1 cusp, 2/3 occlusal surface), operculum
Condition of the remaining dentition
Occlusion
Oral hygiene
Caries status
Periodontal status
radiographic assessment for 3rd molars
when
only if surgical intervention is being considered
use OPT
OPT of 3rd molars to determine
Presence or absence of disease (in 3M or elsewhere)
Anatomy of 3M (crown size, shape, condition, root formation)
* Crown root ratio – large crown, small roots = harder to extract, not enough access to get tooth to pop out of socket (need surgical)
Depth of impaction
Orientation of impaction
Working distance
Follicular width
Periodontal status
The relationship or proximity of upper third molars to the maxillary antrum (sinus) and of lower third molars to the inferior dental canal (bony cavity)
Any other assoc pathology/abnormalities
depth of impaction options
- Superficial – crown of 8 is sitting at same heigh at adj 7
- Moderate – crown of 8 is sitting somewhere between roots and crown of 7
- Deeply – crown of 8 is sitting at root height of adj 7
orientation of impaction options
- Vertical – up and down
- Mesial
- Distally
- Horizontal
- Transverse
3rd molar working distance
distal of lower 7 to ramus of mandible
follicular width is
Tissue that surrounds the crown on developing tooth
* Usually lost on eruption
Unerupted tooth – this will appear as a radiolucency, if it gets large some evidence suggest indicative of pathology so keep an eye on them (2.5mm+)
OPT what to assess for IDB canal
- interruption of the white lines/lamina dura of the canal
- darkening of the root where crossed by the canal
- diversion/deflection of the inferior dental canal
- deflection of root
- narrowing of inferior dental canal
- Narrowing of the root
- Dark and bifid root
- juxta apical area?
3 signs that have been shown to have significantly increased risk fo nerve injury during 3rd molar surgery
diversion of the inferior dental canal
darkening of the root where crossed by the canal
interruption of the white lines of the canal
what is this
diversion/deflection of the inferior dental canal
IDB canal shapes round the outline of the 8 apices
what is this
darkening of the root where crossed by the canal
Dark band is IDB canal - apices at same level as IDB canal
what is this
interruption of the white lines/lamina dura of the canal
can usually see both upper and lower borders of IDB canal
but either upper or upper and lower borders of tramline lost
what is this
deflection of roots
IDB canal caused curvey roots
what is this
narrowing of inferior dental canal
narrower as it spasses apices of 8
what is this
narrowing of roots of 8
what is this
dark and bifid roots
roots splits or divides over canal
what is this
Well circumscribed radiolucent lateral to root of molar not just at apex
Well defined area, can be corticated
Lamina dura still in tact
Appearance is not pathological – must check (tooth vitality and infection status)
further imaging for 8s when
“Where conventional imaging has shown a close relationship between the third molar and the inferior dental canal, cone beam computed tomography (CBCT) may be of benefit. “
further imaging for 8s when
“Where conventional imaging has shown a close relationship between the third molar and the inferior dental canal, cone beam computed tomography (CBCT) may be of benefit. “
if suspect close relationship, consider CBCT (IDB canal and M3M)
if CBCT not available, CT can be used but limited field of view
radiological assessment used to confirm what
angulation
- Vertical – around 30 - 38% of impacted lower 8’s
- Mesial – around 40%
- Distal – around 6 - 15%
- Horizontal – around 3 - 15%
- Transverse (less common) crown buccally placed and roots lingually placed or vice versa
- or aberrant – not where expect to find e.g midway up ramus of mandible or at lower border of mandible
radiological angulation of 8s measured against
curve of Spee
natural curve following the cusps of a natural dentition
how to assess impaction
ne through 8 and 7, where 8 lies in relation to 7
impaction of 8s?
LR8 - mesially impacted
LL8 - horizontally impacted
impaction of 8s?
LR8 - horizontally impacted
LL8 - distoangular impacted
hardest impaction to extract?
distally impacted 8s
need to remove distal bone
impaction of 8s?
LR8 - true vertical impaction
LL8 - distal impaction
impaction of 8?
transverse impaction
impaction of 8?
LL8 aberrant position
depth of impaction indicates
amount of bone removal required
how to measure depth of impaction
measure crown 8 against adj 7 crown
superficial
moderate
deep
superficial impaction
crown of 8 related to crown of 7
moderate impaction
crown of 8 related to crown and root of 7
deep impaction
crown of 8 related to root of 7
impaction of 8s depth?
LL8 - superifical distoangular
LR8 - moderate mesioangular
impaction of 8 depth?
superficial mesial LL8
impaction of 8 depth?
moderate vertical
what other radiographic finding would need to warm pt of here?(not 8)
LR7 – overhang amalgam
risk of restoration damage due to proximity, temporise tooth and work on later
