Impacted Third Molars Flashcards
Around what age do third molars generally erupt?
18-24 yrs
What percentage of adults do not have at least 1 third molar?
25%
Which nerves are at risk during surgical removal of third molars?
- Inferior Alveolar Nerve
- Lingual Nerve
- Long Buccal Nerve
- Mylohyoid Nerve
What is the nerve supply for the tongue?
ANT 2/3
- Taste (sp sensory) = chorda tympanii branch of facial nerve (CN VII)
- Sensation = lingual branch of mandibular (V3) trigeminal nerve (CN V)
POST 1/3
- Taste and sensation = glossopharyngeal nerve (CN IX)
Why should the distal relieving incision be angled buccally around the retromolar pad?
The lingual nerve can run quite high, distal relieving; avoids damage to this nerve
What is the definition of an ‘unerupted tooth’?
- A tooth that lies within bone of the jaw
- Completely covered by soft tissues (partially/ completely covered by bone)
What is the definition of a ‘partially erupted tooth’?
- A tooth that may have failed to erupt fully
- Tooth partially in communication with oral cavity
What is the definition of an ‘impacted tooth’?
- A tooth which is prevented from erupting completely
- May be due to = lack of space, obstruction by another tooth/ bone, abnormal eruption path
Name a guideline set in place for removal of wisdom teeth
- NICE
- SIGN (withdrawn but principles still follow)
When is removal of wisdom teeth NOT advised?
- Tooth judged to erupt successfully with functioning role
- MH renders unacceptable risk; risk exceed benefit
- Deeply impacted with no hx or evidence of related local/ systemic pathology
- Risk of surgical complication unacceptably high (incl # of mand)
- Asymptomatic contralateral tooth not adivsed to be taken out along with planned wisdom tooth
When is removable of wisdom teeth ADVISED?
- Significant infection (associated with tooth)
- Risk factors and lifestyle prevents ready access to dental care
- MH renders risk of retention unacceptable (chemo/radio)
- Risk of retention outweighs further GA
What are STRONG indications for removal of wisdom teeth?
- At least 1 episode of infection (abscess, pericoronitis, cellulitis) or untreatable pulp/ apical pathology
- Caries and untreatable
- Perio disease due to 8+7
- Dentigerous cyst/ other related pathology
- External resorption caused by 8
OTHER
- Autogenous transpant
- # of mandible in that region, resection of tumour
- Prophylactic removal (of likely to erupt 8) in certain medical conditions
- Atypical pain (rule out TMD!)
- Food trapping
What should be considered in the patient’s medical history before removal of wisdom teeth?
- Medical conditions contraindicating removal
- Medications (bleeding etc)
- Allergies
What is INR?
International normalised ratio
- NORMAL = 0.8 - 1.2
- Warfarin target = 2-3
What is the safe limit of INR for tooth extraction?
3.5 or less
What should be assessed in a CLINICAL examination for the removal of wisdom teeth?
- Eruption status
- Local infection (and regional lymph)
- Caries/ resorption
- Perio status
- Occlusal relaitonship
- TMJ function (sometimes TMD manifest as upper 8 pain)
- Degree of access
What should be assessed in a RADIOLOGICAL examination for the removal of wisdom teeth?
- Orientation of tooth
- Relationship to IAN canal
- Crown size and condition
- Tooth and root morphology
- Alveolar bone levels
- Perio status incl 7
- Associated pathology
What are the radiological signs that there is an increased risk of nerve damage upon removal of the tooth?
- Diversion/ narrowing of IAN canal
- Darkening of roots where crossed by canal
- Interruption of white lines of canal
–> SECOND XR image required (usually CBCT)
What are the orientations possible?
- Vertical 35%
- Mesial 40%
- Distal 10%
- Horizontal 8%
- Transverse/ aberrant
Describe possible depths in relation to the adjacent tooth of 8s
- Superficial = crown of 8 related to crown of 7
- Moderate = crown of 8 related to crown AND root of 7
- Deep = crown of 8 related to roots of 7
What is ‘pericorontitis’?
Inflammation of soft tissues around crown of tooth occurring where there is a communication between tooth and oral cavity (bacterial involvement)
What are the signs and symptoms of pericorinitis?
LOCAL
- Pain & swelling
- Bad taste + smell
- Pus
- Occlusal trauma to operculum
SYSTEMIC
- Trismus
- Dysphagia
- Pyrexia
- Malaise
- Regional lymphadenopathy
Where are the possible regions of swelling associated with an infected 8?
- Angle of the mandible
- Buccal space
- Sublingual space (Ludwig’s angina)
What is the management of an infected 8?
- Incision if abscess localised
- Irrigation with warm saline/ CHX or astringent/ antiseptic below operculum
- -> Advise pt mw
- Analgesia advice
- If trauma to opererculum, compensate opposing 8
- Systemic involvement –> AB (metronidazole)
–> DO NOT EXTR UNTIL ACUTE EP RESOLVED
- If severe –> Max fac or A&E!
What are the treatment options for removal of wisdom teeth?
ASYMPTOMATIC
- Monitor
SYMPTOMATIC
- XLA/ SR (gold standard)
- XLA of opposing 8
- If close relationship with canal –> further imaging –> coronectomy
What are some post-op complications?
- Pain
- Swelling
- Bruising
- Trismus
- Numbness/ tingling (dysaesthesia)
- Bleeding
- Infection
- Dry socket
What are the percentages of permanent and temporary nerve damage?
IAN
- TEMPORARY = 10-30%
- PERMANENT = <1%
Lingual
- TEMPORARY = 10-20%
- PERMANENT = <1%
