Oral Surgery Flashcards
What are the indications for 3rd molar extraction?
7
Recurrent Pericoronitis
Periodontal disease
Root resorption of 2nd molar
Gross dental caries
Odontogenic cyst/tumour
Supra-erupted (maxillary) - ST damage
Non-functional
Definition of a dentigerous cyst
3
RL surrounding crown of erupting tooth >3mm
Attaches to CEJ of tooth
Exclusive to permanent dentition
Where does a dentigerous cyst originate from?
Epithelium of follicle of developing tooth
Dentigerous cyst differential diagnosis
3
Unicystic ameloblastoma
ondotogenic keratocyst
hyperplastic dental follicle
Name 4 secondary facial spaces
Pterygomandibular
temporal
retropharyngeal
parotid
3 points
How do retained 8s affect periodontal status
key points from White paper - 2007
visible 3rd molars = higher incidence of periodontitis of 8 and adj. teeth
These teeth are only partially responsive to periodontal therapy
Periodontal defects increase with age around retained 8s
True or False - morbidity associated with surgical removal of 8s increases over age of 25
True
List 4 patient factors that should be assessed and why
Size - access
Age - elasticity of bone
Presence of infection - anaesthesia, trismus
anxiety - ability to tolerate procedure
List 5 factors that should be assessed in I/O exam and why
distance to 2nd molar - likelihood of impaction under ramal bone
Crowding - access
Soft tissue around 8 - periocoronitis
Caries - likelihood of coronal fracture during exo
Thickness of bone adj to external oblique ridge
4 categories - depth/angle, roots, anatomy around tooth, position. 11 pt
List the elements of a difficult surgical case
Distoangular
Class III ramus
Class c depth
Long thin roots
divergent/curved roots
narrow PDL
thin follicle
dense inelastic bone
contact with 2nd molar
close to IAN
complete bone impaction
List the 4 classifications according to Winter
Mesioangular
Distoangular
Verical
Horizontal
Describe class A depth according to Pell and Gregory
Occ plane of 8 = occ plane of 7
Describe class B depth according to P+G
occ plane of 8 is between occ plane and CEJ of 7
Describe class C depth according to P+G
occ plane of 8 is below CEJ of 7
Describe class 1 ramal position according to P + G
8 has sufficient room anterior to border of ramus to erupt
Describe class 2 ramal position according to P + G
1/2 of 8 is impacted in ramal bone
Describe class 3 ramal position according to P + G
8 is completely impacted in ramal bone
What are the 3 key markers for IAN involvement with 3rd molar
- Darkening of canal as it passes over tooth structure
- Deviation of canal below tooth root
- Loss of upper border of canal
What are the 4 types of flaps
- distal relieving incision
- envelope flap
- buccal extension flap
- triangular flap
What is the potential issue with raising a buccal flap?
Can cause delayed periodontal healing and increased CAL
What is a pro and con of an envelope flap design?
Pro: decrease change of haematoma + post op bleeding (conservative)
Con: Limited access for deep impaction
Why is bone removed?
to allow for better access and point of application for instruments
How much bone should be removed?
Enough to expose entire crown to level of furcation
What are the 5 stages of a surgical extraction?
- raise flap
- remove bone
- section tooth
- wound toilet
- closure
What are the 3 types of nerve injury and describe each
- Neuropraxia - blunt or compression injury = loss of function for hours or. months
- Axontomesis: loss of continuity of axon or myelin sheath. Weeks
- Neurotmesis: severe contusion, laceration or stretch. Loss of connective tissue. Complete loss of function. Often permanent
What are the 5 patterns of sensory loss?
Hyperaesthesia - heightened sense
Hypoaesthesia - decreased sensitivity
Paraesthesia - abnormal sensation
Dysthesia - abnormal unpleasant sensation
Anaesthesia - lack of sensation
What is the prevalence of permanent IAN injury?
<1%
What is the classification for maxillary wisdom teeth?
I - fully/partially erupted
II - wisdom tooth above apices of 7
III - wisdom tooth below apices of 7
Why is sectioning often not necessary for maxillary 8s?
alveolus is softer than mandible
What is a considerable risk when extracting a class III maxillary molar?
Displacement of tooth into sinus or infratemporal space.
