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MODULE 6 > OS - third molars > Flashcards

OS - third molars Flashcards

1
Q

list the requirements for surgical removal of teeth

A
  • when you cannot remove/ xLA a tooth conventionally
  • gross caries
  • complex root morphology
  • retained roots below bone
  • impacted teeth
  • displaced teeth
  • ectopic teeth
  • pathology (cysts, external root resorption)
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2
Q

why may you have to surgically remove a tooth with gross caries?

A

unable to use forceps
no application point for elevators

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3
Q

why may you have to surgically remove retained roots that are below alveolar bone level?

A

no application point for elevators

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4
Q

in general terms, why does impaction occur?

A

prevention of complete eruption into a normal functional position due to lack of space or development in an abnormal position.

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5
Q

why may impaction predispose pathological changes?

A

while the tooth germ is forming there is a pathological change that affects the tooth - can involve soft tissues or hard and soft tissues.

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6
Q

aetiology of ectopic teeth?

A

malpositioned due to congenital factors

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7
Q

aetiology of displaced teeth?

A

malpositioned due to presence of pathology i.e., a cyst

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8
Q

describe completely unerupted teeth?

A

entirely covered by soft tissue and also partially/ totally covered in alveolar bone

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9
Q

describe ankylosed teeth?

A

fused with alveolar bone, rare with 8s, occurs after middle age

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10
Q

what is the cause of impacted teeth?

A

due to lack of space in the arch as a consequence of evolutionary changes and lack of an abrasive diet

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11
Q

list in order the commonest affected impacted teeth?

A

mandibular third molars
maxillary canines
mandibular premolars/canines
maxillary incisors
maxillary third molars

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12
Q

at what age do mandibular third molars usually emerge?

A

18-24 years

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13
Q

what is the prevalence of mandibular third molars to fail to develop?

A

1:4 adults

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14
Q

what is the prevalence of impacted third mandibular molars?

A

72%

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15
Q

what is is the decision for xLA mandibular third molars?

A

decision to remove based on balance of risk of observation against removal before overt disease develops

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16
Q

what guidelines are followed for removal of third molars?

A

National Institute for Clinical Excellence (NICE) 2000

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17
Q

list the indications for removal of mandibular third molars

A

pericoronitis
unrestorable caries
cellulitis/ osteomyelitis
periodontal disease
ortho reasons
prophylactic removal in medically compromised pts
obscure pain
disease of follicle
orthognathic surgery
transplant donor

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18
Q

what happens to teeth in the line of a fracture?

A

non vital

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19
Q

what are the relative contraindications for removal of third molars?

A

asymptomatic teeth
non-compliant patients
overt nerve involvement

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20
Q

what is pericoronitis?

A

inflammation of the tissues around the crown of any partially erupted/ impacted tooth

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21
Q

how many episodes of pericoronitis makes it an indication for xLA?

A

2 or more

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22
Q

list the features of pericoronitis?

A

trismus, pain, dysphagia, malaise, bad taste
signs of inflammation of the pericoronal tissues, with pus under operculum
halitosis, food packing
can progress with systemic symptoms and spread to adjacent tissue spaces

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23
Q

what is commonly performed in America to solve pericoronitis?

A

operculectomy

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24
Q

why do we not routinely practise operculectomy’s?

A

operculum will grow back

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25
Q

treatment options for a tooth in whose soft tissues have been traumatised from upper molar?

A

xLA upper 8
grind upper 8 cusps down

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26
Q

treatment options for pericoronitis?

A

local measures
- irrigation, OHI (small headed tooth brush/ water pick)
- remove trauma i.e., xLA upper 8 or grind down cusps

general measures
- analgesics, antibiotics if systemically unwell/ immunocompromised
- admission in severe airway threatening cases

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27
Q

list the microbes associated with pericoronitis?

A

predominantly anaerobic
strep, actinomyces, propionibacterium, a-beta-lactamase producing prevotella, bacteroides, fusobacterium, capnocytophaga and staph

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28
Q

what anaerobes are related to the increased incidence of second and third molar perio pockets deepening over 2 years?

A

prevotella intermedia
campylobacter

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29
Q

when can antibiotics be prescribed for pericoronitis?

A

when surgical removal of the cause or drainage of the infection under LA is impossible e.g., trismus, pt compliance

evidence of a systemic spreading infection needing urgent referral for hospitalisation

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30
Q

what are conservative treatment choices for removal of mandibular third molars?

A

monitor with radiographs

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31
Q

what treatment option is available for mandibular third molars if there is risk of damaging the inferior dental canal?

A

coronectomy

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32
Q

what may happen to existing TMJ pain after xLA?

A

worsens

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33
Q

what is the 7 at risk of with xLA of the 8 where there are perio pockets?

A

distal root exposure - sensitive

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34
Q

what radiographs are generally required to assess mandibular wisdom teeth?

A

OPG
PA sometimes - shows root apices and relation to IDC

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35
Q

what do radiographs assess with mandibular third molars?

A

all the tooth and adjacent structures including bone, tooth morphology and number and shape of the roots, hypercemetosis
depth of bone around tooth
follilcular pattern
external root resorption
caries in distal of 7

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36
Q

what classifications are made from radiograph assessment?

A

relation
angulation to the adjacent teeth
proximity to the IDNerve

37
Q

when radiographically classifying mandibular third molars, what is relation?

A

relation to the 7, crown, ACJ or roots

38
Q

when radiographically classifying mandibular third molars, what types of angulations can you get?

A

vertical
mesioangular
distoangular
horizontal
transverse
aberrant

39
Q

what do Winter’s assess?

A

how much bone will be removed

40
Q

what are the 3 winters lines?

A

occlusal plane line
bone margins
vertical line that joins

41
Q

what is the most common angle of impaction of 3rd molars?

A

mesial

42
Q

list 6 radiographic signs of a close relationship between the lower third molar and the IDC

A
  1. diversion of IDC
  2. darkening of root as it is crossed by the IDC
  3. loss of lamina dura of IDC
  4. narrowing of IDC
  5. deflection of roots of lower third molar as they approach the IDC
  6. juxta apical area
43
Q

what is a juxta apical area?

A

free floating apex on one side of the IDC

44
Q

what is indicated when the IDC passes through the roots of a tooth but both lines are interrupted?

A

superimposition

45
Q

what is indicated when there is loss of IDC lamina dura as it passes through the roots of a tooth?

A

close relationship - can cause bruising to canal which will give pt an altered sensation to the lip

46
Q

what is indicated when the IDC lamina dura is lost and there is a change in radiolucency of the roots?

A

suggests less mineralised tissue - canal is sititng in the groove of roots or perforates them

47
Q

what are the risks with a narrowed IDC?

A

indicates a close relationship to the roots - short term complication
however, if roots are rotated on removal - long term complication

48
Q

where do the vast majority of IDC sit?

A

on the lingual aspect of the third molars (70%)

49
Q

what must you do with a pt if they IDC is interrupted when the third molar is removed and you can see the contents of the bundle left in the socket?

A

review and document sensation for 18 months
if still numb after 18 months, unlikely to improve

50
Q

what is the prevalence of lower lip altered sensation in short and long term post op?

A

short term - 5%
long term - less than 15%

51
Q

what is the prevalence of tongue altered sensation short term and long term post op?

A

short term - 10%
long term - less than 1%
taste can be affected too

52
Q

what is an alternative surgery performed if the risk is high to the IDN?

A

coronectomy - remove the crown and leave roots in place

53
Q

when performing a coronectomy, you realise the roots are mobile, what do you do?

A

remove them

54
Q

what are the risks following a coronectomy?

A

root removal unavoidable
infection
migration of roots

55
Q

what should happen to the socket after a coronectomy?

A

socket should fill with bone, roots become intraalveolar

56
Q

describe anaesthesia after LA

A

numbness

57
Q

describe paraesthesia after LA

A

tingling when LA wearing off

58
Q

describe hypoaesthesia after LA

A

reduced sensation

59
Q

describe disaesthesia after LA

A

pain

60
Q

what are the preoperative warnings you tell the pt prior to surgery of 3M?

A

pain
swelling
bruising
possible hypoaesthesia of lip/tongue
trismus
diet advice

1 week

61
Q

what must pt be warned of prior to surgery of 3M

A

post op complications greater than 5% incidence

62
Q

what are the 5 points planned from a radiograph for surgical xLA of a mandibular 3rd molar?

A

path of eruption
extrinsic/ intrinsic obstacles to removal
required bone removal
point of application
flap design

63
Q

what are extrinsic obstacles to removal of mandibular third molars

A

adjacent teeth
IDN

64
Q

what are intrinsic obstacles to removal of mandibular third molars?

A

converge, diverge, bulbous, fused, ankylosed roots

65
Q

describe a triangular flap

A

distal relieving incision up the ascending ramus, around crown of 3M, including papilla between 3M and 2M
mesial relieving incision
(3 sided)

66
Q

how does an envelope flap differ to a triangular flap?

A

no mesial relieving incision in envelop flap

67
Q

during a surgical removal of 3M what elevation technique and elevators are used?

A

atraumatic elevation using periosteal elevators
- mitchells trimmer
- warwick james elevator
- molt no.9 periosteal elevator
- Howarth’s periosteal elevator

68
Q

during surgical removal of 3M, what is used to raise lingual flap?

A

Howarths/Mitchells/Molt
*not for novice operators

69
Q

describe an envelope flap

A

distal relieving incision
peri-coronal incision round 3M and 2M

70
Q

how are burs used for bone removal?

A

round bur creates narrow gutter mesiobuccaly
fissure bur deepens gutter

71
Q

units of a surgical handpiece?

A

20000-40000 units per min

72
Q

how can the crown of a 3M be divided during surgical removal?

A

horizontally or axially
*ALL horizontally impacted teeth must be sectioned

73
Q

what is important when planning flap design after surgical xLA 3M?

A

flap must rest over bone to avoid wound breakdown

74
Q

what is the most important suture?

A

one placed from the buccal tissue to the lingual tissue immediately distal to the second molar - encourages good periodontal health

75
Q

what material is used for suturing?

A

3/0 vicryl rapide - it is resorbable

76
Q

post op regime for surgical xLA?

A

analgesics
soft diet
topical ice pack
HSMW day after
suture removal at 1 week if not resorbed
follow up for immunocompromised or difficult cases

77
Q

what analgesics are recommended post op?

A

paracetamol
cocodamol 5 days
NSAIDs

78
Q

when would you give a pt antibiotics?

A

immunocompromised
pt returns with infection

79
Q

how would you tell a pt to use ice packs?

A

15 mins on 15 mins off day of tx

80
Q

when is post op bruising common?

A

elderly as tissue loses elasticity
gravity can make bleeding track down neck

81
Q

list complications of surgery xLA 3M?

A

haemorrhage - primary/ secondary
loose teeth/ damage to adjacent teeth/ restorations
fractured mandible
dry socket
sensory deficit
general xLA complications

82
Q

how are maxillary third molars commonly impacted?

A

MA
V

83
Q

why are surgicals of maxillary third molars less complicated?

A

thin cortical bone

84
Q

how may access be difficult to maxillary third molars?

A

malar buttress
buccal position

85
Q

when would you merit removal of upper 8’s?

A

GA for removal of symptomatic lower 8s

86
Q

complications of a buccal placed maxillary third molar?

A

ulceration of buccal tissue
painful mouth opening

87
Q

explain surgical removal of unerupted maxillary 3M?

A

raise buccal flap
thin friable bone removed with couplands
elevate
back and buccal

88
Q

why do we avoid excessive upwards force with removal of maxillary 3Ms?

A

possible displacement into antrum

89
Q

how many sutures are used after removal of maxillary 3M?

A

1

MODULE 6 (69 decks)

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