Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

My BDS4 > OS - 3rd Molars > Flashcards

OS - 3rd Molars Flashcards

1
Q

Between what ages do 3rd molars erupt?

A

18-24y/o

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When does radiograph crown calcification of upper and lower 3rd molars start and when is it finished?

A

upper = 7-9y
lower = 8-10y

completed by age 18y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When does radiographic root calcification of 3rd molars finish?

A

18-25y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does impacted mean?

A

Where tooth eruption is blocked
- Tooth can be unerupted, PE or fully erupted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the most common cause of 3rd molars failing to erupt?

A

impaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What can 3rd molars impact against? (3)

A
  • adjacent tooth
  • alveolar bone
  • surrounding mucosal soft tissue
    (combination of these factors)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the complications of impacted 3rd molars? (3)

A
  • caries
  • pericoronitis
  • cyst formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What nerves are at risk during 3rd molar surgery? (4) - which 2 are the most commonly affected?

A
  • Inferior Alveolar Nerve
  • Lingual Nerve
  • Nerve to Mylohyoid – less commonly affected and effects are less obvious
  • Long Buccal Nerve - less commonly affected and effects are less obvious
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What kind of nerve is the inferior alveolar nerve?

A

peripheral sensory nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What nerve does the IAN nerve branch from?

A

mandibular div of trigeminal nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the IAN supply? (2)

A

sensation to the;
All the pulp of mandibular teeth (on that side)
Mucosa/skin of the lower lip and chin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What nerve does the lingual nerve branch from?

A

the mandibular div of the trigeminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the lingual nerve supply? (2)

A

Anterior 2/3rds of dorsal and ventral mucosa of the tongue

Another branch supplies the lingual gingivae and the floor of mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the THERAPEUTIC indications for M3M extractions? (4)

A
  • Infection: from caries, pericoronitis, periodontal disease or local bone infection (most common)
  • Cysts - Most common = in mandible (10x)
  • Tumours
  • External resorption of 7 or 8
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are other indications for M3M (not therapeutic) extractions? (7)

A
  • Surgical indications ie within the surgical field (orthognathic, fractured mandible, in resection of diseased tissue surgeries)
  • If tooth has a high risk of disease e.g. in horizontal/mesioangular impaction
  • Medical indications eg. awaiting cardiac surgery (must be dentally fit), immunosuppressed, starting bisphosphonates or to prevent osteonecrosis
  • Accessibility to the dentist e.g. submariners, aid workers etc
  • Patient age: complications and recovery time increase with age
  • Autotransplantation: tooth relocated to another site i.e. 1st molar site
  • General Anesthetic: radical tx to prevent a further GA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is pericoronitits?

A

Inflammation around the crown of a partially erupted tooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What causes pericoronitis?

A

Food & debris gets trapped under the operculum resulting in inflammation or infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Does general health have an influence on the risk of developing pericoronitis?

A

not related to incidence except when px has an upper respiratory tract infection = increased incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What microbes are commonly associated with pericoronitis?

A

Anaerobic microbes:
Streptococci , Actinomyces, Propionibacterium, a beta-lactamase producing Prevotella, Bacteroides, Fusobacterium, Capnocytophaga and Staphylococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

At what age does pericoronitis usually occur?

A

20-40y/o

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

List the predisposing factors to developing pericoronitis (7)

A
  • Partial eruption and vertical or distoangular impaction
  • Opposing maxillary M3M or M2M causing mechanical trauma contributing to recurrent infection
  • Upper respiratory tract infections and stress and fatigue
  • Poor oral hygiene
  • Insufficient space between the ascending ramus of the lower jaw and the distal aspect of the M2M (L7)
  • White race
  • A full dentition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does pericoronitis look like clinically? (not symotoms)

A

tooth is normally partially erupted and visible – occasionally there may be very little evidence of the communication and careful probing distal to the second molar is required to show that there is a small communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the signs and symptoms of pericoronitis? (10)

A
  • Pain – variable - starts mild and progresses, described as throbbing.
  • Swelling – Intra or extraoral at angle of the mandible
  • Bad taste
  • Pus discharge
  • Occlusal trauma to operculum from opposing cusps = Ulceration of operculum
  • Evidence of cheek biting
  • Foetor oris
  • Limited mouth opening
  • Dysphagia – when infection reaches parapharyngeal space/tonsils

Systemic symptoms:
Pyrexia (fever), Malaise, Regional lymphadenopathy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do we treat pericoronitis? (5)

A

Usually transient and self limiting, however;

+/- local anaesthetic
- Incision of localised pericoronal abscess if required
- Irrigation with warm saline or chlorhexidine mouthwash under the operculum
- Extraction of upper third molar if traumatising the operculum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What post-op instructions do we give to those with pericoronitis? (3)

A
  • Patient instructed on frequent warm saline or chlorhexidine mouthwashes at home
  • Advice regarding analgesia
  • Instruct patient to keep fluid levels up and keep eating (soft/liquid diet if necessary)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

When are antibiotics used for pericoronitis? (6)

A

more severe localised pericoronitis

or
px systemically unwell (fever etc)
extra-oral swelling
severe trismus
px immunocompromised e.g. diabetic
if there is persistent infection after local measures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why must we thoroughly assess the TMJ before 3rd molar treatment?

A

To rule out TMD - cause similar pain symptoms to pericoronitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What must we assess intra-orally in a patient with 3rd molar symptoms? (10)

A
  • Soft Tissue examination (lips, cheeks, tongue, FOM, pharynx, palate)
  • General dentition
  • Lower 7’s: condition & prognosis
  • Distance between M7 and start of the ascending ramus = shows working space (to remove the 3rd molar)
  • Eruption status of the M3Ms; fully, PE, unerupted (probe to assess communication) and describe the status of PE.
  • Occlusion
  • Operculum: is it inflamed, is there pus, is it a food trap, is there caries?
  • Oral hygiene
  • Caries status
  • Periodontal status
29
Q

When is an OPT radiograph justified to assess M3Ms? (2)

A

If a patient is symptomatic
If surgical intervention is indicated

30
Q

What is involved in a radiographic report for 3rd molars? (9)

A
  • Presence or absence of disease (in 3M or elsewhere)
  • Anatomy of 3M (crown size, shape, condition, root formation – apical hooks or large curves)
    Assess crown to root ratio
  • Depth of impaction
  • Orientation of impaction (vertical, horizontal, transverse, M or D)
  • Working distance (distal of lower 7 to ramus of mandible)
  • Follicular width (appears as radiolucency on an x-ray) : can become a cyst
  • Periodontal status
  • The relationship or proximity of upper third molars to the maxillary antrum and of lower third molars to the inferior dental canal
  • Any other pathology/abnoramlity
31
Q

What size of follicles are most likely to become cystic?

A

> 2.5-3mm

  • Ignore and go for 4mm
32
Q

How do we describe/classify M3M’s in relation to the IDC (1)? List (7)

A

Use Rood and shehab classifications

Narrowing of the canal
Narrowing of the root
Diversion of the canal
Deflection of the root
Dark and bifid root
Interruption of the lamina dura of the canal
Darkening of the root where crossed by the canal
(Juxta apical area)

33
Q

Describe a juxta apical area in relation to M3Ms. (5)

A

well circumscribed radiolucent region lateral to the root
Well defined and well corticated
Near the apex or lateral to the root
Lamina dura intact
Not pathological but you must confirm this is present

34
Q

What 3 radiological signs (Rood and shehab) are associated with a significant increase in risk to the IDN?

A
  1. diversion of the inferior dental canal
  2. darkening of the root where crossed by the canal
  3. interruption of the white lines of the canal
35
Q

How do we measure angulation of M3M?

A

measure the long access of the 8 against the long axis of the 7 and the curve of spee.

36
Q

List the various angulations of an M3M. (6)

A
  • Vertical – 2nd common
  • Mesial – most common
  • Distal (refer as hard to remove)
  • Horizontal
  • Transverse – crown buccally placed and roots lingually placed (or vice versa)
  • Aberrant - tooth situated in an unusual/odd place (midway up the ramus or lower border of the mandible)
37
Q

How do we assess the depth of M3Ms?

A

Assess the relationship between the crown of the 3rd molar to the adjacnt crown/roots of the 2nd molar

38
Q

List the 3 depths of M3Ms and describe.

A
  • Superficial – crown of the 8 is at the same height as the crown of the 7
  • Moderate – crown of 8 related to crown and root of 7 (in between the superficial and deep)
  • Deep – crown of 8 is at the same level as the roots of the 7
39
Q

When is further imaging of M3Ms required? What imaging would we use?

A

Where conventional imaging has shown a close relationship between the third molar and the inferior dental canal.
- CBCT or CT is CBCT not available

40
Q

List common tx options for problematic 3rd molars (4)

A

Assessed in GDP then;
- Referral to OS or maxfax (depends of px preference) or specialist practice
- Clinical review of signs and symptoms - monitor (if tooth not being extracted)
- Removal of M3M to Extraction of maxillary third molar
- Coronectomy: considered when roots in close relation to the IDC

41
Q

What is involved in informed consent before 3rd molars extractions/surgery? (9)

A

Explain procedure to patient (benefits and risks)
- If tooth is likely to need sectioned explain this, explain that It will feel similar to a filling with the sound, vibration and water.
- Give the patient an idea of what to expect during the procedure
- Explain any minor surgical procedure, flap, possible drilling, sutures, etc

offer the chance for a CBCT if the roots are in close proximity to the IDC

explain Peri-op complications:
- (If 2nd molars have large restorations) explain risk of restoration fracture, reassure that a temporary will be placed and will be repaired once socket heals
- In edentulous/atrophic mandible, aberrant lower 8 close to lower border of mandible
- If a large cystic lesion is associated with the wisdom tooth, explain risk of jaw fracture.
- post op complications/what to expect

42
Q

What are the post op complications provided after a M3M surgery? (11)

A
  • Pain (variable amounts)
  • Swelling (variable amounts): normal up until 2 weeks after surgery
  • Bruising
  • Jaw Stiffness/limited mouth opening: should improve between 1-2 weeks
  • Bleeding
  • Infection
  • Dry Socket (localised osteitis): commonly occurs in 3rd molar mandible
  • Altered taste (rare)

Main risk: Nerve damage - Numbness (anaesthesia) or tingling (paraesthesia) of lower lip, chin, side of tongue (sensory damage NOT motor)
Demonstrate the areas that will be affected
- Dysaesthesia (rare) – painful, uncomfortable, unpleasant sensation of lower lip, chin, tongue; sometimes neuralgia type pain.
- Hypoaesthesia (reduced sensation) or heightened sensation (increased sensation).

43
Q

What % of patient experience temporary nerve damage to the inferior alveolar nerve after M3M surgery?

A

10-20%

44
Q

What % of patient experience permanent nerve damage to the inferior alveolar nerve after M3M surgery?

A

< 1%

45
Q

How long does it take for nerve damage to recover post M3M surgery?

A

commonly 9 months
can take up to 18-24 months (after this time no further recovery likely)

46
Q

What should we include in a 3rd molar referral? (4)

A

As much info as possible

  • S: situation: describe what is occurring (situation) i.e. 23 y/o male with pair ffrom lower left
  • B: background: History of presenting complaint
  • A: assessment: what you have found on examination (tooth, angulation, eruption status, disease i.e. caries etc)
    Include relevant MH, DH, SH and clinical examination findingsin this section
  • R: recommendation: your opinions on what should be done and what px wishes to be done
47
Q

Why is LA placed independent of the type of sedation selected? (2)

A

For local pain relief and haemostasis.

48
Q

List the steps for sugical removal of third molars

A
  1. LA
  2. Access (flap)
  3. (if bone removal is needed)
  4. Check socket
  5. Debridement
  6. Suture
  7. Haemostasis & post operative instructions
49
Q

How do we gain surgical access to a 3rd molar?

A

Lifting a buccal muco-periosteal flap (and sometimes a lingual flap)
2/3 sided

50
Q

What is the risk associated with raising a lingual mucoperiosteal flap?

A

The risk of the lingual flap damaging the lingual nerve.

51
Q

List the steps for raising a buccal mucoperiosteal flap.

A
  1. Use a scapel in 1 continuous stroke around the neck of the tooth.
  2. Start at the base of the relieving incision to raise the flap from bone.
  3. Then reflect distally.
52
Q

What instrument do we use to reflect the tissue of a flap and why?

A

Ash’s periosteal elevator firmly on bone to avoid disection and trauma to the tissues.

53
Q

What instruments are used for retraction of a flap?

A

Minnesota retractor
Rake retractor
Ash’s periosteal elevator.

54
Q

You have lifted a flap but further access is needed, what do you do?

A

Remove bone by cutting a buccal gutter.

55
Q

What type of handpeice is used for surgical bone removal.

A

An electric straight handpeice with a saline cooled bur.

56
Q

What is the buccal gutter and how do we produce it?

A

This is a narrow area of bone removal around the tooth to provide a point of application for placement of elevators.

To produce we keep a round bur in contact with the tooth the full way round the tooth from distal to mesial to ensure it is as narrow as possible.

57
Q

When would we divide the tooth in the surgical extraction?

A

When after bone removal it is still not possible to remove the tooth with elevators and forceps .

58
Q

How can we divide the tooth?

A

Split the crown and the root.
If still no space…
Split the distal and mesial (removing distal gives space to remove the mesial)

59
Q

How do we debride the socket after extraction?

A

Physical debridement-
Remove sharp bony edges using bone file or handpiece.
Soft tissue debris- using mitchell’s trimmer or victoria curette.
Irrigation-Apply sterile saline into the socket and under the flap
Suction- Aspirate under the flap to remove debris & check socket for retained apices etc

60
Q

Describe the incisions made for a 3 sided flap.

A

Distal relieving incision.
Incision at the neck of the tooth.
Mesial relieving incision

61
Q

Describe the incisions made for an envelope (2 sided flap)

A

Distal relieving incision
Incision around the neck of tooth.

62
Q

What sutures are used to close a 3 sided flap?

A

Suture at:
* Distal relieving incision
* mesial relieving incision

If you still see a gap/bone after placing the mesial incision you can place another suture.
If the papillae is free, you may chose to put a suture over the papillae.

63
Q

What sutures are used to close a 2 sided flap?

A

1 relieving incision
1 across the back of 7.

64
Q

What Post-operative instructions is specific to wisdom teeth?

A

Your jaw may hurt for 2-3 weeks (this is expected due to location of wisdom teeth. )
If there is continued numbness in one area come back and see us.

65
Q

What is a coronectomy and when do select it as a treatment option?

A

When we remove the crown of the tooth and leave the root in the mouth

When there is a risk of IADN damage with removal of the wisdom tooth.

66
Q

Compare a coronectomy and decoronating a tooth?

A

We remove all the enamel in a coronectomy - 3-4mm below enamel

When we decoronate a tooth (for tooth division) we leave a little bit of enamel to help us elevate and orientate the roots.

67
Q

List the steps involved in a coronectomy (6)

What is the clinical follow up period? (3)

A
  1. lift flap - standard wisdom tooth (2/3 sided)
  2. Transect the tooth 3-4mm below the enamel of the crown and elevate off without mobilising the roots
  3. Leave the roots with pulp untreated (to heal over)
  4. Irrigate the socket with saline
  5. Replace the flap and suture
  6. arrange follow up

Follow up:
- Review 1-2 weeks
- Further review 3-6 months
- Then 1 year

68
Q

What are the risks associated with a coronectomy? (4)

A

• If the root is mobilised during crown removal the entire tooth must be removed sicne it increases the infection risk (more likely with conical fused roots)

• If procedure goes to plan and roots left behind there could still be a risk of infection (rarely seen) and symptoms could persist = another procedure is required to remove roots.

• Can get a slow healing/painful “socket” = dry socket

• The roots may migrate later and begin to erupt through the mucosa; and may require extraction at a later date (can be a positive – however another surgical likely)

69
Q

Why is essential to get a radiograph prior to upper third molar extraction

A

Root morphology of 3rd molar teeth is so variable (No of roots/shape of root/divergent root/ curved roots)

My BDS4 (57 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions