L24 Surgical orthodontics

Question 1

Which teeth are most commonly impacted?

Answer 1

• 3rd molars
• Canines
• Incisors

Question 2

What are the complications of impacted teeth?

Answer 2

• External resorption of surrounding teeth
• Infection
• Cyst
• Loss of arch length
• Periodontal defects

Question 3

How are impacted teeth assessed?

Answer 3

• Clinically and radiographically
• Check the depth of the tooth and associated anatomy e.g. ID nerve, maxillary antrum etc.

Question 4

What are the indications for 3rd molar extraction?

Answer 4

• Recurrent episodes of pericoronitis
• Caries in 2nd or 3rd molar
• Distal 2nd molar perio
• Associated pathology e.g. cyst
• Prior to orthognathic surgery

Question 5

What soft tissue band can cause a diastema?

Answer 5

The upper labial frenum

Question 6

What are the effects of a lower lingual frenum?

Answer 6

Tongue tie
Speech impediment

Question 7

Why might someone still have a deciduous tooth beyond the expected age?

Answer 7

• Congenitally missing teeth
• Supernumerary teeth
• Displacement
• Delayed shedding
• Ankylosis

Question 8

Which teeth are most commonly congenitally missing?

Answer 8

• 3rd molars
• 2nd premolars
• Maxillary lateral incisors
• Mandibular central incisors

Smallest tooth in the series

Question 9

Which tooth might erupt through a sinus tract into the buccal sulcus?

Answer 9

Canine

Question 10

What are the 2 theories behind canine displacement palatally?

Answer 10

• Guidance theory: adjacent lateral incisor should guide the canine, warning sign - diminutive crown
• Genetic theory: displaced canine commonly seen as part of a wider variety of features with high incidence of congenitally missing teeth, peg shaped lateral incisors and a family history

Question 11

What is the general theory for buccally impacted canines?

Answer 11

Crowding = buccal displacement

Question 12

What are the possible effects of trauma to the deciduous incisors on the permanent teeth?

Answer 12

Intrusive injury to the deciduous incisor can cause:
- Retention of the deciduous tooth
- Dilaceration of the permanent tooth

Question 13

Delayed tooth shedding and late eruption of teeth is seen in association with which other conditions?

Answer 13

• Cleft lip and palate
• Down’s
• Hypopituitarism

Question 14

What is ankylosis?

Answer 14

The fusion of the deciduous tooth to surrounding bone.
Ankylosed teeth will be below the level of the occlusal plane, more difficult to clean.

Question 15

If an impacted canine causes resorption of the lateral incisor root, can the lateral be saved?

Answer 15

No

Question 16

What radiographic sign indicates spontaneous eruption into an ideal position of a buccally impacted canine?

Answer 16

Canine cusp tip distal to the long axis of adjacent lateral incisor = 90% chance of eruption into improved position spontaneously

Question 17

How do you surgically expose a canine?

Answer 17

• Localise the tooth
• Exposure using a flap, or excise a window of mucosa
• Pack the defect with Whiteheads varnish or Coe Pak
• Immediate attachment of ortho bracket +/- chain

Question 18

Describe the basics of orthognathic surgery.

Answer 18

• Jaw broken (traumatic)
• Sagittal split osteotomy
• Protects the ID nerve (to a degree)
• IOFTN used to see who qualifies, must be teen or audult
• 12/18 months of ortho
• 6/12 months of ortho post op
• Semi-rigid fixation using plates
• Facial changes

Question 19

What is an occlusal cant?

Answer 19

Maxillary or mandibular arch on a slope/off centre