ORS03 - Lecture 3 - Principles of Exodontia

Question 1

What factors affect the difficulty of an extraction?

Answer 1

1) Tooth

Root morphology

Grossly carious crown

2) Supporting structures

Gingival tissue - overgrowth

PDL - periodontal disease

Bone - periodontal disease or age -> young = denser

3) Proximity to adjacent structures

Teeth - restorations/mobility

Vital structures - inferior dental nerve, maxillary antrum, infra-orbital nerve

4) Access

Limited mouth opening (trismus) -> spread of infection, trauma, microstomia, oral sub mucous fibrosis

Tooth positions -> crowded, impacted

Question 2

What are the 2 types of tooth extraction?

Answer 2

Routine - forceps or elevation

Surgical - sectioning of tooth or raising mucoperiosteal flap

Question 3

Describe the process of extraction (9)

Answer 3

1) Use elevators and/or forceps

2) Apply apical pressure along the long axis of the tooth

3) The position breaks apically along roots

4) This severs the periodontal ligament and begins to dilate the socket

5) For multi-rooted teeth-> lateral movement of the tooth - in buccal and palatal directions (i.e. figure of eight or circular movemenet)

6) For round single rooted teeth -> rotation movement

7) This will allow you to get complete dilation of the socket

8) Use controlled force to slowly withdraw tooth (avoiding injury) - final extraction always towards buccal side, outwards and downwards.

9) Supporting the jaw/alveolar bone with other hand

Question 4

Which types of forceps have beaks on the blades? (1)

Answer 4

Molar forceps - the beak engages with the top of furcation

Upper molars -> beak on buccal side (as this is where the furcation is)

Question 5

What are the 3 types of forceps?

Answer 5

Upper forceps - blade in long axis of handle

Lower forceps - blade at right angle to handle

Root forceps - thin blade (for anterior roots or split posterior roots)

Question 6

What is the function of Forceps? (3)

Answer 6

Blade tip engages with root of the tooth (not crown)

It wedges in the PDL space

Disrupts/breaks PDL + dilates boney socket

Question 7

What are the possible sequence of instruments that can be used for forceps extractions? (3)

Answer 7

Forceps alone

Elevation -> forceps

Elevation -> luxation -> forceps

Question 8

What is the function of elevators and luxators?

Answer 8

Further widen the socket

Question 9

Describe how you would ensure your using forceps correctly (5)

Answer 9

1) Use correct forceps (upper beak -> parallel to handle, lower beak-> right angle to handle)

2) Beak engages with root - ensure you have good surface contact

3) The position of the beak should be in the same direction as long axis of the tooth

4) Push the forceps apically -> this prevents beak sliding and root fracture

5) Every movement of forceps should result in tooth movement

Question 10

What are the 5 different types of forcep movements?

Answer 10

Conical (cone-shaped) teeth -> rotate (tears PDL)

Upper premolars -> buccal:palatal or lateral movement (expands socket)

Upper molars -> buccal movement

Lower incisiors -> buccal:lingual movement then rotate

Lower molars -> buccal:lingual movement

Question 11

Why do you always move forceps bucally first? (1)

Answer 11

Buccal bone is much thinner than palatal or lingual bone

Question 12

When should you use a Cowhorn instead of Forceps?

Answer 12

Badly broken down crown

Question 13

What are the 2 types of Cowhorns?

Answer 13

Lower Cowhorn - pointed blades engage with furcation

Upper Cowhorn - grips around palatal root and engages furcation

Question 14

How does the chair and head position differ during maxillary and mandibular extraction?

Answer 14

Maxillary Extraction

Chair -> more reclined + higher

Head -> chin up

Mandibular Extraction

Chair -> less reclined + lower

Head -> chin down

Question 15

How does the position of dentist change for maxillary and mandibular extractions? (2)

Answer 15

Maxillary extractions -> infront of patient

Mandibular extractions -> behind patient

Question 16

Give 2 functions of the non-dominant hand during extractions

Answer 16

Support alveola

Retraction of soft tissues

Question 17

What is the function of Elevators? (4)

Answer 17

Uses axel and wheel motion (i.e rotatory forces) + lateral movement

At right angles to the long axis of the tooth + elevated distally (on distal surface of root)

This helps facilitate extraction with forceps because it ->

Breaks down periodontal ligament (PDL) + widen the socket coronally + allows access of forceps at an apical level.

Question 18

What are the 3 main types of elevators?

Answer 18

Couplands -> insterted horizontally (right angle) to the CEJ (between bone + tooth) and rotate

Warwick James and Cryer -> small tip of blade is 90^o to handle and is sharp used for retained roots

Question 19

How do Luxators differ to Elevators? (4)

Answer 19

Flatter and sharper blade

Inserted vertically along long-axis of the tooth (not horizontally)

Gently rotate the handle and advance blade apically towards-> apex of the root to induce mobility

The sharp blade disrupts the PDL

Question 20

Compare Elevators and Forceps

Answer 20

Elevator - applies force between the tooth and surrounding bone of the jaw so theres less directional control and root is withdrawn along its own path.

Forceps - allows operator to grab the tooth and apply force directly to the tooth - thus allows you to dictate the direction of movement, however this force can be transmitted to the jaw (thus jaw needs to be stablised),

Question 21

What needs to be checked when tooth is removed from the socket? (3:4)

Answer 21

Apices (3)

If its intact

Smooth

Round (no sharp edges)

Socket (flushed with saline) (4)

Retained roots

Soft tissue

Fragments of tooth/debris

Hole in antrum (oral antral communication)

Question 22

What 3 things do you need to consider for flap designs? (3:2:1)

Answer 22

1) Broad base

Uninterupted blood supply

Ischaemic necrosis

Good access to operating field

2) Adequate size

Large enough to visualise the area in question + adjacent teeth

Too small -> tension, tear, breakdown, poor healing

3) Incision margins are on sound bone

If bone is being removed, incisions need to away from the site

Question 23

What are the 3 flap designs?

Answer 23

Three sided flap

Two sided flap

One-sided (envelope) flap

Question 24

Describe Bone Removal during surgical extraction

Answer 24

1) Be minimally invasive

2) Prepare gutter (bone removal):

To allow applicaiton point for instruments

Circumferentially -> around retained roots

3) Use rose head (initially) then fissure bur