ORS03 - Lecture 3 - Principles of Exodontia Flashcards
What factors affect the difficulty of an extraction?
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
What are the 2 types of tooth extraction?
Routine - forceps or elevation
Surgical - sectioning of tooth or raising mucoperiosteal flap
Describe the process of extraction (9)
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
Which types of forceps have beaks on the blades? (1)
Molar forceps - the beak engages with the top of furcation
Upper molars -> beak on buccal side (as this is where the furcation is)
What are the 3 types of forceps?
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)
What is the function of Forceps? (3)
Blade tip engages with root of the tooth (not crown)
It wedges in the PDL space
Disrupts/breaks PDL + dilates boney socket
What are the possible sequence of instruments that can be used for forceps extractions? (3)
Forceps alone
Elevation -> forceps
Elevation -> luxation -> forceps
What is the function of elevators and luxators?
Further widen the socket
Describe how you would ensure your using forceps correctly (5)
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
What are the 5 different types of forcep movements?
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
Why do you always move forceps bucally first? (1)
Buccal bone is much thinner than palatal or lingual bone
When should you use a Cowhorn instead of Forceps?
Badly broken down crown
What are the 2 types of Cowhorns?
Lower Cowhorn - pointed blades engage with furcation
Upper Cowhorn - grips around palatal root and engages furcation
How does the chair and head position differ during maxillary and mandibular extraction?
Maxillary Extraction
Chair -> more reclined + higher
Head -> chin up
Mandibular Extraction
Chair -> less reclined + lower
Head -> chin down
How does the position of dentist change for maxillary and mandibular extractions? (2)
Maxillary extractions -> infront of patient
Mandibular extractions -> behind patient
Give 2 functions of the non-dominant hand during extractions
Support alveola
Retraction of soft tissues
What is the function of Elevators? (4)
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.
What are the 3 main types of elevators?
Couplands -> insterted horizontally (right angle) to the CEJ (between bone + tooth) and rotate
Warwick James and Cryer -> small tip of blade is 90o to handle and is sharp used for retained roots
How do Luxators differ to Elevators? (4)
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
Compare Elevators and Forceps
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),
What needs to be checked when tooth is removed from the socket? (3:4)
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)
What 3 things do you need to consider for flap designs? (3:2:1)
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
What are the 3 flap designs?
Three sided flap
Two sided flap
One-sided (envelope) flap
Describe Bone Removal during surgical extraction
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
