Planning surgery and flap design Flashcards
What does MOS stand for?
minor oral surgery
What may MOS involve?
surgical dentistry
- trans-alveolar surgical removal
- surgical extraction
- peri-radicular surgery/apicectomy
- implantology
- soft tissue surgery
What may the goal of MOS be?
- removal of a tooth/root
- part of a tooth (coronectomy)
- apicectomy of a tooth
- peri-radicular surgery
- preservation of surrounding structures?
What must be asked about your goal when planning a surgery?
is it achievable in a sensible time limited window (approx. 45 mins)?
- based on assessment
- patient tolerance
What is involved in medical assessment during surgical planning?
- medically fit?
- correct patient position possible?
- patient able to be positioned for a length of time?
- able to achieve anaesthesia without incident?
- able to perform procedure without;
- exsanguination
- overwhelming infection
- excessive anxiety
- medical compromise
What access considerations should be made during surgical planning/assessment?
- physical access
- visual access
- emotional access - patient able to cope?
- social access - wider patient support
What is involved in the environmental assessment during surgical planning?
- instrumentation
- equipment
- support
- team
- skills/training
- anaesthesia/modality
- time
- distractors
- competing interests
What is involved in radiology assessment during surgical planning?
- information readily at hand
- film type (DPT/IOPA/CBCT)
- multiple views
- localisation - parallax
- obstacles
- withdrawal
What is planned last during surgical planning?
incision
‘cut is first… but is planned last’
What are the steps of a surgical tooth removal?
- flap design
- incise and reflect
- account for obstacles
- methods to overcome obstacles i.e. bone removal
- position of instruments to elevate
- path of withdrawal
- tooth removal
What are the steps of surgical tooth removal planning?
- tooth removal
- dependent on path of withdrawal
- dictates position of instruments to elevate
- influences methods to overcome obstacle i.e. bone removal
- account for obstacles
- inform incision and reflection
- flap design
What are the 7 basic principles of making an incision?
- scalpel - standard pen grip
- no 15 and no 11 generally
- crevicular incisions
- relieving incisions
- perpendicular mucosal surface
- single sweep rather than multiple cuts
- be wary of leading edge cutting
What kind of incision is this?
crevicular incision
What is a crevicular incision?
intention is to cut somewhat parallel to the long axis of the tooth in the gingival crevice, and to cut down onto sound bone through periosteum
What is a relieving incision?
runs from the crevicular area towards the apices of the teeth in order to allow some relief to manipulate the flap and expose the alveolar bone, generally full thickness (mucosa and periosteum)
Why are incisons generally perpendicular to the mucosa?
so as not to introduce a shelving of the tissues
What do we need to be wary of leading edge cutting?
often only a small part of the cutting edge is used when making an incision, if you aren’t careful the part you aren’t using may cut tissue you don’t intent to
e.g. purposefully cutting with red part but accidentally cutting another area with green part:
What kind of incision does the blue line represent?
crevicular incision - full thickness onto the underlying crestal bone
What style of flap would the blue incision made?
no relieving incision therefore an ‘envelope’ flap
What type of flap does this represent?
envelope flap
What kind of incision is labelled 2?
relieving incision
What kind of flap would these incisions make?
two sided flap
What kind of flap is this?
two sided flap
What does a two sided flap give than an envelope flap doesn’t?
exposes more alveolus, allows more access to the bone during procedure
What kind of incision is labelled 3?
a second relieving incision
What kind of flap would these incisions make?
three sided flap
What kind of flap is this?
three sided flap
What is the benefit of a 3 sided flap?
allows exposure/access of much more alveolus, possibly even up to the root apices
What are the 12 basic principles of flap design?
- flap broad base
- ensure blood supply
- extend 1 unit either side
- incision margins supported
- avoid/include important structures
- flap without tension
- include papilla
- incisions avoid leaving areas avascular
- relieving incisions
- anterior relieving incision generally
- be mindful of anatomy/cosmesis
- extent dictated by relief
What do we mean by ‘broad base for blood supply’?
blood supply has a tendency to run sulcus to crest, to accommodate a larger blood supply you want to base of the incision to be broad to allow better blood supply to the peripheries of the flap
want to base of the incision to be as broad/broader than the crestal area of the flap
What do we mean by ‘extend 1 unit either side’?
extend flap approx. 1 tooth either side of the tooth being worked on
What do we mean by ‘incision margins supported’?
want the incision margins to be supported, ideally by bone, when you place them back in their original position
extending the flap 1 unit either side (blue) aids in this as a flap cut only beside the tooth (red lines) may result in the flap being placed over a bony defect (green)
What might happen if incision margins are not supported?
soft tissue overlying a bony defect may fall into this, resulting in exposure of adjacent tooth root surface etc
What is an example of an important structure to avoid or include when cutting a flap?
mental neurovascular bundle
How does local anatomy influence our actions?
guides where we can or can’t place incisions safely
How should flaps be manipulated without tension?
gently retract, don’t stretch
when returning them to original resting site they should not be under tension or stretched further than their original position
Why should papilla be included in a flap?
- help with flap relocation
- excellent suture points
What does this show?
papilla being included in the flap and subsequently being used as suture points
How may we avoid leaving areas of a flap avascular?
don’t cut a papilla like this
Where are relieving incisions generally placed?
anteriorly
What must be considered when planning path of withdrawal?
- eruption path
- exit path
- guides elevation point/instrumentation
What do the green arrows represent?
paths of withdrawal for each root
What is the position of instruments to elevate from guided by?
eruption path/path of withdrawal of the tooth
Where are instruments to elevate often placed?
mesially
What is the importance behind identifying elevation points of a tooth during surgical planning?
guides bone removal to achieve access to elevate points
What is labelled in pink?
elevation points/position of instruments to elevate
Although it is placed mesially so is the ideal elevation point, why would you be careful when elevating from the point marked in pink?
very close to the sinus
What do the pink markings here show?
depth from height of the crest to the elevation point, bone therefore must be removed to access the elevation point
What are some extrinsic obstacles?
- bone
- soft tissues
- anatomic features
- adjacent teeth
- pathology
- space (lack of)
- location (palatal/lingual)
- maxillary sinus
- IAN bundle
What are some intrinsic obstacles?
- crown (size, shape)
- roots - number, morphology, angulation
- pathology
- caries
- resorption
- ankylosis
Why are endo treated teeth potentially challenging to remove?
more brittle/weak, break more readily under force when extracting
What can be done to overcome obstacles?
- bone removal
- sectioning
- soft tissue
- care!!!
- technical skill
- awareness anatomy
- avoidance (e.g. coronectomy to avoid IAN)
What kind of flap do the blue incisions give?
triangular flap
What tooth are triangular flaps usually used for?
mesio-angular third molars
What does the yellow area represent?
where bone will be removed (removal of obstacle)
What does the pink asterisk represent?
the application point for elevators which will be accessible after bone removal
What kind of flap is this?
envelope flap
For lower 8s, what’s the difference between the triangular flap and the envelope flap?
envelope flap allows for more bone removal anteriorly
Why would a flap for a lower 6 extend forward to the 4?
so the relieving incision is not coming close to the mental neurovascular bundle
What kind of flap is this?
2 sided flap to access the 6, extending to the 4 to avoid the mental bundle
What kind of incision is this?
slash- style incision for UE or PE upper 8s
