ENDO surgery Flashcards
what are the 4 aims of endodontic tx?
access, clean and disinfect the root canal system
reduce the number of microorganisms
remove necrotic tissue
seal the system to prevent infection
what are the 5 causes of persistent PA radiolucency in endo treated teeth?
intraradicular infection
extraradicular infection
foreign body reaction
true cyst
fibrous scar tissue
how do you differentiate cystic and non-cystic periradicular lesions?
cannot do it clinically with radiographs
must be histopathologically
what are the 2 types of periradicular cysts?
true cyst - cavity completely enclosed in epithelial lining
pocket (bay) cyst - epithelium-lined cavities that are open to the root canal
what are the indications for endo surgery?
failure of previous endo tx - if retreatment not possible
anatomical deviations - that prevent cleaning and obturation
procedural errors - ledges, blocks, perforations, file breakages, overfills
exploratory surgery - identification of root fractures
what are the contraindications to endo surgery?
anatomical factors - proximity to neuro bundles, thick cortical bone, difficult access
inadequate periodontal support
non-restorable tooth
medical history - blood disorders, recent MI, cancer tx
skill and ability of surgeon
where do you find thick cortical bone?
lower molar region
what lens system do loupes use?
convergent lens system (Greenough system) - users eyes must converge
what is the magnification on a microscope detrmined by?
power of the eyepiece
focal length of the binoculars
magnification changer factor
focal length of the objective lense
what is the range of magnification in a microscope?
x3 - x30
what are the preoperative medications for endo surgery?
anti inflammatory agents - ibuprofen
antibacterial rinses - chlorhexidine
premedication - 5mg diazepam (if pt very nervous)
why do we tell pts to take ibuprofen prior to endo surgery?
it inhibits cyclo-oxygenase, preventing the formation of inflammatory mediators
when do we tell pts to rinse with chlorhexidine prior to endo surgery?
morning of and 30 mins before appt
what is the purpose of LA during endo surgery?
prevents pain
obtains presurgical haemostasis
what are the flap design rules for endo surgery?
- flap never crosses bony defect
- releasing incisions over concave bone surfaces and not convex
- end of the vertical incision at gingival crest should curve 90 degrees to gingival contour
- the other end should not enter the mucolabial fold
- base must be as wide as its free edge and vertical relieving incisions and follow vascularisation network
- periosteum must be raised with the flap
- retractor must rest on bone and not soft tissue
what does a full mucoperiosteal flap include?
mucosa, connective tissue and periosteum
when is a flap known as intrasulcular?
when the horizontal incision involves the papillae and sulcular epithelium
describe a papilla based incision?
a shallow first incision at the base of the papilla and a second directed to the crestal bone
intrasulcular incision at cervical area of tooth
x2 relieving incisions
what is the benefit of papilla based incisions?
prevents gingival recession
good healing
what are the 6 types of surgical blades?
CK 1 - buccolingual incisions
CK 2 - all incisions
CK 3 - all incisions
CK 4 - mucogingival incisions
CK 5 - posterior
CK 6 - palatal
what instrument is used for flap elevation and how is it placed?
Prichard periosteal elevator
placed at the junction of the horizontal and vertical incisors, concave surface against the bone, beneath the gingivae at line angle
when elevating flaps, how do we prevent bleeding and speed up healing?
reflect the whole periosteum, apically with a slow, firm motion
what is a osteotomy?
removal of cortical plate to expose root end
during an osteotomy, what instruments are used to remove granulation tissue, foreign bodies and bone particles?
curettes
during an osteotomy, when can you clean out the lingual aspect?
after root resection
during an osteotomy, how do you know all tissue has been removed?
bleeding will stop
how is granulation tissue removed?
curettage
what is preop haemostasis?
LA
what are intraoperative haemostatic agents?
epinephrine pellets
ferric sulfate
calcium sulphate
surgical wax, thrombin, gelfoam, collagen (not as effective)
what does root end resection aim for?
to create an environment conductive for regeneration of periodontium, alveolar bone, PDL and cementum
how much root is resected?
3mm perpendicular to long axis of tooth
how do you examine to ensure resection is complete?
use dye (1% methylene blue) - PDL shows colour
what instrument is used for root resection?
impact air surgical handpiece 45 degree - Lindemann bur
what is the aim of ultrasonic retrocavity prep?
aims to create a clean, well conformed type 1 cavity into the sectioned root
how deep should the retrocavity be?
3mm
what type of ultrasonic is used for retrocavity prep?
Piezo ultrasonic units and KiS tips - tips coated in diamond and zirconium nitride
what is the advantage of using ultrasonic tips for retrocavity prep?
better access
ultrasonic cleaning
preps follow canal anatomy
isthmus prep
parallel walls - superior retention
what materials can be used for root end filling?
amalgam
zinc-eugenol
MTA - best option
how long does MTA take to set?
3 hours
if a pt returns with post-op pain following endo surgery what do you do?
provide ibuprofen
instruct to continue with pain med for 48 hours
long term pain as a result of damage to peripheral nerves occurs rarely
post op instruction for swelling?
intermittent application of cold dressing (20 mins on 20mins off)
post op instruction for bruising (ecchymosis)?
reassure pt, self limiting resolves within 2 weeks
how long may paraesthesia last following endo surgery?
4 weeks
