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294 Cards in this Set
- Front
- Back
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an immature apex has?
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no natural constriction at the end so cannot achieve RCT filling without leaking into bone..
*in young patients maintain the tooth as long as possible |
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well what can we do with a wide apex?
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we can do flap surgery and fill the hole. You can take 2 pieces of GP and custom make your own GP. Heat the GP.
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Regenerative antibiotics
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revascularization/regeneration procedure for necrotic teeth using antibiotic paste in root canal system to create environment for angiogenesis.
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apexification
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a method of inducing apical closure by the formation of osteocementum or a similar hard tissue of an incompletely formed tooth in which the pulp is non vital.
NECROTIC PULP |
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what are the 3 objectives of treatment?
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fill the root canal system in 3 dimensions
keep the filling material in the root canal system stimulate the formation of hard tissue barrier /calcified tissue at apex |
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what is the medicament that is placed in this technique?
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calcium hydroxide
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if the tooth you are treating for apexification has a periapical lesion, what else would you include in your diagnoses?
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asymptomatic or symptomatic apical periodontitis
chronic apical abcess |
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because the apex is so big, what can you do with large files (80-140) to determine working length?
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the files may be held in place with cotton balls stuffed in cavity
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are apex locators helpful in these teeth?
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NO
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is it the typical 3 sizes beyond the first file that binds at WL in these teeth?
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No , its just enough to engage the canal walls and place medicament in the canal.
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How can you dry the canals in these teeth?
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Large paper points used backwards
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describe the contemporary approach to apexification
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-CaOH paste is placed in the canals to aid in canal disinfection
-MTA is placed into apical part of canal to create an apical plug or barrier |
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what is important to remember about CaOH and safety?
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CANNOT GET IN PX EYE! the pH is 12.9 -->avoid skin and eyes
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can you use MTA when there is still pus?
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NOPE , use CaOH first and then make sure its all dried up i the canal
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dens invaginatus
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a "tooth within a tooth" . It increases the risk of pulp disease and can complicate any root canal. It can break off and cause isolated necrosis then full necrosis
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What are the 3 uses for Ca OH?
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1. vital pulp therapy (indirect, direct, pulpotomy)
2.Open apex (apexification) 3.intracanal dressing |
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Apexogenesis
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vital pulp therapy of an immature adult tooth directed to maintain pulp vitality and allow the tooth root to mature and develop
VITAL PULP |
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is endo usually necessary for apexogenesis?
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no
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where is the access made to in these teeth?
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to the level of vital tissue
*in multirooted teeth , remove pulp from the chamber leaving pulp in root canals *in single rooted teeth remove affected pulp from the chamber to level of healthy pulp |
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do u place a hand file in these teeth to determine working length?
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no . do not damage vital pulp tissue in the canal space
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How do you control hemorrage in these teeth?
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pressure with NaOCL moistened cotton pellet 5 minutes
CaOH2 powder |
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What do you do after placement of the medicament (CaOH2) ?
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you wash it out and put a hard setting material such as Dycal over the remaining pulp stump. IRM can also be used as a base and temp filling material
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a permanent restoration is often placed at the first visit for these teeth after?
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glass ionomer base followed by bonded resin material is placed
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when would endodontic treatment be necessary in these teeth?
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-pulpal necrosis
-periapical involvement with lesion or sinus tract -symptomatic pulpitis |
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what can you use for pulp capping in these teeth?
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-MTA
-Biodentine -Tricalcium phosphate |
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what is needed for assessment of dentin bridge formation, physiological root development and pulpal changes?
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continual evaluations of each case
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what is one helpful way we can tell if pulp is vital?
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continuued root development
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so if you see a root that is only filled half way..what should be on your differential?
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it ofcourse could be a crummy filling by a dentist, however it could also be apexogenesis and the root coul be fine. Make sure to assess the root formation on the rx.
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if a tooth has a radiopacity in the crown on an xray, it responds to cold-what is your differential?
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most likely a dens invaginatus bc the pulp tissue surrounding it is vital but the periapical tissue is infected. Treat these!
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highest anatomic variation
roots often fused, short curved and malformed |
mandibular 3rd molar
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mesial root (MB and/or ML)-usually curves distally
distal root (DB and or DL)- apex may curve buccally so beware on rx *what tooth? |
mandibular 2nd molar
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can you diagnose based on pan?
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no u need to take a PA
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what is an exception to the law of symmetry on a mandibular 1st molar?
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the canal orifice of the distal lingual root can be located further lingually
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mesial root-MB, ML and/or MM
distal root-DB and/or DL-apex may curve buccally can have 5 canals! *what tooth? |
mandibular 1st molar
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where should the base of your triangle be on mand molar?
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mesial
-start with rectangular and move to rhomboid if needed |
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6 classifications in endo diagnosis
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1. normal pulp
2. reversible pulpitis 3.irreversible pulpitis 4. hyperplastic pulpitis 5. pulp necrosis 6. periapical inflammatory disease |
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if a patient is positive to all vitality testing, but the discomfort lasts only as long as the stimulus applied-what should be top of your diagnosese?
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reversible pulpitis
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You think to yourself , that a RCT would be great ff
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yes! YOU DONOT NEED AN RCT for reversibly pulpitis. *conservation of pulp
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what are other features of reversible pulpitis?
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lack of spontaneous pain
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A patient comes in and responds to vitality testing with prolonged severe response to cold, no response to heat and a hyper active response to EPT. In addition there is prolonged pain with a change in temperature. What is top on your diagnosese list>?
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irreversible pulpitis.
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what else would u expect with irreversible pulpitis?
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-spontaneous pain ! and the pain will outlast the stimulus and throb
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what is your treatment for this?
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RCT!
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what will you expect while doing RCT?
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canals will bleed
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A patient has mild pain during mastication and you notice a fractured restoration and open carious lesion in a first molar. A spongy, soft tissue nodule is extruding from the tooth. the vitality tests are normal .What is this?
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Hyperplastic pulpitis. -chronically inflamed young pulp exposed by caries..
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Is the condition reversible?
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no. needs RCT. and canals will bleed
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A patient arrives at the office holding a large cup of ice water. They are complaining of continuous throbbing pain and can point to exactly what tooth is hurting them. What is it?
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Pulp necrosis
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what else would u expect?
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positive hot, percussion tests and no response to EPT. Canals can have pus or dry
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what would u do to treat?
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RCT
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A patient is asymptomatic with no response to cold, heat or percussion. There is no response to EPT. However, there is a lesion present on the radiograph. what is it?
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periapical inflammatory disease
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what would you expect if it was symptomatic Periapical inflammatory disease?
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the same as for pulp necrosis. So spontaneous pain, positive on vitality tests except EPT ...and cold relieves the pain.
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if its symptomatic , would you perform surgery?
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no, do an RCT
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endodontics view on cysts?
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they exist and can be and are usually resorbed
*oral medicine believes cysts can enlarge and grow as fluid fills the epithelial lined cavity |
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can you distinguish between a cyst and abscess on radiograph?
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no
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if the lesion grows on the radiograph then what is it most likely to be?
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cystic. and needs surgical intervention
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misperception, misinterpretation and incomplete diagnostic examination lead to
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misdiagnoses
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is NiTi more flexible than stainless steel?
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yes
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is stainless steal stronger than NiTi?
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no
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high torque instrument
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stainless steel
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low torque instrument
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NiTi
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advantages of crown down technique?
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-easier access
-improves distribution of irrigants -facilitates removal of canal contents |
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rotary speed of profile NiTi?
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300rpm
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rotary speed of profile vortex ?
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500 rpm
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cyclic fatigue
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stress to NiTi files around a curve= compression and tension
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how do you instrument canals that join with rotary?
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do the buccal and lingual canals to juncture with rotary file and finish with hand instrumentation
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4 cautions when using rotary profile nickel titanium .04 Tapers
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1. two canals that join
2. root canal anatomy with a double curve 3. overuse of files 4. over instrumentation at apical foramen |
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radicular cyst
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apical periodontits+cyst
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no symptoms does not mean there is no...
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bacteria
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3 irritations of the pulp
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1. physical
2. chemical 3. microbiological |
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How can bacteria be introduced to the pulp?? (8)
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1. caries
2. enamel surface caries 3. leakage 4. hair fracture 5. lateral canal 6. dentinal tubules 7. deep pocket to apex 8. bacteremia 9. trauma exposes the pulp |
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why is pulp like a jungle?
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hylauronic acid makes it very difficult for chemical material to travel in this ground substance. Good defence!
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what bacteria dominate in the bacterial flora in Apical perio?
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anaerobes
*enterics and yeast are absent |
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post treatment flora in AP?
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enterococcus fecalis (facultative)
yeasts |
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what is the structural problem of pulp?
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1 small apical foramen where all nerves and blood vessels enter. Its very limited in collateral circulation so body cannot repair
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what is the defense mechanism at root tip?
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the osteoclasts remove bone , the bone is being replaced by highly vascularized tissue.
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3 ways to spread infection out of root canal
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1. dentine canals
2. lateral canals 3 periapical area |
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a clinical diagnoses based on subjective and objective findings indicating that the inflammation should resolve and the pulp return to normal
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reversible pulpitis
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"" the vital inflamed pulp is incapable of healing . Lingering thermal pain, spontaneous pain, referred pain.
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symptomatic irreversible pulpitis
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"" the vital inflamed pulp is incapable of healing . no clinical symptoms but inflammation produced by caries, caries excavation , trauma.
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asymptomatic irreversible pulpitis
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a clinical diagnostic category indicating death of the dental pulp. The pulp is usually non responsive to pulp testing.
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pulp necrosis
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inflammation usually of the apical periodontium producing clinical symptoms including a painful response to biting and/or percussio palpation. May or may not be associated with a rx periapical radiolucent area
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symptomatic apical periodontitis
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inflammation and destruction of apical periodontium that is of pulpal origin. Appears as an apical radiolucent area and does not produce clinical symptoms.
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asymptomatic apical periodontitis
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an inflammatory reaction to pulpal infection and necrosis characterized by rapid onset , spontaneous pain, tenderness of the tooth to pressure , pus formation and swelling of associated structures.
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acute apical abscess
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an inflammatory reaction to pulpal infection and necrosis with gradual onset , little discomfort and pus in sinus tract.
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chronic apical abcess
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condensing osteitis
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diffuse radipaque lesion representing a localized bony reaction to low grade inflammatory stimulus usually seen at apex of tooth.
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what type of bur do you use on porcelien?
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diamond
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the max first premolar often has 2 canals. As high as ____%
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80%
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the mesial and distal of the max first premolar root are often _________
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concave
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the buccal root tip of max first premolar has _____curvature
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palatal
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what can you look for on radiographs to indicate to you there are two roots?
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2 periodontal ligament lines
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if root canals are close to the furcation, how should you taylor your instrumenting?
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instrument more Buccal LIngually.
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is it a short obturation that is the cause of Failure in RCT??
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FALSE, it is the "uncleaned, unfilled root canal system" that is the cause of failure
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how many mm of space need to be above the cotton pellet of an RCT in a premolar to incorporate a temporary filling?
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4mm
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what is the best option for access Temporary filling?
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you have the option of cavit, IRM etc, however a COMBINATION is often best such as Cavit+Ketac Silver
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Vertucci Type I
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a single canal
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Vertucci Type II
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two separate canals leave the pulp and join to form one at the apex
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Vertucci Type III
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one canal leaves the pulp, then splits into two, then joins again as one as they exit the canal
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Vertucci Type IV
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Two separate canals
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Vertucci Type V
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one canal leaves the chamber, and divides into two just short of the apex with separate apical foramina
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Vertucci Type VI
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two canals leave the chamber, then they merge, then they redivide right before apex to exit as 2 distinct canals
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Vertucci type VII
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one canal leaves the pulp chamber, then it divides, then it rejoins in the root, then it divides into 2 canals right before apex
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Vertucci type VIII
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3 separate canals
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a amdnibular premolar with a vertucci type V configuration has one canal leaving the chamber that splits into 2. where is the more difficult second canal located?
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along the lingual wall
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what is the easier canal to access on max premolar?
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palatal. Then do buccal
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what files could you use to remove pulp tissue from the isthmus of a mandibular premolar?
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use 10 or 15. also, instrument the B and L walls more than the center bc that is a danger zone due to the proximity of the furcation
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do not create a _______ canal system on premolars
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round.
*should be hourglass! |
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which canal would you obturate first in a premolar, the short or long?
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obturate the longer canal first
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dens evaginatus
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typical of premolars (extra cusp at pulp horn )
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which root of a max first premolar is better for a post and why?
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the palatal root, bc the buccal root has a deep invagination ~5.38 mm from the apex,
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scenarios where teeth without pulpal or periradicular pathosis may be considered for RCT?
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when preventative endo is performed to avoid almost certain pulpal involvement during subsequent crown fabrication
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why is extraction contraindicated for a patient on IV bisphosphonates or radiation?
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the ability of the bone to heal is affected, therefore RCT is preferred
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4 contraindications to endo
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non retorable teeth
inadequate perio support that is uncorrectable no future indication for the teeth (non strategic) vertical root fractures and amputation discussed |
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what are the major steps in root canal preparation?
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-access preparation
-working length determination -debridement -cleaning and shaping -->MAF |
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what are the major steps in root canal obturation?
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-master cone fit
-obturation (GP and sealer) -cleaning pulp chamber -temporary filling -final resto |
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what must be approved prior to RCT . This step provides coronal seal and protection of tooth structure and is considered a continuum of RCT
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a restorative treatment plan.*longterm prognosis of tooth usually crown or onlay
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what is the 5 standard PA series of rx for endo?
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1. pre treatment (straight and off angled)
2. trial file (PWL 15 file) 3. master apical file (post instrumentation) 4.master cone 5.post treatment |
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what rx need the rubber dam on?
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2. trial file
3. MAF 4. master cone |
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what should be on your tray for access preparation
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-mirror
-perio probe -cotton plier -DG 16 explorer -spoon excavator -rulers |
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a proper access cavity should never result in?
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unnecessary sacrifice of dentin
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what determines the outline form?
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pulp chamber anatomy
ex. max centrals are triangular and mand centrals are ovoid |
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serious errors in access preparation include?
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-failure to remove chamber roof
-crown or root perforation -chamber floor perforation -access not shown before proceeding to WL determination |
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how do you determine the PWL?
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the radiographic length (reference point), minus 1mm
*ex. 21 mm RL = 20 mm PWL |
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How do you determine the WL from the PWL?
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take a minimum 15mm trial file and place the rubber stopper at your PWL and take the trial file Rx.
we want the trial file to appear 1mm short of the rx apex |
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what if the trial file appears 1.5mm short of the rx apex?
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adjust by .5 mm longer for the WL
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what if the file appears more than 1.5mm shorter or longer than 1mm short of the rx apex?
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adjust the trial file then snap another rx
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why is WL set at 1mm short of the rx apex?
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the minor foramen or apical constriction can anatomically be located .5-2mm short of the rx apex
so we base it on an average distance of 1mm |
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what are the serious errors in determining WL?
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difficulty in achieving WL on2 canals
difficulty in achieving WL on 3 or more canals |
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root canal preparation consists of _______ and _________
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cleaning and shaping
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cleaning consists of?
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removal of infected soft tissues and organic debris
removal of infected hard tissues (dentin) |
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shaping consists of?
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enlargement of RC system to achieve conical form
maintain original pathway of canal retain the integrity of radicular structures |
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why do we want a conical , tapered form?
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-provides apical access for disinfecting irrigants
-creates space for the placement of medicaments -facilitates root canal obturation |
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what is the sequence of colors from 15-40?
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white
yellow red blue green black |
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square
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K file
file and balanced force |
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circle
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hedstrom
filing |
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triangle
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reamers
balanced force and reaming |
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what sizes are ss K files?
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6-10
60-140 |
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what sizes are Flex SSK files?
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15-25
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what sizes are Flex NitiK?
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30-50
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after every file in step back you must?
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irrigate with .2 -.5 cc of Na OCl
clean file with alcohol recapitulation (10 or 15) |
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serious errors in instrumentation
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the MAF is more than 1.2 mm off the WL.
deviations from original curvature apical perforation apical foramen enlarged |
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what do you do before fitting and forming the master cone in obturation?
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irrigate with NaOCL then dry the canal with paper points
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explain the fit and form of a master cone?
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grasp the cone at WL and test cones until you get tug back 1mm short of WL. Now, dip in chloroform and tamp the cone in and out of the canal several times to shape the apical portion of the cone. Now, add sealer and insert the MC the same way it was formed.
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when building a tooth up above the gingival margin, what materials should you avoid?
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avoid cavit, IRM due to poor compressive strength and adhesion
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so what would u recommend for build up?
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glass ionomer
composite amalgam |
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what are the Krasner and Rankow laws of pulp chamber floor anatomy?
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Law of symmetry 1
Laws of symmetry 2 Law of color change |
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law of symmetry 1
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orifices of canals are equidistant from a line drawn in a M-D direction through the centre of the chamber
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Law of symmetry 2
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orifices of canals lie on a line perpendicular to a line drawn in M-D direction
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law of color change
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color of pulp chamber floor (greyish) is always darker than the wall (yellowish)
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What are the krasner and rankow laws of pulp chamber floor anatomy?
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Law of orifices location 1-located at junction of walls/floors
Law of orifices location 2-located at angles of floor/wall law of orifices location 3-located at the terminus of the development fusion lines |
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what can you repair a perforation with?
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MTA
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if you notice in a mandibular molar that your canal orifices are not in the mesiodistal midline, what should u do?
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search for another orifice on the opposite side of the canal that is off the midline.
ex. you find an orifice located buccal, look lingually across the midline. |
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what is the key to instrumenting two canals that join apically ?
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identify and verify that the canals join before the canals are completely instrumented .
-put one file into WL, does the 2nd file go into WL? if the 2nd file stops short then prob 2 canals that join |
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describe sizing the apex
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use the same size SS hand file as the first rotary NiTi file that reached WL and see if it can also get WL. If it does then continue to larger files until one engages the apical 3rd at WL (1-2 sizes larger usually). This is the MAF
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you need to use trial files of different sizes for an x-ray for WL. Where would you put the larger file?
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straighter canal
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for a clinical patient, what must be placed before removal of rubber dam??
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a suitable access restoration with cavit , IRM etc
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"fast break"
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pulp anatomy on rx that seems to disappear part way down the root--->indicates 2 canals
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How do you know that a "fast break" is not a calcified canal?
|
a canal calcifies from coronal to apex .Therefore we would not expect to see radiolucency that disappears. you would see radiolucency that appears toward the apex.
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what % of mandibular anteriors have 2 canals?
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41.4%
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so when you find 2 canals that join, what do you do about working length?
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you have already found separate working lengths for each, but the point where the second file meets the first file is taken as the modified WL of the second canal
-choose the straighter canal to take to full WL. |
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what do u need to remember to do to the first canal, while instrumenting the second canal?
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recapitulate the first canal to prevent blockage. Irrigate both canals also
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what if you just instrumented 2 root canals that join to the same working length?
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you will create "hourglassing" apically so that GP cannot be condensed properly here. There will be a void in the filling apical to the constriction of the hourglass
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describe obturation of two canals that join
|
conefit the longer canal first and place the mastercone with sealer to WL. Do the same thing for the second canal to its modified WL. Now, spread the first canal and add an accesory cone. Only add accessory cone to the second canal if room permits. Take your trial cone film and check obturation
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if filed are not precurved you can get ______
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ledges
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nickel titanium files require?
|
balanced force technique
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what tissue are we disrupting while filing besides the pulp?
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predentin. Its organic and can house bacteria
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How can you renegotiate a canal with debris build up?
|
take a small file and use watch winding motion then take 1mm out and move up and down 40x to remove debris.
-irrigate |
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what sealer are we using?
|
resin based sealer: AH plus
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6 sources of pain that can be attributed to a tooth?
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1. myofacial.
2. sinus, nasal , mucosal 3. neurovascular (migraines , tension, cluster) 4. neuropathic pain disorder (neuralgia,neuroma,nueritis, neuropathy) 5. cardiac sources 6. psychogenic |
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what are the nerve fibers that supply the dentin-pulp complex?
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A fibers (delta/beta)
C fibers |
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what are the A fibers responsible for?
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cold stimulus and sharp pain
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what are C fibers responsible for?
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dull aching pain and referred pain
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what fibers respond to the hydrodynamic effect?
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A fibers.
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cell bodies of the sensory neurons of the pulp are in the _________ ganglion
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trigeminal
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How does thermal testing get a response?
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outward (cold) and inward (hot) movement of dentinal fluid
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how does EPT get a response?
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ionic movement
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A patient reacts to stimuli and says it causes discomfort but reverses quickly after the stimulus removed. What are you thinking?
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reversible pulpitis
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what else would u expect?
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response to cold and heat
often no rx manifestations |
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a px has intermittent spontaneous pain with heightened prolonged episodes of pain after the source is removed. There is a severe response to cold . What are u thinking?
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irreversible pulpitis
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what is the etiology of pulpitis?
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caries, trauma, defective resto.
*usually no rx manifestations |
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what can cause a delayed response to cold?
|
calcified canals
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what indicates you have unroofed the pulp horns?
|
color and depth
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what should you remember about the maxillary molar palatal root?
|
-easiest to access
-curving back to u! be careful |
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what is parallel to the access of MB1 and MB2?
|
the marginal ridge of the max first molar
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why is the maxillary first molar often retreated?
|
missed MB2 which is the smallest canal on tooth
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what is more variable the max first or second molar?
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second.
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it is common because of the improper angulation of the operators bur to take way to much tooth structure off what part of the access prep for the second max molar?
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the distal
*this is important, bc in reality there should be more taken from the mesial . So reorient closer to marginal ridge |
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what word do you need to use when explaining EPT testing to a patient?
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PAIN
-"please tell me when you feel "pain" in ur tooth" |
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where must you apply EPT?
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tooth structure
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does a periapical lesion always mean infected tooth?
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no
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EPT and cold testing does not work on _____
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porcelien
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what must u rely on then?
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palpation and percussion and radiographs
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some causes for reversible pulpitis?
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recent resto
dental caries hyperocclusive tooth cutting dry |
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what do we do for reversible pulpitis?
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preserve the pulp and allow tertiary dentin to form
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what are a few steps you can take to make sure the patient leaves with a successful treatment?
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thorough examination to determine which tooth is symptomatic, always consider referred pain.
-the tooth that is to be RCT'd should be taken down occlusally if it hits first when the px bites down. Or that root canal will hurt alot. |
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is there an EPT response in peri apical inflammatory disease?
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no
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what is the general shape of maxillary molar access prep?
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-trapezoidal or triangular outline
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if the palatal root is angled buccaly, what will you see on rx?
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a radiodensity
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the DB canal of max first molar has?
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distal dilaceration
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>80% of max first molars have _____ canals
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4
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describe canal obturation of the max first molar
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obturate the largest canal (palatal) first and form the master cone and accessory cone. Follow with the DB canal with a formed master cone and accessory. If room permits, try one of the mesial canals (MB 1 or MB2)
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what if there is no room to do the mesial buccal canals (MB1 or MB2)!??
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take ur trial cone film for palatal and DB canals, then obturate the MB1 and MB2 after and take a separate trial cone shot. SO you will have two rx for this
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if you need to adjust GP in the canal, what can u do?
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GP can be removed with a Hedstrome file (30 or 40). twist 2 to 3 times into GP and remove
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what RPM are Gates Glidden used at?
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500 RPM
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are GG drills end cutting?
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no they r side cutting
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mueller burs
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the long latch type round burs for deeper portions of access prep
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wat tool can you use to introduce caOH paste and sealer into the prepared root canal space?
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the lentulo spiral
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half filled square?
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Flex NTK
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what sizes in the UBC endo cassette are Flex SSK files?
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15-25
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what do these files minimize?
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risk of ledging and transportation
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in curved canals that require a file over 25, what is best to use?
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not k files, u need Flex Niti
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How large is the cutting surface of K files?
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D0-D16-->16mm
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what 3 colors do not repeat with K files and are specific to the smaller files?
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6-pink
8-grey 10--purple |
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what does the number on the file indicate?
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the cross sectional diameter at the tip
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for each 1mm in length to D16, the diameter of the file increases _____mm
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.02mm
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k files can be used in what motions?
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filing and balanced force
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wat K files are safe for filing overall?
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the smaller k files (6-15). Only use the larger files if the canal is straight
*u must precurve the larger files to the canal shape |
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when you have introduced a file in balanced force technique, what do u remember to do once u have reached WL?
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a good 2-3 full circles clockwise to load any remaining debris into the flutes
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how will a hedstroem file easily break?
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if used in rotation
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use a hedstoem file that is ______ size ______ than the canal at working length.
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one size smaller
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what is their taper?
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.02
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what motion is used for these Flex NTK files?
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balanced force technique
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what are the different rotary instruments available?
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SX protaper file
Profile Vortex files |
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which rotary files have .04 taper and are available in size 20-40 and lengths 21 and 25?
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profile vortex
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what is the file setting in RPM for SX protaper file?
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300 RPM
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what speed in RPM is the profile Vortex file used?
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500-600 RPM
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what instrument has two different ends: one to place a temp filling and the other to sear off extra GP?
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Glick #1
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specialized pliers used for retrieval of small materials from the canal
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Steiglitz pliers
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what is gutta percha?
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75% zinc oxide
20% gutta percha other materials such as opquers and coloring agents |
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what is ROTH sealer?
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a zinc oxide and eugenol mixture
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what is thermaseal (AH+)
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an epoxy resin based sealer
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max lateral incisor
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dilaceration
dens invaginatus lingual radicular groove |
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max canine
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dilaceration
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max first premolar
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2 roots and 2 canals (usually)
concavities on M and D fine root tips (careful of perf) |
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max second premolar
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single root
distally curved two canals in single root that often unite |
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max first molar
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1-3 roots
2-4 canals mesial pulp chamber |
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mand central incisor
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80% one canal but if 2 they often join
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mand 2nd incisor
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distal dilaceration
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mand canine
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2 canals in one root in 20%
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mand first premolar
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usually 1 canal
bend instrument to find 2nd canal lingually look for disappearing shadow on rx. "fast break" |
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mand second premolar
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usually one canal
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mand first molar
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3-4 canals (2 in mesial root and 1 in distal)
distal canal can curve at 90 degrees distally curved mesial canals |
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mand second molar
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susceptible to vertical root fractures
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the key that facilitates biomechanical preparation and obturation
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access preparation
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4 objectives of access preparation
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1. unroof pulp chamber
2. remove pulp horns 3. straight line access to apical third 4. conserve tooth structure |
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why remove pulp horns?
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prevents staining of clinical crown
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when is it necessary to remove existing restos on ur endo tooth?
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recurrent caries
thin portion susceptible to breakage after access prep hampers visualization |
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once you have confirmed pulp chamber entrance with the DG16 what should u do?
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irrigate chamber
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what governs outline form?
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pulp chamber anatomy and straight line access to apex
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how do u confirm complete removal of pulp chamber roof?
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spoon excavator doesnt catch
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explain obtaining straight line access in anteriors
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remove the lingual islands with safe ended or round latch bur. GG drills to modify lingual wall
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floor of pulp chamber is usually _____ in color
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greyish
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how does the access prep differ between max and mand molars?
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max molars have their widest dimension B-L
mand molars have their widest dimension MD |
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6 errors in access preparation?
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1. missed canals
2. constricted access prep 3. pulp horns not included 4. failure to unroof chamber 5. overextended access prep 6. access prep perforation |
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what are the most common missed canals?
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1. MB2
2. 2nd distal canal in mandibular molars 3. lower incisors second canal 4. birfurcated canals in lower premolars 5. third canals in upper premolars |
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how can u prevent failure to unroof pulp chamber?
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properly examine rx and measure the distance to the floor of the pulp chamber
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where should a canal ideally terminate?
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the CDJ which is situated .75 mm inside the apical foramen-->the apical constriction
*.5-1mm short of the rx apex |
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if u look at the PWL rx and u notice that your 22mm file is poking 1mm out the end of the apex, what do u do?
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subtract the 1mm then subtract another 1mm so that your next file is 20 mm . The 20mm file should be larger. take a radiograph
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if you take a mesial angulated rx of a lower anterior and notice the file is not in the central axis of the tooth, what should u be thinking?
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an additional canal !!
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the Root ZX apex locator emits currents at frequencies of _____ and _____ kHz?
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8 and .4
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4 parts of an apex locator
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device
file clip lip clip 2 cords (lip clip and file clip connections) |
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this part of endo treatment includes intrumentation and irrigation
|
biomechanical preparation
"cleaning and shaping" |
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what motions of filing satisfy this phase of tx?
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reaming and filing
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3 objectives to biomechanical prep?
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1. to clean
2. to shape 3. to create an apical matrix to prevent extrusion of material and supply a barrier to condense GP |
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u should treat the easiest canal first in multirooted teeth. This means wat for the Max bicuspid and molar?
|
bucuspid-palatal then buccal
molar-palatal, DB MB MB2 |
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what canal is easiest for mand molar?
|
distal then mesial
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how do strip root perforations occur?
|
over instrumentation of DANGER ZONES where thin dentin walls exist between pulpal space and external.
these zones need very minimal instrumentation |
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bicuspids often have concave external root surfaces. How will this affect instrumentation?
|
hour glass figure. not round. Treat as if 2 canals are present so instrument buccal and lingual more than the center
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the MB root of max molars often have kidney shape with concave distal aspect of root. How will this affect istrumentation?
|
Keep away from the distal aspect of root canal
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the mandibular molar has a concavity on the distal of mesial root and mesial of distal root. So where are the danger zones?
|
instrumentation needs to be confined to walls away from the furcation.
|
|
|
debridement
|
instrumentation and irrigation
|
|
|
instrumentation
|
planing all walls to loosen debris
|
|
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irrigation
|
flushing debris from root canal
|
|
|
irrigation is performed
|
between all instrument changes
|
|
|
after each step back file?
|
recapitulate with MAF
|
|
|
what file must advance before GG drills for coronal prep?
|
#35
|
|
|
what are some advantages of crown down technique?
|
-easier access
-time saving with rotary Niti -better distribution of irrigating solutiom -better removing of canal contents -straight and curved canals no different |
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|
what are some limitations of rotary Niti?
|
-if 2 canals join, you must instrument after the point of union
-only use rotary to the first curve of double curved canals -cannot follow 90 degree curves |
|
|
How do you prepare the coronal portion of the canal with the crown down technique?
|
after the WL rx, take a protaper SX file on an MM 324 hand piece at 300 RPM and start flaring the coronal portion. Insert it until resistance then withdraw .5 mm twice . clean the file and irrigate
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|
|
how do u prepare the apical half of the root canal in the crown down technique?
|
-make sure the canal is irrigated, then use the 40 Profile Vortex file and proceed until resistance is felt then proceed 1mm, then withdraw .5mm then try to advance another 1mm then completely withdraw.
-repeat this step -work your way from #35 next, 30, 25 -if you do not reach full working length with 25, use 20 -size up the apex -MAF |
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what color is the 40 Profile ?
|
black
|
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what speed do u use it ?
|
full speed on handpiece
|
|
|
should u stop the file rotating?
|
no , never. always keep it spinning in the canal and in movement
|
|
|
should u force it 1mm ?
|
never force it.
|
|
|
what is "sizing up the apex"?
|
match the size of the apex to the size of a hand file. the file must engage the apical 1/3 of the canal and when it does, give it 1/4 turn clockwise to engage the debris and remove it. Start with the size of the profile that went to WL. (20 or 25).
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|
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When would you use the hybrid technique?
|
-on large canals like the distal canal in mandibular molars or the palatal canal in max molars. This is bc you cannot achieve the taper you need with just the profile vortex bc the #40 may very well go to WL.
-you need stepback technique too! |
|
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After u have completed the crown down portion of the Hybrid technique, you size up the apex with the same size Niti hand file. Its binds and is size 40. what is next for the MAF and step back technique needed to complete the hybrid?
|
-You instrument with the next file size up which will be you MAF, so 45.
-now step back with 50 55 60 70 80 *recapitulate and irrigate between each |
|
|
what are the 3 criteria for determining an end point to cleaning?
|
1. glassy , smooth walls
2. clean dentin shavings 3. clean irrigating solution |
|
|
the 2 criteria for determining the end point to shaping
|
-adequate prep of apical matrix so that an instrument 3 sizes bigger than the first to bind at WL has made the matrix.
-sufficient flare, so that spreaders can get down to within 1-2 mm from WL after mastercone fitted. |
|
|
4 errors i instrumentation
|
-ledge formation
-root perforations -broken instruments -canal blockage |
|
|
endo retreatment indications
|
-persistant apical periodontitis for >2 yrs
-recurrent symptoms -recurring sinus tract -coronal leakage -missed canal -inadequate obturation when new coronal resto is planned |
|
|
how can u tell if silver cones are used for root canal obturation rather than GP?
|
on the rx, you will see more radiodense than GP and there will be no taper like GP
|
|
|
why is an advantage of a semisolid material such as GP?
|
the ability to retrieve them ! (ex. retreatment)
|
|
|
if a treated tooth has a PA lesion , does this mean retreatment?
|
it DEPENDS. if the tooth has no symptoms and no sinus tract, the ligament space is intact and there is perfect lamina dura then treatment is TO OBSERVE.
|
|
|
if you have "eyes" when you open up a RCT for retreatment what does this mean?
|
it means that there was Gutta Core used (carrier based obturation) and it is not removed with heat or chloroform so u must use rotary or reciprocating NiTi files
|
|
|
How do you retreat a thermafil obturation
|
thermafil is a plastic carrier GP.
-use protaper D1/D2 to mid root then add chloroform dropwise into canal -Protaper D3 or Profile 30/04 using apex locator to gauge WL -us hoedstroem files to remove plastic carrier -K files to negotiate WL |
