Instrumentation of the Root Canal System Flashcards
what is the purpose of instrumentation
- Remove infected soft and hard tissue
- Give disinfecting irrigants access to apical canal space
- Create space for the delivery of medicaments and subsequent obturation
- Retain the integrity of radicular structures
what is the purpose of instrumentation
- Remove infected soft and hard tissue
- Give disinfecting irrigants access to apical canal space
- Create space for the delivery of medicaments and subsequent obturation
- Retain the integrity of radicular structures
what is the purpose of keeping the apical opening as small as possible
○ Over enlarging it allows for extrusion of materials into the apical tissues
○ If hypochlorite gets into the tissues it can have serious consequences for your patient
○ Also affects the long term prognosis of the tooth as it makes it harder to obturate it as it is more difficult to obtain an apical seal to maintain a sealer within the tooth
what are the design objectives of a root canal space
- Create a continuously tapering funnel shape
- Maintain apical foramen in original position
- Keep apical opening as small as possible
what is the purpose of keeping the apical opening as small as possible
○ Over enlarging it allows for extrusion of materials into the apical tissues
○ If hypochlorite gets into the tissues it can have serious consequences for your patient
○ Also affects the long term prognosis of the tooth as it makes it harder to obturate it as it is more difficult to obtain an apical seal to maintain a sealer within the tooth
what is the purpose of chemomechanical preparation
• Chemo
○ Irrigate to kill micro-organisms
○ Remove smear layer
• Mechanical
○ Prepare shape
○ Flush out debris and micro-organisms
what is the aim of mechanical preparation
- Shape the canal
- Allows delivery of sodium hypochlorite to working length
- Creates shape to obturate
name some challenges to root canal preparation
• The root canal system is very complex
○ Difficult to get sodium hypochlorite to penetrate all the smaller / lateral / accessory canals
- The number, length, curvature and diameter of canals can vary considerably
- Teeth are weird
what size of apical diameter to you want and why
an apical diameter of ISO 25 (0.25mm) or ISO 30 (0.3mm) in order to deliver the syringe and the irrigant it contains into the apical portion of the tooth, to try and get some penetration into the little lateral canals
define estimated working length
and how is it got
Estimated length at which instrumentation should be limited
Obtained by measuring pre-operative radiograph to determine distance between coronal reference point and radiographic apex then subtracting 1mm
define corrected working length
and how is it got
Length at which instrumentation and subsequent obturation should be limited
Obtained by the use of an electronic apex locator and / or working length radiograph
Confirmation of the estimated working length
what is the master apical file
The largest diameter file taken to working length and therefore represents the final prepared size of the apical portion of the canal at the working length
what are the different types of motion
- Filing
- Reaming (warning)
- Watch-winding
- Balance forced motion
- Envelope of motion
explain what is meant by watching winding motion and when are they used
- Back and forward oscillation of 30-60 degrees
- Light apical pressure
- Effective with K files
Useful for passing small files through canals
explain the balanced force technique
- insert file and engage clockwise into the dentine, 1/4 turn (90 degrees)
- with continued pressure, go counter clockwise 1/2 (180 degrees) turn to strip the dentine away
- do this 1 to 3 times before removing the file to remove debris and check the file
- then reintroduce the file to the canal and repeat until working length
explain the envelop of motion
honestly no clue lol sorry fix this if yous know the answer but my notes is legit just a picture of a file with arrows that i dont understand but feel free to look that up hehe
what is the barbed broach instrument
when is it used
what are the negatives to it
how is it used
- Used for extirpating, not enlarging - can be useful for lifting bits of debris or cotton wool from a canal
- Formed from a tapered round shaft by lifting up portions of metal of the shaft almost at a right angle to the shaft
- Must not engage the canal walls
- Extremely fragile instrument, and will break easily if misused
- Not used very often
- Elevated barbs engage the pulp tissue and remove it from the canal
- The largest size broach that will fit freely in the canal is selected
after shaping is complete, what is the irrigation protocol
• EDTA 17% for 1 minute
○ To remove the smear layer
• Sodium hypochlorite 3%, 30ml for 10minutes
Slow injection, don’t use thumb
what is the barbed broach instrument
when is it used
what are the negatives to it
how is it used
• Used for extirpating, not enlarging - can be useful for lifting bits of debris or cotton wool from a canal
• Formed from a tapered round shaft by lifting up portions of metal of the shaft almost at a right angle to the shaft
• Must not engage the canal walls
• Extremely fragile instrument, and will break easily if misused
• Not used very often
• Elevated barbs engage the pulp tissue and remove it from the canal
The largest size broach that will fit freely in the canal is selected
what are the ISO colour codes
06 - pink 08 - grey 10 - puple 15 - white 20 - yellow 25 - red 30 - blue 35 - green 40 - black 45 - white 50 - yellow 55 - red 60 - blue 70 - green 80 - black
ISO 35 file has a tip size of what
0.35 mm
what are stainless steel instruments
when are they used
explain the diameters
• ISO-sized instruments
○ All have 16mm cutting flutes
○ Each file is named according to its diameter at the first rake angle [tip] - D1
○ Taper is 0.32 over the 16mm / 0.02 per millimetre
○ Diameter at D2 = apical size + 0.32mm
what is the cross section of K-reamers
triangular
what is the cross section of K files
square
