Post and Cores Flashcards
What things to check for when assessing whether a RCT’d tooth has been successful?
Lack of symptoms
No pain
Not TTP
No palpation pain
No swelling
Radiographic healing
Functional and aestehtic tooth
Describe radiographically a failed RCT?
Presence of a periradicular radiolucency, unchaned or a new increased rarefraction
When does a RCT’d tooth new re-reatment?
If the GP has been exposed in the mouht for some time
OR
if post-treatment disease has been diagnosed
What factors dictate whether a tooth has a good prosthodontic prognosis?
The quality and quantity of remaining tooth structure is the single most important factor
What to assess in the root filled tooth?
Remove all caries, restorations and assess the quatity distribution and quality of tooth substance remaining
What is the ferrule’s effect?
The remaining coronal tooth tissue offers retention, resistance and a substrate to bond to
What is the defintion of the ferrule?
A metal ring or cap intended to embrace the tooth structure cervically to achieve root strengthing and prevent shattering of the root
2mm H
1mm W (from post hole to margin)
What factors influence the ferrule?
A longer ferrule increases fracture resisatnce significantly
Also resists lateral focres from the posts and leverage from the crown in function
It increases retention and resistance of the restoration
Name the 5 requirements for a successful crown/crown prep?
Ferrule (dentine axial wall height) must be at least 2-3mm
The axial walls must be paralled
Restoration must encircle tooth
Margin is on solid tooth structure
Corwn and prep must not invade the biologic width
What are the clinical complications for missing 1 of the 5 requeirements of the prep?
Root Fracture
Coronal apical leakage
Reccurent caries
Dislodgement or loss of the core
Perio injury - LoA, recession, and bone loss - biologic width invasion
What are the 4 advantages for the Ferrule effect?
Provides anti-rotational features
Increases longevity of post and core
Failure of restoration tends to be retrievable
Increases the fracture resistance of the RCT’d teeth
Is GP antimicrobial?
No
How to remove sealer from pulp chamber?
Alcohol
How to seal the pulp chamber?
Vitrebond - RMGIC
When should we place the post?
Immediately after the prep
WHat are the advantages of placing the post immediateyl?
Familiarity with RCS and WL
Decreased risk of perfs or excessive GP removal
Does NOT disrupt the apical seal
Delayed post space prep does decrease chance of coronal leakage
How does length of post influence success of RCT’d tooth restoration?
More important than width
The longer the post, the better the retention
Siginificant increase in clinical success if longer than the crown height
Shorter posts have poor retention and transmit lateral forces to the remaining root structure compared to longer posts
Need for >4-5mm of GP apically
What is the ideal width of the post?
Adequate width important for post strength and resistance to fracture
Optimum is <1mm width at the tip
but consider root morphology - larger roots can perforate the tooth
Diameter of the post at its tip should be <1/3 of the diameter of the root at the corrsponding depth e.g. lower incisor .6 and upper incisor 1mm
What are the risks of a wider post?
Increased risk of root perf
Increased cervical stresses
Decreased impact resistance
Decreased resistance to root fracture
Explain how to remove the GP for a post?
Chemical - increased apical leakage
Thermal - can distub apical GP
Mechanical - most efficient
GG (Gates Glidden) do not causes the large increases in temperature
Hand or rotary removal of GP?
Hand less change of iatro and temo
Rotary greater change of iatro and temo - high torque and low speed
Explain the process to remove GP and prep the post hole mechanically?
Use non-end cutting bur GG
Cuts GPP preferentially than dentine walls
Then use peeso reamers/parapost reamers to finally comple the prep after GP removed (can lead to increases in temp)
What are the ideal properties for a luting cement?
Insoluble
Prevent microleakage
Adherere to radciaulr dentine - potentially reinforce root
withstand fatigiue froces well
Can risk generation microcrack can culminate in the failure of the restoration
Name 3 types of traditional luting cements?
ZPC - mechanical means no chemical
GIC - depends on resin content - can bond more to dentine
RMGIC - no indicated for posts due to hygroscopy