Restoration of extensively damaged vital teeth Flashcards
What is the central core concept guidelines?
- Pulp and 1 mm thick surrounding layer of dentin should be preserved
- Retentive features should not be cut deeper than 1.5mm at cervical line or central fossa (2mm)
- Auxiliary retentive features ideally kept in “safe zone”
- Caries removal: deeper areas filled with base
Pulp and ___ mm thick surrounding layer of dentin should be preserved if possible
1
Retentive features should not be cut deeper than ____mm at cervical line or central fossa
1.5
- central fossa more like 2 mm
Caries removal on a crown prep: deeper areas filled with ____
base
Avoid excessive tooth removal in the name of __________!
retention
Central Core (Pulp Chamber) shrinks and recedes…
as we age
What are the 5 categories involved in decision making for extensively damaged vital teeth?
-Deciding on the type of restoration to use (Crown, Filling, or other)
-Using defects as retentive features (Do I need a build up?)
-Pin placement and retention (Will a build up stay put?)
-Bases and Cores (Do I need to protect the pulp?)
-Tooth preparation procedures
To determine the type of restoration to use when large decay has destroyed tooth structure what questions do we need to ask?
- Where is the decay?
- How much tooth structure is remaining?
- Where is the remaining tooth structure?
- Can I restore this?
- Should I restore this?
What is restoration selection?
Determine if a filling or a crown is needed
If there is extensive peripheral destruction what restoration do you do?
Full Crown
If there is extensive central destruction greater than 1/2 intercuspal width: what restoration?
Crown or onlay
If there is extensive central destruction that is more than 50% of tooth structure and loss of cuspal support: what restoration?
Crown (and likely a core build up too)
If there is combined central and peripheral destruction what do you do?
-Core Build up and Crown
-Possible RCT/Post/Core/Crown
When would you decide you needed
Root Canal Treatment?
- If pulp is exposed
- If post is needed for retention of Build up
What ways can you add retentive features to increase retention and improve resistance form?
- Re-orientation of sloping surfaces
- Adding Grooves
- Adding Box forms
- Adding Pins with a Build up
T/F: Sometimes it is ok to leave a crown preparation without a build up and leave it ugly.
True! It can help with resistance and retention
What can we do to increase resistance form with less than ideal tooth structure remaining?
-Reshape axial walls to reduce convergence
-Add grooves
-Add Box forms
-Increase wall height
What are ways to increase the wall height of a crown prep?
-place finish line more apical
-Pin retained core
-Crown-lengthening
-Orthodontic extrusion
Increased axial reduction in the cervical 1/2 of the preparation wall will…
reduce taper and create more retention and greater resistance form
________ surfaces left after cusp fracture or caries removal need retention
Sloping
How do you change a sloping surface to add retention?
Break slope into vertical and horizontal components
- do not change into one large vertical wall because it weakens tooth and endangers vital core
What should you do if greater than 3mm of vertical wall length is apical to the fractured cusp?
A facial shoulder with axial wall reduction leaves adequate wall length for resistance form
Grooves placed _______ to the long axis of the tooth
parallel
Grooves are at least ___mm wide and deep
1 mm
Grooves are placed ______ mm away from the finish line
0.5-1.0
Grooves used in short preparation walls with minimal occlusal clearance do what…
-Proximal grooves shorten the radius of the arc of rotation
-Walls of a groove or a box are best placed perpendicular to the displacing force
Box forms can be used for retention in what cases?
-Remove caries
-Convert caries removal into a box form by squaring walls
-Not needed on intact walls
-Box should be well into dentin (deep enough) to resist displacing forces
When two boxes are needed, less than 180 degrees of tooth circumference remains; why is this a problem?
-This poses a great risk for cuspal fracture
-Use a Build Up and full crown to protect against fracture
When increasing the wall height by placing the finish line more apically what do you need to watch out for?
breaking into biological width
What is important to know about a build up?
Core build up can give more wall. Remember, the finish line needs to be on tooth structure and you still need at minimum 2-3mm of ferrel.