Restoration of extensively damaged vital teeth Flashcards
Pulp and — mm thick surrounding layer of dentin
should be preserved if possible
1
Retentive features should not be cut deeper than
— at cervical line or central fossa (—)
1.5mm
2mm
Auxiliary retentive features ideally kept in “—
zone”
safe
Caries removal: deeper areas filled with
base
Restoration of extensively damaged vital teeth
-Central Core Guidelines Central Core (Pulp Chamber) (2) as we age
shrinks and recedes
5 Categories involved in decision making:
-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
Restoration of extensively damaged vital teeth
-Restoration selection
To determine the type of restoration to use when large decay has destroyed tooth structure:
(5)
Where is the decay?
How much tooth structure is remaining?
Where is the remaining tooth structure?
Can I restore this?
Should I restore this?
Isthmus destruction greater than ½
intercuspal width –
Crown or Onlay
More that 50% of tooth structure is gone
and loss of cuspal suport–
Crown (and
likely a core build up too)
Restoration of extensively damaged vital teeth
-Restoration selection
Combined Central and Peripheral destruction:
(2)
-Core Build up and Crown
-Possible RCT/Post/Core/Crown
When would you decide you needed
Root Canal Treatment?
(2)
If pulp is exposed
If post is needed for retention of
Build up
Restoration of extensively damaged vital teeth
-Retention
Often, a tooth preparation will need to be modified
by adding retentive features to increase retention
and improve the resistance form:
(4)
Re-orientation of sloping surfaces
Adding Grooves
Adding Box forms
Adding Pins with a Build up
*There are also times when leaving a crown
preparation without a Build up can help with
retention too. Sometimes,
you need to leave it
ugly.
What can we do to increase resistance form with less than ideal tooth structure
remaining?
(4)
-Reshape axial walls to reduce convergence
-Add grooves
-Add Box forms
-Increase wall height
-Increase wall height
(4)
-place finish line more apical
-Pin retained core
-Crown-lengthening
-Orthodontic extrusion
Reshape axial walls to reduce convergence
Increased axial reduction in the cervical 1/2 of the preparation wall will
reduce taper and create more retention and greater resistance form.
Restoration of extensively damaged vital teeth
-Retention – Sloped wall
Incorrect
Sloping surfaces left after cusp fracture or caries
removal need retention
(2)
Break slope into vertical and horizontal
components
Conversion into one large vertical wall
weakens tooth with too much removal
and endangers the vital core of the
tooth.
Restoration of extensively damaged vital teeth
-Retention – Sloped wall
Sloping surfaces left after cusp fracture or caries
removal need retention
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.
Restoration of extensively damaged vital teeth
-Retention - Grooves
-Grooves placed parallel to the long axis of the tooth
(3)
-at least 1mm wide and deep
-0.5 to 1mm away from the finish line
-Spaced around the tooth
Restoration of extensively damaged vital teeth
-Retention - Grooves
Grooves used in short preparation walls
with minimal occlusal clearance:
(2)
-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
Restoration of extensively damaged vital teeth
-Retention – Box form
Box form can be used for retention
(4)
-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
Restoration of extensively damaged vital teeth
-Retention – Box form
When two boxes are needed, less than 180 degrees of tooth
circumference remains.
(2)
-This poses a great risk for cuspal fracture
-Use a Build Up and full crown to protect against fracture
Restoration of extensively damaged vital teeth
-Retention – Sloping, Box form and Grooves
(6)
Sloping walls
Converging walls
Short wall height
Occlusal forces
Amalgam removed
Boxes and grooves placed
Axial walls prepared in apical ½ to reduce converging walls
Restoration of extensively damaged vital teeth
-Retention – Wall height
How can we get more Wall height?
(4)
-Place margin more apically. Often this is
below the gingiva. However, we must avoid
breaking into biological width.
-Add materials to “Build Up” the tooth. 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.
-Remove biological width restriction with
crown lengthening.
-Pull the tooth out of the bone with
orthodontic extrusion.
Core Build up
(3)
Replaces lost tooth structure to improve
retention of a crown
A core must be anchored firmly to the tooth
and not just placed to fill the void
Retention for a core is often with the use of
pins