Restoration of extensively damaged vital teeth

Question 1

Pulp and — mm thick surrounding layer of dentin
should be preserved if possible

Answer 1

1

Question 2

Retentive features should not be cut deeper than
— at cervical line or central fossa (—)

Answer 2

1.5mm
2mm

Question 3

Auxiliary retentive features ideally kept in “—
zone”

Answer 3

safe

Question 4

Caries removal: deeper areas filled with

Answer 4

base

Question 5

Restoration of extensively damaged vital teeth
-Central Core Guidelines Central Core (Pulp Chamber) (2) as we age

Answer 5

shrinks and recedes

Question 6

5 Categories involved in decision making:

Answer 6

-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

Question 7

Restoration of extensively damaged vital teeth
-Restoration selection
To determine the type of restoration to use when large decay has destroyed tooth structure:
(5)

Answer 7

Where is the decay?
How much tooth structure is remaining?
Where is the remaining tooth structure?
Can I restore this?
Should I restore this?

Question 8

Isthmus destruction greater than ½
intercuspal width –

Answer 8

Crown or Onlay

Question 9

More that 50% of tooth structure is gone
and loss of cuspal suport–

Answer 9

Crown (and
likely a core build up too)

Question 10

Restoration of extensively damaged vital teeth
-Restoration selection
Combined Central and Peripheral destruction:
(2)

Answer 10

-Core Build up and Crown
-Possible RCT/Post/Core/Crown

Question 11

When would you decide you needed
Root Canal Treatment?
(2)

Answer 11

If pulp is exposed
If post is needed for retention of
Build up

Question 12

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)

Answer 12

Re-orientation of sloping surfaces
Adding Grooves
Adding Box forms
Adding Pins with a Build up

Question 13

*There are also times when leaving a crown
preparation without a Build up can help with
retention too. Sometimes,

Answer 13

you need to leave it
ugly.

Question 14

What can we do to increase resistance form with less than ideal tooth structure
remaining?
(4)

Answer 14

-Reshape axial walls to reduce convergence
-Add grooves
-Add Box forms
-Increase wall height

Question 15

-Increase wall height
(4)

Answer 15

-place finish line more apical
-Pin retained core
-Crown-lengthening
-Orthodontic extrusion

Question 16

Reshape axial walls to reduce convergence
Increased axial reduction in the cervical 1/2 of the preparation wall will

Answer 16

reduce taper and create more retention and greater resistance form.

Question 17

Restoration of extensively damaged vital teeth
-Retention – Sloped wall
Incorrect
Sloping surfaces left after cusp fracture or caries
removal need retention
(2)

Answer 17

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.

Question 18

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 –

Answer 18

-A facial shoulder with axial wall reduction leaves
adequate wall length for resistance form.

Question 19

Restoration of extensively damaged vital teeth
-Retention - Grooves
-Grooves placed parallel to the long axis of the tooth
(3)

Answer 19

-at least 1mm wide and deep
-0.5 to 1mm away from the finish line
-Spaced around the tooth

Question 20

Restoration of extensively damaged vital teeth
-Retention - Grooves
Grooves used in short preparation walls
with minimal occlusal clearance:
(2)

Answer 20

-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

Question 21

Restoration of extensively damaged vital teeth
-Retention – Box form
Box form can be used for retention
(4)

Answer 21

-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

Question 22

Restoration of extensively damaged vital teeth
-Retention – Box form
When two boxes are needed, less than 180 degrees of tooth
circumference remains.
(2)

Answer 22

-This poses a great risk for cuspal fracture
-Use a Build Up and full crown to protect against fracture

Question 23

Restoration of extensively damaged vital teeth
-Retention – Sloping, Box form and Grooves
(6)

Answer 23

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

Question 24

Restoration of extensively damaged vital teeth
-Retention – Wall height
How can we get more Wall height?
(4)

Answer 24

-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.

Question 25

Core Build up (3)

Answer 25

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

Question 26

Build Up is needed when more than --% of the tooth structure is lost Insurance companies add – a Build Up is needed for --- of a crown.

Answer 26

50 retention

Question 27

Build up Guidelines- (2)

Answer 27

First reason for Build up – Short axial walls Second reason for a Build up – Excessive interocclusal distance (tall crown height)

Question 28

Amalgam Core Build Up

Answer 28

Not retentive, but strong

Question 29

Composite Resin materials

Answer 29

Retentive, but not as strong

Question 30

Use of pins recommended if

Answer 30

½ or more of the clinical crown has been destroyed.

Question 31

Cusps thinner than ½ their height are

Answer 31

weak and should either be shortened or removed.

Question 32

For amalgam core, the cavity floors and walls should be ---.

Answer 32

flattened

Question 33

Crown margins should be at minimum -- mm apical to build up material margin.

Answer 33

1

Question 34

Amalgam Core Mechanical properties (2)

Answer 34

Compressive strength Dimensional stability

Question 35

Amalgam Core --- less technique sensitive

Answer 35

Isolation

Question 36

Amalgam Core Matrix placement can be difficult if tooth is severely

Answer 36

broken down.

Question 37

Amalgam Core Often used in RCT teeth into canal for ---

Answer 37

strength

Question 38

Amalgam Core Limitations: (7)

Answer 38

Matrix placement can be difficult if tooth is severely broken down Slow setting material (10-15 minutes before band removal) No bonding or natural retention Requires at least 2mm thickness Color shows through some ceramic crowns Final crown prep occurs another day Not used to a great extent any longer.

Question 39

Composite Core (5)

Answer 39

Mechanical properties Bonds to tooth structure Still needs help with pins Quick setting Tooth prep at same visit Ease of manipulation Can be thinner than 2mm Color of material aids in crown matching

Question 40

Composite Core Limitations (3)

Answer 40

Technique sensitive Microleakage possible as material shrinks when cured Isolation can be challenging

Question 41

Build Up Guideline - (2)

Answer 41

Crown margin (finish line) needs to be on sound tooth structure or life of crown restoration is compromised. Rule is rarely broken, but some science suggests it is possible to for this to occur successfully.

Question 42

Pins are helpful to support the Build Up material when residual tooth structure

Answer 42

does not provide adequate retention itself.

Question 43

Pins increase resistance for --- The resistance is both (2) Pins should be placed ---

Answer 43

Build up support internally and apically non-parallel

Question 44

Guidelines for Pin placement (3)

Answer 44

-Place in sound, healthy dentin -Do not damage or undermine nearby enamel -Angulation can create problems. Avoid perforations or pins into the pulp!

Question 45

-Place in sound, healthy dentin (1)

Answer 45

-If the dentin is not sound, the threaded pin will not “bite” and will just spin in the hole and/or fall out

Question 46

-Do not damage or undermine nearby enamel (3)

Answer 46

-Flat area of placement -0.5 to 1mm from DEJ or axial wall -at least 0.5 mm of dentin should surround the pin

Question 47

Pins introduce dentin stresses creating --- Also introduces --- around the pin --- dentin is a must!

Answer 47

micro fractures microleakage Solid

Question 48

Guidelines for Pin placement -Best used in --- of posterior teeth to avoid furcations, perforations and the pulp! -1 pin per (3) -At least --- of space between pins -Max of --- pins per tooth

Answer 48

line angles missing cusp, line angle, or axial wall 5mm 4

Question 49

Pin Placement Procedure

Answer 49

-Use Pilot drill to make pilot hole. Depth gauge is on the drill! -Used with slow speed hand piece -Watch angulation and position -Using Filpin latch pin and slow speed handpiece, place pin just in hole, then full rheostat power. -The pin will snap off at the area of the shaft that has been scored. -The teeth of the pin should “bite” in the dentin. -The pin should not be mobile or able to be easily pulled out. -If the pin is mobile or pulled out, the dentin is either still decayed or too soft to support a pin (can be the case in RCT teeth). Pins often then need to be bent to help create non-parallelism and to create even more retention This instrument can be used to bend the pins Pin should remain in dentin during bending

Question 50

Pins placed into dentin should: -Be -- mm deep into dentin -Be -- mm coronal into Build up -Minimum -- mm radius of Build up still around pin after preparation is done

Answer 50

2 2 1

Question 51

Drills have a (2)

Answer 51

cutting tip and helical flutes

Question 52

Drill down in one motion without

Answer 52

additional movement to create a tight perfect pilot hole for the pin.

Question 53

Too much wobble or imperfect handpiece technique creates a

Answer 53

pilot hole that is too wide for the pin threads to properly bind into.

Question 54

Once the pins are placed and bent if necessary, a --- is placed around the prep

Answer 54

matrix Then Build up can be placed using techniques required of them Matrix is removed and now crown prep can proceed as normal

Question 55

Pin Complications-Pin into pulp – -Pin exits tooth surface above bone – -Stripped pin (threads don’t bite) –

Answer 55

RCT needed flap and smooth to tooth contour move to another location at least 1.5 mm away or use a larger sized pin

Question 56

Bases Bases are used only to protect pulp in teeth that are have ---

Answer 56

excavations that are deep and near the pulp.

Question 57

Bases can be used to fill in --- when an entire Build up is not needed.

Answer 57

undercuts

Question 58

Bases are weaker materials that do not provide strength like a

Answer 58

Build up.

Question 59

Bases are not strong enough to support (3)

Answer 59

grooves, boxes or other retentive features.

Question 60

Base – material that protects the pulp. Common Protocol: (5)

Answer 60

1. Gluma (Gluteraldehyde) -2x60 second coats 2. Dycal / Calcium Hydroxide 3. Vitrebond 4. Glass Ionomer? 5. Routine restoration steps

Question 61

Restoration of extensively damaged vital teeth -Sequence of Treatment *Prior to prep: (2)

Answer 61

-Evaluate periodontal and endodontic health -If non-vital, RCT is needed

Question 62

*Remove all caries. Often, but not always, you will remove any prior materials like old restorations or previous bases.

Answer 62

**You may not need to remove all caries. If you determine that the tooth is non-restorable, you may not need to excavate everything prior to extraction or RCT. Case by case basis with Faculty.

Question 63

Re-evaluate your prep. (4)

Answer 63

-HOW MUCH TOOTH STRUCTURE IS REMAINING?? -Is there enough tooth to restore this tooth well? -Can the defects made from caries removal be incorporated into prep for retention? -Do you need a Build Up? or Base? or Pins? or a Post?