Restoration of extensively damaged vital teeth Flashcards by Pickle Rick

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

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

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Retentive features should not be cut deeper than ____mm at cervical line or central fossa

1.5

central fossa more like 2 mm

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Caries removal on a crown prep: deeper areas filled with ____

base

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Avoid excessive tooth removal in the name of __________!

retention

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Central Core (Pulp Chamber) shrinks and recedes…

as we age

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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

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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?

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What is restoration selection?

Determine if a filling or a crown is needed

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If there is extensive peripheral destruction what restoration do you do?

Full Crown

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If there is extensive central destruction greater than 1/2 intercuspal width: what restoration?

Crown or onlay

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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)

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If there is combined central and peripheral destruction what do you do?

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

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When would you decide you needed
Root Canal Treatment?

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

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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

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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

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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

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What are ways to increase the wall height of a crown prep?

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

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Increased axial reduction in the cervical 1/2 of the preparation wall will…

reduce taper and create more retention and greater resistance form

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________ surfaces left after cusp fracture or caries removal need retention

Sloping

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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

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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

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Grooves placed _______ to the long axis of the tooth

parallel

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Grooves are at least ___mm wide and deep

1 mm

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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.

Remove biological width restriction with ___

crown lengthening

Pull the tooth out of the bone with _____

orthodontic extrusion

What is a core build up?

- 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

A Build Up is needed when more than ___% of the tooth structure is lost

50%

What are the reasons for a build up?

- short axial walls - excessive interocclusal distance (tall crown height)

What are the differences between an amalgam core build up and a composite resin build up?

Amalgam Core Build Up - Not retentive, but strong Composite Resin materials - Retentive, but not as strong

Use of pins recommended if ___ or more of the clinical crown has been destroyed.

Cusps thinner than ____ their height are weak and should either be shortened or removed.

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

flattened

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

1.0

What are the limitations of an amalgam core build up?

- Matrix placement can be difficult if tooth is severely broken down - Slow setting material - 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

What are the mechanical properties of an amalgam core build up?

- Compressive strength - Dimensional stability

What are the characteristics of an amalgam core build up?

- Isolation less technique sensitive - Matrix placement can be difficult if tooth is severely broken down. - Often used in RCT teeth into canal for strength

What are the mechanical properties of a composite core build up?

- Bonds to tooth structure (still needs help with pins) - Quick setting (tooth prep at same visit and ease of manipulation) - Can be thinner than 2mm - Color of material aids in crown matching

What are the limitations of a composite core build up?

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

What are the main guidelines for a build up?

Crown margin (finish line) needs to be on sound tooth structure or life of crown restoration is compromised.

_____ are helpful to support the Build Up material when residual tooth structure does not provide adequate retention itself.

Pins

Pins should be placed...

non-parallel

Pins increase __________ for build up both internally and apically

resistance

What are the general guidelines for pin placement?

-Place in sound, healthy dentin -Do not damage or undermine nearby enamel ---Flat area of placement ----0.5 to 1mm from DEJ or axial wall ----at least 0.5 mm of dentin should surroundthe pin -Angulation can create problems. Avoid perforations or pins into the pulp!

What happens if you try to put a pin in not sound dentin?

the threaded pin will not “bite” and will just spin in the hole and/or fall out

A pin must be _____ mm from DEJ or axial wall

0.5-1.0 mm

A pin have at least ____mm of dentin surrounding it

0.5 mm

What is the risk of pins?

- Pins introduce dentin stresses creating micro fractures - Also introduces microleakage around the pin - Solid dentin is a must!

What are the specific guidelines for the number of pins per tooth?

-Best used in line angles of posterior teeth to avoid furcations, perforations and the pulp! -1 pin per missing cusp, line angle, oraxial wall -At least 5mm of space between pins -Max of 4 pins per tooth

There should be at least ___ mm of space between each pin

5.0

There is a max of ___ pins per tooth

___ pin(s) per missing cusp, line angle, or axial wall

Where do the pins go for a maxillary second molar?

Where do the pins go for a maxillary first molar?

Where do the pins go for a maxillary second premolar?

Where do the pins go for a maxillary first premolar?

Where do the pins go for a mandibular second molar?

Where do the pins go for a mandibular first molar?

Where do the pins go for a mandibular second premolar?

Where do the pins go for a mandibular first premolar?

What is the pin placement procedure?

-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. - Bend pins if needed to create more retention.

Pins place should be ___mm deep into dentin

2.0

Pins should be ____mm coronal into build up

2.0

What are complications that can occur with pins?

- fluted root shape - furcation - pulp penetration (RCT needed)

What do you do if you have a stripped pin?

move to another location at least 1.5 mm away or use a larger sized pin

_______ are used only to protect pulp in teeth that are have excavations that are deep and near the pulp

Bases

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

undercuts

Bases are not strong enough to support

grooves, boxes or other retentive features

What is a common protocol for using base?

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

What is the sequence of treatment for extensively damaged vital teeth?

-Evaluate periodontal and endodontic health (if non-vital, RCT) - Remove all caries. Often, but not always, you will remove any prior materials like old restorations or previous bases. - Re-evaluate your prep ----HOW MUCH TOOTH STRUCTURE IS REMAINING?? ----Can the defects made from caries removal beincorporated into prep for retention? ----Do you need a Build Up? or Base? or Pins? or a Post? - Proceed with Resoration