COMPLEX PREPS, PINS, RESTORATIONS

A core or foundation implies that the amalgam restoration is not what

Definitive - a full coverage restoration will be placed over it

A large, complex restoration that MAY serve as a definitive restoration itself OR as a temp until long term prognosis of tooth/final tx plan is determined

Amalgam buildup

Complex amalgam build ups are used for what tooth

Best restored by a ______ restoration

Compromised

Indirect (onlays, crowns etc)

Indirect restorations help prevent tooth _____ caused by _________

Fracture

Mastication

Inadequate conventional restorations can be enhanced retentively by what

Pins, slots, grooves

Indications for complex amalgams (3)

Large carious excavations

One or more cusps require capping

Control restorations

Complex amalgams are used as control restorations in teeth with what (3)

Questionable perio and pulpal prognosis and severe caries

Complex Amalgams can serve as control restorations to...

Isolate _____ from ______

Provide anatomic _______ to improve ____ health

Facilitate control of ______ and _____

Provide resistance to (2)

Pulp from oral fluids

contour - gingival health

caries and plaque

Tooth fracture and propogation of fracture

Alternative to amalgam for control restorations at musod

Equia forte

Contraindications for complex amalgams (3)

Occlusal problems (bruxers)

Direct cannot be placed properly

Esthetics

Advantages of complex amalgams

conservation of _______

_____ time

_________ and _______ forms

________

Tooth structure

Appt (less)

Resistance and retention

Economics

Complex Amalgams preserve more ________ tooth structure than indirect

Unaffected

How do complex amalgams increase restistance form?

Retention?

Prep features (pins, slots, coves)

Cuspal coverage increases fracture resistance

Disadvantages of complex amalgams (4)

Tooth ______

_____ form

Amalgam is more _______

________

Anatomy - hard to re-establish

Resistance - doesnt protect from fracture as much as indirect

Aggressive to remove affected structures

Pins

Although a useful restorative adjunt, they present their own problems

Pins

Retention groove in dentin whose length is in a horizontal plane

Slots

Slots are used in conjunction or alternative to ____

Pins

Slots are placed with which bur(s)

Small round - 1/2, 1 or 330

Slot dimensions

Atleast .5mm deep and 1 mm length

Slots may be _______ or ________

Continuous or interrupted

Retention groove in _____ plane

Vertical

Coves are usually ____ than slots

Dimensions?

Smaller

Same as slots (atleast .5mm deep and 1 mm length)

Proximal locks are typically placed with what bur

Where?

Small round* or 169L

.5mm inside DEJ

Indications for pulp chamber retention (3)

Endo tx teeth only

Dimension of pulp chamber is adequate to retain amalgam core

Adequate dentinal thickness

Considerations for Pulp Chamber retention:

If chamber is <2mm - extend how far in to the RCS (root canal space)

>4mm

2-4mm

No extension (no benefits)

Three types of pins

Cemented, friction locked, self threading

What type of pin is most common

What else is good about it

Self threading - most retentive

What materials are used for pins (3)

Titanium

Gold plated

Stainless steel

Threads of pin engage _____ and retain ______

dentin

Amalgam

What size (diameter) pins should you use for :

Molars

Bicuspids

Anterior (2)

.78mm

.61 mm

.48, .38 mm

Advantage of pins

Increased retention

Disadvantages of pins:

Dentinal _______

______ amalgam strength

______ of tooth structure

_______ or ______ pins

Microfracture

Decreased

Perforation

Broken or loose

How do pins decrease amalgam strength

Voids in and around pins

Tensile and horizontal strengths are decreased

An excessive # of pins can do what to the tooth

Fracture tooth and weaken amalgam

What should you do when determining # of pins

Weigh risk vs benefits

What 4 things should you evaluate when considering pins (4)

Missing tooth structure

Amount of dentin remaining

Amount of retention required

Size of pins

When only 2-3 mm of occlusal gingival height has been lost - do you need a pin?

Why?

NO - Enough tooth structure remains for retention

Where to place pins

Near line angles of teeth

Pin Placement Principles:

One pin per (3)

Use ______ number possible to achieve retention

Requires ______ of dentin around entire pin

Pin should be placed no closer than ______ from DEJ or _____ from external tooth surface

Line angle, cusp or axial wall

Fewest

.5mm

.5 - 1mm

Pins must be placed on a ____ surface - why?

_____ lengths (______) into dentin and amalgam

Flat - if not, wont reach adequate depth

equal - 2mm -

Pins should not be _______

Bent

Minimum inter-pin distance:

Minikin

Minum

Regular

3mm

5mm

7mm

To determine pin placement you must understand and consider:

_____ anatomy (_____ and _____)

Tooth _______

Patient ______ - why?

________

Avoid ____ areas due to possible _______ - use ______

Pulpal - horns and chamber

Contours

Age - younger = larger pulp

Occlusion

Furcation - perforation - perio probe

Pin placement:

Ensure ____ surfaces

Use ______ bur pilot hole (size)

Consider _____ and ____ anatomy

Generally parallel to _______

Flat

1/4-1/2

internal and external

long axis

Pin Placement:

Determine ______ and place ____ divot

Drill pin channel - no more than ___ passes to avoid ______

What handpience?

Place using ____ speed or ______

Place _______

Positioning - pilot

2 - oversizing

Latch type

Slow - universal hand driver

Restoration

Depth of pulpal Floor

Depth of box/gingival seat

Height of axial wall

Width of gingival seat

1.5+

Dictated by caries

Dictated by caries and other prep designs

1-1.5

What type of amalgam do we use?

why?

Spherical

Adaptation into pin should be easier, minimizes voids/weakening

Optimal placement/setting properties for larger restorations