Class IV Dentistry Techniques and Shade Guide Overview

class 4 is used for

- caries or defects

- proximal surfaces

- anterior teeth

- with incisal edge involvement

indications for class 4

- fracture

- caries

- congenital defects

- replacement of an existing restoration

class 1 dental fracture

only enamel is fractured

class 2 dental fracture

enamel and dentin fractured (pulp = ok)

enamel fracture (uncomplicated crown fracture)

fracture of only enamel w/ substance loss

enamel-dentin fracture (uncomplicated crown fracture)

fracture of enamel + dentin (pulp = ok)

enamel and dentin fractures are typically treated with class ___ restoration

4

caries and class 4

helpful with chronic caries

congenital defects that class 4 is used to treat

peg-shaped lateral incisors

class 4 can be used to replace an

existing, discolored restoration

dimensions of color

hue, chroma, value

hue

color

chroma

saturation

value

lightness or darkness

additional appearance attributes

- opacity

- translucence

- gloss

- opalescence

- florescence

opacity

ability of a material to block the passage of light through the material

translucency

ability of a material to allow light to pass through

gloss

shine or luster on a smooth surface

opalescence

reflected light = blue

transmitted light = orange/ brown

fluorescence

absorption of light by a material + spontaneous emission of light in a longer wavelength

fluorescence is normally seen under ___ lighting

UV

what is important to give the restoration a lifelike appearance?

fluorescence

what can be used to aid is removing an old restoration?

black light

CIE LAB components

L* = lightness (value)

a = -a green : +a* red

b = -b blue : +b* yellow

which axis is each CIE LAB component on?

L (value) = vertical axis

C*a,b (chroma) = distance from vertical axis

h*a,b (hue) = angle on horizontal plane

CIE lab color difference equation

color difference = ΔE*ab

3 dental shade guides

1. VITA Classical and Classical-keyed products (empirical conception)

2. VITA 3D-Master shade guides (scientifically grounded)

3. Other (proprietary conceptions)

vita classical shade guide range

A1-D4

vita classical shade guide letters

A-D represent hue

A = red

B = yellow

C = grey

D = red-grey

vita classical shade guide numbers

1-4 represent CHROMA

1 = least saturated

4 = most saturated

vita classical value arrangement

B1-C4

shade selection should occur before ___ because it only takes ___ of dehydration for shades to look different

isolation

1 minute

how long after isolation does it take teeth to become their original shade again?

24 hours

teeth are ___ and the same tooth may even have ___ shades

multichromatic

multiple different

mock-shade selection technique

1. apply small amount of composite to tooth w/out etch/bond and cure it

2. do this w/ multiple shades

3. remove non bonded composite w/ hand instrument

is shape or shade more noticeable?

shape

order of prep

1. remove caries if present

2. remove unsupported enamel

3. bevel 0.5-2mm

size of bevel depends on

- size

- location of defect

- retention

- esthetics

same restoration steps and rules apply to ___ but there are many additional techniques/ tools that can be used to ___

all resin composite restorations

restore a class 4

advantages of lingual matrix technique

- predictable outcomes

- pt is involved in plan before fabrication of restoration

- decreases amount of finishing/ polishing

- saves time

disadvantages of lingual matrix technique

- more lab time

- two appt

- more expensive

most common reason for class 4 restoration

fracture

what 4 classifications are most relevant for class 4?

1. class I = enamel fracture only

2. class 2 = enamel + dentin fracture (pulp=ok)

3. enamel fracture = loss of tooth substance in enamel only

4. enamel-dentin fracture = enamel + dentin fracture (pulp=ok)

another name for enamel fracture according to WHO classification is

uncomplicated crown fracture

another name for enamel-dentin fracture according to WHO classification is

uncomplicated crown fracture

class four is indicated when ___ and ___ are fractured, but ___ is not involved

enamel

dentin

pulp

another name for CIE lab is

color sphere

what colors are included in the color sphere?

all colors in the entire world

purpose of color sphere

gives every color a number

vertical axis of color sphere is

value

distance away from vertical axis on color sphere is

chroma

angle on horizontal place on color sphere is

hue