ch 12 porcelain esthetics

when matching the vital tooth, exact reproduction is impossible due to

• light reflection and refraction duplication

• enamel translucency

• dentin opacity

• subtle hue, chroma, and value changes

(luckily the eye is not as sensitive to color as it is to outline and surface form)

visual perception consists of

• light

• movement (does not apply to this topic)

• outline form

• surface form

• color

how to compensate for higher light reflection of porcelain (4)

• higher chroma (unattractive result)

• lower value (better choice)

• slight lingual tooth position

• inc incisal curvature

we have a high sensitivity to outline form bc…

tooth is surrounded by a dark background

outline form

• should be in harmony w: Facial structures, sex, and temperament

• strength vs softness → incisal edge contour (square vs ovoid)

• tooth size to be determined visually or perception by width of face

surface formed is determined by

pt facial features

• gingival-incisal profile

• mesial-distal profile

surface texture in light reflection

• LR should be irregular and diffused

• ST more emphasized than natural teeth

• horizontal lines accent width

• vertical lines accent length

you can use color for contour enhancements likes:

• lines: Accent width and height

• shadows: Add depth

• angles: add highlights and boldness

• curved surfaces: Add softness and less definition

how to alter visual perception to make a tooth look shorter

• define the CEJ well

• staining the root portion darker

• addition of gingival colored porcelain to root portion

• use a gingival color stain

• surface texture: horizontal lines

how to alter visual perception to make a tooth look longer

• strong color contrast w gingiva

• surface texture: vertical lines

• surface form: vertical concavities

how to alter visual perception to make an arch look narrower

• diastema closure

• dominant display of mesial angles of incisal and canines

• lateral overlapping centrals

• darking canines and premolars

how to alter visual perception to make an arch look expanded

• proximal contacts labially

• flat surface form w horizontal lines

• distal surfaces of laterals and canines labially

• canines and premoalrs same shade, as light as incisors

What illusion is commonly used for anterior pontics in small edentulous spaces

crowding illusion

for replacement of ONE premolar, what should the MB and DB surface look like

• MB: normal size and shape

• DB: surface/slope shorter or absent

for replacement of TWO premolars w one molar pontic, what should the MB and DB surface look like

• one molar: MB cusp size and shape with stained deep buccal groove

• premolars: normal MB and shorter DB

types of characterization

• surface form/contour

• surface texture/detail

• surface staining

staining that can be done

Shade Modifications

• Hypocalcification

• Proximal Staining

• Enamel Cracks

• Stained Craze Lines

• Exposed Dentin

• Incisal Halo

• Translucency

types of glazing techniques

• autoglazing

• overglazing

post ceramic soldering techniques

• torch

• oven

post-ceramic soldering indications

• combined gold and PFM FPD

• ideal contouring of individual units

• long span FPD

• multiple unit splint

• poor fit during delivery apt

post-ceramic soldering steps

1. verify fit

2. porcelain stained and glazed

3. prepare connector area: clean and rough surface, flux (semi and non-precious alloys)

4. resin index, plaster index or both

5. soldering investment assembly

soldering problems

• incomplete connector

• failure to fit

• damaged porcelain

• melted casting