Aesthetic Principles in Dentistry and the Incisal Corner Restoration Flashcards
Factors contributing to appearance of teeth
- outline form
- contour
- symmetry
- proportion
- colour
Secondary anatomy
Vertical macro texture
Developmental grooves
Line angles
Surface regularities
Consider a light beam striking an opaque block, if the surface is smooth it is..
Specular - mirror like reflection
Natural teeth exhibit high specular reflection (especially when wet)
If the surface has roughness…
Diffuse reflected light is scattered from the surface
Natural teeth exhibit diffuse reflection
Natural teeth are
Translucent
Consider a light beam striking a translucent block, how will this act and affect the tooth?
Some of the light that is not reflected may be transmitted
Some of the transmitted light may be absorbed, diffracted or re-emitted
Specular reflection but also transmittance of light through the object which will be detracted or re-emitted - this changes the characteristics of the tooth and therefore the materials used need to manage this
When white light strikes an object, 3 things can happen…
Reflected
Absorbed
Re transmitted
Tooth anatomy
Primary
Secondary
Tertiary
Primary anatomy
Tooth shape form
- Composite placement
- Sof-lex disc
- Coarse diamond bur
Secondary anatomy
Mamelons
Line angles
- So flex discs
- Enhance point
- Reduced speed red grit diamond bur
Tertiary anatomy
Perikymata
Coarse grit diamond bur reduced speed
Bonding protocol
Appropriate moisture control
Following manufacturers instructions based on system used
Optimising bond where possible
Isolation
Optragate
- regular
-small
- junior
Spit dam
Individual tooth isolation
Optragate isolation
- patient comfort
- ease of placement
- pooling of saliva
- ability to lose compliance
- moisture when breathing
Individual tooth isolation
Application
- fiddly
- multiple steps
- risk of poorly adapted emergence
- excessive for veneer type work
- ideally requires floss ties for optimum isolation
Absolute isolation with rubber dam increases bond strength to enamel, independent of the adhesive system
Not using rubber dam reduces sheer bond strength by 50%
