Shade-taking for restorations
Shade-taking for restorations
Mimicking the positioning, contours and optical surface properties of adjacent and opposing natural teeth as realistically as possible is an important part of integrating dental prostheses inconspicuously into the mouth. The optical surface properties are summarized by the term "tooth shade" despite the fact that they include a wide range of parameters such as shade, shade gradient, brightness, shade saturation, translucency (light shimmering through light-scattering material) versus opacity (due to scattering of light), fluorescence or phosphorescence (light emission due to, e.g. UV light), glaze (due to reflection of light).
The virtually infinite spectrum comprising millions of naturally occurring tooth shades subjectively perceptible to the human eye can be reduced to a few standardised shades (clearly defined and described for objective documentation and communication) and only incur minimal aesthetic sacrifices. These are then incorporated into so-called shade guides (mostly one-dimensional/linear, rarely multi-dimensional, encompassing various parameters) such as for prefabricated denture tooth. These shade tabs are usually contoured like teeth, made of the restorative (e.g. composite or porcelain) and used for comparing with patients' teeth and/or restorations.
Shade guide
Shade guides are also available in gingival shades for imitating soft tissues such as mucosa.
As each specific surface appears differently (metamerism) when illuminated with light of differing intensities or wavelengths (sun, cloudy, dawn, artificial lighting), in order to achieve predictable results wherever possible shade-taking must be carried out under reproducible, standardised lighting conditions. To achieve these, various technical aids such as identical ring lights for dentist and technician, cameras with white balance or special electronic devices which measure spots or use standardised photos for "surveying" the various areas of the tooth (such as the incisal, dentine, cervical and proximal regions) and displaying the results to correspond with standard shade guides are employed.
Want to give it a try ...
... or need professional advice?
Get in touch with us or click Contact.
Word of the day
| English | German |
|---|---|
| apraxia |
Focus text of the month
Fixed/removable prosthetics Fixed/removable prosthetics
The patient-removable section with its retainers and connectors (e.g. clasps, precision attachments, telescopic crowns, press-stud systems, magnets etc.) is anchored on the periodontally-borne, fixed section of the restoration usually consisting of single crowns or bridge abutments supported on natural teeth, implants or implant abutments.
A removable bridge (usually "telescopic" and borne on telescopic crowns) replaces teeth with bridge units and almost never requires mucosal coverage. Other types of fixed/removable prostheses always include sections which are supported by and exert pressure on the mucosa. A coverdenture fully covers all connectors and includes teeth corresponding to those of a full denture. That section of a fixed/removable prosthesis covering the hard upper palate is referred to as the palate and sections on edentulous areas of alveolar ridge are called saddles. In fixed/removable prostheses with multiple saddles they are often connected via a metal base – in the maxilla using a major connector (transverse) and via a lingual bar in the lower. Fixed/removable prostheses may also be totally metal-free. Missing teeth are usually replaced with prefabricated acrylic denture teeth and less frequently with prefabricated porcelain teeth. When fabricating fixed/removable prostheses, special impression material and techniques are employed in an attempt to ensure that the denture base rests uniformly on the jaw. Exceeding the resilience of the mucosa or repeated "scrubbing" movements of the fixed/removable prosthesis may quickly result in pressure spots. After months or years, the bony denture base undergoes varying degrees of physiological and pressure-induced atrophy. The denture base can be relined to restore congruency. Unlike purely fixed prosthetic restorations, fixed/removable prostheses can be cleaned and repaired extraorally. In addition, examining the residual dentition and maintaining its hygiene is easier. In case of loss of load-bearing abutments, fixed/removable restorations can often be extended without needing remaking. Placing implants to increase the number of abutments supporting fixed/removable prostheses results in firmer, more stable retention and relieves the loading on the residual natural dentition. Fixed/removable prostheses replacing not only missing teeth, but also other anatomical structures are referred to as maxillofacial appliances. Tooth/implant-borne bridges are normally not considered to be fixed/removable restorations but rather purely fixed prostheses (possibly operator-removable) supported on natural teeth and implants. |
Fixed/removable denture including CoCr, clasps, precision attachment and double crowns (demo model)
Fixed telescopic crowns (primary)
Removable partial denture (secondary section)
Removable lower partial denture