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References

Mackenzie L, Parmar D, Burke FJT, Shortall AC. Direct anterior composites: a practical guide. Dent Update. 2013; 40:297-317
Manauat J, Salat A. Layers: An Atlas of Composite Resin Stratification.: Quintessence Publishing; 2013

Technique Tips: How to Make a Customized Shade Guide

From Volume 46, Issue 4, April 2019 | Pages 396-397

Authors

Louis Mackenzie

BDS, FDS RCPS FCGDent, Head Dental Officer, Denplan UK, Andover

General Dental Practitioner, Birmingham; Clinical Lecturer, University of Birmingham School of Dentistry, Birmingham, UK.

Articles by Louis Mackenzie

Article

Contemporary composite materials must have advanced colour matching properties to satisfy patient and professional demand for high-quality aesthetic restorations.

Precise colour matching remains one of the most challenging tasks in clinical dentistry, due partly to the widely acknowledged limitations of proprietary shade guides:1,2

  • Colour ranges and distributions of shade guides are different from those of natural teeth;
  • The colour of marketed restorative materials is often significantly different from corresponding shade tabs;
  • The arrangement of shade tabs is not always logical and user-friendly;
  • Conventional shade guides are not often fabricated from the same restorative material that will be used clinically;
  • Simultaneous interpretation of single shade tabs next to adjacent teeth exhibiting complex colorations and optical properties is challenging;
  • Translucency and opacity are not readily apparent with most shade guides;
  • The colours of teeth, restorative materials and shade tabs may differ when viewed under different light conditions (metamerism);
  • There is no colour compatibility between commercially available restorative materials.

    • While colour matching for direct composite restorations may be optimized by studying light cured material samples placed on teeth, this is of limited benefit when using polychromatic layering techniques. Here the final colour of a restoration is derived from a combination of opaque ‘dentine’ and overlying translucent ‘enamel’ shades.

    To overcome this problem an innovative silicone template and associated components (My Shade Guide, Smileline™, Switzerland) has been developed (Figure 1) and may be used according to published guidelines2 to create personalized shade tabs with standardized dimensions of the ‘enamel’ and ‘dentine’ layers. Step-by-step practical tips for the construction of a customized shade guide follow (Figure 2 to Figure 18):

  • An initial increment of a translucent ‘enamel’ shade composite is placed into the base of the silicone template (Figure 2).
  • The transparent silicone top of the template is then firmly located on the base (Figure 3).
  • The ‘enamel’ layer is then light cured through the silicone template for 20 seconds (Figure 4).
  • The template top is removed to reveal the ‘enamel’ increment. Lateral relief channels allow excess material to be extruded, but with experience the amount of excess can be minimized (Figure 5).
  • The ‘enamel’ layer is then light cured again for a further 60 seconds (Figure 6).
  • To refine the technique, the ‘enamel’ sample may be removed and measured with a thickness gauge to ensure that it conforms to the standardized, clinically relevant, thicknesses (0.2 mm cervically, 0.5 mm midpoint and 0.7 mm incisally) (Figure 7).
  • The ‘enamel’ shell is then filled with a ‘dentine’ shade to create a layered shade tab of known thickness. The rotating cylindrical silicone tip of a specialized instrument (CompoRoller™, KaVo Kerr, Bioggio, Switzerland) simplifies this stage (Figure 8).
  • Clear matrix strip may be applied to the palatal surface of the sample to eliminate the oxygen inhibition layer on polymerization (Figure 9).
  • The ‘dentine’ layer is then light cured through the matrix strip for 60 seconds (Figure 10).
  • The standardized, layered sample is then removed from the template in readiness for finishing and polishing (Figure 11).
  • Coarse finishing discs may be used to remove gross marginal excess and finer discs to refine the outline form (Figure 12).
  • Buffing discs, used with light pressure, are all that is required to create a high polish on the labial surface of the shade tab sample (Figure 13).
  • Superglue is then applied to the palatal surface of the shade tab in readiness for placement of a snap-on clip. Use of a brush simplifies this process (Figure 14).
  • The snap-on clip is located on the palatal surface of the shade tab and is left for 10 minutes (Figure 15).
  • The shade tab may then be clipped onto the specialized handle which is marked using an indelible felt pen with the prescribed shade combination for future reference (Figure 16).
  • Single colour shade tabs may also be constructed and compared to proprietary shade guides, eg Vita Classical™ (Vita Zahnfabrik, Germany) (Figure 17).
  • Shade tabs should ideally be displayed and organized in a specialized stand (Figure 18).
    • Figure 1. My Shade Guide silicone template.
    Figure 2. Translucent ‘enamel’ layer.
    Figure 3. Template top located.
    Figure 4. 20 second light cure.
    Figure 5. ‘Enamel’ layer.
    Figure 6. 60 seconds light cure.
    Figure 7. Measurements to confirm prescribed thicknesses.
    Figure 8. Application of ‘dentine’ layer.
    Figure 9. Clear matrix strip.
    Figure 10. Light cure the ‘dentine’ layer.
    Figure 11. Shade tab removed from template.
    Figure 12. Excess removal.
    Figure 13. Buffing.
    Figure 14. Superglue.
    Figure 15. Snap-on clip.
    Figure 16. Layered shade tabs.
    Figure 17. A2, A3, A3.5 and A4 composite shade tabs above corresponding Vita Classical™ shade tabs.
    Figure 18. My Shade Guide stand.

    An unlimited range of shades may be created using this technique to enable fast, efficient, precise colour matching during direct restorative procedures.