Laminate Resin Composite Techniques
The aim of this chapter is to consider how laminate resin composite techniques can be used to provide aesthetic restorations for anterior teeth.
On reading this chapter practitioners will become familiar with the materials and techniques best suited to improve the appearance of anterior teeth with laminate resin composite restorations.
Resin composites have developed in tandem with dentine adhesive systems to the extent that resin composite adhesive systems can be used effectively to restore extensive defects in anterior teeth. Linking dentine-bonding agents and resin composites to enamel and dentine frequently removes the need for mechanical preparation. Caries removal and ensuring that the surface is clean and dry to maximise bond strength is all that is required for the restoration of many anterior teeth. This has considerable advantages for patients in that already damaged anterior teeth can be restored without further tooth preparation or the use of a laboratory to produce indirect restorations.
Current resin composites contain translucent enamel and dentine shades. Some manufacturers also provide opaquing or bleaching tooth shades, which are rarely needed. The resin composites are built up in a similar manner to making a porcelain crown in the laboratory (using core, dentine and enamel shades). The technique for these materials is not dissimilar to other direct build-up techniques, except that the majority of the build-up is done with dentine shades, with very little enamel shade used. A common mistake is to use too much of the enamel shades or the translucent shades, which can give a restoration that is very grey or blue.
The advantage of most porcelain laminate veneer techniques is minimal tooth preparation. The one limitation of this concept (especially on canines) is the potential to produce undercuts during tooth preparation relative to the path of insertion. Very bulbous canines, if minimally prepared, will have an undercut between the mesial and the distal surfaces. Alternatively, some clinicians advocate removing more tooth tissue to create space for porcelain and to remove the undercut, but that reduces the advantage of the technique being minimally invasive. Resin composite can be placed where it is needed and generally without tooth preparation (Fig 4-1).
Another advantage of direct resin composite veneers is the capacity to repair and refurbish the restoration over time. Minor fractures or localised staining or caries can be either removed or repaired with a resin composite used in conjunction with a dentine-bonding agent. It is useful when bonding old to new resin composite to use a silane-bonding agent to improve the bond between the two increments of material. Porcelain fractures can be repaired with resin composite but never look quite the same and, unless hydrofluoric acid is used, it is unlikely that a bond between the porcelain and the tooth or resin composite luting cement will be achieved.
Directly placed resin composite laminate restorations have another significant advantage in that the technique is very good for young (adolescent) patients not of an age to justify porcelain laminate veneers. Equally, directly placed resin composite laminate restorations are to be preferred when gingival maturation is not complete.
Probably the most significant disadvantage with directly placed resin composites is the clinical time needed to produce an aesthetic result. Even though porcelain veneers involve a laboratory phase and consequently additional cost, it is the technician who spends the time shaping, contouring and colouring the restoration. The clinician need only lute the restoration into place. For some clinici/>