COMPOSITE TECHNIQUE    SMILE DESIGN     COMPANIES/MATERIALS    MATERIAL SCIENCE

                            CLASS 3 TECHNIQUE

Maxillary incisors have multiple defective class 3 composite restorations.  Various size defects require different numbers and positioning of composite layers to minimize negative affects or shrinkage.  A large defect that comes within 1 millimeter of the incisal edge requires removal of the unsupported incisal enamel becoming a class 4 restoration.  Thin enamel areas that receive direct force will fracture and are removed.

Large defects that extend into the gingiva and below enamel will have microleakage from the combination of reduced bond strength of dentin or cementum bonding, stress from curing shrinkage and the stresses of thermocycling.  Layering techniques creating a gingival floor with the first layer, multiple layer placement, proper enamel/dentin bonding minimizes problems.  Flowable composite lining walls can also improve internal stresses.

Extension of class 3 restorations to the facial compromises esthetics, however, beveling enamel on facial areas helps color blending and produces cross section of enamel for improved bond strength.  Enamel is beveled only if there is enough thickness.  Thin enamel requires too much exposure to the facial and esthetic concerns when removed.

Large defects show through darkness in the back of the mouth. Use of a lingual opaque or dentin layer minimizes show through from darkness.  In addition, composite is exposed to occlusial forces causing wear.  Selection of lingual composite must resist wear.