Failed plastic restoration in LL6

LL6 has ditched amalgam. There are cracks in the enamel overlying the mesiobuccal cusp. This has resulted in secondary caries. LL5 has been provisionally restored following the repair of a root perforation

[The original motive for the referral.]

Gross Caries in LL6

Removal of the amalgam from LL6 shows the true extent of the caries.

Note how the floss ligature pulls the rubber dam subgingivally in the interproximal regions maintaining good isolation.

Cavity extent

Caries is removed using hand and rotary instruments. The colour of the dentine does not reflect the degree of demineralisation or infectivity of the remaining dentine.

The dentine is disinfected with 5% NaOCl prior to preparation for bonding.

Sectional Matrix is the first choice when placing Class II resin restorations

Sectional matrix applied and adapted with wedges.

The contact areas are burnished with a belvedere style instrument. Rings are used to separate the contact areas.

Etching of Enamel Only

Precise etching of the enamel alone is possible with the operating field magnified. [In this instance X 6.7].

The enamel is etched for 15 seconds prior to etching the dentine.

Etching of Entire Cavity

The entire cavity, both enamel and dentine are etched for a further 15 seconds.

This ensures that the dentine is not over etched -a common cause of post operative sensitivity.

Washing of etchant

The cavity is washed copiously with an air/water mixture. To avoid over-drying of the dentine air is not used dry the cavity.

Gross pools of water are aspirated using a micro aspirator. [Luer Vacuum Adapter and EndoEze - Ultradent]

Drying of dentine

In order to ensure that the dentine is not overly dry, air from a standard 3-in-1 syringe is avoided.

Instead, microsponges are used to gently soak up any excess moisture. These can be held in fine tweezers.

Dentine prepared for bonding

Under magnification it can be seen that no pools of excess moisture remain within the cavity.

A common complication of air drying dentine is volumetric shrinkage by its desiccation.

Interproximal and "dentine" build up

Interproximal "enamel" contacts are developed first. Once the conversion to a Class I cavity has been completed the dentine element is built up incrementally.

By using smaller composite increments the effects of the C-factor are minimised.

Enamel build up and characterisation

The enamel layer is completed again incrementally. The rubber dam is removed and occlusal refinement made.

The tooth can then be characterised and polished.

2 years post operatively

Notice the lack of ditching or crazing in the enamel or of the resin restoration. This is achieved by the accurate placement of the composite increments. This maintains stresses at placement to a minimum.

This degree of precision is only possible with the higher levels of magnification.

2 years post operatively

Notice the occlusal morphology of the resin restoration in the LL6. Correct occlusal anatomical form distributes stresses evenly and thus minimises those within the restoration.

LL5 has been restored to function with a porcelain-fused to metal crown. [Technician: Ian Stapleton]

2 years post operative radiograph

Radiograph showing interproximal contacts and size of the resin restoration in LL6. LL5 has had the mesila perforation repaired with MTA.

The tooth has been restored with a non-metalic post, a resin core and porcelain fused to metal crown.