Restoration of Form and Function for Failing Disto-Occlusal Amalgam Fillings
Irfan Ahmad, BDS
A 42-year-old female patient presented for treatment of the
posterior maxilla. Clinical examination of the site revealed a failing
disto-occlusal amalgam restoration in tooth #12(24) and a temporary
mesiodistal-occlusal dressing in tooth #13(25) (Figure 1). Upon completion of
diagnostic evaluation, the clinician determined that the existing restorations
required replacement. The optimal treatment modality had to address each of
these factors while satisfying the aesthetic expectations of the patient. A
decision had to be made as to how to treat the affected dentition and restore
Due to the current controversy about fillings containing
mercury and the ever-increasing desire of patients to have more cosmetic
fillings, the use of amalgam is being questioned. In accordance with the
aesthetic requirements of the patient, it was determined to replace the amalgam
with microhybrid composite resins (ceramic optimized polymers or Ceromers) with
a high filler content (80% by weight), which would provide a suitable
alternative to more invasive or expensive procedures. The inorganic ceramic
filler would provide enhanced physical properties, while the glass particle
content would improve the aesthetics (ie, fluorescence and radiopacity) of the
restoration. Once the patient consented to the treatment, the procedure was
Occlusal contacts were obtained with articulation paper;
these marks determined the peripheral limits of the filling and ascertained the
jaw movements in various excursions. The treatment site was isolated with a
rubber dam, and the existing restorations were removed under a controlled
environment of high-speed suction to aspirate the aerosol formed during the
drilling procedure. The rubber dam ensured that the amalgam spray, created by
the bur of the turbine handpiece, did not contact the soft tissues of the oral
environment, where it could have become embedded and formed an amalgam tattoo.
Once microhybrid composite resin had been placed in the maxillary second
premolar (Figure 2), treatment was initiated at the first premolar site.
Following the removal of the amalgam restoration in tooth #12(24), a wooden
wedge was placed distally to accommodate a matrix band and establish a tight
contact point (Figure 3).
Cavity design was determined by the extent of decay and
discoloration of the tooth and completed accordingly. Once cleansing with 0.2%
chlorhexidine gluconate was completed,1 the cavity was etched with
37% phosphoric acid for 20 seconds and thoroughly rinsed. A generic bonding
agent was applied to moisten the dentin and enamel (Figure 4), and the
stainless steel matrix band was placed around the tooth.
Utilizing a flat plastic instrument, increments of hybrid
composite resin were placed in a hollow 'V' shape of 1-mm to 1.5-mm depth. Each
arm of the restoration was placed and cured separately on the buccal and
lingual axial walls. Where the cavity extended to a greater depth, an opaque
dentin shade of the composite resin was utilized to mask pulpal floor
discoloration and gain a deeper chroma in the color (Figure 5). Successive
layers were subsequently built up using translucent enamel shades. When the
penultimate layer was completed, a reamer that had been dipped into a
light-cured stain was used to shape fissure stains into the malleable composite
material (Figure 6). The final layer was then placed to complete the
stratification and to cover the stained fissure patterns, using the existing
occlusal morphology landmarks as a reference. Cuspal inclines were also
accomplished at this stage.
The rubber dam was removed to facilitate examination of
anatomy and occlusal contacts. Finishing tips and polishing pastes were
utilized to finalize cusps, inclines, and fissure patterns. The filling margins
were etched for 20 seconds (Figure 7) and rinsed until the enamel displayed a
frosted appearance. The etched enamel margins were brushed with a surface
sealing resin and cured for 20 seconds to seal any microcracks that might have
resulted from the finishing and polishing procedures (Figure 8).2
The definitive restorations exhibited correct anatomical form and aesthetics that
were indistinguishable from the natural dentition (Figure 9).
The objective for bioaesthetic, direct posterior
restorations is not merely treatment of disease to alleviate the symptoms of
the patient, but to restore form and achieve optimal function. In order to
fabricate bioaesthetic restorations, the clinician must address topography,
stratification, optical characteristics, and strength. Once the clinician has
mastered these elements and the proper clinical protocol, it is possible to provide
bioaesthetic restorations with correct form that will serve the recipient with
improved function and longevity.
* Private practice, London,
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1. Gwinnett AJ. Effect of cavity disinfection on bond strength to
dentin. J Esthet Dent 1992;4(suppl):11-13.
2. Crispin BJ. Contemporary Esthetic Dentistry: Practice Fundamentals.
Quintessence Publishing. Carol Stream,