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Inside Dentistry
August 2021
Volume 17, Issue 8
Peer-Reviewed

Conservative Amalgam Replacement and Class I Restoration

Fiber mesh and fiber-reinforced composite help manage material and tooth stresses

Jihyon Kim, DDS

For direct restorations, the use of composite resin far exceeds that of amalgam. However, retentive cavity preparations that are more ideally suited for amalgam persist. Retentive preparations may result in the excess removal of sound tooth structure, which can contribute to damaging tooth flexure. In addition, the high C-factor geometry of retentive preparations is problematic for dentin adhesion and may lead to debonding, sensitivity, and premature failure. When sound adhesive principles are understood and applied, the use of fiber mesh or a fiber reinforced composite can play a significant role in managing material and tooth stresses.

The figures present two cases featuring Class I restorations. The first case involves retreatment of a properly executed amalgam restoration with cuspal fracture—a common clinical scenario. Although conventional treatment usually entails placement of an indirect restoration, a stress-reduced direct composite restoration can be a predictable option if proper adhesive techniques are employed. A fiber mesh was used to mitigate the stresses associated with composite polymerization shrinkage and to function as a fail-safe for the compromised tooth.

In the second case, a conservative intervention is employed to restore moderate occlusal caries. Instead of utilizing strict G.V. Black preparation designs, the caries was removed in a manner in which the sound occlusal tooth structure was maximally preserved in order to mitigate potentially damaging tooth flexure under load. A fiber reinforced composite material was used in the restoration to help manage the shrinkage stresses in this conservative preparation.

About the Author

Jihyon Kim, DDS
Private Practice
Seattle and Bellevue, Washington

Pretreatment view of a molar with a failed Class I amalgam restoration and a fractured distolingual cusp. Note the isthmus width greater than 2 mm and the presence of a mesial marginal ridge (ie, peripheral rim) fracture.

Fig. 1

Removal of the amalgam revealed a fracture undermining the mesiolingual cusp that is connected to the peripheral rim fracture. Note the thin veil of occlusal enamel still present.

Fig. 2

Progressive removal of the mesiolingual cusp exposed the presence of dehydrated dentin structurally disconnected from the pulpal floor.

Fig. 3

Once the dehydrated dentin was completely removed, a stained crack could be visualized, which was a continuation of the peripheral rim fracture where microleakage had begun.

Fig. 4

Lingual view of the remaining mesiolingual cusp exhibiting intact enamel.

Fig. 5

Removal of the remaining cracks undermining the cusps.

Fig. 6

After a 35 μm saddle matrix (Contoured Matrices, TOR VM) was placed, the enamel was selectively etched, and a primer and bonding agent were applied to the preparation (CLEARFIL™ SE Protect, Kuraray Noritake). Any excess bonding agent was blotted with a dry microbrush.

Fig. 7

The dentin was coated with approximately 0.5 mm of resin (CLEARFIL MAJESTY™ Flow, Kuraray Noritake), then a peripheral composite shell was created incrementally (Filtek™ Supreme Ultra Universal Restorative [shade A2B], 3M™) (Filtek™ Supreme Ultra Flowable Restorative [shade A2B], 3M™).

Fig. 8

A 4 mm x 6 mm piece of fiber mesh bondable reinforcement ribbon (Ribbond®, Ribbond) was placed over a thin, uncured layer of composite (CLEARFIL™ AP-X, Kuraray Noritake).

Fig. 9

The bonding agent was used to wet the fiber ribbon while pushing it into the uncured composite layer below, then it was light cured.

Fig. 10

The dentin was replaced by incrementally layering composite (CLEARFIL™ AP-X, Kuraray Noritake), and then the enamel was replaced (Filtek™ Supreme Ultra Universal Restorative [shade A2B], 3M™).

Fig. 11

The final restoration was shaped and polished with carbide burs and composite polishers (H48LQ.FG.012, H379Q.FG.018, and 9525UF.RA.085; Komet USA). The primary anatomy provides function, while the smooth surfaces reduce biofilm accumulation.

Fig. 12

The final restoration was shaped and polished with carbide burs and composite polishers (H48LQ.FG.012, H379Q.FG.018, and 9525UF.RA.085; Komet USA). The primary anatomy provides function, while the smooth surfaces reduce biofilm accumulation.

Fig. 13

Pretreatment view of a molar with untreated occlusal caries.

Fig. 14

Initial access revealing decay.

Fig. 15

A caries disclosing agent (Caries Detector, Kuraray Noritake) was applied, then all caries was removed at the dentinoenamel junction. Intermittent access preserves occlusal tooth structure.

Fig. 16

The preparations were total etched and then a primer and bonding agent (OptiBond™ FL, Kerr) were applied.

Fig. 17

After a resin coat (CLEARFIL MAJESTY™ Flow, Kuraray Noritake) a fiber-reinforced composite (everX Posterior™, GC) was placed.

Fig. 18

Remaining dentin replacement (CLEARFIL™ AP-X, Kuraray Noritake) and enamel replacement (Filtek™ Supreme Ultra Universal Restorative [shade A2B], 3M™) were then performed to compete the restoration.

Fig. 19

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