Case by Dr. Max Andrup

This patient presented with a fractured amalgam restoration in the occlusal aspect of the mandibular right first molar. The cavity was shallow resulting in a very favourable C-factor. The C-factor describes the relationship between bonded and unbonded restorative material surfaces and is used as an indicator for polymerization shrinkage stress development in a cavity. Hence, it is essential to manage this factor when working with resin composites.

Fig. 1. Initial situation with the fractured amalgam restoration. In the distal aspect of the restoration, some recurrent decay is also visible.

Fig. 2. First molar ready for a new restoration after removal of the amalgam and bevelling of the enamel.

Fig. 3. Selective etching of the enamel prior to the application of CLEARFIL™ SE Protect into the cavity. Selective etching is performed in order to maximize the bond strength to enamel (by etching) and to dentin (without etching).

FINAL SITUATION

Fig. 4. Final situation after restoration of the cavity with CLEARFIL MAJESTY™ ES-2 Universal in the shade U developed for posterior restorations. The favourable C-factor and the fact that the polymerization shrinkage stress produced by the selected material is very low provide the conditions for a good long-term behaviour of the new restoration.

Dentist:

Dr. Max Andrup graduated from the University of Umeå in 2010 and today runs his private practice in the city of Hudiksvall, Sweden. He has a passion for restorative dentistry with a biomimetic approach.

Case by Max Andrup

The maxillary right first premolar of this patient had a huge defect on the lingual aspect extending subgingivally. In order to facilitate proper working field isolation for the placement of an onlay, it was decided to elevate the margin using the deep margin elevation (DME) technique. Moisture control is more easily handled with a matrix and composite compared to trying to keep a deep box dry at the placement of an indirect restoration. The preferred method used to maximize the bond strength to dentin was immediate dentin sealing combined with resin coating, while the luting material of choice was warmed light-curing resin composite (CLEARFIL™ AP-X). It shows a superior performance compared to dual-cure luting materials e.g. in terms of conversion of monomers to polymers, time available for excess removal, bio-mechanical properties and polymerization shrinkage stress.

Fig. 1. Pre-operative situaton with clearly visible deep distal margin. In reality, it was even deeper than the picture reveals. The Brinker Rubber Dam Clamp B4 placed here is a life saver in cases with subgingival margins. The buccal wall was still intact. We planned to reduce it to allow the onlay to cover it completely, allowing it to work under compression and thus increasing the fracture resistance.

Fig. 2. Situation after placement of a sectional matrix on thedistal aspect of the tooth. In order to retract the rubber dam mesially, PTFE tape was placed in this area. This allowed me to seal the dentin in a perfectly dry environment. For immediate dentin sealing, the smear layer developed on the dentin immediately after tooth preparation was compacted with the aid of air abrasion (50 μm alumina particles) to provide for the best possible bonding conditions, followed by the application of the bonding agent (CLEARFIL™ SE Protect). Afterwards, the bonded dentin was covered with a thin layer of flowable resin composite (CLEARFIL MAJESTY™ ES Flow). This resin coating ensures that the hybrid layer is thick enough and that the dentin is perfectly sealed.

Fig. 3. After immediate dentin sealing and resin coating. The hybrid layer was left to mature for approximately five minutes. This measure leads to an increased bond strength to dentin, which prevents issues that might occur due to the polymerization shrinkage stress occurring after composite placement. Subsequently, CLEARFIL™ AP-X was applied in small increments, starting in the distal box. In this way, the biobase was built up to the desired height. The main arguments for using CLEARFIL™ AP-X as a replacement for deep dentin are that the modulus of elasticity is within the same range as that of dentin and it exhibits an extraordinarily low polymerization shrinkage.

Fig. 4. Lateral view of the tooth at the day of delivery. View of the tooth at the day of delivery after rubber dam placement and prior to air-abrasion treatment of the biobase, which was performed to remove any remaining temporary cement. Following try-in, the lithium disilicate onlay was cleaned with KATANA™ Cleaner and pretreated with CLEARFIL™ Ceramic Primer. The biobase was sandblasted again for cleaning.

Fig. 5. Onlay in place after selective etching of the enamel with 35 % phosphoric acid etchant, and application of CLEARFIL™ SE Bond to the biobase and the intaglio of the onlay as well as luting with heated CLEARFIL™ AP-X. Excess composite was removed and the composite light cured.

FINAL SITUATION

Fig. 6. Occlusial view of the luted restoration.

Case by Max Andrup

This is the story of cusp fracture due to cuspal tension. This is a common weakness of amalgam-restored teeth associated with expansion of the restorative material. The affected maxillary right first premolar was restored with a crownlay.

For seating of the crownlay, the use of warmed light-curing resin composite (CLEARFIL™ AP-X) has proven its worth. Compared to a dual-cure luting resin, the selected material offers many benefits including the fact that the heat assists in the conversion of monomers to polymers, the time available to remove excess is almost unlimited, and the composite offers better bio-mechanical properties as well as a lower polymerization shrinkage stress.

Fig. 1. Pre-operative situation. The patient requested for an emergency appointment, where we temporarily fixed the lost buccal cusp and made a new appointment for a crownlay preparation. After removing the amalgam and temporary filling, the remaining amount of tooth structure was quite beneficial with a large lingual cusp and a ring of enamel around the whole tooth.

Fig. 2. The decision was made to reduce the lingual cusp and to place a crownlay working in compression. As the thickness of the cusp was adequate for an onlay, this treatment option would have been equally suitable. After tooth preparation, immediate dentin sealing was performed: For this purpose, I air-abraded the dentin to remove the smear layer and give the adhesive the best condition for a strong bond to dentin. Then, CLEARFIL™ SE Protect was applied to the tooth surface and covered with a thin layer of flowable resin composite (CLEARFIL MAJESTY™ Flow) to ensure a total seal.

Fig. 3. The resin composite surface was air-abraded with 50 μm zirconia particles, followed by selective etching of the enamel with a 35-percent phosphoric acid etchant. After try-in of the crownlay made of lithium disilicate, the tooth surface and the restoration were cleaned with KATANA™ Cleaner.

FINAL SITUATION

Fig. 4. The cleaned crownlay was pre-treated with CLEARFIL™ Ceramic Primer, before warmed CLEARFIL™ AP-X was applied to both tooth structure and restoration for luting. The colour of the crownlay matched the colour of the adjacent premolar, while the visible part of the restored tooth’s remaining structure was stained from amalgam corrosion.

Case by Max Andrup

This patient had requested for an emergency appointment and presented with severe erosive tooth wear in several teeth, a crack in the mesial wall of the maxillary first molar and a failing direct restoration with recurrent decay on the adjacent second premolar. I decided to replace the direct resin composite restoration immediately as this was the main cause of discomfort. It was decided to restore the other defects during the next appointment.

The resin composite of choice was CLEARFIL MAJESTY™ ES-2 (Universal shade concept), an innovative material with a single universal shade designed for posterior restorations. The manufacturer claims that, due to the integration of Kuraray Noritake Dental Inc.’s light diffusion technology, this universal shade nicely blends in with the surrounding tooth structure virtually independent of its colour. Curious about the real potential of this concept, I wanted to put the material to a test.

Fig. 1. Pre-operative situation revealing signs of severe erosive tooth wear, a cracked mesial wall of the first molar and a failed filling on the second premolar with recurrent decay.

Fig. 2. Appearance of the tooth after removal of the direct composite restoration. The recurrent caries is obvious.

Fig. 3. Caries Detector applied to the decayed tooth structure.

Fig. 4. Establishing of a peripheral zone totally free of caries with the aid of Caries Detector. It may be useful to apply the dye several times.

Fig. 5. The final situation after several applications of Caries Detector. The peripheral zone is completely free of caries, which is a strict requirement for the establishment of a perfect seal during bonding. Affected caries stained light pink is not removed not to risk going near the pulp.

Fig. 6. Build-up of the proximal wall with CLEARFIL MAJESTY™ ES-2 (U shade) after the application of CLEARFIL™ SE Protect and a small layer of CLEARFIL MAJESTY™ ES Flow in a thickness of about 0,5 mm. By focusing on the proximal wall connecting to enamel first, the hybrid layer is given the time needed to mature. Not putting a new increment on top of the hybrid layer for the first five minutes will lead to an increased bond strength to dentin.

FINAL SITUATION

Fig. 7. Appearance of the tooth immediately after finishing and polishing. Although the rubber dam is still in place and the tooth structure is not yet rehydrated, it is evident that the composite blends in very well with the remaining tooth structure to form a seamless margin.