A successful restoration requires not only a conservative approach to preparation but also a well-designed and sustainable filling technique.
In spite of the advances in esthetic dentistry, composite shrinkage remains
problematic and may be a possible reason for the failure of a restoration.
Composites shrink between 1.5 and 5 per cent by volume when they
polymerise. Sophisticated and at times complex filling techniques based on
the C-factor (configuration factor) are deployed to offset the effects of polymerisation shrinkage: These techniques require the composite to be placed in small individual increments (less than two millimetres) and each increment to be polymerised separately.
With the introduction of the bulk
fill technique (Tetric EvoCeram Bulk Fill); this procedure has now been made considerably easier. Tetric EvoCeram Bulk Fill can be placed in single increments of up to four millimetres, allowing a “singlelayer technique”. The light-curing, radiopaque nano-hybrid composite combines all the beneficial properties of Tetric EvoCeram in one product. Two different indications and the route to treat them are shown on the basis of the two patient cases described below.
First patient case
Caries lesions were detected in teeth 46 and 47 of a 25-year-old female patient. She had a good general health status. After an analgesic had been administered, the carious lesions were removed and the cavities were rinsed with 2 per cent chlorhexidine digluconate solution. Etching gel (Total Etch) was first applied to the enamel margins and, following a waiting time of 15 seconds, to the dentin. The overall etch time was 30 seconds. Subsequently,
the etchant was rinsed off with water and the cavity was dried to medium
dryness. Application of ExciTE F single-component adhesive is recommended to condition the cavity for the adhesive restoration technique.
This material contains primer, adhesive and several solvents all in one. For
the adhesive to unfold its full effect, it should be applied on the dentin while it is slightly moist. The difficult part for the dentist is to determine the dentin moisture level that favours the optimum penetration of the adhesive. In effect, this is a balancing act: if the dentin is too moist, the formation of a homogeneous adhesive bond is impeded, resulting in what is known as the overwet phenomenon (enclosure of water bubbles at the interface). If,
on the other side, the dentin moisture level is too low, the collagen matrix may collapse.
This may lead to postoperative sensitivity, marginal discoloration and, sooner or later, to secondary caries. It is therefore important to follow the manufacturer’s instructions for use.
The adhesive (ExciTE F) was applied to the etched tooth structure and the
solvent contained in the adhesive was dispersed to a thin layer with a weak
stream of air. Next, the adhesive was light-cured for about ten seconds using the Low Power mode of the Bluephase G2 curing light. The cavity of tooth 47 was four millimetres deep and the cavity of tooth 46 was three millimetres
deep. Using the bulk fill technique, I was able to fill both cavities with a single increment each. I chose this procedure deliberately. The patient’s right temporomandibular joint was dislocated due to an accident and she could open her mouth only to a limited extent. If she had been required to keep her mouth open for too long, she would have incurred considerable pain in the
mandibular joint. The option to use a fast and yet reliable filling technique (bulk fill) proved to be the ideal route.
For sculpting the composite (shade IVA), I used an Optra - Sculpt instrument. The composite was polymerized at a low intensity to achieve an optimum marginal seal between the natural tooth structure and restorative. This assisted in mitigating the effects of composite shrinkage. Each restoration was cured for 20 seconds using the Low Power mode (Bluephase G2) and then any excess composite material was removed with fine-grit diamond burs. After removal of the rubber dam, the occlusal characteristics were adjusted and the restoration was polished with Astropol discs, Astropol silicone tips and Astrobrush brushes.
Second patient case
This 17-year-old male patient showed extensive cervical caries in the posterior region. The buccal surfaces of all teeth were affected by tooth decay. Additionally, caries was detected on the lingual surfaces of teeth 37, 36, 35, 34 and 33. The patient was generally in good health and he practiced appropriate oral hygiene at home. In an extensive consultation with the youngster we learned that he consumed large quantities of soda drinks every day. It was his high-acid diet that caused the caries and demineralisation of
his teeth. Following a motivational and therapeutic phase including the use of mouth rinses and fluoridated toothpaste, the patient gradually changed his dietary habits.
The carious lesions were to be restored with composite. For this purpose, the decayed tooth structure was removed and the cavities were rinsed with 2 per cent chlorhexidine digluconate solution. Similar to the first case, Total Etch gel was applied first, followed by ExciTE F adhesive. In this case too, the aim
was to fill each cavity with a single increment. In order to achieve this, I
selected again the bulk fill composite Tetric EvoCeram Bulk Fill (shade IVA),
which affords a reliable but fast filling technique that is comfortable for the
patient. I contoured the composite with OptraSculpt instruments and light-cured each restoration for 20 seconds in the Low Power mode (Bluephase G2). After removal of excess material, high-gloss polishing with Astropol discs, Astropol silicone tips and Astrobrush brushes was performed. At the
recall visit six months later, the patient’s oral situation was healthy and stable.
Conclusion
A “single-increment filling” technique with this new generation of composite materials (Tetric EvoCeram Bulk Fill) provides a fast route to restorations with mechanical and esthetic properties similar to those of conventional composites. The simplified procedure increases the treatment comfort for the patient and
clinician.