By Dr Ralph Schönemann
The direct restoration of multiple defects, particularly old restorations with secondary caries, places considerable demands on both the clinician and materials used.
Compared with indirect fabricated restorations, the effort is considerably less. Generally, these materials require a temporary restoration as well as a second treatment session following conventional impression-taking.
The automated fabrication of individual full ceramic restorations after optical scanning is the single-appointment alternative, however, it requires investment in this technology.
A prerequisite for successful, direct preparation of restorations with purely light-curing composite materials in the layering technique is avoiding tension during volumetric shrinkage which occurs during polymerisation.
The adhesives and hybrid composites should be compatible with each other and offer good long-term performance. This is reflected both in in-vitro tests as well as in in-vivo long-term studies.
One of the requirements for state-of-the-art adhesives and composites is safe handling during the preparation of the restoration. This implies a good, uniform wetting layer when applying the adhesive and convenient modelling properties of the hybrid composite which allow the clinician safe adaptation to the bonded tooth.
On top of it, the filler composition should be able to achieve an impressive gloss of the surface during preparation and polishing.
Lastly, the result achieved with the composite in terms of colour, gloss, and abrasion has to be reliable in the long term. This result is complemented by a technically reliable adhesive through permanent impermeability of the restoration margins.
The practical implementation of a direct restoration, combining adhesive and composite, and an evaluation of the prerequisite material requirements, are discussed in the following case study.
In this case, intraoral examination revealed insufficient tooth restorations on the lower posterior left quadrant (Fig. 1). The restoration margins revealed leakage and discolouration. The gap closure between the teeth 35 and 37 was particularly irritating for the patient. The x-ray image (Fig. 2) revealed secondary caries and the approximal situation.
The teeth involved were cleaned, as were the adjacent teeth, while waiting for block anaesthesia to come into effect. The placed Flexi Dam permitted a good overview and provided good conditions for drying the work area, allowing permanent adhesive bond between tooth and restoration.
The old restorations were removed entirely and the secondary caries was excavated (Fig. 3). ONE COAT 7 UNIVERSAL was used as adhesive.
ONE COAT 7 UNIVERSAL is an MDP-based, light-curing single component bonding agent which can be applied in self-etching, selective etching or total etch techniques. The tooth surface was conditioned with Etchant Gel S and polymerised with an S.P.E.C. 3
LED lamp (Fig. 4).
After excavation of the secondary caries, the cavity floor of tooth 35 was revealed to be in close proximity to the pulp chamber. Pulp-conserving acid conditioning was indicated. Selective etching of the enamel with Etchant Gel S for 30 seconds was followed by a shortened Total Etch for 10 seconds (Fig. 5).
Then, the etchant was removed thoroughly by rinsing for 20 seconds and the cavities were dried with care. Immediately afterwards, ONE COAT 7 UNIVERSAL was applied with a brush to maintain adequate moisture and provide complete cover prior to placing the matrix (Fig. 6). The adhesive is gently flushed with an air blower and polymerised with the S.P.E.C. 3 LED lamp for
A variety of partial matrix systems are available for a sophisticated design of the approximal surfaces. Here, we used a ROEKO tension-free steel matrix band and trimmed it to the desired length as a partial matrix. This band is available in different widths and material strengths.
The nonelastic properties of the material make anatomical customisation extremely easy. The thickness of the band in the area of the contact point can be minimised effectively by thinning.
Fixation and basal sealing of the trimmed partial matrix was performed with a wooden wedge, and for lateral sealing, the band edges were pressed to the tooth surface using a clamping ring.
The design of the approximal surfaces (Fig. 7) with BRILLIANT EverGlow A3/D3 (Fig. 8) is simple. The material keeps its shape and does not stick to the instrument. Coated instruments are of advantage here, in fact, filling instruments work better.
There are no limits to creating the morphology of the occlusal surfaces as the consistency of BRILLIANT EverGlow offers excellent
modelling properties. Delicately modelled fissures (for example, using an endo needle) remain open and do not merge again, customisation is truly enjoyable with this material.
After removing the matrix, the approximal surface was given a spherical design using an EVA file, any bonding expressed basally from the matrix was removed, and the transition from the tooth to the restoration was brought to the same level.
The matrix was applied distally to premolar 35 and sealed basally with a wooden wedge; and laterally with a clamping ring. ONE COAT 7 UNIVERSAL was applied and gently air-cleaned after an exposure time of 20 seconds.
ONE COAT 7 UNIVERSAL was polymerised with the S.P.E.C. 3 LED lamp for 10 seconds (Fig. 9). The matrix, which has now been stabilised by bonding, was thinned out swiftly using a zirconium round burr in anti-clockwise rotation, yet without water.
At the same time, the partial matrix must be reliably fixated by the wooden wedge. Metal chips were avoided by using anti-clockwise rotation. Any metal chips that may still be generated, are dispersed with air.
The desired result is a tight, spherical contact. Approximal convexity can be customised easily in this manner.
This was followed by designing the approximal surface with BRILLIANT EverGlow A3/D3 as well as the anatomical morphology of the occlusal surface. Due to the well-sealed partial matrix aided by the clamping ring, the finishing effort required after their removal is minimal.
Using the EVA file, the result is already satisfactory (Fig. 10). An occlusal check and minor corrections were performed.
Polishing takes little time as BRILLIANT EverGlow delivers its gloss quickly (Fig. 11). Then, the restorations are brought to a high gloss using an occlubrush. In their final from, the restorations are more than satisfactory (Fig. 12).
The applied layer method of the BRILLIANT EverGlow submicron filled hybrid composite in combination with the ONE COAT 7 UNIVERSAL adhesive delivers very good results. The S.P.E.C. 3 LED polymerisation lamp provides reliable curing of both restoration materials at high conversion.
Sticks the way it should, to the tooth and not the instrument. Due to the consistency-setting of the dental restoration material such as BRILLIANT EverGlow, application is easy and results in anatomically correct outcomes.
Submicron hybrid composites offer an impressive rapid and consistent gloss. Appropriate shades and an easy to achieve gloss due to intelligent filler design provide the desired and sustainable aesthetics.
Permanent protection against leakage in the marginal region. The high density and composition of the filler particles of the BRILLIANT EverGlow composite optimise the results in terms of reducing shrinkage and the resulting lower shrinkage stress.
The clinical long-term objective of sealed restoration margins can be achieved with even greater certainty when using a reliable adhesive such as ONE COAT 7 UNIVERSAL.
About the Author
Dr Ralph Schönemann is a practicing dentist from Augsburg, Germany. His dental practice offers range of services such as metal-free restorations, implantology and oral surgery, child treatment, and aesthetic dentistry.
This article was published in Dental Asia March/April 2021 issue.