Class IV restoration with direct composite resin

Anthony Mak and Andrew Chio present a case study using the layering-stratification technique with the G-aenial A’chord composite system.

The concept of layering or stratification of direct composite restorations combines optical properties from the different resin layers with the aim of emulating the colour, characteristics and translucency of the natural dentition.

Progressive improvements in composite resin technologies have led to the simplification of this treatment procedure that is commonly perceived as complex. However, difficulties exist in mimicking the remaining tooth structure when restoring teeth in the anterior segment of the dentition because of the variety of shades, chroma, and translucency levels of many current composite resin systems.

New G-aenial A’chord (GC Europe) represents the evolution of the G-aenial system. This has been used in dental practices worldwide for more than 10 years. Compared to its predecessor, G-aenial A’chord provides an upgrade from the original G-aenial system in these aspects:

Beautiful and harmonious under any light with a natural fluorescence
Optimal handling properties, allowing for the material to be easily sculpted with instruments or brushed with restorative brushes
Full-coverage silane coating (FSC) covers the individual filler particles to prevent chipping at the margins, so giving better wear properties with high gloss retention
The incorporation of additional opaque and enamel shades allows an infinite range of opacity and value possibilities
Simplification with five core shades that cover all 16 Vita shades.

Case report

Figure 1: Preoperative unretracted view, illustrating the unaesthetic and failing direct composite restoration on the upper left central incisor (UL1)
Figure 2a: Preoperative retracted with regular flash
Figure 2b: Preoperative retracted with polarised filter
Figure 3: The working field was isolated with the use of rubber dam. The existing restoration and caries were removed and a 2mm bevel prepared on the labial margin of the preparation to facilitate the aesthetic and functional integration of the restoration to the remaining natural tooth structure
Figure 4: The bevel was prepared and finished with a tapered diamond bur. All the transition angles of the cavity were rounded with an oval- or egg-shaped polishing diamond bur. The burs form part of the Dr Anthony Mak Custom C&B Selection kit from Komet Dental
Figure 5: The palatal stent was trimmed and tried-in to verify the fit of the silicone matrix and to ensure the absence of any interferences to its seating from the rubber dam and clamps
Figure 6: The cavity was lightly air abraded with a 29-micron aluminium oxide powder Aquacare prior to the adhesive procedure and Teflon (PTFE) tape was utilised to prevent the inadvertent bonding to the adjacent teeth
Figure 7: The adhesive procedure commenced with the cavity selectively etched with 37% phosphoric acid gel Ultra-Etch (Ultradent). The etching gel was rinsed away and the adhesive protocol was completed by the application of a universal bonding agent, G-Premio Bond (GC Europe). The universal bonding agent was then air dried for five seconds with maximum air pressure and light-cured for 10 seconds according to the manufacturer’s instructions
Figure 8: Following the adhesive protocol, a thin layer of semi-translucent enamel, G-aenial A’chord shade JE (Junior Enamel, GC Europe), was used to create the palatal shell

The following case study demonstrates the use of the G-aenial A’chord direct composite system in the restoration of a complex class IV in a 22-year-old female patient.

The patient presented to the practice relaying her dissatisfaction of an existing restoration on her upper left central incisor (UL1). She requested its replacement with a new restoration that was conservative and ‘invisible’ when she smiled or engaged in conversation. She also relayed that the existing class IV restoration had been done four times by her previous dentist without an outcome or result that was satisfactory to her.

Clinical examination revealed a high smile-line with a symmetrical and aesthetic gingival architecture. The existing composite restoration on the UL1, while clinically acceptable, did not integrate with the shade of the tooth and to the other teeth in her dentition.

The discolouration and minor ledging on the disto-labial aspect of the existing restoration also indicated the likelihood of marginal leakage in the region.

The preoperative colour assessment showed that the UL1 was slightly more chromatic than the adjacent UR1. The UL1 also exhibited a very slight labial displacement in its alignment compared to the adjacent UR1.

Figure 9: The interproximal wall was completed utilising the same semi-translucent enamel shade, G-aenial A’chord shade JE. The interproximal wall was formed with the use of a plastic myeloid strip and pull through technique to help develop an anatomical contour
Figure 10: The dentine layer was then completed by the application of an opaque shade, G-aenial A’chord shade AO2 (Internal Opaque Dentine, GC Europe). This increment was shaped to emulate the extensions of natural dentine core morphology and was extended just slightly short the prepared bevel. The dentine or opaque shade provides the correct opacity to the final restoration
Figure 11: A chromatic body shade, G-aenial A’chord shade A2 (GC Europe) was then applied and extended beyond the bevel to mask the transition line. Internal anatomy (ie, mamelons) in the incisal third was also sculped and formed in this increment of composite resin
Figure 12: White tints, Essentia White Modifier (WM) (GC Europe) was used to accentuate the mamelons and to replicate the similar characteristics and features present in the adjacent right central incisor (UR1). Comparisons to the polarised diagnostic images taken prior to commencement of the restoration provided a reference for the incorporation of these internal features
Figure 13: A final translucent shade of G-aenial A’chord shade JE was then layered to bring the anatomy to full contour and to achieve a natural optical blending effect
Figures 14a and 14b: Glycerine gel was applied over the buccal surface of the restoration and light-cured to maximise the polymerisation of the layered direct composite restoration due to the absence of the oxygen-inhibition layer
Figure 15: The restoration was polished and finished to incorporate the anatomy to produce a lifelike restoration that mirrored the UR1
Figure 16: The polishing and finishing protocol employed the use of abrasive discs (Sof-Lex), polishing diamond burs, followed a graded sequence of silicone polishers and finishers (Astropol). The restoration was then completed using a Diapolisher paste on a felt-buff (Flexi-Buff) to recreate the gloss of natural enamel

The patient’s health history was unremarkable. Radiographic and periodontal examination showed that the UL1 demonstrated no pathology or issues requiring intervention prior to the commencement of the restoration. The UL1 exhibited a normal response when the vitality was thermally tested.

The treatment options were discussed with the patient and the advantages and disadvantages of each were carefully identified. The options presented were:

A single reductive ceramic veneer on UL1
A full surface composite veneer on the UL1. The patient was advised that due to the slight labial displacement of the UL1, a very small labial reduction would be required to allow the space to mask the chromatic dentine
A conservative class IV on the UL1 to be completed additively to minimise any preparation and reduction of the natural tooth structure.

She preferred the conservative approach to her treatment involving an additive protocol (last option). She relayed that she would be happy with a harmonious composite restoration on the UL1. She did not feel that the slightly chromatic UL1 would be an aesthetic concern for her.

From the clinician’s perspective, the final plan and goal of the treatment was to restore the UL1 with a durable and long-lasting conservative direct composite restoration with a final result that is biomimetic with optimal aesthetic and morphological integration with her existing natural dentition.

Figure 17: Immediate postoperative (unretracted). The finished and polished G-aenial A’chord restoration demonstrates the morphological and optical aesthetic integration of the completed restoration to the existing natural dentition
Figure 18a: Immediate postoperative (retracted) with regular flash
Figure 18b: Immediate postoperative (retracted) with polarised filter
Figure 19: Two-week review demonstrating the complete optical and functional G-aenial A’chord restoration on the UL1
Figure 20: Two-week review demonstrating the complete optical and functional G-aenial A’chord on the UL1

Step by step

Prior to the restorative process, diagnostic images and the selection of the estimated shade was completed. Diagnostic impressions were also taken to allow the fabrication of a silicone palatal stent or matrix that would facilitate the 3D blueprint for the layering of the composite increments.

Conclusion

Developments in single shaded universal composite systems for the anterior dentition continue to improve and advanced layering techniques for anterior direct composite restoration will always be necessary in the contemporary aesthetic dental practice. This is due to the intrinsic anatomy of the natural tooth where the emulation of the optical and morphological properties cannot be achieved by a single mass of restorative material.

The G-aenial A’chord composite system has a simplified approach to the shading/layering process while providing a final result that is biomimetic, aesthetic and long-lasting.

This article first appeared in Clinical Dentistry magazine. You can read the latest issue here.

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Class IV restoration with direct composite resin

Case report

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