Preparation
In order to limit the loss of healthy tooth tissue while still creating sufficient room for the veneers, a preparation was chosen with an incisal reduction of 1.5 mm and a buccal reduction of 0.5 mm. A depth cutter—a diamond drill with 0.5 mm deep recesses—was used to achieve this (Fig. 2).

In order to adjust the shape of the midline to the new veneers, cutting was carried out centrally through the contact point. From the distal aspect, the cutting was stopped before the contact point. The thin shoulder was laid equi-gingivally, so that a dry operative field could be achieved without damage to the gingiva.

The preparations were then finished using fine diamond drills and polishing discs. The existing, properly bonded composite restorations were left in situ (Fig. 3).

Since the transparent veneers were very thin, the colour of the cut teeth was significant. The colour was therefore determined using the natural dye colour ring (Fig. 4). Finally, impressions were taken. Temporary restorations were attached by means of four small etching points and bonding.

Cementation
In order to combine superior aesthetics with adequate strength, pressed lithium disilicate restorations were chosen and these were veneered buccally. Prior to cementing the veneers, they were tried for size and checked for marginal integrity, contact points, occlusion/articulation and aesthetics. Thereafter, the correct cement shade was established by testing the various try-in paste shades underneath the veneers; Universal (Shade A2) appeared to be the most appropriate shade in this case. The teeth were then polished with pumice and the veneers were cleaned with alcohol, after which teeth #14–24 were isolated by a rubber dam. An incisor clamp was placed on the first tooth to be cemented. The veneer was tried for size once more to ensure that the rubber dam or the clamp did not interfere and that the operative field was completely dry (Fig. 5).

The veneer was etched with 9% hydrogen fluoride (Fig. 6) for 20 seconds to achieve micromechanical retention. It was then rinsed with water for 20 seconds before being neutralised in a solution containing ceramic neutralising powder. CLEARFIL CERAMIC PRIMER PLUS (Kuraray Noritake) was then applied to the veneer. This ensures chemical bonding between the veneer and the composite cement owing to the incorporated silane and MDP. The neighbouring teeth were separated by means of a transparent strip, after which the preparation was etched with 35% phosphoric acid (Fig. 7). PANAVIA V5 Tooth Primer (Kuraray Noritake) was applied after thorough rinsing with water and blown dry after it had taken effect for 20 seconds.

A thin layer of PANAVIA V5 cement (Kuraray Noritake) was then applied to the veneer. The veneer was placed on the preparation with the application of light finger pressure. A micro-brush was used to remove the major excess along the margins. The cement at the buccal and palatal aspects was light cured for 5 seconds. A sharp scaler and floss were used to remove any remaining excess, and glycerine gel was then applied to the edges to prevent the formation of an oxygen inhibition layer during curing. The cement was finally light cured on both sides for 20 seconds, the glycerine gel was rinsed away and the edges were finished by means of composite polishers. After placement of the first veneer, the rubber dam clamp was moved to the neighbouring tooth so that the cementing of the second veneer could proceed. This veneer was once more tried for size, pretreated and cemented in an identical manner (Fig. 8).

Treatment outcome
The veneers were checked a few weeks later (Fig. 9). The patient was very satisfied with the aesthetics of his two central incisors. The transitions from tooth to restoration were invisible and the gingiva was healthy. The transparency, surface structure and shine appeared better adapted to the neighbouring teeth and to the patient’s smile (Fig. 10).

About the author
Dr Paul de Kok studied dentistry at the Academic Centre for Dentistry Amsterdam (ACTA) and is a certified prosthodonist at the Kliniek voor Parodontologie Amsterdam [Amsterdam periodontics clinic], where he treats referred patients with restorative and aesthetic issues. In addition, he teaches indirect restorative dentistry at the Department of Oral Function at ACTA, as well as conducts research in the department of Dental Materials Science. He also delivers lectures on this field at both national and international levels.

Ceramist: Eric van der Winden, Oral Design Center Holland