Case background

Fig. 1: Reference photograph taken with a 18% neutral grey card.

A 55-year-old female patient with a medical history of controlled hypertension presented to the practice for tooth whitening. It was foreseen that dental bleaching would not have an effect on the shade of a pre-existing porcelain veneer on tooth #12, and that this would need to be retreated after the procedure, especially if the shade value changes were significant. The patient started with a baseline shade of VITA 1M1:2M1 in a 50:50 ratio in the maxillary anterior region and of VITA 1M1 in the mandibular anterior region. After a night guard bleaching protocol with 10% carbamide peroxide worn overnight for three to four weeks, the patient succeeded in achieving a VITA Shade 0M3 in both arches. As a result, there was a significant value discrepancy between the veneered tooth #12 and the adjacent teeth and also increased chroma noted on the contralateral tooth #22 owing to a facially involved Class III composite restoration. Tooth #22 also did not match the contralateral tooth in dimension, and thus the decision was made to treat both lateral incisors with bonded lithium disilicate laminate veneers. The adjacent canine (tooth #23) featured localised mild to moderate cusp tip attrition, but the patient did not want to address this until after the recommended veneers had been placed. The goal of smile design at this stage was to establish bilateral harmony with a view to placing an additional indirect restoration to restore the facial volume and address the cusp tip deficiency of tooth #23 in the near future.

Procedure

A digital smile design protocol was not required for the initial intention, which was individual treatment of the lateral incisors, as slight variation is permitted in this tooth type, being a personality and gender marker of the smile. Prior to anaesthesia, the target shade was selected using retracted photographs featuring both polarised and unpolarised selections. The photographs were prepared for digital shade calibration by taking reference views with an 18% neutral grey–white balance card (Fig. 1).

The basic body shade was VITA 0M2 with an ingot shade of BL2. The patient was anaesthetised using 1.5 carpules of a 2% lignocaine solution with 1:100,000 adrenaline before affixing a dental dam in a split-dam orientation. The veneer on tooth #12 was sectioned and removed and a minimally invasive veneer preparation completed on tooth #22 (Fig. 2). Partial replacement of the old composite resin restoration was completed on the mesio-inciso-buccopalatal aspect of tooth #12 and the intact segment maintained. Adhesion to old composite was achieved using both microparticle abrasion and a 10-MDP-containing silane coupling agent (CLEARFIL CERAMIC PRIMER PLUS, Kuraray Noritake Dental). The margins were refined, and retraction cord was soaked in an aluminium chloride solution and packed. The preparation stump shades were recorded. The final impressions were taken using both light- and heavy-bodied polyvinylsiloxane in a metal tray. The patient was provisionalised and sent away with instructions to verify the shade at the laboratory at the bisque bake stage. The models prepared by the laboratory verified the minimally invasive nature of the case.

Fig. 7: Excess cement removal after tack polymerisation for 1 second.

The cement was rendered into a gel state, which facilitated clumping or en masse removal of cement, requiring minimal clean-up (Fig. 7). The margins were coated using a clear glycerine gel prior to final polymerisation to eliminate the oxygen inhibition layer (Fig. 8). The margins were finished and polished to a high shine and the occlusion of the restorations verified. The postoperative views showed excellent aesthetic marginal integration (Fig. 9). On polarised photograph reassessment, the restorations were found to be well integrated into the new smile aesthetically and functionally (Fig. 10), and aesthetic augmentation of tooth #23 to match the contralateral canine was awaited.