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Dental Tribune Indian Edition

8 Dental Tribune Indian Edition - January 2013 Extending the boundaries of feasibility in direct restorative procedures A clinical case combining a high-performance material and clearly defined protocol Dr Gauthier Weisrock France Modern high-performance compo- site materials and standardised tre- atment protocols have led to more direct composite restorations being fabricated in the anterior region than ever. Even extremely challenging cases may now be treated chairside with predictable results and minimal loss of tooth structure. A 24-year-old female patient pre- sented at our practice with a request regarding aesthetics. She disliked the appearance of tooth #11, which sho- wed severe discolouration after endo- dontic treatment. A clinical examina- tion revealed that the root had been extirpated after an accident and that a fractured piece had been reattached with a composite material (Figs 1 & 2). Upon radiological examination, it was found that the root-canal treatment had been performed correctly. However, a post had not been used. Owing to the fact that approxima- tely half of the original tooth structu- re had been lost, we opted for a direct composite restoration, provided that a tooth-whitening procedure could be successfully completed. Along the spectrum of possible treatments, this approach is located between “conventional” composite restoration and ceramic veneering and, therefo- re, appeared to be clinically appro- priate. The patient, whose primary con- cerns were a natural tooth shade and minimal loss of tooth structure, agreed to the recommended proce- dure. We decided to use the nano- hybrid composite IPS Empress Direct (Ivoclar Vivadent) to fabricate the re- storations. In addition to dentine and enamel materials, this product is also available in an opalescent material version. Preliminary treatment First, internal bleaching was per- formed on the tooth, on which the success of treatment would depend. Access to the endodontic chamber was created through the old resto- ration. The gutta-percha increment was removed up to 3 mm below the cemento-dentinal junction. At the bottom of the cavity, a plug with a thickness of 2 mm made of glass io- nomer cement was inserted to prevent the bleaching agent from accessing the sensitive areas. We used a mixture of sodium perborate and distilled wa- ter for the bleaching procedure. The access to the cavity was then sealed with a temporary material. Since the desired tooth shade was not achieved upon initial bleaching, the entire procedure had to be repe- ated after one week. After another week, the result was finally optimal (Fig 3). In order to neutralise the bleaching agent, calcium hydroxide was placed into the cavity and left in place for at least one week. (An adhe- sive may only be applied 15 days after conclusion of the bleaching procedu- re, in order to ensure optimum adhe- sion and stable shade.) Aesthetic diagnosis and shade determination After tooth-shape analysis, we con- cluded that the proportions were har- monious compared with tooth #21. In order to avoid a misinterpretation of the shade owing to dry adjacent teeth, the tooth shade was determined prior to any intervention and in daylight. The IPS Empress Direct shade guide was used for the determination of the enamel and dentine materials. We de- termined the dentine shade based on the cervical third and the enamel ma- terial based on the incisal third of the adjacent tooth. Particular attention was paid to the anatomical structure of the adjacent tooth and the various opalescent reflections visible on the incisal surface, since it was our aim to imitate these features. A layering dia- gram detailing all the materials that we planned to use was prepared. In this case, only four shades were used: A3/A2 Dentin, A2 Enamel and Trans Opal. Subsequently, we created a palatal Fig. 1: Severely discoloured tooth#11.— Fig. 2: The shape of tooth #11 appeared to be harmonious with tooth #21. The sub- stance loss amounted to somewhat less than half of the tooth.—Fig. 3: After the bleaching procedure, the shade of tooth #11 was optimal.—Fig. 4: Prepared tooth #11 with vestibular chamfer and straight, right-angle palatal margin. Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 Fig. 5: Creating the palatal wall with enamel material (A2 Enamel).—Fig. 6: Designing the proximal area and the transition lines.—Fig. 7: Building up the palatal and proximal areas, or transforming a complex preparation into a simple one. Trends & Applications silicone key on tooth #11 with the ap- propriate shape and occlusion. Once in place intra-orally, this key helped to create the palatal wall of the resto- ration in one step. The key included the teeth adjacent to the tooth that needed to be restored and covered the incisal area. Preparation and applica- tion of the adhesive The existing restoration was remo- ved with the help of both rotary and ultrasonic instruments and with care to prevent any damage to the adjacent teeth. During the preparation of the tooth, the mechanical properties of the material used and the aesthetic integration needed to be taken into account. In the case of IPS Empress Direct, the ideal preparation design involved a vestibular chamfer and a straight, right-angle proximal and palatal margin (Fig. 4). Before proceeding with the adhe- sive cementation, it was necessary to protect the operatory field from saliva or blood in the oral cavity. Therefore, we isolated the anterior teeth, inclu- ding the canines, with a rubber dam. The expanded treatment area allowed us to assess the incisal line, and the size and shape of the adjacent teeth.