In many clinical situations, composite restorations offer advantages over all-ceramic restorations. The treatment is less costly, usually less invasive, and the restorations can be modified and repaired at any time. When it comes to restoring multiple teeth, however, a free-hand layering approach used to build up every tooth separately can be very time-consuming and labour-intensive. In these situations, the flowable injection technique –also referred as injection moulding – is a great alternative. It is minimally invasive, suitable as a temporary or permanent solution to issues around tooth wear and irregular shape, and time-efficient in the clinical setting.
While the planning phase including the creation of the wax-up can be accomplished in the traditional way or in the digital workflow and components may differ depending on the preferred way of working, two materials are essential for the implementation of the flowable injection technique: A transparent silicone and a flowable composite. The silicone is used to produce an index and transfer the planned shape of the restorations from the wax-up into the patient’s mouth. Transparency is needed to make sure that the flowable composite will be cured properly through it – an important precondition for high-quality results. The flowable composite is injected into the silicone index. While offering a great flow behavior during injection, the selected material should also exhibit a high mechanical stability for durability. CLEARFIL MAJESTY™ ES Flow (Kuraray Noritake Dental Inc.) offers the desired properties. One possible way to combine the materials and implement the technique is illustrated using the following patient case.
This patient came to the dental office after orthodontic treatment with a request to improve the aesthetics of her smile. In the maxillary and mandibular anterior region (incisors and canines), severe tooth wear was diagnosed, with the maxillary central incisors most severely affected (figs. 1 to 4). To restore her maxillary teeth as quickly as possible, the least invasive immediate treatment option was selected: A smile makeover with composite using the flowable injection technique. In the long term, it is planned to perform a full-mouth rehabilitation with all-ceramic restorations.
Fig. 1. Initial situation: Lateral view from the right.
Fig. 2. Initial situation: Lateral view from the left.
Fig. 3. Initial situation: Frontal view.
Fig. 4. Close-up of the severely worn central incisors.
After an analysis of the tooth color using two different methods (figs. 5 and 6), a digital impression was taken and a wax-up designed with dedicated CAD software. The wax-up model was then printed (fig. 7); it served as the basis for the production of the transparent silicone index (figs. 8 and 9). After complete curing of the material, injection channels were integrated at the incisal edges of each tooth to be restored.
Fig. 5. Determination of the tooth colour using a shade guide.
Fig. 6. Picture taken with a white_balance grey reference card for objective shade quantification.
Fig. 7. 3D-printed model of the upper jaw with the virtually designed wax-up.
Fig. 8. Silicone index produced over the wax-up model with injection channels at the incisal edges of each tooth.
Fig. 9. Close-up view of the index with injection channels.
To validate the selected shade, small amounts of composite (buttons) in three different shades were applied to the untreated surface of the left central incisor and cured (fig. 10). In this way, it is possible to visualize the color of the composites in the mouth. The selected shade was A1. The aprismatic enamel layer on the surfaces of the six maxillary anterior teeth was carefully removed with burs to create ideal bonding conditions (fig. 11). The teeth were then isolated with clear matrix strips for the implementation of the bonding protocol on the right canine and central incisor and left lateral incisor: To provide for proper interproximal separation and contacts, it is advisable to treat every other tooth and then repeat the procedure for the rest. The teeth were etched with phosphoric acid, rinsed and carefully dried before applying the selected adhesive (CLEARFIL™ SE PROTECT, Kuraray Noritake Dental Inc.) (fig. 12). For separation and protection of the adjacent teeth during composite injection, PTFE tape is a great choice (fig. 13).
Fig. 10. Composite buttons applied to the left central incisor for shade validation.
Fig. 11. Roughened tooth surfaces.
Fig. 12. Etched and bonded surfaces of the right canine, right central incisor and left lateral incisor after isolation with clear matrix strips.
Fig. 13. Protection of the adjacent teeth with PTFE tape.
After its application, the silicone index was placed in the mouth and CLEARFIL MAJESTY™ ES Flow in the shade A1 injected tooth by tooth through the injection channels (fig. 14). What followed was proper light curing of the composite through the index. The situation after index removal is shown in figure 15. At this stage, the excess still needed to be removed, before protecting and separating the already restored teeth with PTFE tape and repeating the procedure for the other lateral incisor, central incisor and canine.
Fig. 14. Index with injected composite.
Fig. 15. Result after index removal.
Once all the excess material was completely removed, the occlusion was checked and adjusted. The immediate treatment outcome is shown in figures 16 to 18, while figures 19 and 20 were taken at a recall after six months.
Fig. 16. Treatment outcome: Frontal view.
Fig. 17. The new smile.
Fig. 18. Treatment outcome: Occlusal view.
Fig. 19. Appearance of the teeth…
Fig. 20. … at the six-month recall.
Thanks to advances in restorative materials and technological tools, it is nowadays possible to restore our patients’ smiles quickly and reproducibly. The flowable injection technique is one of the most successful examples of modern aesthetic treatments using composite resin. CLEARFIL MAJESTY™ ES Flow has all the qualities needed to carry out these treatments under the right conditions.
Dr. Adrien Lavenant obtained his degree in Dentistry from Aix-Marseille University in 2010. He pursued post-university training in periodontology, implantology, and restorative and aesthetic dentistry (Aix-Marseille University and Paris). Dr. Lavenant has been a former teaching staff member at Aix-Marseille University since 2011 and continues to teach in the postgraduate programme in restorative and aesthetic dentistry. He practices in his private clinic in Aix-en-Provence, specializing in restorative, prosthetic, and aesthetic implant dentistry. He has been a member of the international Bio-Emulation group since 2019 and shares his patient care philosophy in accordance with the principles of biomimetic dentistry.
