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28 CAD/CAM Dental Tribune Middle East & Africa Edition | 3/2017 The Minimal Invasive Smart Smile Design By Asst. Prof. Dr. Cagdas Kislaoglu, Turkey We live in an era where patients are becoming more specific about how they would like their anterior teeth to be restored. Not only they are requesting an aesthetic solution to their dental problems, but they are also seeking procedures that will have a limited effect on the remain- ing tooth structures. Porcelain Lami- nate Veneers are one of the most conservative and aesthetic tech- niques that we can apply. The life span of the veneers is long and they are durable, especially if the right in- dications are chosen and the correct techniques are applied. The most im- portant thing is the conservation of sound tooth structure, so we should limit our preparations on enamel. When we limit our preparations on enamel, the tooth will not flex and it will stay as rigid as a tooth can be. Even if our preparation line passes through the dentin enamel junction margin and enters into dentin, mi- nor invasions won’t create a major problem. However, if the finished preparation is in contact with large amounts of dentin, this will create complex bonding issues with the dentin and will also increase the flex- ing factor on the tooth structure. If a tooth, which has been aggressively prepared and is more flexible as a re- sult, is subjected to different occlusal forces and keeps on flexing, the lut- ing resin at the margin will start coming off slowly and this situation will result in micro leakage or even de-lamination. Analysing The Smile In order to understand and visualise the desired outcome clearly and to produce the final smile design, the existing smile should be analysed carefully, using a 3-dimensional view. We should follow a photo and video protocol (Fig. 1). Facial view When we analyze the smile using a facial view, we see the mesiodistal and vertical problems. We can also Fig 1 Fig 2a Fig 2b Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 Fig 8 Fig 9 Fig 10 see the midline, the occlusal plane and the length and axes of the incisal teeth and can determine the desired future smile curve and the length of the future incisors (Fig. 2). 45-degree-angle view This angle gives us the opportunity to check the buccal-lingual position of the teeth and their crowding. It also gives us an idea of how the lips are supported by the teeth (Fig. 3). The view according to the lip This view can determine the buccal- lingual position of the teeth from a different angle (Fig. 4). Digital Scan of the Upper and Lower Jaw This gives us a chance to observe all aspects of the teeth in different an- gles from a 3-dimensional viewpoint (Fig. 5). Treatment Planning with Digital Wax Mock-Up The digital scan of the patient is opened in software that can produce a wax-up digitally. In order to en- hance each patient’s facial features and create a pleasing restoration, harmony in the size, shape and ar- rangement of the teeth is required. The dentist designs the new wax- up digitally and can also use pre- existing teeth templates from the software; this helps to speed up the digital wax-up (Fig. 6). The finalised digital mock up is print- ed as a 3-dimensional acrylic model (Fig. 7). A silicone impression is taken from this model and this will be used as a silicone index (Fig. 8). Aesthetic Communication with the Patient with the Acrylic Template The dentist should be able to under- stand all the signals coming from the patient, whether verbal or non- verbal. Using all these signals, the dentist designs the digital wax-up, so that the design can be tried in the mouth. The silicone index - made from the digital wax-up model to in- dicate the final contours of the teeth - is placed over the dental arch in or- der to allow the visualisation of the existing positions of those teeth on the dental arch, relative to the final outcome of the wax up and veneers (Fig. 9). The lip support of these resto- rations and the aesthetic length can be easily evaluated and should be ap- proved by the patient. Also, we want to evaluate the functional move- ments of the patient to see whether the design would create an anterior construction or not. The patient can easily look at the new smile design in the mouth and will be able to deter- mine what he/she likes and dislikes. At this stage, minor changes can be made to the acrylic . If the patient wants longer teeth, free-hand com- posite can be added to the existing acrylic template to make the teeth longer. If the patient wants shorter teeth, the teeth can be shortened and arranged to the length the patient wants, using a composite shaping disc. In rare cases, we cannot satisfy the patient and we spend hours on the design . This is not because the dentist does not know his job, but because the patient does not know what he wants. The ability to say no to such patients will save the dentist many sleepless nights! If the aes- thetic dentist and patient find it dif- ficult to agree on the objectives, it is in the best interests of everyone not to begin the treatment. Since, by us- ing this additive technique, you have not touched the sound tooth struc- ture, you can easily consider not go- ing on with the case. But, as I said, this kind of case is very rare. Most of the patients are very happy with the design in the mouth. Then, a suitable tooth shade is chosen and we go on to the next step. Tooth Preparation Through the Acrylic The beauty of these Aesthetic Acrylic teeth is that, besides the evaluation of the aesthetic functions and pho- netic aspects, we have a great tool in our hands now to prepare the teeth. Since this Acrylic resembles the exact final contours of the final outcome, such as the incisal-edge position and the facial contours of the teeth, now ÿPage 30