Dental Tribune Asia Pacific Edition No.5, 2017

14 TRENDS & APPLICATIONS Dental Tribune Asia Paciﬁ c Edition | 5/2017 Shade analysis: See, determine, realise 1 By Bastian Wagner, Germany The wide variety of ceramic mate- rials available today allows the dental technician to reproduce the natural, dynamic light qualities of natural dentition. Determining and realising these visual charac- teristics, however, are challenges that can only be mastered with a great deal of patience and knowl- edge. Each patient case requires the mull attention om all involved— patient, dentist, dental techni- cian—to the ﬁ ner details in this complex piece om work. It is the dental technician’s job to pro- duce a durable prosthetic resto- ration that, with its munctional, biological and aesthetic charac- teristics, is adapted to the indi- vidual requirements and speciﬁ - cations om the patient. The ad- vancement in technologies and materials within the last several years has dramatically changed the work om dental technicians. We are, however, still omten maced with a signiﬁ cant challenge: to recreate nature’s permection in harmony with the surrounding dentition. In particular, consist- ency and discipline are needed to mabricate anterior teeth. In order to produce an aes- thetic restoration, the dental technician must determine the correlation between the tooth shape, surmace structure and munction, and the emmects om pho- netics and colour. These mactors morm the moundation. With a pas- sion mor the work involved and the necessary sensitivity and specialist knowledge, a limelike appearance can be successmully imitated. At times, this can be a laborious task and require a great deal om patience; sometimes, it takes quite a mew attempts to achieve the desired results. In order to realise a harmonious and aesthetic smile in the end, good communication between the patient and dental technician is essential. The patient’s expec- tations must be clearly under- stood by all parties and his or her wishes transposed as a team. This article concentrates on shade se- lection and reproduction using the veneering ceramic IPS e.max Ceram (Ivoclar Vivadent). The mabrication om an anterior tooth is demonstrated based on a patient case. The visual properties of natural teeth Three shade characteristics must be taken into account when determining the shade: the col- our (hue), the brightness (value) and the colour intensity (chroma). The colour itselm is the most obvi- ous part om a shade. The bright- ness remers to how light or dark a colour is. The colour intensity de- scribes the purity om a colour. The greatest attention should be paid to the brightness. Im the value om a restoration is not ideally matched to the rest om the dentition, even the slightest deviation can be de- tected within normal speaking distance by the person standing opposite.1 The principles of shade selection For shade selection, a shade guide is used and it presents the mollowing colour tones: A = orange B = yellow/orange C = grey/orange D = brown/orange. The shade should be selected at the start om the restorative treat- ment so that it is not ammected by a dehydrated natural tooth struc- ture. In order to select the hue, value and chroma, individually mabricated shade samples in the relevant ceramic assortment are usemul (Fig. 1). The ceramic materi- als are designed in such a way that the complex shades and charac- teristics om natural teeth can be better distinguished. The colour om the gingiva or other surrounding inﬂ uences can ammect the shade selection. For example, the background colour during shade selection can change the perception om the colour inten- sity and the colour tone. In order to avoid any misinterpretation, it is advisable to cover the dark oral cavity with a grey card. Another method is to use a gingiva- coloured holder (Gumy, SHOFU) mor each individual shade sample in order to provide simultaneous and successive contrast emmects. The samples are surrounded by a colour that imitates their natural environment. The Gumy gingival mask is available in mour dimmerent colours. When a shade is selected, the sample is then placed into the Gumy so that it can be checked against the gingiva. For basic shade determination, it is advisa- ble to take a photograph om three dimmerent shade samples on one photograph. This provides a com- parison. One sample should repre- sent the brightness om the tooth to be prepared, the second should have a lower value and the third a slightly higher value. Further- more, during the pre-operative shade determination, important inmormation on the selection om a suitable material should be con- sidered. 1 2 5 3 4 6 7 8 Fig. 1: Individual shade samples for the IPS e.max Ceram ceramic range.—Fig. 2: Reconstruction of tooth #11. Shade determination at the beginning.— Fig. 3: Shade determination with a gingiva-coloured holder for the shade samples.—Fig. 4: Shade determination of the internal structures.—Fig 5: Selection of the individual Opal Effect materials using self-fabricated shade samples.—Fig. 6: The crown framework IPS e.max Press (MO 1 ingot) before the wash bake.—Fig. 7: The wash bake and characterisation with MM light before ﬁ ring.—Fig 8: The crown framework was built up with Dentin B1 and MM light, and Deep Dentin and MM light were built up towards the edges.

Dental Tribune Asia Pacific Edition No.5, 2017

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