Planning the shade prescription.

When a patient comes in for a consultation for aesthetic treatment, the consultation appointment is divided into two. Firstly, a conventional evaluation with charting, periodontal, occlusal and radiographic surveys, diagnostic models and photographs is performed. Secondly, an aesthetic evaluation involving aesthetic analysis and a focus on the patient’s aesthetic requests is carried out. Media images displayed today have a very strong influence in contemporary dental treatment. Increasingly, today’s smile is part of a youthful dynamic appearance characterised by whiter teeth, which often fall beyond the range of traditional shade guides. To that effect it is possible to identify two types of patients: perfect-minded, or natural-minded. Patients in the first category will typically expect maximum regularity and alignment along with maximum brightness and a ‘general sparking effect’. Critical factors for these patients include a straight dental midline, a regular smile line, often flatter than the curvature of the lower lip, symmetric central incisors, lateral incisors and canines along with symmetric gingival margins (Figure 1). Natural-minded patients will typically expect a general sense of regularity and alignment along with definite brightness, but they do not wish their teeth to be noticed at every turn. In any pleasant smile, pleasing tooth symmetry is found close to the midline; therefore the central incisors must be mostly symmetric with only minor irregularities (a central incisor may be more mesially inclined than the other, and the distal incisal angle of the central incisors may be bilaterally asymmetric). The main asymmetry will be provided between the lateral incisors. The canines will also provide minor asymmetry as their gingival margins and their cusp tips do not need to be levelled horizontally. The depth of the incisal embrasures should be of a natural depth in addition to providing a natural progression (Figures 2 and 3). These pictures also illustrate the need to provide these patients with subtle polychromatic effects: incisal halo, streaks and increased cervical saturation. When planning the shade prescription, one must bear in mind that the most frequent shade variation from the basic shade of an anterior tooth is observed in nature at the incisal third. The next most frequent category observed is when the shade distribution is nearly uniform, resulting in a monochromatic appearance. In the third category, the colour deviation from the basic shade is observed at the cervical third mostly and finally in the fourth group, the shade variation involves the middle aspect of the tooth. To give the patient an idea of what incisal effects are possible, the incisal aspect of the shade tab is discussed with the patient after the basic shade is selected. The usual patients’ reaction is to prefer incisal effects similar to the shade tab if they are natural driven, and to attenuate the effects to the maximum if they are perfect-driven. There are three typical scenarios that can be transmitted to the dental ceramist: