Fixed Restorations. Irena Sailer
concave
■ Midline
■ Interpupillary line
Smile aspect to be evaluated
■ Lip line – gummy smile, high, average, or low lip line
■ Vertical position of the incisal edges in relation to the face and the lip line
■ Horizontal position of the incisal edges in relation to the interpupillary line
■ Position of the dental midline in relation to the facial midline – potential midline shift
■ Angulations of the dental midline in relation to the facial midline and the interpupillary line
■ Outline of the incisal edges – straight, positive curve, negative curve
■ Exposure of posterior teeth
■ Buccal corridor
Tooth-related aspect to be evaluated
■ General shape of the clinical crown – square, ovoid, tapered
■ Size of the clinical crown – height, width, and the relation between height and width
■ Intratooth relation – size of the lateral incisor in relation to the central incisor and size of the canine in relation to the central and lateral incisors
■ Incisal edges steps
■ Tooth color – hue, value, chroma
■ Surface texture – smooth, pronounced
■ Characterization of the crown – translucency, spots, microcracks
Soft-tissue-related aspects to be evaluated
■ Position and curvature of the facial soft tissue
■ Soft tissue color and texture
■ Papillae – intact, reduced papilla height, missing, hyperplastic
After having evaluated these aspects clinically and on standardized extraoral and intraoral photographs (see Photo Documentation Protocol, Appendix 1), the pretreatment diagnostics are performed.
1.4.3 Time points for diagnostics, diagnostic tools
Three time points exist for the assessment of the diagnostic goal.
The first and ideal time point is before any invasive treatment is performed. A medical and dental anamnesis including a detailed esthetic anamnesis is performed to understand the patient’s needs5, followed by a comprehensive extra- and intraoral examination. The restorative team gathers all the information to evaluate the clinical situation, and elaborates the need for treatment. Considering the complex and subjective nature of esthetics, an objective means for the evaluation of the tentative outcome is helpful for the decision-making process1,3. The diagnostic wax-up serves as an objective tool for the evaluation of potential treatment outcomes3,6,7. It improves the communication between patient, technician, and clinician, illustrating three-dimensionally the tentative treatment outcome1,3,8. Commonly, the dental technician models a possible dental configuration in wax using clinical pictures and anatomical landmarks on the diagnostic cast (existing occlusal plane and length and position of the remaining teeth) as references. This process requires an undeniable amount of time and energy since the technician must integrate all the esthetic guidelines and adapt them to each individual case. The wax-up is later tried-in in the patient’s mouth to evaluate its integration into the patient’s smile and face, on what is called a diagnostic try-in. A silicone matrix made from the diagnostic wax-up serves as a negative cast for the fabrication of the diagnostic mock-up, which will be filled with autopolymerizing resin and placed over the unaltered natural teeth until polymerization. This mock-up allows the patient and restorative team to envisage and evaluate the possible restorative outcome1. This procedure, however, is only feasible in certain clinical situations and it will only be effective in situations where additive restorations are foreseen as the mock-up lies over the unprepared teeth. In cases where subtractive procedures are necessary the intraoral transfer of the wax-up will need to be performed at a later treatment stage after the preparation.
The second time point to evaluate the esthetic and functional outcome of the prospective restoration is the provisional phase. Indirect provisional restorations made in the laboratory according to the diagnostics serve as transfer of the desired treatment outcome into the clinical situation and are useful tools to evaluate the diagnostic goal (see also Part I, Chapter 8).
In the present treatment concept, conventional or digital eggshell provisional restorations are the first option. For the conventional eggshell provisionals, the technician duplicates the shapes modeled in wax into a tooth-colored resin, which then is hollowed on the internal side until only a thin outer resin layer remains. Alternatively, the eggshell provisional can be milled out of a resin ingot by means of a computer-assisted design and computer-assisted manufacturing (CAD/CAM) procedure following a virtual wax-up. These eggshell provisional restorations allow the clinician to deliver a high-end laboratory provisional during the first invasive appointment. The tentative final restoration contour is relined intraorally with autopolymerizing resin on the prepared abutments. This method saves time and costs derived from a traditional indirect provisional fabrication (impression on prepared abutments, bite registration, chair-side direct provisional production, and a second appointment to deliver the laboratory provisional), while allowing for a perfect fit of the provisional crown margins. Patients suffering from insufficient restorations or unsatisfactory dental appearances gain significantly from this direct approach, since the esthetic improvement can be perceived immediately after the initial preparation and the insertion of the provisional.
The third and last time point to determine the desired restoration design is after the final impression is performed and before the framework is produced. The patient’s and restorative team’s impression derived from the previous two diagnostic steps (diagnostic mock-up and provisional phase) are thereby taken into consideration, and a new tentative configuration is confectioned over the prepared abutments on the final cast. Using tooth-colored wax, the technician produces a wax try-in that will simulate the color and contour of the final restoration. When the case involves edentulous spans or multiple units, the wax structure can require a metal or resin framework to improve its strength. An advantage of this diagnostic maneuver lies in the plasticity of the wax, which allows for immediate modifications of possible imperfections discussed during the try-in appointment. Once the patient and the restorative team have agreed on the optimal restorative outline, the wax try-in will be used as a reference to determine the shape and thickness of framework and veneering of the final restoration.
As previously mentioned, high efforts are devoted to identify and mimic the desired esthetic outcome before the technician begins the final restoration production. Despite the significant amount of energy and time invested to come up with a diagnostic draft, the obtained result may not match the patient’s physiognomy or personality, or it may not represent the desired result the restorative team and the patient expected. In these cases, small changes to modify this initial draft can be attempted. However, the range of modifications is limited and often a new