Introduction

Diagnosis and treatment planning is indispensable for treatment success. Detailed plans are always prepared and approved before any beautiful building is ever constructed (Figure 8.1a,b). Similarly, knowing the final restoration outline based on known dentofacial principles, the patient’s esthetic goals and the occlusal requirements leads to predictable results, patient satisfaction and minimally invasive preparation, as described in Chapter 7. Smile design is not just a luxury; it is indispensable, and combined with occlusal analysis is an integral part of a thorough diagnosis. As clinicians, it can be easy to focus on the principles we know and overlook a patient’s goals when they come in for esthetic improvement. Diagnosing on only retracted photographic views or a cast of the patient’s teeth can lead to focusing on the tooth shape and gingival condition, while the overall appearance of how the smile should enhance the entire face can be lost. Similarly, sending a set of casts to a laboratory, and asking for wax-ups without detailed instructions is basically a Las Vegas style gamble.

The Psychology of the Smile

When patients come in for esthetic dental treatment, they are looking at the “big picture” – they want to look better, not just the teeth but the smile and thus the entire face, and so should clinicians, or unhappy patients will be the results (Figure 8.2a,b) [1]. Understanding the importance that the smile has in human social interaction and overall emotional wellbeing should increase awareness of the great importance that smile design has when treating the anterior dentition (Figure 8.3) [2,3]. Dentofacial esthetics is the evaluation of teeth as they relate to other facial structures and facial symmetry that is influenced by the teeth. As with anything related to esthetics, it is subjective, but has some basic rules [4,5,6].

Any time that multiple anterior teeth are being planned for treatment, a dentofacial evaluation and design should be the first step to ensure a harmonious dentofacial outcome. The evaluation and design should also take into consideration the entire occlusal scheme, which will lend to stability and longevity of the dentition (see Chapter 13). This process mirrors that of building construction or extensive remodeling. It always begins with an architectural design with the goal of beauty, and then ensuring proper engineering and function. X-rays and periodontal charting, caries assessment and periodontal therapy should be integrated with the overall diagnosis.

Parameters, Not Rules

Predictable results and patient satisfaction can be easily obtained by systematically recording the patient’s goals and preferences and blending them with known esthetic parameters. Through a series of forms and two-way communication, the dentofacial esthetic diagnosis system takes a clinician step by step, guiding with principles, but not giving absolute rules, so as to allow for individual preference.

Some important parameters apply in this process. Again, the subjective nature of beauty requires latitude for choices and opinions (Figure 8.4a,b). There are, on the other hand, clinical parameters for ensuring a healthy occlusion, as well as esthetic parameters that are universal in the definition of beauty [7,8].

Record Gathering

Before the smile diagnosis can be completed with the patient, information must be gathered that can be used for diagnosis and presented to the patient. This information can also be used to communicate with members of the esthetic team, such as the restorative dentist (working as team leader), any specialists involved (orthodontist, periodontist, oral surgeon) and the laboratory technician. Photographs allow for the assessment of tooth position in relation to face and lips. Photography is an excellent way to show patients multiple views of their face, smile and teeth, in order to come to a mutual agreement on treatment. The following records can and should be completed by a well-trained dental assistant (local laws may limit auxiliaries’ duties): A full set of periapical x-rays, panoramic x-ray (not required but highly recommended), six-point periodontal charting, and articulated casts mounted using a face bow and a semi-adjustable articulator. Finally, a high-quality 11-photograph series, which can be acquired with a simple point-and-shoot digital camera (Box 8.1).

Smile Design Step By Step

The 11 simple photographs (Box 8.1) [9] taken by the assistant are displayed on the computer screen or printed, allowing the patient to observe their own smile from different views. All findings are recorded on the dentofacial esthetic diagnosis form (Figure 8.6) [10]. The 25 parameters of dentofacial esthetics are best illustrated photographically, and it is a simple way to organize them. Each view and parameters therein will be assessed, and only those parameters with problems will be discussed by the clinician with the patient:

• Is the parameter within acceptable limits? If so, it is not necessary to discuss this with the patient.
• Can the problem be corrected with restorative dentistry? If yes, explain specific treatment to the patient, including options, and estimated cost to correct. If not correctable, explain limitations; or
• Suggest specialist referral option (orthodontist, periodontist, oral surgeon).

It is important to bear in mind that only a few parameters will need to be discussed. Usually only five or six problematic parameters will be addressed, and the entire smile design procedure should take approximately 10–15 minutes in most cases.

The 25 Parameters

The following are general guidelines for each of the 25 dentofacial parameters and should not be considered as rules. Each parameter discussed will be tempered by the patient’s own preferences, their willingness to proceed with any corrective treatment, balanced by the patient’s budget. Using the dentofacial esthetic diagnosis form easily walks the clinician through the esthetic and clinical parameters, while allowing notes to be taken for review and diagnosis later on (Figure 8.7).

1 Occlusal Plane, Front Full-Face Smiling (Figure 8.8) [11]

Take an imaginary line parallel to the horizon and touching the incisal edges of both centrals, and either the incisal edge of the canines or equidistant to both canines, laterals and the rest of the dentition. (Figures 8.9, 8.10a–c). The use of a facebow-mounted cast can greatly help in evaluation and laboratory communication and correction (Figure 8.11a,b).

2 Midline (Front Full-Face Smiling) [12]

This is a vertical line which dissects the face vertically and can use glabella (the point where the nose and forehead connect) and filtrum or cupid’s bow, as a facial reference. Ideally, the facial midline and the dental midline should coincide, but often they do not. As long as the midline is perpendicular to the occlusal plane, the dental midline can be up to 2 mm off-center and the human eye can barely detect the disparity (Figures 8.12a–c, 8.13a,b). The use of a facebow-mounted cast can greatly help in the evaluation, in communication with the laboratory and in correction (Figure 8.14a,b).

3 Facial Symmetry (Front Full-Face Smiling)

Any obvious facial asymmetry should be noted, as it can throw off the occlusal plane and midline. Facial asymmetries can greatly complicate the evaluation and communication with the laboratory, and may lead to compromised results. Only by the correct use of a calibrated facebow-mounted cast will good communication with the laboratory and acceptable corrections be possible (Figure 8.15a–d).

4 Lip Position (Profile)

It is important to consider the lip position and lip support when large changes in dental protrusion are being consider with orthodontics or restorative dentistry (Figure 8.16), as the lips are supported by the teeth [13], and changes will have a positive or negative effect on the look of the lips. Ricketts E-line [14] is an imaginary line drawn between the tip of nose and tip of chin, where the upper lip should be 1 mm from the line and the lower lip should touch it (Figure 8.17). This parameter is, however, subjective and dependent on ethnicity, and for these reasons the patient’s opinion should be the primary guideline (Figure 8.18a–e).

5 Facial Lower Third (Profile view)

A collapsed lower third has an aging effect. The lower facial third collapses primarily due to a lack of posterior teeth to support the vertical dimension of occlusion and severe occlusal wear. This parameter should be considered when orthodontic or extensive restorative treatment is being planned, as improvements can be very rejuvenating (Figure 8.19) [15,16,17,18].