Anterior aesthetics Part 1: Smile design

So I was waxing up a case last week and realised that I had completely forgotten what front teeth looked like. So I caught up on some anterior aesthetic lectures and wrote down the tips and rules to follow when designing anterior teeth. As long as you stay within these rules, your restorations end up looking more natural and aesthetic. There is room for creativity within the rules but the rules themselves are quite important to stick to:

-When designing your smile digitally you want to move from macro details to micro. Start with aligning your full face smile photograph making sure the teeth will be designed straight.
-Look at lip at rest photographs to see the incisal display. Older patients will tend to show less upper teeth and more lower teeth. Lower teeth tend to be more visible during speech and upper teeth tend to be more visible during smiling. This photograph will start to give you an idea where you want your incisal edges to finish. Use your judgement in the context of the patient's age and aesthetic expectations
-A full smile photograph will show you the mobility of the lip from rest. The hypermobility of some lips will surprise you. There is no point lengthening incisors to have display at rest if they end up looking too long at full smile. Use this photo to judge the extent of gingival display and the symmetry of the gingiva. Excessive gingival display may require lengthening of the teeth with gingivectomy/crown lengthening, orthodontics, or may be a maxillofacial issue. Gingival symmetry may necessitate soft tissue work to even both sides. Sometimes a compromise must be struck in terms of symmetry when the patient has a severe cant or an asymmetric smile. The planned midline can be determined on this photo by observing the midpoint of the pupils or using the line of the nose or a line drawn from the middle of the philtrum or a combination of the above.
-All frontal photos should be aligned with the horizontal plane of the face (interpupillary line)
-A close up smile photograph is used to start designing the desired length of the anterior teeth. Aim for the incisal edges of the anterior teeth to follow the contour of the lower lip and generally be within 3mm of the superior border of the lower lip. This is only a guideline and can't be relied on as it is not a stable reference point. It may be more prudent to have 0mm to 2mm of upper incisal display at rest in a young patient and 1mm to -2mm display in an older patient. This may need to be altered if there is a poorly or hypermobile lip during smile. Once you have an idea of the length and curvature of the incisal edges you can draw a smile curve in the shape of a horizontal "0" which can be transferred to the retracted  intraoral photo.
-Retracted intraoral photos must be aligned with the horizontal plane of the face (interpupillary line). It is where you will design the shape of the upper and lower teeth. This is where you need to follow the rules for anterior tooth shapes (future posts).
-Be sure to standardise your photos. Take the same photos for every case as a baseline and add on any extras as you see fit. Have the patient standing against a blank background for the non mirror shots and make sure you are on the same vertical plane for every photograph to avoid parallax error.