Considerations for the incisal edge and smile line, considerations for multiple tooth replacement including dentures, veneers, and all-on-4 restorations
A few considerations…
- High lip line is higher with a spontaneous smile (vs posed) smile. More of premolars show too (30%) with natural smile.
- Options for moving incisal edges: Crown lengthen and shorten tooth vs intruding teeth with orthodontic care.
- Things to evaluate when looking at incisal edge: Tooth display at rest, lip mobility, occlusal plane, and facial/lingual position.
- You want incisors to show when talking or at rest (otherwise it looks like you have no teeth).
- You don’t want the incisal edge above the buccal cusp of premolars or you will get a reverse smile line. To evaluate, have person touch lips, then relax lips without smiling.
- As you age, you show less maxillary incisors (from soft tissues dropping on the skeletal base).
- Over-eruption (from a class 2) can cause more teeth to show at rest than expected.
- Tooth wear can cause less tooth to show at rest.
- You have to take into account where the incisal edge is both AT REST and with full NATURAL SMILE.
- Normal amount of lip mobility is 6-8mm. This is often determined by the alveolar ridge. As the teeth and alveolar ridge moves forward it leads to more mobility… retruded leads to less mobility.
- Hyper-mobile lip is a problem and often cannot be treated “tooth-wise.” If the incisal edge is in the right place at rest with normal size teeth but then they show 7+mm gingival, it may be wise to consider Botox or lip repositioning surgery.
- There are several things that limit lengthening of incisal edges: Overall tooth display, phonetics, and occlusion to name a few.