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Considerations for the incisal edge and smile line, considerations for multiple tooth replacement including dentures, veneers, and all-on-4 restorations

Below is a list of things that may play a role in determining what you can and can’t do when it comes to incisal edge placement for a variety of restorative procedures, including crowns and veneers.

 

  • 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.