Table 1.

Summary of the main treatment parameters for MLIA patients.

Parameter	Space closure and tooth recontouring	Implant supported restorations
Patient age	Space closure may be performed in younger MLIA patients, with the use of conservative restorative approaches (resin buildups or ultra-thin porcelain veneers).	Implant placement should only be performed after the completion of facial growth (18-19 years for women and 20-21 years for men).
Long-term follow-up	- Natural dentition is maintained; - Alveolar bone height maintained; - Anterior teeth may reopen after space closure, however, this may be avoided with a long-term fixed lingual retainer.	- Implants cannot change position. Over time, with the normal changes in occlusion and alveolar bone patterns, implant crown might become more infraoccluded and protrusive.
Occlusion	Group disclusion pattern.	Possibility of ideal intercuspidation with canine-protected occlusion.
Periodontal parameters	Patients do not present periodontal complications due to the maintenance of the natural dentition	Higher prevalence of gingival inflammation, increased probing depths and lack of dental papilla
Gingival architecture	- Gingival zenith after space closure may not accomplish the ideal esthetic parameters when the orthodontic treatment is not adequately performed.	- Implants may provide ideal papilla filling and gingival zenith. However, these may change over time. - The progressive loss of marginal bone may result in gingival discoloration and exposure of implant abutment, which may compromise esthetics.
Tooth proportion	- Canine recontouring results in lateral incisors with altered width-height ratio in comparison with natural lateral incisors.	- The width of the agenesis area can be orthodontically adjusted. However, patients may present implant supported crowns higher than natural lateral incisors. The height of implants will be determined by the level of the crestal bone and keratinized gingiva