title: Significance of crown shape in the replacement of a central incisor with a single implant-supported crown.
abstract: OBJECTIVE
  When utilizing a single implant-supported crown to replace a central incisor, understanding the final shape of the implant restoration is an important factor to help achieve a successful esthetic outcome. In today's dentistry, tooth shape is a critical factor when dental implant prostheses are considered in the esthetic zone. The major esthetic goal for this type of restoration is to achieve the closest possible symmetry with the adjacent tooth, both at the soft and at the hard tissue levels. The goal of this study was to objectively analyze the significance of natural crown shape when replacing a central incisor with a single implant-supported crown.
  
  
  METHODS
  In this study, we investigated the shape of the crowns of maxillary central incisors in 60 individuals who presented to our clinics with an untreatable central incisor. The presence of a dental diastema, "black triangle," presence or absence of gingival symmetry, and the presence or absence of dental symmetry were recorded in the pre- and postoperative photographs.
  
  
  RESULTS
  Out of 60 patients, 33.3% had triangular-shaped crowns, 16.6% square/tapered, and 50% square-shaped crown form. After treatment was rendered, 65% of the triangular group, 40% of the square/tapered group, and 13.3% of the square group required an additional restoration on the adjacent central incisor in order to fulfill the esthetic needs of the patients.
  
  
  CONCLUSIONS
  Data analysis revealed that if there is a "black triangle," a diastema, or presence of dental or gingival asymmetry, an additional restoration on the adjacent central incisor is often required in order to fulfill esthetic goals. The additional restoration is highly recommended in situations with a triangular crown shape, while it is suggested in cases of square/tapered and square tooth shapes in the presence of a dental diastema.
authors.affiliation: Department of Oral Medicine, Harvard School of Dental Medicine, Boston, MA 02115, USA. Gobbato@hsdm.harvard.edu
authors.forename: Luca
authors.initials: L
authors.lastname: Gobbato
authors.forename: Gianluca
authors.initials: G
authors.lastname: Paniz
authors.forename: Fabio
authors.initials: F
authors.lastname: Mazzocco
authors.forename: Andrea
authors.initials: A
authors.lastname: Chierico
authors.forename: Teppei
authors.initials: T
authors.lastname: Tsukiyama
authors.forename: Paul A
authors.initials: PA
authors.lastname: Levi
authors.forename: Arnold S
authors.initials: AS
authors.lastname: Weisgold
mesh_terms: D003442:Crowns; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003793:Dental Restoration, Permanent; D003801:Dental Veneers; D003970:Diastema / Q000628:therapy; D004955:Esthetics, Dental; D005881:Gingiva / Q000033:anatomy & histology; D006801:Humans; D007180:Incisor; D008437:Maxilla; D012189:Retrospective Studies; D019228:Tooth Crown / Q000033:anatomy & histology*