Australasian Dentist Magazine May June 2021

Category 50 Australasian Dentist The dreaded black triangle – significance of natural crown shape P apillary recession is a potential aesthetic complication following the extraction of an anterior tooth and its replacement with an implant-borne crown. The resultant form is an interdental space notoriously known as, “the black triangle”. Factors that can influence the presence or absence of papilla include availability of underlying osseous support, periodontal biotype (thin or thick), periodontal bioforms (high, normal or flat), contact point position and tooth morphology (square, square tapered, or triangular). In my practice, prior to obtaining consent from a patient requiring replacement of a maxillary central incisor with an implant-borne crown, the potential indication and cost (financial and biological) for restoration of adjacent teeth is routinely discussed. Patients are informed that the shape of the natural tooth may be a predictor of the need for an adjacent restoration and that triangular teeth, in particular, are more predisposed to black triangle outcomes. During planning, my patients are advised about the potential need to change the original shape of an adjacent tooth in order to close black triangles, diastema or to achieve symmetry. Here’s a nice article which I’ve found useful in applying some principles in my patient care. In a study by Gobbato et al 1 , 60 patients, each with a maxillary central incisor implant-borne crown, and whose aesthetic result had gingival and dental symmetry, clinical By Dr Alan Yap, prosthodontist no “black triangles”, and no diastema – it was discovered that most (65%) of the teeth that were triangular in shape received an additional restoration on the adjacent central incisor. Some (40%) of the square-tapered group required an additional restoration, and few (13.3%) of the square group required an additional restoration. All teeth requiring additional restorations had their original shape changed to a square form. Additional restorations included composite resin restorations, porcelain veneers and crowns. u Reference (1) Gobbato L, Paniz G, Mazzocco F, Chierico A, Tsukiyama T, Levi P, Weisgold A. Significance of crown shape in the replacement of a single central incisor with a single implant-supported crown Quintessence Int 2013;44:407–413.