Comparison between incisal embrasures of natural and prosthetically restored maxillary anterior teeth

The loss of one or more of the incisal embrasures may pose a problem in restoring missing tooth structure. Despite its acknowledged importance in dental esthetics, few researchers have investigated the esthetic impact of incisal embrasures.

The purpose of this study was to compare parameters of the incisal embrasures of natural maxillary anterior teeth (ND) with those of prosthetically restored maxillary anterior teeth (PRD) and to compare the resemblance of the prosthetic restoration to natural form.

Twenty gypsum casts of the maxillary anterior teeth (MAT) of patients made at the completion of their orthodontic treatment comprised the control group. The experimental group consisted of 20 gypsum casts of prosthetically restored maxillary anterior segments. Five incisal embrasures of each cast were digitally photographed under uniform, standardized conditions: the incisal embrasures between the canine and lateral incisor on each side, between the lateral and central incisors on each side, and between the 2 central incisors. The photographs were measured by image analyzing software (Bioquant Nova Prime). The parameters compared were: (1) the areas of the incisal embrasures in the natural and prosthetic casts (measured in mm(2)); (2) the areas of homological incisal embrasures in each of the groups; and (3) the degree of lateral symmetry of the natural casts as compared to the prosthetic casts. The results were subjected to 2-way ANOVA and Student t tests (alpha =.05).

The total area of incisal embrasures of the PRD casts was smaller than the total area of those of the natural dentition casts (P=.005). The incisal embrasures of the PRD casts were smaller than the homological embrasures of the natural dentition casts (P<.01). Both groups demonstrated a lack of lateral symmetry (P<.001). The natural dentition casts demonstrated a greater asymmetry than the restored dentition casts (canine/lateral P<.045 and lateral/central P<.035). There was no significant difference in the sizes of the central incisal embrasures of the 2 groups. The corresponding incisal embrasure areas (ND versus PRD) were significantly different, except for the 2 central embrasures.

Prosthetically restored dentition casts differed from natural dentition casts in 2 parameters: the area of the incisal embrasures and the degree of lateral symmetry.