Investigation of the esthetic perception of different canine parameters

Abstract

Objectives: The aim of this study is to analyze the esthetic perception of selected canine features, namely crown length, shade, inclination, and angle of incisal edge tip.

Materials and methods: The anterior maxillary teeth of a Central European woman were photographed and digitally modified in order to investigate esthetic perceptions of the above four categories. Three groups of examiners with different levels of experience in the field of dentistry (laypersons/inexperienced dental students, advanced dental students, dentists) evaluated the photographs twice with the help of visual analogue scales.

Results: The best-evaluated canines have approximately the same length as the central incisor, have the same shade as the other anterior teeth, are best embedded in a lighter overall tooth shade, are neutral to slightly palatal inclined, and have a right angled to rounded incisal edge (≥ 90°). The canines evaluated as least esthetic, however, are longer than the central incisors, darker, inclined labially, and have a tapered incisal edge. No significant differences could be found between the evaluations of the groups with regard to the four feature categories.

Conclusions: Laypersons, advanced dental students, and dentists generally evaluate according to the same esthetic standards. Gender does not have a significant influence on evaluation. Clear definitions of esthetically favored shades, incisal edge shapes, inclination, and lengths of the canines can be given.

Clinical relevance: Since the esthetics of the smile line play a critical role for patients, dentists, dental technicians, and their supplying industry, knowledge of the esthetically preferred morphology of canines is essential.

Clinical significance: The aim of this study is to give clear definitions of esthetically favored shades, incisal edge shapes, and lengths of the canines, as the esthetics of the smile line play a critical role for patients, dentists, dental technicians, and their supplying industry (e.g., denture tooth manufacturers). Precise knowledge of esthetic preferences is important in clinical practice for both dentists and dental technicians, for example, in order to adequately advise patients regarding esthetic corrections. Also, in the case of missing teeth, this knowledge is essential for optimal and satisfactory restorations. Thus, this study can contribute to the satisfaction of general practitioners and patients.

Keywords: Angle of incisal edge tip; Canine inclination; Canine morphology; Crown length; Esthetics; Tooth shade.

Fig.1

Example of a photograph used in this study (“uniform tooth shade”)

Fig. 2

Image set for “crown length of canines”: a 1:1.02 cent. inc., b 1:1 cent. inc., c 1:0.95 cent. inc., d 1:1.05 lat. inc., e 1:1 lat. inc

Fig. 3

Image set for the category “tooth shade”: a darkened anterior teeth + adapted canine, b darkened anterior teeth, c uniform tooth shade, d brightened anterior teeth, e brightened anterior teeth + adapted canine

Fig. 4

Image set for the category “inclination of canines” (in degrees): a − 10, b − 5, c 0, d + 5, e + 10

Fig. 5

Image set for the category “angle of the incisal edge tip” (in degrees): a 100, b 95, c 90, d 85, e 80

Fig. 6

Ratings for the category “crown length of canines” using the visual analogue scale (y-axis: 0 corresponds to least, 100 to most esthetic). The x-axis indicates the gradations of the feature category, in this case the relative length (in each case with reference to the central [“cent. inc.”] or lateral [“lat. inc.”] incisor) in ascending order. Multiple comparison resulted in the subgroups from s1 to s4 with p ≤ 0.05 across subgroups, indicated by *

Fig. 7

Ratings for the category “crown length of canines”. The ratings show significant differences between length ratios but similar rankings for all groups

Fig. 8

Ratings for the category “tooth shade”. Multiple comparison resulted in three subgroups with p ≤ 0.05 across subgroups: The first subgroup is formed by “darkened anterior teeth”, “darkened anterior teeth + adapted canine” and “brightened anterior teeth” (s1). In addition, the last two one form a subgroup with “uniform tooth shade” and “brightened anterior teeth + adapted canine” (s2). These two also form a third subgroup (s3)

Fig.9

Ratings for the category “inclination of canines”. Multiple comparison resulted in two subgroups: Only + 10° showed significant differences to the other inclinations

Fig. 10

Ratings for the category “angle of the incisal edge tip”. Angles from 90° to 100° form a subgroup; 80° and 85° were rated significantly worse