Abstract
BackgroundA number of reference patterns such as the interincisal line, curve of the upper lip, width of the smile or shape of the teeth have been studied in different populations. Determining the frequency of different smile aesthetic parameters in a European Caucasian population and exploring possible gender differences is important in order to obtain predictable treatment outcomes.MethodsPhotographs were obtained under resting and forced smiling conditions in 140 individuals (70 males and 70 females) with a mean age of 20.1 ± 4.3 years. Different variables were recorded, including the position of the maxillary interincisal midline in relation to the facial midline, the arc and width of the smile, and the shape of the teeth. The data were processed using the SPSS version 15.0 statistical package, with application of the chi-squared test and a confidence level of 95%. The statistical power was 80%, and the level of significance 5% (α = 0.05).ResultsA total of 94.3% of the sample presented a maxillary interincisal midline coinciding with the facial midline, and 80% had a consonant smile line. The curve of the upper lip was upwards in 47.1% of the cases, followed by a straight curve in 41.4%. Most of the subjects (84.3%) presented a medium smile line with tooth exposure to the second premolar (61.4%). There were no significant differences between males and females.ConclusionsThe integration of aesthetic criteria is needed in order to guarantee satisfactory and predictable dental treatment outcomes. There were no statistically significant differences between males and females. The maxillary interincisal midline coincided with the facial midline, with a consonant smile arc and a medium smile line, upward lip curve and oval tooth shape.
Highlights
A number of reference patterns such as the interincisal line, curve of the upper lip, width of the smile or shape of the teeth have been studied in different populations
Maxillary interincisal midline versus facial midline In the great majority of the subjects (94.3%; n = 132), the maxillary dental midline coincided with the facial midline, while 5.7% (n = 8) showed deviation (Fig. 1) (Table 2)
With regard to smile width, our results indicate a greater prevalence of exposure to the second premolar (61.4%), in agreement with the observations of other authors [29, 31]
Summary
A number of reference patterns such as the interincisal line, curve of the upper lip, width of the smile or shape of the teeth have been studied in different populations. There are two types of smile: spontaneous and forced The former is involuntary, with elevation of the lip induced by happiness, and can be taken to express genuine emotion [11]. In facial analysis we have a number of horizontal reference lines (the bipupillary line and other lines parallel to the latter) and the vertical midline located by two anatomical reference points: the nasion and the filtrum [6]. The more perpendicular this line is to the
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