Influence of gingival display on smile aesthetics in Japanese

Abstract

The aim of this study was to evaluate the influence of the amount of gingival display on smile aesthetics as assessed by Japanese orthodontists and dental students. A coloured photograph of a smiling female, displaying the first molar to first molar, whose upper lip was tangent to the upper gingival margin of the upper central incisors (zero point), was constructed from different subjects. Gingival displays were modified by moving the teeth within the lip frame in 1 mm increments, from -5 to 5. Using a visual analogue scale (VAS), 31 Japanese orthodontists and 55 Japanese dental students rated the attractiveness of the 11 smiles with altered gingival display. There was no significant difference when judging the effects of the gingival display on the smile attractiveness between the male and the female raters for both the orthodontists and dental students. Kruskal-Wallis tests revealed significant differences in the median aesthetic scores for both the orthodontists and dental students. For the orthodontists, the median aesthetic score increased gradually from -5 to 0 mm and then decreased from 0 to 5 mm. In particular, it decreased to become clinically significant (15 per cent VAS difference) from 0 to 3 mm. For the dental students, the median aesthetic score increased gradually from -5 to -2 mm and then decreased from -2 to 5 mm. The dental students were less tolerant of a more 'gummy' smile than the orthodontists.

Aesthetic perception of gingival smiles

“…This agrees with results of the studies by Ioi et al 9 6 , who claim that laywomen are less critical of smiles with greater gingival display than men, and with Cracel-Nogueira, Pinho 4 , who say that laywomen and dentists are more critical with respect to the degree of gingival display.…”

“…Currently, many studies have shown that the characteristics of an aesthetic smile, according to dental professionals and laypersons, are different. Some of these studies have worked with computer modified photographs and are shown to be an effective method for evaluating the different perceptions 3,4,6,[9][10][11][12]14 . Analyzing the aesthetic perception of patients and professionals in relation to increased gingival display (gingival smile), it was observed that, according to general practitioner dentists and periodontists, 1.5 mm of gingival display compromises the aesthetics of the smile.…”

“…It was digitally modified on the gingival margin of the upper anterior teeth, by a professional photographer using the Adobe Photoshop software (Adobe Systems Inc., San Jose, California), to create a gingival smile, using a similar method to that adopted in other work 3,4,6,[9][10][11][12][13][14][15] . The photograph was modified every 0.5 mm up to a level of 2.5 mm, totaling six photos, as shown in Figure 1.…”

“…Each volunteer received the photo album of smiles, and evaluation sheets containing a visual analogue scale (VAS) of 100 mm of which the leftmost position indicated "not attractive smile" and the rightmost position indicated "very attractive smile", as used in other studies 3,4,9 . They had a maximum of 20 minutes to complete the evaluation sheets in the presence of at least one researcher.…”

Dimensional analyses of frontal posed smile attractiveness in Japanese female patients

“…17 These differing results suggest that it is important to consider the ethnic and cultural background of both patients and evaluators when analyzing the smiles of orthodontic patients. Ioi et al 29 pointed out that there is insufficient evidence to support what is considered an attractive smile in the Japanese population. Therefore, the present study is the first to report about Height-1 and Height-4 among the 14 gingival display, 13 and maxillary gingival display, 18 was 0.53 6 0.90 mm in the nonmanipulated images of young female patients in group A.…”