Laypersons’ esthetic perception of various computer-generated diastemas: A pilot study Ali Noureddine, DDS,a,b Hélène Fron Chabouis, DDS, MSc,c,d Sarah Parenton, DDS,a and Jean-François Lasserre, DDS, PhDd Faculty of Dentistry, Bordeaux Segalen University, Bordeaux, France; Faculty of Dentistry, Paris Descartes University, Paris, France; Paris North 13 University, Paris, France; Charles Foix Hospital, Ivry-sur-Seine, France Statement of problem. Managing excess anterior spacing is a common problem in dental practice. During orthodontic or restorative treatment planning, clinicians must decide how to distribute this space. However, few reports are available in the dental literature about the attractiveness and esthetic impact of anterior spaces other than midline diastemas. Purpose. The purpose of this study was to compare the esthetic perception of 4 different anterior diastemas, including simian diastemas (symmetrical diastemas between lateral incisor and canine), diastemas suggested by Frush and Fisher (asymmetrical diastemas between lateral incisor and canine and between central and lateral incisor), and by Lombardi (slight midline diastema and 2 larger diastemas between central and lateral incisors), and a midline diastema. Material and methods. A picture of a young woman’s smiling face was modified by using photoediting software to create the 4 previously mentioned diastemas. The resulting pictures were presented to laypersons questioned in French public places. The participants were asked to rank the pictures from most to least attractive, then to rate them with a mark from 1 to 10. Results. One hundred and five participants completed the questionnaire. The median ranks and scores attributed to the pictures from most to least attractive were as follows: simian diastemas, 1 and 8; Frush and Fisher diastemas, 2 and 7; Lombardi diastemas, 3 and 5; and midline diastemas, 4 and 4, respectively. The hierarchy (simian diastemas>Frush and Fisher diastemas>Lombardi diastemas>midline diastemas) could be established statistically for the scores (P¼.03, P FD> LD> reference ¼ MD). The same hierarchy could be observed from the unadjusted regression of the ranks, but this conclusion could not be drawn when the ranks were adjusted for the sex and age of the participants (Table IV).

DISCUSSION

w 1

y 1

m 1

o 1

w 2

m 2

w 3

m 3

MD

LD

FD

SD

y 2

o 2

y 3

o 3

MD

LD

FD

SD

w 4

m 4

B

y 4

o 4

C

6 Proportion of ranks (1, 2, 3, 4) attributed to each diastema. A, Overall rank distribution. B, Rank distribution by men (m) vs women (w). C, Rank distribution by young (y) vs older people (o). regression retrieved the average scores for each diastema (Table V) and allowed testing for scores equality (Table VI). Adjusting for the age and sex of the participants slightly modified the regression coefficients compared to those obtained in univariate analysis: older people gave better scores

Noureddine et al

(P¼.013), and women slightly better scores (not significant). The ranking reconstructed from the scores was fairly well correlated with the ranking set forth by the participants. It was exactly the same for 62 participants (59%) and identical to the reconstructed ranking for 97

This study involved modifying an image of a woman’s smile with photoediting software to obtain various types of diastemas and then comparing them. For this portrait and smile, this survey revealed a hierarchy in the esthetic perception of the laypersons who participated, thus rejecting the tested null hypothesis. Simian diastemas were rated as more attractive than the asymmetrical diastemas suggested by Frush and Fisher,13 which were rated as more attractive than the symmetrical diastemas suggested by Lombardi.14 The smile with the midline diastema was rated as the least attractive. More specifically, the scores of simian and Frush and Fisher diastemas were the highest with relatively close marks, while the scores attributed to the Lombardi diastemas and to the midline diastema were significantly lower. Thus, in the case of bilateral diastemas, midline symmetry does not seem to greatly affect smile attractiveness, since the ratings for simian diastemas and Frush and Fisher diastemas were rather close (median 8 and 7). In contrast to these 2 diastema distributions, the 2 least attractive diastemas had in common the presence of a midline gap. Furthermore, the simple midline diastema was judged less attractive than the Lombardi distributed diastemas, although the latter presented greater overall spacing, with a narrower midline gap. Therefore, the midline diastema may be the gap that most negatively affects smile

6

Volume Coefficients (95% CI) obtained through unadjusted or adjusted (for age and sex) probit regression for diastemas’ ranks

Table III.

Diastema

Unadjusted Coefficient (95% CI)

Adjusted Coefficient (95% CI)

SD

1.76 (1.35-2.18)

1.72 (0.80-2.64)

FD

1.49 (1.11-1.88)

1.41 (0.48-2.33)

LD

0.87 (0.52-1.21)

0.78 (0.03 to 1.60)

MD

e

e

CI, confidence interval; SD, simian diastema; FD, Frush and Fisher diastema; LD, Lombardi diastema; MD, midline diastema.

P values for testing a hierarchy in diastemas’ ranks after probit

Table IV. regression

Adjustment of Regression on Demographic Characteristics

Was SD>FD?

Was FD>LD?

Was LD>MD?

Unadjusted

.002

LD?

LD>MD?

.032