Indian Journal of Dental Research

ORIGINAL RESEARCH
Year
: 2008  |  Volume : 19  |  Issue : 3  |  Page : 204--207

The effects of upper lip height on smile esthetics perception in normal occlusion and nonextraction, orthodontically treated females


Arezoo Jahanbin, Hossein Pezeshkirad 
 Department of Orthodontics, Mashhad University of Medical Sciences, Iran

Correspondence Address:
Arezoo Jahanbin
Department of Orthodontics, Mashhad University of Medical Sciences
Iran

Abstract

Background: The esthetic of smile is influenced by such features as the amount of incisor show and gingival display. Aims: The purposes of this study were to compare smile esthetics among normal occlusion and non extraction patients, assess upper lip height in two groups and discuss how this feature relate to smile esthetics. Settings and Design: We therefore conducted a case control study to determine the mentioned aims. Materials and Methods: Thirty females with non extraction orthodontically treated occlusions and thirty three with normal occlusions were selected. Standardized black and white photographs of their posed smiles were evaluated by a panel of 5 men and 5 women of varied vocations by use of visual analogue scale. Then upper lip height of the two groups were measured from photographs. Statistical Analysis: Smile esthetics and differences among the two groups were subjected to ANOVA and Mann-whitney test was used to compare upper lip height in them. Results: This study showed that upper lip height did not differ among the 2 groups ( P = 0.98). Also there were no significant differences in the distribution of fair,good and very good smiles among the two groups. Conclusions: This study demonstrates that the non extraction orthodontic treatment does not influence smile esthetics.



How to cite this article:
Jahanbin A, Pezeshkirad H. The effects of upper lip height on smile esthetics perception in normal occlusion and nonextraction, orthodontically treated females.Indian J Dent Res 2008;19:204-207


How to cite this URL:
Jahanbin A, Pezeshkirad H. The effects of upper lip height on smile esthetics perception in normal occlusion and nonextraction, orthodontically treated females. Indian J Dent Res [serial online] 2008 [cited 2020 Feb 26 ];19:204-207
Available from: http://www.ijdr.in/text.asp?2008/19/3/204/42951


Full Text

A paramount objective of modern orthodontic therapy is the improvement of facial esthetics. The smile is one of the most effective means by which people convey their emotions. [1] Usually orthodontic patients evaluate treatment outcomes in terms of their smiles and overall enhancement in their facial appearance. Although orthodontic treatment is based primarily on occlusal relationships, greater attention is now paid to enhancing dentofacial characteristics such as the smile. Thus, it seems worthwhile to outline the common denominators of an esthetically pleasing smile, which is often a primary reason for seeking orthodontic care. [2]

The esthetics of a smile are influenced by such features as the amount of gingival display and the incisors. A smile demonstrating minimal gingival display has been deemed to be more esthetic than a smile with excessive gingival display. [3],[4],[5]

In 1970, Hulsey examined the influence of upper lip height on smile attractiveness and concluded that the most attractive smiles have the upper lip at the height of the gingival margin of the upper central incisors. [1] On comparing frontal facial features in repose and animation, Rigsbee et al, concluded that in an attractive smile, the upper lip elevated to reveal 10 mm of maxillary incisors and that orthodontically treated subjects displayed more maxillary incisors and gingiva than the untreated group. [6]

Peck and Peck also noted that the location of the gingival smile line largely depended on the subject's sex. On average, the smile line in women was found to be 1.5 mm higher than in men. [7]

Isiksal et al, demonstrated that smile esthetics were no different in subjects with ideal occlusions or Class I patients treated with or without extraction. They also noted that maxillary gingival display has a definite effect on smile esthetics. [2]

Maulik and Nanda also concluded that orthodontically treated group had more subjects displaying high anterior smile height compared with the untreated group. [8]

According to a study by Parekh et al, care should be taken not to produce an excessively flat smile arc during orthodontic treatment. [9]

Kokich et al, demonstrated that general dentists, orthodontists and lay people detect specific dental discrepancies to different extents. Orthodontists were more perceptive to altered dental esthetics than general dentists who in turn, were more perceptive than lay people. The authors discovered that the preferences for shape, symmetry and proportion of the maxillary central incisors differed significantly in the three groups. [5]

Roden-Johnson et al, concluded that lay people have no preference for smile esthetics in treated or untreated patients. [10]

The purpose of this study is to compare the esthetics of the smile in nonextraction orthodontic patients with a control group with normal occlusion and to statistically determine upper lip height in the two groups. We will also discuss how this feature relates to smile esthetics.

 Materials and Methods



Sixty-three women in the 20-30 years' age group were enrolled for this case-controlled study of which 30 had nonextraction, orthodontically treated occlusions and 33 had normal occlusions. Approval for the study was given by the University of Mashhad Ethics Committee.

Thirty-three normal occlusion females from the Mashhad Dental School, who had Class I molar and canine occlusion and good anterior alignment volunteered to be photographed while smiling. The remaining 30 subjects were selected from the archives of the Orthodontics Department of Mashhad Dental School and close-up images were taken of them. Nonextraction subjects also had good alignment of the anterior teeth and Class I molar and canine relationships.

After the subject's head was oriented into Natural Head Position, five black and white photos were taken of each subject so that we could choose an unforced, natural smile.

In this position, the focal plane was 465 mm from the soft tissue with the camera lens focused on the lips. The subjects were asked to smile and the film was exposed during the smile. These photographs were then scanned and converted to slides in PowerPoint for projection onto a large screen.

The evaluating panel consisted of two orthodontists, two general dentists, two laypersons, two adolescents with no history of orthodontic treatment and two students of dentistry. The male:female ratio was kept at 1:1 to eliminate gender bias. The ages of the panel members varied from 16 to 56 years.

The raters were told that they would see 63 slides of smiling patients. They were asked to rate the attractiveness of the smiles on a 100-point scale with 1-20 as poor, 21-40 as fair, 41-60 as good, 61-80 as very good and 81-100 as excellent. The raters were shown each of the 63 slides in random order for ten seconds. Each rater made his or her evaluation privately with no information about the subjects.

Panel members were asked to reevaluate the entire sample five weeks later. The second evaluation by all the panel members was found to be in the range of good repeatability (P 7.0.

As the upper lip height is a proportion, this measurement cannot be affected by magnification differences. The upper lip height was measured by means of a scale relating the upper lip height to the length of the upper central incisor's clinical crown.

Upper lip height had five scores that were measured as follows:

Score of -2: Condition in which the upper lip height was located two thirds of the upper central incisor's clinical crown superior to its gingival margin (estimate).

Score of -1: Condition in which the upper lip height was located one third of the upper central incisor's clinical crown superior to its gingival margin (estimate).

Score of 00: Condition in which the height of the upper lip was at the same level as the gingival margins of the upper central incisors.

Score of +1: Condition in which the upper lip height was a third of the distance between the clinical crowns of the upper central incisors and their gingival margins (estimate).

Score of +2: Condition in which the upper lip height was two thirds of the distance between the clinical crowns of the upper central incisors and their gingival margins (estimate).

The upper lip height was assessed for each smile and mean rated scores were calculated in normal occlusions and nonextraction, orthodontically treated patients.

The Mann-Whitney test was used to compare upper lip height in normal occlusion and nonextraction, orthodontically treated females.

ANOVA was also used to compare smile esthetics and differences between the two groups.

In all tests, P [1]

He also stated that the mean rated smile scores of orthodontically treated subjects were significantly poorer than the mean rated smile scores of subjects with normal occlusions.

The findings of the present study partially agree with Hulsey's study. This study showed that there were no differences in the attractiveness of the smiles of normal occlusion and nonextraction, orthodontically treated females.

In contrast, Mackley concluded in an unjust criticism of orthodontic treatment, that people with ideal occlusions who have had no orthodontic treatment have more attractive smiles. [4] In our study, neither the treatment group nor the control group was seen as having excellent smiles.

These data corroborate the findings of Isiksal who found no difference in smile esthetic scores between normal occlusion and nonextraction patients. He also demonstrated that the greater the maxillary gingival display, the lower the esthetic score. [2]

Some authors concluded that the upper lip should be at the height of the gingival margin of the maxillary central incisors in an attractive smile.

Our study revealed no statistically significant differences in smile esthetics in subjects with normal occlusions and in patients treated without extractions.

 Conclusion



Nonextraction orthodontic treatment has no predictable effect on the overall esthetic assessment of a smile.Upper lip height has no effect on the rating of smiles in nonextraction and in normal occlusion females.

 Acknowledgments



This research was supported by Mashhad Dental School Research Center and Vice Chancellor of Research of Mashhad University of Medical Sciences.

References

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