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Table of Contents   
ORIGINAL RESEARCH  
Year : 2011  |  Volume : 22  |  Issue : 2  |  Page : 242-247
Perception differences of altered dental esthetics by dental professionals and laypersons


Department of Orthodontics and Dentofacial Orthopedics, Sri Sai College of Dental Surgery, Vikarabad, Andhra Pradesh, India

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Date of Submission16-Nov-2009
Date of Decision06-May-2010
Date of Acceptance10-Nov-2010
Date of Web Publication27-Aug-2011
 

   Abstract 

Background: When we smile, our smile could often become the target of close scrutiny by the person you are smiling at. A trained eye readily detects any asymmetricity or any aspect of that smile which may be out of balance, or disharmonious with its environment. The purpose of this study was to determine whether any such asymmetric or symmetric dental discrepancies were detectable by various groups of evaluators.
Aims: The aim was to determine whether asymmetric and symmetric anterior dental discrepancies were detectable by orthodontists, general dentists, and laypersons, and to establish threshold levels for several specific aesthetic criteria that could be used by orthodontists and general dentists as an aid in the treatment planning.
Materials and Methods: Three images of smiles were intentionally altered with a software-imaging program. The alterations involved the crown length, crown width, midline diastema, and the papillary height of the maxillary anterior teeth. These altered images were then rated by groups of general dentists, orthodontists, and laypersons using a visual analog scale. Statistical analysis of their responses resulted in the establishment of threshold levels of attractiveness for each group.
Results: The orthodontists were more critical than the general dentists and laypersons when evaluating asymmetric crown length discrepancies. All three groups could identify a unilateral crown width discrepancy of 2.0 mm. A small midline diastema was not rated as unattractive by any group. Reduction of papillary height was generally rated as less attractive.
Conclusions: Asymmetric alterations make teeth more unattractive not only to the dental professionals, but also to laypersons.

Keywords: Aesthetics, smile, perception

How to cite this article:
Thomas M, Reddy R, Reddy B J. Perception differences of altered dental esthetics by dental professionals and laypersons. Indian J Dent Res 2011;22:242-7

How to cite this URL:
Thomas M, Reddy R, Reddy B J. Perception differences of altered dental esthetics by dental professionals and laypersons. Indian J Dent Res [serial online] 2011 [cited 2019 Oct 14];22:242-7. Available from: http://www.ijdr.in/text.asp?2011/22/2/242/84295
The word ''Esthetics'' is derived from the Greek word αισθητική (Transliterated: aisthitiki) meaning ''perception.'' It deals with the aspect of beauty and things beautiful. Beauty has two dimensions: objective and subjective. Objective (admirable) beauty is based on the consideration of the object itself, implying that the object possesses properties that make it unmistakably praiseworthy. Subjective (enjoyable) beauty is a quality that is value-laden, relative to the tastes of the person contemplating it. [1]

Facial appearance often plays a vital role in forming an impression of others, especially during the initial stages of acquaintance. The impression one gets of the other person during this initial encounter is often a long lasting one and could be either positive or negative at different times. Looks, however, play an important role during this first impression. While it has been the desire of most individuals to look good and presentable, it has been their ''smile'' that often ends up either enhancing or spoiling the looks of that person. This has, indeed, been the quest of orthodontists the world over to provide that ideal make over for those who are less fortunate. The orthodontic profession has always been in pursuit of the ideal dentition.

A century ago, the orthodontic paradigm was geared toward achieving optimal proximal and occlusal contacts of the teeth within the framework of a balanced profile. When cephalometric-based diagnosis and treatment planning hit full stride in the 1950s and 1960s, esthetics in orthodontics was defined primarily in terms of the profile. [2] The present emphasis, however, is toward enhancing facial esthetics and creating a beautiful smile.

Several studies have evaluated esthetic perception of different malocclusions. Even indices have been created to measure dental esthetics based on a relatively standardized set of variables. These indices assess treatment need, based on occlusal health but do not focus directly on anterior dental esthetics. [3]

It is a known fact that the orthodontist's perception often differs from that of other professionals and laypersons. This fact has already been well established. However, we find that these established parameters have been carried out among the western population. In order for these parameters to be acceptable for the Indian population, it was necessary to find out whether these smile parameters established for western population were acceptable for the Indian population as well. Hence, this study was aimed at evaluating the opinion of general dentists and laypersons in addition to orthodontists. The hypothesis of the study states that laypersons would find it a bit more difficult to discriminate between asymmetric levels of discrepancies compared to general dentists and orthodontists. The purpose of this study was to evaluate whether asymmetric and symmetric anterior dental discrepancies were detectable by orthodontists, general dentists, and laypersons along with the establishment of threshold levels for several specific esthetic criteria that could be used by orthodontists and general dentists as an aid in treatment planning.


   Materials and Methods Top


This study was conducted at the Department of Orthodontics and Dentofacial Orthopaedics, Sri Sai College of Dental Surgery, Vikarabad.

Materials

The following materials were used in the study.

  • Digital camera [Nikon D80 Digital camera [effective pixels 10.2 mega pixels DX format Image sensor RGB CCD, 23.6Χ15.8 mm; total pixels 10.75 million (1.5Χ FOV crop)]: It is used to take the digital Photographs of the samples.
  • Laptop Dell Inspiron 1420 [Processor 2.0 GHz Intel Core 2 Duo T7300, Memory 2 GB, 667 MHz DDR2, Hard Drive 160 GB 5400 r/min, Chipset Intel 965, Graphics Nvidia GeForce 8400M GS, Operating System Windows Vista Premium, Display 14.1 in. (1440Χ900)]: The captured digital Photographs were transferred from the camera to the laptop.
  • Adobe Photoshop, version 7 [Adobe Systems Inc., San Jose, CA, USA]: This software is used to alter the Photographs.


Method used for obtaining images

Digital Photographs showing the smile of the subjects (students of the college) were taken by a single operator, while the subjects were in a relaxed position. The Photographs were taken at a fixed distance of 60 cm from the object. Part of the face that was captured was restricted to that of the chin below and the ala of the nose above to decrease the compounding parameters. However, there was no zooming done. The camera was tripod mounted while all the Photographs were taken in true day light.

The nose and chin were eliminated from the images to reduce the number of confounding variables.

Inclusion criteria

Inclusion criteria are as follows.

  • Subjects having normal class I occlusion as specified by Andrews in his six keys, [4] which include normal class I molar relationship, absence of tooth rotations, tight interdental contacts, and level curve of Spee.
  • Subjects not having undergone any kind of orthodontic treatment previously.


The images were altered for the following four esthetic parameters based on Kokich's approach:

  • Crown length
  • Crown width
  • Midline diastema
  • Height of papilla. [5]


These altered images were then rated using a visual analog scale by three groups of individuals (100 individuals per group with a male:female ratio of 57:43 in the laypersons group, 65:35 in the general dentists group and 73:27 in the orthodontists group) by means of a slide show shown in the afternoon after a brief introduction about esthetics. Informed written consent was taken from the subjects and the approval from the ethics committee was sought prior to the study.

  • Laypersons (average age 20-40 years with a basic education level of +2).
  • General dentists (average age 30-40 years).
  • Orthodontists (average age 30-40 years and having a minimum clinical experience of 3 years).


To test the hypothesis, the three above groups rated each of the four esthetic parameters mentioned earlier, where each esthetic parameter consisted of five variants that were morphed using the Adobe Photoshop. Each smile was intentionally altered for all those parameters, which were most common in anterior esthetic discrepancies that were also based on their frequency and clinical significance to smile.

The crown length of the maxillary central incisor was altered. The crown was shortened in 0.5 mm increments by adjusting the level of gingival margin. The reference points for these measurements were the most superior points on the labial gingival margin of the adjacent lateral and central incisors. The incisal edges were maintained at the same level to simulate super eruption of the central incisor and concomitant incisal wear of that particular incisor selected [5] [Figure 1]a-e.
Figure 1 (a-e): The crown length of the maxillary central incisor shortened in increments of 0.5mm

Click here to view


The alteration of crown width was done to a lateral incisor, as it is the most common tooth, which is affected by the size of tooth. The width of lateral incisor was reduced in increments of 1 mm, while maintaining the gingival margin at the same level. The relative measurements were made at the widest part of the crown between interproximal contact points [Figure 2]a-e.
Figure 2 (a-e): The crown width of the maxillary lateral incisor reduced in increments of 1mm

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A midline diastema, which is the spacing between two upper central incisors, was created incrementally between the central incisors. The spacing was widened progressively in 0.5 mm increments. The measurements were made at the interproximal contact points between the central incisor crowns [Figure 3]a-e.
Figure 3 (a-e): The midline diastema widened progressively in 0.5mm increments between the maxillary central incisor crowns

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Papillary height was altered symmetrically between the maxillary anterior teeth by progressively lengthening the interproximal contact points in 0.5 mm increments in a gingival direction between all maxillary anterior teeth. The natural tooth shape and papillary form was maintained [Figure 4]a-e.
Figure 4 (a-e): Symmetric alteration of the papillary height by progressively lengthening the interproximal contact points in 0.5 mm increments in a gingival direction between all maxillary anterior teeth

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All the 20 altered smile photographs (five variants each of the four esthetic parameters) were grouped randomly but in such a way that different variables were presented on each page of the questionnaire so that intra and inter parameter variations were minimized. Copies of the original questionnaire were distributed among all the three groups.

A visual analog scale (VAS) graded from 1 to 10 was used for the ratings and was presented below the questionnaire. The scale progressed one end to the other from ''very pleasing'' to ''unpleasing.'' Each rater was asked to mark a point along the scale according to his or her perception of dental esthetics.

Statistical methods

The VAS scores rated by all the groups were analyzed to find out the mean and standard deviation of all twenty altered smile Photographs. These were used for the statistical comparison using the one-way analysis of variance (ANOVA) test for comparison between all groups; post hoc test for multiple comparisons between all the groups was also employed.


   Results Top


The statistical tests used were ANOVA and post hoc tests, initially the mean was found of each group and an ANOVA test performed to compare all parameters between the groups, and later Mann-Whitney test (post hoc) was used to compare the parameters within each group.

An ANOVA test was conducted in each group to assess how the groups rated each level of deviation. Significant overall tests were followed with a series of post hoc multiple comparisons to test hypotheses. Multiple comparisons between each level of variation were used to determine the level of deviation at which each group discriminated between esthetic and less esthetic dental features.

The assessment for all the four parameters has shown a significant difference in perception by all three groups. The multiple comparison tests showed the difference in perception within the groups. [Table 1] describes the mean and standard deviation for all the four parameters. [Table 2] shows ANOVA test of all four parameters between groups, and [Table 3] denotes post hoc test of all four parameters between and within the groups.
Table 1: The mean and S.D. for all the four parameters


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Table 2: ANOVA test of all four parameters between groups


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Table 3: Post hoc test of all four parameters between and within groups Post hoc tests


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Crown length

  • The general dentists showed a lesser threshold level for the unattractiveness of crown length, than did the other groups (mean of 4.8 and S.D. of 1.4) [Table 1].
  • The orthodontists were more critical in identifying the discrepancy under this esthetic parameter (mean of 4.5 with S.D. of 1.1) than the other groups [Table 1].
  • The ANOVA test showed that all the three groups rated this parameter as unattractive (significant value of 0.41) [Table 2] compared to the other three esthetic parameters.
  • The discrepancy of this parameter was more easily recognized by orthodontists than the other groups (mean difference of 0.037) [Table 3].
  • However, the multiple comparison tests showed no significant value between the groups [Table 3].


Crown width

  • The orthodontists were more critical in identifying the discrepancy in this esthetic parameter (mean of 4.5 with S.D. of 1.1) than the other groups [Table 1].
  • The multiple comparison tests showed no significant value between all the three groups [Table 3].


Midline diastema

  • In this parameter, orthodontists identified the discrepancy to be unattractive (mean of 3.9 with S.D. of 0.9) [Table 1].
  • The ANOVA test revealed that all the three groups rated this parameter as unattractive (significant value of 0.41) [Table 2] compared to the other four esthetic parameters.
  • There was no significant difference in relation to midline diastema between the groups as shown by the multiple comparison tests [Table 3]


Papillary height symmetry

  • The discrepancy of this parameter was more recognized by orthodontists than the other groups (mean difference of 0.037) [Table 3].
  • There was no significant difference in the perception compared to other parameters [Table 2].



   Discussion Top


It is a well-known fact that the perception of orthodontists often differs from that of the perception of other professionals and laypersons, and that the esthetic perception could differ for different ethnic groups as well. Though many researchers, including Bjorn Zachrisson, Sheldon Peck, and Vincent Kokich have proposed various parameters for esthetic smiles. [1],[5],[6] While most of these studies were carried out in the western population, there have been very few studies including the study done by

Krishnan et al. [7] carried out in the Indian environment. Hence, it was necessary to find out if the parameters established for the western population were also acceptable for the Indian population. Hence, there was a need felt, to evaluate how the orthodontists, general dentists, and laypersons judged these parameters in the Indian context.

This study has shown significant differences for several esthetic parameters. Very few studies have established threshold levels of noticeability of various esthetic parameters by orthodontists, general dentists and the laypersons. [3],[5],[8]

Contrary to the present study, orthodontists during previous studies [1],[3],[5],[9],[10] found the discrepancy in crown length to be more unattractive.

According to orthodontic perspective, the normal width of a lateral incisor is important for achieving a better esthetic result while restoring a peg shaped lateral incisor or the decreased width of the tooth, however in the present study it was found that the crown width changes were not significant in all three groups and this finding matches with the result of Bhukary et al. [11] and others. [3],[5],[12]

In the present study, however, the orthodontists identified the midline discrepancy to be more unattractive which again is in accordance to the studies that have been done on esthetic discrepancies. [1],[3],[13],[14],[15] This study also shows that the correction of midline diastema is an important aspect recognized both by the orthodontist and the layperson as well.

Also in this study the discrepancy of papillary height symmetry was spotted more by orthodontists than the other groups as was shown in earlier studies. [1],[3],[5],[16] The level of papilla should be maintained to prevent either the black triangle appearance or the increased length of clinical crown. Therefore, maintaining the papillary height is an important factor from the orthodontic perspective.

As the orthodontists recognize specific dental esthetic parameters more readily than the layperson or even the general dentist except when it comes to the crown length, both the general dentists and the laypersons seemed to have a similar level of threshold for assessing the midline diastema. Even though both orthodontists and general dentists were able to detect discrepancies at the same level for papillary height, the orthodontists, however, were able to identify crown width, midline diastema, papillary height at a smaller level of deviation than both the general dentists and the layperson.

The level of detection of various anterior esthetic parameters differed according to the parameter and the responding group. The findings revealed that all the three groups found midline diastema to be more unattractive. General dentists rated variation in crown length to be more unattractive than the other two groups where as orthodontists found crown width, and papillary height as being more unattractive.

Even though the ratings of different judges varied, there was an understanding ability of identifying the positive and negative attributes of an acceptable smile according to each group. Orthodontist's perception differed slightly for acceptance with respect to crown width and papillary height. General dentists differed with respect to crown length. However, there was a similarity between the perceptions in remaining parameters. When we see in an overall sense of perception, esthetic judgments did not vary in the Indian context.

Results of this study showed that the perception of orthodontists varied from the perception of other professionals. The overall acceptance of smile parameters showed that an acceptable smile should have no asymmetry of crown length, crown width and papillary height with absence or minimal of midline diastema. Clinical implications of the findings from this study can have significant influence on diagnosis and treatment planning in the orthodontic treatment.

The main limitations of the study were consideration of anterior dental esthetics alone and the probability of individual variations changing the results.


   Summary and Conclusion Top


The conclusions from this study are:

  • Asymmetric alterations make teeth more unattractive not only to dental professionals but also to laypersons.
  • Symmetric alterations might appear unattractive to dental professionals, but the laypersons group often did not recognize some symmetric alterations.
  • Orthodontists were able to identify crown width, midline diastema and papillary height at a smaller level of deviation than general dentists and the laypersons. Hence, these parameters should be taken into consideration during orthodontic treatment plan.
  • Among all the four esthetic parameters, midline diastema was more unattractive for all the groups. So, correction of this parameter by the dental professional is of paramount importance for a better esthetic result.


Since this study gives an insight into the perception of esthetics by orthodontists, general dentists and the laypersons, a detailed clinical examination of smile parameters should be stressed upon in the orthodontic protocol before planning any kind of an orthodontic treatment, to give the best possible smile for the patients.

 
   References Top

1.Zachrisson BU. Esthetic factors involved in anterior tooth display and the smile: Vertical Dimension. J Clin Orthod 1998;32:432-45.  Back to cited text no. 1
    
2.Ackerman JL, Proffit WR, Sarver DM. The emerging soft tissue paradigm in orthodontic diagnosis and treatment planning. Clin Orth Res 1999;2:49-52. Sited from Nanda R. Biomechanics and esthetic strategies in clinical orthodontics. 1 st ed. Connecticut: Elsevier Saunders; 2005.  Back to cited text no. 2
    
3.Kokich VO, Kiyak HA, Shapiro PA. Comparing the perception of dentists and lay people to altered dental esthetics. J Esthet Dent 1999;11:311-24.  Back to cited text no. 3
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4.Andrews LF. The six keys to normal occlusion. Am J orthod 1972;63:296.  Back to cited text no. 4
    
5.Kokich VO, Kokich VG, Kiyak HA. Perceptions of dental professionals and laypersons to altered dental esthetics: Asymmetric and symmetric situations. Am J Orthod Dentofacial Orthop 2006;130:141-51.   Back to cited text no. 5
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6.Peck S, Peck L, Kataja M. Some vertical lineaments of lip position. Am J Orthod Dentofacial Orthop 1992;101:510-24.  Back to cited text no. 6
    
7.Krishnan V, Daniel ST, Lazar D, Asok A. Characterization of posed smile by using visual analog scale, smile arc, buccal corridor measures, and modified smile index. Am J Orthod Dentofacial Orthop 2008;133:515-23.  Back to cited text no. 7
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8.Flores-Mir C, Silva E, Barriga MI, Lagravere MO, Major PW. Lay person's perception of smile aesthetics in dental and facial views. J Orthod 2004;31:204-9.  Back to cited text no. 8
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9.Kokich V. Esthetics and anterior tooth position: An orthodontic perspective. Part I: Crown length. J Esthet Dent 1993;5:19-23,200-7.  Back to cited text no. 9
    
10.Soh J, Chew MT, Wong HB. A comparative assessment of the perception of Chinese facial profile esthetics. Am J Orthod Dentofacial Orthop 2005;127:692-9.  Back to cited text no. 10
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11.Bukhary SMN, Gill DS, Tredwin CJ, Moles DR. The influence of varying maxillary lateral incisor dimensions on perceived smile aesthetics. Br J Orthod 2007;203:687-93.  Back to cited text no. 11
    
12.Pinho S, Ciriaco C, Faber J, Lenza MA. Impact of dental asymmetries on the perception of smile esthetics. Am J Orthod Dentofacial Orthop 2007;132:748-53.  Back to cited text no. 12
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13.Kokich V. Esthetics and anterior tooth position: An orthodontic perspective. Part III: Mediolateral relationships. J Esthet Dent 1993;5:200-7.  Back to cited text no. 13
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14.Johnston CD, Burden DJ, Stevenson MR. The influence of dental to facial midline discrepancies on dental attractiveness ratings. Eur J Orthod 1999;21:517-22.  Back to cited text no. 14
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15.Gul-e-erum, Fida M. Changes in smile parameters as perceived by orthodontists, dentists, artists, and laypeople. World J Orthod 2008;9:132-40.  Back to cited text no. 15
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16.Lavacca MI, Tarnow DP, Cisneros GJ. Interdental papilla length and the perception of aesthetics. Prac proc aesth den 2005;17:405-12.  Back to cited text no. 16
    

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Correspondence Address:
Mayuri Thomas
Department of Orthodontics and Dentofacial Orthopedics, Sri Sai College of Dental Surgery, Vikarabad, Andhra Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9290.84295

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]

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