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DENTAL SCIENCE - ORIGINAL ARTICLE
Year : 2015  |  Volume : 7  |  Issue : 6  |  Page : 632-635  

Assessment of perceptibility and acceptability of color variations between matched teeth among trainee dentist and lay person


1 Department of Prosthodontics, Adhiparasakthi Dental College and Hospital, Melmaruvathur, India
2 Department of Pedodontics, Tagore Dental College, Tamil Nadu, India
3 Anil Neerukonda Institute of Dental Sciences, Visakhapatnam, Andhra Pradesh, India

Date of Submission28-Apr-2015
Date of Decision28-Apr-2015
Date of Acceptance22-May-2015
Date of Web Publication1-Sep-2015

Correspondence Address:
Dr. A S Ramesh
Department of Prosthodontics, Adhiparasakthi Dental College and Hospital, Melmaruvathur
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-7406.163578

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   Abstract 

Aim: The aim of this study was to find the difference in perceptibility and acceptability of changes done to various color coordinates of matched teeth, between trainee dental surgeons, and lay person. Materials and Methods: A photograph with a set of matched central incisor teeth was selected. In one of the central incisors, the color coordinates (hue, value, and chroma) were altered to a preset value. These pictures were presented to trainee dental surgeons and lay person and their level of perception of color change and acceptance of color change was registered and compared. Results: It was found that trainee dental surgeons fared better in perceiving the color change and accepted less of the color changed specimens. The dimension of color that was more discerned both by lay person and trainee dental surgeons was value, hue, and last chroma. Conclusion: When compared to a lay person, dental surgeons are more acute in perceiving color changes and do not accept the color difference between teeth to a higher degree.

Keywords: Central incisors, chroma, color acceptability, color perceptibility, dimensions of color, esthetics and sensory threshold, hue, trainee dental surgeons, value


How to cite this article:
Ramesh A S, Sharma A, Rijesh K, Prakash R, Devi L, Raja E. Assessment of perceptibility and acceptability of color variations between matched teeth among trainee dentist and lay person. J Pharm Bioall Sci 2015;7, Suppl S2:632-5

How to cite this URL:
Ramesh A S, Sharma A, Rijesh K, Prakash R, Devi L, Raja E. Assessment of perceptibility and acceptability of color variations between matched teeth among trainee dentist and lay person. J Pharm Bioall Sci [serial online] 2015 [cited 2019 Aug 20];7, Suppl S2:632-5. Available from: http://www.jpbsonline.org/text.asp?2015/7/6/632/163578

Visual shade matching seems to be a skill acquired through clinical experience. This has been studied and stated by Verriest et al. [1] and Capa et al. [2] With the increasing popularity of esthetic restoration accurate shade matching has become essential to an optimal dental restoration and successful clinical practice. Image of self, very strongly influences patients in their decision to obtain treatment while 50% of remakes for esthetic restorations are result of failure to match shade accurately leading to unnecessary additional patient visit, dentist anguish, staff frustration, and lab remake fees. Correct shade choice is limited by knowledge of color science, clinical experience, time constraints, and patient cooperation. Visual color selection is dependent on many factors and variation in any of the can lead to an altered color perception. Though it is contended that the female gender can perceive color better, studies by Milagres show that male discern color better. [3]

Color has been described as a three-dimensional phenomenon, consisting of hue (color), value (brightness), and chroma (saturation). No single tooth is of uniform color. All teeth are the aggregate of number of hues and varying shades of the same hue. Due to the subjective nature of perceptual shade matching, the skill to match shades is acquired through knowledge of basic color principles and clinical experience thus making a lay person not credible as sole decision makers in shade selection.

Studies by Al-Wahadni et al., have shown that Patients are more satisfied with shade matching rather than the prosthodontists. [4] However, can this be generalized over the whole population and if so, how early is this ability acquired. Hence, a study was proposed to check for the effect at the grass root level. Hence, trainee dental surgeons were inducted into the program. The study was designed to find out the ability of trainee dental surgeons and lay person to differentiate color difference and to find the level of variation in color acceptable to them.

The aim of the study was to assess the perceptibility and acceptability of color variations between matched teeth among trainee dentist and lay person.


   Materials and Methods Top


On approval from Ethical Committee of Adhiparasakthi Dental College and Hospital, the study was started. Photographs of five different subjects with matched teeth were made using the digital single-lens reflex camera under high resolution. Using Adobe Photoshop, version 7 (Adobe Systems Inc., San Jose, CA, USA) color of one of the selected central incisor of one of the photographs (the other four were discarded) was modified in different the different dimensions of color that is, hue, value, chroma to predetermined levels (±2%, ±4%, ±6%, ±8%, and ± 10%). The contralateral central incisor was not modified and served as a control.

Hard copies of modified teeth were shown to trainee dental surgeons and lay person. Inclusion criteria being trainee dental surgeons of the selected institution and lay persons were people who visited the Department of Prosthodontics at Adhiparasakthi Dental College and Hospital. Person with a known history of color blindness, person above the age of 50 years, and person who were not willing were excluded from the study. After exclusion 100 CRRI and 100 lay persons participated in the study. Condition of each viewing session was standardized as much as possible. The task was performed in a spacious room with multiple windows to avoid fatigue and allow for optimal lighting conditions. Subjects viewed the photographs at a 30 cm distance.

The study was a multicentric double-blinded randomized control trial. The study is multicentric since it was conducted in five different centers, double-blinded since both the operator and assessors were not aware of the changes done to the photos and the key was kept aside till the end of the survey, randomized since the CRRI and lay person were selected at random with only the inclusion and exclusion criteria as guide, control trial as un-modified contralateral central incisor served as control. The responses of CRRI and lay person were collected on a survey form and were recorded for statistical analysis.


   Results Top


The result is as follows.

[Table 1] and [Figure 1] on values of Perceptibility of Change in Hue, Value and Chroma shows that lay person were able to perceive the change in Value more than ± 8%, hue more than ± 10% and chroma more than ± 10% and the trainee dental surgeons was able to perceive changes in value more than ± 2%, hue more than ± 8% and chroma more than ± 8%. This denotes that the trainee dental surgeons were able to perceive changes in value and chroma much more significantly than the Lay person.
Figure 1: Comparison of the perceptibility of various changes in dimensions of color by dental color rendering index and lay person

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Table 1: Dental CRI were able to perceive Hue, Value and Chroma better than Lay person

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[Table 2] and [Figure 2] on values of acceptability of change in Hue, value and chroma shows that as far as acceptance of color change is concerned, trainee dental surgeons were more critical in acceptance of changes as they did not accept changes in Value less than ± 4% , Hue less ± 8% than and chroma less than ±10%. Comparatively lay person did not accept color changes value less than ± 6%, Hue less ± 10% than and Chroma less than ± 10%.
Figure 2: Comparison of the acceptability of changes in various dimensions of color by dental surgeons and lay person

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Table 2: Lay person accepted color though it was different to a higher degree than dental CRI

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   Discussion Top

"Esthetics" is a Greek word meaning "perception." It deals with the various aspects of beauty. Beauty may be regarded in two ways: Objective and subjective. Objective beauty is based on the consideration of the object itself based on preconceived notions. Subjective beauty is a quality that is relative to the tastes of the person enjoying it. [5] 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 asymmetrical aspect of that smile. Color of the teeth is one such aspect. Perception and acceptance of such color changes may or may not be an inherent or trained trait.

Studies of Douglas et al. [6] have proved that among professionals, the perception of color change was higher. Studies have also proved that lay persons have a much higher tolerance level to variation in color. In a study by Al-Wahadni et al, they found that patients were more satisfied with the color matching of their porcelain-fused-to-metal crowns more than their prosthodontists. [4] This leads us to speculate on whether the patient input is really necessary for shade selection. Moreover, no study has been conducted to know as to how and when this ability of the dental surgeon blooms.

A study by Kijima et al., [7] it was noted that color discrimination was made firstly in terms of hue, secondly in terms of value, and thirdly in terms of chroma. However, they failed to discriminate as to by whom and to what degree.

It has been studied and stated by Barna et al. [8] "Color perception defectiveness cannot be overcome by any number of years of experience and color-defective dentists should obtain assistance when matching tooth shades".

Hence, the question as to how and when does this ability of the dental surgeon to perceive and discern this color difference develops. Is it through years of practice after qualification or much earlier? Hence, a study was designed to test the perceptibility and acceptability of color variations between matched teeth among trainee dentist and the common man.

A picture of a person's smile with matched central incisor was chosen. One of the central incisors was modified using Photoshop in the three dimensions of color viz. hue, value, and chroma to predetermined levels. (±2%, ±4%, ±6%, ±8%, and ± 10%). These modified photographs along with the unmodified picture were given to dental trainees and lay person and were asked to find out if they could discern the color change and what color they found acceptable.

The study shows that the dental trainee was able to perceive the color differences much better than lay person to a significant degree similar to those of Capa et al. [2] It was also found that acceptance level of mismatched color was much lower in dental trainee than a lay person. This proves that color perception is an acquired skill that starts much earlier in a dental surgeons life and may be honed through years of experience. Dental trainees were also more stringent on their acceptance of color variation to a significant level. This may be because of setting a higher standard for oneself to overcome any failure that could arise because of color difference. Later this practice becomes a learned trait. This learning is not about simple color perception but as put forth by Kyle et al, it may instead result from how adaptation alters the relative salience of the target. [9] This could also be because of perceptual grouping at a psychological level and, at the same time, outlines the mechanisms for grouping at the neurophysiological level as proposed by Pieter et al. [10]

Of the three-dimensions in color, both the dental surgeon and lay person were able to perceive changes in value more than hue. The least perceived change was chroma. This is consistent with the findings of Ratzmann et al. [11] who perceived similar results but varied from the studies of Kijima et al. [7] This could be due to increase in test subjects and the inclusion of Lay person in the study group.

Though both subject groups were able to perceive color change, acceptability of color also varied greatly. Both the groups were able to accept change done to chroma and hue to a greater degree than to changes done to value in that order. This could be attributed to the color perceiving sense of the eye.


   Conclusion Top


With the limited results, it can be concluded that the perception of color difference seems to be a learned trait. Whether it is enhanced by experience is still a question at large. As far as acceptance of color variation is concerned, dental surgeons are stricter and hence are a better judge. But still as beauty is in the eyes of the beholder, the final onus of color selection is on the subject themselves.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Verriest G, Van Laethem J, Uvijls A. A new assessment of the normal ranges of the Farnsworth-Munsell 100-hue test scores. Am J Ophthalmol 1982;93:635-42.  Back to cited text no. 1
[PUBMED]    
2.
Capa N, Malkondu O, Kazazoglu E, Calikkocaoglu S. Evaluating factors that affect the shade-matching ability of dentists, dental staff members and laypeople. J Am Dent Assoc 2010;141:71-6.  Back to cited text no. 2
    
3.
Milagres V, Teixeira ML, Miranda ME, Osorio Silva CH, Ribeiro Pinto JR. Effect of gender, experience, and value on color perception. Oper Dent 2012;37:228-33.  Back to cited text no. 3
    
4.
Al-Wahadni A, Ajlouni R, Al-Omari Q, Cobb D, Dawson D. Shade-match perception of porcelain-fused-to-metal restorations: A comparison between dentist and patient. J Am Dent Assoc 2002;133:1220-5.  Back to cited text no. 4
    
5.
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. 5
    
6.
Douglas RD, Steinhauer TJ, Wee AG. Intraoral determination of the tolerance of dentists for perceptibility and acceptability of shade mismatch. J Prosthet Dent 2007;97:200-8.  Back to cited text no. 6
    
7.
Kijima S, Henzan H, Niu ZY, Nakaura K, Kohchi T, Ishihara S, et al. Study of estimation of color recognition on the dentist. On the ability of subjects to discriminate color in terms of hue, value and chroma. Meikai Daigaku Shigaku Zasshi 1990;19:377-82.  Back to cited text no. 7
    
8.
Barna GJ, Taylor JW, King GE, Pelleu GB Jr. The influence of selected light intensities on color perception within the color range of natural teeth. J Prosthet Dent 1981;46:450-3.  Back to cited text no. 8
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9.
McDermott KC, Malkoc G, Mulligan JB, Webster MA. Adaptation and visual salience. J Vis 2010;10:17.  Back to cited text no. 9
    
10.
Roelfsema PR, Houtkamp R. Incremental grouping of image elements in vision. Atten Percept Psychophys 2011;73:2542-72.  Back to cited text no. 10
    
11.
Ratzmann A, Treichel A, Langforth G, Gedrange T, Welk A. Experimental investigations into visual and electronic tooth color measurement. Biomed Tech (Berl) 2011;56:115-22.  Back to cited text no. 11
    


    Figures

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    Tables

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