Nigerian Journal of Clinical Practice

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 22  |  Issue : 2  |  Page : 162--166

Influence of age, gender, and educational background on tooth color


MG Demirel1, MT Tuncdemir2,  
1 Department of Prosthodontics, Dentistry Faculty, Necmettin Erbakan University, Konya, Turkey
2 Department of Restorative Dentistry, Dentistry Faculty, Necmettin Erbakan University, Konya, Turkey

Correspondence Address:
Mr. M G Demirel
Department of Prosthodontic Dentistry, Necmettin Erbakan University, Dentistry Faculty Ankara St., 74/A, Konya
Turkey

Abstract

Introduction: The purpose of this study was to determine the effect of age, gender, and educational background on the color coordinates of the maxillary central incisor. Materials and Methods: The color of the maxillary central incisor teeth of 302 individuals was measured using a spectrophotometer. The L*, a*, and b* parameters were recorded. T-tests, analysis of variance (ANOVA), and the Scheffe's post-hoc tests were used to describe the relation of the L*, a*, and b* values between color with age, gender, and educational background. Results: The results of this study showed that a significant difference among all three parameters of color and age was observed. There was a significant difference for the a* and b* parameters for gender, but no difference was found for the L* parameter. Finally, there was a significant difference in the L* and a* parameters, but no difference in the b* parameter in terms of educational background. Conclusions: As individuals age, their tooth color darkens. Women have lighter teeth than men. The tooth color of high school graduates was found to be lighter than that of the other groups.



How to cite this article:
Demirel M G, Tuncdemir M T. Influence of age, gender, and educational background on tooth color.Niger J Clin Pract 2019;22:162-166


How to cite this URL:
Demirel M G, Tuncdemir M T. Influence of age, gender, and educational background on tooth color. Niger J Clin Pract [serial online] 2019 [cited 2019 Feb 17 ];22:162-166
Available from: http://www.njcponline.com/text.asp?2019/22/2/162/251793


Full Text



 Introduction



As a result of declining caries prevalence today, functional dentistry has shifted to aesthetic dentistry. Aesthetic appearance and social perception are now more important to people than oral function or health.[1] This is probably due to people realizing the effects of dental appearance on aesthetics and starting to judge each other for this reason.[2]

The most noticeable areas in the facial region are the eyes and mouth.[3] The oral region plays a significant role when a person comes into contact with another person, and, for example, poor oral hygiene and unattractive teeth are distinguished by others.[4] That is why dental appearance is very important for self-conscious people. These people pay attention to their oral hygiene in general, make efforts to make themselves look better, and usually have more attractive teeth.[5]

The color phenomenon is the capacity to reflect the light energy of an object and a psychophysical answer to the personal perception of the observer.[6] The color can be perceived differently depending on the light source, the observer being viewed, and the observer's perception of the object.[7]

Dental color is affected by intrinsic color and the presence of external stains on the tooth surface.[8] Intrinsic color is associated with the light scattering and absorption properties of the enamel and dentine.[9] Extrinsic color is associated with the absorption of materials (e.g., tea, coffee, the side effects of medicaments) into the surface of the enamel and particularly the pellicle coating.[10]

The dentin layer incrassates with age. The volume of the pulp chamber is also reduced with age due to continuous secondary dentin deposition. The tooth color may also depend on the dentin thickness, dentin color, and volume of the pulp chamber.[11]

Gender is another factor that is significantly related with tooth color. In a certain age group, men's tooth shade values were found to be darker than those of women in the Nigerian population.[12]

The CIELAB color space represents a uniform color space. The three axes of this three-dimensional color space are L*, a*, and b *. The L* value is a measure of the lightness of the material and is scaled such that the perfect black L* value is 0 and the perfect white L* value is 100. The a* value is a measure of red (positive a*) or green (negative a*), and the b* value is a measure of yellow (positive b*) or blue (negative b*).[13] The a* and b* coordinates approach zero for neutral colors, but change as the color saturates or intensifies.[5] The advantage of the CIELAB system is that color differences can be expressed in accordance with the visual perception and clinical situation.[14]

There have been studies about this subject,[15],[16],[17] but individuals' educational background has not been discussed yet. Moreover, none of these studies has focused on Turkish people. The purpose of this study is to investigate the effect of age, gender, and educational background on tooth color, and the null hypothesis is that age, gender, and educational background will not affect the color.

 Materials and Methods



The ethical committee of the Necmettin Erbakan University granted permission to conduct the study (number 2017/06). The consent form was approved by all patients. The maxillary central incisor was used for shade matching. The following exclusion criteria were used for the selection of patients: gingival problems, a history of any traumatic injury, the presence of excessive abrasion, dental malocclusion, a history of orthodontic or bleaching treatment, observable tooth staining, caries, and composite fillings on the facial surfaces of the teeth.

The natural maxillary central incisors of a sample of 302 individuals (n = 119 male, n = 183 female) were measured [Figure 1]. For the purposes of the study, the patients were divided into three age subgroups [young, ≤35 years (n = 177) –59%; middle-aged, 35–54 years (n = 102) –34%; old, ≥55 years, (n = 23) –7%], three educational background subgroups [college (n = 143) –47%; high school (n = 83) – 28%; primary school (n = 76) –25%].{Figure 1}

Color measurements were carried out by an experienced clinician using a Vita Easyshade spectrophotometer (Vita Easyshade V; Vita Zahnfabrik) [Figure 2] according to the manufacturer's instructions. This digital shade-matching device, which uses D-65 illumination for color selection, was subjected to a verification test to assess its reproducibility and reliability. In accordance with the manufacturer's instructions, an infection control shield was placed on the probe tip and calibrated before each measurement. To ensure standardization of the procedure, the probe was placed in the middle third of the labial tooth surface [Figure 3] and all measurements were performed under artificial light conditions in the same dental clinic. The L*, a*, and b* variables were recorded [Figure 4].{Figure 2}{Figure 3}{Figure 4}

The data were analyzed using the SPSS 10.0 statistical software (SPSS Inc., Chicago, IL, USA). The t-test was used for the gender subgroups, and the age and educational background subgroups were analyzed with the one-way analysis of variance (ANOVA) and the Scheffe's post-hoc test at a significance level of 0.05.

 Results



[Table 1] shows a significant difference between all three of the L*, a*, and b* parameters among different age groups. According to the Scheffe's test conducted to determine which groups differed from each other, all three of the L*, a*, and b* parameters showed a significant difference between the young and middle-aged groups and between the young and old groups, but there was no significant difference between the middle-aged and old groups. [Table 2] shows that a significant difference was found for the a* and b* values and more differences were found in males than females.{Table 1}{Table 2}

In this study, although there was a significant difference between the L* and a* parameters of the patients with different education levels, no significant difference was found in the b* parameter, as seen in [Table 3].{Table 3}

According to the Scheffe's test conducted to determine which groups differed from each other, the L* and a* parameters showed a significant difference between the high school and primary school levels, but there was no significant difference between the college and high school levels and the college and primary school levels. Additionally, no significant difference was found for the b* parameter.

 Discussion



The null hypothesis, that age, gender, and educational background will affect the color, was not accepted. Any of the factors investigated affected at least one color parameter. Thus, it can be concluded that age, gender, and educational background affect tooth color.

A significant difference was observed in all of the L*, a*, and b* parameters for the age subgroups (P < 0.05). An increase in L* value means that the tooth color is approaching absolute white, and, as the age increases, the brightness value decreases. In all age groups, the value of the a* parameter was found to be more than zero (i.e. the red tone was generally more dominant than the green tone, and when age increased, the redness also increased). In all age groups, the value of the b* parameter was found to be more than zero; in other words, yellow was the dominant tone, and we can assert that yellowness also increased with age. There was a significant difference between the younger group and the other age subgroups for all of the L*, a*, and b* parameters, but no significant difference was found between the middle-aged and old subgroups.

Although the L* parameter for the gender subgroup was not significantly different, the a* and b* parameters were significantly different (P < 0.05). It was also evident that the white tone of men's teeth was similar to women's, but it appeared darker because the yellow and red tones were stronger.

A significant difference was found for the L* and a* parameters, but no significant difference was found for the b* parameter in the educational background subgroups. Additionally, a significant difference was found between the educational background subgroups for both the L* and a* parameters between the high school and primary school levels, but no significant difference was observed between the other subgroups. In fact, a significant difference between the college graduate subgroup and the other subgroups was expected. However, in this study, individuals who already had a college education were included in the high school graduate group. This problem may have occurred because this young group was not in the college subgroup instead of the high school subgroup, but this should be the subject of another study.

Hasegawa et al. reported that a tendency to decrease in lightness and to increase in yellowness with advancing age but the difference of tooth color between male and female could not be distinguished.[18]

Gozalo-Diaz et al. reported that the color tone of the central incisors became darker, redder, and yellower when age increased; they also found that women's central incisors were lighter and less yellow than men's.[17]

Goodkind and Schwabacher reported that women on an average have lighter, less reddish, and more yellow teeth. Also teeth tend to become darker and more reddish with advancing age.[11]

Other previous studies examining the effect of age and sex on tooth color; although similar results were found for age–tooth color relationship,[7],[12],[15],[19] no significant similarity was found for gender–tooth color relationship.[12],[15],[19]

Although there is no similarity between the measured ethnic groups, age ranges, or the methods used for color measurement, all studies have reached the conclusion that the color has darkened as the age increases in previous studies.[7],[11],[12],[15],[16],[18],[19] Therefore, regardless of the conditions change, it can be said that as the age increases, the color of the teeth will be darkened.

The results of this study showed similar results to previous studies for age subgroups. However, the same consensus was not established for gender subgroups. In studies not found a significant relationship between gender and teeth color, it is noteworthy that guide tabs are used for color measurement.[12],[15],[19] On the other hand, there were significant differences between gender and tooth color in the studies using color measuring devices for color measurement.[11],[16],[18] The reason of this outcome may be the teeth color difference between men and women are less, and the inability of the human eye to perceive this slightly difference.

The results of this study showed similar results to previous studies measuring tooth color with measuring devices for gender subgroups.

Many systems have recently been used to measure tooth color. These include visual subjective comparisons using the shade guide tabs or instrumental objective measurements using spectrophotometers, colorimeters, and image analysis techniques with cameras.

Choi et al. concluded that the digital analysis of the tooth color is more accurate and reproducible than a visual assessment.[20] VITA Easyshade V is a spectrophotometer for tooth shade matching. It facilitates color determination for natural teeth. Spectrophotometers measure one wavelength at a time from the reflectance or transmittance of an object and have been used to measure the visible spectrum of teeth.[21]

This study has several limitations. First, measurements were always made with the same instrument. In addition, increasing the number of samples would increase the accuracy of the study, which would give more significant results for the statistical analyses. Furthermore, the assessment of the individuals who already have a college education in a separate group could have led to more significant results.

 Conclusions



Along with the limitations of this study, when the age increased, the teeth became darker, yellower, and redder. Women had lighter and less yellow central incisors than men. The central incisors of primary school graduate subjects were darker and yellower than those of high school graduates.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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