Evaluation of gingival melanin pigmentation in pediatric population- An observational study.

AIM: The aim of this study is to evaluate the gingival melanin pigmentation in the Indian pediatric population. The aim of this study is to find any association between age and melanin distribution, age and intensity of melanin distribution, sex and melanin distribution, sex and intensity of melanin distribution, skin tone and melanin distribution, skin tone and intensity of melanin distribution and finally the association between melanin distribution and intensity.
BACKGROUND: Pigmentation on the interdental papilla, attached and marginal gingiva is commonly found in various races across the world. There is lack of literature for documentation of the same in the pediatric population.
MATERIALS AND METHODS: Intensity of melanin pigmentation was observed by the gingival melanin pigmentation index (class 1- class 6) as given by Ponnaiyan et al. This cross-sectional, observational study was conducted in the Institution. 100 children were selected from the age group of 1-12 years of age. The association between the various parameters were verified using Chi square test.
RESULTS: With the findings of the present study, it can be concluded that the distribution of melanin pigmentation is not affected by age, sex and skin color. The intensity of melanin pigmentation is not affected by age and sex. The skin colour can be used as a predictor to know the intensity of melanin pigmentation in both anteriors and posteriors.

Introduction

The colour of the human gingiva is frequently described as “coral pink”. However, it varies from pale pink to bluish purple and is dependent upon the thickness of epithelium, the degree of keratinization, the magnitude of pigmentation, and the underlying vascularization.[1] Brownish or black pigmentation is often seen in human gingiva and has been reported in several countries. It can be present in both anterior and posterior regions. These blackish pigmentations in human gingiva is derived from the melanin granules. They are produced in melanosomes of melanocytes present in the epithelium commonly referred to as melanin pigmentation.[2]

Different patterns of melanin pigmentation can be observed. The prevalence rate of gingival pigmentation is diverse according to the race and country. The aetiology of the pigmentation being unclear, it is believed that genetics may be a background factor.[3] Several factors such as amalgam restoration adjacent to gingiva, melanoma, and long-term usage of antimalarial drugs and minocycline are potential confounders.[45]

Melanin is a non-haemoglobin derived pigment. Although it is claimed to occur as early as 3 hours after birth, it is generally prominent only in adults.[6] A study conducted with regard to the intensity of melanin pigmentation and age groups in Indian population has shown an increase in the intensity of gingival melanin pigmentation with increase in the age.[7] At the same time, there are no studies in the literature that have studied the association of the distribution of gingival melanin pigmentation with the age and sex in children of Tamil Nadu. Thus, it is the first of its kind that has studied the distribution of melanin pigmentation in the children between the ages of 1-12.

Also, it was found that the distribution of gingival melanin pigmentation varies with the skin colour.[8] Indian population have a dramatic variation in skin tones ranging from fair to dark can have a varied melanin distribution in the gingiva too. Though a study conducted among the South Indians has shown mild gingival pigmentation in fair skinned people and heavy pigmentation in dark skin people, there are no other supporting evidences in the literature with regard to the same.[9]

The intensity of gingival melanin pigmentation is another factor to be considered in terms of the aesthetics. Accurate tooth colour selection is of paramount importance in rendering aesthetic dental therapy to patients. While advances in “white aesthetics” for teeth are evident, the development of gingival “pink aesthetics” lags behind.[3] Therefore, understanding of pink aesthetics is critical because it will allow clinicians to better match the gingival portion of the dental prostheses to the soft tissues. It is therefore important to consider the variations seen in the intensity of gingival melanin pigmentation in the anterior and posterior regions.

Hence, the present study was conducted to observe the association between the age, sex and skin colour to the distribution and intensity of melanin pigmentation in the anterior and posterior region.

Methods

A cross-sectional, observational study was conducted in the Department of Pediatric and Preventive dentistry at the institute. Ethical clearance was obtained from the Institutional Review Board prior to the start of the study. The participants for the study were selected from the outpatients during the period from December 2018 to January 2019. A convenient sample of 100 children were selected between the age group of 1-12. The inclusion criteria comprised of participants with healthy gingiva. Any child with gingivitis, periodontitis or with any other systemic diseases which might induce colour changes in the gingiva were excluded. At the same time, participants with drug or chemical pigmentation on the gingiva, amalgam restorations, children on anti-malarial medication in the past, chemical skin peeling, albinism and the patients who had undergone any dental treatment in the past 6 months to 1 year were excluded from the study as well. The study was carried out under the informed consent of the parents or the caretakers.

The demographic details were recorded which included the age and sex of the child. The skin colour of the child was recorded under natural light with eyes as suggested by Wright.[10] Skin colour was classified by comparing the colour of the inner aspect of the upper arm, which is relatively unexposed to sunlight, and was graded as fair, wheatish, brown and dark.

The melanin distribution (anterior and posterior gingiva) and intensity of melanin pigmentation was recorded according to the classification given by Ponnaiyan et al., who used it for the South Indian population.[9] The classification is depicted in Table 1.

Table 1

Classification of melanin pigmentation distribution in the gingiva

Classes	Melanin distribution
1	Pigmentation in the attached gingiva only
2	Pigmentation in the attached and interdental papilla
3	Diffuse pigmentation involving all parts of the gingiva
4	Pigmentation in marginal gingival only
5	Pigmentation in interdental papilla only
6	Pigmentation in marginal and interdental gingiva.

The data collected was analyzed using SPSS software. The association between the various parameters were verified using Chi square test. P value less that 0.05 was considered to be statistically significant.

Results

In the present study, the participants were categorised into different age groups, gender and according to the variations in their colour. It was found that there was no statistically significant difference noted between the distribution of melanin pigmentation with the age (P = 0.457), sex (P = 0.673) and skin colour (P = 0.148) [Table 2].

Table 2

Association between the Age, sex and skin colour of the respondents to their

Age		Melanin Distribution				Total	P
		Anteriors	Posteriors	Both	None
1-3 years	Count	0	0	13	0	13	0.457
	%	0.0%	0.0%	100.0%	0.0%	100.0%
4-6 years	Count	1	0	17	0	18
	%	5.6%	0.0%	94.4%	0.0%	100.0%
7-9 years	Count	0	0	35	4	39
	%	0.0%	0.0%	89.7%	10.3%	100.0%
10-12 years	Count	1	1	27	1	30
	%	3.3%	3.3%	90.0%	3.3%	100.0%
Total	Count	2	1	92	5	100
	%	2.0%	1.0%	92.0%	5.0%	100.0%
Sex		Melanin distribution
		Anteriors	Posteriors	Both	None	Total
Male	Count	1	1	42	3	47	0.673
	%	2.1%	2.1%	89.4%	6.4%	100.0%
Female	Count	1	0	50	2	53
	%	1.9%	0.0%	94.3%	3.8%	100.0%
Total	Count	2	1	92	5	100
	%	2.0%	1.0%	92.0%	5.0%	100.0%
Skin colour		Melanin distribution
		Anteriors	Posteriors	Both	None	Total
Fair	Count	1	0	21	4	26	0.148
	%	3.8%	0.0%	80.8%	15.4%	100.0%
Wheatish	Count	1	0	24	1	26
	%	3.8%	0.0%	92.3%	3.8%	100.0%
Brown	Count	0	0	22	0	22
	%	0.0%	0.0%	100.0%	0.0%	100.0%
Dark	Count	0	1	25	0	26
	%	0.0%	3.8%	96.2%	0.0%	100.0%
Total	Count	2	1	92	5	100
	%	2.0%	1.0%	92.0%	5.0%	100.0%

Source : computed data

A statistically significant association was noted between the skin colour and the intensity of melanin pigmentation in both anterior and posterior gingiva (P = 0.000). In fair and wheatish-skinned individuals the pigmentation was noted only in the attached gingiva. Whereas, in brown and dark individuals, diffuse melanin pigmentation involving all parts of the gingiva was noted [Table 3].

Table 3

Association between the Age, sex and skin colour of the respondents to their Anterior Intensity

Age		Anterior Intensity								P
		Class 0	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6	Total
1-3 years	Count	0	4	1	3	4	0	1	13	0.248
	%	0.0%	30.8%	7.7%	23.1%	30.8%	0.0%	7.7%	100.0%
4-6 years	Count	0	1	3	5	3	0	6	18
	%	0.0%	5.6%	16.7%	27.8%	16.7%	0.0%	33.3%	100.0%
7-9 years	Count	4	13	4	9	5	1	3	39
	%	10.3%	33.3%	10.3%	23.1%	12.8%	2.6%	7.7%	100.0%
10-12 years	Count	1	7	3	8	3	3	5	30
	%	3.3%	23.3%	10.0%	26.7%	10.0%	10.0%	16.7%	100.0%
Total	Count	5	25	11	25	15	4	15	100
	%	5.0%	25.0%	11.0%	25.0%	15.0%	4.0%	15.0%	100.0%
Sex		Anterior Intensity
		Class 0	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6	Total
Male	Count	3	13	4	15	6	1	5	47	0.546
	%	6.4%	27.7%	8.5%	31.9%	12.8%	2.1%	10.6%	100.0%
Female	Count	2	12	7	10	9	3	10	53
	%	3.8%	22.6%	13.2%	18.9%	17.0%	5.7%	18.9%	100.0%
Total	Count	5	25	11	25	15	4	15	100
	%	5.0%	25.0%	11.0%	25.0%	15.0%	4.0%	15.0%	100.0%
Skin Colour		Anterior Intensity
		Class 0	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6	Total
Fair	Count	4	11	0	0	7	3	1	26	0.000*
	%	15.4%	42.3%	0.0%	0.0%	26.9%	11.5%	3.8%	100.0%
Wheatish	Count	1	13	2	1	7	1	1	26
	%	3.8%	50.0%	7.7%	3.8%	26.9%	3.8%	3.8%	100.0%
Brown	Count	0	1	1	14	0	0	6	22
	%	0.0%	4.5%	4.5%	63.6%	0.0%	0.0%	27.3%	100.0%
Dark	Count	0	0	8	10	1	0	7	26
	%	0.0%	0.0%	30.8%	38.5%	3.8%	0.0%	26.9%	100.0%
Total	Count	5	25	11	25	15	4	15	100
	%	5.0%	25.0%	11.0%	25.0%	15.0%	4.0%	15.0%	100.0%

Source : computed data

In the posterior region, the melanin pigmentation was noticed only in the interdental papilla in fair skinned individuals, and only in marginal gingiva in wheatish skinned individuals. On the other hand, a diffuse pigmentation involving all parts of the gingiva was noticed in brown and dark skinned individuals [Table 4].

Table 4

Association between the Age, sex and skin colour of the respondents to their Posterior Intensity

Age		Posterior Intensity							Total	P
		Class 0	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6
1-3 years	Count	0	2	4	0	2	4	1	13	0.270
	%	0.0%	15.4%	30.8%	0.0%	15.4%	30.8%	7.7%	100.0%
4-6 years	Count	0	0	5	6	3	2	2	18
	%	0.0%	0.0%	27.8%	33.3%	16.7%	11.1%	11.1%	100.0%
7-9 years	Count	4	3	8	3	8	8	5	39
	%	10.3%	7.7%	20.5%	7.7%	20.5%	20.5%	12.8%	100.0%
10-12 years	Count	2	1	11	3	7	5	1	30
	%	6.7%	3.3%	36.7%	10.0%	23.3%	16.7%	3.3%	100.0%
Total	Count	6	6	28	12	20	19	9	100
	%	6.0%	6.0%	28.0%	12.0%	20.0%	19.0%	9.0%	100.0%
Sex		Posterior Intensity
		Class 0	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6	Total
Male	Count	3	3	14	5	10	9	3	47	0.984
	%	6.4%	6.4%	29.8%	10.6%	21.3%	19.1%	6.4%	100.0%
Female	Count	3	3	14	7	10	10	6	53
	%	5.7%	5.7%	26.4%	13.2%	18.9%	18.9%	11.3%	100.0%
Total	Count	6	6	28	12	20	19	9	100
	%	6.0%	6.0%	28.0%	12.0%	20.0%	19.0%	9.0%	100.0%
Skin Colour		Posterior Intensity
		Class 0	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6	Total
Fair	Count	5	2	0	0	8	11	0	26	0.000*
	%	19.2%	7.7%	0.0%	0.0%	30.8%	42.3%	0.0%	100.0%
Wheatish	Count	1	1	3	1	12	8	0	26
	%	3.8%	3.8%	11.5%	3.8%	46.2%	30.8%	0.0%	100.0%
Brown	Count	0	0	14	4	0	0	4	22
	%	0.0%	0.0%	63.6%	18.2%	0.0%	0.0%	18.2%	100.0%
Dark	Count	0	3	11	7	0	0	5	26
	%	0.0%	11.5%	42.3%	26.9%	0.0%	0.0%	19.2%	100.0%
Total	Count	6	6	28	12	20	19	9	100
	%	6.0%	6.0%	28.0%	12.0%	20.0%	19.0%	9.0%	100.0%

Source: computed data

Discussion

Gingival pigmentation is transmitted genetically in certain populations and hence it is appropriate to call this pigmentation as physiologic or racial gingival pigmentation.[11] Melanocytes normally occur in the gingiva of all humans.[12] Melanin, a non-haemoglobin derived pigment, is formed by the cells called melanocytes, which are dendritic cells of neuroectodermal origin in basal and spinous layers of gingival epithelium. These melanin pigmented areas are present only when melanin granules are synthesized to melanocytes and transferred to the keratinocytes, on exposure to friction or ultraviolet light.[13]

In the present study, no association was observed between the age, the distribution and intensity of melanin pigmentation, which is in contradiction to the study conducted by Jainanai et al., who observed an increase in the distribution and intensity of melanin pigmentation with age in the Indian population.[7] However, in the same study, the results have shown that there is no gingival melanin pigmentation noticed in the posterior gingiva below 12 years of age. This has in turn been attributed to decreased melanogenesis in the mixed dentition.[7]

The possible reason for the difference in the results could be attributed to the age group involved in the later study, where individuals up to 20 years were involved, whereas, in the present study, only children upto 12 years were included. The melanin content in children is comparatively lesser than the adults due to smaller corneocytes, keratinocytes and thinner epidermis. At the same time, there is an increase in the water content in the stratum corneum that reduces the need for the keratinocytes to produce melanin pigments.[1415]

In the present study, it was noted that the distribution and intensity of melanin pigmentation in both anterior and posterior regions did not differ between the sexes. The results of the present study is similar to the previous study done in adults.[9]

In the present study, an attempt was made to assess the correlation of the skin colour with the distribution and intensity of gingival melanin pigmentation, owing to the fact that darker skin coloured individuals tend to have more melanin content and hence more oral pigmentation and the vice versa in fair-skinned individuals. Though the skin colour did not have a statistically significant association with the distribution of melanin pigmentation, a statistically significant association was noted between the intensity of melanin pigmentation in the anterior and posterior region in the current study.

The results of this study showed that in fair and wheatish skinned individuals, the pigmentation was noted only in the attached gingiva in the anterior region. In the posterior region, it was noticed only in the interdental papilla in fair skinned individuals, and only in marginal gingiva in wheatish skinned individuals. Whereas in brown and dark individuals, diffuse melanin pigmentation involving all parts of the gingiva was noted both in the anterior and posterior regions. However, in the previous studies, the pigmentation of gingiva had a varied distribution. A study conducted on the South Indians showed a majority of pigmentation in the attached gingiva and interdental papilla which is similar to the results of the present study.[9] However, in the previous study, the association of the melanin pigmentation with respect to the different skin colours were not studied.[9]

Another study conducted by Jainani et al. has shown that brown and dark-skinned individuals had more gingival melanin pigmentation in attached gingiva and interdental papilla, which is in contradiction to the present study where diffuse gingival melanin pigmentation was noticed in the anterior and posterior regions.[7] Whereas in the fair and wheatish skinned individuals, the pigmentation was noticed either only in the interdental papilla, marginal gingiva or attached gingiva in the study conducted by Jainani et al., which is similar to the results of the present study.[7]

Identifying gingival pigmentation at an earlier stage is important because early surgical intervention may improve the aesthetic appearance and delay the reappearance.[16171819] However, the same study should be conducted with a larger sample size in order to arrive at definite conclusions.

Conclusion

Knowing about the gingival pigmentation is not only important for understanding the “pink aesthetics” but also in preventing a psychological negativity in children. With the findings of the present study, it can be concluded that:

The distribution of melanin pigmentation is not affected by age, sex and skin colour

The intensity of melanin pigmentation is not affected by age and sex

Skin colour can be used as a predictor to know the intensity of melanin pigmentation in both the anterior and posterior regions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.