- Email: [email protected]
The relationship between physiologic pigmentation of the skin and oral mucosa in Yemenite Jews
The relationship hysiologic pigmentation of the skin and oral mucosa in Yemenite Jews Xhulamit HEBREW
Steigmanx, LlNI~j~RSITY-H,1DdSSAH
D.X.D.,
fevusulem, SCHOOL
Iwael OF
DESTISTRY
he skin and oral mucosa are the only two tissues which easily show eolo~ changes. It was once thought that tissue pigmentation was immutable; thereSore, it served as a basis for ethnic determination. Any alteration of pigment, especially in the oral mucosa, served as a diagnostic sign in stating systemic pathologic changes. Today we know that there are many variations in skin color among members of the same ethnic group and also that changes in the pigmentation of oral mucosa are not always pathologic signs, but may be normal physiologic manifestations. Edwards and Duntley6 examined skin color spectrophotometrically and found that the color is defined by five primary pigments-melanin, melanoid, oxyhemoglobin, reduced hemoglobin, and carotene. Melanin. Granules of this pigment are produced and stored in large dendrified cells known as melanodendrocytes which lie in the basal layer of the epidermis, especially along the rete pegs. 2 Melanin production is mostly hereditary, and pigmentation is determined by a number of genes which are responsible for the quantity and distribubion of the pigment granules.7 A secondary factor in melanin production depends on the penetration of sun rays through the skin and on the individual ability of skin cells to react to the stimulation of these rays. Melanin imparts shades of yellow, brown, and black to the skin. MeZanoid. Granules of this pigment, are sca.ttered in the stratum lucidum and stratum corneum of the skin. Initially, it was assumed tha.t melanoid was a degradation product of melanin, but more recently it has been shown that such a relationship is highly improbab1e.l’ nlelanoid imparts, a clear yellow shade to the skin. Oxyhemoglobin and reduced hemoglobin. The skin color is affected by the capillary and venous plexuses shining through the skin. 32
Volume Number
Physiologic
19 1
pigmentation
of skin and
ornl
mucosa
33
Carotene. This pigment is distributed in the lipids of the st,ratum corneum and stratum lucidum and gives a deep yellow color to the skin. It is found in higher concentrations in women than in men. The differences in amount and distribution of these pigments account for the variations in skin color between the sexes and between different parts of the body. In examinations of persons of various ra,ces, it has been found that color differences between races are based only on the production of various amounts of primary ectodermal melanin and mela.noid, the amount of all other pigments being the same in all races6 The first studies in the field of physiologic pigment formation in oral tissues were made by Ramel and Adachi,l who found dendrite cells containing pigment in the mucosa of the lower lip in white females. This was more pronounced in brunettes than in blondes. In 1927 Becker2 examined fifty-three persons, and in 74 per cent of them he found, with the help of the dopa reaction, the presence of melanodendrocytes with branched and intervening dendrites in the oral mucosa, although on clinical examination no pigment was visible. He also found a large number of chromatophores (pigment-ca,rrying cells) in the underlying connective tissue. Cahn* made clinical examinations of Negroes, Latin Americans, and Hindus. In many of them he found clinically visible pigmentation of oral mucosa, although there were no pathologic involvements-either systemic or local. Laidlaw,s in 1932, made histologic slides of the oral mucosa of Negroes and Caucasians without clinically visible oral pigmentation. By means of the dopa reaction, he discovered melanodendrocytes and pigment granules in the basal layer of the mucosa. He came to the conclusion that melanodendrocytes are a constant and normal attribute of mucous membranes and that the oral mucosa has the potential to produce pigment. Studies on Romanians and Gypsies were carried out by Prinzll in 1932, and Negroes were studied by Monashl” in 1932 and by Dummett? ij in 1945 and 1946. These studies showed a positive correlation between oral and cutaneous pigmentation. On t,he other hand, oral pigmentation was lacking in a sufficiently large number of dark-skinned Negroes to make the constancy of such an association questionable.4 Lately, great interest has been shown in the question of oral pigmentation, as witnessed ‘by the Symposium on Oral Pigmentation held in Tuskegee, Slabama, in November, 1959. The object of the present investigation was to determine whether or not there is a positive correlation between physiologic pigmentation of oral mucosa and various shades of skin in Yemenite Jews.” MATERIALS
AND
METHODS
Two hundred and one Jewish children of Yemenite origin were examined. In the families from which these children came there had been no known inter“Yemenite Jews left Israel around 900 B.C. for the communities and lived until establishment of the state Jewish Yemenite population i&migrated to Israel.
Yemen, where they of Israel. At that
settled in time the
closed entire
cm., 0.x. & OP. January,
1965
marriage with other ethnic groups for many generations. It was t,herefore assumed that no extraneous hereditary factors, with respect to pigmentation, had influenced the group examined. A11 the children were healthy, and none of them were taking any medicine. The age range was from 6 to 11 years. There were 98 girls and 103 boys. The gingivae, buceal mucosa, lips, tongue, floor of the mouth, and hard and soft palate were checked clinically for amount and distribution of pigment. The shade of pigment was classified as very dark brown to black, brown, light brown-yellow. The skin of the sacral region, known for minimal secondary production of pigment (due to lack of sun-ray stimulation) served as a basis of defining skin color. Skin color was classified as dark brown, light brown, and yellowish white. The collected material was submitted to statistical analysis in which the ehi-squa,re test was used. FINDINGS
Among 145 children with dark brown skin, 109 had oral pigmentation of various intensity. Of the 56 children with light brown skin, 29 showed oral pigmentation. No children with yellowish white skin were found in the sample examined. Table 1. Presence of pigment 1 Dark brown skirt 1 No. 1 Pey cent Presence Absence
of pigment of pigment
109 36
Total
145
/
Li,clh.t brown
skin
1
1
No.
cent
1
75.16 24.82
29 27
100.00
56
1 Per
51.76 48.19 100.00
No.
Total j Per cent
138 63
68.65 31.34
SE
100.00
As shown in Table I, the relation between the presence of pigment in the oral cavity and skin color \t:as proved beyond any doubt to bc statistically significant: x2 (1) = 10.25 P < 0.01 The relationship between the intensity of melanin pigmentation in tile oral. ca,vity and the skin (Table II) was statistically significant : x2 (1) = 5.21 P < 0.05 Table
Intensity
il. Relationship of the intensity of
pigment
Black-brown and brown pigment Brown-yellow pigment Total
/
Dark No. 56
5.3 109
skin. / Per cent
brown
of oral and cutaneous pigmentation Light No.
brown ski?% 1 Per cent
51.2 48.8
8 21
27.6 72.4
100.0
29
100.0
Total No. 64 74 __138
/
Per
cent 46.4 53.6
100.0
Volume Number
19 1
Physiologic
Table
III. Relationship
between
1 Black-brown 1 BoG;;;;ant
pigmentation
of skin
sex and intensity
1 ,Elent
and ornl mucosa
35
of oral pigmentation
) ;%zt
j NT:y=L,
1 No.
T$
cent
Sex
Female Male
9
42.85 57.14
12
Total
-ii-
25 18
loo.oo43--
58.12 41.85
35 39
100.00
74
47.28 52.68 ___ 100.00
-
29 34
-
46.02 53.95
98 103 ___ 201
100.00
63
48.75 51.24 100.00
As shown in Table III, there were no significant differences in oral pigmentation between males and females. The numbers given in Table IV are of no statistical significance, but they indicate that, with increase in age, there is a gradual decrease in the percentage of brown-yellow pigment and an increase in the percentage of brown and blackbrown pigment. Table V refers to the pigment distribution in the oral cavity as found in the pooled sample. With reference to the skin color groups, it was found that the various shades of pigment appeared in different locations and showed dissimilar configurations, as follows : Children with dark brown skin. In children with bla.ck-brown oral pigmentation the pigment covered all the gingiva except the interdental Table
IV.
Relationship between age and intensity of oral pigmentation Black-brown pigment NO.
Age
6 to 8 to 10 +
7
10
9
8 __ 3
Total
Table
78 9
10 11 12 13
14
No.
16.66 ___
19 17 __ 7
26.76 34.69 __38.88
42 24 __ 8
15.21
43
31.15
74
Lower labial Upper labial Soft palate Upper buccal Lower buccal Buccal mucosa
Total
1 Per
-
cent
No.
)
71
59.15 48.97 44.44
__
53.62
Percent 100.00 100.00 100.00 ____-
49 18
138
100.00
of pigmentation in the oral cavity
Loca,tion
NO. 2 3 4 5 6
( Per cent
14.08 16.32
Distribution
pigment
No.
Percent
21
V.
1
/
Brown-yellow
Brown, pigment
gingivae gingivae gingivae gingivae opposite
Posterior mucosa part ofopposite hard Buccal Lower posterior lingual Lower anterior lingual Anterior part of hard Labial mucosa Tongue Sublingual area
B1W.k brown
Brown
I pigmi3n.t
I pigment
pigment
No.
( Per cent
33 28 4
91
30.4 20.0 17.0 13.0
11
3.7 ;.i 1:3
18
Brown-
Total
yellow
teeth
1
3
40 21 46 12 2 7
palate lower teeth gingivae gingivae palate
-1 -
2
5
8
1
i
.I
2
2
-
1 -
1 -
-
-
-
10 1 1; upper
Ti
59 50 E
10.0
0.7 0.3
-
36
SteignlclnlL
as., 9.x. & 0.P. Januaryr1965
papillae; it was composed of very dark oval or irregular splashes, joined by lighter, diffuse, sandlike pigment. The pigment was most intense in the labial parts of the gingivae and less intense in the buccal parts, hard palate, and buccal mucosa. In children with brown oral pigmentation the pigment was arranged in the form of stains 2 to 4 mm. in diameter, mostly around the border of the attached labial gingivae. In children with light brown-yellow pigment there was a diffuse pigmentation of labial gingirae and soft palate, including the uvula. In all cases the pigmentation in the oral cavity was symmetrically distributed. Children with light brown skin. In these casesthere was diffuse pigmentation in the labial gingirae, mostly of light brown color, found especially in the area of the canines. There was no pigmentation in other parts of the oral cavity, except in the soft palate. DISCUSSION The correlation of pigmentation of extra- and intraoral tissues has long attracted various researchers, but no definite conclusion was reached. This study, carried out on members of a, closed ethnic group with relatively dark skin as one of its characteristics, has statistically proved beyond doubt the relationship between cutaneous and oral pigmentation (Table I). This is to say t,hat in dark-skinned people, or those belonging to an ethnic group in which dark skin is characteristic, it would be reasonable to expect the appearance of a normal physiologic intraoral pigmenta,tion. Another point of interest was the intensity of oral pigmentation and its relationship to skin color. Nonash,lO in his examination of 220 Keg-roes, had observed that in light-skinned Negroes a fair pigment was present in irregular splashes, found mostly around the border of the attached gingiva. Negroes of a brown complexion showed a darker pigmentation passing ribbonlike along the gingivae. In very dark Negroes all the gingiva was covered with dark pigment,. L>nmmett5 examined 636 Negroes and discovered that in many of them the gingival pigmentation was directly proportional to skin pigmentation. The present study has proved statistically that the intensity of oral pigmentation is directly proportional to the intensity of skin color (Ta.ble II). Volker12 says that the variations in skin color are caused by the rate and amount of melanin production by melanocytcs rather than by the number of mclanocytes present. It was noted in the present survey, however, that the light oral pigment appeared a,s a diffuse, sandlike pigmentation whereas the dark one formed large irregular stains. It remains to be determined by means of histologic studies whether there is a correlation between the intensity of pigment and the prevalence of pigment cells in cases of oral pigmentation. There is some controversary about the relationship between age and oral pigmentation. MonashlO has found very light pigmentation in infants which, with t.ime, grew in intensity and was almost completed by the age of 10 years. On the other hand, Prinzll stated that physiologic pigmentation does not appear
Volume 19 Number 1
Physiologic pigmentation
of skin
and
oral
mz~cosa
37
in children and is clinically visible only after puberty. In Letters to the Editor, published in the Journal of the American Medical Association in 1958, there is found a statement that “the physiological pigmentation usually develops fully during the second decade” of life.g The present study involved children 6 to 11 years of age. This, in itself, shows that all kinds of oral pigmentations appear in young children. The number of children in each age group was too small to permit a definite conclusion based on statistical values, but a trend was found which indicated that the intensity of pigmentation increases with age (Table IV). As in all previous works, it was found that in persons with oral pigmcntation the prevalent site of its appearance is the labial gingiva. It is not quite clear as yet whether this pigmentation is an expression of heredity or whether secondary environmental inflaences, such as stimulation by sunshine, dust particles, etc., upon this region are superimposed upon the hereditary etiology of oral pigmentation in dark-skinned persons. Since the location of labial pigment.ation might be subject to environmental influences, conclusions concerning hereditary trends of pigmentat,ion should be evaluated in regions of the oral cavity not exposed to such influences (for example, the buccal gingiva, the hard and soft palate, and the tongue). MonashlO found that the distribution of pigment, in descending order of frequency, was as follows: buccal gingiva, ha.rd palate, tongue, lips, and soft palate. Dummett” reported the distribution as follows: gingivae 67 per cent; hard palate, 61 per cent; buccal mucosa, 22 per cent; and tongue, 15 per cent. Both studies were carried out on Negroes, and the distribut,ion of pigment was very similar in both cases. In the present study no children were found with pigmentation on the tongue or lips, and only 2.6 per cent of the children examined had pigmentation of the hard palate. The distribution was as follows: labial gingivae, 50.4 per cent; buccal gingivae, 23 per cent; soft palate, 17 per cent; buccal mucosa 6.4 per cent (Table V). This finding is in contradistinction to’ the distribution of oral pigmentation reported in Negroes and leads to the thought that oral pigmentation in dark-skinned persons ma,y be dominated by genetic factors which vary in different ethnic groups. Further studies may be useful to verify this finding which, if found positive, could serve as a diagnostic aid in determination of ethnic origin. SUMMARY
Clinical examinations of 201 Jewish Yemenite children were carried out in order to determine the relationship between oral and cut.aneous pigmentation, The findings were as follows: 1. A correlation between oral and cutaneous pigmentation was proved statistically beyond doubt. 2. A relationship between the intensity of oral pigmentation and skin color was statistically established. 3. The incidence of pigmentation did not differ between the sexes. 4. The intensity of pigmentation seemed to increase with age.
O.S., O.&r. & 0.P. January,
5. There was a ccrt,ain to children of this ethnic distribution in Negroes. I wish to thank Dr. this study was conducted, in charge of orthodontics paper.
1965
pattern oi’ oral pigment. distributkn specific and different from patterns of pigment
group
J. Springer, Instructor in the Dental School, Jerusalem, at the time for arousing my interest in the subject and Dr. E. Koyomdjiski, a,t the Dental School, Jerusalem, for her help in the writing of this
REFERENCES
1. Adaehi, B.: Das Hautpigment beim Menschen und bei den Affen, Ztschr. Morphul. u. Anthropol. 6: 1, 1903 (Cited by Beekerz). 2. Becker, S. W.: Melanin Pigmentation, Arch. Dermat. & Syph. 16: 269-290, 1927. 3. Dummett. C. 0.: Clinical Observahions on Pigment Variations in Healthv Oral Tissues of the Negrb, J. D. Res. 24: 7-13, 1945. 4. Dummett, C. 0.: The Relationship Between Physiologic Pigmentation in the Oral and Cutaneous Tissues of the Negro. J. D. R’es. 25: X5-156, 1946. 5. Dummett, C. 0.: Physiologig pigmentation of the Oral and Cutaneous Tissues in the Negro, J. D. Res. 25: 421-432. 1946. 6. Edwards, E., and Duntley, Q.: The Pigments and Colour of Living Human Skin, Am. J. Anat. 65: l-33, 1939. 7. Kenney, J. A., Jr., and Curtis, A. C.: The Physiology of Pigmentation, 0x-U.. SURG., ORAL MED.
& ORAL
PATH.
7:
241-254,
1954.
8. Laidlaw, G. F., and Cal+, L. R.: Melanoblasts in the Gum, J. D. Res. 9. Letters to the Editor: Pigmentation of the Gums, J. A. M. A. 168: 10. Monash, 8.: Normal Pigmentation of the Oral Mucosae, Arch. Derm. & 1932. 11. Prinz, H.: Pigmentation of the Oral Mucous Membrane, Dental Cosmos. and Biochemistry 12. Volker, J. F., and Kenney, J. A., Jr.: The Physiology J. Periodont. 31: 346-355, 3960.
12: 534-537, 1932. 1296, 1958. Syph. 26: 139-147, 74: 554-561, 1932. of Pigmentation,
Steigmanx, LlNI~j~RSITY-H,1DdSSAH
D.X.D.,
fevusulem, SCHOOL
Iwael OF
DESTISTRY
he skin and oral mucosa are the only two tissues which easily show eolo~ changes. It was once thought that tissue pigmentation was immutable; thereSore, it served as a basis for ethnic determination. Any alteration of pigment, especially in the oral mucosa, served as a diagnostic sign in stating systemic pathologic changes. Today we know that there are many variations in skin color among members of the same ethnic group and also that changes in the pigmentation of oral mucosa are not always pathologic signs, but may be normal physiologic manifestations. Edwards and Duntley6 examined skin color spectrophotometrically and found that the color is defined by five primary pigments-melanin, melanoid, oxyhemoglobin, reduced hemoglobin, and carotene. Melanin. Granules of this pigment are produced and stored in large dendrified cells known as melanodendrocytes which lie in the basal layer of the epidermis, especially along the rete pegs. 2 Melanin production is mostly hereditary, and pigmentation is determined by a number of genes which are responsible for the quantity and distribubion of the pigment granules.7 A secondary factor in melanin production depends on the penetration of sun rays through the skin and on the individual ability of skin cells to react to the stimulation of these rays. Melanin imparts shades of yellow, brown, and black to the skin. MeZanoid. Granules of this pigment, are sca.ttered in the stratum lucidum and stratum corneum of the skin. Initially, it was assumed tha.t melanoid was a degradation product of melanin, but more recently it has been shown that such a relationship is highly improbab1e.l’ nlelanoid imparts, a clear yellow shade to the skin. Oxyhemoglobin and reduced hemoglobin. The skin color is affected by the capillary and venous plexuses shining through the skin. 32
Volume Number
Physiologic
19 1
pigmentation
of skin and
ornl
mucosa
33
Carotene. This pigment is distributed in the lipids of the st,ratum corneum and stratum lucidum and gives a deep yellow color to the skin. It is found in higher concentrations in women than in men. The differences in amount and distribution of these pigments account for the variations in skin color between the sexes and between different parts of the body. In examinations of persons of various ra,ces, it has been found that color differences between races are based only on the production of various amounts of primary ectodermal melanin and mela.noid, the amount of all other pigments being the same in all races6 The first studies in the field of physiologic pigment formation in oral tissues were made by Ramel and Adachi,l who found dendrite cells containing pigment in the mucosa of the lower lip in white females. This was more pronounced in brunettes than in blondes. In 1927 Becker2 examined fifty-three persons, and in 74 per cent of them he found, with the help of the dopa reaction, the presence of melanodendrocytes with branched and intervening dendrites in the oral mucosa, although on clinical examination no pigment was visible. He also found a large number of chromatophores (pigment-ca,rrying cells) in the underlying connective tissue. Cahn* made clinical examinations of Negroes, Latin Americans, and Hindus. In many of them he found clinically visible pigmentation of oral mucosa, although there were no pathologic involvements-either systemic or local. Laidlaw,s in 1932, made histologic slides of the oral mucosa of Negroes and Caucasians without clinically visible oral pigmentation. By means of the dopa reaction, he discovered melanodendrocytes and pigment granules in the basal layer of the mucosa. He came to the conclusion that melanodendrocytes are a constant and normal attribute of mucous membranes and that the oral mucosa has the potential to produce pigment. Studies on Romanians and Gypsies were carried out by Prinzll in 1932, and Negroes were studied by Monashl” in 1932 and by Dummett? ij in 1945 and 1946. These studies showed a positive correlation between oral and cutaneous pigmentation. On t,he other hand, oral pigmentation was lacking in a sufficiently large number of dark-skinned Negroes to make the constancy of such an association questionable.4 Lately, great interest has been shown in the question of oral pigmentation, as witnessed ‘by the Symposium on Oral Pigmentation held in Tuskegee, Slabama, in November, 1959. The object of the present investigation was to determine whether or not there is a positive correlation between physiologic pigmentation of oral mucosa and various shades of skin in Yemenite Jews.” MATERIALS
AND
METHODS
Two hundred and one Jewish children of Yemenite origin were examined. In the families from which these children came there had been no known inter“Yemenite Jews left Israel around 900 B.C. for the communities and lived until establishment of the state Jewish Yemenite population i&migrated to Israel.
Yemen, where they of Israel. At that
settled in time the
closed entire
cm., 0.x. & OP. January,
1965
marriage with other ethnic groups for many generations. It was t,herefore assumed that no extraneous hereditary factors, with respect to pigmentation, had influenced the group examined. A11 the children were healthy, and none of them were taking any medicine. The age range was from 6 to 11 years. There were 98 girls and 103 boys. The gingivae, buceal mucosa, lips, tongue, floor of the mouth, and hard and soft palate were checked clinically for amount and distribution of pigment. The shade of pigment was classified as very dark brown to black, brown, light brown-yellow. The skin of the sacral region, known for minimal secondary production of pigment (due to lack of sun-ray stimulation) served as a basis of defining skin color. Skin color was classified as dark brown, light brown, and yellowish white. The collected material was submitted to statistical analysis in which the ehi-squa,re test was used. FINDINGS
Among 145 children with dark brown skin, 109 had oral pigmentation of various intensity. Of the 56 children with light brown skin, 29 showed oral pigmentation. No children with yellowish white skin were found in the sample examined. Table 1. Presence of pigment 1 Dark brown skirt 1 No. 1 Pey cent Presence Absence
of pigment of pigment
109 36
Total
145
/
Li,clh.t brown
skin
1
1
No.
cent
1
75.16 24.82
29 27
100.00
56
1 Per
51.76 48.19 100.00
No.
Total j Per cent
138 63
68.65 31.34
SE
100.00
As shown in Table I, the relation between the presence of pigment in the oral cavity and skin color \t:as proved beyond any doubt to bc statistically significant: x2 (1) = 10.25 P < 0.01 The relationship between the intensity of melanin pigmentation in tile oral. ca,vity and the skin (Table II) was statistically significant : x2 (1) = 5.21 P < 0.05 Table
Intensity
il. Relationship of the intensity of
pigment
Black-brown and brown pigment Brown-yellow pigment Total
/
Dark No. 56
5.3 109
skin. / Per cent
brown
of oral and cutaneous pigmentation Light No.
brown ski?% 1 Per cent
51.2 48.8
8 21
27.6 72.4
100.0
29
100.0
Total No. 64 74 __138
/
Per
cent 46.4 53.6
100.0
Volume Number
19 1
Physiologic
Table
III. Relationship
between
1 Black-brown 1 BoG;;;;ant
pigmentation
of skin
sex and intensity
1 ,Elent
and ornl mucosa
35
of oral pigmentation
) ;%zt
j NT:y=L,
1 No.
T$
cent
Sex
Female Male
9
42.85 57.14
12
Total
-ii-
25 18
loo.oo43--
58.12 41.85
35 39
100.00
74
47.28 52.68 ___ 100.00
-
29 34
-
46.02 53.95
98 103 ___ 201
100.00
63
48.75 51.24 100.00
As shown in Table III, there were no significant differences in oral pigmentation between males and females. The numbers given in Table IV are of no statistical significance, but they indicate that, with increase in age, there is a gradual decrease in the percentage of brown-yellow pigment and an increase in the percentage of brown and blackbrown pigment. Table V refers to the pigment distribution in the oral cavity as found in the pooled sample. With reference to the skin color groups, it was found that the various shades of pigment appeared in different locations and showed dissimilar configurations, as follows : Children with dark brown skin. In children with bla.ck-brown oral pigmentation the pigment covered all the gingiva except the interdental Table
IV.
Relationship between age and intensity of oral pigmentation Black-brown pigment NO.
Age
6 to 8 to 10 +
7
10
9
8 __ 3
Total
Table
78 9
10 11 12 13
14
No.
16.66 ___
19 17 __ 7
26.76 34.69 __38.88
42 24 __ 8
15.21
43
31.15
74
Lower labial Upper labial Soft palate Upper buccal Lower buccal Buccal mucosa
Total
1 Per
-
cent
No.
)
71
59.15 48.97 44.44
__
53.62
Percent 100.00 100.00 100.00 ____-
49 18
138
100.00
of pigmentation in the oral cavity
Loca,tion
NO. 2 3 4 5 6
( Per cent
14.08 16.32
Distribution
pigment
No.
Percent
21
V.
1
/
Brown-yellow
Brown, pigment
gingivae gingivae gingivae gingivae opposite
Posterior mucosa part ofopposite hard Buccal Lower posterior lingual Lower anterior lingual Anterior part of hard Labial mucosa Tongue Sublingual area
B1W.k brown
Brown
I pigmi3n.t
I pigment
pigment
No.
( Per cent
33 28 4
91
30.4 20.0 17.0 13.0
11
3.7 ;.i 1:3
18
Brown-
Total
yellow
teeth
1
3
40 21 46 12 2 7
palate lower teeth gingivae gingivae palate
-1 -
2
5
8
1
i
.I
2
2
-
1 -
1 -
-
-
-
10 1 1; upper
Ti
59 50 E
10.0
0.7 0.3
-
36
SteignlclnlL
as., 9.x. & 0.P. Januaryr1965
papillae; it was composed of very dark oval or irregular splashes, joined by lighter, diffuse, sandlike pigment. The pigment was most intense in the labial parts of the gingivae and less intense in the buccal parts, hard palate, and buccal mucosa. In children with brown oral pigmentation the pigment was arranged in the form of stains 2 to 4 mm. in diameter, mostly around the border of the attached labial gingivae. In children with light brown-yellow pigment there was a diffuse pigmentation of labial gingirae and soft palate, including the uvula. In all cases the pigmentation in the oral cavity was symmetrically distributed. Children with light brown skin. In these casesthere was diffuse pigmentation in the labial gingirae, mostly of light brown color, found especially in the area of the canines. There was no pigmentation in other parts of the oral cavity, except in the soft palate. DISCUSSION The correlation of pigmentation of extra- and intraoral tissues has long attracted various researchers, but no definite conclusion was reached. This study, carried out on members of a, closed ethnic group with relatively dark skin as one of its characteristics, has statistically proved beyond doubt the relationship between cutaneous and oral pigmentation (Table I). This is to say t,hat in dark-skinned people, or those belonging to an ethnic group in which dark skin is characteristic, it would be reasonable to expect the appearance of a normal physiologic intraoral pigmenta,tion. Another point of interest was the intensity of oral pigmentation and its relationship to skin color. Nonash,lO in his examination of 220 Keg-roes, had observed that in light-skinned Negroes a fair pigment was present in irregular splashes, found mostly around the border of the attached gingiva. Negroes of a brown complexion showed a darker pigmentation passing ribbonlike along the gingivae. In very dark Negroes all the gingiva was covered with dark pigment,. L>nmmett5 examined 636 Negroes and discovered that in many of them the gingival pigmentation was directly proportional to skin pigmentation. The present study has proved statistically that the intensity of oral pigmentation is directly proportional to the intensity of skin color (Ta.ble II). Volker12 says that the variations in skin color are caused by the rate and amount of melanin production by melanocytcs rather than by the number of mclanocytes present. It was noted in the present survey, however, that the light oral pigment appeared a,s a diffuse, sandlike pigmentation whereas the dark one formed large irregular stains. It remains to be determined by means of histologic studies whether there is a correlation between the intensity of pigment and the prevalence of pigment cells in cases of oral pigmentation. There is some controversary about the relationship between age and oral pigmentation. MonashlO has found very light pigmentation in infants which, with t.ime, grew in intensity and was almost completed by the age of 10 years. On the other hand, Prinzll stated that physiologic pigmentation does not appear
Volume 19 Number 1
Physiologic pigmentation
of skin
and
oral
mz~cosa
37
in children and is clinically visible only after puberty. In Letters to the Editor, published in the Journal of the American Medical Association in 1958, there is found a statement that “the physiological pigmentation usually develops fully during the second decade” of life.g The present study involved children 6 to 11 years of age. This, in itself, shows that all kinds of oral pigmentations appear in young children. The number of children in each age group was too small to permit a definite conclusion based on statistical values, but a trend was found which indicated that the intensity of pigmentation increases with age (Table IV). As in all previous works, it was found that in persons with oral pigmcntation the prevalent site of its appearance is the labial gingiva. It is not quite clear as yet whether this pigmentation is an expression of heredity or whether secondary environmental inflaences, such as stimulation by sunshine, dust particles, etc., upon this region are superimposed upon the hereditary etiology of oral pigmentation in dark-skinned persons. Since the location of labial pigment.ation might be subject to environmental influences, conclusions concerning hereditary trends of pigmentat,ion should be evaluated in regions of the oral cavity not exposed to such influences (for example, the buccal gingiva, the hard and soft palate, and the tongue). MonashlO found that the distribution of pigment, in descending order of frequency, was as follows: buccal gingiva, ha.rd palate, tongue, lips, and soft palate. Dummett” reported the distribution as follows: gingivae 67 per cent; hard palate, 61 per cent; buccal mucosa, 22 per cent; and tongue, 15 per cent. Both studies were carried out on Negroes, and the distribut,ion of pigment was very similar in both cases. In the present study no children were found with pigmentation on the tongue or lips, and only 2.6 per cent of the children examined had pigmentation of the hard palate. The distribution was as follows: labial gingivae, 50.4 per cent; buccal gingivae, 23 per cent; soft palate, 17 per cent; buccal mucosa 6.4 per cent (Table V). This finding is in contradistinction to’ the distribution of oral pigmentation reported in Negroes and leads to the thought that oral pigmentation in dark-skinned persons ma,y be dominated by genetic factors which vary in different ethnic groups. Further studies may be useful to verify this finding which, if found positive, could serve as a diagnostic aid in determination of ethnic origin. SUMMARY
Clinical examinations of 201 Jewish Yemenite children were carried out in order to determine the relationship between oral and cut.aneous pigmentation, The findings were as follows: 1. A correlation between oral and cutaneous pigmentation was proved statistically beyond doubt. 2. A relationship between the intensity of oral pigmentation and skin color was statistically established. 3. The incidence of pigmentation did not differ between the sexes. 4. The intensity of pigmentation seemed to increase with age.
O.S., O.&r. & 0.P. January,
5. There was a ccrt,ain to children of this ethnic distribution in Negroes. I wish to thank Dr. this study was conducted, in charge of orthodontics paper.
1965
pattern oi’ oral pigment. distributkn specific and different from patterns of pigment
group
J. Springer, Instructor in the Dental School, Jerusalem, at the time for arousing my interest in the subject and Dr. E. Koyomdjiski, a,t the Dental School, Jerusalem, for her help in the writing of this
REFERENCES
1. Adaehi, B.: Das Hautpigment beim Menschen und bei den Affen, Ztschr. Morphul. u. Anthropol. 6: 1, 1903 (Cited by Beekerz). 2. Becker, S. W.: Melanin Pigmentation, Arch. Dermat. & Syph. 16: 269-290, 1927. 3. Dummett. C. 0.: Clinical Observahions on Pigment Variations in Healthv Oral Tissues of the Negrb, J. D. Res. 24: 7-13, 1945. 4. Dummett, C. 0.: The Relationship Between Physiologic Pigmentation in the Oral and Cutaneous Tissues of the Negro. J. D. R’es. 25: X5-156, 1946. 5. Dummett, C. 0.: Physiologig pigmentation of the Oral and Cutaneous Tissues in the Negro, J. D. Res. 25: 421-432. 1946. 6. Edwards, E., and Duntley, Q.: The Pigments and Colour of Living Human Skin, Am. J. Anat. 65: l-33, 1939. 7. Kenney, J. A., Jr., and Curtis, A. C.: The Physiology of Pigmentation, 0x-U.. SURG., ORAL MED.
& ORAL
PATH.
7:
241-254,
1954.
8. Laidlaw, G. F., and Cal+, L. R.: Melanoblasts in the Gum, J. D. Res. 9. Letters to the Editor: Pigmentation of the Gums, J. A. M. A. 168: 10. Monash, 8.: Normal Pigmentation of the Oral Mucosae, Arch. Derm. & 1932. 11. Prinz, H.: Pigmentation of the Oral Mucous Membrane, Dental Cosmos. and Biochemistry 12. Volker, J. F., and Kenney, J. A., Jr.: The Physiology J. Periodont. 31: 346-355, 3960.
12: 534-537, 1932. 1296, 1958. Syph. 26: 139-147, 74: 554-561, 1932. of Pigmentation,