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Physiologic pigmentation of the gingiva in Israeli Jews of different ethnic origin
Physiologic pigmentation of the gingiva in Israeli Jews of different ethnic origin Meir Gorsky, D.M.D.,* Amos Buchner, D.M.D., MS.,* Dan Fundoianu-Dayan, D.M.D., MS.,* and Israel Aviv, D.M.D.,** Tel Aviv, Israel SCHOOL
OF DENTAL
MEDICINE,
TEL AVIV
UNIVERSITY
The prevalence of gingival physiologic pigmentation in three ethnic groups of a total of 2,465 Israeli Jews were determined. The distribution of this gingival pigmentation, according to anatomic parts and divisions, was examined. Results showed the presence of gingival pigmentation in 57.9% of the Eastern group, 49.3% of the Sephardic group, and 21 .l% of the Ashkenazi group. No indication of sex predilection was found. The most common site of pigmentation was the labial part of the gingiva, and the attached gingiva was the most common pigmented anatomic division. The group of Eastern Jews showed the highest pervalence of physiologic pigmentation in each of the anatomic parts and divisions of the gingiva. (ORAL SURC. 58:506-509, 1984)
M
ultifocal or diffuse pigmentation of the oral mucosa may be at a clinical sign of a pathologic process, such as Addison’s disease, Peutz-Jeghers syndrome, or heavy-metal ingestion.’ More often, however, melanin pigmentation is a benign characteristic of certain ethnic groups, in which case it is termed “racial pigmentation” or “physiologic pigmentation.” In a study on the relationship between ethnicity and physiologic pigmentation of the oral mucosa among three ethnic groups of Israeli Jews, Gorsky and associates* showed that the gingiva was the leading site of pigmentation. Buchner and his colleagues,3in a study of 18-year-old Israeli soldiers, noted that the prevalence of physiologic gingival pigmentation varied significantly according to ethnic background of the subjects. The purpose of the present study was to examine the distribution of the physiologic pigmentation of the gingiva in adult Israeli Jews, to determine the relationship between this distribution and ethnicity, and to find prevalence of the pigmentation in the different anatomic parts and divisions of the gingiva.
*Section of Oral Pathology and Oral Medicine. **Section of Oral Rehabilitation.
I. Distribution of physiologic gingival pigmentation according to anatomic part
Table
Upper Anatomic
part
Labial Buccal Anterior palatal/gingival Posterior palatal/gingival
MATERlALS
arch
Lower
arch
N
%
N
%
752 431 43 32
30.5 17.5 1.7 1.3
649 346 48 32
26.3 14.0 1.9 1.3
AND METHODS
The sample population consisted of 2,465 apparently healthy Israeli Jews (1,043 males, 1,422 females). Ages ranged from 18 to 90 years, with a mean age of 42.8 years for males and 40.5 years for females. The subjects were randomly selected from different parts of Israel (cities, villages, and kibbutzim) and from a wide spectrum of occupations. Data regarding ethnic background-Ashkenazi (originating from France, Germany, Central and Eastern Europe, North America, and parts of South America), Sephardic (originating from Spain, along the Coast of North Africa, Southern shores of the Mediterranean, part of the Balkans, and part of North America), or Eastern (originating from Iraq and other Middle East countries, Iran, Yemen, India, Kurdistan, Afganistan, Bukhara, and regions
Physiologic pigmentation of gingiva in three ethnic groups of Israeli Jews 507
Volume 58 Number 4
Table II. Prevalence of physiologic gingival pigmentation according to anatomic part in three Israeli
ethnic groups Lower arch
Upper arch Labial
Buccal
Ethnic group
N
%
Eastern Sephardic Ashkenazi
146 264 342
54.9 47.8 20.8
Anterior palalal
Posterior palatal
Labial
Buccal
Anterior lingual
Posterior lingual
N%N%N%N%N%N%N% 103 175 153
38.1 31.7 9.3
21 10 I2
7.9 1.8 0.7
of the Caucasus Mountains)-were recorded according to the criteria of Goodman4on the basis of place of birth of both parents. Subjects whose parents differed in ethnic background were excluded from the study to eliminate the possibility of the presence of extraneous hereditary factors with respect to pigmentation within the group. The examinations were performed under regular dental office conditions. The gingiva of each arch was divided into four anatomic parts: 1. Labial gingiva-the gingiva area extending from the distal aspect of the right canine to the distal aspect of the left canine. 2. Buccal gingiva-the area distal to the canines. 3. Anterior palatal/lingual gingiva-the palatal/ lingual area corresponding to the labial gingiva. 4. Posterior palatal/lingual gingiva-the palatal/ lingual area corresponding to the buccal gingiva. According to the classification of Dummett,s the gingiva was divided into four anatomic divisions: (1) attached gingiva, (2) papillary gingiva, (3) marginal gingiva, and (4) alveolar mucosa. Each gingival part and division was checked clinically for pigmentation according to the criteria described by Monash.6 All examinations were performed by three dentists who qualified by examining initially a group of 150 subjects with negligible error. Other checks were done during the period of the survey to ensure continuous stability. The data were analyzed by means of the chisquare test of significance. RESULTS
Classification of the subjects according to ethnicity indicated 266 Jews of Eastern origin (102 males, 164 females), 552 Jews of Sephardic origin (235 males, 3 17 females) and 1,647 Jews of Ashkenazi origin (706 males, 941 females).
I7 7 8
6.4 1.3 0.5
134 247 268
50.4 44.1 16.3
92 146 108
34.6 26.4 6.6
21 9 I8
7.9 I .6 1.1
I7 9 6
6.4 1.6 0.4
Gingival pigmentation was found in 774 (31.4%) of the entire sample. This included 154 (57.9%) of the Eastern group, 272 (49.3%) of the Sephardic group, and 348 (21 .I%) of the Ashkenazi group. No indication was found of sex predilection-320 males (30.7%) compared to 454 females (31.9%) (p > 0.1). The distribution of gingival pigmentation in relation to oral location is summarized in Table I. The most common site of pigmentation was the labial part of the gingiva, followed by the buccal gingiva, anterior palatal/lingual gingiva, and posterior palatal/lingual gingiva. Table II indicates the distribution of the location of gingival pigmentation in relation to ethnic origin. Eastern Jews showed the greatest prevalence of pigmentation in every anatomic part of the gingiva, and the Ashkenazi Jews showed the least pigmentation in every area. These differences were highly significant (p < 0.001). The most common pigmented anatomic division was the attached gingiva (678, or 27.5%), followed by the papillary gingiva (397 or 16.1%) (Table III). The marginal gingiva and the alveolar mucosa were pigmented to a much lesser degree. Again, the group of Eastern Jews showed the highest prevalence of physiologic pigmentation in each of the four anatomic divisions (p < 0.001). DISCUSSION
Few studies of physiologic gingival pigmentation have been made in various countries and among different races. In a study of 220 Negroes, Monash6 found gingival pigmentation in 89% of the cases. Dummett’ noted physiologic pigmentation of the gingiva in 72% of a group of 50 Negro patients from the United States. In a larger sample population (569 Negroes), he found physiologic gingival pigmentation in 67% of the cases8Raut and associates9 examined 2,000 males from Bombay, India, and recorded gingival pigmentation in 80%. Yoshiaki and co-workers10investigated gingival pigmentation in
508
Gorsky et al.
Oral Surg. October, 1984
III. Relationship betweendistribution of gingival pigmentation among four anatomic divisionsand ethnicity
Table
Ethnic
group --
Eastern Anatomic
Attached Papillary Marginal Alveolar
Sephardic
Ashkenazi
Mean
division
N
%
N
%
N
5%
N
70
gingiva gingiva gingiva mucosa
142 106 17 6
53.4 39.8 6.4 2.3
252 196 14 9
45.7 35.5 2.5 I .6
284 95 I6 15
17.2 5.8 1.0 0.9
678 397 47 30
21.5 16.1 I .9 1.2
827 Japanesesubjectsand noted an incidenceof 43% in males and 29.6% in females.Gingival pigmentation was found in 97.5% of 361 West Greenlanders studied by Jakobsen” and in 94.3% of 122 South African Bantu subjectsexaminedby Van Wyk.‘* Only two studies on the relationship of gingival pigmentation to ethnic origin have been made in Israel. Steigman,I3who examinedJewish children of Eastern origin, found physiologic pigmentation of the labial gingiva in 50.4% and pigmentation of the buccal gingiva in 23%. If the criteria of Goodman4 were applied to the study group of Is-year-old Israeli soldiersreported by Buchner and colleagues,jgingival pigmentation could be noted in 37.7%of those of Easternorigin, 12%of thoseof Sephardicorigin, and only 3.2% of those of Ashkenazi origin. In the presentstudy, physiologicgingival pigmentation was observedin 57.9% of Eastern Israeli Jews, 49.3% of Sephardic Jews, and 21.1% of Ashkenazi Jews. These differences in results may be due to the exclusion from the present study of subjects whose two parents differed in ethnic background, whereas Buchner and associates’basedtheir determination of ethnicity on the placeof birth of the father only, thus including subjectswith extraneoushereditary factors affecting pigmentation due to intermarriage. It is well known that Jewsof Easternorigin havea more highly pigmented skin than Sephardic Jews and that Ashkenazi Jews have the least pigmented skin of the three. The presentstudy showedthat the prevalenceof physiologic gingival pigmentation in these three ethnic groups varied according to the intensity of skin pigmentation. The direct relationship betweenskin and gingival pigmentation wasalso revealedby other investigatorsin different racesand ethnic groups.8,9+ I3 The lack of correlation betweenpigmentation and sex found in this study is similar to the results of Steigman” in Jewish children of Eastern origin and Reade,14who studied a group of Australian Aborigines.
In the present study, the prevalenceof gingival pigmentation was higher on the labial part of the gingiva than on the buccal and palatal/liagual parts of the arches. Dummett7v8noted in his studies that lesspigmentation was presenton the lingual than on the labial parts of the gingiva and that lessoccurred on the posterior gingival regionsthan on the anterior regions. Raut9 and Yoshiaki’Oand their colleagues also noted that the posterior gingival regions were lesspigmentedthan the anterior regions.Although it is considered that pigmentation of the gingiva is genetically determined, Dummett’ has suggested that environmental factors also play a role in its degree. He claimed that the lesser exposureof the lingual and posterior regions of the mouth to the effectsof light, variations in temperature,dust particles,and other irritating factors is responsiblefor the lower degreeof pigmentation in these areas. A review of the English literature of the last 25 yearsdid not revealany study regarding distribution of gingival pigmentation amongthe various anatomic divisions (attached, papillary, marginal, and alveolar mucosa). The present study revealed that the most common location was the attached gingiva (27.5%) followed, in decreasingorder, by the papillary gingiva, the marginal gingiva, and the alveolar mucosa. It could be postulated that, since the attachedgingiva is subjectedto most of the frictional forcesand other physical pigmentogenicstimuli, it is the most highly pigmented division of the gingiva. The authors would like to thank Pearl Lilos, Statistical Consulting Unit, Department of Statistics, Tel Aviv University, for the statistical analysis of the data. REFERE)(tCES 1. Salman L: Mercury precipitation in the oral cavity. ORAL SURG 22: 159-169, 1966. 2. Gorsky M, Buchner A, Moskona D, Aviv I: Physiologic pigmentation of the oral mucosa in Israeli Jews of different ethnic origin. Community Dent Oral Epidemiol 22: 188-190, 1984. 3. Buchner A, Melinek A, Shoenfeld Y: Physiologic pigmentation of the gingiva, Harefua 1: 12-13, 1976.
Volume 58 Number 4
Physiologic pigmentation of gingiva in three ethnic groups of Israeli Jews 509
4. Goodman RM: Genetic disorders among the Jewish people, Baltimore, 1979, John Hopkins Press, pp. 5-16. 5. Dummett CO: Normal variations in the clinical appearance of the gingivae. J Dent Med 18: 4-10, 1963. 6. Monash S: Normal pigmentation of the oral mucosa. Arch Dermatol. 26: 139-147, 1932. 7. Dummett CO: Clinical observations on pigmented variations in healthy oral tissues of the Negro. J Dent Res 24: 7-13, 1945. 8. Dummett CO: Physiologic pigmentation of the oral and cutaneous tissues in the Negro. J Dent Res 25: 421-432, 1946. 9. Raut RB, Baretto MA, Mehta FS, Sanjana MK, Shourie KL: Gingival pigmentation: Its incidences amongst the Indian adults. J All India Dent Assoc 26: I, 1954. IO. Yoshiaki A, Suetaka T, Sakuma I: A statistical investigation of gingival pigmentation. Shikwa Gakuho 56: 93-100, 1956. II. Jakobsen J: Pigmenteringsmdnstre i gingiva og mundslim-
hinde hos vestgrdnlaendere: en klinisk undersogelse.Tandlaegebladet 72: 1141-I 154, 1968. 12. Van Wyk CW: Mouth pigmentation patterns in a group of healthy South African Bantu. S Afr Med J 44: 177-180, 1970. 13. Steigman S: The relationship between physiologic pigmentation of the skin and oral mucosa in Yemenite Jews. ORAL SURG 19: 32-38, 1965. 14. Reade PC: Oral pigmentation in a group of Australian Aborigines (Abstr.) J Dent Res 41: 510, 1962. Reprint requests to:
Dr. Meir Gorsky Section of Oral Pathology and Oral Medicine School of Dental Medicine Sackler Faculty of Medicine Tel Aviv University Ramat Aviv 69978, Israel
OF DENTAL
MEDICINE,
TEL AVIV
UNIVERSITY
The prevalence of gingival physiologic pigmentation in three ethnic groups of a total of 2,465 Israeli Jews were determined. The distribution of this gingival pigmentation, according to anatomic parts and divisions, was examined. Results showed the presence of gingival pigmentation in 57.9% of the Eastern group, 49.3% of the Sephardic group, and 21 .l% of the Ashkenazi group. No indication of sex predilection was found. The most common site of pigmentation was the labial part of the gingiva, and the attached gingiva was the most common pigmented anatomic division. The group of Eastern Jews showed the highest pervalence of physiologic pigmentation in each of the anatomic parts and divisions of the gingiva. (ORAL SURC. 58:506-509, 1984)
M
ultifocal or diffuse pigmentation of the oral mucosa may be at a clinical sign of a pathologic process, such as Addison’s disease, Peutz-Jeghers syndrome, or heavy-metal ingestion.’ More often, however, melanin pigmentation is a benign characteristic of certain ethnic groups, in which case it is termed “racial pigmentation” or “physiologic pigmentation.” In a study on the relationship between ethnicity and physiologic pigmentation of the oral mucosa among three ethnic groups of Israeli Jews, Gorsky and associates* showed that the gingiva was the leading site of pigmentation. Buchner and his colleagues,3in a study of 18-year-old Israeli soldiers, noted that the prevalence of physiologic gingival pigmentation varied significantly according to ethnic background of the subjects. The purpose of the present study was to examine the distribution of the physiologic pigmentation of the gingiva in adult Israeli Jews, to determine the relationship between this distribution and ethnicity, and to find prevalence of the pigmentation in the different anatomic parts and divisions of the gingiva.
*Section of Oral Pathology and Oral Medicine. **Section of Oral Rehabilitation.
I. Distribution of physiologic gingival pigmentation according to anatomic part
Table
Upper Anatomic
part
Labial Buccal Anterior palatal/gingival Posterior palatal/gingival
MATERlALS
arch
Lower
arch
N
%
N
%
752 431 43 32
30.5 17.5 1.7 1.3
649 346 48 32
26.3 14.0 1.9 1.3
AND METHODS
The sample population consisted of 2,465 apparently healthy Israeli Jews (1,043 males, 1,422 females). Ages ranged from 18 to 90 years, with a mean age of 42.8 years for males and 40.5 years for females. The subjects were randomly selected from different parts of Israel (cities, villages, and kibbutzim) and from a wide spectrum of occupations. Data regarding ethnic background-Ashkenazi (originating from France, Germany, Central and Eastern Europe, North America, and parts of South America), Sephardic (originating from Spain, along the Coast of North Africa, Southern shores of the Mediterranean, part of the Balkans, and part of North America), or Eastern (originating from Iraq and other Middle East countries, Iran, Yemen, India, Kurdistan, Afganistan, Bukhara, and regions
Physiologic pigmentation of gingiva in three ethnic groups of Israeli Jews 507
Volume 58 Number 4
Table II. Prevalence of physiologic gingival pigmentation according to anatomic part in three Israeli
ethnic groups Lower arch
Upper arch Labial
Buccal
Ethnic group
N
%
Eastern Sephardic Ashkenazi
146 264 342
54.9 47.8 20.8
Anterior palalal
Posterior palatal
Labial
Buccal
Anterior lingual
Posterior lingual
N%N%N%N%N%N%N% 103 175 153
38.1 31.7 9.3
21 10 I2
7.9 1.8 0.7
of the Caucasus Mountains)-were recorded according to the criteria of Goodman4on the basis of place of birth of both parents. Subjects whose parents differed in ethnic background were excluded from the study to eliminate the possibility of the presence of extraneous hereditary factors with respect to pigmentation within the group. The examinations were performed under regular dental office conditions. The gingiva of each arch was divided into four anatomic parts: 1. Labial gingiva-the gingiva area extending from the distal aspect of the right canine to the distal aspect of the left canine. 2. Buccal gingiva-the area distal to the canines. 3. Anterior palatal/lingual gingiva-the palatal/ lingual area corresponding to the labial gingiva. 4. Posterior palatal/lingual gingiva-the palatal/ lingual area corresponding to the buccal gingiva. According to the classification of Dummett,s the gingiva was divided into four anatomic divisions: (1) attached gingiva, (2) papillary gingiva, (3) marginal gingiva, and (4) alveolar mucosa. Each gingival part and division was checked clinically for pigmentation according to the criteria described by Monash.6 All examinations were performed by three dentists who qualified by examining initially a group of 150 subjects with negligible error. Other checks were done during the period of the survey to ensure continuous stability. The data were analyzed by means of the chisquare test of significance. RESULTS
Classification of the subjects according to ethnicity indicated 266 Jews of Eastern origin (102 males, 164 females), 552 Jews of Sephardic origin (235 males, 3 17 females) and 1,647 Jews of Ashkenazi origin (706 males, 941 females).
I7 7 8
6.4 1.3 0.5
134 247 268
50.4 44.1 16.3
92 146 108
34.6 26.4 6.6
21 9 I8
7.9 I .6 1.1
I7 9 6
6.4 1.6 0.4
Gingival pigmentation was found in 774 (31.4%) of the entire sample. This included 154 (57.9%) of the Eastern group, 272 (49.3%) of the Sephardic group, and 348 (21 .I%) of the Ashkenazi group. No indication was found of sex predilection-320 males (30.7%) compared to 454 females (31.9%) (p > 0.1). The distribution of gingival pigmentation in relation to oral location is summarized in Table I. The most common site of pigmentation was the labial part of the gingiva, followed by the buccal gingiva, anterior palatal/lingual gingiva, and posterior palatal/lingual gingiva. Table II indicates the distribution of the location of gingival pigmentation in relation to ethnic origin. Eastern Jews showed the greatest prevalence of pigmentation in every anatomic part of the gingiva, and the Ashkenazi Jews showed the least pigmentation in every area. These differences were highly significant (p < 0.001). The most common pigmented anatomic division was the attached gingiva (678, or 27.5%), followed by the papillary gingiva (397 or 16.1%) (Table III). The marginal gingiva and the alveolar mucosa were pigmented to a much lesser degree. Again, the group of Eastern Jews showed the highest prevalence of physiologic pigmentation in each of the four anatomic divisions (p < 0.001). DISCUSSION
Few studies of physiologic gingival pigmentation have been made in various countries and among different races. In a study of 220 Negroes, Monash6 found gingival pigmentation in 89% of the cases. Dummett’ noted physiologic pigmentation of the gingiva in 72% of a group of 50 Negro patients from the United States. In a larger sample population (569 Negroes), he found physiologic gingival pigmentation in 67% of the cases8Raut and associates9 examined 2,000 males from Bombay, India, and recorded gingival pigmentation in 80%. Yoshiaki and co-workers10investigated gingival pigmentation in
508
Gorsky et al.
Oral Surg. October, 1984
III. Relationship betweendistribution of gingival pigmentation among four anatomic divisionsand ethnicity
Table
Ethnic
group --
Eastern Anatomic
Attached Papillary Marginal Alveolar
Sephardic
Ashkenazi
Mean
division
N
%
N
%
N
5%
N
70
gingiva gingiva gingiva mucosa
142 106 17 6
53.4 39.8 6.4 2.3
252 196 14 9
45.7 35.5 2.5 I .6
284 95 I6 15
17.2 5.8 1.0 0.9
678 397 47 30
21.5 16.1 I .9 1.2
827 Japanesesubjectsand noted an incidenceof 43% in males and 29.6% in females.Gingival pigmentation was found in 97.5% of 361 West Greenlanders studied by Jakobsen” and in 94.3% of 122 South African Bantu subjectsexaminedby Van Wyk.‘* Only two studies on the relationship of gingival pigmentation to ethnic origin have been made in Israel. Steigman,I3who examinedJewish children of Eastern origin, found physiologic pigmentation of the labial gingiva in 50.4% and pigmentation of the buccal gingiva in 23%. If the criteria of Goodman4 were applied to the study group of Is-year-old Israeli soldiersreported by Buchner and colleagues,jgingival pigmentation could be noted in 37.7%of those of Easternorigin, 12%of thoseof Sephardicorigin, and only 3.2% of those of Ashkenazi origin. In the presentstudy, physiologicgingival pigmentation was observedin 57.9% of Eastern Israeli Jews, 49.3% of Sephardic Jews, and 21.1% of Ashkenazi Jews. These differences in results may be due to the exclusion from the present study of subjects whose two parents differed in ethnic background, whereas Buchner and associates’basedtheir determination of ethnicity on the placeof birth of the father only, thus including subjectswith extraneoushereditary factors affecting pigmentation due to intermarriage. It is well known that Jewsof Easternorigin havea more highly pigmented skin than Sephardic Jews and that Ashkenazi Jews have the least pigmented skin of the three. The presentstudy showedthat the prevalenceof physiologic gingival pigmentation in these three ethnic groups varied according to the intensity of skin pigmentation. The direct relationship betweenskin and gingival pigmentation wasalso revealedby other investigatorsin different racesand ethnic groups.8,9+ I3 The lack of correlation betweenpigmentation and sex found in this study is similar to the results of Steigman” in Jewish children of Eastern origin and Reade,14who studied a group of Australian Aborigines.
In the present study, the prevalenceof gingival pigmentation was higher on the labial part of the gingiva than on the buccal and palatal/liagual parts of the arches. Dummett7v8noted in his studies that lesspigmentation was presenton the lingual than on the labial parts of the gingiva and that lessoccurred on the posterior gingival regionsthan on the anterior regions. Raut9 and Yoshiaki’Oand their colleagues also noted that the posterior gingival regions were lesspigmentedthan the anterior regions.Although it is considered that pigmentation of the gingiva is genetically determined, Dummett’ has suggested that environmental factors also play a role in its degree. He claimed that the lesser exposureof the lingual and posterior regions of the mouth to the effectsof light, variations in temperature,dust particles,and other irritating factors is responsiblefor the lower degreeof pigmentation in these areas. A review of the English literature of the last 25 yearsdid not revealany study regarding distribution of gingival pigmentation amongthe various anatomic divisions (attached, papillary, marginal, and alveolar mucosa). The present study revealed that the most common location was the attached gingiva (27.5%) followed, in decreasingorder, by the papillary gingiva, the marginal gingiva, and the alveolar mucosa. It could be postulated that, since the attachedgingiva is subjectedto most of the frictional forcesand other physical pigmentogenicstimuli, it is the most highly pigmented division of the gingiva. The authors would like to thank Pearl Lilos, Statistical Consulting Unit, Department of Statistics, Tel Aviv University, for the statistical analysis of the data. REFERE)(tCES 1. Salman L: Mercury precipitation in the oral cavity. ORAL SURG 22: 159-169, 1966. 2. Gorsky M, Buchner A, Moskona D, Aviv I: Physiologic pigmentation of the oral mucosa in Israeli Jews of different ethnic origin. Community Dent Oral Epidemiol 22: 188-190, 1984. 3. Buchner A, Melinek A, Shoenfeld Y: Physiologic pigmentation of the gingiva, Harefua 1: 12-13, 1976.
Volume 58 Number 4
Physiologic pigmentation of gingiva in three ethnic groups of Israeli Jews 509
4. Goodman RM: Genetic disorders among the Jewish people, Baltimore, 1979, John Hopkins Press, pp. 5-16. 5. Dummett CO: Normal variations in the clinical appearance of the gingivae. J Dent Med 18: 4-10, 1963. 6. Monash S: Normal pigmentation of the oral mucosa. Arch Dermatol. 26: 139-147, 1932. 7. Dummett CO: Clinical observations on pigmented variations in healthy oral tissues of the Negro. J Dent Res 24: 7-13, 1945. 8. Dummett CO: Physiologic pigmentation of the oral and cutaneous tissues in the Negro. J Dent Res 25: 421-432, 1946. 9. Raut RB, Baretto MA, Mehta FS, Sanjana MK, Shourie KL: Gingival pigmentation: Its incidences amongst the Indian adults. J All India Dent Assoc 26: I, 1954. IO. Yoshiaki A, Suetaka T, Sakuma I: A statistical investigation of gingival pigmentation. Shikwa Gakuho 56: 93-100, 1956. II. Jakobsen J: Pigmenteringsmdnstre i gingiva og mundslim-
hinde hos vestgrdnlaendere: en klinisk undersogelse.Tandlaegebladet 72: 1141-I 154, 1968. 12. Van Wyk CW: Mouth pigmentation patterns in a group of healthy South African Bantu. S Afr Med J 44: 177-180, 1970. 13. Steigman S: The relationship between physiologic pigmentation of the skin and oral mucosa in Yemenite Jews. ORAL SURG 19: 32-38, 1965. 14. Reade PC: Oral pigmentation in a group of Australian Aborigines (Abstr.) J Dent Res 41: 510, 1962. Reprint requests to:
Dr. Meir Gorsky Section of Oral Pathology and Oral Medicine School of Dental Medicine Sackler Faculty of Medicine Tel Aviv University Ramat Aviv 69978, Israel