- Email: [email protected]
Relationship between tooth shade value and skin color: An observational study
Relationship between tooth shade value and skin color: An observational study Leila Jahangiri, BDS, DMD, MMSc,a Suzanne B. Reinhardt, DMD,b Rita V. Mehra, DDS, MSD,c and Pamela B. Matheson, PhDd University of Medicine and Dentistry of New Jersey, Newark, N.J. Statement of problem. There is limited scientific information on the relationship between tooth shade and skin color. This lack of knowledge may impact the ability of the prosthodontist to select artificial teeth that complement the facial complexion of the patient. Purpose. This observational study explored the possibility of a relationship between tooth shade and skin color. Material and methods. A total of 119 individuals aged 18 to 80 years participated in this observational study. Two investigators calibrated for examining tooth shade performed all examinations. A Vita-Lumin shade guide was used to examine either the maxillary right or left central incisor, one of which had to be restoration- and caries-free for study inclusion. Tooth shades were divided into 4 categories according to value, and skin tones were divided into 4 categories (fair, fair/medium, medium, and dark) with the use of L’Oreal True Illusion compact makeup shades as a guide. Categorical modeling with chi-square analysis and Fisher’s exact tests was used to analyze the data (α=.05). Results. No interaction among age, skin color, and tooth shade or gender, skin color, and tooth shade was found; however, age was associated with tooth shade (P<.001). Older persons were more likely to have teeth with lower values (darker). Among those aged 60 and older, 85% had teeth in the medium and low range values compared with 17% of those younger than 31. Significant tooth shade differences were discovered among patients with different skin colors (P<.05). Among those with low values (darker teeth), 50% were of fair complexion and 17% were of dark complexion (P<.001). Conclusion. Within the limitations of this study, tooth shade value and skin color were inversely related. Older adults were more likely to have darker teeth (lower value). (J Prosthet Dent 2002;87:149-52.)
CLINICAL IMPLICATIONS Based on the relationships discovered in this observational study, skin color may be a useful guide for the selection of tooth shade in removable and full-mouth reconstructions to achieve a more natural appearance, especially among the elderly and persons with darker skin tones.
A
perception among prosthodontists and restorative dentists has been that individuals with darker skin colors have lighter shades of teeth. This perception is commonly explained by the illusion of greater contrast between skin color and tooth shade. Studies related to staining and altering tooth shades are abundant in the dental literature; the focus of these investigations often has been divided between evaluation of extrinsic and intrinsic staining factors. Studies on extrinsic factors have included observations on the effects of diet,
Presented before the International Association for Dental Research (IADR), Washington DC, April 2000. aAssistant Professor, Department of Prosthodontics and Biomaterials. bGeneral Practice Resident, Manhattan V. A. Medical Center, N.Y. cProfessor, Department of Prosthodontics and Biomaterials. dActing Associate Dean, New Jersey Dental School. FEBRUARY 2002
smoking, xerostomia, and restorations.1,2 Intrinsic factors have included congenital defects of enamel or dentin such as amelogenesis and dentinogenesis imperfecta, environmental factors such as tetracycline staining, traumatic injury, dental caries, and aging.3-5 Several studies have shown that the aging process has a profound effect on the shade of teeth, in that teeth become darker and less translucent with age.6-8 The Munsell system of color identification uses hue, value, and chroma to describe colors of teeth. Hue refers to the dimension of color that distinguishes one family of color from another (red, blue, yellow, and so on). Value describes the dimension of color that denotes relative blackness or whiteness/brightness. Chroma is the dimension that describes the saturation, intensity, or strength of a hue. Two methods are commonly used to analyze the color of natural teeth and shade guides. The first and most common method THE JOURNAL OF PROSTHETIC DENTISTRY 149
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JAHANGIRI ET AL
Fig. 1. Illustrations of skin tones: fair (A), fair/medium (B), medium (C), and dark (D).
involves visual comparison, and the second method involves the use of an instrument such as a colorimeter. Both techniques have inherent inaccuracies. Visual examination requires trained and experienced individuals,9 and shade selection can be affected by illumination and surrounding tissues. Instrumental measurements may be complicated by setup difficulty and heat produced by the instrument in repeated measurements, which could cause discomfort to the subject or failure of the instrument to maintain its calibration.10,11 The purpose of this observational study was to shed light on the relationship between facial and tooth color values since there is a paucity of evidence-based data on this subject.
MATERIAL AND METHODS One hundred nineteen patients were included in the study via convenience sampling. The patients were evaluated to determine their suitability for the study. Practical but not prohibitive exclusion criteria were created to reduce the effects of intrinsic and extrinsic staining on this sample. Teeth that required or had received endodontic therapy or restorations were excluded from the study because many restorations alter natural tooth shades. The following patients also were excluded: those who had active orthodontic appliances that interfered with shade selection, those who reported that they tanned their skin, 3-8 and those 150
whose histories included bleaching procedures, radiation therapy, xerostomia, tetracycline staining, abnormalities in tooth development, or smoking. The patients ranged in age from 18 to 80 years and were divided into 4 age groups (18 to 30, 31 to 45, 46 to 60, and 61 to 80 years). The gender of all patients was recorded. Two individuals calibrated for examination of tooth shades performed all examinations. Calibration was performed with the use of 25 patients as pilot participants. The rate of agreement between examiners was 92% for tooth shade evaluations. A Vita-Lumin (Vita Zahnfabrik, H. Rauter GmbH and Co KG, Bad Sackingen, Germany) shade guide was selected to examine either the maxillary left or right central incisor, which had to be free of restorations and dental caries. Female patients were asked to remove lipstick prior to examination. An individual shade tab was positioned directly behind the tooth under examination and compared to the middle third of the crown. Shades were divided into 4 categories based on the reported values of the Vita-Lumin shade guide: the highest value group (shades A1, B1, A2, B2); high value group (shades C1, D2, A3, D4); medium value group (shades B3, B4, C2, D3); and low value group (shades A3.5, C3, A4, C4).12 Examinations were accomplished with natural light and a neutral background. A light blue color was viewed between examinations for the calibration of the eye.13 Because VOLUME 87 NUMBER 2
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THE JOURNAL OF PROSTHETIC DENTISTRY
Table I. Comparison of tooth shade value (lightness) and age for 119 study participants* Age (years)
18-30 31-45 46-60 61-80 Total
Highest value
36 9 3 1 49
(55%) (38%) (14%) (14%) (41%)
High value
19 (29%) 9 (38%) 4 (18%) 0 32 (27%)
Medium value
10 5 10 1 26
(15%) (21%) (46%) (14%) (22%)
Low value
1 (2%) 1 (4%) 5 (23%) 5 (71%) 12 (10%)
Total
66 (56%) 24 (20%) 22 (19%) 7 (6%) 119
*P<.001.
Table II. Comparison of skin tone and tooth shade value (lightness) among 119 study participants* Skin tone
Dark Medium Fair/medium Fair Total
Highest value
12 13 8 16 49
(24%) (27%) (16%) (33%) (41%)
High value
5 10 9 8 32
(16%) (31%) (28%) (25%) (27%)
Medium value
0 3 8 15 26
(12%) (31%) (58%) (22%)
Low value
2 0 4 6 12
(17%) (33%) (50%) (10%)
Total
19 (16%) 26 (22%) 29 (24%) 45 (38%) 119
*P<.05.
dehydration affects the shade of teeth and hours are required for the teeth to return to their original shade,6,14 patients were examined prior to dental treatment. Skin tones were divided into 4 categories (fair, fair/medium, medium, and dark) with the use of L’Oreal (Paris, France) True Illusion compact makeup shades as a guide. The rate of agreement between examiners was 96% for skin tone evaluations. Skin shade determinations were acquired from the hands of patients so that the area was free of makeup or residues. The “light” and “medium” shade groups of the L’Oreal True Illusion compacts corresponded to the fair skin group, the “deep” shades of the compact corresponded to the fair/medium skin group, and the “deeper” shades of the compact corresponded to the medium skin group. Shades beyond the deeper shades of the compact were categorized in the dark skin group (Fig. 1). Categorical modeling with use of log likelihood estimation, chi-square analysis, and Fisher’s exact tests was conducted with SAS (SAS Institute, Cary, N.C.). A priori statistical significance was set at α=.05.
RESULTS Separate categorical models failed to detect 3-way interactions among gender and age with the outcomes (model 1 = age, skin color, and shade of teeth; model 2 = gender, skin color, and shade of teeth). Therefore, chi-squared tests of independence were selected to evaluate bivariate relationships among variables. When necessary, Fisher’s exact tests were used. Age was associated with tooth shade value (P<.001) (Table I). Older persons were more likely to have teeth with lower values. Among those aged 60 and older, 85% FEBRUARY 2002
had teeth in the medium and low range values compared to 17% of persons younger than 31. There was a significant relationship between skin color and tooth shade (P<.05). Among those with low tooth values (darker teeth), 50% had fair skin whereas only 17% had dark skin (Table II).
DISCUSSION While this study confirmed an association between age and tooth shade, neither gender nor age had a bearing on the relationship between tooth shade and skin color. Persons with medium and dark skin were more likely to have teeth in the highest value category than persons with fair and fair/medium skin tones. The Vita-Lumin shade guide for teeth was selected because of its routine use in the United States. This shade guide consists of 16 shades organized by chroma level within 4 hue groups of A, B, C, and D. The shades are also numbered to discriminate lightness and darkness values. In a study by Schwabacher and Goodkind,12 the value of each tab in this shade guide was determined. The authors showed that the numerical values given to each tab can cause confusion. For example, D3 shade is lower in value than D4 despite the fact that lower numbers typically represent higher values. Thus, in the present study, tooth shade value groups were assigned based on the published values of each tab. In a study on the color of natural central incisors in vivo, Hasegawa et al11 also evaluated the Vita-Lumin shade guide. Using a spectroradiometric color computer, they expressed color data according to lightness (L* according to CIELAB color spaces). Their study revealed that the lightness values of natural teeth were consistent with the Vita-Lumin shade guides at any particular site. For example, the L* val151
THE JOURNAL OF PROSTHETIC DENTISTRY
ues for the middle portion of the teeth were not considered significantly different than that of Vita-Lumin shade guide. Given these findings, value was used to discriminate skin and tooth shades in the present study. Several of the patients had teeth lighter than any category in the Vita-Lumin shade guide; they were categorized in the highest value shade category. It became apparent that commonly used shade guides may be insufficient and that this deficiency may make communication with the dental laboratory difficult when restorations are matched to existing teeth. This finding is consistent with a previous report.11 There is a lack of literature with regard to standard shade guides used for skin tones. In the present study, a L’Oreal makeup guide was selected because of the number of shades available (15) and the fact that the range appeared to apply to a wider spectrum of skin tones than other shade guides within the cosmetic industry. The extensive use of this shade guide within the industry is based on its face validity. However, darker ranges that would adequately describe skin tones among the black population are not sufficiently represented in this shade guide. Persons with dark skin shades not represented in the skin shade guide were placed in the “dark” category. While this study was not designed to determine whether shade differences were contained within enamel or dentinal structures or a combination of the two, this would be of interest, as it may influence the effectiveness of bleaching procedures. For an edentulous patient and a dentist selecting artificial teeth, the results of this study may serve as an aid in the development of natural-looking prostheses for different populations.
CONCLUSIONS The results of this observational study suggest that there is a significant relationship between tooth shade and skin color. Persons with medium-to-dark skin tones were more likely to have teeth with higher values (lighter), whereas individuals with lighter skin
152
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tones tended to have teeth with lower values (darker), regardless of gender or age. REFERENCES 1. Fischer D, Bailey JH. Vital bleaching for aesthetic improvement. Pract Periodontics Aesthet Dent 1995;7:61-4. 2. Seale NS, Thrash WJ. Systematic assessment of color removal following vital bleaching of intrinsically stained teeth. J Dent Res 1985;64:457-61. 3. Chiappinelli JA, Walton RE. Tooth discoloration resulting from long-term tetracycline therapy: a case report. Quintessence Int 1992;23:539-41. 4. Dreizen S. Oral complications of cancer therapies. Description and incidence of oral complications. NCI Monogr 1990;9:11-5. 5. Telivuo M, Murtomaa H, Lahtinen A. Observations and concepts of the oral health consequences of tobacco use of Finnish periodontists and dentists. J Clin Periodontol 1992;19:15-8. 6. Brodbelt RH, O’Brien WJ, Fan PL, Frazer-Dib JG, Yu R. Translucency of human dental enamel. J Dent Res 1981;60:1749-53. 7. Burchett PJ Jr, Christensen LC. Estimating age and sex by using color, form, and alignment of anterior teeth. J Prosthet Dent 1988;59:175-9. 8. Solheim T. Dental color as an indicator of age. Gerodontics 1988;4:1148. 9. Goodkind RJ, Keenan KM, Schwabacher WB. A comparison of Chromascan and spectrophotometric color measurements of 100 natural teeth. J Prosthet Dent 1985;53:105-9. 10. Goodkind RJ, Schwabacher WB. Use of a fiber-optic colorimeter for in vivo color measurements of 2830 anterior teeth. J Prosthet Dent 1987;58:535-42. 11. Hasegawa A, Ikeda I, Kawaguchi S. Color and translucency of in vivo natural central incisors. J Prosthet Dent 2000;83:418-23. 12. Schwabacher WB, Goodkind RJ. Three-dimensional color coordinates of natural teeth compared with three shade guides. J Prosthet Dent 1990;64:425-31. 13. Sorensen JA, Torres TJ. Improved color matching of metal ceramic restorations. Part II. Procedures for visual communication. J Prosthet Dent 1987;58:669-77. 14. Miller A, Long J, Cole J, Staffanou R. Shade selection and laboratory communication. Quintessence Int 1993;24:305-9. Reprint requests to: DR LEILA JAHANGIRI DEPARTMENT OF PROSTHODONTICS AND BIOMATERIALS UMDNJ – NEW JERSEY DENTAL SCHOOL 110 BERGEN ST, ROOM D830 NEWARK, NJ 07103-1568 FAX: (973)972-0370 E-MAIL: [email protected] Copyright © 2002 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2002/$35.00 + 0. 10/1/121109
doi:10.1067/mpr.2002.121109
VOLUME 87 NUMBER 2
CLINICAL IMPLICATIONS Based on the relationships discovered in this observational study, skin color may be a useful guide for the selection of tooth shade in removable and full-mouth reconstructions to achieve a more natural appearance, especially among the elderly and persons with darker skin tones.
A
perception among prosthodontists and restorative dentists has been that individuals with darker skin colors have lighter shades of teeth. This perception is commonly explained by the illusion of greater contrast between skin color and tooth shade. Studies related to staining and altering tooth shades are abundant in the dental literature; the focus of these investigations often has been divided between evaluation of extrinsic and intrinsic staining factors. Studies on extrinsic factors have included observations on the effects of diet,
Presented before the International Association for Dental Research (IADR), Washington DC, April 2000. aAssistant Professor, Department of Prosthodontics and Biomaterials. bGeneral Practice Resident, Manhattan V. A. Medical Center, N.Y. cProfessor, Department of Prosthodontics and Biomaterials. dActing Associate Dean, New Jersey Dental School. FEBRUARY 2002
smoking, xerostomia, and restorations.1,2 Intrinsic factors have included congenital defects of enamel or dentin such as amelogenesis and dentinogenesis imperfecta, environmental factors such as tetracycline staining, traumatic injury, dental caries, and aging.3-5 Several studies have shown that the aging process has a profound effect on the shade of teeth, in that teeth become darker and less translucent with age.6-8 The Munsell system of color identification uses hue, value, and chroma to describe colors of teeth. Hue refers to the dimension of color that distinguishes one family of color from another (red, blue, yellow, and so on). Value describes the dimension of color that denotes relative blackness or whiteness/brightness. Chroma is the dimension that describes the saturation, intensity, or strength of a hue. Two methods are commonly used to analyze the color of natural teeth and shade guides. The first and most common method THE JOURNAL OF PROSTHETIC DENTISTRY 149
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JAHANGIRI ET AL
Fig. 1. Illustrations of skin tones: fair (A), fair/medium (B), medium (C), and dark (D).
involves visual comparison, and the second method involves the use of an instrument such as a colorimeter. Both techniques have inherent inaccuracies. Visual examination requires trained and experienced individuals,9 and shade selection can be affected by illumination and surrounding tissues. Instrumental measurements may be complicated by setup difficulty and heat produced by the instrument in repeated measurements, which could cause discomfort to the subject or failure of the instrument to maintain its calibration.10,11 The purpose of this observational study was to shed light on the relationship between facial and tooth color values since there is a paucity of evidence-based data on this subject.
MATERIAL AND METHODS One hundred nineteen patients were included in the study via convenience sampling. The patients were evaluated to determine their suitability for the study. Practical but not prohibitive exclusion criteria were created to reduce the effects of intrinsic and extrinsic staining on this sample. Teeth that required or had received endodontic therapy or restorations were excluded from the study because many restorations alter natural tooth shades. The following patients also were excluded: those who had active orthodontic appliances that interfered with shade selection, those who reported that they tanned their skin, 3-8 and those 150
whose histories included bleaching procedures, radiation therapy, xerostomia, tetracycline staining, abnormalities in tooth development, or smoking. The patients ranged in age from 18 to 80 years and were divided into 4 age groups (18 to 30, 31 to 45, 46 to 60, and 61 to 80 years). The gender of all patients was recorded. Two individuals calibrated for examination of tooth shades performed all examinations. Calibration was performed with the use of 25 patients as pilot participants. The rate of agreement between examiners was 92% for tooth shade evaluations. A Vita-Lumin (Vita Zahnfabrik, H. Rauter GmbH and Co KG, Bad Sackingen, Germany) shade guide was selected to examine either the maxillary left or right central incisor, which had to be free of restorations and dental caries. Female patients were asked to remove lipstick prior to examination. An individual shade tab was positioned directly behind the tooth under examination and compared to the middle third of the crown. Shades were divided into 4 categories based on the reported values of the Vita-Lumin shade guide: the highest value group (shades A1, B1, A2, B2); high value group (shades C1, D2, A3, D4); medium value group (shades B3, B4, C2, D3); and low value group (shades A3.5, C3, A4, C4).12 Examinations were accomplished with natural light and a neutral background. A light blue color was viewed between examinations for the calibration of the eye.13 Because VOLUME 87 NUMBER 2
JAHANGIRI ET AL
THE JOURNAL OF PROSTHETIC DENTISTRY
Table I. Comparison of tooth shade value (lightness) and age for 119 study participants* Age (years)
18-30 31-45 46-60 61-80 Total
Highest value
36 9 3 1 49
(55%) (38%) (14%) (14%) (41%)
High value
19 (29%) 9 (38%) 4 (18%) 0 32 (27%)
Medium value
10 5 10 1 26
(15%) (21%) (46%) (14%) (22%)
Low value
1 (2%) 1 (4%) 5 (23%) 5 (71%) 12 (10%)
Total
66 (56%) 24 (20%) 22 (19%) 7 (6%) 119
*P<.001.
Table II. Comparison of skin tone and tooth shade value (lightness) among 119 study participants* Skin tone
Dark Medium Fair/medium Fair Total
Highest value
12 13 8 16 49
(24%) (27%) (16%) (33%) (41%)
High value
5 10 9 8 32
(16%) (31%) (28%) (25%) (27%)
Medium value
0 3 8 15 26
(12%) (31%) (58%) (22%)
Low value
2 0 4 6 12
(17%) (33%) (50%) (10%)
Total
19 (16%) 26 (22%) 29 (24%) 45 (38%) 119
*P<.05.
dehydration affects the shade of teeth and hours are required for the teeth to return to their original shade,6,14 patients were examined prior to dental treatment. Skin tones were divided into 4 categories (fair, fair/medium, medium, and dark) with the use of L’Oreal (Paris, France) True Illusion compact makeup shades as a guide. The rate of agreement between examiners was 96% for skin tone evaluations. Skin shade determinations were acquired from the hands of patients so that the area was free of makeup or residues. The “light” and “medium” shade groups of the L’Oreal True Illusion compacts corresponded to the fair skin group, the “deep” shades of the compact corresponded to the fair/medium skin group, and the “deeper” shades of the compact corresponded to the medium skin group. Shades beyond the deeper shades of the compact were categorized in the dark skin group (Fig. 1). Categorical modeling with use of log likelihood estimation, chi-square analysis, and Fisher’s exact tests was conducted with SAS (SAS Institute, Cary, N.C.). A priori statistical significance was set at α=.05.
RESULTS Separate categorical models failed to detect 3-way interactions among gender and age with the outcomes (model 1 = age, skin color, and shade of teeth; model 2 = gender, skin color, and shade of teeth). Therefore, chi-squared tests of independence were selected to evaluate bivariate relationships among variables. When necessary, Fisher’s exact tests were used. Age was associated with tooth shade value (P<.001) (Table I). Older persons were more likely to have teeth with lower values. Among those aged 60 and older, 85% FEBRUARY 2002
had teeth in the medium and low range values compared to 17% of persons younger than 31. There was a significant relationship between skin color and tooth shade (P<.05). Among those with low tooth values (darker teeth), 50% had fair skin whereas only 17% had dark skin (Table II).
DISCUSSION While this study confirmed an association between age and tooth shade, neither gender nor age had a bearing on the relationship between tooth shade and skin color. Persons with medium and dark skin were more likely to have teeth in the highest value category than persons with fair and fair/medium skin tones. The Vita-Lumin shade guide for teeth was selected because of its routine use in the United States. This shade guide consists of 16 shades organized by chroma level within 4 hue groups of A, B, C, and D. The shades are also numbered to discriminate lightness and darkness values. In a study by Schwabacher and Goodkind,12 the value of each tab in this shade guide was determined. The authors showed that the numerical values given to each tab can cause confusion. For example, D3 shade is lower in value than D4 despite the fact that lower numbers typically represent higher values. Thus, in the present study, tooth shade value groups were assigned based on the published values of each tab. In a study on the color of natural central incisors in vivo, Hasegawa et al11 also evaluated the Vita-Lumin shade guide. Using a spectroradiometric color computer, they expressed color data according to lightness (L* according to CIELAB color spaces). Their study revealed that the lightness values of natural teeth were consistent with the Vita-Lumin shade guides at any particular site. For example, the L* val151
THE JOURNAL OF PROSTHETIC DENTISTRY
ues for the middle portion of the teeth were not considered significantly different than that of Vita-Lumin shade guide. Given these findings, value was used to discriminate skin and tooth shades in the present study. Several of the patients had teeth lighter than any category in the Vita-Lumin shade guide; they were categorized in the highest value shade category. It became apparent that commonly used shade guides may be insufficient and that this deficiency may make communication with the dental laboratory difficult when restorations are matched to existing teeth. This finding is consistent with a previous report.11 There is a lack of literature with regard to standard shade guides used for skin tones. In the present study, a L’Oreal makeup guide was selected because of the number of shades available (15) and the fact that the range appeared to apply to a wider spectrum of skin tones than other shade guides within the cosmetic industry. The extensive use of this shade guide within the industry is based on its face validity. However, darker ranges that would adequately describe skin tones among the black population are not sufficiently represented in this shade guide. Persons with dark skin shades not represented in the skin shade guide were placed in the “dark” category. While this study was not designed to determine whether shade differences were contained within enamel or dentinal structures or a combination of the two, this would be of interest, as it may influence the effectiveness of bleaching procedures. For an edentulous patient and a dentist selecting artificial teeth, the results of this study may serve as an aid in the development of natural-looking prostheses for different populations.
CONCLUSIONS The results of this observational study suggest that there is a significant relationship between tooth shade and skin color. Persons with medium-to-dark skin tones were more likely to have teeth with higher values (lighter), whereas individuals with lighter skin
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tones tended to have teeth with lower values (darker), regardless of gender or age. REFERENCES 1. Fischer D, Bailey JH. Vital bleaching for aesthetic improvement. Pract Periodontics Aesthet Dent 1995;7:61-4. 2. Seale NS, Thrash WJ. Systematic assessment of color removal following vital bleaching of intrinsically stained teeth. J Dent Res 1985;64:457-61. 3. Chiappinelli JA, Walton RE. Tooth discoloration resulting from long-term tetracycline therapy: a case report. Quintessence Int 1992;23:539-41. 4. Dreizen S. Oral complications of cancer therapies. Description and incidence of oral complications. NCI Monogr 1990;9:11-5. 5. Telivuo M, Murtomaa H, Lahtinen A. Observations and concepts of the oral health consequences of tobacco use of Finnish periodontists and dentists. J Clin Periodontol 1992;19:15-8. 6. Brodbelt RH, O’Brien WJ, Fan PL, Frazer-Dib JG, Yu R. Translucency of human dental enamel. J Dent Res 1981;60:1749-53. 7. Burchett PJ Jr, Christensen LC. Estimating age and sex by using color, form, and alignment of anterior teeth. J Prosthet Dent 1988;59:175-9. 8. Solheim T. Dental color as an indicator of age. Gerodontics 1988;4:1148. 9. Goodkind RJ, Keenan KM, Schwabacher WB. A comparison of Chromascan and spectrophotometric color measurements of 100 natural teeth. J Prosthet Dent 1985;53:105-9. 10. Goodkind RJ, Schwabacher WB. Use of a fiber-optic colorimeter for in vivo color measurements of 2830 anterior teeth. J Prosthet Dent 1987;58:535-42. 11. Hasegawa A, Ikeda I, Kawaguchi S. Color and translucency of in vivo natural central incisors. J Prosthet Dent 2000;83:418-23. 12. Schwabacher WB, Goodkind RJ. Three-dimensional color coordinates of natural teeth compared with three shade guides. J Prosthet Dent 1990;64:425-31. 13. Sorensen JA, Torres TJ. Improved color matching of metal ceramic restorations. Part II. Procedures for visual communication. J Prosthet Dent 1987;58:669-77. 14. Miller A, Long J, Cole J, Staffanou R. Shade selection and laboratory communication. Quintessence Int 1993;24:305-9. Reprint requests to: DR LEILA JAHANGIRI DEPARTMENT OF PROSTHODONTICS AND BIOMATERIALS UMDNJ – NEW JERSEY DENTAL SCHOOL 110 BERGEN ST, ROOM D830 NEWARK, NJ 07103-1568 FAX: (973)972-0370 E-MAIL: [email protected] Copyright © 2002 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2002/$35.00 + 0. 10/1/121109
doi:10.1067/mpr.2002.121109
VOLUME 87 NUMBER 2