Dental Research

Color vision and dentistryWaletba Wasson* / Norman Schutnan"'"'

Color vision is a critical component of restorative and esthetic dentistry, but dentists,as a group, do not have their color vision tested at any time during their careers.A study was undertaken to ascertain the color-vision status of practicing dental person-nel at the University of Tennessee, College of Dentistry One hundred ftfty individuals,75 men and 75 women, were screened. The results corroborated the existing medicaldata for the general population. It was found that 9.3% of the men and none of thewomen exhibited eolor-vision defect. Since most dentists are male, this studydemonstrates an area of potential weakness for some practitioners. Once a color-visionproblem is found, it is simple to remedy by employing a team approach to shadematehing or mechanical means of matching shades (by the practitioner). No ethnic orracial distinctions were detected, although these have been reported in other studies.(Quintessence Int l992:23:.^49-353.)

Introduction

The ability of the dental practitioner to match colorsand shades correctly and consistently is a critical com-ponent of restorative dentistry, especially when anteriorrestorations are being prepared.' The color-matchingability of the dentist may involve training tn coloreducation and awareness of color-vision status. Anumber of authors have suggested that color-visionscreening for dental students and praetieing dentistsmight prevent negative experiences for both the patientand practitioner.'^*

Public demand for esthetic dentistry has markedlyincreased over the last decade because of the develop-ment of new esthetic products, simplified techniques,and increased patient-consumer awareness.'""" Chris-

Assistant Professor, Division ot Operative Dentistry, Lliiivcrsilyof Tennessee, Memphis, Coltege of Dentistry, 875 Union Avenue,Memphis, Tennessee 38163.Associate Professor, Division of Operative Dendstrv, tJniver-sity ofTeniicssee, Memptiis.

tensen, in iy87, reported that 92% of 5,000 dentistssurveyed in the United States indicated a significantinerease in esthetic dentistry procedures (ie, poreelainveneers, tooth-colored inlays and onlays, estheticcrowns, and bonding) as well as an emphasis by thepatient on improved appearance coupled with a willing-ness to pay the cost."' The increasing use of newtechnology in dentistry coupled with patient demandfor improved appearance should encourage the dentalstudent and practicing dentist to evaluate their color-matching skills.'"'•̂ •̂ "'•"" Many industries, such as trans-portation, commerce, electronics, and telecommunica-tions, use color-vision sereening routinely to detectcolor visual deficiencies in applicants,"'' ""

According to Preston." lhe "esthetic restorativedentist has the task of trying to ascertain and meet theexpectations of patients." The dentist's attempt tomeet the patient's needs and provide an acceptableoutcome can become a challenging task, depending onthe patient's perception of the need^̂ ""''' (ie, enhancebeauty'-^). If the dentist Is not cognizant of a color-vision defect (mild or moderate), he or she may believethat the patient's dissatisfaction is based on needs thatare difficult to meet, when, in fact, the dissatisfactionwith the interpretation of the tooth color may belegitimate. Therefore, the dentist becomes an essen-

Quintessence internafionai Voiume 23, Number 5/1992 349

Dental Research

tial player in the stimulus process of esthetic shadematehing;̂ '̂ (1) stimulus (light source); (2) object(tooth); (3) receptor (patient, dentist, staff); (4) inter-preter {patient, dentist, staff); (5) translator (dentist);and (6) performer (dentist or laboratory techni-

The light source must be appropriate for shadeselection. The spatial, optical, and biological proper-ties"" of the teeth are known to have a great effect onperception. These properties are important in thestimulus process and if ignored may cause negativerestorative outcomes. However, Seghi and others""'reported that "errors associated with color account fora significant portion of the variability that occurs inthe duplication process." Charbeneau'' stated that"from the patient's point of view, the selection of ashade for the conservative anterior esthetic restorationthat will match the color and translucency of the toothto be restored is probably the most important part ofthe appointment period." The focus is directed towardthe receptor eomponent of the stimulus process.

Individuals with color-vision defects cannot he ex-pected to discern matching colors in a manner compar-able with their color-normal cohorts.̂ "'•̂ •̂ •'••**'-''"""'̂However, dental practitioners (students or practicingdentists) should know their eolor-vision status. If acolor defect exists, the dentist should have staffcapable of assisting him or her in color discriminationand matching'^'''-'''^'''-''•'

Teeth are neither white nor pure yellow, as mostpeople who are not trained in the field of dentistrybelieve. They are not a monochromatic organ in theoral cavity, but are. instead, polychromatic with agradation of chroma from gingival margin to incisaiedge.''̂ '"*'̂ '''*''"*' There are subtle differences that occurin different degrees, varying angles, and portions ofthe teeth,''^ and these become a perpetual challengefor the clinician trying to address the esthetic concernsof the patient."" The basic color ratige of teeth, accord-ing to three studies, placed human teeth into the yellowto yellow-red hue ranges.''̂ ''"''''•*"""''" Individuals whosecolor-vision is red-green defective show a marked de-preciation in the yellow hue range {green-yellow toyellow-red) of the visible light spectrum.""

The male population has a greater propensity forcolor-vision anomalies than does the female."" ""*'Among a European, white population, 8% to 10% ofmales and 0.42% of females had a color anomaly.'" ""In 1963, Burnham and others^' reported that in theUnited States more than 10 million persons were esti-mated to have a red-green eolor-vision defect. In 1975,

Padgham and Saunders-''̂ reported that in the UniledKingdom, 8% of the male and 0.47o of the femalepopulation (2 million males and 100,000 females)have defective color vision. Most students enteringdental school are unaware of their color perception, ortnay be aware of only a slight deficiency that does notaffect normal daily visual acuity." Color screening isnot a part of the routine eye examination performed byan ophthalmologist or optometrist. Adams and Haeger-strom-Portnoy^'' suggested guidelines for eolor-visiotitestitig:

1. All children at an early age (before first grade)2. All patients on their first office visit (optometrist)3. All patients with an undiagnosed low visual acuity4. All patients who report recent color disturbances or

difference in eolor vision between the eyes

Many occupations require color-vision screeningprior to job placement. Verriest have classifiedcolor deficiency into three categories, of which"'occupations normally requiring normal color visionbtit in which instrumentation or the assistance ofcolleagues can help out with color problems'" appliesto dentistry.

Color is used as an aid in teaching the basic sciencelaboratory (histology, pathology, embryology) andclinical courses, as well as clinical procedures that relyheavily on color discrimination and matching.''""* If acolor anomaly is deteeted early in a dental student'scareer, the student (as well as students with normalcolor vision) ean be taught color principles and clinicalapplication in restorative procedures. In addition suchscreening would provide a base of information andguidance in teamwork building in the practice. Theteam approach includes using a staff member who hasnormal color vision to assist in color (shade) selection,which may prevent an unpleasant clinical experiencefor the patient and clinician.-'

Method and materials

One hundred fifty adult subjects, 75 men and 75women, were recruited for the study. Informed con-sent to participate in the study was obtained from allthe subjects. The study population included dentalstudents, dentists, dental hygienists, certified dentalassistants, faculty, and staff of the University of Ten-nessee, Memphis, College of Dentistry. Students fromthe Memphis Area Vocational and Technical Schooldental technologists, and denta! assistants, were also

350 Quintessence international Volume 23, er 5/1992

Dental Research

Fig 1 Male subjects identified witha color-vision anomaly.

8 0 -

6 0 -

ëi -10-<

20 -

0 "

mII)

^ ^ 1Í

Iil m

I - .

1 2 3 4 5

Males with mlor^uisinn defect

aiul

i i!

6 7

• AgsQ Screening plates

included. Exclusion criteria consisted of participantswho wore tinted lenses."" Tinted lenses "alter the spec-tral properties of the stimuli confounding interpretationsof the test restilts."^^

The Standard Pseudoisochrom a tic Plates-Congenital(SPP-C). Part One-Congenital Color Vision Defects(Klingaman R: Personal communication, 1990). wasused to detect hereditary col or-vision defects(CVDs).̂ - '̂̂ '̂ '̂-'-"-'* Congenital CVDs were examined,sirtce they have a "stationary nature, present at birtb,and usually affect both eyes equally.'"^^Tbe SPP-C is a"good test to screen color normals from individualswith any hereditary red-green defects (mild, moderate,severe)."^^ Tbe SPP-C is constructed from uniform-sized dots found on electronically generated numericdisplays (eg, pocket calculators).•'̂ -'••̂ '' The pseudoiso-chromatic test is the most extensively used test, be-cause it is inexpensive, quick, and easy to use.^''Thescreening test is used in manufacturing, transporta-tion, electronics, telecommunications, vocational guid-ance, military induction and screening, psychophysi-cal and genetic research, and even elementary school

sett ¡tigs. Each subject viewed nineteen colorplates. The screener answered any questions to permitoptimal concentration on the color plates. ATrue Day-light color book stand and illuminator (Richman, fnc)was used to ensure comparability between subjects.

Results

One bundred fifty persons took the SPP-C test forcolor vision. All female subjects tested normal for

color vision. Seven male subjects (9.3%) exbibiteda color-vision defect, demonstrating tbe sex-linked na-ture of this condition (Fig 1). With regard to race oftbe subjects, no link was evident. However, studieswith larger sample poptilations bave noted that tbeincidence of color-vision defect varies among variousethnic and regional groups.""'̂ ' ''' Of tbe seven subjectswbo tested positive, six were white, while one was na-tive American and white (Fig 2). Of those who testednormal, the raciai makeup was as follows; 43 black,95 white, and five Asian. Color-vision defect was alsodemonstrated to have no relationship with age. Tbeage range of those testing positive was 23 to 67 years.The age range of subjects testing normal was 19 to 66years.

Discussion

This study corroborated results of past studies.̂ •''•'"••̂ •̂•̂ "Color-vision defect was exclusively a male problemoccuring in seven (9.3%) of 75 male subjects. Nowomen tested positive, as might bave been expected,because the prevalence of color defect in women is ap-proximately 0.4%. Since most dentists are men, how-ever, it is necessary to concentrate on the male resuits.

With regard to racial difference, the results wereinconclusive. No black subjects tested positive. Thesame result occurred among Asian subjects. Amongwhites, abotit 10% of men tested positive. The singlenative American and white subject also tested positive.The sample size was large enough to mirror the male-female relationships as they exist in tbe general popu-

Ouintessence International Volume 23, Number 5/1992 351

Dentai Researcin

-Survey populalion

-Reference populations

Fig 2 Differences in color-visiondefects among survey and refer-ence popuiations: (AA) AfricanAmerican; (WE) white European; (A)Asian; (C) Canadian; (NW) nativeAmerican/wbite.

lation. Individual racial distinctions, which have beenreported previously, could not be duphcated In thisstudy.

Three alternative tracks exist for the individual withcolor-vision defect: (}) a formal course or courses incoior edueation and training for dentists and dental as-sistants, (2) the development of a staff trained in eolormatehing and discrimination of teeth shades, and (3)development of coiorimetric instruments" '̂"*""'' thatdiscern small and subtle eolor differences, includingthe properties of fluorescence and translucence ofteeth (which are just noticeable for tbe color-vision-normal practitioner, who may vary from day to daywith color perception, and for the color-vision-defec-tive individual wbo may have abnormalities in the red,blue, or green areas). The alternative tracks are ad-junctive measures that will provide a cohesive clinicalpractice environment for the dental clinician, especiallythose requiring assistance In esthetic sbade matching.

Conclusion

Heretofore, tbe technology was not available, but thedevelopment and improvement of estbetic materialsand techniques have provided the patient-consumerand dentist with restorative materials and techniquesto address their estbetic concerns in shade matching.

The integral part color plays in human vision, par-ticularly in color matching of dental restorative mate-rials for the human dentition, is of tantamount con-cern for tbe dentist, A review of the literature revealedthat the eyes are tbe weak link in esthetic shade

matching, A significant percentage of dentists and den-tal students experience color-vision defect (from mildto severe). Among white men, the prevalence ap-proaches 10%, At the present time, few options existto assist dentists who are color-vision defective. If thealternative tracks are explored further and research isdeveloped, products may be developed that will help thedental community to address some of the color-visionproblems assoeiated with esthetic shade matching,

Acknowledg ments

The authors would like to Ihank Dr Roger Klingaman, AssisLamProfessor at the Southern College of Optomclry. for his consultativesupport on this projeci. This study was approved by the fnslitu-tional Review Board at the University of Tennessee, Memphis,

1, Sproull RC: Color matching in dentistry. Part 111, Color con-trol. J Prosihei Dent I974;3I:146-154,

2, Barna GJ, et al: The influence of selected light intensities oneolor perception with color range of natural leelh, J ProsihetDem lyt(l:46:45Ü-453,

3, Preston JD: Color in dental ceramics, in Schärer P, Rinn LA,Kopp FR (eds): E.^ihetic Guidelines for Restorative Dentistry,Koehler HM (Irans). Chicago, Quintessence Publ Co, 1982.pp t3-25,

4, Moser JB, et al: Color vision in dentistry: a survey J Am DentA.tsoc 19R5;ttn:5O9-5tO.

5, Insights to Esthetie Dentistry. 1989, Savannah, Ga, BrasselerUSA, Inc, 1988, pp 1-12.

Ö. Lemire PA, Burk B: Color in Dentislry. Hartford Conn JMNeyCo, 1975,

352 Quintessence International Volume 23. Number '

Dental Research

, 28.

• 29.

30.

Larson TDi Toftiniquo for achieving realistic color distritju-tion in large composite rosin restorations. .1 Am Dem Assoe1987;(special issue]:26E-40E.

Fergenbaum N. Mopper KW: A Complete Guide to DenialBonding. East Windsor, NJ, Johnson & Jahnsun Dental CareCo, WS4.

Ramfjord SP: Dentistry in the 21st century. Quintessence tnlt989l20:t67-t7t.

Williams HA, Caughman WF: Principles of esthetic dentistry:praetieal guidelines for ttie practitioner, in Hardin JF (ed):dark's Ciinicat Dentistry, vol 4. Pti i lade! phi a, JB Lippincott Co,1989, pp 1-2Ü.

Sheets CG: tvlodern dentistry and the esthetically awarepalient. J>lin DentAssoe I987:(speciat issue): 103E-t05E.Hunt PR: The future ot esthetic dentistry. J Am Dent Assoe1987.(speciat issue): 106E-lt2E.Faunce F: Esthetic dentistry: a new direction. / Am DentAssoc 1987;(speciat issue):5E.

Phillips RW: Eras of new biomaterials in esthetic dentistry.J Am DentAssoe 1987;(speciat issue).7E-12E.

Christensen GJ: Tooth-colored inlays and ontays. J Am DenlAssoc 1987;(spedal issue):t2E-t7E.

Weinstein AR: Anterior composite resins and veneers: treui-ment planning, preparation, and finishing. J Am Dem As¡oet988;(special issue):38E^5E.

Jordan RE: Estiietic Composite Bonding: Techniques and Male-riais. Philadelphia, BC Decker. 1988.Garber DA. Goldstein RE, Feinman RA: Poreetain LaminateVeneers. Chicago, Quintessence Publ Co. t988.

Goldstein RE: Change Your Smile, cd 2. Chicago, QuintessencePubtCo. t988.BrightbitlT: Cosmetic dentistry./1GD/ii/'orit989;17(lt): 10-13.

Charbeneau GT: Direct esthetic restorations, in CharbencauGT (ed): Principies and Practice of Operative Dentistry, ed3. Phitadetphia, Lea & Febiger, 1988, pp 267-272.Freedman GA, McLaughhn GL: Color and the porcelain lami-nate, in Hacke G (ed): Color Alias of Porcelain Laminate Ve-neers. SI Louis, tshiyaku Euro America, 1990, pp 135-137.The promising future of dentistry. A report. Six clinicians dis-cuss the future of dentistry. Deni Management 1987;Jan.Preston JD, Bergen SF: Color Science and Dental Art: A Self-Teaching Program. St Louis, CV Mosby Co, 1980.Freedman GA, McLaughlin GL: The demand for cosmeticdentistry, in Hacke G (ed): Color Atlas of Porcelain LaminateVeneers. St Louis, Ishiyaku Euro America, 1990. pp 1-6.Birch J: A practical guide for colour-vision examination. Reportof the standardization committee of the international researchgroup on colour-vision deficiency. Ophthalmic Physioi Opi 1985:5.265-285.

Verriest G: Vocational and practical implications of defectivecotor vision, in Pokorny J, Smith VC, Verriest G, et al (eds):Congenitai and Acquired Color Vision Defect. New York, Grureand Stratlon, 1979, pp .349-357.Swanson WH: Color vision: assessment and clinical relevance.Ophihaimic din Norlh Am 1989;2:3yi^l3.Adams AJ, Haegersttom-Portnoy G: Color deficiency, inXm¡:i5 ]¥ (e:á). Diagnosis and Management in Vision Care. Stone-ham, Mass, Butterworths, t9g7, pp 671-711.Coren S, Hakstian AR: Color vision without the use of techni-cal equipment: scale developtnent and cross-validation. Per-eeption Psychophysics 1988;43:115-120.

Aarnisalo E: Testing of eolor vision for vocational purposes.Acta Opthamol ¡Supplj (Copenh) 19a4;161:135-13S.

32. Preston JD: Current status of shade selection and color match-ing. Quintessence Inl 1985; 16:47-58.

33. Neumann L, et al: Dental esthetic satisfaction in adults. J AmDentAssoe t989;tt8:565-57O.

34. Goldstein RE: Esttietics in Denlislry. Phiiadeiphia, JB Lippin-cott Co, 1976, pp3-16.

35. Nasti DA: Professional ethics and esthetic dentistry. J Am DentAssoc I988;(specia[ issue):7E~9E.

36. Swepston JH, Miller AW: Esthetic matching. J Proslhet Dem1985:54:623-625.

37. Clark EB: Tooth color selection. J Am Dent Assoc 1933:20:1065-1073.

38. Saleski CG: Color, tight, and shade matching. ] Pro.iihel Denl1972;72:263-268.

39. Preston J: The elements of esthetics — application ot colorscience, in McLean JW (ed): Déniai Ceramics: Proceedings ofthe First International Symposium on Ceramics. Chicago, Quin-tessence Publ Co, t983, pp 491-520.

40. Seghi RR, et al: Visual and instrumental colorimetric assess-ments of small coior differences on translucent dental porce-lain. J Dent Res 1989 ;68:1760-1764.

41. Pokorny J, et al: Congenital color defects, in Pokomy J, SmithVC, Verriest G. ct al {eds): Congenilai and Acquired CoiorVision Defect. New York. Grune and Siratton, 1979, pp 183-241.

42. Davison SP, Myslinski NR: Shade selection by color vision-defective dental personnel. J Prosthet Dent 1990;63:97-101.

43. Milter L: Organizing color in dentistry. ,//lm Dem Assoe 1987;(special issue ):26E-4ÜE.

44. Matthews TG: A method for shade selection. IL Quinlesseneetm 1980;ll(3):67-7(l.

45. Matthews TG: A method for shade selection. 1. Quinlessence Int!980;ll(2): 101-105.

46. Goldstein RE: Esthetics in Dentistry. Philadelphia, JB Lippin-cott Co, 1976, pp 79-81.

47. Sproult RC: Understanding color, in Goldstein RE: Esthetics inDentistry. Philadelphia. JB Lippincott Co, 1976, pp 404-410.

4S. SprouU RS: Color matching in dentistry. Part 11. Practical appli-cations of the organization of color. J Ptostiiel Dem 1973;29:556-566.

49. Clark BE: An analysis of tooth color. J Am Dem Assoc 1931:2093-2103.

50. Best D: Hue, value, and chrotna: Dental color terminology andthe world of art. Trends Technique Conlemporv Dent Lab 1984:1(5):31-34.

51. Buinham RW, et al: Color: A Guide to Pads and Concepls. NewYork, John Wiley and Sons, 1%3, p 103.

52. Padgham CA, Saunders JE: The Perception of Light ond Colour.London, G Bell and Sons Ltd. 1975, p 154.

53. Ichikawa H, Hukami K, Tanabe S, et al: Standard Pseudoiso-chromatic Plates. Par! One. For Congenital Color Vision Defecis.New York, Igaku-Shoin, 1978.

54. Honson VJ, Dain SJ: Performance of the standard pseudoiso-chromatic plate test. Am J Opiom Physio! Opt 1988;65:561-570.

55. Long GM. et al: Color vision screening and viewing conditions:The problem of misdiagnosis. Nurs Res 1985;35{1):52-.S5.

56. Birch J, et al: Clinical testing methods, in Pokorny J, Smith VC,Verriest G, et al (eds): Congenital and Acquired Color VisionDefect. New York, Grune and Stratton, 1979, p 90.

57. Seghi RR, et al: Pcrformanee assessment of cotorinietric dcviœson dental porcelains. J Dem Res 1989,68; 1755-1759. D

Quintessence Internationai Voiume 23, Number 5/1992 353