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9 d1075 v_n_v_madhav

  1. 1. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhav ESTHETIC FAILURES IN FIXED PARTIAL DENTURES V N V Madhav1* 1. Dr, M.D.S. (Prosthodontics), Reader, Department of Prosthodontics, Bharati Vidyapeeth Dental College and Hospital, Pune, India. Abstract Esthetic dentistry encompasses those procedures designed to enhance and improve form and appearance of the maxillofacial region. Esthetic dentistry procedures are performed on both hard and soft tissue to correct either subjectively or objectively, patient perceived deformities. Perceptions of esthetic deformities or needs are highly subjective. In this article an effort has been made to outline the possible esthetic errors which occur in the absence of careful treatment planning during the fabrication of fixed partial denture procedure. (J Int Dent Med Res 2010; 3: (3), pp. 146-153 ) Keywords: Esthetic Failures, Shade Selection, Gingival Esthetics, Esthetic Smile. Received date: 19 July 2010 Accept date: 21 September 2010 Introduction along with need for dedicated maintenance. The proper selection of treatment occurs through a The surge of interest in the use of tooth- comprehensive dialogue between thecolored restorative materials and systems in Prosthodontist and the patient in which bothrecent years has been attributed partly to rapid subjective and objective evaluations are utilizeddevelopments in dental materials science and to determine appropriateness of treatment andalso to patient demand and operator interest. thus enable the assumption; of reasonable risk / When overall dental appearance is benefit ratio. The irreversibility of many estheticsconsidered, several factors are of significance, procedures requires that the patient be fullyincluding tooth color, shape, and position; aware of future additional and / or alternativerestoration quality; and the general arrangement treatments if their initial esthetic goals are notof the dentition, especially of the anterior teeth. met. In this article an effort has been made toEach factor may be considered individually, but outline the possible esthetic errors which occur inall components together act in concert to produce the absence of careful treatment planning duringthe final esthetic effect. However, although the the fabrication of fixed partial denture procedure.clinician must be mindful of the patients desiresfor a favorable cosmetic result, materials and Evolution of Ceramics as an Esthetictechniques must be carefully selected, and Alternativerestorations should be sufficient to withstand the The metal-ceramic crown was introduced to theforces of occlusion and mastication and provide profession over four decades ago. At the timelong-term function and esthetics1. there was tremendous excitement generated by The elective nature of esthetic procedures the concept because it theoretically combined therequires that the patient is thoroughly educated esthetics of the porcelain jacket crown with theabout possible risks and adverse consequences potential for clinical longevity2. However, it is likely safe to state that most clinicians were somewhat disappointed by the *Corresponding author: Dr. V.N.V.Madhav, M.D.S. (Prosthodontics) initial clinical results obtained with this treatment Reader, Department of Prosthodontics, modality. It is highly likely that most early esthetic Bharati Vidyapeeth Dental College and Hospital, failures with metal-ceramic restorations were due Pune . to a combination of errors in tooth preparation, cervical margin design and soft-tissue E-mail: vnvmadhav@yahoo.co.in management. Nevertheless, the disappointment with metal-ceramic restorations was the genesis Volume 3 · Number · 3 · 2010 Page 146
  2. 2. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhavfor the development of numerous all-ceramic  Midline erroralternatives to the metal-ceramic restoration. The  Imbalance of directionspast two decades has witnessed the  Artifact errorunprecedented introduction of alternatives to the  Diastema errormetal ceramic crown 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16. In addition, many different techniques for Factors Affecting Esthetic Failuresfabrication of all-porcelain labial margins have One of the goals of any dental restorationbeen developed to improve the inherent esthetic should be patient satisfaction. The restorationperformance of metal-ceramic restorations 17, 18, 19, should fulfill the requirements of correct20, 21, 22 . In clinical situations with sufficient mastication function, appropriate morphology,remaining enamel, etched porcelain laminate superficial staining, abrasion and otherveneers may also be considered to restore the characterization. Finally, the shade selectedteeth to both optimum esthetics and function 23, 24, must correspond to the individual, age related25, 26 . appearance of the patient and should be identical Thus, the contemporary host of indirect to the remaining natural teeth. Problems thatalternatives for the esthetic restoration of anterior arise during fabrication can be overcome in spiteteeth. It is also clear that ceramic technology has of the difficulty level, which varies from case tomatured to the point that it is possible to mimic case and depends in part on whether thenature and provide restorations that defy restoration involves a single crown or a fixeddetection to even the trained observer. partial denture. A general requirement for the success of laboratory work by the dentist (i.e.; Classification of Esthetic Errors27; proper shade selection, correct tooth preparation(Richard E. Lombardi; 1974) and final impression).I. Inharmonious dento-facial ratio 1. Shade disharmony Tooth Shape 2. Compositional incompatibility The facial surface of the tooth is a part of  Static prosthesis in dynamic mouth tooth form. It is decisive in shaping tooths  Inharmonious strength or weakness of appearance, particularly when severe changes dental composition compared to occur in old age. The incisal edge, which may be background features. slightly convex in shape initially, changes as well. a. Weak mouth with strong face. As a consequence of abrasion it may b. Strong mouth with weak face. eventually become concave. All of these variableII. Intrinsic dental disharmony characteristics of tooth shape combine to 1. Space allocation errors determine the effect of the tooth in the mouth, to  Inadequate vertical space allocation a significantly greater degree than does the  Excessive vertical space allocation shade. The changes in the cervical region,  Excessive horizontal space allocation through gingival recession for example, also lead 2. Structural line errors to an appearance typical of a certain age. These  Elevated occlusal plane changes have a more pronounced effect on the  Occlusal plane drops down posteriorly appearance of the dental arch than on the shade.  Asymmetrical occlusal plane Because the gingiva usually recedes 3. Unnatural lines inter-proximally as well, it leaves the crown of the  Reverse smiling line tooth with a more triangular appearance. If these  Unnatural axial inclination teeth are replaced by a restoration having a  Cusp less posterior teeth square form, they will appear more unnatural. It is expected that the form of the clinical crown  Gradation errors correspond to the course of the root, which is  Age-sex personality disharmony often exposed because of periodontal disease. 4. Single-line errors  Vertical deviation Surface Structure and  Horizontal deviation Characterizations  Line conflict The natural surface detail is most 5. Imbalance extensive in a young tooth. Many fine, detailed Volume 3 · Number · 3 · 2010 Page 147
  3. 3. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhavirregularities occur, particularly on the labial To these three dimensions, and within thesurface. At the first glance one sees horizontal field of dentistry, we must add a fourth one whichdepressions. Vertical lines become visible with would include all of the chromatic features thatmore careful observation, so that a pattern of personalize the tooth apart from its averagevery fine, slightly displaced rectangles is seen. color, and which are fundamental for the repro- The older a tooth becomes, the less duction of the color of a tooth.prominent these structure become. Millions of lipmovements in the same direction lead to Gingival Estheticsformation of large smoothed regions between Factors Affecting Gingival Esthetics:which few structured zones are retained. Enamel The morphology and dimension of supracrestaltears, abrasions, discoloration, incisal edge periodontal tissues undoubtedly represent theirregularities, bright spots, and band-shaped most important parameters to be taken intoshade variations are not the only consideration in designing a fixed prosthesis28.characterizations that must be evaluated. Cervical erosions and fine lines that The Esthetic Width; As the supracrestalseparate the clinical crown and the root, which connective tissue attachment is resected duringmay result from simple aging or from oral tooth preparation, so should the esthetic width behygiene procedures, must also be evaluated. respected when designing the prosthetic framework, a distinct space is necessary Color between the coronal border of the gingiva and Nature of Color: When we talk about the cervical margin of the framework to providecolor, we are making reference to a sensation adequate room for the application of specificwhich is captured by our eyes. The human eye is shoulder porcelain.an organ specialized in the reception of imagesobtained from an electromagnetic radiation that The Umbrella Effect; A careful analysis ofwe refer to as light, and which actually clinically relevant optical phenomena shouldcorresponds to a narrow segment of the entire always include the effect produced by the lips,spectrum, situated between the 400 and 800 nm particularly the upper lip, because this feature willwavelengths approximately, and which we significantly influence the interaction of light withperceive as the so-called “colors of the rainbow”. the teeth and their supporting tissues. When the Radiations below these wavelengths are lips are retracted, the apical extension of thenot visible to the human eye, and are referred to framework generally will not have a strong impactas ultraviolet; those which are situated above on the optical behavior of the crown, because thethese wavelengths are not visible either, and are light can be directly distributed into the tissues.referred to as infrared. When the upper lip is in its normal There are generally three accepted position, however, the difference becomesdimensions of color: significant, because direct penetration of light into Hue, tonality: this indicates the feature which the surrounding periodontal tissues is prevented. is normally referred to as color, directly related In contrast, an adequately reduced framework to the wavelength of the observed luminous does not demonstrate the so-called umbrella radiation observed (e.g. red, green, blue, effect. yellow…). Value, luminosity: this expresses the amount Esthetic Smile of light that makes up the color under study, The smile is expressed by muscular and would be like the black and white image action around the lips in the inferior third of the of the observed object, corresponding to the face by a brightening of the eyes. The pleasing tonalities of grey ranging from a maximum smile is one of our special forms of nonverbal value, white, and a minimum value, black. communication, and it expresses joy. Chroma, saturation: this refers to the amount of dye that the color contains, the chromatic The elements that effect in an esthetic brightness that we observe. This dimension smile are; refers to the different dilutions of the base  The upper lip position color we are starting from.  The upper lip curvature Volume 3 · Number · 3 · 2010 Page 148
  4. 4. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhav The parallelism of the anterior incisal curve The property of light source to influence color of with the lower lip objects is called “color rendition”. There are three The relationship between the maxillary main illuminants within any dental practice: anterior teeth natural, incandescent and fluorescent. The number of teeth displayed in a smile Natural sunlight is itself variable with light appearing blue at noon when the sun has fewer The most attractive smiles have nearly atmospheres to penetrate and red/orange duringperfect harmony between the arcs of curvature of the morning and evening. Incandescent lightingthe incisal edges of the maxillary incisor and the is predominantly red/yellow and lacking in blueupper border of the lower lip, and the upper lip while fluorescent lighting is high in blue tonescan be at the height of the gingival margin of the and low in red. There are special that aremaxillary central incisor. It was found that in an color corrected to emit light with a more uniformattractive smile, the full shape of the maxillary distribution of color that can be utilized. Initialanterior teeth was displayed between the upper shade selection should be initially made with beand power lip. The upper lip curved upward or matched under different lights to avoidwas straight, the maxillary anterior incisal curve metamerism (the phenomenon that occurs whenwas parallel to the lower lip, and the teeth were shades appear to match under one lightingdisplayed to the first molar. condition and not another). SHADE SELECTION FAILURES Factors Affecting Light Conditions To date, there is no systematic training on  Gingival shadevisual shade determination 29, 30, 31 for dental  Influence of the surroundingstechnicians or dentists32. Therefore; all attempts  Type and arrangement of the shade guideto improve the color communication fail at this  Position of the shade tabbarrier.  Different color perception capacities The many difficulties associated with  Knowledge about color and its perceptionvisual shade determination of manufactured or  Experience in shade selectioncustomized shade tabs for natural teeth are  Acting mechanism of the eye (simultaneousfurther complicated by the fact that color contrast, contrast increase)interpretation by the human eye is influenced bya variety of factors. When determining a color, the human eye Shade selection is an important perceives a certain shade; however, underprocedure to provide patients with an aesthetic modified light conditions, the color perceptionrestoration that harmoniously blends to the and the subsequent shade selection can bepatient’s existing dentition. Knowledge of the completely different. This implies that whenscientific basis of color from understanding light shade guides are used exclusively, the toothto also interpreting the artistic aspects of shade shade required is always described in anselection ensures a successful result. Shade insufficient manner33-35.selection involves the perception of color, which It is important to use auxiliary tools and adepends on three entities: shade indicator that is arranged according to a 1. Light logical system oriented by the natural model 2. Object; and 3. Visual detection Object The visual system of the eye is only Color possesses three dimensions: value,capable of detecting wavelengths from 380 hue and chroma. A high value object often(violet) to 780nm (red). Isaac Newton showed reflects most of the light falling on its surface andthat light had no color, as it is only when it appears bright. The converse is true with a darkinteracts with an object that color is produced. object absorbing most of the light and appearing dull or of low value. Hue is wavelength of light, Light and dependent on the spectral reflectance from The color of an object can change an object. Chroma is the concentration of color ordepending on the illuminant, e.g. tungsten light color intensitymay cast a yellow color compared to daylight. Volume 3 · Number · 3 · 2010 Page 149
  5. 5. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhav Visual detection preparation as teeth can become dehydrated The third part of stimulus for color is the and result in higher values.spectral response of the detector, or eye. The  Shades should be done when the dental teamdifficulty of shade selection is that clinicians must is not fatigued as in the end of the day.be able to interpret a multi-layered structure of  Ensure surgery surroundings are of neutralvarying thickness, opacities and optical surface color so that there is no color cast onto thecharacteristics. This can affect the way that the teeth.eye perceives color. The basic hue of the tooth is  Remove lipstick; ask patients not to wear luriddetermined by the color of the underlying dentine, clothing or any items that may distract thewhile value is a quality of the enamel overlay. attention of the teeth. Muia in 1993 stated, “The dentine imparts  Make sure teeth are clean and unstainedthe entire color. Enamel is like a fiberoptic before attempting shade selection.structure conducting light through its rods”.  Patient should be in an upright position at a Chroma is the saturation of color in the level similar to the operator and the shadedentine, but is influenced by the value and guide should be at arms length. This ensuresthickness of the enamel. Teeth are often termed that the most color sensitive part of the retina“polychromatic” and have the variation in hue, will be used.value and chroma within the teeth and give three  Observations should be made quickly (5dimensional depth and characteristics. A young seconds) to avoid fatiguing the cones of thedentition is characterized by opaque, high value eyes. If longer than this, the eye cannotenamel, which blocks underlying dentine. As discriminate and the cones become sensitizedteeth age, the enamel becomes more translucent to complement the observed color.and dull (low value) revealing the underlying  Blue fatigue can accentuate yellow sensitivitydentine. This layering can make reading of tooth so dentists can look at a blue object, bib, etc,color difficult since the value of enamel and while resting the eyes.surface luster often complicate color evaluation  Use color corrected light illumination, whichof the underlying dentine. should be of a diffuse nature.  Choose basic shade at the middle of the tooth Contrast Effect - using the Vita System 3D-Master technique When a dental restoration is being of value, chroma then hue. Viewing tabsfabricated, the surroundings of the teeth, through half-closed eyes can decrease abilityespecially the shade of the gingival tissues, are to discriminate color but increases the abilitydecisive for the color integration of the restoration. to match value. Look at the other parts of theWith the conventional visual shade determination, teeth, dividing the teeth into nine sectionsso-called simultaneous contrast effects and from apical to incisal and mesial to distal.contrast increases occur 36, 37, 38. To explain briefly: Shade selection is  Necks of shade tabs often can be removed asperformed in a reddish environment-skin, lips, they have a great deal of colorants that mayand gingival tissues. This environment, and introduce errors.especially the reddish-violet color of the gingival  Examine tooth for translucency and anytissues, leads to a marked decrease in the characterizations, e.g. craze line,receptiveness of this area to the color spectrum hyopcalcification, etc.The brain replaces the apparent excess of red  Create a shade/chromatic map – divided intowith the complementary shades green to yellow. different sections to ensure correct placement This leads to a subjectively modified color of different effects, characterizations andperception, which expresses itself in a tendency shades.toward seemingly objective yellowish shades.  In case of color blindness, seek the help of theThis contrasting effect can be neutralized by the assistantuse of a gingival mask.  Shade selection is done before tooth preparation Tips to Remember During Shade  Dont dry the tooth while selecting the shadeSelection Procedure  Moisten the shade tab  Shade selection should be completed before  Canine is the darkest tooth Volume 3 · Number · 3 · 2010 Page 150
  6. 6. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhav  Premolars are of lighter shade than canine failure, and thus increase the quality of  For premolar select contra-lateral premolar restorations.  When maxillary anteriors are missing, shade of the mandibular anteriors are considered  In case of a non-vital tooth, cover it and select the shade of the adjacent tooth.  Photograph teeth and tabs using different lighting conditions to minimize metamerism, e.g. flash (5500K) and natural daylight (6500K). Table 1. Commercially Available Digital Shade  Photograph teeth at 1:1 ratio for detailed Guides. characterizations.  Send digitized images and shade map to As a summary reasons for esthetic ceramist. failures can be summarized as following.  Failure to identify patient expectations Stump shade selection regarding esthetics With the increasing use of all-ceramic  Improper shade selectionrestorations, it is important to communicate the  Failure to transfer the shade to dentalprepared tooth or “stump” shade to the ceramist laboratoryso that they can build the restoration with the  Excessive metal thickness at incisal andright opacity/translucency. It may be necessary cervical regionas in to use a more opaque ceramic to block out  Thick opaque layer applicationdiscoloration, e.g. an alumina- or zirconia based  Surface blistering ("chalky" appearance)restoration may be a better choice than a glass-based ceramic like Empress.  Over glazing or too much smooth surface Although no single shade guide or  Metal exposure in connector, cervical andcombination of guides includes all of the color incisal regionscombinations that may be encountered in clinical  Dark space in cervical third due to improperpractice, a reasonably high level of clinical color pontic selection (Anteriors)matching has been achieved, which attests to the  Failure to produce incisal and proximalartistic skills of many dentists in selecting the translucencybest available shade and determining what color  Improper contouringmodifications are necessary to further enhance  Failure to harmonize contra-lateral tooththe color match. morphology 1. Contour Instrumental Shade Selection 2. Color Given the great subjectivity that 3. Positionpredominates all during the color measurement 4. Angulationsprocess in the clinic, a series of electronic  Discoloration of facinginstruments designed to facilitate and make moreobjective the process of color measurement have The contemporary restorative dentist hasrecently been appearing on the market. The a host of options with which to help his or herpractitioner thus needs only to use these devices patients are treated. Many of these options arein order to be able to indicate the tooth’s color in considerably less invasive than many of oura more precise, reliable and repeatable way. conventional restorative therapies. Many patients Knowledge of the correct use of the present for esthetic restorative treatment, and areconventional color measurement systems is becoming increasingly sophisticated in theirbecoming more and more important if we wish to expectations of the final results. Additionally,satisfy present day esthetic demands. manufacturers are bringing a myriad of new This, together with the gradual entry and products to the market, often accompanied by aperfection of the electronic color meter systems, blizzard of information purported to demonstratewill serve to reduce the possibilities of aesthetic the benefits and efficacy of these new products. Volume 3 · Number · 3 · 2010 Page 151
  7. 7. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.MadhavCareful evaluation of patient’s expectations and 6. Cho GC, Donovan TE, Chee WWL. Rational use of contemporary all-ceramic crown systems. J Calif Dent Assoc 1998: 26: 113–needs and proper choice of materials and 120.techniques along with sound knowledge and skill 7. Donovan TE. Contemporary ceramic restorations: a comparativeof the operator can decrease the failures in the evaluation. Alpha Omegan 1988: 81: 57–64. 8. Lehner C, Studer S, Brodbeck U, Scharer P. Short-term results ofesthetic outcomes in fixed partial dentures. IPS-Empress full-porcelain crowns. J Prosthodont 1997: 6: 20– 30. 9. Malament KA. Considerations in posterior glass-ceramic Conclusions restorations. Int J Periodontics Restorative Dent 1988: 8: 32–49. 10. McLean JW. New dental ceramics and esthetics. J Esthet Dent Today’s dental restoration is consolidated 1995: 7: 141–149. 11. Probster L. Four-year clinical study of glass-infiltrated, sinteredaround three mainstays: the use of non- metallic alumina crowns. J Oral Rehabil 1996: 23: 147–151.materials, such as composite resins and 12. Rinke S, Huls A. Copy-milled aluminous core ceramic crowns: a clinical report. J Prosthet Dent 1996: 76: 343–346.ceramics; adhesion to dental structures; and the 13. Sorensen JA, Choi C, Fanuscu MI, Mito WT. IPS Empressachievement of a natural cosmetic look. The level Crown system: three-year clinical trial results. J Calif Dentof esthetic requirement and demand by patients Assoc 1998: 26: 130–136. 14. Sozio RB, Riley EJ. The shrink-free ceramic crown. J Prosthetin restorations has risen spectacularly in recent Dent 1983: 49: 182–187.years, and this has made it necessary for dental 15. Wohlwend A, Scharer P. The Empress technique: a newprofessionals to explore this field in order to technique for the fabrication of full ceramic crowns, inlays, and veneers. Quintessence Int 1990: 16: 966–978.satisfy the existing social demand in this area. 16. Wohlwend A, Strub JR, Scharer P. Metal-ceramic and all The dental materials that are available porcelain restorations: current considerations. Int J Prosthodontnowadays offer us the possibility of imitating the 1989: 2: 13–26. 17. Donovan TE, Adishian S, Prince J. The platinum bonded crown:tooth’s natural esthetic look, so long as the right a simplified technique. J Prosthet Dent 1984: 51: 273–275.one is chosen for a given situation. The first step 18. Kessler JC, Brooks TD, Keenan MP. The direct lift-off technique for constructing porcelain margins. Quintessence Dent Technolto achieving clinical success in esthetic dentistry 1986: 10: 145–150.will therefore be to correctly identify the patient’s 19. Prince J, Donovan TE. The esthetic metal-ceramic margin: Aneeds and to imitate tooth color with the material comparison of techniques. J Prosthet Dent 1983: 50: 185–192. 20. Prince J, Donovan TE, Presswood RG. The all-porcelain labialthat most closely matches, and to communicate margin for metal-ceramic restorations: a new concept. Jthis information to the laboratory if the restoration Prosthet Dent 1983: 50: 793–806. 21. Toogood GD, Archibald JF. Technique for establishingis to be carried out there. porcelain margins. J Prosthet Dent 1978: 40: 464–466. Color measurement may seem to be a 22. Vryonis P. A simplified approach to the complete porcelainminor element within the field of Restorative margin. J Prosthet Dent 1979: 42: 592–593. 23. Cho GC, Donovan TE, Chee WWL. Clinical experiences withDentistry, but its importance is essential, bonded porcelain laminate veneers. J Calif Dent Assoc 1998:although not from the biological point of view. But 26: 121–127.given the present day level of esthetic exigency, 24. Friedman MJ. The enamel-ceramic alternative: porcelain veneers vs. metal-ceramic crowns. J Calif Dent Assoc 1992: 20:a technically correct restoration can be a clinical 27–33.failure if it fails to achieve the esthetic integration 25. Horn HR. Porcelain laminate veneers bonded to etchedthe patient nowadays demands. enamel. Dent Clin North Am 1983: 27: 671–684. 26. Materdomini D, Friedman MJ. The contact lens effect enhancing porcelain veneer esthetics. J Esthet Dent 1995: 7: Declaration of Interest 99–103. 27. Lombardi Richard E: a method for classification of errors in dental esthetics. J Prosthet dent. 1974; 32: 501-513. The authors report no conflict of interest 28. Malament Kenneth A: Periodontics and Prosthodontics. Goalsand the article is not funded or supported by any and objectives and clinical reality. J Prosthet dent. 1992; 67: 259-263.research grant. 29. Egger B. Der Status quo der Ästhetik. Quintessenz Zahntech 1997; 23:191–204. 30. Preston JD. Der gegenwärtige Entwicklungsstand der References Farbbestimmung und Farbanpassung. Part I. Quintessenz Zahntech 1985; 11:863–873.1. Qualtrough AJ, Burke FJ, A look at dental esthetics, 31. Preston JD. Der gegenwärtige Entwicklungsstand der Quintessence Int. 1994 Jan; 25(1):7-14. Farbbestimmung und Farbanpassung. Part II. Quintessenz2. Jones DW. Development of dental ceramics. An historical Zahntech 1985; 11:957–965. perspective. Dent Clin North Am 1985: 29: 621–644. 32. Clark BE. The color problem in dentistry. Dent Digest 1931:8.3. Adair PJ, Grossman DG. The castable ceramic crown. Int J 33. Miller L. A scientific approach to shade matching. In: Preston Periodontics Restorative Dent 1984: 4: 32–46. JD. Perspectives in Dental Ceramics. Proceedings of the Fourth4. Andersson M, Oden A. A new all-ceramic crown, a dense International Symposium on Ceramics. Chicago: Quintessence, sintered, high-purity alumina coping with porcelain. Acta Odontol 1988:193–208. Scand 1993: 51: 59–64. 34. Miller L. Organizing color in dentistry. J Am Dent Assoc 1987;5. Anusavice KJ. Recent developments in restorative dental 12(special issue):26E–40E. ceramics. J Am Dent Assoc 1993: 124: 72–84. 35. Miller L. Shade matching. J Esthet Dent 1993; 5:143–153. Volume 3 · Number · 3 · 2010 Page 152
  8. 8. Journal of International Dental And Medical Research ISSN 1309-100X Esthetic Failures in Fixed Partial Dentures http://www.ektodermaldisplazi.com/journal.htm Veu N.V.Madhav36. Egger B. Shofu ShadeEye: Der Sinn computergestützter Farbreproduktions-Systeme—ein einjähriger Erfahrungsbericht. Quintessenz Zahntech 1999; 25:409–416.37. Yamamoto M. The idea of a new system for computerized color determination (CCS) system and innovative ceramic materials – The development of the Vintage Halo-CCS system (III). Berlin: Quintessenz, 1997.38. Küppers H. Das The basic law of color theory DuMont, 1978. Volume 3 · Number · 3 · 2010 Page 153